Ultrasensitive Detection of DNA and Ramos Cell Using In Situ Selective Crystallization Based Quartz Crystal Microbalance

Herein we introduce the first successful assay of biomolecule by in situ selective crystallization based quartz crystal microbalance (QCM). Selective crystallization of CaCO₃ on QCM sensor surface was utilized as an efficient mass amplification strategy and enhanced the sensitivity of QCM significantly. High specificity is guaranteed by the cooperation of two functional groups: −N­(CH₃)₃ and −COOH. Passivation of sensor surface is realized by self-assembly of −N­(CH₃)₃, which effectively inhibited the nonspecific crystallization. The DNA target is detected through hybridization of probe DNA labeled with −COOH, which can effectively promot the in situ surface crystallization of CaCO₃. The concentration of target DNA is reflected by the frequency shift of QCM which is directly induced by the surface crystallization. The selective crystallization based QCM platform is simple, straightforward, high sensitive, and high specific. We demonstrate the excellent LOD (2 aM DNA) and a linear range of 10aM to 1 nM for DNA. Detection of Ramos cells are also realized with a LOD of five cells and a linear range of 5–6000 cells

Quasi-Two-Dimensional Halide Perovskite Single Crystal Photodetector

The robust material stability of the quasi-two-dimensional (quasi-2D) metal halide perovskites has opened the possibility for their usage instead of three-dimensional (3D) perovskites. Further, devices based on large area single crystal membranes have shown increasing promise for photoelectronic applications. However, growing inch-scale quasi-2D perovskite single crystal membranes (quasi-2D PSCMs) has been fundamentally challenging. Here we report a fast synthetic method for synthesizing inch-scale quasi-2D PSCMs, namely (C₄H₉NH₃)_<i>n</i>(CH₃NH₃)_<i>n</i>−1Pb_<i>n</i>I_3<i>n</i>+1 (index <i>n</i> = 1, 2, 3, 4, and ∞), and demonstrate their application in a single-crystal photodetector. A quasi-2D PSCM has been grown at the water–air interface where spontaneous alignment of alkylammonium cations and high chemical potentials enable uniform orientation and fast in-plane growth. Structural, optical, and electrical characterizations have been conducted as a function of quantum well thickness, which is determined by the index <i>n</i>. It is shown that the photodetector based on the quasi-2D PSCM with the smallest quantum well thickness (<i>n</i> = 1) exhibits a strikingly low dark current of ∼10^–13 A, higher on/off ratio of ∼10⁴, and faster response time in comparison to those of photodetectors based on quasi-2D PSCMs with larger quantum well thickness (<i>n</i> > 1). Our study paves the way toward the merging the gap between single crystal devices and the emerging quasi-2D perovskite materials

Quasi-Two-Dimensional Halide Perovskite Single Crystal Photodetector

The robust material stability of the quasi-two-dimensional (quasi-2D) metal halide perovskites has opened the possibility for their usage instead of three-dimensional (3D) perovskites. Further, devices based on large area single crystal membranes have shown increasing promise for photoelectronic applications. However, growing inch-scale quasi-2D perovskite single crystal membranes (quasi-2D PSCMs) has been fundamentally challenging. Here we report a fast synthetic method for synthesizing inch-scale quasi-2D PSCMs, namely (C₄H₉NH₃)_<i>n</i>(CH₃NH₃)_<i>n</i>−1Pb_<i>n</i>I_3<i>n</i>+1 (index <i>n</i> = 1, 2, 3, 4, and ∞), and demonstrate their application in a single-crystal photodetector. A quasi-2D PSCM has been grown at the water–air interface where spontaneous alignment of alkylammonium cations and high chemical potentials enable uniform orientation and fast in-plane growth. Structural, optical, and electrical characterizations have been conducted as a function of quantum well thickness, which is determined by the index <i>n</i>. It is shown that the photodetector based on the quasi-2D PSCM with the smallest quantum well thickness (<i>n</i> = 1) exhibits a strikingly low dark current of ∼10^–13 A, higher on/off ratio of ∼10⁴, and faster response time in comparison to those of photodetectors based on quasi-2D PSCMs with larger quantum well thickness (<i>n</i> > 1). Our study paves the way toward the merging the gap between single crystal devices and the emerging quasi-2D perovskite materials

Data_Sheet_1_Osteoporosis is associated with elevated baseline cerebrospinal fluid biomarkers and accelerated brain structural atrophy among older people.docx

ObjectiveThe aim of this study was to examine whether osteoporosis (OP) is associated with Alzheimer’s disease-related cerebrospinal fluid (CSF) biomarkers and brain structures among older people.MethodsFrom the Alzheimer’s disease Neuroimaging Initiative database, we grouped participants according to the OP status (OP+/OP−) and compared the Alzheimer’s disease (AD)-related CSF biomarker levels and the regional brain structural volumes between the two groups using multivariable models. These models were adjusted for covariates including age, education, gender, diagnosis of Alzheimer’s disease, and apolipoprotein E4 carrier status.ResultsIn the cross-sectional analyses at baseline, OP was related to higher CSF t-tau (total tau) and p-tau181 (tau phosphorylated at threonine-181) but not to CSF amyloid-beta (1–42) or the volumes of entorhinal cortex and hippocampus. In the longitudinal analyses, OP was not associated with the change in the three CSF biomarkers over time but was linked to a faster decline in the size of the entorhinal cortex and hippocampus.ConclusionOP was associated with elevated levels of CSF t-tau and p-tau181 at baseline, and accelerated entorhinal cortex and hippocampal atrophies over time among older people.</p

