Evidence for an emergent anomalous metallic state in compressed titanium.

The anomalous metallic state (AMS) emerging from a quantum superconductor-to-metal transition is a subject of great current interest since this exotic quantum state exhibits unconventional transport properties that challenge the core physics principles of Fermi liquid theory. As the AMS concept is historically derived from disordered two-dimensional (2D) systems, related studies have predominately concentrated on 2D materials. The AMS behaviors in three-dimensional (3D) systems have been rarely reported to date, which raises intriguing questions on the fundamental nature of pertinent physics. Here, we report experimental evidence for a 3D AMS in highly compressed titanium metal that exhibits superconductivity with a critical temperature (Tc) reaching near-record 25.1 K among elemental superconductors, offering a favorable material template for exploring 3D AMS. At sufficiently strong magnetic fields, unusual transport behaviors set in over a wide pressure range, showcasing AMS hallmarks of a low-temperature saturation resistance below the Drude value and giant positive magnetoresistance. These findings reveal a 3D AMS in simple elemental systems and, more importantly, provide a fresh platform for probing the decades-long enigmatic underlying physics.

Superconductivity above 105 K in Nonclathrate Ternary Lanthanum Borohydride below Megabar Pressure.

Hydrides are promising candidates for achieving room-temperature superconductivity, but a formidable challenge remains in reducing the stabilization pressure below a megabar. In this study, we successfully synthesized a ternary lanthanum borohydride by introducing the nonmetallic element B into the La-H system, forming robust B-H covalent bonds that lower the pressure required to stabilize the superconducting phase. Electrical transport measurements confirm the presence of superconductivity with a critical temperature (Tc) of up to 106 K at 90 GPa, as evidenced by zero resistance and Tc shift under an external magnetic field. X-ray diffraction and transport measurements identify the superconducting compound as LaB2H8, a nonclathrate hydride, whose crystal structure remains stable at pressures as low as ∼ half megabar (59 GPa). Stabilizing superconductive stoichiometric LaB2H8 in a submegabar pressure regime marks a substantial advancement in the quest for high-Tc superconductivity in polynary hydrides, bringing us closer to the ambient pressure conditions.

Observation of Iron with Eight Coordination in Iron Trifluoride under High Pressure.

The chemistry of hypercoordination has been a subject of fundamental interest, especially for understanding structures that challenge conventional wisdom. The small ionic radii of Fe ions typically result in coordination numbers of 4 or 6 in stable Fe-bearing ionic compounds. While 8-coordinated Fe has been observed in highly compressed oxides, the pursuit of hypercoordinated Fe still faces significant challenges due to the complexity of synthesizing the anticipated compound with another suitable anion. Through first-principles simulation and advanced crystal structure prediction methods, we predict that an orthorhombic phase of FeF3 with exclusively 8-coordinated Fe is energetically stable above 18 GPa-a pressure more feasibly achieved compared to oxides. Inspired by this theoretical result, we conducted extensive experiments using a laser-heated diamond anvil cell technique to investigate the crystal structures of FeF3 at high-pressure conditions. We successfully synthesized the predicted orthorhombic phase of FeF3 at 46 GPa, as confirmed by in situ experimental X-ray diffraction data. This work establishes a new ionic compound featuring rare 8-coordinated Fe in a simple binary Fe-bearing system and paves the way for discovering Fe hypercoordination in similar systems.

Stoichiometric Ternary Superhydride LaBeH_{8} as a New Template for High-Temperature Superconductivity at 110 K under 80 GPa.

The search for high-temperature superconducting superhydrides has recently moved into a new phase by going beyond extensively probed binary compounds and focusing on ternary ones with vastly expanded material types and configurations for property optimization. Theoretical and experimental works have revealed promising ternary compounds that superconduct at or above room temperature, but it remains a pressing challenge to synthesize stoichiometric ternary compounds with a well-resolved crystal structure that can host high-temperature superconductivity at submegabar pressures. Here, we report on the successful synthesis of ternary LaBeH_{8} obtained via compression in a diamond anvil cell under 110-130 GPa. X-ray diffraction unveils a rocksalt-like structure composing La and BeH_{8} units in the lattice. Transport measurements determined superconductivity with critical temperature T_{c} up to 110 K at 80 GPa, as evidenced by a sharp drop of resistivity to zero and a characteristic shift of T_{c} driven by a magnetic field. Our experiment establishes the first superconductive ternary compound with a resolved crystal structure. These findings raise the prospects of rational development of the class of high-T_{c} superhydrides among ternary compounds, opening greatly expanded and more diverse structural space for exploration and discovery of superhydrides with enhanced high-T_{c} superconductivity.

