Biocompatible Silica-Coated Europium-Doped CsPbBr3 Nanoparticles with Luminescence in Water for Zebrafish Bioimaging.

Cesium lead halide (CsPbX3, X = Br, Cl, and I) nanocrystals (NCs) are widely concerned and applied in many fields due to the excellent photoelectric performance. However, the toxicity of Pb and the loss of luminescence in water limit its application in vivo. A stable perovskite nanomaterial with good bioimaging properties is developed by incorporating europium (Eu) in CsPbX3 NCs followed with the surface coating of silica (SiO2) shell (CsPbX3:Eu@SiO2). Through the surface coating of SiO2, the luminescence stability of CsPbBr3 in water is improved and the leakage of Pb2+ is significantly reduced. In particular, Eu doping inhibits the photoluminescence quantum yield reduction of CsPbBr3 caused by SiO2 coating, and further reduces the release of Pb2+. CsPbBr3:Eu@SiO2 nanoparticles (NPs) show efficient luminescence in water and good biocompatibility to achieve cell imaging. More importantly, CsPb(ClBr)3:Eu@SiO2 NPs are obtained by adjusting the halogen components, and green light and blue light are realized in zebrafish imaging, showing good imaging effect and biosafety. The work provides a strategy for advanced perovskite nanomaterials toward biological practical application.

FBXL10 regulates cardiac dysfunction in diabetic cardiomyopathy via the PKC ß2 pathway.

Diabetic cardiomyopathy (DCM) is a condition associated with significant structural changes including cardiac tissue necrosis, localized fibrosis, and cardiomyocyte hypertrophy. This study sought to assess whether and how FBXL10 can attenuate DCM using a rat streptozotocin (STZ)-induced DCM model system. In the current study, we found that FBXL10 expression was significantly decreased in diabetic rat hearts. FBXL10 protected cells from high glucose (HG)-induced inflammation, oxidative stress, and apoptosis in vitro. In addition, FBXL10 significantly activated PKC ß2 signaling pathway in H9c2 cells and rat model. The cardiomyocyte-specific overexpression of FBXL10 at 12 weeks after the initial STZ administration attenuated oxidative stress and inflammation, thereby reducing cardiomyocyte death and preserving cardiac function in these animals. Moreover, FBXL10 protected against DCM via activation of the PKC ß2 pathway. In conclusion, FBXL has the therapeutic potential for the treatment of DCM.

Assessment of morphometry of pulmonary acini in mouse lungs by nondestructive imaging using multiscale microcomputed tomography.

Establishing the 3D architecture and morphometry of the intact pulmonary acinus is an essential step toward a more complete understanding of the relationship of lung structure and function. We combined a special fixation method with a unique volumetric nondestructive imaging technique and image processing tools to separate individual acini in the mouse lung. Interior scans of the parenchyma at a resolution of 2 µm enabled the reconstruction and quantitative study of whole acini by image analysis and stereologic methods, yielding data characterizing the 3D morphometry of the pulmonary acinus. The 3D reconstructions compared well with the architecture of silicon rubber casts of mouse acini. The image-based segmentation of individual acini allowed the computation of acinar volume and surface area, as well as estimation of the number of alveoli per acinus using stereologic methods. The acinar morphometry of male C57BL/6 mice age 12 wk and 91 wk was compared. Significant increases in all parameters as a function of age suggest a continuous change of the lung morphometry, with an increase in alveoli beyond what has been previously viewed as the maturation phase of the animals. Our image analysis methods open up opportunities for defining and quantitatively assessing the acinar structure in healthy and diseased lungs. The methods applied here to mice can be adjusted for the study of similarly prepared human lungs.

Heteroatom-Driven Coordination Fields Altering Single Cerium Atom Sites for Efficient Oxygen Reduction Reaction.

For current single-atom catalysts (SACs), modulating the coordination environments of rare-earth (RE) single atoms with complex electronic orbital and flexible chemical states is still limited. Herein, cerium (Ce) SAs supported on a P, S, and N co-doped hollow carbon substrate (Ce SAs/PSNC) for the oxygen reduction reaction (ORR) are reported. The as-prepared Ce SAs/PSNC possesses a half-wave potential of 0.90 V, a turnover frequency value of 52.2 s-1 at 0.85 V, and excellent stability for the ORR, which exceeds the commercial Pt/C and most recent SACs. Ce SAs/PSNC-based liquid zinc-air batteries (ZABs) exhibit a high and stable open-circuit voltage of 1.49 V and a maximum power density of 212 mW cm-2 . As the catalyst of the air cathode, it also displays remarkable performance in flexible electronic devices. Theoretical calculations reveal that the introduction of S and P sites induces significant electronic modulations to the Ce SA active sites. The P and S dopings promote the electroactivity of Ce SAs and improve the overall site-to-site electron transfer within the Ce SAs/PSNC. This work offers a unique perspective for modulating RE-based SACs in a complex coordination environment toward superior electrocatalysis and broad applications in energy conversion and storage devices.

