Interfacial Dehydration Strategy for Chitosan Film Shape Morphing and Its Application.

Shape morphing of biopolymer materials, such as chitosan (CS) films, has great potential for applications in many fields. Traditionally, their responsive behavior has been induced by the differential water swelling through the preparation of multicomponent composites or cross-linking as deformation is not controllable in the absence of these processes. Here, we report an interfacial dehydration strategy to trigger the shape morphing of the monocomponent CS film without cross-linking. The release of water molecules is achieved by spraying the surface with a NaOH solution or organic solvents, which results in the interfacial shrinkage and deformation of the entire film. On the basis of this strategy, a range of CS actuators were developed, such as soft grippers, joint actuators, and a light switch. Combined with the geometry effect, edited deformation was also achieved from the planar CS film. This shape-morphing strategy is expected to enable the application of more biopolymers in a wide range of fields.

High Thermoelectric Performance in Bismuth Telluride via Constructing MoSe2-2D Heterojunction.

Currently, the only thermoelectric (TE) materials commercially available at room temperature are those based on bismuth telluride. However, their widespread application is limited due to their inferior thermoelectric and mechanical properties. In this study, a strategy of growing a rigid second phase of MoSe2 is employed, in situ within the matrix phase to achieve n-type bismuth telluride-based materials with exceptional mechanical and thermoelectric properties. The in situ grown second phase contributes to both the electronic and lattice thermal conductivities. This is primarily attributed to the strong energy filtering effect, as the second phase forms a semi-common lattice interfacial structure with the matrix phase during growth. Furthermore, for composites containing 2 wt% MoSe2, a maximum zT value of 1.24 at 373 K can be achieved. On this basis, 8-pair TE module is fabricated and 1-pair TE module is optimized using a homemade p-type material. The optimized 1-pair TE module generates a maximum output power of 13.6 µW, which is twice that of the 8-pair TE module and four times more than the 8-pair TE module fabricated by commercial material. This work facilitates the development of the TE module by presenting a novel approach to obtaining bismuth telluride-based thermoelectric materials with superior thermoelectric and mechanical properties.

Observation of Higher-Order Nodal-Line Semimetal in Phononic Crystals.

Higher-order topological insulators and semimetals, which generalize the conventional bulk-boundary correspondence, have attracted extensive research interest. Among them, higher-order Weyl semimetals feature twofold linear crossing points in three-dimensional momentum space, 2D Fermi-arc surface states, and 1D hinge states. Higher-order nodal-point semimetals possessing Weyl points or Dirac points have been implemented. However, higher-order nodal-line or nodal-surface semimetals remain to be further explored in experiments in spite of many previous theoretical efforts. In this work, we realize a second-order nodal-line semimetal in 3D phononic crystals. The bulk nodal lines, 2D drumhead surface states guaranteed by Zak phases, and 1D flat hinge states attributed to k_{z}-dependent quadrupole moments are observed in simulations and experiments. Our findings of nondispersive surface and hinge states may promote applications in acoustic sensing and energy harvesting.

Topological Network Modes in a Twisted Moiré Phononic Crystal.

Twisted moiré materials, a new class of layered structures with different twist angles for neighboring layers, are attracting great attention because of the rich intriguing physical phenomena associated with them. Of particular interest are the topological network modes, first proposed in the small angle twisted bilayer graphene under interlayer bias. Here we report the observations of such topological network modes in twisted moiré phononic crystals without requiring the external bias fields. Acoustic topological network modes that can be constructed in a wide range of twist angles are both observed in the domain walls with and without reconstructions, which serve as the analogy of the lattice relaxations in electronic moiré materials. Topological robustness of the topological network modes is observed by introducing valley-preserved defects to the network channel. Furthermore, the network can be reconfigured into two-dimensional patterns with any desired connectivity, offering a unique prototype platform for acoustic applications.

Topological negative refraction of surface acoustic waves in a Weyl phononic crystal.

