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We report the crystal structure and properties of the one-dimensional S = 1/2 antiferromagnet Cu(2,6-dimethylpyrazine)Br2 with strong intra-chain exchange. At room temperature, its linear spin chains are formed by Cu2+ ions via the non-bonding Br⋯Br contacts. Interestingly, a phase transition from Pmmn to P21/n structure occurs at TS ≈ 248 K below which the [CuBr2]n spin chains become non-linear and the magnetic susceptibility abruptly increases, reflecting the weakening of antiferromagnetic exchange strength. This result evidences the Goodenough–Kanamori rules which claim that a linear super-exchange pathway produces stronger antiferromagnetic coupling. From magnetic susceptibility measurements we find the average intra-chain exchange strength is J/kB ≈ −88.18 K in the low temperature phase. Both magnetic and specific measurements show the absence of magnetic ordering down to 2 K, implying the excellent magnetic one-dimensionality of Cu(2,6-dimethylpyrazine)Br2. We also performed ultra-violet (UV) absorption and photoluminescence measurements which give a semiconducting band gap Δ ≈ 2.79 eV which is consistent with theoretical calculations.

Heterojunction light-emitting diodes (LED) based on n-ZnO/CsPbBr3/p-GaN have been fabricated by using pulsed laser deposition (PLD). The effects of the CsPbBr3 interlayer on the electroluminescence (EL) performance of n-ZnO/p-GaN have been systematically studied. It was found that the CsPbBr3 interlayer plays an important role in the emission performance of the heterojunction LED. By adjusting the thickness of CsPbBr3, the emission peaks of the heterojunction LED change from violet to greenish-yellow, indicating that the electroluminescence characters can be tuned by the CsPbBr3 film thickness. Detailed emission mechanisms influenced by the CsPbBr3 film have been investigated using the Anderson band diagram. The results provide a new method for the fabrication of single-chip white LEDs.

As to the prototypical realization of the famous Mermin–Wagner theorem, two dimensional Heisenberg ferromagnets (2D HFMs) are expected to have no static order at finite temperatures [N. D. Mermin and H. Wagner, Phys. Rev. Lett., 1966, 17, 1133]. However, a perfect 2D HFM with negligible inter-layer exchange is still lacking, impeding studies of its novel properties. Here we report the synthesis, structure, and properties of a new metal–organic single crystal piperazinediium tetrabromocuprate ((C4H12N2)CuBr4, PTBC). The Cu2+ spins form perfect 2D layers which are well separated by organic ligands. Single crystal electron paramagnetic resonance (EPR) and magnetic susceptibility measurements reveal that PTBC is a highly isotropic Heisenberg ferromagnet with a strong intra-layer ferromagnetic exchange J/kB = 31.34(6) K (H‖ab) and 36.54(17) K (H⊥ab). However, it does not order down to 2 K, indicating the negligible inter-layer exchange J′ and ultra-small R ratio (R = J′/J) below 6 × 10−28. This is the smallest R ratio ever reported for a 2D HFM. These results imply that PTBC is by far the best realization of a 2D HFM system. Moreover, the typical single crystal size is as large as 20 mm × 20 mm × 3 mm, making it suitable for studying the magnetic dynamics of a 2D HFM by probes such as inelastic neutron scattering.

We report the crystal structure and properties of the one-dimensional

Background Low-income Chinese women aged 60 years and older are more likely to have multiple non-communicable diseases (NCDs). Neither the independent healthcare system nor the social work system based on the communities is equipped to address their complex needs of health and daily care. The objective was to design and evaluate a social worker-led self-management program for older community-dwelling women with NCDs. MethodsA total of 144 and 138 subjects were recruited in the intervention and control groups from 10 communities in Guangzhou, China. The intervention group was designed as follows: each community recruited two social workers to carry out an NCD self-management program. A health care professional assisted social workers to complete six weekly two-hour sessions. The control group had no extra intervention. The evaluation was conducted at baseline and 12-months follow-up. Outcomes included changes in weight, blood pressure, fasting plasma glucose (FPG), lipid profile, self-management behaviors, and NCD-related knowledge. Results After 12 months, participants had gained 3.6 and 6.6 kg (P=0.025 for between-group difference) in the intervention and control groups, respectively. NCD-related knowledge increased by 15.4% and 11.3% (PP difference=0.031). General linear regression analysis showed that the intervention effects were significant for FPG (P=0.013) and total cholesterol (TC) (P=0.046).ConclusionsA social worker-led NCD self-management program successfully promoted NCD-related knowledge and decreased metabolic risk factors in low-income Cantonese women.Trial registrationChinese Clinical Trial Registry:Evaluation on effectiveness of Non-communicable Disease Self-management models led by social organization. ChiCTR1800015659. Registered 13 April 2018 - Retrospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=15005

CrAs is a well-known helimagnet with the double-helix structure originating from the competition between the Dzyaloshinskii-Moriya interaction (DMI) and antiferromagnetic exchange interaction $J$. By resonant soft-x-ray scattering, we observe the magnetic peak (0 0 ${q}_{m}$) that emerges at the helical transition with ${T}_{S}\phantom{\rule{4pt}{0ex}}\ensuremath{\approx}267.5\phantom{\rule{4pt}{0ex}}\mathrm{K}$. Intriguingly, the helimagnetic domains significantly shrink on cooling below $\ensuremath{\sim}255\phantom{\rule{4pt}{0ex}}\mathrm{K}$, opposite to the conventional thermal effect. The weakening of DMI on cooling is found to play a critical role here. It causes the helical wave vector to vary, ordered spins to rotate, and extra helimagnetic domain boundaries to form at local defects, thus leading to the anomalous shrinkage of helimagnetic domains. Our results indicate that the size of magnetic helical domains can be controlled by tuning DMI in certain helimagnets.

