[Metagenomic next-generation sequencing-based retrospective investigation of the drug resistance sites of mycoplasma pneumoniae in children].

Objective: To analyze the drug-resistant gene loci of Mycoplasma pneumoniae (MP) using metagenomic next-generation sequencing (mNGS). Methods: From November 2022 to October 2023, 697 clinical samples (including sputum, alveolar lavage fluid and blood) of 686 children with Mycoplasma pneumoniae positive detected by mNGS were retrospectively analyzed. Samples were divided into intensive care unit (ICU) group and non-ICU group, Chi-square test was used to compare groups, and Mann-Kendall trend test was used to analyze the change trend of the detection rate of drug resistance gene loci over time. Results: Of the 697 samples, 164 were from the ICU group and 533 were from the non-ICU group. The detection rate of Mycoplasma pneumoniae resistance gene was 44.3% (309/697), and all detected drug-resistant gene loci of MP were A2063G. The detection rate of Mycoplasma pneumoniae in ICU group was 50.0% (82/164), and the detection rates of Mycoplasma pneumoniae resistance gene loci in sputum, alveolus lavage fluid and blood samples were 75.0% (18/24) and 48.4% (62/128), respectively. The detection rate in sputum was higher than alveolus lavage fluid samples (χ2=5.72,P=0.017). The detection rate of Mycoplasma pneumoniae in non-ICU group was 42.6% (227/533), the detection rate of Mycoplasma pneumoniae resistance gene loci in sputum and alveolar lavage fluid was 40.0% (16/40), 44.3% (201/454), and no detection rate in blood samples (0/12). There was no significant difference in the detection rate of alveolar lavage fluid and sputum (χ2=0.27, P=0.602). From November 2022 to October 2023, the detection rate of submitted samples showed an increasing trend month by month (overall: Z=3.99, ICU inspection group: Z=2.93, non-ICU group: Z=3.01, all P<0.01). Among the bacteria commonly detected with Mycoplasma pneumoniae, Streptococcus pneumoniae accounted for the highest proportion, the detection rate was 15.5% (108/697), and Epstein-Barr virus accounted for the highest proportion of 17.6% (123/697). Conclusions: From November 2022 to October 2023, the detection rate of Mycoplasma pneumoniae drug resistance gene loci showed an increasing trend. The detection rate of drug resistance gene loci in sputum samples of ICU group was higher than alveolus lavage fluid. No new drug resistance site were detected.

Two-Dimensional Moiré Polaronic Electron Crystals.

Two-dimensional moiré materials have emerged as the most versatile platform for realizing quantum phases of electrons. Here, we explore the stability origins of correlated states in WSe_{2}/WS_{2} moiré superlattices. We find that ultrafast electronic excitation leads to partial melting of the Mott states on timescales 5 times longer than predictions from the charge hopping integrals and that the melting rates are thermally activated, with activation energies of 18±3 and 13±2 meV for the one- and two-hole Mott states, respectively, suggesting significant electron-phonon coupling. A density functional theory calculation of the one-hole Mott state confirms polaron formation and yields a hole-polaron binding energy of 16 meV. These findings reveal a close interplay of electron-electron and electron-phonon interactions in stabilizing the polaronic Mott insulators at transition metal dichalcogenide moiré interfaces.

Optical spin hall effect in exciton-polariton condensates in lead halide perovskite microcavities.

An exciton-polariton condensate is a hybrid light-matter state in the quantum fluid phase. The photonic component endows it with characters of spin, as represented by circular polarization. Spin-polarization can form stochastically for quasi-equilibrium exciton-polariton condensates at parallel momentum vector k|| ∼ 0 from bifurcation or deterministically for propagating condensates at k|| > 0 from the optical spin-Hall effect (OSHE). Here, we report deterministic spin-polarization in exciton-polariton condensates at k|| ∼ 0 in microcavities containing methylammonium lead bromide perovskite (CH3NH3PbBr3) single crystals under non-resonant and linearly polarized excitation. We observe two energetically split condensates with opposite circular polarizations and attribute this observation to the presence of strong birefringence, which introduces a large OSHE at k|| ∼ 0 and pins the condensates in a particular spin state. Such spin-polarized exciton-polariton condensates may serve not only as circularly polarized laser sources but also as effective alternatives to ultracold atom Bose-Einstein condensates in quantum simulators of many-body spin-orbit coupling processes.