High-Temperature Superconducting Phase in Clathrate Calcium Hydride CaH_{6} up to 215 K at a Pressure of 172 GPa.

The recent discovery of superconductive rare earth and actinide superhydrides has ushered in a new era of superconductivity research at high pressures. This distinct type of clathrate metal hydrides was first proposed for alkaline-earth-metal hydride CaH_{6} that, however, has long eluded experimental synthesis, impeding an understanding of pertinent physics. Here, we report successful synthesis of CaH_{6} and its measured superconducting critical temperature T_{c} of 215 K at 172 GPa, which is evidenced by a sharp drop of resistivity to zero and a characteristic decrease of T_{c} under a magnetic field up to 9 T. An estimate based on the Werthamer-Helfand-Hohenberg model gives a giant zero-temperature upper critical magnetic field of 203 T. These remarkable benchmark superconducting properties place CaH_{6} among the most outstanding high-T_{c} superhydrides, marking it as the hitherto only clathrate metal hydride outside the family of rare earth and actinide hydrides. This exceptional case raises great prospects of expanding the extraordinary class of high-T_{c} superhydrides to a broader variety of compounds that possess more diverse material features and physics characteristics.

Disproportionation of SO_{2} at High Pressure and Temperature.

Materials once suffered at high-pressure and high-temperature (HPHT) conditions often exhibit exotic phenomena that defy conventional wisdom. The behaviors of sulfur dioxide (SO_{2}), one of the archetypal simple molecules, at HPHT conditions have attracted a great deal of attention due to its relevance to the S cycle between deep Earth and the atmosphere. Here we report the discovery of an unexpected disproportionation of SO_{2} via bond breaking into elemental S and sulfur trioxide (SO_{3}) at HPHT conditions through a jointly experimental and theoretical study. Measured x-ray diffraction and Raman spectroscopy data allow us to solve unambiguously the crystal structure (space group R3[over ¯]c) of the resultant SO_{3} phase that shows an extended framework structure formed by vertex-sharing octahedra SO_{6}. Our findings lead to a significant extension of the phase diagram of SO_{2} and suggest that SO_{2}, despite its abundance in Earth's atmosphere and ubiquity in other giant planets, is not a stable compound at HPHT conditions relevant to planetary interiors, providing important implications for elucidating the S chemistry in deep Earth and other giant planets.

Erratum: High-Temperature Superconducting Phase in Clathrate Calcium Hydride CaH_{6} up to 215 K at a Pressure of 172 GPa [Phys. Rev. Lett. 128, 167001 (2022)].

This corrects the article DOI: 10.1103/PhysRevLett.128.167001.

Predicted crystal structures of xenon and alkali metals under high pressures.

The pressure-induced reaction between xenon (Xe) and other non-inert gas elements and the resultant crystal structures have attracted great interest. In this work, we carried out extensive simulations on the crystal structures of Xe-alkali metal (Xe-AM) systems under high pressures. Among all predicted compounds, KXe and RbXe are found to become stable at a pressure of ∼16 GPa by adopting a cubic symmetry of space group Pm3̄m. The stabilization of KXe and RbXe requires slightly lower pressure compared with that of previously reported CsXe (25 GPa), interestingly, which is in contrast to the electronegativity order of the AMs and unexpected. Our simulations also indicate that all predicted Xe compounds contain negatively charged Xe. Moreover, our in-depth analysis indicates that the occupation of AM d-orbitals plays a critical role in stabilizing these Xe-bearing compounds. These results shed light on the understanding of the reaction between Xe and AMs and the formation mechanism of the resultant crystal structures.