A new frustrated triangular lattice antiferromagnet Na2BaNi(PO4)2 was synthesized by high temperature flux method. The two-dimensional triangular lattice is formed by the Ni2+ ions with S = 1. Its magnetism is highly anisotropic with the Weiss constants θ CW = –6.615 K (H ⊥ c) and –43.979 K (H ∥ c). However, no magnetic ordering is present down to 0.3 K, reflecting strong geometric spin frustration. Our heat capacity measurements show substantial residual magnetic entropy existing below 0.3 K at zero field, implying the presence of low energy spin excitations. These results indicate that Na2BaNi(PO4)2 is a potential spin liquid candidate with spin-1.

Background Stroke is a main cause of death and public health burden in China. The evidence on the burden of different strokes attack attribute to ambient temperature in China is limited. This study aimed to show the characteristics of stroke attack and the attributable risk due to temperature based on hospital admission data in Guangzhou, one of the most developed cities in China. Material and methods From January 1, 2013 to December 31, 2015, 104,432 stroke hospitalizations in Guangzhou residents from 67 hospitals for stroke sentinel surveillance were registered. Characteristics of hospital admissions by gender, age group, calendar year and stroke subtype were analyzed, and distributed lag non-linear models were applied to evaluate the effects of temperature on stroke attack admissions. Results Stroke attack admissions increased from 31,851 to 36,755 through 2013 to 2015, increasing by 15.4%. An increasing trend in the risk of stroke attack with age was observed, irrespectively of stroke subtype and calendar year. People with hypertension were more likely to have an associated stroke than people without that. The effects of cold temperature on attack admissions for CBI and ICH strokes were significant. Overall, the percentages of CBI and ICH attack admissions attribute to cold temperature were 9.06% (95% CI: 1.84, 15.00) and 15.09% (95% CI: 5.86, 21.96), respectively. Besides, elderly people were more vulnerable to cold temperature than the young. Conclusions Measures should be taken to increase public awareness about the ill effects of cold temperature on stroke attack, and educate the public about self-protection.

We report neutron scattering measurements of single-crystalline YFe_{2}Ge_{2} in the normal state, which has the same crystal structure as the 122 family of iron pnictide superconductors. YFe_{2}Ge_{2} does not exhibit long-range magnetic order but exhibits strong spin fluctuations. Like the iron pnictides, YFe_{2}Ge_{2} displays anisotropic stripe-type antiferromagnetic spin fluctuations at (π, 0, π). More interesting, however, is the observation of strong spin fluctuations at the in-plane ferromagnetic wave vector (0, 0, π). These ferromagnetic spin fluctuations are isotropic in the (H, K) plane, whose intensity exceeds that of stripe spin fluctuations. Both the ferromagnetic and stripe spin fluctuations remain gapless down to the lowest measured energies. Our results naturally explain the absence of magnetic order in YFe_{2}Ge_{2} and also imply that the ferromagnetic correlations may be a key ingredient for iron-based materials.

Background Health literacy and health-information seeking behaviour (HISB) play vital roles in health outcome improvements. This study examines the extent of income-related inequality in health literacy and health-information seeking as well as the contributions of the main socioeconomic determinants in China. Methods We analysed representative data of participants aged over 18 years as well as older adults from the Guangzhou Community Health Survey. A concentration index (CI) was used to quantify the degree of income-related inequity in health literacy and health-information seeking. Probit regression models were employed to decompose the CI into the contributions to each factor. Results Results showed a significant pro-rich distribution of adequate health literacy (CI: 0.0602, P < 0.001; horizontal index [HI]: 0.0562, P < 0.001) and HISB from healthcare professionals (CI: 0.105, P < 0.001; HI: 0.0965, P < 0.001). The pro-rich distribution of health literacy was mainly attributable to education background (contribution: 54.76%), whereas income inequalities contributed most to the pro-rich distribution of health-information seeking among an urban population (contribution: 62.53%). Conclusion Public interventions in China to reduce inequality in health literacy and HISBs among the urban population, coupled with easily accessible information sources on health, warrant further attention from policymakers.