[Single non-blood-related umbilical cord blood transplantation using a reduced-intensity conditioning regimen for the treatment of severe aplastic anemia].

Objective: To evaluated the clinical efficacy of a reduced-intensity preconditioning regimen for single non-blood-related umbilical cord blood transplantation (sUCBT) in the treatment of severe aplastic anemia (SAA) . Methods: The clinical data of 63 patients with SAA who underwent sUCBT from January 2021 to July 2023 at the Department of Hematology of the First Affiliated Hospital of USTC were retrospectively analyzed. Fifty-two patients received total body irradiation/total bone marrow irradiation (TMI) combined with fludarabine or a cyclophosphamide- conditioning regimen (non-rATG group) , while 11 patients received rabbit anti-human thymocyte immunoglobulin (rATG) combined with TMI, fludarabine, or the cyclophosphamide-conditioning regimen (rATG group) . All patients received cyclosporine A and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Complications post-transplantation and long-term survival were compared between the two groups. Results: The baseline parameters were balanced between the two groups (P>0.05) . In the rATG group, all patients achieved stem cell engraftment, and in the non-rATG group, five patients had primary graft failure. There was no significant difference in the cumulative incidence of neutrophil engraftment at 42 days after transplantation or platelet engraftment at 60 days between the two groups. The incidence of grade Ⅱ-Ⅳ acute GVHD in the rATG group was significantly lower than in the non-rATG group (10.0% vs. 46.2% , P=0.032) , and the differences in the cumulative incidences of grade Ⅲ/Ⅳ acute GVHD and 1-year chronic GVHD were not statistically significant (P=0.367 and P=0.053, respectively) . There were no significant differences in the incidences of pre-engraftment syndrome, bacterial bloodstream infections, cytomegalovirus viremia, or hemorrhagic cystitis between the two groups (P>0.05 for all) . The median follow-up time for surviving patients was 536 (61-993) days, and the 1-year transplantation related mortality (TRM) of all patients after transplantation was 13.0% (95% CI 6.7% -24.3% ) . Among the patients in the non-rATG and rATG groups, 15.5% (95% CI 8.1% -28.6% ) and 0% (P=0.189) , respectively, had mutations. The 1-year overall survival (OS) rate of all patients after transplantation was 87.0% (95% CI 75.7% -93.3% ) . The 1-year OS rates in the rATG group and non-rATG group after transplantation were 100% and 84.5% , respectively (95% CI 71.4% -91.9% ) (P=0.198) . Conclusion: The preliminary results of sUCBT with a low-dose irradiation-based reduced-intensity conditioning regimen with fludarabine/cyclophosphamide for the treatment of patients with SAA showed good efficacy. Early application of low-dose rATG can reduce the incidence of acute GVHD after transplantation without increasing the risk of implantation failure or infection.

The value of quantitative contrast-enhanced ultrasonography analysis in evaluating central retinal artery microcirculation in patients with diabetes mellitus: comparison with colour Doppler imaging.

AIM: To compare the efficacy of quantitative contrast-enhanced ultrasonography (CEUS) analysis and colour Doppler ultrasound (CDU) in evaluating central retinal artery (CRA) microcirculation in patients with diabetes mellitus (DM). MATERIALS AND METHODS: In this prospective study, a total of 55 patients (98 eyes) with DM were enrolled as the study group. They were compared to 46 age-matched healthy volunteers (92 eyes) who were selected as the control group. Each patient underwent CDU and subsequent CEUS examination. CDU and quantitative CEUS parameters were evaluated. The diagnostic efficiency of the diagnostic performance of CEUS and CDU was evaluated and compared, and the scale thresholds of predictive indicators for the diagnosis of proliferative diabetic retinopathy (PDR) were evaluated using receiver operating characteristics (ROC) curve analyses. RESULTS: Group pairwise comparisons showed that the end diastolic velocity (EDV) and arrival time (AT) of CRA were significant predictors for PDR by CDU and by quantitative CEUS analysis, respectively (all p<0.05). The ROC curve analysis showed that the area under the curve value of AT was significantly higher than that of EDV (0.875 versus 0.634, p=0.0002). Accordingly, an AT cut-off value of 1.07 seconds resulted a sensitivity of 90.62 % and a specificity of 79.31 %. CONCLUSION: Quantitative CEUS analysis can improve the accuracy of clinical staging of diabetic retinopathy for the patients with DM, and the AT showed the best diagnostic efficiency.

