Plasticity in single-crystalline Mg3Bi2 thermoelectric material.

Most of the state-of-the-art thermoelectric materials are inorganic semiconductors. Owing to the directional covalent bonding, they usually show limited plasticity at room temperature1,2, for example, with a tensile strain of less than five per cent. Here we discover that single-crystalline Mg3Bi2 shows a room-temperature tensile strain of up to 100 per cent when the tension is applied along the (0001) plane (that is, the ab plane). Such a value is at least one order of magnitude higher than that of traditional thermoelectric materials and outperforms many metals that crystallize in a similar structure. Experimentally, slip bands and dislocations are identified in the deformed Mg3Bi2, indicating the gliding of dislocations as the microscopic mechanism of plastic deformation. Analysis of chemical bonding reveals multiple planes with low slipping barrier energy, suggesting the existence of several slip systems in Mg3Bi2. In addition, continuous dynamic bonding during the slipping process prevents the cleavage of the atomic plane, thus sustaining a large plastic deformation. Importantly, the tellurium-doped single-crystalline Mg3Bi2 shows a power factor of about 55 microwatts per centimetre per kelvin squared and a figure of merit of about 0.65 at room temperature along the ab plane, which outperforms the existing ductile thermoelectric materials3,4.

Self-Floating Nanoporous High-Entropy Oxides with Tunable Bandgap for Efficient Solar Seawater Desalination.

Nanoporous high-entropy oxide (np-HEO) powders with tunable composition are integrated with a poly(vinylidene fluoride) network to create self-floating solar absorber films for seawater desalination. By progressively increasing the element count, we obtain an optimized 9-component AlNiCoFeCrMoVCuTi-Ox. Density functional theory (DFT) calculations reveal a remarkable reduction in its bandgap, facilitating the light-induced migration of electrons to conduction bands to generate electron-hole pairs, which recombine to produce heat. Simultaneously, the intricate light reflection and refraction pathways, shaped by the nanoporous structure, coupled with the reduced thermal conductivity attributed to the suboptimal crystalline quality of the np-HEO ensure an effective conversion of captured light into thermal energy. Consequently, all these films demonstrate an impressive absorbance rate exceeding 93% across the 250-2500 nm spectral range. Under one sun, the surface temperature of the 9-component film rapidly rises to 110 °C within 90 s with a high pure water evaporation rate of 2.16 kg m-2 h-1.

circGRAMD1B contributes to migration, invasion and epithelial-mesenchymal transition of lung adenocarcinoma cells via modulating the expression of SOX4.

Lung adenocarcinoma (LUAD) represents the subtype of non-small-cell lung cancer (NSCLC), with the high morbidity over the world. Mounting studies have highlighted the important roles of circular RNAs (circRNA) in cancers, including LUAD. This study mainly focused on revealing the role of circGRAMD1B and its relevant regulatory mechanism in LUAD cells. RT-qPCR and Western blot were conducted to detect the expression of target genes. Function assays were performed to determine the effect of related genes on migration, invasion, and epithelial-mesenchymal transition (EMT) of LUAD cells. Mechanism analyses were conducted to figure out the specific mechanism with regard to circGRAMD1B and its downstream molecules as well. Based on the experimental results, circGRAMD1B was upregulated in LUAD cells and promoted the migration, invasion, and EMT of LUAD cells. Mechanically, circGRAMD1B sponged miR-4428 to upregulate the expression of SOX4. In addition, SOX4 activated the expression of MEX3A at the transcriptional level, thereby modulating PI3K/AKT pathway to facilitate LUAD cell malignant behaviors. In conclusion, circGRAMD1B is discovered to modulate miR-4428/SOX4/MEX3A axis to further activate PI3K/AKT pathway, finally boosting migration, invasion, and EMT of LUAD cells.

Enhanced Photothermal Steam Generation and Gold Using the Efficiency of Ultralight Gold Foam with Hierarchical Porosity.