Laves phase Ir2Sm intermetallic nanoparticles as a highly active electrocatalyst for acidic oxygen evolution reaction.

Rare earth (RE) intermetallic nanoparticles (NPs) are significant for fundamental explorations and promising for practical applications in electrocatalysis. However, they are difficult to synthesize because of the unusually low reduction potential and extremely high oxygen affinity of RE metal-oxygen bonds. Herein, intermetallic Ir2Sm NPs were firstly synthesized on graphene as a superior acidic oxygen evolution reaction (OER) catalyst. It was verified that intermetallic Ir2Sm is a new phase belonging to the C15 cubic MgCu2 type in the Laves phase family. Meanwhile, intermetallic Ir2Sm NPs achieved a mass activity of 1.24 A mgIr-1 at 1.53 V and stability of 120 h at 10 mA cm-2 in 0.5 M H2SO4 electrolyte, which corresponds to a 5.6-fold and 12-fold enhancement relative to Ir NPs. Experimental results together with density functional theory (DFT) calculations show that in the structurally ordered intermetallic Ir2Sm NPs, the alloying of Sm with Ir atoms modulates the electronic nature of Ir, thereby reducing the binding energy of the oxygen-based intermediate, resulting in faster kinetics and enhanced OER activity. This study provides a new perspective for the rational design and practical application of high-performance RE alloy catalysts.

Ternary Rare Earth Alloy Pt3-xIrxSc Nanoparticles Modulate Negatively Charged Pt via Charge Transfer To Facilitate pH-Universal Hydrogen Evolution.

Rare earth (RE) elements possess electronic configurations that can provide additional pathways for tailoring the electronic structures of active elements through alloying, making it an important area of exploration in electrocatalysis. However, the large negative redox potential between RE and Pt has hindered the development of RE nanoalloys. In this study, a solid-phase synthesis strategy was employed to synthesize ternary Pt3-xIrxSc nanoparticles (NPs). By leveraging the electronegativity difference between Pt (2.28), Ir (2.20), and Sc (1.36), a charge-balance strategy was implemented to stabilize and enhance the catalytic performance of the alloy. The electron transfer from Sc to Pt/Ir results in the latter being negatively charged, and the Ir modifies the electron density of Pt, enabling favorable adsorption of active H species during the hydrogen evolution reaction (HER). Pt2IrSc exhibits enhanced HER activity at all pH values, achieving low overpotentials at 10 mA cm-2 of only 13, 18, and 25 mV in 0.5 M H2SO4, 1 M PBS, and 1 M KOH, respectively. This electrocatalyst also exhibits robust electrocatalytic stability even after 20,000 cycles. This work represents an application of the charge balance strategy to RE nanoalloys, and it is expected to inspire the design and synthesis of highly reactive RE nanoalloys.

Short-term effects of air pollution and weather changes on the occurrence of acute aortic dissection in a cold region.