First-principles calculations are performed to study the hole doping effect in a series of iron arsenic superconductors, such as the undoped CaFe2As2, CaFeAsF, and the hole-doped CaKFe4As4, KCa2Fe4As4F2, and KFe2As2. Charge occupations in the Fe 3d orbitals are found to show opposite variations when the filling is changed. Compared with the undoped CaFe2As2 and CaFeAsF, charges of the and orbitals decrease while those of the and d xy orbitals increase in the hole-doped materials CaKFe4As4, KCa2Fe4As4F2 and KFe2As2. By further analyzing the Pauli susceptibilities of CaFe2As2 and CaFeAsF, instability is found at the wave vector of , which is responsible for the stripe type antiferromagnetic order. In contrast, the Pauli susceptibilities of CaKFe4As4 and KCa2Fe4As4F2 at are strongly suppressed while the instabilities remain around , which may be the origin of superconductivity. Combining with the calculated orbital-resolved Pauli susceptibility, we conclude that hole doping mainly results in a decrease of charge occupations in the and orbitals, and these three orbitals play dominant roles in controlling the magnetic and superconducting properties in these iron-based superconductors.

BACKGROUND Hypertension is a growing problem worldwide and can often result in a variety of negative health outcomes. The aim of this study was to assess the effects of age at diagnosis, calendar period, and birth cohort on the change in the prevalence rate of hypertension in Guangzhou from 2004 to 2013. METHODS We used data from the Guangzhou Community Health Survey, a population-based study designed by the National Health and Family Planning Commission of the PRC every 5 years. A total of 27,299, 23,467, and 18,362 participants aged 15–79 years completed the survey in 2004, 2009, and 2013, respectively. RESULTS Age effects increased slowly before the age of 42 years but increased rapidly after the age of 42 years, peaking at 79 years. Cohort effects grew slowly before the end of the 1960s but grew quickly after the end of the 1960s. The risk of suffering from hypertension among people born in 1962, 1972, 1982, and 1992 was 1.39, 2.68, 5.55, and 11.53 times, respectively, than that of people born in 1952. The period effects increased 25% from 2004 to 2009 and later declined 27% from 2009 to 2013 in the entire population. There was no gender difference in age effects and period effects, but strong cohort effects on hypertension were observed among males compared with females. CONCLUSIONS For Chinese individuals, the later one is born, the higher the risk is of suffering from hypertension. Strong cohort effects for hypertension were observed among males compared with females, indicating that males are more easily affected by hypertension based on the change in birth cohort.

Background: We aimed to describe the trends and associated factors of hypertension among residents aged ≥15 yr in Guangzhou, China. Methods: Three standardized cross-sectional health surveys were conducted in 2004, 2009 and 2013 using a multi-stage cluster sampling method, and a total of 69128 qualified participants were included in the study. The data were obtained through physical health examination and questionnaire survey. Results: The age-standardised prevalence of hypertension increased from 12.5% to 16.0% between 2004 and 2009 and declined from 16.0% to 14.0% between 2009 and 2013, and crude prevalence respectively was 14.6%, 19.1% and 18.8% in 2004, 2009 and 2013. The proportion of optimal blood pressure dropped from 51.1% to 33.2%, high-normal blood pressure increased from 20.1% to 28.9%, grade 1 hypertension and grade 2 or 3 hypertension increased from 11.5% to 13.6% and 3.9% to 5.8% between 2004 and 2013. The average age was significantly increased (P

Unconventional superconductors are often characterized by numerous competing and even intertwined orders in their phase diagrams. In particular, the electronic nematic phases, which spontaneously break rotational symmetry and often simultaneously involve spin, charge and/or orbital orders, appear conspicuously in both the cuprate and iron-based superconductors. The fluctuations associated with these phases may provide the exotic pairing glue that underlies their high-temperature superconductivity. Helimagnet MnP, the first Mn-based superconductor under pressure, lacks high rotational symmetry. However our resonant soft X-ray scattering (RSXS) experiment discovers novel helical orbital density wave (ODW) orders in this three-dimensional, low-symmetry system, and reveals intertwined ordering phenomena in unprecedented detail. In particular, a ODW forms with half the period of the spin order and fully develops slightly above the spin ordering temperature, their domains develop simultaneously, yet the spin order domains are larger than those of the ODW, and they cooperatively produce another ODW with 1/3 the period of the spin order. These observations provide a comprehensive picture of the intricate interplay between spin and orbital orders in correlated materials, and they suggest that nematic-like physics ubiquitously exists beyond two-dimensional and high-symmetry systems, and the superconducting mechanism of MnP is likely analogous to those of cuprate and iron-based superconductors.

Single crystals of a metal organic complex (C5H12N)CuBr3 (C5H12N = piperidinium, pipH for short) have been synthesized, and the structure was determined by single-crystal X-ray diffraction. (pipH)CuBr3 crystallizes in the monoclinic group C2/c. Edging-sharing CuBr5 units link to form zigzag chains along the c axis, and the neighboring Cu(II) ions with spin-1/2 are bridged by bibromide ions. Magnetic susceptibility data down to 1.8 K can be well fitted by the Bonner-Fisher formula for the antiferromagnetic spin-1/2 chain, giving the intrachain magnetic coupling constant J ≈ -17 K. At zero field, (pipH)CuBr3 shows three-dimensional (3D) order below TN = 1.68 K. Calculated by the mean-field theory, the interchain coupling constant J' = -0.91 K is obtained and the ordered magnetic moment m0 is about 0.23 μB. This value of m0 makes (pipH)CuBr3 a rare compound suitable to study the 1D-3D dimensional cross-over problem in magnetism, since both 3D order and one-dimensional (1D) quantum fluctuations are prominent. In addition, specific heat measurements reveal two successive magnetic transitions with lowering temperature when external field μ0H ≥ 3 T is applied along the a' axis. The μ0H-T phase diagram of (pipH)CuBr3 is roughly constructed.