Hyperbolic exciton polaritons in a van der Waals magnet.

Exciton polaritons are quasiparticles of photons coupled strongly to bound electron-hole pairs, manifesting as an anti-crossing light dispersion near an exciton resonance. Highly anisotropic semiconductors with opposite-signed permittivities along different crystal axes are predicted to host exotic modes inside the anti-crossing called hyperbolic exciton polaritons (HEPs), which confine light subdiffractionally with enhanced density of states. Here, we show observational evidence of steady-state HEPs in the van der Waals magnet chromium sulfide bromide (CrSBr) using a cryogenic near-infrared near-field microscope. At low temperatures, in the magnetically-ordered state, anisotropic exciton resonances sharpen, driving the permittivity negative along one crystal axis and enabling HEP propagation. We characterize HEP momentum and losses in CrSBr, also demonstrating coupling to excitonic sidebands and enhancement by magnetic order: which boosts exciton spectral weight via wavefunction delocalization. Our findings open new pathways to nanoscale manipulation of excitons and light, including routes to magnetic, nonlocal, and quantum polaritonics.

[Report content and prenatal diagnosis of non-invasive prenatal testing for sex chromosome aneuploidy].

Objective: To analyze the report content, the methods and results of prenatal diagnosis of high risk of sex chromosome aneuploidy (SCA) in non-invasive prenatal testing (NIPT). Methods: A total of 227 single pregnancy pregnant women who received genetic counseling and invasive prenatal diagnosis at Drum Tower Hospital Affiliated to the Medical School of Nanjing University from January 2015 to April 2022 due to the high risk of SCA suggested by NIPT were collected. The methods and results of prenatal diagnosis were retrospectively analyzed, and the results of chromosome karyotype analysis and chromosome microarray analysis (CMA) were compared. The relationship between NIPT screening and invasive prenatal diagnosis was analyzed. Results: (1) Prenatal diagnosis methods for 277 SCA high risk pregnant women included 73 cases of karyotyping, 41 cases of CMA and 163 cases of karyotyping combined with CMA, of which one case conducted amniocentesis secondly for further fluorescence in situ hybridization (FISH) testing. Results of invasive prenatal diagnosis were normal in 166 cases (59.9%, 166/277), and the abnormal results including one case of 45,X (0.4%, 1/277), 18 cases of 47,XXX (6.5%, 18/277), 36 cases of 47,XXY (13.0%, 36/277), 20 cases of 47,XYY (7.2%, 20/277), 1 case of 48,XXXX (0.4%, 1/277), 20 cases of mosaic SCA (7.2%, 20/277), 5 cases of sex chromosome structural abnormality or large segment abnormality (1.8%, 5/277), and 10 cases of other abnormalities [3.6%, 10/277; including 9 cases of copy number variation (CNV) and 1 case of balanced translocation]. Positive predictive value (PPV) for SCA screening by NIPT was 34.7% (96/277). (2) Among the 163 cases tested by karyotyping combined with CMA, 11 cases (6.7%, 11/163) showed inconsistent results by both methods, including 5 cases of mosaic SCA, 1 case of additional balanced translocation detected by karyotyping and 5 cases of additional CNV detected by CMA. (3) NIPT screening reports included 149 cases of "sex chromosome aneuploidy"(53.8%, 149/277), 54 cases of "number of sex chromosome increased" (19.5%, 54/277), and 74 cases of "number of sex chromosome or X chromosome decreased" (26.7%, 74/277). The PPV of "number of sex chromosome increased" and "number of sex chromosome or X chromosome decreased" were 72.2% (39/54) and 18.9% (14/74), respectively, and the difference was statistically significant (χ2=34.56, P<0.01). Conclusions: NIPT could be served as an important prenatal screening technique of SCA, especially for trisomy and mosaicism, but the PPV is comparatively low. More information of NIPT such as the specific SCA or maternal SCA might help improving the confidence of genetic counseling and thus guide clinic management. Multi technology platforms including karyotyping, CMA and FISH could be considered in the diagnosis of high risk of SCA by NIPT.