Reflection and refraction of waves occur at the interface between two different media. These two fundamental interfacial wave phenomena form the basis of fabricating various wave components, such as optical lenses. Classical refraction-now referred to as positive refraction-causes the transmitted wave to appear on the opposite side of the interface normal compared to the incident wave. By contrast, negative refraction results in the transmitted wave emerging on the same side of the interface normal. It has been observed in artificial materials1-5, following its theoretical prediction6, and has stimulated many applications including super-resolution imaging7. In general, reflection is inevitable during the refraction process, but this is often undesirable in designing wave functional devices. Here we report negative refraction of topological surface waves hosted by a Weyl phononic crystal-an acoustic analogue of the recently discovered Weyl semimetals8-12. The interfaces at which this topological negative refraction occurs are one-dimensional edges separating different facets of the crystal. By tailoring the surface terminations of the Weyl phononic crystal, constant-frequency contours of surface acoustic waves can be designed to produce negative refraction at certain interfaces, while positive refraction is realized at different interfaces within the same sample. In contrast to the more familiar behaviour of waves at interfaces, unwanted reflection can be prevented in our crystal, owing to the open nature of the constant-frequency contours, which is a hallmark of the topologically protected  surface states in Weyl crystals8-12.

[Construction of a predictive model for postoperative pain relief after microscopic spermatic cord surgery for spermatic cord pain].

OBJECTIVE: To explore the relevant factors affecting the efficacy of microscopic spermatic cord surgery and build a predictive model for postoperative pain relief. METHODS: A retrospective analysis was conducted on the clinical data of 324 patients with spermatic cord pain who visited the Department of Urology at Peking University People's Hospital between October 2015 and April 2023. This cohort included 212 patients with varicocele-related spermatic cord pain and 112 patients with idiopathic spermatic cord pain. All the patients underwent microsurgical procedures: varicocele-related pain was treated with microsurgical varicocelectomy, and idiopathic pain was treated with microsurgical denervation of the spermatic cord. The patients were categorized into effective and ineffective groups based on whether their pain had decreased by more than 50% six months post-surgery compared with pre-surgery levels. Baseline data were preliminarily screened for clinical indicators using t tests and univariate analysis. Clinical predictor variables [age, duration of pain, diameter of varicocele, patient health questionnaire-9 (PHQ-9) score, generalized anxiety disorder-7 (GAD-7) score] were selected using Lasso regression. A clinical prediction model for effective pain relief following microscopic spermatic cord surgery was constructed using Logistic regression and presented as a nomogram. The model's internal validation was performed using the bootstrap method. Its predictive power and clinical utility were evaluated through the concor-dance index, the area under the receiver operating characteristic curve, and calibration plots. RESULTS: Post-microscopic varicocele ligation, 156 patients (73.58%) experienced significant pain relief, as did 94 patients (83.93%) following microscopic denervation. Independent predictors for postoperative outcomes included age, PHQ-9 score, GAD-7 score, chronic pain duration, and varicocele diameter, differing slightly between varicocele-related and idiopathic pain groups. The models demonstrated excellent predictive ability, with areas under the curve of 0.909 and 0.913 for varicocele and idiopathic groups, respectively, and high concordance indices. CONCLUSION: The postoperative efficacy prediction model based on age, pain duration, PHQ-9 score, GAD-7 score, and varicocele diameter has good predictive ability and clinical applicability, and can be used in clinical practice.

All Cubic-Phase δ-TAGS Thermoelectrics Over the Entire Mid-Temperature Range.

GeTe-based pseudo-binary (GeTe)x (AgSbTe2 )100- x (TAGS-x) is recognized as a promising p-type mid-temperature thermoelectric material with outstanding thermoelectric performance; nevertheless, its intrinsic structural transition and metastable microstructure (due to Ag/Sb/Ge localization) restrict the long-time application of TAGS-x in practical thermoelectric devices. In this work, a series of non-stoichiometric (GeTe)x (Ag1- δ Sb1+ δ Te2+ δ )100- x (x = 85∼50; δ = ≈0.20-0.23), referred to as δ-TAGS-x, with all cubic phase over the entire testing temperature range (300-773 K), is synthesized. Through optimization of crystal symmetry and microstructure, a state-of-the-art ZTmax of 1.86 at 673 K and average ZTavg of 1.43 at ≈323-773 K are realized in δ-TAGS-75 (δ = 0.21), which is the highest value among all reported cubic-phase GeTe-based thermoelectric systems so far. As compared with stoichiometric TAGS-x, the remarkable thermoelectric achieved in cubic δ-TAGS-x can be attributed to the alleviation of highly (electrical and thermal) resistive grain boundary Ag8 GeTe6 phase. Moreover, δ-TAGS-x exhibits much better mechanical properties than stoichiometric TAGS-x, together with the outstanding thermoelectric performance, leading to a robust single-leg thermoelectric module with ηmax of ≈10.2% and Pmax of ≈0.191 W. The finding in this work indicates the great application potential of non-stoichiometric δ-TAGS-x in the field of mid-temperature waste heat harvesting.

