早产儿喂养不耐受

早产儿喂养不耐受可导致早期营养不良、生长受限,对以后的行为和认知产生影响,是目前新生儿科医生面临的重要问题。喂养不耐受与早产儿胃肠功能不成熟、围生期窒息、感染等疾病因素相关。临床治疗常采用微量喂养,促胃肠动力药、口服益生菌等方法,但目前尚无统一的预防和治疗指南。     

端粒酶与女性生殖功能

端粒酶是细胞中负责端粒延长的一种酶,通过合成染色体末端的DNA赋予细胞复制的永生性。其在保持端粒稳定、基因组完整、细胞长期的活性和潜在的继续增殖能力等方面有重要作用,端粒/端粒酶复合物的结构和功能的改变将会导致不同的疾病,尤其是癌症的发生。在人类正常生殖细胞、早期胚胎、干细胞、高度增殖体细胞和许多癌细胞中均有不同程度的端粒酶活性表达,并受到严密的调控。在女性生殖功能调控下,端粒酶活性表达在卵泡的发育及闭锁、子宫内膜的周期性变化、卵巢储备功能及性激素调节等方面发挥着重要的作用,并可在一定程度上预测卵巢储备功能及体外受精妊娠结局。     

气道正压通气治疗高血压伴阻塞性睡眠呼吸暂停低通气综合征

目的经鼻持续气道正压通气(nCPAP)治疗高血压合并阻塞性睡眠呼吸暂停低通气综合征(OS-AHS)患者,以评价该疗法对血压和睡眠呼吸监测参数的影响。方法临床确诊合并OSAHS的高血压患者,随机分为治疗组和对照组,治疗组在给予常规药物(抗高血压药、抗动脉硬化药物)治疗的同时进行nCPAP治疗,对照组仅给予常规药物治疗。30天后,观察两组治疗前后血压、睡眠呼吸监测参数变化。结果高血压合并OSAHS患者共60例,治疗组和对照组各30例;治疗后治疗组的收缩压(SBP)、舒张压(DBP)、脉压(PP)、心率(HR)、睡眠呼吸暂停低通气指数(AHI)、最长呼吸暂停时间和最低脉搏容积血氧饱和度(SpO2min),与对照组比较差异有统计学意义(P<0.05);部分患者降压药物减量或停用,仅用nCPAP治疗就能维持正常血压。结论nCPAP是非药物治疗合并OSAHS高血压患者的一种安全有效方法。     

Knockdown of augmenter of liver regeneration in HK-2 cells inhibits inflammation response via the mitogen-activated protein kinase signaling pathway

Inflammation Research - Augmenter of liver regeneration (ALR) is a growth factor that is ubiquitously expressed in multiple forms among eukaryotes. The present study focused on the role of...     

Synthesis,characterization and olefin polymerization behaviors of phenylene-bridged bis-β-carbonylenamine binuclear titanium complexes

Binuclear and multinuclear complexes have attracted much attention due to their unique catalytic performances for olefin polymerization compared with their mononuclear counterparts. In this work, a series of phenyl-bridged bis-β-carbonylenamine [O⁻NS^R] (R = alkyl or phenyl) tridentate ligands and their binuclear titanium complexes (Ti²L₁–Ti²L₅) were synthesized and characterized by ¹H NMR, ¹³C NMR, FTIR and elemental analysis. The molecular structure of ligand L₂ (R = ⁿPr) and its corresponding Ti complex Ti²L₂ were further investigated by single-crystal X-ray diffraction, which showed that each titanium coordinated with six atoms to form a distorted octahedral configuration along with the conversion of the ligand from β-carbonylenamine to β-imino enol form. Under the activation of MMAO, these complexes catalyzed ethylene polymerization and ethylene/α-olefin copolymerization with extremely high activity (over 10⁶ g mol (Ti)⁻¹ h⁻¹ atm⁻¹) to produce high molecular weight polyethylene. At the same time, wider polydispersity as compared with the mononuclear counterpart TiL₆ was observed, indicating that two active catalytic centers may be present, consistent with the asymmetrical crystal structure of the binuclear titanium complex. Furthermore, these complexes possessed better thermal stability than their mononuclear analogues. Compared with the complexes bearing alkylthio sidearms, the complex Ti²L₅ bearing a phenylthio sidearm exhibited higher catalytic activity towards ethylene polymerization and produced polyethylene with much higher molecular weight, but with an appreciably lower 1-hexene incorporation ratio. Nevertheless, these bis-β-carbonylenamine-derived binuclear titanium complexes showed much higher ethylene/1-hexene copolymerization activity and 1-hexene incorporation ratios as compared with the methylene-bridged bis-salicylaldiminato binuclear titanium complexes, and the molecular weight and 1-hexene incorporation ratio could be flexibly tuned by the initial feed of α-olefin commoners and catalyst structures.