[Analysis of factors influencing AIDS-related deaths among HIV-infected people in Shandong Province, 2017-2021].

Objective: To explore the influencing factors of AIDS-related deaths among HIV-infected patients in Shandong Province, to help reduce the risk of death and prolong survival time. Methods: The study population was HIV-infected patients in Shandong Province from 2017-2021, and Cox proportional hazards regression model was used to analyze the influencing factors of AIDS-related deaths and deaths within one year of confirmation. Results: Among 14 700 HIV- infected patients reported in Shandong Province in 2017-2021, 351 AIDS-related deaths occurred, accounting for 2.4% (351/14 700). The results of multifactorial Cox proportional hazards regression model analysis showed that the risk factors for AIDS-related deaths among HIV-infected patients included education level of junior high school, high school, and secondary school (aHR=1.37, 95%CI:1.01-1.84), sample source from healthcare institutions (aHR=1.61, 95%CI:1.22-2.12), duration of disease in AIDS stage (aHR=9.86,95%CI:6.86-14.19), baseline CD4+T lymphocytes (CD4) undetected (aHR=3.93, 95%CI:2.69-5.75), duration of antiviral treatment (ART) <6 months (aHR=3.46, 95%CI:2.42-4.93) and no ART (aHR=1.45, 95%CI:1.02-2.07), final CD4 <200 cells/µl (aHR=3.51, 95%CI:2.18-5.65) and final CD4 undetected (aHR=10.58, 95%CI:6.15-18.19), and final viral load (VL) values of 50-999 copies/ml,≥1 000 copies/ml and undetected (aHR=2.59, 95%CI:1.07-6.26; aHR=9.50, 95%CI:5.60-16.12; aHR=15.33, 95%CI:8.91-26.36). Factors with higher risk of AIDS-related deaths within one year of confirmation of HIV-infected patients included samples originating from healthcare facilities (aHR=1.68, 95%CI: 1.19-2.36), AIDS stage of disease (aHR=10.60, 95%CI:7.13-15.75), baseline CD4 undetected (aHR=3.71, 95%CI:2.34-5.90), duration of ART <6 months (aHR=4.30, 95%CI:2.85-6.49) and no ART (aHR=2.05, 95%CI:1.35-3.13), final CD4 <200 cells/µl (aHR=5.45,95%CI:2.04-14.60) and final CD4 undetected (aHR=20.95, 95%CI: 7.69- 57.04), and final VL values of 50-999 copies/ml, ≥1 000 copies/ml and undetected (aHR=15.21, 95%CI: 2.54-91.21; aHR=42.93, 95%CI:9.64-191.20; aHR=61.35, 95%CI:13.85-271.77). Conclusions: Expanding the coverage of testing, promoting early detection and treatment, strengthening regular follow-up and the test of HIV-infected patients, grasping the progress of the disease to provide accurate management and treatment are important for reducing the disease mortality rate and prolonging the survival time of HIV-infected patients.

[Analysis of characteristics of types of primary sexual partners and related factors of not being tested for HIV among men who have sex with men].