Heat tracer-based sap flow methods for tree transpiration measurements: a mini review and bibliometric analysis.

Accurate measurement of plant transpiration is critical to gaining a better understanding of plant water use and exploration of the influence of plants on regional and even global climate. Heat tracer-based sap flow (HTSF) techniques are currently the dominant method to estimate plant transpiration at the individual plant level. However, the majority of current research focuses on specific applications or the evaluation of the method itself, and there is a lack of an overall analysis of HTSF methods. The objectives of this study were: (i) to briefly review the theories and categories of the various HTSF methods, and (ii) to undertake a bibliometric analysis of the use of HTSF methods in measuring plant transpiration. Each HTSF method is described mathematically and their application and pros and cons are briefly discussed. A bibliometric analysis was conducted using 3964 papers published between 1992 and 2020 archived in the Web of Science core collection. The analysis identified publication trends, the most productive authors, organizations, and countries, as well as the most utilized HTSF method (i.e., thermal dissipation) and journals in which these papers were published. In addition, world distribution maps of the use of HTSF methods and tree species measured were drawn based on 741 selected publications with in situ measurements.

Acoustic Higher-Order Weyl Semimetal with Bound Hinge States in the Continuum.

Higher-order topological phases have raised widespread interest in recent years with the occurrence of the topological boundary states of dimension two or more less than that of the system bulk. The higher-order topological states have been verified in gapped phases, in a wide variety of systems, such as photonic and acoustic systems, and recently also observed in gapless semimetal phase, such as Weyl and Dirac phases, in systems alike. The higher-order topology is signaled by the hinge states emerging in the common band gaps of the bulk states and the surface states. In this Letter, we report our first prediction and observation of a new type of hinge states, the bound hinge states in the continuum (BHICs) bulk band, in a higher-order Weyl semimetal implemented in phononic crystal. In contrast to the hinge state in gap, which is characterized by the bulk polarization, the BHIC is identified by the nontrivial surface polarization. The finding of the topological BHICs broadens our insight to the topological states, and may stimulate similar researches in other systems such as electronic, photonic, and cold atoms systems. Our Letter may pave the way toward high-Q acoustic devices in application.

Suspected allergy to titanium after anterior cervical discectomy and fusion using a Zero-P device: a case report.

PURPOSE: Cases of allergy to large surgical implants have been reported. However, few studies have reported allergy to small titanium-containing implants (e.g. Zero-P device). METHODS: We reported the case of a 51-year old male patient who underwent the anterior cervical discectomy and fusion (ACDF) procedure using a Zero-P device and exhibited allergic symptoms 1 month after the surgery. RESULTS: The allergic symptoms included intermittent tingling and itches in the throat induced by speaking. Systemic rashes over the skin surface and congestion of the eyeball, and dysphagia were also present. Anti-allergic treatment did not resolve the symptoms. Patch tests revealed negative reactions to the rested reagents including titanium. Radiographic results showed solid bone fusion and no signs of chronic inflammation or hypotoxic infection in the surrounding tissues. Upon the patient's request, we removed the titanium screws and plate of the Zero-P device. No allergic reactions were observed after the surgery and at a 6-month follow-up. CONCLUSIONS: Even with a small implant such as the Zero-P device, allergy to titanium may still occur. This case demonstrated the need to screen for the presence of allergy to metals including titanium before the surgery.

Advisability of primary intraocular lens implantation for infants under 2: A systematic review and meta-analysis.

PURPOSES: The present meta-analysis compared the postoperative visual performance of primary intraocular lens (IOL) implantation and primary aphakia in cataract infants. METHODS: PubMed, Embase, Science Direct and Cochrane Library were searched, and postoperative visual acuity (VA) and complications were extracted and pooled. RESULTS: Three randomised controlled trails (RCTs) and five retrospective studies were included. The postoperative VA of children younger than 4.5 years in primary IOL group was better than that in primary aphakia group [MD = -0.14, 95% CI: (-0.23, -0.06), P = .90]. The subgroup analysis based on RCTs and on unilateral cataract surgery revealed the same result. There was no significant difference in the incidence of glaucoma, strabismus, retinal detachment and nystagmus between primary IOL group and primary aphakia group [OR = 1.02, 95% CI: (0.62, 1.68), P = .48 for glaucoma; OR = 0.76, 95% CI: (0.30, 1.90), P = .05 for strabismus; OR = 0.49, 95% CI: (0.07, 3.30), P = .34 for retinal detachment; OR = 1.26, 95% CI: (0.68, 2.36), P = .92 for nystagmus]. The proportion of patients requiring postoperative visual axis opacification (VAO) clearing was higher in primary IOL group than that in primary aphakia group [OR = 9.22, 95% CI: (4.74, 17.96), P = .16]. CONCLUSION: For infants under 2 years of age, primary IOL implantation would provide more visual benefits compared with primary aphakia did, though the benefits would taper off with the age reaching 4.5 years. Moreover, the current study revealed a higher VAO incidence r in primary IOL implantation group.