Phenyl-bridged bis-β-carbonylenamine binuclear titanium complexes were synthesized, characterized and used to catalyze ethylene (co)polymerization with extremely high activity.     

Fabrication and photocatalytic property of magnetic SrTiO3/NiFe2O4 heterojunction nanocomposites

Novel multifunctional SrTiO₃/NiFe₂O₄ nanocomposites were successfully fabricated via a two-step route. The as-prepared samples were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), field-emission transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). The results indicate that the SrTiO₃/NiFe₂O₄ heterostructures are composed of SrTiO₃ spheroidal nanoparticles adhered to NiFe₂O₄ polyhedra. The heterojunction established in the composite material accelerates the process of electron–hole pair separation and boosts the photo-Fenton reaction. Among the samples, 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites exhibit a powerful light response and excellent room temperature ferromagnetism. Subsequently, the photocatalytic degradation of RhB over the as-prepared samples was investigated and optimized, revealing that the 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites exhibit the best photocatalytic activity and stability under simulated solar light irradiation. Furthermore, according to experimental results, the possible mechanism of improved photocatalytic activity was also proposed.

Photocatalytic degradation of RhB for all samples under simulated solar light illumination and absorption spectra of RhB over 15 wt% SrTiO₃/NiFe₂O₄ nanocomposites.     

Synergetic effects of bimetals in modified beta zeolite for lactic acid synthesis from biomass-derived carbohydrates

An experimental study was carried out to convert carbohydrates using bimetal modified beta zeolite to obtain a maximum yield of lactic acid. The relationship between the properties and the catalytic performance of various bimetal modified beta zeolites was evaluated. The results showed that the maximum yield of lactic acid reached 52% with more than 99% glucose conversion over Pb–Sn-beta (0.3 mmol g⁻¹, Pb/Sn = 4 : 7) at 190 °C for 2 h under ambient air pressure. To evaluate the synergetic mechanism of lead and tin, key intermediates such as fructose, dihydroxyacetone, glyceraldehyde and pyruvaldehyde were used as probe reactants that were catalyzed by Pb-beta, Sn-beta and Pb–Sn-beta. The revealed key role of lead was to promote the isomerization of glucose to fructose and the retro-aldol condensation reaction from fructose to dihydroxyacetone and glyceraldehyde; meanwhile, tin had a superior catalytic performance in the dehydration of dihydroxyacetone, the hydration of pyruvaldehyde and the isomerization of pyruvic aldehyde hydrate.

An experimental study was carried out to convert carbohydrates using bimetal modified beta zeolite to obtain a maximum yield of lactic acid.     

Anisotropic tough poly(vinyl alcohol)/graphene oxide nanocomposite hydrogels for potential biomedical applications

Hydrogels, one of the most important bioinspired materials, are receiving increasing attention because of their potential applications as scaffolds for artificial tissue engineering and vehicles for drug delivery, etc. However, these applications are always severely limited by their microstructure and mechanical behavior. Here we report the fabrication of a tough polyvinyl alcohol/graphene oxide (PVA/GO) nanocomposite hydrogel through a simple and effective directional freezing–thawing (DFT) technique. The resulting hydrogels show well-developed anisotropic microstructure and excellent mechanical properties with the assistance of DFT method and lamellar graphene. The hydrogels with anisotropic porous structures that consisted of micro-sized fibers and lamellas exhibit high tensile strengths, up to 1.85 MPa with a water content of 90%. More interestingly, the PVA/GO composite hydrogels exhibit the better thermostability, which can maintain the original shape when swollen in hot water (65 °C). In addition, the hydrogels with biocompatibility show good drug release efficiency due to the unique hierarchical structure. The successful synthesis of such hydrogel materials might pave the way to explore applications in biomedical and soft robotics fields.

Tough PVA/GO nanocomposite hydrogel with well-developed anisotropic microstructure and excellent mechanical properties.