The Impact of Sleep Quality on Cognitive Function in Patients with Chronic Subjective Tinnitus.

BACKGROUND: The aim of this study was to explore the impact of sleep quality on cognitive function in patients with chronic subjective tinnitus. METHODS: The Pittsburgh Sleep Quality Index (PSQI) and the Montreal Cognitive Assessment Scale (MoCA) were used to assess sleep quality and cognitive function in patients with chronic subjective tinnitus, sleep disorder patients (SD), and normal controls (NC). The tinnitus evaluation questionnaire (TEQ) and tinnitus loudness were used to assess the severity in patients with chronic subjective tinnitus. Tinnitus patients were divided into two groups based on PSQI results: "tinnitus with sleep disorder (TwSD)" and "tinnitus without sleep disorder (TnSD)." The MoCA scores in TwSD and TnSD groups were compared with those in SD and NC groups, and the correlation between PSQI, TEQ, tinnitus loudness, and MoCA scores in subjective tinnitus patients were analyzed. RESULTS: Whether TwSD group or TnSD group, the MoCA score was significantly lower than those in the NC group and SD group. Meanwhile, there was no significant difference between TwSD and TnSD groups in MoCA score, and PSQI, TEQ, and tinnitus loudness were not significantly correlated with MoCA. CONCLUSION: Subjective tinnitus may be an independent risk factor for cognitive impairment. The underlying neural mechanisms between subjective tinnitus, sleep disorders, and cognitive impairment need to be further explored and clarified.

Effects of dietary supplementation of fermented Artemisia argyi on growth performance, slaughter performance, and meat quality in broilers.

Artemisia argyi (AA) is promising as a potential feed additive. Microbial fermentation is beneficial to the degradation of cell walls and the better release of bioactive compounds of AA. However, there are few reports on the application of fermented AA as a feed additive for broilers. The present study intended to evaluate the application value of fermented AA as a feed additive for broilers by examining the effects of the dietary supplementation of Aspergillus niger-fermented AA and unfermented AA on growth performance, slaughter performance, and meat quality of brokers. A total of 360 newly hatched (1-day-old) broilers with similar body weight were randomly divided into the following 5 groups: basal diet group as control (C) group, basal diet +3% unfermented AA (E1) group, basal diet + 1% fermented AA (E2) group, basal diet + 3% fermented AA (E3) group, basal diet + 5% fermented AA (E4) group. Each group included 6 replicates with 12 broilers per replicate, and the feeding trail lasted for 48 d. Body weight and feed intake were recorded every 2 wk, and the feed gain ratio was calculated to assess growth performance. At 42 d, 6 broilers from each group were slaughtered, and the carcass traits were calculated. The results showed that compared with the control group, Aspergillus Niger could effectively destroy AA fiber, which contributed to better release of AA bioactive compounds. Moreover, dietary supplementation with AA could improve the growth performance of broilers (P < 0.05), and the effect of fermented AA was better than unfermented AA, especially 3% fermented AA. From 28 to 42 d, compared with the control group, the average daily gain of broilers in the group supplementation with 3% fermented AA was significantly increased (P < 0.05), and the feed-to-gain ratio was decreased (P < 0.05). At 42 d, the dressing percentage, half-eviscerated carcass percentage, eviscerated carcass percentage, and breast muscle percentage of broilers in the groups of 1, 3, and 5% fermented AA diets were significantly improved (P < 0.05), and the thigh muscle percentage of broilers in the group with 3% fermented AA diets was significantly improved (P < 0.05). Meanwhile, the meat quality of broilers in the group with fermented AA diets was also significantly improved. Birds in AA groups had higher a* value and lower shear force of breast muscle, especially the group supplementation with 3% fermented AA (P < 0.05). In conclusion, fermented AA has good application value as a potential feed additive for broilers, dietary supplementation of fermented AA can improve the production performance and meat quality of broiler chickens, of which 3% fermented AA is more effective.

Controlled Preparation of Highly Stretchable, Crack-Free Wrinkled Surfaces with Tunable Wetting and Optical Properties.

