Synthesis and Characterization of Carboxyl-terminated Polyethylene Glycol Functionalized Mesoporous Silica Nanoparticles

Colloidal mesoporous silica nanoparticles functionalized with carboxy-terminated polyethylene glycol(CMS-PEG-COOH) were successfully synthesized by covalently grafting dicarboxy-terminated polyethylene glycol(HOOC-PEG-COOH) on the surface of the amino functionalized CMS nanoparticles with amide bond as a cross linker. Moreover, the structural and particle properties of CMS-PEG-COOH were characterized by nuclear magnetic resonance spectroscopy(1 H-NMR), transmission electron microscopy(TEM), dynamic light scattering(DLS), nitrogen adsorption-desorption measurements, X-ray diffraction(XRD), and Fourier transform infrared spectroscopy(FT-IR). The nanomaterials presented a relatively uniform spherical shape morphology with diameters of about 120 nm,and favorable dispersibility in weak acid solution. The CMSPEG-COOH exhibited no changes in the state of amorphous, while the mesopores sizes of 5.25 nm might provide the nanomaterials with large capacity for the loading and releasing of drugs. So the results indicated that CMSPEG-COOH might be a critical nanomaterial for drug delivery system in the future.

Predictive functional control （PFC） and its application in chlorinated polyethylene process

The main principle and the characteristic of Predictive Functional Control (PFC) strategy are presented in this paper and the corresponding control system aid design software APC-PFC is also introduced. For a chlorinated polyethylene (CPE) process, a design scheme of cascade predictive functional control system is described and the control performance is improved obviously.

Comparison of the chloride channel activator lubiprostone and the oral laxative Polyethylene Glycol 3350 on mucosal barrier repair in ischemic-injured porcine intestine

AIM： To investigate the effects of lubiprostone and Polyethylene Glycol 3350 （PEG） on mucosal barrier repair in ischernic-injured porcine intestine. METHODS： Ileum from 6 piglets （approximately 15 kg body weight） was subjected to ischemic conditions by occluding the local rnesenteric circulation for 45 min in vivo. Ileal tissues from each pig were then harvested and mounted in Ussing chambers and bathed in oxygenated Ringer＇s solution in vitro. Intestinal barrier function was assessed by measuring transepithelial electrical resistance （TER） and mucosal-to-serosal fluxes of ^3H-rnannitol and ^14C-inulin. Statistical analyses of data collected over a 120-min time course included 2-way ANOVA for the effects of time and treatment on indices of barrier function. RESULTS： Application of 1μmol/L lubiprostone to the rnucosal surface of ischemic-injured ileum in vitro induced significant elevations in TER compared to nontreated tissue. Lubiprostone also reduced mucosal-toserosal fluxes of ^3H-rnannitol and ^14C-inulin. Alternatively, application of a polyethylene laxative （PEG, 20 rnmol/L） to the mucosal surface of ischernic tissues significantly increased flux of ^3H-rnannitol and ^14C-inulin. CONCLUSION： This experiment demonstrates that lubiprostone stimulates recovery of barrier function in ischemic intestinal tissues whereas the PEG laxative had deleterious effects on mucosal repair. These results suggest that, unlike osmotic laxatives, lubiprostone stimulates repair of the injured intestinal barrier.

Studies on Kinetics of Chlorination Reaction of Polyethylene

Through kinetic method, the reaction mechanism and the rate equations of chlorination of polyethylene are suggested in this paper. The rate of chlorination is second order with respect to the concentration of methylene remained and chlorine, respectively. Apparent changes in crystallinity during chlorination processes were determinated by differential scanning calorimetry(DSC). The mathematical model relating crystallinety with kinetic parameters and function of sequence length distribution are derived.

SIMULATION MODELING ON THE COORDINATION MECHANISM OF ETHYLENE MONOMER ON VARIOUS PREREDUCED Cr（Ⅱ）Ox/SiO2 PHILLIPS POLYETHYLENE MODEL CATALYSTS

As one of the most important catalysts in polyethylene industry,Phillips catalyst(CrO_x/SiO_2)was quite unique for its activation by ethylene monomer without using any activator like alkyl-aluminium or MAO.In this work,the density functional theory(DFT)calculation combined with paired interacting orbitals(PIO)method was applied for the theoretical studies on coordination reaction mechanism between ethylene monomer and two model catalysts namely Cr(Ⅱ)(OH)_2(M1) and silsesquioxane-supported Cr(Ⅱ)(M2)as surfac...

