Seeded Growth of Size-Tunable Au@Ag Core-Shell Nano-Octahedra and Their Yolk-Shell Derivatives for Near Infrared Photothermal Conversion.

Gold-based nanostructures with well-defined morphologies and hollow interiors have significant potential as a versatile platform for various plasmonic applications including biomedical diagnostics and sensing. In this study, we report the synthesis of Au@Ag core-shell nanocrystals with perfect octahedral shapes and tunable edge lengths via seeded growth. These nanocrystals were then oxidatively carved into yolk-shell nanocages with a retained octahedral morphology. The increase in octahedral edge length and volume of the interior hollow cavity synergistically leads to a red-shift of the LSPR peak. As a result, the optimized Au@AuAg yolk-shell octahedral nanocages showed a remarkable temperature increase of 23 °C upon 15 min irradiation of an 808 nm laser at a power density of 1 W cm-2. This study provides a feasible strategy for creating octahedral AuAg nanostructures with tunable sizes and hollow interiors and validates their promising use in NIR photothermal conversion.

Selenium-Doped Seeded Growth of Truncated Octahedral Gold Nanocrystals with Surface Concavities for Surface-Enhanced Raman Spectroscopy.

Concave nanocrystals stand out as a testament to the importance of the nanoscale morphology in dictating the functional properties of materials. In this report, we introduce a facile synthesis method for producing gold (Au) nanocrystals with a truncated octahedral morphology that features surface concavities (Au CNTOs). The incorporation of selenium (Se) doping into the truncated octahedral Au seeds was essential for their enlargement and the formation of concave structures. By simply adjusting the quantity of seeds, we could control the size of the nanocrystals while maintaining their distinctive morphology and surface concavity. The formation mechanism suggests that Se doping likely passivates the side faces, thereby slowing growth and promoting atomic deposition at the edges and corners. The resulting Se-doped Au CNTOs exhibited strong localized surface plasmon resonance (LSPR) absorptions in the visible spectrum and the SERS performance of their assemblies was demonstrated through crystal violet detection, reaching enhancement factors around 105. This study presents an innovative approach to synthesizing concave Au nanocrystals through the incorporation of selenium during a seeded growth process, offering insights into the strategic design of plasmonic nanostructures.

Fatty Amine-Mediated Synthesis of Hierarchical Copper Sulfide Nanoflowers for Efficient NIR-II Photothermal Conversion and Antibacterial Performance.

Non-noble metal photothermal materials have recently attracted increasing attention as unique alternatives to noble metal-based ones due to advantages like earth abundance, cost-effectiveness, and large-scale application capability. In this study, hierarchical copper sulfide (CuS) nanostructures with tunable flower-like morphologies and dimensional sizes are prepared via a fatty amine-mediated one-pot polyol synthesis. In particular, the addition of fatty amines induces a significant decrease in the overall particle size and lamellar thickness, and their morphologies and sizes could be tuned using different types of fatty amines. The dense stacking of nanosheets with limited sizes in the form of such a unique hierarchical architecture facilitates the interactions of the electromagnetic fields between adjacent nanoplates and enables the creation of abundant hot-spot regions, thus, benefiting the enhanced second near-infrared (NIR-II) light absorptions. The optimized CuS nanoflowers exhibit a photothermal conversion efficiency of 37.6%, realizing a temperature increase of nearly 50 °C within 10 min under 1064 nm laser irradiations at a power density of 1 W cm-2. They also exhibit broad-spectrum antibacterial activity, rendering them promising candidates for combating a spectrum of bacterial infections. The present study offers a feasible strategy to generate nanosheet-based hierarchical CuS nanostructures and validates their promising use in photothermal conversion, which could find important use in NIR-II photothermal therapy.

Improving Catalytic Performance via the Synergy of Tensile Lattice Strain and Plasmonic Enhancement in Defective AuPd@Pd Short Nanowires.