Robust Metal-Triazolate Frameworks for CO2 Capture from Flue Gas.

Construction of thermally and chemically robust metal-organic frameworks (MOFs) is highly desirable for postcombustion CO2 capture from flue gas containing water vapor and other acidic gases. Here we report a strategy based on appending amino groups to the triazolate linkers of MOFs to achieve exceptional chemical stability against aqueous, acidic, and basic conditions. These MOFs exhibit not only CO2/N2 thermodynamic adsorption selectivity as high as 120 but also CO2/H2O kinetic adsorption selectivity up to 70, featuring distinct adsorptive sites at the channel center for CO2 and at the corner for H2O, respectively. The best performing MOF in this series features low regeneration energy, high CO2 capture utility under humid conditions, and decent cycling performance for mimic flue gas.

Genuine Active Species Generated from Fe3 N Nanotube by Synergistic CoNi Doping for Boosted Oxygen Evolution Catalysis.

The surface reconstruction of oxygen evolution reaction (OER) catalysts has been proven favorable for enhancing its catalytic activity. However, what is the active site and how to promote the active species generation remain unclear and are still under debate. Here, the in situ synthesis of CoNi incorporated Fe3 N nanotubes (CoNi-Fe3 N) on the iron foil through the anodization/electrodeposition/nitridation process for use of boosted OER catalysis is reported. The synergistic CoNi doping induces the lattice expansion and up shifts the d-band center of Fe3 N, which enhances the adsorption of hydroxyl groups from electrolyte during the OER catalysis, facilitating the generation of active CoNi-FeOOH on the Fe3 N nanotube surface. As a result of this OER-conditioned surface reconstruction, the optimized catalyst requires an overpotential of only 285 mV at a current density of 10 mA cm-2 with a Tafel slope of 34 mV dec-1 , outperforming commercial RuO2 catalysts. Density functional theory (DFT) calculations further reveal that the Ni site in CoNi-FeOOH modulates the adsorption of OER intermediates and delivers a lower overpotential than those from Fe and Co sites, serving as the optimal active site for excellent OER performance.

Acoustic Realization of Quadrupole Topological Insulators.

A quadrupole topological insulator, being one higher-order topological insulator with nontrivial quadrupole quantization, has been intensely investigated very recently. However, the tight-binding model proposed for such emergent topological insulators demands both positive and negative hopping coefficients, which imposes an obstacle in practical realizations. Here, we introduce a feasible approach to design the sign of hopping in acoustics, and construct the first acoustic quadrupole topological insulator that stringently emulates the tight-binding model. The inherent hierarchy quadrupole topology has been experimentally confirmed by detecting the acoustic responses at the bulk, edge, and corner of the sample. Potential applications can be anticipated for the topologically robust in-gap states, such as acoustic sensing and energy trapping.

The effectiveness and safety of posterior scleral reinforcement with vitrectomy for myopic foveoschisis treatment: a systematic review and meta-analysis.