Chemical Modification and Characterization of Multi-Walled Carbon Nanotubes Using Octadecylamine and Polyethylene Glycol

Chemical modification of MWCNTs via oxidation followed by side wall functionalization using polyethylene glycol （PEG） and octadecylamine （ODA）, separately, was studied. Different characterization techniques such as FTIR spectrometery, thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and solubility in different solvents were performed for the oxidized MWCNTs, MWCNTs-PEG and MWCNTs-ODA. The characterization techniques proved the presence of the functional groups on the MWCNTs surface. Thermal gravimetric analysis revealed that nearly 16% （by weight） of the MWCNTs were functionalized with PEG and 39% （by weight） was functionalized with ODA.

乙烯与乙烯基三乙氧基硅烷共聚物的制备与表征

采用一系列结构不同的α-二亚胺镍催化剂,在倍半乙基氯化铝(EASC)作用下,以配位共聚的方法制备乙烯和乙烯基三乙氧基硅烷(VTEoS)共聚物。研究了VTEoS的浓度、催化剂用量、n(Al)/n(Ni)、乙烯压力、聚合时间、溶剂以及催化剂结构对共聚反应的影响,得到了最优化的聚合条件。通过核磁共振(NMR)、哀减全反射傅里叶变换红外光谱(ATR-FTIR)、热失重分析(TGA)、焙烧法、聚合物膜的接触角测试等方法分别表征了聚合物的结构、热稳定性、硅质量分数和聚合物膜的表面性能。结果表明,以C4为催化剂,二氯甲烷为溶剂时,共聚活性(以1 mol Ni计)最高达9.10×10^(5) g/(mol·h),共聚物中硅的质量分数为0.74%~3.39%。含硅单体的引入,能够提高聚合物的热稳定性和疏水性能。

含抗泥功能单体的聚羧酸减水剂的制备及抗泥性能

采用聚乙二醇400(PEG400)合成了一种新型抗泥功能单体(FM),并将其引入到聚羧酸减水剂(PCE)的分子结构上,制备了几种抗泥型聚羧酸减水剂(AC-PCE)。采用傅里叶红外光谱(FT-IR)对FM和PCE进行表征,分别通过净浆流动度和砂浆流变性试验考察PCE在含蒙脱土(MMT)水泥净浆和水泥砂浆中的分散性能,并研究了PCE在MMT上的吸附特性。结果显示,与不含FM的聚羧酸减水剂相比,AC-PCE减少了在MMT上的吸附量,抑制了MMT的插层吸附,降低了含MMT水泥净浆经时流动度损失以及含MMT水泥砂浆的屈服应力。研究表明,AC-PCE具有良好的抗泥性能。

Constipation and colonoscopy

Constipation is a significant sociomedical problem,which can be caused by various reasons.In the diagnostic approach to patients with constipation,the following data are usually sufficient:History,complete physical examination(including rectal examination),and additional diagnostic tests.A colonoscopy is not a necessary diagnostic method for all patients with constipation.However,if patients have alarm symptoms/signs,that suggest an organic reason for constipation,a colonoscopy is necessary.The most important alarm symptoms/signs are age>50 years,gastrointestinal bleeding,new-onset constipation,a palpable mass in the abdomen and rectum,weight loss,anemia,inflammatory bowel disease,and family history positive for colorectal cancer.Most endoscopists do not like to deal with patients with constipation.There are two reasons for this,namely the difficulty of endoscopy and the adequacy of preparation.Both are adversely affected by constipation.To improve the quality of colonoscopy in these patients,good examination techniques and often more extensive preparation are necessary.Good colonoscopy technique implies adequate psychological preparation of the patient,careful insertion of the endoscope with minimal insufflation,and early detection and resolution of loops.Bowel preparation for colonoscopy often requires prolonged preparation and sometimes the addition of other laxatives.