Intrauterine devices migrated into the bladder: two case reports and literature review.

BACKGROUND: Intrauterine devices (IUD) are widely used all over the world. One of the most serious complications is uterine perforation, and it is very rare for the IUD to penetrate the bladder after perforation. Here we report two cases of IUD migration into the bladder, and review the literature to analyze the possible causes and solutions of such complications. CASE PRESENTATION: Case NO. 1 is a 37-year-old female who presented lower urinary tract symptoms for a year. Cystoscopy showed that a strip of metal penetrated into the bladder, and the surface was covered with stones. The patient underwent cystotomy and foreign body removal under general anesthesia. Case NO. 2 is a 46-year-old woman who previously inserted an IUD in 1998, but she had an unexpected pregnancy in 1999. Her doctor believed that "the IUD had spontaneously expulsed" and a new IUD was inserted after her pregnancy was terminated. Her CT scan showed an IUD on the left side of the bladder and another IUD in the uterus. Her foreign body was removed by cystotomy. CONCLUSION: Patients with IUD should be suggested to check the device regularly, and those who with a missed IUD have to rule out the possibility of IUD migration. For patients with IUD combined with lower urinary tract symptoms, it is necessary to be aware of whether IUD perforation affects the bladder.

Reconciliation of Experiments and Theory on Transport Properties of Iron and the Geodynamo.

We measure the electrical resistivity of hcp iron up to ∼170 GPa and ∼3000 K using a four-probe van der Pauw method coupled with homogeneous flattop laser heating in a DAC, and compute its electrical and thermal conductivity by first-principles molecular dynamics including electron-phonon and electron-electron scattering. We find that the measured resistivity of hcp iron increases almost linearly with temperature, and is consistent with our computations. The results constrain the resistivity and thermal conductivity of hcp iron to ∼80±5 µΩ cm and ∼100±10 W m^{-1} K^{-1}, respectively, at conditions near the core-mantle boundary. Our results indicate an adiabatic heat flow of ∼10±1 TW out of the core, supporting a present-day geodynamo driven by thermal and compositional convection.

An increasing prevalence of non-GII.4 norovirus genotypes in acute gastroenteritis outbreaks in Huzhou, China, 2014-2018.

Since 2014, novel non-GII.4 norovirus (NoV) genotypes continue to be reported as the main cause of outbreaks worldwide. In this study, we analyzed the epidemiological and genetic features of NoV outbreaks from July 2014 to June 2018 in Huzhou, China. A total of 450 stool samples collected from 51 AGE outbreaks were tested for NoVs by real-time RT PCR. Partial polymerase and capsid sequences of NoV-positive samples were amplified and sequenced for phylogenetic analysis. NoVs were found to be responsible of 84.3% of AGE outbreaks in Huzhou over the past 5 years. Most NoV outbreaks were reported in the cool months (November-March) and occurred in primary schools and kindergartens. Changes in the diversity of genotypes and the distribution of predominant types were observed in recent years. At least eight genotypes were identified, and 91.9% of the genotyped outbreaks were caused by non-GII.4 strains. The top three circulating genotypes during the study period were GII.2[P16], GII.3[P12], and GII.17[P17]. The predominant NoV genotypes in outbreaks have changed from GII.4 variants to GII.17[P17] in 2014-2015, GII.3[P12] in 2015-2016, and then GII.2[P16] in 2016-2018. Non-GII.4 NoVs play an increasingly important role in outbreaks in Huzhou. Continuous surveillance is needed to monitor the emergence of novel NoV strains and help control NoV outbreaks in the next epidemic season.

Mechanical properties and superconductivity in two-dimensional B2O under extreme strain.

Because of the particular characteristics of layered materials, searching for new two-dimensional (2D) structures has become the foundation of future device manufacture. Using first-principles calculations and theoretical analysis, we identified a new monolayer B2O and systematically investigated its fundamental mechanical and electronic properties, especially under strain. Due to the complicated puckered hinge structure of monolayer B2O, it possesses an intrinsic negative Poisson's ratio of -0.021. Moreover, we found that the superconducting state of monolayer B2O can be improved, where strain plays an effective role in regulating the properties of the 2D material. The current results elucidate the structure and corresponding properties of monolayer B2O, which may stimulate related fundamental research and potential nanoscale applications.