Improved Phase Stability of Formamidinium Lead Triiodide Perovskite by Strain Relaxation

Though formamidinium lead triiodide (FAPbI₃) possesses a suitable band gap and good thermal stability, the phase transition from the pure black perovskite phase (α-phase) to the undesirable yellow nonperovskite polymorph (δ-phase) at room temperature, especially under humid air, hinders its practical application. Here, we investigate the intrinsic instability mechanism of the α-phase at ambient temperature and demonstrate the existence of an anisotropic strained lattice in the (111) plane that drives phase transformation into the δ-phase. Methylammonium bromide (MABr) alloying (or FAPbI₃-MABr) was found to cause lattice contraction, thereby balancing the lattice strain. This led to dramatic improvement in the stability of α-FAPbI₃. Solar cells fabricated using FAPbI₃-MABr demonstrated significantly enhanced stability under the humid air

The Controlling Mechanism for Potential Loss in CH₃NH₃PbBr₃ Hybrid Solar Cells

We investigated moisture and thermal stability of MAPbBr₃ perovskite material. Cubic MAPbBr₃ was found to be moisture-insensitive and can avoid the thermal stability issues introduced by low-temperature phase transition in MAPbI₃. MAPbBr₃ and MAPbI₃ hybrid solar cells with efficiencies of ∼7.1% and ∼15.5%, respectively, were fabricated, and we identified the correlation between the working temperature, light intensity, and the photovoltaic performance. No charge-carrier transport barriers were found in the MAPbBr₃ and MAPbI₃ solar cells. The MAPbBr₃ solar cell displays a better stability under high working temperature because of its close-packed crystal structure. Temperature-dependent photocurrent–voltage characteristics indicate that, unlike the MAPbI₃ solar cell with an activation energy (<i>E</i>_A) nearly equal to its band gap (<i>E</i>_g), the <i>E</i>_A for the MAPbBr₃ solar cell is much lower than its <i>E</i>_g. This indicates that a high interface recombination process limits the photovoltage and consequently the device performance of the MAPbBr₃ solar cell

Efficient Charge Transfers in Highly Conductive Copper Selenide Quantum Dot-Confined Catalysts for Robust Oxygen Evolution Reaction

Defective quantum dots (QDs) are the emerging materials for catalysis by virtue of their atomic-scale size, high monodispersity, and ultra-high specific surface area. However, the dispersed nature of QDs fundamentally prohibits the efficient charge transfer in various catalytic processes. Here, we report efficient and robust electrocatalytic oxygen evolution based on defective and highly conductive copper selenide (CuSe) QDs confined in an amorphous carbon matrix with good uniformity (average diameter 4.25 nm) and a high areal density (1.8 × 1012 cm–2). The CuSe QD-confined catalysts with abundant selenide vacancies were prepared by using a pulsed laser deposition system benefitted by high substrate temperature and ultrahigh vacuum growth conditions, as evidenced by electron paramagnetic resonance characterizations. An ultra-low charge transfer resistance (about 7 Ω) determined by electrochemical impedance spectroscopy measurement indicates the efficient charge transfer of CuSe quantum-confined catalysts, which is guaranteed by its high conductivity (with a low resistivity of 2.33 μΩ·m), as revealed by electrical transport measurements. Our work provides a universal design scheme of the dispersed QD-based composite catalysts and demonstrates the CuSe QD-confined catalysts as an efficient and robust electrocatalyst for oxygen evolution reaction

DataSheet1_Genome-wide identification, evolution and expression analysis of bone morphogenetic protein (BMP) gene family in chinese soft-shell turtle (Pelodiscus sinensis).ZIP

Introduction: Bone morphogenetic proteins (BMPs) play a crucial role in bone formation and differentiation. Recent RNA-Seq results suggest that BMPs may be involved in the sex differentiation of P. sinensis, yet more relevant studies about BMPs in P. sinensis are lacking.Methods: Herein, we identified BMP gene family members, analyzed the phylogeny, collinear relationship, scaffold localization, gene structures, protein structures, transcription factors and dimorphic expression by using bioinformatic methods based on genomic and transcriptomic data of P. sinensis. Meanwhile, qRT-PCR was used to verify the RNA-Seq results and initially explore the function of the BMPs in the sex differentiation of P. sinensis.Results: A total of 11 BMP genes were identified, 10 of which were localized to their respective genomic scaffolds. Phylogenetic analysis revealed that BMP genes were divided into eight subfamilies and shared similar motifs (“WII”, “FPL”, “TNHA”, “CCVP”, and “CGC”) and domain (TGF-β superfamily). The results of the sexually dimorphic expression profile and qRT-PCR showed that Bmp2, Bmp3, Bmp15l, Bmp5, Bmp6 and Bmp8a were significantly upregulated in ovaries, while Bmp2lb, Bmp7, Bmp2bl and Bmp10 were remarkable upregulated in testes, suggesting that these genes may play a role in sex differentiation of P. sinensis.Discussion: Collectively, our comprehensive results enrich the basic date for studying the evolution and functions of BMP genes in P. sinensis.</p