Background: Air pollution and severe weather conditions can adversely affect cardiovascular disease emergencies. Nevertheless, it remains unclear whether air pollutants and low ambient temperature can trigger the occurrence of acute aortic dissection (AAD) in cold regions. Methods: We applied a retrospective analysis to assess the short-term effects of air pollution and ambient temperature on the occurrence of AAD in Harbin, China. A total of 564 AAD patients were enrolled from a major hospital in Harbin between January 1, 2017, and February 5, 2021. Weather condition data and air pollutant concentrations, including fine particulate matter smaller than 10 µm (PM10) and 2.5 µm in diameter (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3), were collected every day. Conditional logistic regressions and correlation analysis were applied to analyze the relationship of environmental and atmospheric parameters with AAD occurrence at lags of 0 to 7 days. Specifically, we appraised the air quality index, CO, NO2, SO2, O3, PM10, PM2.5, temperature, dew point temperature, atmospheric pressure, and cloud amount. Results: A total of 1,496 days at risk were assessed, of which 564 patients developed AAD. Specifically, AAD did not occur on 1,043 (69.72%) days, while 1 or more cases occurred on 453 (30.28%) days. Several pollution and weather predictors for AAD were confirmed by multilevel modeling. The air quality index (p = 0.0012), cloud amount (p = 0.0001), and concentrations of PM2.5 (p = 0.0004), PM10 (p = 0.0013), NO2 (p = 0.0007) and O3 (p = 0.0001) predicted AAD as early as 7 days before the incident (lag of 7 days) in the study period. However, only concentrations of the air pollutants NO2 (p = 0.0468) and O3 (p = 0.011) predicted the occurrence of AAD after the COVID-19 outbreak. Similar predictive effects were observed for temperature, dew point temperature, and atmospheric pressure (all p < 0.05) on all days. Conclusion: The risk of AAD is closely related to air pollution and weather characteristics in Harbin. While causation was not determined, the impact of air pollutants on the risk of AAD was reduced after the COVID-19 outbreak.

Rare earth element based single-atom catalysts: synthesis, characterization and applications in photo/electro-catalytic reactions.

Rare earth elements play an important role in various fields, which has attracted increasing interest from the scientific community. Meanwhile, single-atom catalysts show huge advantages in many aspects compared with traditional nanomaterials due to their 100% atomic utilization efficiency. Thus, the combination of the two concepts has yielded an efficient way to realize the high-value utilization of rare earth elements. In this mini-review, rare earth-based single-atom catalysts including their synthesis methods, characterization means and corresponding applications are constructively summarized and discussed. In particular, the important roles of rare earth elements as active centers in photo/electrocatalytic reactions are focused on. Finally, future prospects are also provided.

Quantitative Measures of Crystalline Fenofibrate in Amorphous Solid Dispersion Formulations by X-Ray Microscopy.

In the pharmaceutical industry, amorphous solid dispersion can be utilized to enhance the solubility, hence bioavailability, of poorly solubility active pharmaceutical ingredients owing to the higher free energy of the amorphous state. Measuring the concentration, size and spatial distribution of crystalline API particles that may be present in amorphous solid dispersions (ASD) is critical to understanding product performance and developing improved formulations. In this study X-Ray Microscopy (XRM) was used to nondestructively measure these attributes in ASDs. Model tablets of amorphous fenofibrate in a copovidone matrix spiked with known concentrations of crystalline fenofibrate were examined by XRM to measure the concentration, size and distribution of crystalline particles in the tablets. Data collection and analysis conditions were evaluated and reported. XRM images showed contrast between the crystalline API and the amorphous matrix of the tablet. Image analysis using basic thresholding provided quantitative and distribution data of the crystallinity present. Crystals as small as 10 µm were detected and practical quantitation limits of 0.2% (w/w of total tablet) crystallinity were demonstrated. The aspects of manual data thresholding were tested for operator influence and threshold selection and found to be robust. This technique was demonstrated to provide quantitative measures of crystallinity below standard X-Ray Powder Diffraction (XRPD) techniques, provide three-dimensional information regarding size, shape and distribution of API crystals and can be performed nondestructively.

[Chronic effects of percutaneous transmyocardial laser revascularization in patients with refractory angina].

OBJECTIVE: Conflicting results exist on the therapeutic effects of percutaneous myocardial laser revascularization (PMR) in patients with refractory angina pectoris. This study assessed the effects of PMR on myocardial innervation and perfusion in patients with refractory angina pectoris. METHODS: Patients with refractory angina unsuitable for standard revascularization treatment (PTI and CABG) were randomly divided into medication plus PMR (PMR, n = 17) and medication group (M, n = 13). Coronary sinus noradrenaline (NE) and epinephrine (E) levels, heart rate variability (HRV), total ischemic burden (TIB), and ischemic ST segmental events (STI), myocardial perfusion were evaluated at pre-, immediately post and 12 months post treatment (mean followed up time = 11.6 +/- 4.9 months). RESULTS: In PMR group, one patient developed non-persistent ventricular tachycardia, 2 developed pericardial tamponade and another one patient developed heart failure at 24 h after operation. Coronary sinus NE and E were significantly lower 60 min post PMR compared to pre-PMR and HRV was significantly increased 24 h post PMR. One year post treatments, angina grade was significantly decreased in PMR (1.7 +/- 0.3) than that in M group (0.4 +/- 0.2, P < 0.05) while other parameters were similar between the groups. CONCLUSIONS: PMR induced an early transient denervation and decreased angina grade one year post treatment in patients with refractory angina.

