差示扫描量热法测定比沙可啶的纯度

建立差示扫描量热法测定比沙可啶原料药样品纯度的方法。考察了炉体气氛、升温速率、称样量3个因素对差示扫描量热法测定结果的影响,确定差示扫描量热法最佳实验条件:升温速率为2.0 K/min,称样量为2.0~4.0 mg,炉内气体为静态空气。差示扫描量热法测定比沙可啶样品纯度为99.86%,测定结果的相对标准偏差为0.02%(n=6),差示扫描量热法测定比沙可啶样品纯度值与HPLC测定结果具有良好的一致性。该方法可以快速、准确地测定比沙可啶化学纯度,为比沙可啶纯度测定提供了一种新的分析方法。     

Theoretical studies of the concentration dependences of d–d transition band,g factors,and local distortion for V4+ in Li2O–PbO–B2O3–P2O5 glasses

In this work, the g factors, d–d transition band, local distortion, and their concentration dependences for impurity V⁴⁺ in 20Li₂O–20PbO–45B₂O₃–(15 − x)P₂O₅:V₂O₅ (0 ≤ x ≤ 2.5 mol%) glasses are theoretically investigated by using perturbation formulas of g factors for a tetragonally compressed octahedral 3d¹ cluster. In the light of the cubic polynomial concentration functions for cubic field parameter D_q, covalency factor N, and relative tetragonal compression ratio ρ, the calculated concentration dependences of d–d transition band and g factors for V⁴⁺ show good agreement with the experimental data. With increasing x, N (≈0.7682–0.8165) displays the monotonously increasing trend, whereas ρ (≈6.5–4.2%) and D_q (≈1504.9–1481.1 cm⁻¹) exhibit the decreasing tendencies. The above concentration dependences can be ascribed to the modifications of the V⁴⁺–O²⁻ bonding and orbital admixtures around the impurity V⁴⁺ due to the effects of V₂O₅ doping on the stability of the glass network, the strength of local crystal fields, and the electron cloud distribution.     

非离子型表面活性剂Tween 60用于碳纳米管的双水相分离

单壁碳纳米管以其优异的电学和光学性能受到了广泛的关注,高性能器件等应用要求使用性质均一的单壁碳纳米管.因此,不同结构的单壁碳纳米管的分离具有重要意义.双水相萃取是一种能够对单壁碳纳米管进行结构分离的新方法,分离结果稳定可靠,且不需要复杂的设备,具有简捷、高效、易扩大规模等特点.本文通过调节脱氧胆酸钠(DOC)和非离子型...     

Facile Surfactant-, Reductant-, and Ag Salt-free Growth of Ag Nanoparticles with Controllable Size from 35 to 660 nm on Bulk Ag Materials

Morphologically and dimensionally controlled growth of Ag nanocrystals has long been plagued by surfactants or capping agents that complicate downstream applications, unstable Ag salts that impaired the reproducibility, and multistep seed injection that is troublesome and time-consuming. Here, we report a one-pot electro-chemical method to fast (∼2 min) produce Ag nanoparticles from commercial bulk Ag materials in a nitric acid solution, eliminating any need for surfactants or capping agents. Their size can be easily manipulated in an unprecedentedly wide range from 35 to 660 nm. Furthermore, the Ag nanoparticles are directly grown on the Ag substrate, highly desirable for promising applications such as catalysis and plasmonics. The mechanistic studies reveal that the concentration of Ag⁺ in the diffusion layer nearby the surface, controlled by the magnitude and duration of voltage, is critical in governing the nanoparticle formation (<1.3 mM) and its dimensional adjustability.     

Strain‐Induced Isomerization in One‐Dimensional Metal–Organic Chains

The ability to use mechanical strain to steer chemical reactions creates completely new opportunities for solution‐ and solid‐phase synthesis of functional molecules and materials. However, this strategy is not readily applied in the bottom‐up on‐surface synthesis of well‐defined nanostructures. We report an internal strain‐induced skeletal rearrangement of one‐dimensional (1D) metal–organic chains (MOCs) via a concurrent atom shift and bond cleavage on Cu(111) at room temperature. The process involves Cu‐catalyzed debromination of organic monomers to generate 1,5‐dimethylnaphthalene diradicals that coordinate to Cu adatoms, forming MOCs with both homochiral and heterochiral naphthalene backbone arrangements. Bond‐resolved non‐contact atomic force microscopy imaging combined with density functional theory calculations showed that the relief of substrate‐induced internal strain drives the skeletal rearrangement of MOCs via 1,3‐H shifts and shift of Cu adatoms that enable migration of the monomer backbone toward an energetically favorable registry with the Cu(111) substrate. Our findings on this strain‐induced structural rearrangement in 1D systems will enrich the toolbox for on‐surface synthesis of novel functional materials and quantum nanostructures.     

