Preparation and characterization of an aptamer‐functionalized solid‐phase microextraction fiber and its application in the selective monitoring of adenosine phosphates with liquid chromatography and tandem mass spectrometry

An aptamer with adenosine triphosphate as a ligand was immobilized onto the surface of a porous‐polymer‐coated fiber to obtain an aptamer‐functionalized porous‐polymer‐coated solid‐phase microextraction fiber. The fiber was observed with a crosslinked and porous morphological surface structure. It shows specific selectivity to adenosine triphosphate with a selectivity coefficient of 22.1 compared to the scrambled oligonucleotide functionalized fiber, and the selectivity factors over other analogues and reference compounds were from 6.1 to 77.5. When the fiber‐based solid‐phase microextraction was coupled with liquid chromatography and tandem mass spectrometry, detection limits of 2.7, 29, and 34 μg/L were achieved for adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate, respectively. The spiking recoveries of 77.6–91.9% were achieved for trace adenosine phosphates in human serum sample. Furthermore, the fibers showed high stability and good reusability and could be used over 50 times for the real serum sample pretreatment without remarkable performance reduction.     

Screening and quantification of anticancer compounds in traditional Chinese medicine by hollow fiber cell fishing and hollow fiber liquid/solid‐phase microextraction

Hollow fiber cell fishing, based on HepG‐2, SKOV‐3, and ACHN cancer cells, and hollow fiber liquid/solid microextraction with HPLC were developed and introduced for researching the anticancer activity of Rhizoma Curcumae Longae, Radix Curcumae, and Rhizoma Curcumae. The structures of curcumin, demethoxycurcumin, and bisdemethoxycurcumin screened were identified and their contents were determined. The compound target fishing factors and cell apoptosis rates under the effect of the three medicines were determined. The binding sites (cell membrane and cell organelle) and binding target (phospholipase C) on the cell were researched. Hollow fiber liquid/solid‐phase microextraction mechanism was analyzed and expounded. Before the application, cell seeding time, growth state and survival rate, compound nonspecific binding, positive and negative controls, repeatability in hollow fiber cell fishing with high‐performance liquid chromatography; extraction solvent, sample pH, salt concentration, agitation speed, extraction time, temperature and sample volume in hollow fiber liquid/solid‐phase microextraction with high‐performance liquid chromatography were investigated. The results demonstrated that the proposed strategy is a simple and quick method to identify bioactive compounds at the cellular level as well as determine their contents (particularly trace levels of the bioactive compounds), analyze multicompound and multitarget entirety effects, and elucidate the efficacious material base in traditional medicine.     

Self‐assembly of a Linear Ni9 Triple‐helical Supramolecule with Dominant Ferromagnetic Interactions

A linear triple‐helical supramolecule Ni₉ L ₆ has been prepared through a controllable self‐assembly approach using 1,3‐bis‐(3‐oxo‐3‐phenylpropionyl)‐2‐hydroxy‐5‐methylbenzene (H₃ L ) and Ni(OAc)₂ under solvothermal conditions. Single‐crystal X‐ray diffraction analysis confirms the axial C₃ symmetrical helical structure of the product and the temperature‐dependent magnetic susceptibility corresponds to a typical shape of a paramagnet showing dominant ferromagnetic exchange couplings between the neighboring Ni^II ions.     

Redox-responsive core cross-linked micelles of poly(ethylene oxide)-b-poly(glycidyl methacrylate) by click chemistry

ABSTRACT

Redox-responsive core cross-linked polymeric micelles were prepared by using azide-alkyne click chemistry. Poly(ethylene oxide)-b-poly(glycidyl methacrylate) (PEO-b-PGMA) copolymers were prepared by the atom transfer radical polymerization, and the PGMA parts were subsequently functionalized with azido groups. The micelles of azido-functional PEO_5k-b-PGMA_1.1k-N₃ were cross-linked using dipropargyl 3,3′-dithiodipropionate as a disulfide-containing cross-linking agent. The block copolymers and polymeric micelles were characterized by using GPC, FT-IR, ¹H NMR, TEM, and DLS analyses. The nanoparticle micelles showed much improved structural stability under physiological condition, while they were rapidly dissociated in the 1,4-dithio-D,L-threitol reducing environment.     