Objective: To compare the characteristics of MSM with different types of primary sexual partners and to analyze the factors associated with MSM not being tested for HIV in the last six months. Methods: MSM were recruited in nine cities of Shandong Province from April to July 2021, and face-to-face questionnaires were conducted to collect information on sociodemographic characteristics, high-risk behaviors, and HIV testing of MSM. Blood samples were taken for serological tests of HIV and syphilis antibodies. Results: A total of 3 008 men who had anal sex with men in the last six months were divided into three groups according to the type of primary sexual partner in the last six months: the fixed sexual partner group (36.83%, 1 108/3 008), the commercial sexual partner group (3.06%, 92/3 008), and casual sexual partner group (60.11%, 1 808/3 008). There were statistically significant differences in the distribution of age, local residence time, education level, the primary place to find male sexual partners, use of new-type drugs in the last six months, consistent condom use every time during same-sex anal sex in the last six months, group sex in the last six months, no HIV testing in the last six months, having had a sexually transmitted disease in the last year, receiving peer education in the last year, and frequency of syphilis testing in the last year among different groups (P<0.05). Multivariable logistic regression analysis showed that related factors of not being tested for HIV in the last six months in MSM were those aged less than 30 years old (aOR=1.39, 95%CI: 1.06-1.83), married/cohabiting (aOR=1.74, 95%CI: 1.39-2.16), high school education or less (aOR=1.39, 95%CI: 1.15-1.67), had not used new-type drugs in the last six months (aOR=2.27, 95%CI: 1.89-2.71), had not received peer education in the last year (aOR=1.59, 95%CI: 1.28-1.98), had never been tested for syphilis (aOR=11.30, 95%CI: 8.15-15.66), had not been tested in the last year but had been previously tested for syphilis (aOR=5.65, 95%CI: 4.19-7.62), the type of primary sexual partner in the last six months being a commercial sexual partner (aOR=1.80, 95%CI: 1.01-3.20), and the type of primary sexual partner in the last six months being a casual sexual partner (aOR=1.50, 95%CI: 1.26-1.80). Conclusions: The characteristics of MSM with different types of primary sexual partners are different, and the proportion of HIV testing still needs to be improved. In the future, we should make full use of the Internet and peer education to expand the coverage of HIV testing for MSM, targeting the characteristics of MSM with different types of primary sexual partners.

Nonlinear terahertz control of the lead halide perovskite lattice.

Lead halide perovskites (LHPs) have emerged as an excellent class of semiconductors for next-generation solar cells and optoelectronic devices. Tailoring physical properties by fine-tuning the lattice structures has been explored in these materials by chemical composition or morphology. Nevertheless, its dynamic counterpart, phonon-driven ultrafast material control, as contemporarily harnessed for oxide perovskites, has not yet been established. Here, we use intense THz electric fields to obtain direct lattice control via nonlinear excitation of coherent octahedral twist modes in hybrid CH3NH3PbBr3 and all-inorganic CsPbBr3 perovskites. These Raman-active phonons at 0.9 to 1.3 THz are found to govern the ultrafast THz-induced Kerr effect in the low-temperature orthorhombic phase and thus dominate the phonon-modulated polarizability with potential implications for dynamic charge carrier screening beyond the Fröhlich polaron. Our work opens the door to selective control of LHP's vibrational degrees of freedom governing phase transitions and dynamic disorder.

Do patients with bipolar disorders have an increased risk of myocardial infarction? A systematic review and meta-analysis.

OBJECTIVE: Research shows that patients with bipolar disorders (BD) may have an altered risk of cardiovascular diseases; however, the association between the two is not clear. In this study, we reviewed evidence on the association between BD and subsequent risk of myocardial infarction (MI). MATERIALS AND METHODS: Studies published on PubMed, Embase, Scopus, CENTRAL, and Web of Science were identified up to 30th August 2023. Random-effects meta-analysis was done to calculate the pooled odds ratio (OR). RESULTS: A total of six studies with 19,862,894 individuals were included. Of these, 46,627 were diagnosed with BD (0.23%). The median follow-up of the studies varied from 7.6 to 20 years. Meta-analysis of all six studies showed that BD patients do not have a higher risk of MI as compared to the general population (OR: 1.36, 95% CI: 0.99, 1.86). The overall analysis had substantial heterogeneity with I2=86%. No publication bias was noted among the studies. Results did not change during sensitivity analysis. CONCLUSIONS: Current evidence fails to show an association between BD and subsequent risk of MI. The high heterogeneity in the meta-analysis and lack of adjustment of all important confounders are significant limitations that need to be overcome by future studies.

[Characteristics and depressive symptoms among self-reported HIV infection through heterosexual transmission men who have sex with men].