Controlling the optical properties of metal plasma nanomaterials through structure manipulation has attracted great attention for solar steam generation. However, realizing broadband solar absorption for high-efficiency vapor generation is still challenging. In this work, a free-standing ultralight gold film/foam with a hierarchical porous microstructure and high porosity is obtained through controllably etching a designed cold-rolled (NiCoFeCr)99Au1 high-entropy precursor alloy with a unique grain texture. During chemical dealloying, the high-entropy precursor went through anisotropic contraction, resulting in a larger surface area compared with that from the Cu99Au1 precursor although the volume shrinkage is similar (over 85%), which is beneficial for the photothermal conversion. The low Au content also results in a special hierarchical lamellar microstructure with both micropores and nanopores within each lamella, which significantly broadens the optical absorption range and makes the optical absorption of the porous film reach 71.1-94.6% between 250 and 2500 nm. In addition, the free-standing nanoporous gold film has excellent hydrophilicity, with the contact angle reaching zero within 2.2 s. Thus, the 28 h dealloyed nanoporous gold film (NPG-28) exhibits a rapid evaporation rate of seawater under 1 kW m-2 light intensity, reaching 1.53 kg m-2 h-1, and the photothermal conversion efficiency reaches 96.28%. This work demonstrates the enhanced noble metal gold using efficiency and solar thermal conversion efficiency by controlled anisotropic shrinkage and forming a hierarchical porous foam.

Eight-Component Nanoporous High-Entropy Oxides with Low Ru Contents as High-Performance Bifunctional Catalysts in Zn-Air Batteries.

One major challenge in heterogeneous catalysis is to reduce the usage of noble metals while maintaining the overall catalytic stability and efficiency in various chemical environments. In this work, a series of high-entropy catalysts are synthesized by a chemical dealloying method and find the increased entropy effect and non-noble metal contents would facilitate the formation of complete oxides with low crystallinity. Importantly, an optimal eight-component high-entropy oxide (HEO, Al-Ni-Co-Ru-Mo-Cr-Fe-Ti) is identified, which exhibits further enhanced catalytic activity for the oxygen evolution reaction (OER) as compared to the previously reported quinary AlNiCoRuMo and the widely-used commercial RuO2 catalysts, and at the same time similar catalytic activity for the oxygen reduction reaction (ORR) as the commercial Pt/C with a half-wave potential of 0.87 V. Such high-performance bi-functional catalysts, however, only require a half loading amount of Ru as compared to the quinary AlNiCoRuMo, due to the underlying Cr-Fe synergistic effects on tuning the electronic structures at active surface sites, as revealed by the first-principles density functional theory calculations of the authors. The eight-component HEO also demonstrates excellent stability under continuous electrochemical working conditions, suitable for a wide range of applications such as metal-air batteries.

Highly Strengthened and Toughened Zn-Li-Mn Alloys as Long-Cycling Life and Dendrite-Free Zn Anode for Aqueous Zinc-Ion Batteries.

Zn-ion batteries (ZIBs) using aqueous electrolyte, recently, have been a hot topic owing to the high safety, low cost, and high specific energy capacity. However, the formation of dendrite and side reactions on the Zn anode during cycling inhibit the application of ZIBs. An advanced Zn anode by alloying a small amount of Li and Mn with Zn is hereby reported. It is found that Li and Mn can form cationic ions which restrain lateral diffusion of Zn ions and regulate zinc electrodeposition through the electrostatic shield mechanism. As a result, the formation of Zn dendrite is greatly inhibited. This process also mitigates the formation of Zn-based byproduct and Zn passivation. Consequently, the symmetric ZnLiMn/ZnLiMn cell presents a small overpotential of 30 mV at 1 mA cm-2 , greatly enhanced cycling durability (1000 h at a current density of 1 mA cm-2 ), and a dendrite-free morphology after cycles. Moreover, the authors find that the ZnLiMn alloy has greatly enhanced mechanical properties. The assembled ZnLiMn/MnO2 full cell can retain 96% capacity after 400 cycles at 1 C. Thus, the alloying low-cost Li/Mn strategy is very promising for large-scale production of dendrite-free Zn electrode in rechargeable ZIBs.

Passive Radiative Cooling Enables Improved Performance in Wearable Thermoelectric Generators.