Theoretical investigation of the valence states in Au via the Au-F compounds under high pressure.

In addition to the known Au3+ and Au5+, it has recently been shown that Au is likely to possess unusual valence states in compressed Au-F compounds. However, our simulations reveal that polymeric ground-state AuF4 shows an unexpected 6-fold coordination rather than a 4-fold one, indicating that more complete comprehending on the anomalous Au4+ is highly required. To fully understand the nature and origin of anomalous valence states in Au, we have extensively investigated the ground-state structures of Au-F compounds at high pressures using quantum mechanical computational methods. As a consequence, we identify several previously unreported (stable) AuF2, AuF3 and AuF4 structures. Our results extend the known polymorphism of AuFn compounds and offer a fundamental understanding of the origin of unusual valence states in Au that prevail at high pressure.

Phase transition and superconductivity in ReS2, ReSe2 and ReTe2.

Transition metal dichalcogenides have attracted significant attention due to both fundamental interest and their potential applications. Here, we have systematically explored the crystal structures of ReX2 (X = S, Se, and Te) over the pressure range of 0-300 GPa, employing swarm-intelligence-based structure prediction methodology. Several new structures are found to be stable at high pressures. The calculated enthalpy of formation suggested that all predicted high-pressure structures are stable against decomposition into elemental end-members. Moreover, we found that the simulated X-ray diffraction patterns of ReSe2 are in good agreement with experimental data. Pressure-induced metallization of ReX2 has been revealed from the analysis of its electronic structure. Our electron-phonon coupling calculations indicate ReSe2 and ReTe2 are superconducting phases at high pressures.

Catenation of carbon in LaC2 predicted under high pressure.

Carbon has the capability of forming various bonding states that affect the structures and properties of transition metal carbides. In this work, structural search was performed to explore the structural diversity of LaC2 at pressures of 0.0-30.0 GPa. Five stable structures of LaC2 reveal a variety of carbon structural units ranging from a dimer to bent C3, zigzag C4 and armchair polymer chains. A series of pressure-induced structural transformations are predicted, I4/mmm (i.e. experimental α phase) →C2/c→Pnma→Pmma, which involve the catenation of carbon from a dimer to zigzag C4 units and further to armchair polymer chains. The bent C3 unit appears in a novel Immm structure. This structure is the theoretical ground state of LaC2 under ambient conditions, but is kinetically inaccessible from the experimental α phase. LaC2 becomes thermodynamically metastable relative to La2C3 + diamond above 17.1 GPa, and eventually decomposes into constituent elements above 35.6 GPa. The presented results indicate that catenation of carbon can be realized even in simple inorganic compounds under nonambient conditions.

Cocirculation of three hemagglutinin and two neuraminidase subtypes of avian influenza viruses in Huzhou, China, April 2013: implication for the origin of the novel H7N9 virus.

We detected three avian influenza hemagglutinin (HA) subtypes (H7, H9, and H5) and two neuraminidase (NA) subtypes (N9 and N2), as well as H7N9-related H9N9 reassortant intermediates, cocirculating among poultry in Huzhou, China, during April 2013. The results of our study reveal not only that Huzhou is one of the geographic origins of the novel H7N9 virus but also that cocirculation poses a potential threat to humans in the future.

Immobilization of lead in soil influenced by soluble phosphate and calcium: lead speciation evidence.