Objective: To understand the characteristics and depressive status of men who have sex with men (MSM) who self-reported HIV infection through heterosexual transmission and to provide evidence for personalized management of HIV infected people. Methods: A cross-sectional survey was carried out in Shandong province from September to December in 2019. Male HIV patients aged ≥15 years who self-reported HIV infection through heterosexual transmission were selected to verify the route of infection by one-to-one interview in Ji'nan, Qingdao, Weifang and Linyi cities of Shangdong province. According to the 1∶1 ratio, local HIV patients with age difference ≤3 years who self-reported MSM were selected as controls. A questionnaire survey was conducted, including data on demographic characteristics, behavior status, CES-D and PSSS. The related factors of the depressive symptoms and characteristics were analyzed. Results: A total of 373 male HIV patients were interviewed, and 39.7%(148/373) were confirmed as MSM after reexamination. The interviewers were: aged (40.3±12.0) years old, 41.9% (62/148) married/cohabiting. 27.0% (40/148) had been tested before HIV diagnosis, 71.6% (106/148) had homosexual partners ≥2 and 55.4% (82/148) had depressive symptom. Multivariate analysis showed that the MSM without HIV testings before diagnosis, had homosexual partners ≥2 before diagnosis, had first homosexual behavior at the age >30 years old and with depressive symptoms were more likely to conceal the true infection route. The incidence of depression among MSM who self-reported HIV infection through heterosexual transmission was related to physical health status social support and occupational stability. Conclusions: Some male HIV persons self-reported as being heterosexually transmitted were really transmitted through homosexual behavior. There were high-risk behaviors such as multiple partners and intersex among this group, and with high incidence of depression. It is necessary to encourage the reexamination program during follow-up and target on psychological and behavioral interventions, continuously.

[Analysis of the usage of post-exposure prophylaxis and related factors among men who have sex with men].

A survey was conduct to analyze the usage situation of post-exposure prophylaxis(PEP) and related factors among men who have sex with men(MSM) in 6 cities of Shandong Province. Total of 2 620 subjects, the use ratio was 2.98% (78/2 620). Compared with age≤24 years,monthly income<5 000 yuan,non-commercial sex, non-DU,non-STD,role for being insert in the anal intercourse,MSM was more likely to use PEP with age≥45 years(OR=3.87, 95%CI:1.12-13.36),monthly income≥5 000 yuan(OR=1.87, 95%CI:1.07-3.28),commercial sex (OR=3.13, 95%CI:1.56-6.28), drug users (DUs) (OR=4.63, 95%CI:2.51-8.52),STD patient (OR=2.35,95%CI:1.05-5.27),the mixed sex role group(OR=2.25,95%CI:1.10-4.62).

Disorder of excitons and trions in monolayer MoSe2.

The optical spectra of transition metal dichalcogenide monolayers are dominated by excitons and trions. Here, we establish the dependence of these optical transitions on the disorder from hyperspectral imaging of h-BN encapsulated monolayer MoSe2. While both exciton and trion energies vary spatially, these two quantities are almost perfectly correlated, with spatial variation in the trion binding energy of only ∼0.18 meV. In contrast, variation in the energy splitting between the two lowest energy exciton states is one order of magnitude larger at ∼1.7 meV. Statistical analysis and theoretical modeling reveal that disorder results from dielectric and bandgap fluctuations, not electrostatic fluctuations. Our results shed light on disorder in high quality TMDC monolayers, its impact on optical transitions, and the many-body nature of excitons and trions.

Characteristics of vertical drop jump to screen the anterior cruciate ligament injury.

OBJECTIVE: To clarify the characteristics of vertical drop jump (VDJ) for screening athletes at high risk of ACL injury by comparing the kinematic, kinetic and electromyographic variables of different VDJ. SUBJECTS AND METHODS: Thirty male soccer players were recruited to measure parameters of knee kinematics, kinetics, and surface electromyograph during VDJ in four kinds of movements measured (the distance between the take-off feet is 5 cm or 30 cm, and the distance between the landing feet is 5 cm or 30 cm) using the Vicon motion capture system, Kistler3-D dynamometer, and Noraxon surface electromyograph test system. RESULTS: The peak knee abduction moment was significantly greater for landing feet distance of 30 cm compared to landing feet distance of 5 cm, regardless of whether the distance between take-off feet was 5 cm (0.58 vs. 0.44) or 30 cm (0.61 vs. 0.40); regardless of whether the distance between landing feet was 5 cm (22.78 vs. 20.45) or 30 cm (24.32 vs. 21.87), the peak vertical Ground Reaction Force was significantly increased for the take-off feet distance was 5 cm compared to take-off feet of 30 cm. CONCLUSIONS: In the test of VDJ, athletes will adopt different landing strategies for different movement instructions, and the VDJ with the distance of 5 cm between the take-off feet and the distance of 30 cm between the landing feet may be the better maneuver to screen for risk of ACL injury.