Wearable thermoelectric generators have great potential to be utilized as the power supply for wearable electronics. However, the limited temperature difference across the thermoelectric generators significantly degrades the output performance, which is anticipated to be improved by enhancing the thermal radiation at the cold side without extra energy consumption. In this paper, the impact of thermal radiation on the performance of thermoelectric generators in different environments is simulated and the enhanced performance in a wearable thermoelectric generator combined with a radiative cooling coating is experimentally verified. Compared with the pristine device, the wearable thermoelectric generator with radiative cooling coating can not only achieve an ≈128% improvement of output power in exposed environments, but also exhibit an ≈96% improvement of output power in non-exposed environments. The indoor output performance of the wearable thermoelectric generator with a radiative cooling coating due to its stable voltage output is extensively investigated, which shows an output power density of ≈5.5 µW cm-2 at the indoor temperature of 295 K, doubled that without a radiative cooling coating. This work paves a new way for further enhancing the performance of thermoelectric generators via passive radiative cooling.

Zintl-phase Eu2ZnSb2: A promising thermoelectric material with ultralow thermal conductivity.

Zintl compounds are considered to be potential thermoelectric materials due to their "phonon glass electron crystal" (PGEC) structure. A promising Zintl-phase thermoelectric material, 2-1-2-type Eu2ZnSb2 (P63/mmc), was prepared and investigated. The extremely low lattice thermal conductivity is attributed to the external Eu atomic layers inserted in the [Zn2Sb2]2- network in the structure of 1-2-2-type EuZn2Sb2 [Formula: see text], as well as the abundant inversion domain boundary. By regulating the Zn deficiency, the electrical properties are significantly enhanced, and the maximum ZT value reaches ∼1.0 at 823 K for Eu2Zn0.98Sb2 Our discovery provides a class of Zintl thermoelectric materials applicable in the medium-temperature range.

MOF Structure Engineering to Synthesize CoNC Catalyst with Richer Accessible Active Sites for Enhanced Oxygen Reduction.

Single-atom cobalt-based CoNC are promising low-cost electrocatalysts for oxygen reduction reaction (ORR). However, further increasing the single cobalt-based active sites and the ORR activity remain a major challenge. Herein, an acetate (OAc) assisted metal-organic framework (MOF) structure-engineering strategy is developed to synthesize hierarchical accordion-like MOF with higher loading amount and better spatial isolation of Co and much higher yield when compared with widely reported polyhedron MOF. After pyrolysis, the accordion-structured CoNC (CoNC (A)) is loaded with denser CoN4 active sites (Co: 2.88 wt%), approximately twice that of Co in the CoNC reported. The presence of OAc in MOF also induces the generation of big pores (5-50 nm) for improving the accessibility of active sites and mass transfer during catalytic reactions. Consequently, the CoNC (A) catalyst shows an admirable ORR activity with a E1/2 of 0.89 V (40 mV better than Pt/C) in alkaline electrolytes, outstanding durability, and absolute tolerance to methanol in both alkaline and acidic media. The CoNC-based Zn-air battery exhibits a high specific capacity (976 mAh g-1 Zn ), power density (158 mW cm-2 ), rate capability, and long-term stability. This work demonstrates a reliable approach to construct single atom doped carbon catalysts with denser accessible active sites through MOF structure engineering.

Nanoporous Al-Ni-Co-Ir-Mo High-Entropy Alloy for Record-High Water Splitting Activity in Acidic Environments.

Ir-based binary and ternary alloys are effective catalysts for the electrochemical oxygen evolution reaction (OER) in acidic solutions. Nevertheless, decreasing the Ir content to less than 50 at% while maintaining or even enhancing the overall electrocatalytic activity and durability remains a grand challenge. Herein, by dealloying predesigned Al-based precursor alloys, it is possible to controllably incorporate Ir with another four metal elements into one single nanostructured phase with merely ≈20 at% Ir. The obtained nanoporous quinary alloys, i.e., nanoporous high-entropy alloys (np-HEAs) provide infinite possibilities for tuning alloy's electronic properties and maximizing catalytic activities owing to the endless element combinations. Particularly, a record-high OER activity is found for a quinary AlNiCoIrMo np-HEA. Forming HEAs also greatly enhances the structural and catalytic durability regardless of the alloy compositions. With the advantages of low Ir loading and high activity, these np-HEA catalysts are very promising and suitable for activity tailoring/maximization.