PURPOSE: To investigate the effectiveness and safety of posterior scleral reinforcement (PSR) combined with vitrectomy for myopic foveoschisis (MF) treatment. METHODS: We conducted a systematic review and meta-analysis. We evaluated the improvement of best-corrected visual acuity (BCVA) in logMAR unit, the percentage of patients with improved or stabled BCVA, benefit on axial length (AL), the retinal reattachment rate, the macular hole (MH) closure rate, as well as the complication rate. RESULTS: Fourteen studies (311 eyes) were included. Overall, patients' BCVA improved - 0.46 (95% confidence interval [CI] - 0.52, - 0.40) logMAR unit, with 80% (95%CI 74%, 85%) benefiting from BCVA improvement and 6% (95%CI 3%, 10%) suffering from BCVA loss. Patients' AL was shortened by - 1.74 (95%CI - 2.92, - 0.57) mm, and for patients whose AL was ≥ 30 mm, the average benefit reached - 3.68 (95%CI - 4.59, - 2.77) mm. Ninety-three percent (95%CI 89%, 96%) of the patients achieved retinal reattachment, and 65% (95%CI 47%, 80%) of the MH was closed. Patients' central foveal thickness decreased; the MD was - 187.32 (95%CI - 206.25, - 168.40) mm. The pooled complication rate was 9% (95%CI 8%, 19%), with extrusion, choroidal atrophy, and choroidal neovascularization being the most common complications. Subgroup analysis indicated no statistical difference in BCVA improvement, AL change, retinal reattachment rate, and complication rate between patients with or without MH. Subgroup analysis indicated no statistical difference in the above four outcomes between the primary and the recurrent patients either. There was no statistical difference in the above four outcomes no matter ILM peeling was combined or not. CONCLUSION: PSR combined with vitrectomy helps improve 80% MF patients' BCVA; the average benefit on BCVA is - 0.46 logMAR unit. The average change in AL is - 1.74 mm; patients with AL ≥ 30 mm benefit much more than the patients with AL < 30 mm. The retinal reattachment rate is up to 93%; the MH closure rate is 65%. About 9% patients will suffer from extrusion, choroidal atrophy, choroidal neovascularization, and other complications. The outcomes were not influenced by presence of MH, disease recurrence, or ILM peeling.

Prevalence and associated risk factors for childhood strabismus in Lhasa, Tibet, China: a cross-sectional, school-based study.

BACKGROUND: To estimate the prevalence of strabismus and associated risk factors among grade one school children in Lhasa, Tibet, China. METHODS: The Lhasa Childhood Eye Study (LCES) was a cross-sectional, school-based childhood study conducted in Grade one students from primary schools in Lhasa, Tibet, China. Comprehensive ophthalmic examinations and basic systemic examinations were evaluated. A questionnaire survey containing information about children, as well as parents' information, was sent to the corresponding parents of eligible children. The prevalence of strabismus and its 95% confidence interval was estimated. Univariate and multivariate logistic regression analyses were conducted to determine the associated risk factors. RESULTS: A total of 1942 eligible grade one students were enrolled, of which 1856 participants completed all examinations. The average age was 6.83 ± 0.46 years, 53% of participants were boys and 1762 were the Tibetan Minority. Over all, the prevalence of strabismus was 68/1856 (3.7%) (95%CI: 2.81,4.52), with no difference between the ages, genders, ethnicities and body mass index, while tilting one's head when writing may be a risk factor for strabismus (P = 0.004). Strabismus students had mean best corrected visual acuity of 0.16 ± 0.28(LogMAR), over 50% patients with esotropia were hyperopic, and participants who had stereopsis impairments showed a significant difference between esotropia and exotropia (P = 0.026). CONCLUSIONS: The prevalence of strabismus in LCES was 3.7%, which is higher than previous reports from Chinese childhood epidemiology studies. Strabismus is a common contributing factor to amblyopia. Tilting one's head when writing may be a risk factor. Esotropia is more likely to affect stereopsis and be associated with the refractive state of hyperopia. TRIAL REGISTRATION: The study has finished the clinical registration on Chinese Clinical Trial Registry. ( http://www.chictr.org.cn , ChiCTR1900026693 ).

Identification of transcobalamin deficiency with two novel mutations in the TCN2 gene in a Chinese girl with abnormal immunity: a case report.

BACKGROUND: Transcobalamin (TC) transports vitamin B12 from blood into cells. TC II deficiency is a rare autosomal recessive disorder. It is characterized by failure to thrive, diarrhoea, pallor, anaemia, pancytopenia or agammaglobulinemia. It is usually confirmed by molecular analysis of the TCN2 gene. We report a 2-month-old girl with two novel mutations, which were first reported in humans. CASE PRESENTATION: We present a 2-month-old Chinese girl with pancytopenia, severe combined immunodeficiency disease, and megaloblastic anaemia. Targeted next-generation sequencing (NGS) was performed, which detected compound heterozygous variants in exon 7 of the TCN2 gene (Mutation 1: c.1033 C > T; Mutation 2: c.1017-1031delinsGTAACAGAGATGGTT). These mutations result in stop codons in TCN2. The c.1033C > T mutation causes a stop at codon 345 (p.Gln345Ter), and the c.1017-1031delinsGTAACAGAGATGGTT mutation causes a stop at codon 340 (p.Leu340Ter). After being diagnosed, she was treated with intramuscular 1 mg hydroxycobalamin (OH-Cbl) every day for 2 months. The CBC value returned to normal after half a month. The peripheral blood lymphocyte subsets and immunoglobulin recovered after 2 months. Then, the dosage of OH-Cbl was gradually reduced. CONCLUSIONS: TC II deficiency is a serious complication that requires lifelong treatment. Its diagnosis is difficult due to the lack of clearly identifiable symptoms. Genetic testing should be performed as early as possible if this disease is suspected. The specific observations of this case report make a considerable contribution to the literature and provide a reference for the diagnosis and treatment of future cases.