Genetic variation of NEDD4L has been associated with hypertension and related phenotypes with conflicting results, probably attributable to gender-, age- and ethnicity-related variations in its phenotypic expression. We evaluated the association of three representative polymorphisms in NEDD4L (rs2288774, rs3865418 and rs4149601) with essential hypertension (EH) in a community-based sample of men (n = 1029) and women (n = 869) belonging to Han Chinese, Southern China, to probe whether gender interacts with NEDD4L in contributing to the risk of EH. In this population sample, rs4149601 was excluded from further analysis due to deviation from Hardy-Weinberg equilibrium. For two other variants tested, the allele frequencies and genotype distributions did not differ between cases and controls (p 0.05) when both genders were combined. However, sex-stratified analysis revealed that the distribution of the dominant model of rs2288774 (TC + CC versus TT) and the additive and dominant (CT + TT versus CC) models of rs3865418 differed significantly between cases and controls in men (p = 0.044, 0.041 and 0.016, respectively) but not in women. After adjusting for confounding factors, logistic regression analysis showed that rs2288774 and rs3865418 (in the dominant model) were still significantly associated with EH (rs2288774: OR = 0.73, 95% CI = 0.57-0.95, p = 0.017 and rs3865418: OR = 0.71, 95% CI = 0.55-0.92, p = 0.009) in men. There was a significant interaction between the NEDD4L genotype and gender (p for interaction: 0.046 for rs2288774 and 0.033 for rs3865418). Genetic variation in NEDD4L may have sex-dependent effects in the development of EH in Han Chinese. Previous studies that ignore gender-specific effects in their design and interpretation could have failed to identify a uniform conclusion.

Objective data on hypertension prevalence and management in local areas are scarce. We assessed the prevalence of hypertension and its management in Guangzhou adult population.A stratified multistage cluster sampling with probability proportional to size method was used in this survey. Information on a total of 23 939 respondents, aged 15 years old or above, having a gender ratio of 0.997 (male versus female) with completed questionnaire and blood pressure measurement, was obtained. Hypertension was defined as having a mean SBP of at least 140 mm Hg, a DBP of at least 90 mm Hg, and/or the prescription of antihypertensive drugs. Information related to the history of hypertension and treatment of hypertension was collected through a questionnaire.The prevalence of hypertension was 11.8%. Among patients with hypertension, 54.4% were aware of their elevated BP, 49.3% had treatment, and 23.3% achieved targeted BP control. Among those who were aware of their hypertension, 90.4% underwent treatment, and among those who were treated, 43.6% were well controlled. Although the prevalence, awareness and treatment of hypertension varied significantly among adults with several social economics status, the control of hypertension did not show significant differences. Among treated patients, the control of hypertension showed significant differences among adults with education, occupation, insurance and income.It is the first time for Guangzhou to describe epidemic and management of hypertension. A baseline was established, which could provide useful information not only to policymakers but also to developing countries with a close urbanization and aging rate similar to Guangzhou.

Heavily electron-doped iron-selenide high-transition-temperature (high-T c) superconductors, which have no hole Fermi pockets, but have a notably high T c, have challenged the prevailing s ± pairing scenario originally proposed for iron pnictides containing both electron and hole pockets. The microscopic mechanism underlying the enhanced superconductivity in heavily electron-doped iron-selenide remains unclear. Here, we used neutron scattering to study the spin excitations of the heavily electron-doped iron-selenide material Li0.8Fe0.2ODFeSe (T c = 41 K). Our data revealed nearly ring-shaped magnetic resonant excitations surrounding (π, π) at ∼21 meV. As the energy increased, the spin excitations assumed a diamond shape, and they dispersed outward until the energy reached ∼60 meV and then inward at higher energies. The observed energy-dependent momentum structure and twisted dispersion of spin excitations near (π, π) are analogous to those of hole-doped cuprates in several aspects, thus implying that such spin excitations are essential for the remarkably high T c in these materials., The microscopic mechanism underlying an enhanced superconductivity in electron-doped iron selenide superconductor remains unclear. Here, Pan et al. report the spin excitations of Li0.8Fe0.2ODFeSe, revealing analogous momentum structure and dispersion to hole-doped cuprates.

In low-dimensional electron systems, charge density waves (CDW) and superconductivity are two of the most fundamental collective quantum phenomena. For all known quasi-two-dimensional superconductors, the origin and exact boundary of the electronic orderings and superconductivity are still attractive problems. Through transport and thermodynamic measurements, we report on the field-temperature phase diagram in 2H-TaS2 single crystals. We show that the superconducting transition temperature (Tc) increases by one order of magnitude from temperatures at 0.98 K up to 9.15 K at 8.7 GPa when the Tc becomes very sharp. Additionally, the effects of 8.7 GPa illustrate a suppression of the CDW ground state, with critically small Fermi surfaces. Below the Tc the lattice of magnetic flux lines melts from a solid-like state to a broad vortex liquid phase region. Our measurements indicate an unconventional s-wave-like picture with two energy gaps evidencing its multi-band nature.