Zebrafish B Cell Development without a Pre-B Cell Stage, Revealed by CD79 Fluorescence Reporter Transgenes.

CD79a and CD79b proteins associate with Ig receptors as integral signaling components of the B cell Ag receptor complex. To study B cell development in zebrafish, we isolated orthologs of these genes and performed in situ hybridization, finding that their expression colocalized with IgH-µ in the kidney, which is the site of B cell development. CD79 transgenic lines were made by linking the promoter and upstream regulatory segments of CD79a and CD79b to enhanced GFP to identify B cells, as demonstrated by PCR analysis of IgH-µ expression in sorted cells. We crossed these CD79-GFP lines to a recombination activating gene (Rag)2:mCherry transgenic line to identify B cell development stages in kidney marrow. Initiation of CD79:GFP expression in Rag2:mCherry+ cells and the timing of Ig H and L chain expression revealed simultaneous expression of both IgH-µ- and IgL-κ-chains, without progressing through the stage of IgH-µ-chain alone. Rag2:mCherry+ cells without CD79:GFP showed the highest Rag1 and Rag2 mRNAs compared with CD79a and CD79b:GFP+ B cells, which showed strongly reduced Rag mRNAs. Thus, B cell development in zebrafish does not go through a Raghi CD79+IgH-µ+ pre-B cell stage, different from mammals. After the generation of CD79:GFP+ B cells, decreased CD79 expression occurred upon differentiation to Ig secretion, as detected by alteration from membrane to secreted IgH-µ exon usage, similar to in mammals. This confirmed a conserved role for CD79 in B cell development and differentiation, without the requirement of a pre-B cell stage in zebrafish.

N-type Bi-doped SnSe Thermoelectric Nanomaterials Synthesized by a Facile Solution Method.

An n-type Bi-doped SnSe was synthesized by a facile solution method followed by spark plasma sintering. We used bismuth(III) 2-ethyhexanoate as a cationic dopant precursor, which can absorb on the powder surface and then diffuse into the lattice to realize the substitution of Sn by Bi. A strip structure with low-angle boundary was constructed for effective phonon scattering. With increasing content of Bi, the carrier concentration decreased from 1.35 × 1019 cm-3 (p-type) in undoped SnSe to 4.7 × 1014 cm-3 (n-type) in Sn0.99Bi0.01Se and then increased to 1.3 × 1015 cm-3 (n-type) in Sn0.97Bi0.03Se. The Seebeck coefficient changed from positive to negative and presented n-type conducting behavior in the whole measured temperature range from 300 to 773 K, reaching a maximum absolute value of ∼900 µV K-1 at room temperature and ∼300 µV K-1 at 773 K. Considering the rich variety of metal 2-ethylhexanoates, higher thermoelectric performance is expected by different cationic doping in solution-synthesized nanomaterials.

T-type calcium channels, but not Cav3.2, in the peripheral sensory afferents are involved in acute itch in mice.

T-type calcium channels are prominently expressed in primary nociceptive fibers and well characterized in pain processes. Although itch and pain share many similarities including primary sensory fibers, the function of T-type calcium channels on acute itch has not been explored. We investigated whether T-type calcium channels expressed within primary sensory fibers of mouse skin, especially Cav3.2 subtype, involve in chloroquine-, endothelin-1- and histamine-evoked acute itch using pharmacological, neuronal imaging and behavioral analyses. We found that pre-locally blocking three subtypes of T-type calcium channels in the peripheral afferents of skins, yielded an inhibition in acute itch or pain behaviors, while selectively blocking the Cav3.2 channel in the skin peripheral afferents only inhibited acute pain but not acute itch. These results suggest that T-type Cav3.1 or Cav3.3, but not Cav3.2 channel, have an important role in acute itch processing, and their distinctive roles in modulating acute itch are worthy of further investigation.

The pressure-temperature phase diagram of pure Co based on first-principles calculations.