Simultaneous macroscale and microscale wave-ion interaction in near-earth space plasmas.

Identifying how energy transfer proceeds from macroscales down to microscales in collisionless plasmas is at the forefront of astrophysics and space physics. It provides information on the evolution of involved plasma systems and the generation of high-energy particles in the universe. Here we report two cross-scale energy-transfer events observed by NASA's Magnetospheric Multiscale spacecraft in Earth's magnetosphere. In these events, hot ions simultaneously undergo interactions with macroscale (~[Formula: see text] km) ultra-low-frequency waves and microscale ([Formula: see text] km) electromagnetic-ion-cyclotron (EMIC) waves. The cross-scale interactions cause energy to directly transfer from macroscales to microscales, and finally dissipate at microscales via EMIC-wave-induced ion energization. The direct measurements of the energy transfer rate in the second event confirm the efficiency of this cross-scale transfer process, whose timescale is estimated to be roughly ten EMIC-wave periods about (1 min). Therefore, these observations experimentally demonstrate that simultaneous macroscale and microscale wave-ion interactions provide an efficient mechanism for cross-scale energy transfer and plasma energization in astrophysical and space plasmas.

Phonon signatures for polaron formation in an anharmonic semiconductor.

Mechanistic studies on lead halide perovskites (LHPs) in recent years have suggested charge carrier screening as partially responsible for long carrier diffusion lengths and lifetimes that are key to superior optoelectronic properties. These findings have led to the ferroelectric large polaron proposal, which attributes efficient charge carrier screening to the extended ordering of dipoles from symmetry-breaking unit cells that undergo local structural distortion and break inversion symmetry. It remains an open question whether this proposal applies in general to semiconductors with LHP-like anharmonic and dynamically disordered phonons. Here, we study electron-phonon coupling in Bi2O2Se, a semiconductor which bears resemblance to LHPs in ionic bonding, spin-orbit coupling, band transport with long carrier diffusion lengths and lifetimes, and phonon disorder as revealed by temperature-dependent Raman spectroscopy. Using coherent phonon spectroscopy, we show the strong coupling of an anharmonic phonon mode at 1.50 THz to photo-excited charge carriers, while the Raman excitation of this mode is symmetry-forbidden in the ground-state. Density functional theory calculations show that this mode, originating from the A1g phonon of out-of-plane Bi/Se motion, gains oscillator strength from symmetry-lowering in polaron formation. Specifically, lattice distortion upon ultrafast charge localization results in extended ordering of symmetry-breaking unit cells and a planar polaron wavefunction, namely a two-dimensional polaron in a three-dimensional lattice. This study provides experimental and theoretical insights into charge interaction with anharmonic phonons in Bi2O2Se and suggests ferroelectric polaron formation may be a general principle for efficient charge carrier screening and for defect-tolerant semiconductors.

Clinical effect of unilateral balloon infusion of low dose bone cement in PKP for osteoporotic thoracolumbar compression fractures in the elderly.

OBJECTIVE: The study was undertaken to determine the clinical effectiveness of percutaneous kyphoplasty (PKP) with unilateral balloon infusion of low dose of bone cement for treatment of osteoporotic vertebral compression fractures (OVCFs) in the elderly. PATIENTS AND METHODS: A retrospective study was carried out. A total of 36 patients with OVCFs treated by PKP from August 2019 and August 2020 were included. Patients were divided into two groups according to the amount of bone cement infused into the vertebral body. The amount of cement in conventional-dose group was 3.5-6.0 mL and the amount of cement in small-dose group was 1.8-3.0 mL. Pain relief before and after the operation were evaluated, and the leakage of bone cement in the two groups was also observed. RESULTS: Two groups of patients have obtained a good clinical efficacy. Pain has significant differences before and after the operation (p < 0.05). More importantly, compared with conventional-dose group, small-dose group has lower bone cement leakage rate (p < 0.05). CONCLUSIONS: PKP with small-dose bone cement infusion can obtain the same clinical effects of conventional-dose, but the incidence of bone cement leakage is lower and safe.