The synthesis of bimetallic nanocatalysts with strained crystal lattices has attracted considerable interest. This is because, beyond the electronic structure modifications realized through elemental doping, the strain effect offers an extra mechanism to fine-tune the electronic structures, thereby possibly improving the catalytic performances. We present a method for constructing defective AuPd@Pd short nanowires, achieved through a controlled galvanic replacement reaction between short AuCu nanowires and Pd precursors. Advanced structural analyses using spherical aberration-corrected transmission electron microscopy (AC-TEM) validated the expanded crystal lattice on the nanowire surface and also demonstrated pronounced plasmonic absorption in the UV-vis region. Leveraging both plasmonic absorption and strain effects, the AuPd@Pd short nanowires displayed a higher apparent rate constant compared to Pd nanoparticles. Integrating molecular dynamic simulations with density functional theory calculations revealed that the tensile strain on AuPd@Pd short nanowires benefited the catalytic activity by elevating the d-band center, thereby intensifying the adsorption of p-nitrophenol. The current research introduces a unique method for synthesizing noble metal nanocrystals with specific dimensions and elucidates the rational development of high-performance plasmonic nanocatalysts through synergistic exploitation of the beneficial strain effect.

Glutathione-Mediated Synthesis of Yolk-Shell AuAg Nanostructures Containing a Spherical Core and Cuboctahedral Skeletons and Their Applications in Plasmonic Catalysis.

Frame/skeleton-like nanostructures are of great value in plasmonic catalysis as a result of the synergetic structural advantages arising from both maximized surface atomic exposure and efficient incident light absorptions. Herein, we report the size-tunable fabrication of yolk-shell AuAg nanoparticles containing a spherical core and cuboctahedral skeletons (AuAg YSCNSs), together with the exploration of their applications for assisting the reduction of 4-nitrophenol (4-NP) under ultraviolet-visible (UV-vis) light irradiation. The use of glutathione (GSH) at an appropriate amount to mediate the galvanic replacement reaction between Au@Ag core-shell nanocubes and HAuCl4 is found to be crucial in regulating the shape evolution. Their sizes could be readily tuned by altering the edge lengths of Au@Ag core-shell nanocubes. When working as the photocatalyst assisting the reduction of 4-NP, the AuAg YSCNSs exhibit a higher apparent rate constant under UV-vis light irradiation. The current work demonstrates the feasibility to create skeleton-like noble metal nanocrystals with the shape largely deviated from that of the original template via the "top-down" carving strategy by introducing non-metallic surface doping, which could be potentially extended to other noble metals or alloys.

Boosting Electrocatalytic Oxidation of Formic Acid on Ir(IV)-Doped PdAg Alloy Nanodendrites with Sub-5 nm Branches.

The formic acid oxidation reaction (FAOR) represents an important class of small organic molecule oxidation and is central to the practical application of fuel cells. In this study, we report the fabrication of Ir(IV)-doped PdAg alloy nanodendrites with sub-5 nm branches via stepwise synthesis in which the precursors of Pd and Ag were co-reduced, followed by the addition of IrCl3 to conduct an in situ galvanic replacement reaction. When serving as the electrocatalyst for the FAOR in an acidic medium, Ir(IV) doping unambiguously enhanced the activity of PdAg alloy nanodendrites and improved the reaction kinetics and long-term stability. In particular, the carbon-supported PdAgIr nanodendrites exhibited a prominent mass activity with a value of 1.09 A mgPd-1, which is almost 2.0 times and 2.7 times that of their PdAg and Pd counterparts, and far superior to that of commercial Pt/C. As confirmed by the means of the DFT simulations, this improved electrocatalytic performance stems from the reduced overall barrier in the oxidation of formic acid into CO2 during the FAOR and successful d-band tuning, together with the stabilization of Pd atoms. The current study opens a new avenue for engineering Pd-based trimetallic nanocrystals with versatile control over the morphology and composition, shedding light on the design of advanced fuel cell electrocatalysts.

Seeded Growth of Gold-Copper Janus Nanostructures as a Tandem Catalyst for Efficient Electroreduction of CO2 to C2+ Products.