Constructing wrinkles by utilizing strain-driven surface instability in film-substrate systems is a general method to prepare micronano structures, which have a wide range of applications in smart surfaces and devices such as flexible electronics, reversible wetting, friction, and optics. However, cracks generated during the preparation and use process significantly affect the uniformity of wrinkled surfaces and degrade the functional properties of the film devices. The realization of crack-free wrinkles with high stretchability in hard film systems is still a great challenge. Here, we report on a facile technique for controllable preparation of large-area, highly stretchable, crack-free wrinkled surfaces by ultraviolet ozone (UVO) treatment of Ecoflex. The thickness dependence of the wrinkles and the in situ wrinkling process during mechanical loading are investigated. The wrinkles including striped, labyrinth-like, herringbone, and transitional structures are controllable by changing strain mode (uniaxial or biaxial), loading history (simultaneous or sequential), strain anisotropy, and gradient loading. The wrinkled surfaces obtained using UVO-treated Ecoflex have tunable wetting and optical properties and can maintain excellent mechanical stability under large strains. This study provides a facile method for the preparation of large-area, crack-free wrinkles, which is simple, fast, low-cost, and robust. The resulting wrinkled surfaces remain stable under high stretching, which is beneficial for many practical applications, especially in the cases of large strains.

A cross-scale honeycomb architecture-based flexible piezoresistive sensor for multiscale pressure perception and fine-grained identification.

Trade-off between sensitivity and the pressure sensing range remains a great challenge for flexible pressure sensors. Micro-nano surface structure-based sensors usually show high sensitivity only in a limited pressure regime, while porous structure-based sensors possess a broad pressure-response range with sensitivity being sacrificed. Here, we report a design strategy based on a cross-scale architecture consisting of a microscale tip and macroscale base, which provides continuous deformation ability over a broad pressure regime (10-4-104 kPa). The cross-scale honeycomb architecture (CHA)-based piezoresistive sensor exhibits an excellent sensitivity over a wide pressure range (0.5 Pa-0.56 kPa: S1 ∼ 27.97 kPa-1; 0.56-20.40 kPa: S2 ∼ 2.30 kPa-1; 20.40-460 kPa: S3 ∼ 0.13 kPa-1). As a result, the CHA-based sensor shows multiscale pressure perception and fine-grained identification ability from 0.5 Pa to 40 MPa. Additionally, the cross-scale architecture will be a general structure to design other types of sensors for highly sensitive pressure perception in a wide pressure range and its unit size from microscale to macroscale is beneficial for large-scale preparation, compared with micro-nano surface structures or internal pores.

Confined-Enhanced Raman Spectroscopy.

In 1997, the discovery of single molecule-surface enhanced Raman spectroscopy (SM-SERS) rekindled broad interests owing to its ultrahigh enhancement factor up to the 1014-1015 level. However, regretfully, the advantage of SM-SERS with an ultralow detection limit has not yet been fully utilized in commercialized applications. Here, we report a strategy, which we name confined-enhanced Raman spectroscopy, in which the overall Raman properties can be remarkably improved with in situ-formed active nanoshell on the surface of silver or gold nanoparticles. The nanoshell can confine and anchor molecules onto the surface of plasmonic nanoparticles and avoid desorption from hot spots so that the "on and off" blinking effect can be eliminated. It is the first time the single-molecule detection of analytes with super sensitivity, high stability, and reproducibility based on gold nanoparticles has been realized. In addition, this strategy is suitable for SERS detection in diverse molecule systems, including biomedical diagnosis, catalytic reaction, etc.

Tunable Magnetic Domain Patterns in Thickness-Gradient Nickel Films on Flexible PDMS Substrates.