We optimized the high pressure-temperature phase diagram of pure Co up to the liquidus temperature and 120 GPa, based on thermodynamic properties calculated using first-principles. The Gibbs energy for each phase was evaluated in the framework of a quasiharmonic approximation, with a consideration of the thermal electronic contribution at finite temperatures. Particularly, the liquidus temperature, as a function of pressure, was determined using classical Molecular Dynamics simulations. Our results in this work successfully integrated experimental observations and the previous theoretical predictions. The critical solid phase transitions of ε → γf and ε → ß were clarified using the Gibbs energy as a function of pressure and temperature. In addition, the magnetism of ß above 70 GPa was verified to be nonmagnetic. The difference between γp and ß, which was unclear before, has been illustrated to be associated with the magnetic transformation from the paramagnetic state of the γp phase to the nonmagnetic state of the ß phase rather than the structural transformation.

Atomic-Level Mechanisms of Nucleation of Pure Liquid Metals during Rapid Cooling.

To obtain a material with the desired performance, the atomic-level mechanisms of nucleation from the liquid to solid phase must be understood. Although this transition has been investigated experimentally and theoretically, its atomic-level mechanisms remain debatable. In this work, the nucleation mechanisms of pure Fe under rapid cooling conditions are investigated. The local atomic packing stability and liquid-to-solid transition-energy pathways of Fe are studied using molecular dynamics simulations and first-principle calculations. The results are expressed as functions of cluster size in units of amorphous clusters (ACs) and body-centered cubic crystalline clusters (BCC-CCs). We found the prototypes of ACs in supercooled liquids and successfully divided these ACs to three categories according to their transition-energy pathways. The information obtained in this study could contribute to our current understanding of the crystallization of metallic melts during rapid cooling.

Erythrocytosis associated with hyperthyroidism: a rare case report and clinical study of possible mechanism.

PURPOSE: To report a rare case of erythrocytosis that occurred in close association with Graves' hyperthyroidism. In order to explore the role of altered erythropoiesis in hyperthyroidism, factors related to erythropoiesis were studied in 30 patients with Graves' hyperthyroidism. METHOD: The relationship between thyroid hormone level and erythrocytosis was studied in a patient with Graves' hyperthyroidism and erythrocytosis. Later, 30 consecutive patients with proven untreated Graves' hyperthyroidism and 30 age- and sex-matched healthy controls were recruited. All patients received methimazole therapy. Erythrocyte indices, thyroid function, serum erythropoietin (EPO), and hypoxia-inducible factor-1α (HIF-1α) concentrations were measured before and after eight weeks of therapy. RESULTS: In our case study, erythrocytosis relapsed with elevation of thyroid hormones. Methimazole or subsequent radioiodine therapy reduced the conditions of erythrocytosis and thyroid function returned to normal. In the clinical study, erythrocyte counts, serum erythropoietin, and HIF-1α levels in the hyperthyroid group were significantly higher than those in the control subjects. All subjects were grouped together for correlation analyses and HIF-1α was shown to correlate with total triiodothyronine (TT(3)), total thyroxine (TT(4)), and EPO levels. The correlation between EPO and TT(3) or TT(4) approached significance. After eight weeks of anti-thyroid drug therapy, a small but statistically significant increase in hemoglobin and erythrocyte count with a significant decrease in HIF-1α and EPO level was seen in hyperthyroid subjects. CONCLUSION: Erythrocytosis may appear in patients with hyperthyroidism, and one possible mechanism is thyroid hormone-induced augmentation of HIF-1α, resulting in increased EPO levels.

Neuroprotectin/protectin D1 protects against neuropathic pain in mice after nerve trauma.

Prevalence of neuropathic pain is high after major surgery. However, effective treatment for preventing neuropathic pain is lacking. Here we report that perisurgical treatment of neuroprotectin D1/protectin D1 (NPD1/PD1), derived from docosahexaenoic acid, prevents nerve injury-induced mechanical allodynia and ongoing pain in mice. Intrathecal post-treatment of NPD1/PD1 also effectively reduces established neuropathic pain and produces no apparent signs of analgesic tolerance. Mechanistically, NPD1/PD1 treatment blocks nerve injury-induced long-term potentiation, glial reaction, and inflammatory responses, and reverses synaptic plasticity in the spinal cord. Thus, NPD1/PD1 and related mimetics might serve as a new class of analgesics for preventing and treating neuropathic pain.

