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1.
Nano Lett ; 24(22): 6665-6672, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38767991

RESUMEN

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.

2.
Small ; : e2401078, 2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38593301

RESUMEN

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.

3.
Phys Rev Lett ; 132(6): 066601, 2024 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-38394560

RESUMEN

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.

4.
Phys Rev Lett ; 132(26): 266602, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38996328

RESUMEN

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.

5.
Nature ; 560(7716): 61-64, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-30068954

RESUMEN

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.

6.
Small ; 19(17): e2206439, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36703537

RESUMEN

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.

7.
J Exp Bot ; 74(3): 723-742, 2023 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-36271923

RESUMEN

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.


Asunto(s)
Calor , Árboles , Transporte Biológico , Transpiración de Plantas , Agua , Bibliometría
8.
Phys Rev Lett ; 130(11): 116103, 2023 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-37001063

RESUMEN

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.

9.
Br J Neurosurg ; 37(4): 916-920, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32003246

RESUMEN

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.


Asunto(s)
Hipersensibilidad , Fusión Vertebral , Masculino , Humanos , Persona de Mediana Edad , Resultado del Tratamiento , Titanio/efectos adversos , Prótesis e Implantes , Hipersensibilidad/etiología , Hipersensibilidad/cirugía , Discectomía/efectos adversos , Discectomía/métodos , Fusión Vertebral/métodos , Vértebras Cervicales/diagnóstico por imagen , Vértebras Cervicales/cirugía
10.
Int J Clin Pract ; 75(9): e14143, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33724630

RESUMEN

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.


Asunto(s)
Extracción de Catarata , Catarata , Niño , Preescolar , Estudios de Seguimiento , Humanos , Lactante , Implantación de Lentes Intraoculares , Complicaciones Posoperatorias/epidemiología , Estudios Retrospectivos , Agudeza Visual
11.
J Am Chem Soc ; 142(6): 2750-2754, 2020 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-31968944

RESUMEN

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.

12.
Small ; 16(40): e2003824, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32830455

RESUMEN

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.

13.
Phys Rev Lett ; 124(20): 206601, 2020 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-32501055

RESUMEN

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.

14.
Graefes Arch Clin Exp Ophthalmol ; 258(2): 257-271, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31823060

RESUMEN

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.


Asunto(s)
Fóvea Central/patología , Miopía Degenerativa/complicaciones , Retinosquisis/cirugía , Esclerótica/cirugía , Vitrectomía/métodos , Fóvea Central/cirugía , Humanos , Retinosquisis/diagnóstico , Retinosquisis/etiología , Tomografía de Coherencia Óptica , Resultado del Tratamiento , Agudeza Visual
15.
BMC Ophthalmol ; 20(1): 463, 2020 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-33238929

RESUMEN

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 ).


Asunto(s)
Ambliopía , Estrabismo , Niño , China/epidemiología , Estudios Transversales , Femenino , Humanos , Masculino , Prevalencia , Factores de Riesgo , Instituciones Académicas , Estrabismo/epidemiología , Estrabismo/etiología , Tibet
16.
BMC Pediatr ; 20(1): 460, 2020 10 06.
Artículo en Inglés | MEDLINE | ID: mdl-33023511

RESUMEN

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.


Asunto(s)
Anemia Megaloblástica , Deficiencia de Vitamina B 12 , China , Femenino , Humanos , Lactante , Mutación , Transcobalaminas/genética , Vitamina B 12
17.
Contact Dermatitis ; 83(3): 206-214, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32311105

RESUMEN

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.


Asunto(s)
Dermatitis Alérgica por Contacto/diagnóstico por imagen , Pruebas del Parche/instrumentación , Técnicas Fotoacústicas/métodos , Piel/diagnóstico por imagen , Adulto , Estudios de Casos y Controles , Dermatología/métodos , Femenino , Humanos , Persona de Mediana Edad
18.
Ecotoxicol Environ Saf ; 192: 110288, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32078838

RESUMEN

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.


Asunto(s)
Congelación , Plomo/análisis , Contaminantes del Suelo/análisis , Suelo/química , Adsorción , Cationes , China
19.
Phys Rev Lett ; 122(13): 136802, 2019 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-31012611

RESUMEN

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.

20.
Acta Haematol ; 142(3): 162-170, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31091521

RESUMEN

Aplastic anemia (AA) is a hematologic disease characterized by pancytopenia and hypocellular bone marrow, potentially leading to chronic anemia, hemorrhage, and infection. The China Aplastic Anemia Committee and British Committee for Standards in Haematology guidelines recommend hematopoietic stem-cell transplantation (HSCT) or immunosuppressive therapy (IST) comprising antithymocyte globulin (ATG) with cyclosporine (CsA) as initial treatment for AA patients. With limited epidemiological data on the clinical management of AA in Asia, a prospective cohort registry study involving 22 AA treatment centers in China was conducted to describe the disease characteristics of newly diagnosed AA patients and investigate real-world treatment patterns and patient outcomes. Of 340 AA patients, 72.9, 12.6, and 3.5% were receiving IST, traditional Chinese medicine, and HSCT, respectively, at baseline; only 22.2% of IST-treated patients received guideline-recommended ATG with CsA initially. Almost all patients received supportive care (95.6%) as blood transfusion (97.8%), antibiotics (63.7%), and/or hematopoietic growth factors (58.2%). Overall, 64.8% achieved a partial or complete response, and 0.9% experienced relapse. No new safety concerns were identified; serious adverse events were largely unrelated to the treatment regimen. These results demonstrate the need to identify and minimize treatment barriers to standardize and align AA management in China with treatment guideline recommendations and further improve patient outcomes.


Asunto(s)
Anemia Aplásica , Suero Antilinfocítico/administración & dosificación , Ciclosporina/administración & dosificación , Trasplante de Células Madre Hematopoyéticas , Terapia de Inmunosupresión , Medicina Tradicional China , Sistema de Registros , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Aloinjertos , Anemia Aplásica/mortalidad , Anemia Aplásica/terapia , Niño , Preescolar , China/epidemiología , Supervivencia sin Enfermedad , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Tasa de Supervivencia
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