Flexible magnetoelectronic devices (based on magnetic films) have great application prospects in the fields of information storages, bionic robotics, and electronic skins. The intrinsic stress and external loading are very important to modulate the structures and properties of flexible magnetic films due to the magnetoelastic coupling effect. Here, we report on tunable magnetic domain patterns in thickness-gradient nickel (Ni) films deposited on flexible polydimethylsiloxane substrates. It is found that stripe magnetic domains spontaneously form in the Ni films and their sizes increase with the film thickness. The internal stress evolves from tensile to compressive states with decreasing film thickness, leading to the formation of cracks in thicker regions and wrinkles in thinner regions. Meanwhile, the orientations of stripe magnetic domains change from the gradient direction to the orthogonal direction. The structural features, evolution behaviors, and physical mechanisms of the cracks, wrinkles, and magnetic domains are analyzed based on the stress theory and magnetoelastic coupling. Periodic gradient Ni films with large-scale regulations of stripe magnetic domains are also realized by masking of copper grids. This study helps to better understand the magnetoelastic coupling effect in gradient flexible magnetic films and provides a technique to modulate anisotropic magnetic properties by designing specific film systems.

Indium selenide/silver phosphate hollow microsphere S-scheme heterojunctions for photocatalytic hydrogen production with simultaneous degradation of tetracycline.

Designing heterojunction photocatalysts with strong interfacial interactions is an effective way to reduce the recombination of photogenerated charge carriers. Here, silver phosphate (Ag3PO4) nanoparticles are coupled with hollow flower-like indium selenide (In2Se3) microspheres by a facile Ostwald ripening and in-situ growth method, resulting in the construction of In2Se3/Ag3PO4 hollow microsphere step-scheme (S-scheme) heterojunction with a large contact interface. The flower-like In2Se3 with hollow and porous structure provides a large specific surface area and numerous active sites for photocatalytic reactions to take place. The photocatalytic activity was tested by measuring the hydrogen evolution from antibiotic wastewater, and the H2 evolution rate of In2Se3/Ag3PO4 reached 4206.4 µmol g-1h-1 under visible light, which is approximately 2.8 times greater than that of In2Se3. In addition, the amount of tetracycline (TC) degradation when it was used as a sacrificial agent is about 54.4% after 1 h. On the one hand, Se-P chemical bonds act as electron transfer channels in the S-scheme heterojunctions, which can facilitate the migration and separation of photogenerated charge carriers. On the other hand, the S-scheme heterojunctions can retain the useful holes and electrons with higher redox capacities, which is very favorable for the generation of more •OH radicals and the photocatalytic activity is greatly enhanced. This work provides an alternative design approach for photocatalysts toward hydrogen evolution in antibiotic wastewater.

Personality Traits and Tinnitus Distress: Results Based on Patients with Tinnitus in China.

Background: Due to the socio-cultural differences between China and other countries, which may affect the development of an individual's personality and behavior, it is necessary to explore the relationship between personality traits and tinnitus distress in the context of China's socio-cultural background. Methods: The Tinnitus Handicap Inventory and the Eysenck Personality Questionnaire Short Scale Chinese version were used to explore the influence of personality traits on tinnitus distress in Chinese patients with tinnitus. Results: The results were not entirely consistent with previous studies from other countries. First, extroversion was significantly higher in patients with bothersome tinnitus, both in acute and chronic conditions. Second, the personality traits that affected the patients with bothersome tinnitus were different in different conditions. Finally, the tridimensional personality structure, high psychoticism / normal extroversion / normal neuroticism, was significantly higher in people with bothersome tinnitus. Furthermore, the difference became more obvious with a prolonged disease course. Conclusions: This study suggested that the relationship between personality traits and tinnitus distress in Chinese patients with tinnitus was not the same as in other countries. "High psychoticism / normal extroversion / normal neuroticism" may be a risk factor for chronic bothersome tinnitus in China.

Rapid and ultrasensitive solution-based SERS detection of drug additives in aquaculture by using polystyrene sulfonate modified gold nanobipyramids.