Optoacoustic mesoscopy shows potential to increase accuracy of allergy patch testing.

BACKGROUND: Differentiation between irritant and allergic skin reactions in epicutaneous patch testing is based largely on subjective clinical criteria, with the risk of high intraobserver and interobserver variability. Novel dermatological imaging using optoacoustic mesoscopy allows quantitative three-dimensional assessment of microvascular biomarkers. OBJECTIVES: We investigated the potential of optoacoustic imaging to improve the precision of patch test evaluation. METHODS: Sixty-nine test reactions and 48 healthy skin sections in 52 patients with suspected type IV allergy were examined using raster-scan optoacoustic mesoscopy. RESULTS: We identified biomarkers from the optoacoustic images. Allergic reactions were associated with higher fragmentation of skin vasculature than irritant reactions (19.5 ± 9.7 vs 14.3 ± 3.7 fragments/100 pixels2 ; P < .05), as well as lower ratio of low- to high-frequency acoustic signals (1.6 ± 0.5 vs 2.0 ± 0.6, P < .05). Allergic reactions graded "++" showed higher vessel fragmentation than reactions graded "+" (25.4 ± 13.2 vs 17.1 ± 6.5 fragments/100 pixels2 ; P < .05). A linear model combining the biomarkers fragmentation and frequency ratio could differentiate allergic from irritant test reactions with an area under the receiving operator characteristic curve of 0.80 (95% confidence interval 0.64-0.91), reaching a sensitivity of 81% and specificity of 63%. CONCLUSIONS: Optoacoustic mesoscopy shows potential to help in differentiating between allergic and irritant test reactions based on novel biomarkers that may reflect vasodilation, vessel tortuosity, and edema.

Lead immobilization processes in soils subjected to freeze-thaw cycles.

Soil freeze-thaw cycles (FTCs) change the physical and chemical properties of soils; however, information is limited about the consequences for heavy metal sorption and desorption. Lead (Pb) sorption isotherms and successive desorption tests were measured for three soils from North China (Chestnut, Lou and Black), following multiple freeze-thaw cycles (0, 1, 3, 6 and 9 FTCs) of -5 °C for 12 h and then +5 °C for 12 h. Lead adsorption dominated the sorption processes for all soils, and sorption capacity increased with additional FTCs. The Freundlich affinity parameter of soils for Pb sorption (i.e. A; Lß mmol1-ß kg-1), was linearly correlated with carbonate content for soils with multiple FTCs. The effects of FTCs on lead adsorption may be more dependent on carbonate and clay contents than organic matter (OM), cation exchange capacity (CEC) and amorphous iron content. Repeated FTCs increased the pH of soil solutions at applied Pb concentrations >1.4 mmol L-1, which could facilitate formation of inner-sphere complexes of Pb in studied soils. Cation exchange, a weak association, could occupy specific adsorption sites with increasing Pb doses in soils and it can also be facilitated by FTCs. Our results demonstrate the great potential for increasing Pb immobilization with repeated FTCs, by facilitating the formation of both inner-sphere and outer-sphere complexes. Hence, these findings provide useful information on Pb immobilization in contaminated soils that undergo frequent FTCs and offer an additional insight into predicting Pb behavior in cold and freezing environments like the polar regions.

Probing Weyl Physics with One-Dimensional Sonic Crystals.

Recently, intense efforts have been devoted to realizing classical analogues of various topological phases of matter. In this Letter, we explore the intriguing Weyl physics by a simple one-dimensional sonic crystal, in which two extra structural parameters are combined to construct a synthetic three-dimensional space. Based on our ultrasonic experiments, we have not only observed the synthetic Weyl points, but also probed the novel reflection phase singularity that connects inherently with the topological robustness of Weyl points. The presence of topologically nontrivial interface modes has been demonstrated further. As the first realization of topological acoustics in synthetic space, our study exhibits great potential of probing high-dimensional topological phenomena by such easily fabricated and detected low-dimension acoustic systems.