An essential step toward elucidating the mechanism of superconductivity is to determine the sign/phase of superconducting order parameter, as it is closely related to the pairing interaction. In conventional superconductors, the electron-phonon interaction induces attraction between electrons near the Fermi energy and results in a sign-preserved s-wave pairing. For high-temperature superconductors, including cuprates and iron-based superconductors, prevalent weak coupling theories suggest that the electron pairing is mediated by spin fluctuations which lead to repulsive interactions, and therefore that a sign-reversed pairing with an s+-or d-wave symmetry is favored. Here, by using magnetic neutron scattering, a phase sensitive probe of superconducting gap, we report the observation of a transition from the sign-reversed to sign-preserved Cooper-pairing symmetry with insignificant changes in Tc in the S-doped iron selenide superconductors KxFe2-y(Se1-zSz)2. We show that a rather sharp magnetic resonant mode well below the superconducting gap (2delta) in the undoped sample (z = 0) is replaced by a broad hump structure above 2delta under 50% S doping. These results cannot be readily explained by simple spin fluctuation-exchange pairing theories and, therefore, multiple pairing channels are required to describe superconductivity in this system. Our findings may also yield a simple explanation for the sometimes contradictory data on the sign of the superconducting order parameter in iron-based materials., 11 pages, 4 figures, Supplemental Materials available upon request

The superconducting ground state of the newly discovered superconductor Cs$_2$Cr$_3$As$_3$ with a quasi-one-dimensional crystal structure ($T_{\bf c}\sim$ 2.1(1) K) has been investigated using magnetization and muon-spin relaxation or rotation ($\mu$SR), both zero-field (ZF) and transverse-field (TF), measurements. Our ZF $\mu$SR measurements reveal the presence of spin fluctuations below 4 K and the ZF relaxation rate ($\lambda$) shows enhancement below $T_{\bf c}\sim$ 2.1 K, which might indicate that the superconducting state is unconventional. This observation suggests that the electrons are paired via unconventional channels such as spin fluctuations, as proposed on the basis of theoretical models. Our analysis of the TF $\mu$SR results shows that the temperature dependence of the superfluid density is fitted better with a nodal gap structure than an isotropic s-wave model for the superconducting gap. The observation of a nodal gap in Cs$_2$Cr$_3$As$_3$ is consistent with that observed in the isostructural K$_2$Cr$_3$As$_3$ compound through TF $\mu$SR measurements. Furthermore, from our TF $\mu$SR study we have estimated the magnetic penetration depth $\lambda_{\mathrm{L}}$$(0)$ = 954 nm, superconducting carrier density $n_s = 4.98 \times 10^{26}~ $m$^{-3}$, and carrier's effective-mass enhancement $m^*$ = 1.61m$_{e}$., Comment: 7 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:1505.05743

Elucidating the microscopic origin of nematic order in iron-based superconducting materials is important because the interactions that drive nematic order may also mediate the Cooper pairing. Nematic order breaks fourfold rotational symmetry in the iron plane, which is believed to be driven by either orbital or spin degrees of freedom. However, as the nematic phase often develops at a temperature just above or coincides with a stripe magnetic phase transition, experimentally determining the dominant driving force of nematic order is difficult. Here, we use neutron scattering to study structurally the simplest iron-based superconductor FeSe, which displays a nematic (orthorhombic) phase transition at $T_s=90$ K, but does not order antiferromagnetically. Our data reveal substantial stripe spin fluctuations, which are coupled with orthorhombicity and are enhanced abruptly on cooling to below $T_s$. Moreover, a sharp spin resonance develops in the superconducting state, whose energy (~4 meV) is consistent with an electron boson coupling mode revealed by scanning tunneling spectroscopy, thereby suggesting a spin fluctuation-mediated sign-changing pairing symmetry. By normalizing the dynamic susceptibility into absolute units, we show that the magnetic spectral weight in FeSe is comparable to that of the iron arsenides. Our findings support recent theoretical proposals that both nematicity and superconductivity are driven by spin fluctuations., Comment: 19 pages, 8 figures

A quantum spin liquid is an exotic quantum state of matter in which spins are highly entangled and remain disordered down to zero temperature. Such a state of matter is potentially relevant to high-temperature superconductivity and quantum-information applications, and experimental identification of a quantum spin liquid state is of fundamental importance for our understanding of quantum matter. Theoretical studies have proposed various quantum-spin-liquid ground states, most of which are characterized by exotic spin excitations with fractional quantum numbers (termed `spinon'). Here, we report neutron scattering measurements that reveal broad spin excitations covering a wide region of the Brillouin zone in a triangular antiferromagnet YbMgGaO4. The observed diffusive spin excitation persists at the lowest measured energy and shows a clear upper excitation edge, which is consistent with the particle-hole excitation of a spinon Fermi surface. Our results therefore point to a QSL state with a spinon Fermi surface in YbMgGaO4 that has a perfect spin-1/2 triangular lattice as in the original proposal of quantum spin liquids., Comment: 23 pages, 10 figures