Dependence of Hilbert coefficients

Let M be a finitely generated module of dimension d and depth t over a Noetherian local ring (A, \({\mathfrak{m}}\)) and I an \({\mathfrak{m}}\)-primary ideal. In the main result it is shown that the last t Hilbert coefficients \({e_{d-t+1}(I,M),\ldots, e_{d}(I,M)}\) are bounded below and above in terms of the first d ? t + 1 Hilbert coefficients \({e_{0}(I,M),\ldots,e_{d-t}(I,M)}\) and d.     

A new rhodamine-based fluorescent chemosensor for transition metal cations synthesized by one-step facile condensation

A new rhodamine-based fluorescent chemosensor (1) for transition metal cations was synthesized by one-step facile condensation of rhodamine B and 2-aminopyridine. Without metal cations, 1 is colorless and nonfluorescent, whereas addition of metal cations (Fe³⁺, Hg²⁺, Pb²⁺, and Fe²⁺) leads to an obvious color change to pink and an appearance of orange fluorescence.     

Structure elucidation and complete NMR spectral assignments of three new lanostanoid triterpenes with unprecedented Delta(16, 17) double bond from Ganoderma lucidum

Three new lanostanoid triterpenes named 3beta,7beta-di- hydroxy-11,15,23-trioxo-lanost-8,16-dien-26-oic acid (1), 3beta,7beta-dihydroxy-11,15,23-trioxo-lanost-8,16-dien-26-oic acid methyl ester (2), and 12beta-acetoxy-3beta,7beta-dihydroxy-11,15,23-trioxo-lanost-8,16-dien-26-oic acid (3) were isolated from the fruit bodies of Ganoderma lucidum. They all show a Delta(16, 17) double bond unprecedented in such types of lanostanoid triterpenes possessing the side chain at C-17. The complete NMR assignments for these compounds were carried out using (1)H, (13)C, DEPT, COSY, HSQC, HMBC, and ROESY NMR experiments.     

Fabrication of spindle Fe(2)O(3)@polypyrrole core/shell particles by surface-modified hematite templating and conversion to spindle polypyrrole capsules and carbon capsules

By using a surface-modified templating method, Fe(2)O(3)@polypyrrole (PPy) core/shell spindles have been successfully prepared in this paper. The Fe(2)O(3) particles with spindle morphology were initially fabricated as core materials. After the PVP modification, the Fe(2)O(3) spindles were subsequently coated with a tunable thickness layer of PPy by in situ deposition of the conducting polymer from aqueous solution. Hollow PPy spindles were produced by dissolution of the Fe(2)O(3) core from the core/shell particles. High-temperature treatment under vacuum condition covert the hollow PPy spindles into carbon capsules by carbonization of the PPy shell. Transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) confirmed the formation of the Fe(2)O(3)@PPy core/shell particles, PPy and carbon capsules with spindle morphology.     

Smart Titanium Coating Composed of Antibiotic Conjugated Peptides as an Infection‐Responsive Antibacterial Agent

Antibacterial coating is rapidly emerging as a pivotal strategy for mitigating spread of bacterial pathogens. However, many challenges still need to be overcome in order to develop a smart coating that can achieve on‐demand antibacterial effects. In this study, a Staphylococcus aureus (S. aureus) sensitive peptide sequence is designed, and an antibiotic is then conjugated with this tailor‐made peptide. The antibiotic‐peptide conjugate is then linked to the surface of a titanium implant, where the peptide can be recognized and cleaved by an enzyme secreted by S. aureus. This allows for the release of antibiotics in the presence of S. aureus, thus achieving delivery of an antibacterial specifically when an infection occurs.     

超声参数联合血清OPN、IL-1β对乳腺癌的临床诊断价值研究

选取我院收治的乳腺癌(BC)患者82例设为研究组,同期乳腺良性肿瘤患者82例设为对照组,探讨了超声参数联合血清骨桥蛋白(OPN)、白细胞介素-1β(IL-1β)对BC的诊断价值。结果显示,研究组患者病灶处的RI值、PI值和血清OPN、IL-1β水平均高于对照组(P<0.05);PI值、RI值、血清OPN、IL-1β水平与临床分期、肿瘤直径、远处转移存在正相关关系(P<0.05);预后良好者PI、RI、OPN、IL-1β低于预后不良者(P<0.05);超声参数联合血清OPN、IL-1β诊断BC的AUC值为0.900,预测预后的AUC值为0.875。本研究证实BC患者存在超声参数及血清OPN、IL-1β水平异常情况,且异常程度与疾病病理特征关系密切,通过超声参数及相关血清因子水平可对乳腺病变情况进行鉴别,并指导临床制定治疗方案。