We investigated the effect of soluble Ca on the speciation of Pb in phosphate-amended soils. A calcareous soil was amended in sequence with soluble phosphate (0 and 299 mg kg P), calcium nitrate (0, 200, and 400 mg kg Ca), and/or lead nitrate (0 and 1000 mg kg Pb) and incubated for 50 d. Extractable Ca was relatively similar across all samples, with a minor reduction in Ca release for treatments amended with P possibly from the formation of Ca-phosphate minerals. Olsen-P extractability from P-added treatments was highest in the non-Pb-amended soils and was about 40% lower when Pb was added as a result of Pb-phosphate formation. In the absence of P, diethylene triamine pentaacetic acid (DTPA)-Pb extractability increased with increasing Ca amendment; however, in the P-amended treatments, DTPA-Pb decreased with increasing Ca addition. X-ray absorption spectroscopy results of the Pb spiked soils indicate that adsorbed Pb is the primary phase (up to 92%) in non-P-amended soils with minor distribution to hydrocerussite and Pb-phosphate phases. In the P-amended treatments, Pb speciation shifted to Pb-phosphate [chloropyromorphite and Pb(PO)] (42-48%) and adsorbed Pb (44-50%). As Ca concentration increased in the P-amended soils, Pb-phosphate speciation moved from combined chloropyromorphite and Pb(PO) (0 mg kg Ca) to exclusively chloropyromorphite. The study demonstrates that soluble Ca enhances Pb immobilization with P amendments.

Analysis of data from two influenza surveillance hospitals in Zhejiang province, China, for the period 2018-2022.

PURPOSE: To assess the epidemiology of seasonal influenza in Huzhou City, Zhejiang Province, China, during 2018-2022 and provide insights for influenza prevention. METHODS: Following the National Influenza Surveillance Program, we conducted pathogen surveillance by randomly sampling throat swabs from cases with influenza-like illness (ILI) at two sentinel hospitals. RESULTS: From 2018 to 2022, a total of 3,813,471 cases were treated at two hospitals in Huzhou, China. Among them, there were 112,385 cases of Influenza-Like Illness (ILI), accounting for 2.95% of the total number of cases. A total of 11,686 ILI throat swab samples were tested for influenza viruses, with 1,602 cases testing positive for influenza virus nucleic acid, resulting in a positivity rate of 13.71%. Among the positive strains, there were 677 strains of A(H3N2) virus, 301 strains of A(H1N1) virus, 570 strains of B/Victoria virus, and 54 strains of B/Yamagata virus. The ILI percentage (ILI%) and influenza nucleic acid positivity rate showed winter-spring peaks in the years 2018, 2019, 2021, and 2022, with the peaks concentrated in January and February. Additionally, a small peak was observed in August 2022 during the summer season. No peak was observed during the winter-spring season of 2020. The highest proportion of ILI cases was observed in children aged 0-4 years, followed by school-age children aged 5-14 years. There was a positive correlation between ILI% and influenza virus nucleic acid positivity rate (r = 0.60, p < 0.05). CONCLUSIONS: The influenza outbreak in Huzhou from 2020 to 2022 was to some extent influenced by the COVID-19 pandemic and public health measures. After the conclusion of the COVID-19 pandemic, the influenza outbreak in Huzhou may become more severe. Therefore, it is crucial to promptly assess the influenza outbreak trends based on the ILI% and the positivity rate of influenza virus nucleic acid tests.

Seroepidemiology of pertussis in Huzhou: A population-based, cross-sectional study.