In recent years, surface-enhanced Raman spectroscopy (SERS) has been widely used in various fields for the rapid detection of trace-level molecular targets. In this study, we have developed a simple and effective solution-based SERS protocol to improve the activity for the detection of cationic dye molecules in aquaculture. The polystyrene sulfonate functionalized gold nanobipyramids (PSS-Au BPs) were synthesized from the cetyltrimethylammonium bromide (CTAB) reaction system followed by the ligand exchange process. The halide ions-induced aggregation of PSS-Au BPs was carried out by using four type of different salts such as NaCl, NaBr, MgCl2 and MgSO4 to investigate their influence on the SERS activity. The results demonstrate that the ionic strength of the solution has an important impact on the colloidal stability and SERS activity. The PSS-Au BPs show an improved SERS sensitivity at lower concentrations of the aggregating agents in solution-based SERS by detecting the crystal violet (CV) molecules with a limit of detection (LOD) to 3.28 × 10-11 M. Furthermore, to demonstrate the generality of our proposed strategy, trace amounts of three more dyes such as malachite green (MG), methylene blue (MB), and rhodamine 6G (R-6G), as well as other molecules such as thiram and bisphenol-S were also detected. This protocol not only provides a method for rapid on-site detection of trace-level molecules but can also be applied to other SERS-based analysis.

Controllable Buckle Delaminations in Polymer-Supported Periodic Gradient Films by Mechanical Compression.

Surface instabilities including wrinkles and buckle-delaminations are widespread in nature and can be found in a wide range of practical applications. Compared with the homogeneous wrinkle mode, the buckle-delaminations are spontaneously stress-localized, and their initiation positions and geometrical parameters are hardly precisely controlled by a simple method. Here, we report on the controllable buckle-delaminations in periodic thickness-gradient metal films on polydimethylsiloxane (PDMS) substrates by uniaxial mechanical compression. It is found that a periodic thickness-gradient film is spontaneously formed by masking a copper grid during deposition. The released mechanical strain tends to concentrate in thinner film regions, resulting in the restricted growth of buckle-delaminations. The geometrical features, evolutional behaviors, and underlying physical mechanisms of such buckle-delaminations are analyzed and discussed in detail based on the buckling model and finite element simulations. This work would provide a better understanding of the restricted buckle-delaminations in heterogeneous film-substrate systems and controllable fabrication of ordered structural arrays by copper grid masking and mechanical loading.

[An analyzation on the characterization of frequency tuning of vestibular evoked myogenic potential in patients with unilateral vestibular hypofunction].

Objective: To explore the value of adding 1 kHz cervical vestibular evoked myogenic potential（cVEMP） and ocular vestibular evoked myogenic potential（oVEMP） in the auxiliary diagnosis of unilateral vestibular hypofunction. Methods:A retrospective analysis of 84 patients with unilateral vestibular hypofunction receiving two or more vestibular function tests was conducted,29 cases of unilateral Ménière's disease, 27 cases of benign paroxysmal positional vertigo （BPPV）, 8 cases of idiopathic sudden sensorineural hearing loss （ISSHL） with vertigo, and 20 cases of ISSHL without vertigo were included. SPSS 25.0 software was used for statistical analysis to observe the difference of frequency amplitude ratio （FAR） at 500 Hz/1 kHz of cVEMP and oVEMP between the experimental and control groups. Results:①The cVEMP elicitation rates were 95.24% （80/84） and 98.81% （83/84） for 500 Hz and 1 kHz, respectively; and the oVEMP elicitation rates were 78.57% （66/84） and 91.67% （77/84） for 500 Hz and 1 kHz, respectively. ②Except for the lateral difference of FAR in oVEMP of the posterior semicircular canal BPPV group and cVEMP of the horizontal semicircular canal BPPV group （P<0.05）, no significant lateral difference was observed in the other disease groups （P>0.05）. Conclusion:In patients with unilateral vestibular hypofunction, cVEMP and oVEMP showed different frequency tuning changes in different semicircular canal BPPV groups. Additionally, 1 kHz cVEMP and oVEMP as regular stimulation frequencies in clinical test, which has certain clinical reference significance for determining the diagnosis and prognosis of BPPV on the weak ear and in different semicircular canal involvement.

Prognostic Factors Influencing the Tinnitus Improvement After Idiopathic Sudden Sensorineural Hearing Loss Treatment.