Gold-copper (Au-Cu) Janus nanostructures (Au-Cu Janus NSs) are successfully prepared using N-oleyl-1,3-propanediamine as capping agent and Cu(acac)2 as the precursor in a typical seeded growth strategy. By preferably depositing Cu atoms on one side of concave cubic Au seeds, the Cu part gradually grows larger as more Cu precursors are added, making the size tuning feasible in the range of 74-156 nm. When employed as an electrocatalyst for electrochemical CO2 reduction (CO2 RR), the Au-Cu Janus NSs display superior performance to Au@Cu core-shell NSs and Cu NPs in terms of C2+ products selectivity (67%) and C2+ partial current density (-0.29 A cm-2 ). Combined experimental verification and theoretical simulations reveal that CO spillover from Au sites to the nearby Cu counterparts would enhance CO coverage and thus promote C-C coupling, highlighting the unique structural advantages of the Au-Cu Janus NSs toward deep reduction of CO2 . The current work provides a facile strategy to fabricate tandem catalyst with a Janus structure and validates its structural advantages toward CO2 RR, which are of critical importance for the rational design of efficient CO2 RR catalyst.

Fabrication of Gold-Based "Sphere-on-Plate" Hybrid Nanostructures with Dual Plasmonic Absorptions Covering Visible and Near-Infrared II Windows via the Volmer-Weber Growth Mode.

We report a synthetic strategy to create gold(Au)-based "sphere-on-plate" hybrid nanostructures (SPHNSs). The surface doping of plate-like Au seeds with Pt/Ag atoms is found to be crucial to increase the lattice spacing, inducing island-like deposition of Au atoms via the Volmer-Weber growth mode. The resulting products are featured with the morphology that quasi-spherical nanoparticles are scattered over the nanoplates. Due to the presence of two distinctly dimensioned particles in one entity, the current Au-based SPHNSs exhibit unique dual plasmonic absorptions, where the visible absorbance centered at 546 nm is related to the size of the anchored particles. Arising from such a plasmonic advantage, the Au-based SPHNSs exhibit enhancement in photothermal conversion under laser irradiations at the wavelengths of both 808 and 1064 nm. The current work offers a feasible route to fabricate noble metal hybrid nanostructures involving zero-dimensional (0D) and two-dimensional (2D) structures, which could work as promising materials for photothermal conversion.

In Situ Crumpling of Gold Nanosheets into Spherical Three-Dimensional Architecture: Probing the Aggregation-Induced Enhancement in Photothermal Properties.

Assembling two-dimensional noble metal nanocrystals into a three-dimensional mesoporous structure is of great value to solve the re-stacking issue for the practical application, which still remains a challenging technique. Herein, we report the one-pot fabrication of gold (Au) nanostructures with a crumpled paper ball-like morphology (Au NCPBs). The success of current work relies on the use of glutathione to crumple the branched Au nanosheets formed during the early stage, into spherical three-dimensional architecture, where the nanosheets are assembled with a mesoporous structure without intimate contact. When working as the agent toward photothermal conversion, the Au NCPBs exhibit enhanced photothermal conversion efficiency (η = 19.9%), as compared to that of flat and wrinkled Au nanosheets. Such an enhancement should be owing to the aggregation-induced effect, where the shortened inter-sheet distance contributes to an increased coupling between the plasmon oscillations/fields of the interacting Au nanosheets. The present study offers a feasible strategy to create spherical architecture of crumpled Au nanosheets and validates their structural advantage in photothermal applications, which could be potentially extended to other metals or alloys.

Crumpled Versus Flat Gold Nanosheets: Temperature-Regulated Synthesis and Their Plasmonic and Catalytic Properties.

We report a high-yield synthesis of gold (Au) nanosheets with tunable size and surface morphology in the aqueous phase. In particular, crumpled and flat Au nanosheets with a thickness of ∼10 nm could be selectively produced in high purity when the reaction was conducted at room temperature and in an ice-water bath, respectively. Unlike Au nanoplates/nanoprisms in the form of well-defined triangles or hexagons documented in previous studies, the current products exhibit random in-plane branches or holes, together with wavy edges. Strong absorbance in the NIR region was observed for all the Au nanosheet products. When serving as electrocatalysts for the ethanol oxidation reaction, the current products exhibited an enhanced activity and operation stability, as compared to quasi-spherical counterparts.