Elucidating the nature of the magnetism of a high-temperature superconductor is crucial for establishing its pairing mechanism. The parent compounds of the cuprate and iron-pnictide superconductors exhibit N\'eel and stripe magnetic order, respectively. However, FeSe, the structurally simplest iron-based superconductor, shows nematic order (Ts = 90 K), but not magnetic order in the parent phase, and its magnetic ground state is intensely debated. Here, we report inelastic neutron-scattering experiments that reveal both stripe and N\'eel spin fluctuations over a wide energy range at 110 K. On entering the nematic phase, a substantial amount of spectral weight is transferred from the N\'eel to the stripe spin fluctuations. Moreover, the total fluctuating magnetic moment of FeSe is ~ 60% larger than that in the iron pnictide BaFe2As2. Our results suggest that FeSe is a novel S = 1 nematic quantum-disordered paramagnet interpolating between the N\'eel and stripe magnetic instabilities., Comment: Supplementary information included; accepted by Nature Communications

The superconducting state of the newly discovered superconductor K$_2$Cr$_3$As$_3$ with a quasi-one-dimensional crystal structure ($T_{\bf c}\sim$ 6 K) has been investigated by using magnetization and muon-spin relaxation or rotation ($\mu$SR) measurements. Our analysis of the temperature dependence of the superfluid density obtained from the transverse field (TF) $\mu$SR measurements fit very well to an isotropic $s$-wave character for the superconducting gap. Furthermore a similarly good fit can also be obtained using a $d$-wave model with line nodes. Our zero-field $\mu$SR measurements do reveal very weak evidence of the spontaneous appearance of an internal magnetic field near the transition temperature, which might indicate that the superconducting state is not conventional. This observation suggests that the electrons are paired via unconventional channels such as spin fluctuations, as proposed on the basis of theoretical models of K$_2$Cr$_3$As$_3$. Furthermore, from our TF $\mu$SR study the magnetic penetration depth $\lambda_L$, superconducting carrier density $n_s$, and effective-mass enhancement $m^*$ have been estimated to be $\lambda_L(0)$ = 454(4) nm, $n_s$ = 2.4$\times$10$^{27}$ carriers/m$^3$, and $m^*$ = 1.75 $m_e$, respectively.

Single crystals of the title compound are prepared by the evaporation method from CuBr2 dissolved in EtOH, aqueous HBr, and piperidine (7 d) and characterized by single crystal XRD, specific heat, and magnetic susceptibility measurements.

Introduction This article reports on the prevalence of noncommunicable diseases (NCDs) and their risk factors in the city of Guangzhou, China, and shows a trend toward epidemic proportions when municipal data are compared with provincial data. Methods We conducted the Guangzhou Community Health Survey in the 12 administrative districts of Guangzhou to learn about NCDs and their risk factors. A community-based, face-to-face survey with a stratified multistage cluster sampling was used. Information was gathered on 27,743 respondents, aged 0 to 108 years, with a male to female ratio of 1 to 1. All participants completed a questionnaire, and those aged 15 years or older had a physical examination. Survey results were compared with the provincial results of the 2002 Guangdong Nutrition and Health Survey (GNHS). Results The data were weighted to the respondent’s probability of selection and to the age- and sex-specific population. Prevalence estimate of self-reported NCDs was 16.0%. Hypertension and diabetes were reported as the most important NCDs. Of those who responded, 6.8% reported having more than 2 chronic conditions. The adjusted prevalence of hypertension decreased by 13.3% since 2002. Awareness, treatment, and control of hypertension and diabetes were improved. The estimated prevalence of current smoking decreased, and the prevalence of former smoking increased from 2002. However, the prevalence of overweight and obesity, especially central obesity, increased. Conclusion Results were encouraging with regard to hypertension and diabetes. However, the unfavorable trends, especially for overweight, central obesity, and passive smoking, call for additional action.

Most unconventional superconductors, including cuprates and iron-based superconductors, are derived from chemical doping or application of pressure on their collinearly magnetic-ordered parent compounds[1-5]. The recently discovered pressure-induced superconductor CrAs, as a rare example of a non-collinear helimagnetic superconductor, has therefore generated great interest in understanding microscopic magnetic properties and their interplay with superconductivity [6-8]. Unlike cuprates and iron based superconductors where the magnetic moment direction barely changes upon doping, here we show that CrAs exhibits a spin reorientation from the ab plane to the ac plane, along with an abrupt drop of the magnetic propagation vector at a critical pressure (Pc~0.6 GPa). This magnetic phase transition coincides with the emergence of bulk superconductivity, indicating a direct connection between magnetism and superconductivity. With further increasing pressure, the magnetic order completely disappears near the optimal Tc regime (P~0.94 GPa). Moreover, the Cr magnetic moments between nearest neighbors tend to be aligned antiparallel with increasing pressure toward the optimal superconductivity regime. Our findings suggest that the non-collinear helimagnetic order is strongly coupled to structural and electronic degrees of freedom, and that antiferromagnetic correlations associated with the low magnetic vector phase are crucial for superconductivity., Comment: Supplementary Information included