The characterization, selenylation and antidiabetic activity of mycelial polysaccharides from Catathelasma ventricosum.

The mycelial polysaccharide from Catathelasma ventricosum (mCVP-1S) was found to be a heteropolysaccharide with an average size of 230kDa composed mainly of ß-glucopyranosyl residues. The selenylation of mCVP-1S, performed using an HNO3-Na2SeO3 method, produced a series of selenized mCVP-1Ss (SemCVP-1Ss). Varying the reaction time, temperature and Na2SeO3 dosage altered the yield and selenium content of the SemCVP-1Ss. NMR spectra showed substitution mostly at C-6, and Congo red tests indicated excessive selenylation might destroy the triple-helical structure of SemCVP-1Ss. The antidiabetic activities of SemCVP-1Ss with varying selenium contents (low, middle and high) were tested in streptozotocin-induced diabetic mice. In SemCVP-1Ss with triple-helical structure, increasing selenium content enhanced antidiabetic activity, but damage to the triple-helical structure weakened antidiabetic activity. The ability of SemCVP-1Ss to normalize key biochemical parameters in diabetic mice was greater than that of the polysaccharide from the fruiting body of C. ventricosum.

Acoustic one-way metasurfaces: Asymmetric Phase Modulation of Sound by Subwavelength Layer.

We theoretically design and numerically demonstrate an acoustic one-way metasurface, which is a planar and acoustically subwavelength layer behaving like a nearly-reflectionless surface with arbitrary wave-steering capability for incident wave impinging on one side, while virtually blocking the reversed wave. The underlying mechanism is based on an asymmetric phase modulation by coupling a phase array and a near-zero-index medium. We exemplify a metastructure-based implementation by combining the hybrid metastuctures and labyrinthine structures. Moreover, the performance of the proposed implementation is demonstrated via three distinct phenomena of anomalous refraction, wave splitting and conversion of propagation wave to surface wave. Our findings may offer more possibilities for sound manipulation and improve the application potential of acoustic artificial devices in situations such as ultrasonic imaging and therapy.

Three-dimensional broadband acoustic illusion cloak for sound-hard boundaries of curved geometry.

Acoustic illusion cloaks that create illusion effects by changing the scattered wave have many potential applications in a variety of scenarios. However, the experimental realization of generating three-dimensional (3D) acoustic illusions under detection of broadband signals still remains challenging despite the paramount importance for practical applications. Here we report the design and experimental demonstration of a 3D broadband cloak that can effectively manipulate the scattered field to generate the desired illusion effect near curved boundaries. The designed cloak simply comprises positive-index anisotropic materials, with parameters completely independent of either the cloaked object or the boundary. With the ability of manipulating the scattered field in 3D space and flexibility of applying to arbitrary geometries, our method may take a major step toward the real world application of acoustic cloaks and offer the possibilities of building advanced acoustic devices with versatile functionalities.

Mechanical and dynamic characteristics of encapsulated microbubbles coupled by magnetic nanoparticles as multifunctional imaging and drug delivery agents.

Development of magnetic encapsulated microbubble agents that can integrate multiple diagnostic and therapeutic functions is a key focus in both biomedical engineering and nanotechnology and one which will have far-reaching impact on medical diagnosis and therapies. However, properly designing multifunctional agents that can satisfy particular diagnostic/therapeutic requirements has been recognized as rather challenging, because there is a lack of comprehensive understanding of how the integration of magnetic nanoparticles to microbubble encapsulating shells affects their mechanical properties and dynamic performance in ultrasound imaging and drug delivery. Here, a multifunctional imaging contrast and in-situ gene/drug delivery agent was synthesized by coupling super paramagnetic iron oxide nanoparticles (SPIOs) into albumin-shelled microbubbles. Systematical studies were performed to investigate the SPIO-concentration-dependence of microbubble mechanical properties, acoustic scattering response, inertial cavitation activity and ultrasound-facilitated gene transfection effect. These demonstrated that, with the increasing SPIO concentration, the microbubble mean diameter and shell stiffness increased and ultrasound scattering response and inertial cavitation activity could be significantly enhanced. However, an optimized ultrasound-facilitated vascular endothelial growth factor transfection outcome would be achieved by adopting magnetic albumin-shelled microbubbles with an appropriate SPIO concentration of 114.7 µg ml(-1). The current results would provide helpful guidance for future development of multifunctional agents and further optimization of their diagnostic/therapeutic performance in clinic.