Seed-Morphology-Directed Synthesis of Concave Gold Nanocrystals with Tunable Sizes.

We report the fabrication of concave gold (Au) nanocrystals with a set of morphologies and controlled sizes via seeded growth. Starting with Au seeds with a well-defined morphology and uniform size, cubic and rodlike Au nanocrystals with a noticeable concave feature could be successfully obtained, respectively. We also track the growth process and record the shape evolution process. The effect of several reaction parameters on product morphology, such as capping agent and concentration of Ag+, are systematically investigated. Their optical and electrochemical properties are investigated via UV-vis extinction spectroscopy and cyclic voltammetry, respectively. Compared to spherical counterparts, the current concave Au nanocrystals exhibit a noticeable red shift of the absorbance peak in UV-vis extinction spectra and characterized electrochemical behavior of stepped facets, illustrating the morphological advantage.

Constipation and risk of urinary incontinence in women: a meta-analysis.

INTRODUCTION AND HYPOTHESIS: Constipation is reported to be associated with urinary incontinence. However, the reported results have been inconsistent and contradictory. To evaluate the association between constipation and urinary incontinence in women, we performed a meta-analysis. METHODS: A comprehensive search based on PubMed, EMBASE, and the Cochrane Library was performed up to July 2018 for eligible studies in relation to the influence of constipation on urinary incontinence in women. A random-effect model was used to calculate the pooled odds risk (OR) and corresponding 95% confidence interval (CI). RESULTS: A total of 16 observational studies with 35,629 participants and 6054 urinary incontinence patients were identified in the meta-analysis. Constipation was significantly associated with the risk of urinary incontinence in women (OR 2.46, 95% CI 1.79-3.38). CONCLUSIONS: This meta-analysis suggests that constipation is significantly associated with urinary incontinence risk in women. However, further well-designed, large-scale prospective studies are needed to clarify the causality.

Dynamic Color-Switching of Plasmonic Nanoparticle Films.

The fast and reversible switching of plasmonic color holds great promise for many applications, while its realization has been mainly limited to solution phases, achieving solid-state plasmonic color-switching has remained a significant challenge owing to the lack of strategies in dynamically controlling the nanoparticle separation and their plasmonic coupling. Herein, we report a novel strategy to fabricate plasmonic color-switchable silver nanoparticle (AgNP) films. Using poly(acrylic acid) (PAA) as the capping ligand and sodium borate as the salt, the borate hydrolyzes rapidly in response to moisture and produces OH- ions, which subsequently deprotonate the PAA on AgNPs, change the surface charge, and enable reversible tuning of the plasmonic coupling among adjacent AgNPs to exhibit plasmonic color-switching. Such plasmonic films can be printed as high-resolution invisible patterns, which can be readily revealed with high contrast by exposure to trace amounts of water vapor.

Effects of bariatric surgery on pelvic floor disorders in obese women: a meta-analysis.

PURPOSE: Obesity is an established risk factor for pelvic floor disorders (PFD) but the effects of bariatric surgery on PFD are uncertain. This meta-analysis was conducted to evaluate the effects of bariatric surgery on PFD in obese women. METHODS: A systematic search of PubMed, Cochrane Library, CNKI and CBM databases up to October 2016 was performed, and studies reporting pre-operative and post-operative outcomes in obese women undergoing bariatric surgery were included. The Pelvic Floor Distress Inventory (PFDI-20), the Pelvic Floor Incontinence Questionnaire (PFIQ-7), the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire, Female Sexual Function Index and the International Consultation on Incontinence Questionnaire-Urinary Incontinence short form score were used for evaluating pelvic floor dysfunction after bariatric surgery. RESULTS: Eleven cohort studies were finally included. Pooled results revealed that bariatric surgery was associated with a significant improvement in PFD for obese women on the whole [PFDI-20: SMD = 0.89, 95% CI (0.44, 1.34), P < 0.001; PFIQ-7: SMD = 1.23, 95% CI (0.17, 2.29), P = 0.023]. In the subscale analysis, there was significant improvement in urinary incontinence and pelvic organ prolapse. However, no significant improvement was found in fecal incontinence and sexual function. CONCLUSIONS: Bariatric surgery is associated with significant improvement in urinary incontinence, and has a benefit on pelvic organ prolapse for obese women. However, there is no significant improvement in fecal incontinence and sexual function. Further multi-center, large-scale and longer-term randomized controlled trials are needed to confirm these results.