Bubbling resilient 3D free-standing nanoporous graphene with an encapsulated multicomponent nano-alloy for enhanced electrocatalysis.

The design and synthesis of highly durable and active electrocatalysts are crucial for improving the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). In this work, we present a novel dealloyed nanoporous PtCuNiCoMn multicomponent alloy with ligaments/pores ranging from 2-3 nm, which is in situ encapsulated in a three-dimensional, free-standing nanoporous nanotubular graphene network featuring a pore/tube diameter of ∼200 to 300 nm. This method allows precise control over the noble metal loading and alloy composition while preventing noble metal loss throughout the preparation process. The innovative bimodal nanoporous graphene/alloy structure, coupled with an open 3D spongy morphology, and optimized surface Pt electronic structure through multicomponent interaction, significantly enhances the activity for the HER/ORR, outperforming commercial Pt/C. Moreover, this design addresses the issues of Pt nanoparticle aggregation and detachment from carbon supports that typically exist in Pt/C-type catalysts, thereby substantially improving the catalytic durability, even under intense gas bubbling conditions.

Mecp2 Deficiency in Peripheral Sensory Neuron Improves Cognitive Function by Enhancing Hippocampal Dendritic Spine Densities in Mice.

Methyl-CpG-binding protein 2 (Mecp2) is an epigenetic modulator and numerous studies have explored its impact on the central nervous system manifestations. However, little attention has been given to its potential contributions to the peripheral nervous system (PNS). To investigate the regulation of Mecp2 in the PNS on specific central regions, we generated Mecp2fl/flAdvillincre mice with the sensory-neuron-specific deletion of the Mecp2 gene and found the mutant mice had a heightened sensitivity to temperature, which, however, did not affect the sense of motion, social behaviors, and anxiety-like behavior. Notably, in comparison to Mecp2fl/fl mice, Mecp2fl/flAdvillincre mice exhibited improved learning and memory abilities. The levels of hippocampal synaptophysin and PSD95 proteins were higher in Mecp2fl/flAdvillincre mice than in Mecp2fl/fl mice. Golgi staining revealed a significant increase in total spine density, and dendritic arborization in the hippocampal pyramidal neurons of Mecp2fl/flAdvillincre mice compared to Mecp2fl/fl mice. In addition, the activation of the BDNF-TrkB-CREB1 pathway was observed in the hippocampus and spinal cord of Mecp2fl/flAdvillincre mice. Intriguingly, the hippocampal BDNF/CREB1 signaling pathway in mutant mice was initiated within 5 days after birth. Our findings suggest a potential therapeutic strategy targeting the BDNF-TrkB-CREB1 signaling pathway and peripheral somasensory neurons to treat learning and cognitive deficits associated with Mecp2 disorders.

CALPHAD accelerated design of advanced full-Zintl thermoelectric device.

Since thermoelectric materials have different physical and chemical properties, the design of contact layers requires dedicated efforts, and the welding temperatures are distinctly different. Therefore, a general interface design and connection technology can greatly facilitate the development of thermoelectric devices. Herein, we proposed a screening strategy for the contact materials based on the calculation of phase diagram method, and Mg2Ni has been identified as a matched contact layer for n-type Mg3Sb2-based materials. And this screening strategy can be effectively applied to other thermoelectric materials. By adopting the low-temperature sintering silver nanoparticles technology, the Zintl phase thermoelectric device can be fabricated at low temperature but operate at medium temperature. The single-leg n-type Mg3.15Co0.05SbBi0.99Se0.01 device achieves an efficiency of ~13.3%, and a high efficiency of ~11% at the temperature difference of 430 K has been realized for the Zintl phase thermoelectric device comprised together with p-type Yb0.9Mg0.9Zn1.198Ag0.002Sb2. Additionally, the thermal aging and thermal cycle experiments proved the long-term reliability of the Mg2Ni/Mg3.15Co0.05SbBi0.99Se0.01 interface and the nano-silver sintering joints. Our work paves an effective avenue for the development of advanced devices for thermoelectric power generation.