PURPOSE: Logistic regression analysis was used to explore the factors that influence tinnitus improvement after idiopathic sudden sensorineural hearing loss (ISSNHL) treatment. MATERIALS AND METHODS: In this retrospective study, 137 ISSNHL patients with tinnitus were recruited at the Sun Yatsen Memorial Hospital of Sun Yat-sen University, China. They underwent audiological examinations, vestibular assessments, tinnitus examinations, a Tinnitus Handicap Inventory (THI) assessment and ISSNHL treatments. Logistic regression analysis was performed to investigate factors that affected tinnitus improvement. RESULTS: Participants were divided into an effective group (73 patients) and noneffective group (64 patients) according to THI scores before and after treatment. The effective group had better averaged hearing threshold than the noneffective group (effective group vs. noneffective group: 74.47 vs. 87.66 dB HL; t = 3.03, p < 0.05). Additionally, before intervention there were significant difference in profound audiogram configuration (effective group vs. noneffective group: 17.81% vs. 46.88%, x2 = 23.63; p < 0.001), mid tinnitus pitch (effective group vs. noneffective group: 19.18% vs. 35.94%, x2 = 6.58; p = 0.037) and mean THI scores (effective group vs. noneffective group: 57.07 ± 22.27 vs. 36.78 ± 24.41, t = -5.09, p < 0.001) between the effective and noneffective tinnitus groups. Logistic regression analysis showed that audiogram configurations (profound audiogram: OR = 0.10, 95% CI 0.01-0.72, p = 0.022), tinnitus pitch (mid tinnitus pitch: OR = 0.16, 95% CI 0.05-0.57, p = 0.004) and THI scores (OR = 1.05, 95% CI 1.03-1.07, p < 0.001) were independent factors associated with tinnitus improvement. CONCLUSION: Audiogram configuration, tinnitus pitch, and THI scores before intervention appear to be predictive of the effectiveness of acute tinnitus improvement following ISSNHL treatment.

[Thermal Environment Evolution and Response Mechanism of Urban Sprawl Based on Multi-source Data].

Improving the urban thermal environment and improving the quality of human settlements are important prerequisites for creating ecologically livable cities. The current research on the relationship between urban expansion and the thermal environment is mostly based on remote sensing data, and the application of multi-source data is weak. Here, we selected the Xi'an metropolitan core area, measured the urban expansion and temporal and spatial evolution of the thermal environment based on Landsat remote sensing images in 2010 and 2020, and used multi-source data, such as interest points and the Baidu thermal index, to study the response mechanism of the urban thermal environment through geoscience statistical analysis methods. The results showed that:① the construction land in the study area had expanded by 200.84 km2, and the area and intensity showed that "the center and the periphery are weaker, and the difference between the two" characteristics, and the expansion mode was mainly edge type and infill type. ② Between 2010 and 2020, the overall thermal environment in the study area deteriorated, and the area of the heat island area increased by 282.65 km2. The spread of the heat island area was in the same direction as the urban expansion, and the distribution pattern evolved from "southeast-northwest" to "northeast-southwest;" however, the average temperature in the central area of the city decreased 1.09℃. ③ Urban expansion was strongly positively correlated with the deterioration of the urban thermal environment. The expansion of urban space had a contribution rate of 60.40% to the deterioration of the thermal environment, and various socio-economic factors had a weaker effect, with an overall contribution rate of 39.60%. The vegetation water body had an obvious cooling effect; under the influence of multiple factors, the surface temperature increased by 0.241 units. In the process of urban expansion, changes in surface parameters and two-dimensional urban morphology were still the main factors for thermal environment changes, whereas three-dimensional morphology had a small effect on the warming of social and economic activities, and the contribution of water bodies and vegetation to cooling was prominent.

Tailoring Ordered Wrinkle Arrays for Tunable Surface Performances by Template-Modulated Gradient Films.

Complex wrinkled microstructures are ubiquitous in natural systems and living bodies. Although homogeneous wrinkles in film-substrate bilayers have been extensively investigated in the past 2 decades, tailoring heterogeneous wrinkles by a facile method is still a challenge. Here, we report on the controllable heterogeneous wrinkles in template-modulated thickness-gradient metal films sputter-deposited on polydimethylsiloxane substrates. It is found that the stress of the gradient film is strongly position-dependent and the wrinkles are always restricted in thinner film regions. The morphological characteristic and formation mechanism of the heterogeneous wrinkles are analyzed and discussed in detail based on the stress theory. Ordered wrinkle arrays are achieved by adjusting the deposition time, copper grid period, template shape, and lifting height. The surface performances (e.g., the friction property) are well controlled by the wrinkle arrays. This work could promote better understanding of the spontaneously heterogeneous wrinkles in template-modulated gradient films and controllable fabrication of various wrinkle arrays by independently tuning film deposition conditions and template parameters.