Synthesis of Ag nanocubes 18-32 nm in edge length: the effects of polyol on reduction kinetics, size control, and reproducibility.

This article describes a robust method for the facile synthesis of small Ag nanocubes with edge lengths controlled in the range of 18-32 nm. The success of this new method relies on the substitution of ethylene glycol (EG)--the solvent most commonly used in a polyol synthesis--with diethylene glycol (DEG). Owing to the increase in hydrocarbon chain length, DEG possesses a higher viscosity and a lower reducing power relative to EG. As a result, we were able to achieve a nucleation burst in the early stage to generate a large number of seeds and a relatively slow growth rate thereafter; both factors were critical to the formation of Ag nanocubes with small sizes and in high purity (>95%). The edge length of the Ag nanocubes could be easily tailored in the range of 18-32 nm by quenching the reaction at different time points. For the first time, we were able to produce uniform sub-20 nm Ag nanocubes in a hydrophilic medium and on a scale of ∼20 mg per batch. It is also worth pointing out that the present protocol was remarkably robust, showing good reproducibility between different batches and even for DEGs obtained from different vendors. Our results suggest that the high sensitivity of synthesis outcomes to the trace amounts of impurities in a polyol, a major issue for reproducibility and scale up synthesis, did not exist in the present system.

Transformation of Pd nanocubes into octahedra with controlled sizes by maneuvering the rates of etching and regrowth.

Palladium octahedra with controlled edge lengths were obtained from Pd cubes of a single size. The success of this synthesis relies on a transformation involving oxidative etching and regrowth. Because the {100} side faces of the Pd nanocubes were capped by Br(-) ions, Pd atoms were removed from the corners during oxidative etching, and the resultant Pd(2+) ions could be reduced and deposited back onto the nanocubes, but preferentially on the {100} facets. We could control the ratio of the etching and regrowth rates (R(etching) and R(regrowth)) simply by varying the amount of HCl added to the reaction solution. With a large amount of HCl, etching dominated the process (R(etching) ≫ R(regrowth)), resulting in the formation of Pd octahedra with an edge length equal to 70% of that of the cubes. In contrast, with a small amount of HCl, all of the newly formed Pd(2+) ions could be quickly reduced and deposited back onto the Pd cubes. In this case, R(etching) ≈ R(regrowth), and the resultant Pd octahedra had roughly the same volume as the starting cubes, together with an edge length equal to 130% of that of the cubes. When the amount of HCl was between these two extremes, we obtained Pd octahedra with intermediate edge lengths. This work not only advances our understanding of oxidative etching in nanocrystal synthesis but also offers a powerful means for controlling the shape and size of metal nanocrystals simply by adjusting the rates of etching and regrowth.

Facile synthesis of Pd-Ir bimetallic octapods and nanocages through galvanic replacement and co-reduction, and their use for hydrazine decomposition.

This article describes a facile synthesis of Pd-Ir bimetallic nanostructures in the forms of core-shell octapods and alloyed nanocages. The success of this synthesis relies on the use of Pd nanocubes as the sacrificial templates and interplay of two different processes: the galvanic replacement between an Ir precursor and the Pd nanocubes and the co-reduction of Pd(2+) and Ir(3+) by ethylene glycol. The galvanic replacement played a dominant role in the initial stage, through which Pd atoms were dissolved from the side faces whereas Ir atoms were deposited at the corner sites to generate Pd-Ir core-shell octapods. As the concentration of Pd(2+) in the reaction mixture was increased, co-reduction of Pd(2+) and Ir(3+) occurred in the late stage of synthesis. The resultant Pd and Ir atoms were deposited onto the octapods while the Pd atoms in the interiors continued to be etched away due to the galvanic replacement, finally leading to the formation of Pd-Ir alloyed nanocages. The octapods and nanocages were then evaluated as catalysts for the selective generation of hydrogen from the decomposition of hydrous hydrazine. The nanocages exhibited better selectivity for hydrogen generation than octapods (66% versus 29%), which can be attributed to the presence of an alloyed, porous structure on the surface.