Stereological assessment of mouse lung parenchyma via nondestructive, multiscale micro-CT imaging validated by light microscopic histology.

Quantitative assessment of the lung microstructure using standard stereological methods such as volume fractions of tissue, alveolar surface area, or number of alveoli, are essential for understanding the state of normal and diseased lung. These measures are traditionally obtained from histological sections of the lung tissue, a process that ultimately destroys the three-dimensional (3-D) anatomy of the tissue. In comparison, a novel X-ray-based imaging method that allows nondestructive sectioning and imaging of fixed lungs at multiple resolutions can overcome this limitation. Scanning of the whole lung at high resolution and subsequent regional sampling at ultrahigh resolution without physically dissecting the organ allows the application of design-based stereology for assessment of the whole lung structure. Here we validate multiple stereological estimates performed on micro-computed tomography (µCT) images by comparing them with those obtained via conventional histology on the same mouse lungs. We explore and discuss the potentials and limitations of the two approaches. Histological examination offers higher resolution and the qualitative differentiation of tissues by staining, but ultimately loses 3-D tissue relationships, whereas µCT allows for the integration of morphometric data with the spatial complexity of lung structure. However, µCT has limited resolution satisfactory for the sterological estimates presented in this study but not for differentiation of tissues. We conclude that introducing stereological methods in µCT studies adds value by providing quantitative information on internal structures while not curtailing more complex approaches to the study of lung architecture in the context of physiological or pathological studies.

X-ray computed tomography of holographically fabricated three-dimensional photonic crystals.

X-ray computed tomography is used to reconstruct the 3D structure of a polymeric photonic crystal. The reconstructed structure is compared to the structure predicted by a model. This analysis provides means to better understand deformations that occur during holographic fabrication of photonic crystals.

Apatite microtopographies instruct signaling tapestries for progenitor-driven new attachment of teeth.

Dimension and structure of extracellular matrix surfaces have powerful influences on cell shape, adhesion, and gene expression. Here we show that natural tooth root topographies induce integrin-mediated extracellular matrix signaling cascades in tandem with cell elongation and polarization to generate physiological periodontium-like tissues. In this study we replanted surface topography instructed periodontal progenitors into rat alveolar bone sockets for 8 and 16 weeks, resulting in complete reattachment of tooth roots to the surrounding alveolar bone with a periodontal fiber apparatus closely matching physiological controls along the entire root surface. Displacement studies and biochemical analyses confirmed that progenitor-based engineered periodontal tissues were similar to control teeth and uniquely derived from preimplantation green fluorescent protein (GFP)-labeled progenitors. Together, these studies illustrate the capacity of natural extracellular surface topographies to instruct progenitor cell populations to fully regenerate complex cellular and structural morphologies of tissues once lost to disease. We suggest that our strategy could be used for the replantation of teeth lost due to trauma or as a novel approach for tooth replacement using tooth-shaped replicas.

Focusing ultrasound with an acoustic metamaterial network.

We present the first experimental demonstration of focusing ultrasound waves through a flat acoustic metamaterial lens composed of a planar network of subwavelength Helmholtz resonators. We observed a tight focus of half-wavelength in width at 60.5 kHz by imaging a point source. This result is in excellent agreement with the numerical simulation by transmission line model in which we derived the effective mass density and compressibility. This metamaterial lens also displays variable focal length at different frequencies. Our experiment shows the promise of designing compact and lightweight ultrasound imaging elements.

Subwavelength focusing and guiding of surface plasmons.

The constructive interference of surface plasmon polaritons (SPP) launched by nanometric holes allows us to focus SPP into a spot of high near-field intensity having subwavelength width. Near-field scanning optical microscopy is used to map the local SPP intensity. The resulting SPP patterns and their polarization dependence are accurately described in model calculations based on a dipolar model for the SPP emission at each hole. Furthermore, we show that the high SPP intensity in the focal spot can be launched and propagated on a Ag strip guide with a 250 x 50 nm2 cross section, thus overcoming the diffraction limit of conventional optics. The combination of focusing arrays and nano-waveguides may serve as a basic element in planar nano-photonic circuits.