OBJECTIVES: This research aimed to (i) determine the prevalence of metabolic syndrome (MetS) and its components; (ii) assess factors associated with MetS, and (iii) define optimal ethnic-specific cutoffs of obesity- and atherogenic-based markers to predict MetS among postmenopausal women in rural Canton. METHODOLOGY/PRINCIPAL FINDINGS: The Rural Canton Diabetes and Metabolic Disorders Study, a population based cross-sectional study, was conducted during 2011-2012 in Canton. In person interviews, blood glucose and lipid measurements were completed for 4,706 postmenopausal women who did not receive hormone replacement therapy. MetS was diagnosed using criteria of the Joint-Interim-Statement (JIS), the International-Diabetes-Federation (IDF) and the Modified-Third-Adult-Treatment-Panel (M-ATPIII). Age-standardized prevalence of MetS was 38.4%, 28.8%, and 37.1% according to JIS, IDF, and M-ATPIII criteria, respectively. Excellent agreement was observed between three definitions (κ ≥ 0.79), in particular between JIS and ATPIII (κ = 0.98, 95%CI: 0.97-0.98). Factors positively associated with MetS were living in Southern Canton, personal income, current smoking, higher BMI, and family history of cardiovascular disease. However, regular leisure-time physical activity can have protective effects. The optimal cutoff values for waist-circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio(WHtR), BMI, HDL-cholesterol to total cholesterol ratio (HDL/TC), HDL-cholesterol to LDL-cholesterol ratio (HDL/LDL), and triglyceride to HDL-cholesterol ratio (TG/HDL) that predicted the presence of MetS were 79.5 cm, 0.86, 0.53, 22.47 kg/m(2), 0.33, 0.68, and 0.88, respectively. CONCLUSIONS: This study highlights the importance of MetS among postmenopausal women in rural Canton. Our findings contribute to help selecting Cantonese-specific markers to predict MetS and support the need to establish educational program for promoting healthy-lifestyles among this population.

We measured the resistivity and the specific heat of CsFe${}_{2}$As${}_{2}$ single crystals, which were grown by using a self-flux method. The CsFe${}_{2}$As${}_{2}$ crystal shows a sharp superconducting transition at 1.8 K with a transition width of 0.1 K. The sharp superconducting transition and pronounced jump in specific heat indicate high quality of the crystals. A large $\ensuremath{\Delta}{C}_{p}/{T}_{c}$ accompanying a very low ${T}_{c}$, nonexponential dependence of the lowest temperature $\ensuremath{\Delta}{C}_{p}/T$ and an ${H}^{1/2}$ dependence of $\ensuremath{\Delta}\ensuremath{\gamma}(H)$ are observed in the superconducting-state specific heat. Combined with the fitting results by the $\ensuremath{\alpha}$ model for the superconducting-state specific heat, a pairing symmetry with nodal gaps was suggested in CsFe${}_{2}$As${}_{2}$.

NEDD4L is a candidate gene for hypertension, both functionally and genetically. Recently, studies showed evidence for the association of NEDD4L with obesity, a key intermediate phenotype in hypertension. To further investigate the relationship between NEDD4L and body mass-related phenotypes, we genotyped three common variants (rs2288774, rs3865418 and rs4149601) in a population-based study of 892 unrelated Han Cantonese using the Sequenom MALDI-TOF-MS platform. Allele frequencies and genotype distribution were calculated in lean controls and overweight/obese cases and analyzed for association by the Chi-squared test and Logistic regression. Linear regression analysis was used to analyze the effect of individual genotypes on quantitative traits. Multivariate analyses demonstrated that the minor allele of rs4149601(A = 20.9%) was associated with a 2.60 kg, 2.78 cm and 0.97 kg/m2 decrease per allele copy in weight, waist and BMI, respectively. Carriers of this allele also had a significant lower risk of overweight/obesity (p < 0.0001, OR = 0.52, 95% CI: 0.37–0.74) as compared to non-carriers. However, no significant association between genotypes at rs2288774 and rs3865418 and covariate-adjusted overweight/obesity or any related phenotypes was observed. These results suggested that the functional variant of NEDD4L, rs4149601, may be associated with obesity and related phenotypes, and further genetic and functional studies are required to understand its role in the manifestation of obesity.

The thermal conductivity of iron-based superconductor CsFe${}_{2}$As${}_{2}$ single crystal (${T}_{c}=1.81$ K) was measured down to 50 mK. A significant residual linear term ${\ensuremath{\kappa}}_{0}/T=1.27$ mW K${}^{\ensuremath{-}2}$ cm${}^{\ensuremath{-}1}$ is observed in zero magnetic field, which is about 1/10 of the normal-state value in upper critical field ${H}_{c2}$. In low magnetic field, ${\ensuremath{\kappa}}_{0}/T$ increases rapidly with field. The normalized ${\ensuremath{\kappa}}_{0}/T(H)$ curve for our CsFe${}_{2}$As${}_{2}$ (with residual resistivity ${\ensuremath{\rho}}_{0}=1.80$ $\ensuremath{\mu}\ensuremath{\Omega}$ cm) lies between the dirty KFe${}_{2}$As${}_{2}$ (with ${\ensuremath{\rho}}_{0}=3.32$ $\ensuremath{\mu}\ensuremath{\Omega}$ cm) and the clean KFe${}_{2}$As${}_{2}$ (with ${\ensuremath{\rho}}_{0}=0.21$ $\ensuremath{\mu}\ensuremath{\Omega}$ cm), which is consistent with its impurity level. These results strongly suggest a nodal superconducting gap in CsFe${}_{2}$As${}_{2}$, similar to its sister compound KFe${}_{2}$As${}_{2}$.