[Expression of Eag1 K(+) channel in prostate cancer and its significance].

OBJECTIVE: To investigate the expression of the Eag1 K( +) channel in the prostate cancer (PCa) tissue, its correlation with the development and progression of PCa, and whether it could be a target for the diagnosis and treatment of PCa. METHODS: We used RT-PCR and immunohistochemistry to determine the mRNA and protein expressions of the Eag1 K(+) channel in the normal peritumoral tissue of androgen-dependent PCa (ADPCa) (group A) and androgen-independent PCa (AIPCa) (group B) as well as in the tumorous tissue of ADPCa (group C) and AIPCa (group D). RESULTS: The relative coefficients of the mRNA expression of the Eag1 K(+) channel were 0.265 +/- 0.413, 0.167 +/- 0.511, 2.673 +/- 2.988 and 2.815 +/- 2.901 in groups A, B, C and D, respectively, increased significantly in the latter two groups (P < 0.05). The positive rates of the protein expression of the Eag1 K (+) channel were significantly higher in groups C (88.9%) and D (86.7%) than in A (7.4%) and B (6.7%) (P < 0.05). CONCLUSION: The Eag1 K(+) channel might be involved in the pathophysiological processes of PCa, and is expected to be a valuable target for the diagnosis and treatment of PCa.

Construction of a 12-Phosphomolybdate-based Coordination Polymer@Crumpled Graphene Balls Composite as Anode for Lithium Batteries.

To address the poor electronic conductivity and easily dissolved in electrolyte of polyoxometalates (POMs), and considering the high electrical conductivity and configuration advantages of crumpled graphene balls (CGBs), herein, a series of POM-based coordination polymers [Cu(pyttz)2 ]PMo12 @CGB (n, n=1, 2, 3) were successfully synthesized, and electrochemical lithium storage performance and lithium ion diffusion kinetics were comprehensively investigated. Galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) study confirm that [Cu(pyttz)2 ]PMo12 @CGB (n, n=1, 2, 3) integrates the advantage of high electronic conductivity of CGB and excellent Li+ migration kinetics of POMs, which greatly ameliorates the electrochemical performances of POMs, among [Cu(pyttz)2 ]PMo12 @CGB (2) exhibits an excellent reversible specific capacity of around 941.4 mA h g-1 at 0.1 A g-1 after 150 cycles and admirable rate performance. This work will promote the development of POMCP anodes, thus fulfilling their potential in high-performance LIBs.

Controlling the size and morphology of Au@Pd core-shell nanocrystals by manipulating the kinetics of seeded growth.

This article reports a systematic study of the seed-mediated growth of Au@Pd core-shell nanocrystals with a variety of controlled sizes and morphologies. The key to the success of this synthesis is to manipulate the reaction kinetics by tuning a set of reaction parameters, including the type and concentration of capping agent, the amount of ascorbic acid used as the reducing agent, and the injection rate used for the precursor solution. Starting from Au nanospheres of 11 nm in diameter as the seeds, Au@Pd core-shell nanocrystals with a number of morphologies, including octahedra, concave octahedra, rectangular bars, cubes, concave cubes, and dendrites, could all be obtained by simply altering the reaction rate. For the first time, it was possible to generate Au@Pd nanocrystals with concave structures on the surfaces while their sizes were kept below 20 nm. In addition, the as-prepared Au@Pd nanocubes can be used as seeds to generate Au@Pd@Au and Au@Pd@Au@Pd nanocrystals with multishelled structures.