Non-Fluorinated Flexible Superhydrophobic Surface with Excellent Mechanical Durability and Self-Cleaning Performance.

Although plenty of superhydrophobic surfaces have been developed owing to their tremendous potential applications, it is still a great challenge for the superhydrophobic surfaces to possess environmental friendliness, biocompatibility, and mechanical durability simultaneously. Herein, a non-fluorinated flexible superhydrophobic surface was designed by constructing a film-substrate system with labyrinth-like wrinkles combining an intrinsically hydrophobic Zn film and a polydimethylsiloxane (PDMS) substrate. Excellent superhydrophobicity with a contact angle up to 168.5° and a slide angle as low as 0° has been achieved on the Zn/PDMS surface, which is attributed to the micro-/nano-textured structures of the labyrinth-like wrinkles, providing sufficient air pockets to form a stable Cassie-Baxter state. Furthermore, the Zn/PDMS surface retains excellent superhydrophobicity under stretching, bending, and twisting mechanical deformation up to 500 cycles due to the stability of the micro-/nano-textured structures of the labyrinth-like wrinkles protected by the fantastic self-healing ability of the micro-cracks. Additionally, the Zn/PDMS superhydrophobic surface possesses an outstanding self-cleaning performance for various contaminants. The present work provides a valuable routine to design non-fluorinated flexible superhydrophobic surfaces with superb mechanical durability and self-cleaning property as promising functional layers for flexible electronics, wearable devices, biomedical engineering, and so forth.

Two-dimensional magneto-photoconductivity in non-van der Waals manganese selenide.

Deficient intrinsic species and suppressed Curie temperatures (Tc) in two-dimensional (2D) magnets are major barriers for future spintronic applications. As an alternative, delaminating non-van der Waals (vdW) magnets can offset these shortcomings and involve robust bandgaps to explore 2D magneto-photoconductivity at ambient temperature. Herein, non-vdW α-MnSe2 is first delaminated as quasi-2D nanosheets for the study of emerging semiconductor, ferromagnetism and magneto-photoconductivity behaviors. Abundant nonstoichiometric surfaces induce the renormalization of the band structure and open a bandgap of 1.2 eV. The structural optimization strengthens ferromagnetic super-exchange interactions between the nearest-neighbor Mn2+, which enables us to achieve a high Tc of 320 K well above room temperature. The critical fitting of magnetization and transport measurements both verify that it is of quasi-2D nature. The above observations are evidenced by multiple microscopic and macroscopic characterization tools, in line with the prediction of first-principles calculations. Profiting from the negative magnetoresistance effect, the self-powered infrared magneto-photoconductivity performance including a responsivity of 330.4 mA W-1 and a millisecond-level response speed are further demonstrated. Such merits stem from the synergistic modulation of magnetic and light fields on photogenerated carriers. This provides a new strategy to manipulate both charge and spin in 2D non-vdW systems and displays their alluring prospects in magneto-photodetection.

Polymer-buried van der Waals magnets for promising wearable room-temperature spintronics.

The demand for high-performance spintronic devices has boosted intense research on the manipulation of magnetism in van der Waals (vdW) magnets. Despite great efforts, robust ferromagnetic transitions above room temperature still face significant hurdles. Strain engineering can reversibly regulate magnetic exchange, but the degree of regulation is still impractical for most magnetic applications. Hereby we employ a large-strain transferrer to produce tunable strains of up to 4.7%, which induces authentic room-temperature ferromagnetism in large-area Fe3GeTe2 nanoflakes with 20-fold improvement in magnetization. The record increment of the Curie temperature (TC) of well above 400 K originates from the strain-enhanced magnetic anisotropy and excellent magnetoelastic coupling. The correlation between the emerging ferromagnetism and Raman spectral evolution is also established, which complements well the TC phase diagram in a large-strain region. In addition, an unusual exchange bias effect with a vertical magnetization shift is tracked for the first time upon bending, which reveals the hidden competition between antiferromagnetic and ferromagnetic coupling. The reversible strain manipulation of single-domain ferromagnetic order in a single nanoflake further opens up a route to develop low-power wearable spintronic devices. The findings here provide vast opportunities to exploit the possibility of practical applications of more vdW magnets.