Superconductivity arises from pairing of mobile electrons. The symmetry of the electron-pair wave function contains important clues about the mechanism underlying the pairing. A Chinese-Korean experimental collaboration carries out element-selective substitutional doping of BaFe${}_{2}$As${}_{2}$ and searches for the pairing symmetry of the resulting iron-based superconductors.

The thermal conductivity $\kappa$ of superconductor Ir$_{1-x}$Pt$_{x}$Te$_2$ ($x$ = 0.05) single crystal with strong spin-orbital coupling was measured down to 50 mK. The residual linear term $\kappa_0/T$ is negligible in zero magnetic field. In low magnetic field, $\kappa_0/T$ shows a slow field dependence. These results demonstrate that the superconducting gap of Ir$_{1-x}$Pt$_{x}$Te$_2$ is nodeless, and the pairing symmetry is likely conventional s-wave, despite the existence of strong spin-orbital coupling and a quantum critical point., Comment: 5 pages, 4 figures

occurring at the upper critical field Hc2, is demonstrated from the �(T) � T near Hc2 and �(T) � T 2 when further increasing field. Large residual linear term �0/T at zero field and the rapid increase of �(H)/T at low field indicate that the superconducting gap in Ce2PdIn8 has nodes, likely d-wave symmetry. The sharp jump of �(H)/T near Hc2 gives evidence for a first-order phase transition at low temperature. These results suggest the existence of a low-temperature-high-field Q phase in Ce2PdIn8, where magnetic order is directly coupled to d-wave superconductivity, as in CeCoIn5.

Ordered GeSi nanoislands were fabricated in combination of self-assembly and nanosphere lithography on Si (001) substrates. Well ordered pits in a hexagonal lattice on Si (001) substrates are readily obtained via nanosphere lithography. The preferential nucleation of GeSi nanoislands in the pits results in laterally ordered nanoislands on such prepatterned Si (001) surface during Ge deposition. Multilayer GeSi nanoislands separated by thin Si spacer layers were also realized. The vertical alignment of nanoislands along the growth direction can give rise to three-dimensionally ordered nanoislands or nanoisland crystal. To explore the optoelectronic properties of ordered nanoislands, A Si p-i-n diode embedded with multilayer ordered GeSi nanoislands were fabricated. Photoluminescence of the samples with multilayer GeSi nanoislands were studied.

We have successfully synthesized the new S = 1/2 anisotropic kagome antiferromagnet ZnCu3(OH)(6)SO4 and determined its structure by synchrotron x-ray diffraction. No magnetic ordering is observed down to 50 mK, despite a moderately high Weiss temperature of Theta(w)similar to-79 K, indicating that the compound is a new quantum spin liquid (QSL) candidate. A linear temperature dependence of the magnetic heat capacity is found at 6 similar to 15K and below 0.6 K. Temperature-independent intrinsic susceptibilities are observed exactly in both temperature ranges. This consistently suggests a gapless QSL below 0.6 K, which may evolve from an unconventional quantum spin state at higher temperatures (6 similar to 15 K).

The specific heat and thermal conductivity of the insulating ferrimagnet Y$_3$Fe$_5$O$_{12}$ (Yttrium Iron Garnet, YIG) single crystal were measured down to 50 mK. The ferromagnetic magnon specific heat $C$$_m$ shows a characteristic $T^{1.5}$ dependence down to 0.77 K. Below 0.77 K, a downward deviation is observed, which is attributed to the magnetic dipole-dipole interaction with typical magnitude of 10$^{-4}$ eV. The ferromagnetic magnon thermal conductivity $\kappa_m$ does not show the characteristic $T^2$ dependence below 0.8 K. To fit the $\kappa_m$ data, both magnetic defect scattering effect and dipole-dipole interaction are taken into account. These results complete our understanding of the thermodynamic and thermal transport properties of the low-lying ferromagnetic magnons., Comment: 5 pages, 5 figures

The thermal conductivity of optimally doped NaFe$_{0.972}$Co$_{0.028}$As ($T_c \sim$ 20 K) and overdoped NaFe$_{0.925}$Co$_{0.075}$As ($T_c \sim$ 11 K) single crystals were measured down to 50 mK. No residual linear term $\kappa_0/T$ is found in zero magnetic field for both compounds, which is an evidence for nodeless superconducting gap. Applying field up to $H$ = 9 T ($\approx H_{c2}/4$) does not noticeably increase $\kappa_0/T$ in NaFe$_{1.972}$Co$_{0.028}$As, which is consistent with multiple isotropic gaps with similar magnitudes. The $\kappa_0/T$ of overdoped NaFe$_{1.925}$Co$_{0.075}$As shows a relatively faster field dependence, indicating the increase of the ratio between the magnitudes of different gaps, or the enhancement of gap anisotropy upon increasing doping., Comment: 5 pages, 4 figures