A Photolabile Semiconducting Polymer Nanotransducer for Near‐Infrared Regulation of CRISPR/Cas9 Gene Editing

Noninvasive regulation of CRISPR/Cas9 gene editing is conducive to understanding of gene function and development of gene therapy; however, it remains challenging. Herein, a photolabile semiconducting polymer nanotransducer (pSPN) is synthesized to act as the gene vector to deliver CRISPR/Cas9 plasmids into cells and also as the photoregulator to remotely activate gene editing. pSPN comprises a ¹O₂‐generating backbone grafted with polyethylenimine brushes through ¹O₂‐cleavable linkers. NIR photoirradiation spontaneously triggers the cleavage of gene vectors from pSPN, resulting in the release of CRISPR/Cas9 plasmids and subsequently initiating gene editing. This system affords 15‐ and 1.8‐fold enhancement in repaired gene expression relative to the nonirradiated controls in living cells and mice, respectively. As this approach does not require any specific modifications on biomolecular components, pSPN represents the first generic nanotransducer for in vivo regulation of CRISPR/Cas9 gene editing.     

Reactivity of the Hydroxy Groups in Melezitose and Their Selective Protection

The reactivity of melezitose hydroxy groups was studied by tritylation in pyridine with subsequent acetylation. After partial detritylation of the products, acetyl group transfer from position 4 to 6 was observed. The structure of the prepared melezitose derivatives was established on the basis of their IR, ¹H, ¹³C, and ¹H-¹H COSY NMR, and mass spectra (fast atom bombardment), as well as from the results of model calculations performed with the aid of SGI Indigo Molecule-Pattern-Work-Station software package (Biosym) where the potential energy function was approximated with the CVFF potential. The reactivity of primary hydroxy groups in melezitose was found to decrease in the following order: 6' > 6 6' > 1'.     

A Renal‐Clearable Duplex Optical Reporter for Real‐Time Imaging of Contrast‐Induced Acute Kidney Injury

Despite its high morbidity and mortality, contrast‐induced acute kidney injury (CIAKI) remains a diagnostic dilemma because it relies on in vitro detection of insensitive late‐stage blood and urinary biomarkers. We report the synthesis of an activatable duplex reporter (ADR) for real‐time in vivo imaging of CIAKI. ADR is equipped with chemiluminescence and near‐infrared fluorescence (NIRF) signaling channels that can be activated by oxidative stress (superoxide anion, O₂^.?) and lysosomal damage (N‐acetyl‐β‐d ‐glucosaminidase, NAG), respectively. By virtue of its high renal clearance efficiency (80 % injected doses after 24 h injection), ADR detects sequential upregulation of O₂^.? and NAG in the kidneys of living mice prior to a significant decrease in glomerular filtration rate (GFR) and tissue damage in the course of CIAKI. ADR outperforms the typical clinical assays and detects CIAKI at least 8 h (NIRF) and up to 16 h (chemiluminescence) earlier.     

5 nm Ordered Structures Self-Assembled by C2-Symmetric Hybrids with Polyhedral Oligomeric Silsesquioxane and Hexa-peri-Hexabenzocoronene.

Hybrids consisting of polyhedral oligomeric silsesquioxane (POSS) and hexa-peri-hexabenzocoronene (HBC) with a dumbbell topology and C₂ symmetry were designed and synthesized. They self-assemble into 5 nm ordered structures. In particular, the increased steric effect with increasing POSS units stabilizes a square columnar phase (Col_squ) which is important in nanotemplating. These hybrids containing discotic liquid crystal HBC and POSS units have an excellent etching contrast and present an approach to obtain 5 nm nanopatterns.     

Supramolecular Sensor for Astringent Procyanidin C1: Fluorescent Artificial Tongue for Wine Components

An artificial tongue that detects astringent components for a comprehensive evaluation of taste has not been established to date. Herein, we first propose fluorescent polythiophene (PT) derivatives ( S1 – S3 ) modified with 3-pyridinium boronic acid as supramolecular chemosensors for wine components including astringent procyanidin C1. After numerous attempts for the synthetic conditions, more than 95 mol % of the PT unit was modified with the pyridinium boronic acid moiety. To evaluate the PT derivatives as chemosensors of the artificial tongue, qualitative and quantitative analyses were performed with four types of wine components (i.e., sweet, sour, bitter, and astringent tastes) in combination with pattern recognition models. Notably, procyanidin C1 in the actual wine sample was successfully detected in a quantitative manner. In other words, we have established an authentic artificial tongue using PT based supramolecular chemosensors.