PURPOSE: The resurgence of pertussis has occurred around the world. However, the epidemiological profiles of pertussis cannot be well understood by current diseases surveillance. This study was designed to understand the seroepidemiological characteristics of pertussis infection in the general population of Huzhou City, evaluate the prevalence infection of pertussis in the population, and offer insights to inform adjustments in pertussis prevention and control strategies. METHODS: From September to October 2023, a cross-sectional serosurvey was conducted in Huzhou City, involving 1015 permanent residents. Serum samples were collected from the study subjects, and pertussis toxin IgG antibodies (Anti-PT-IgG) were quantitatively measured using enzyme-linked immunosorbent assay (ELISA). The analysis included the geometric mean concentration (GMC) of Anti-PT-IgG, rates of GMC≥40IU/mL, ≥100IU/mL, and <5IU/mL. Stratified comparisons were made based on age, vaccination history, and human categories. RESULTS: Among the 1015 surveyed individuals, the geometric mean concentration (GMC) of Anti-PT-IgG was 10.52 (95% CI: 9.96-11.11) IU/mL, with a recent infection rate of 1.58%, a serum positivity rate of 11.43%, and a proportion with <5IU/mL of 40.49%. Among 357 children with clear vaccination history, susceptibility decreased with an increasing number of vaccine doses (Z = -6.793, P < 0.001). The concentration of Anti-PT-IgG exhibited a significant post-vaccination decline over time (Z = -5.143, P < 0.001). In women of childbearing age, the GMC of Anti-PT-IgG was 7.71 (95% CI: 6.90-8.62) IU/mL, with no significant difference in susceptibility among different age groups (χ2 = 0.545, P = 0.909). The annual pertussis infection rate in individuals aged ≥3 years was 9321 (95%CI: 3336-16039) per 100,000, with peak infection rates in the 20-29, 40-49, and 5-9 age groups at 34363 (95%CI: 6327-66918) per 100,000, 22307.72 (95%CI: 1380-47442) per 100,000, and 18020(95%CI: 1093-37266) per 100,000, respectively. CONCLUSIONS: In 2023, the actual pertussis infection rate in the population of Huzhou City was relatively high. Vaccine-induced antibodies exhibit a rapid decay, and the estimated serum infection rate increases rapidly from post-school age, peaking in the 20-29 age group. It is recommended to enhance pertussis monitoring in adolescents and adults and refine vaccine immunization strategies.

Clinical studies on the electric automatic massage therapy for recovery of acute sports fatigue.

BACKGROUND: Acute sports fatigue impairs athletes' performance and causes other health issues; therefore, an effective method of relieving acute sports fatigue is being researched. OBJECTIVE: The present study was envisaged to evaluate the effect of electric auto-massage therapy and proprioceptive neuromuscular facilitated (PNF) stretching method on the recovery of acute exercise fatigue using the heart rate variability-based multi-physiological index and RPE scale, and to explore the underlying principle and mechanism. METHOD: Sixty volunteers were divided into the stretching group, massage group and control group (20 subjects each) using the complete randomization method. The massage group chose the kneading, pressing, tapping and patting techniques using the intelligent massage chair to intervene on the volunteers, the stretching group chose the PNF stretching method to intervene on the volunteers, while the control group did not adopt any of these techniques. The Rating Of Perceived Exertion (RPE) score, heart rate (HR), grip strength, skin electrical activity, heart rate variability (HRV) and blood oxygen saturation (SpO2) of the three groups were recorded before and after the intervention. RESULTS: Before the intervention, there was no statistically significant difference between the values of heart rate variability (HRV) in the three groups (P> 0.05), while after the intervention, there was a statistically significant difference between the values of heart rate variability - low frequency/high frequency (HRV (LF/HF)) and HRV (HF) in the three groups as: HRV (HF): ηH2= 0.10; P= 0.022; HRV (LF/HF): ηH2= 0.44; P= 0.001. The results indicated that the different intervention methods presented substantial effects on the values of HRV (HF) and HRV (LF/HF) in the volunteers. The HRV (HF) values of massage group, stretching group and control group were compared, and the difference between the massage group and control group was statistically significant (P= 0.019). Further, the HRV (HF) values of massage group rose more significantly than control group after the intervention, and the difference between HRV (HF) values of massage group and stretching group was not statistically significant. When comparing the HRV (LF/HF) values of massage group, stretching group and control group, the differences between the massage group and stretching group and control group were statistically significant (P= 0.001, P< 0.05), and it was observed that the HRV (LF/HF) values of massage group decreased more significantly than those of stretching group and control group after the intervention. The difference in HRV (LF) values between the three groups after the intervention was not statistically significant (P> 0.05). CONCLUSION: 1. It was observed that the electric automatic massage therapy played a vital role in the rapid relief of exercise fatigue by soothing and regulating the human phototropic system, reducing vagal tone, and accelerating the excretion of metabolites; while PNF stretching relieved the exercise fatigue by providing physical and verbal communication to transfer the perception of fatigue, and by promoting the excretion of metabolites through muscle isometric contraction. 2. The effect of electric auto-massage therapy was marginally stronger than the commonly used PNF stretching exercise method.