Switchable Binding Energy of Ionic Compounds and Application in Customizable Ligand Exchange for Colloid Nanocrystals.

The ability to engineer the surface ligands or adsorbed molecules on colloid nanocrystals (NCs) is important for various applications, as the physical and chemical properties are strongly affected by the surface chemistry. Here, we develop a facile and generalized ionic compound-mediated ligand-exchange strategy based on density functional theory calculations, in which the ionic compounds possess switchable bonding energy when they transfer between the ionized state and the non-ionized state, hence catalyzing the ligand-exchange process. By using an organic acid as the intermediate ligand, ligands such as oleylamine, butylamine, polyvinylpyrrolidone, and poly(vinyl alcohol) can be freely exchanged on the surface of Au NCs. Benefiting from this unique ligand-exchange strategy, the ligands with strong bonding energy can be replaced by weak ones, which is hard to realize in traditional ligand-exchange processes. The ionic compound-mediated ligand exchange is further utilized to improve the catalytic properties of Au NCs, facilitate the loading of nanoparticles on substrates, and tailor the growth of colloid NCs. These results indicate that the mechanism of switchable bonding energy can be significantly expanded to manipulate the surface property and functionalization of NCs that have applications in a wide range of chemical and biomedical fields.

Solution-Based SERS Detection of Weak Surficial Affinity Molecules Using Cysteamine-Modified Au Bipyramids.

To achieve ultrasensitive detection of trace targets through solution-based surface-enhanced Raman spectroscopy (SERS), direct adsorption of the target molecules on a SERS-active surface is vital. In this work, cetyltrimethylammonium bromide (CTAB)-capped gold nano-bipyramids (Au BPs) with different aspect ratios (ARs) are prepared and the surface is successfully modified by a simple ligand exchange method. Cysteamine-capped gold nano-bipyramids (cyst-Au BPs) are obtained by means of replacement of CTAB by cysteamine using Au-S covalent bonding and applied in the solution-based SERS detection of different pigment molecules, which always have weak affinity to the gold surface. The hydrogen bonding between the pigment molecule and cysteamine causes the aggregation of Au BPs to generate local electromagnetic field enhancement. The influence of the AR and concentration of Au BPs on SERS properties is investigated. The SERS detection of weak-affinity molecules to an extremely low limit shows that the cyst-Au BPs are highly sensitive compared to CTAB-capped Au BPs. The limit of detection (LOD) of allura red as low as 0.1 ppb and that of sunset yellow as low as 1 ppb show that the proposed strategy has many advantages due to its simplicity and fast and rapid detection for the sensitivity analysis of weak-affinity molecules.

Insight of the Influence of Magnetic-Field Direction on Magneto-Plasmonic Interfaces for Tuning Photocatalytical Performance of Semiconductors.

Boosting photocatalytic performance via external fields is an alternative and effective solution for improving the application performance of existing photocatalysts. Herein, using α-Fe2O3-decorated TiO2 nanotube arrays as a model, we demonstrate the influence of magnetic field (MF)-direction on the photogenerated charge-carrier transfer behavior at plasmonic metal/semiconductor interfaces. For the first time, the photocatalytic activity is also found to correlate with the plasmonic metal species while applying an external MF. As verified by first-principles calculations, the spin-orbit coupling of metal contributes to the charge-carrier transfer. To highlight the anisotropic MF-tuning effect in practical applications, the as-prepared architecture is applied for photocatalysis-triggered drug delivery. The delivery rate can be remarkably accelerated by ∼38% under a tiny MF (0.4 T) with the proper direction. The findings in this research may provide new insight into designing semiconductor architectures for boosting the photocatalytical performance in an external MF.