聚乙二醇对婴幼儿功能性便秘的改善及生长发育的影响

目的探讨高剂量聚乙二醇(polyethylene glycol,PEG)对婴幼儿功能性便秘(functional consitipation,FC)的改善及对患儿生长发育的影响。方法选取2022年10月—2023年7月西宁市第一人民医院收治的FC患儿130例,按照随机数字表法分为参照组(65例)和研究组(65例),参照组给予乳果糖口服溶液进行治疗,研究组给予高剂量PEG进行治疗,观察治疗前后两组排便次数、Bristol分型评分、症状缓解情况、生长发育情况、临床疗效及不良反应发生情况。结果治疗后研究组排便次数、Bristol分型评分、患儿身高、体质量及总有效率[分别为(5.58±0.62)次,(3.53±1.15)分,(87.48±8.76)cm,(14.38±2.15)kg,98.46%]均高于参照组[分别为(4.42±0.59)次,(2.63±1.02)分,(75.22±8.58)cm,(11.27±2.21)kg,89.23%],差异均具有统计学意义(均P<0.05);研究组腹胀、便痛、排便困难、食欲不振评分[分别为(3.69±1.32)分,(2.11±2.10)分,(2.79±0.72)分,(2.99±1.58)分]均低于参照组[分别为(4.56±1.15)分,(3.78±2.09)分,(4.04±0.69)分,(4.83±1.47)分],差异均具有统计学意义(均P<0.05)。结论高剂量PEG治疗婴幼儿FC,能够改善患儿便秘情况及生长发育状况,且疗效较佳。

高空隙轻盈聚酯纤维的工艺研究

在聚合工艺的酯化-缩聚阶段添加超细硅藻土等助剂制备舒适性聚酯熔体,在前述共聚酯中添加了一定比例的水溶性聚酯,使用具有异形喷丝孔的纺丝组件,纺制具有十字形截面的聚酯纤维。用热稀碱溶液将前述纤维中的水溶性聚酯挖蚀溶解,在纤维表面至内部形成高空隙蜂窝状态,这些蜂窝状空隙使纤维密度大幅度下降的同时透气透湿性能也明显增加。研究结果表明,该工艺制造的高空隙聚酯纤维透气导湿性能优良,纤维形成的织物舒适、蓬松、轻盈。

聚乙二醇洛塞那肽与利拉鲁肽治疗肥胖2型糖尿病疗效对比

目的通过比较聚乙二醇洛塞那肽与利拉鲁肽治疗肥胖2型糖尿病的疗效,为临床治疗该类疾病选择更高效的用药方案。方法选取东南大学医学院附属南京同仁医院2022年1月至2023年10月予以相应治疗的肥胖2型糖尿病患者共136例作为此次试验对象,按照随机数字表法分成68例A组(聚乙二醇洛塞那肽治疗)与68例B组(利拉鲁肽治疗)。比较治疗前后两组肥胖相关指标、治疗前后两组血脂相关指标、治疗前后两组血糖指标以及治疗后不良反应发生率。结果治疗后两组体质量、腰臀比、体质量指数(BMI)和腰围均下降,B组体质量和BMI[分别为(80.31±7.62)kg和(24.13±1.82)kg·m^(-2)]低于A组体质量[分别为(83.65±7.93)kg和BMI(25.34±1.84)kg·m^(-2)](体质量:t=2.504,P=0.014;BMI:t=3.855,P<0.05);治疗后两组甘油三酯(TG)、血清总胆固醇(TC)和低密度脂蛋白(LDL)均下降,高密度脂蛋白胆固醇(HDL-C)上升(均P<0.05);治疗后两组餐后2 h血糖(2 h FBG)、空腹血糖(FBG)、糖化血红蛋白(HbAlc)、胰岛素抵抗指数(HOMA-IR)水平均下降,空腹血糖胰岛素(FINS)、β细胞功能指数(HOMA-β)水平均上升,A组2 h FBG、FBG[分别为(7.86±1.12)mmol·L^(-1)、(6.18±0.71)mmol·L^(-1)]低于B组[分别为2 h FBG(8.72±1.34)mmol·L^(-1)和FBG(7.02±0.62)mmol·L^(-1)](2 h FBG:t=4.061,P<0.05;FBG:t=7.349,P<0.05),A组HOMA-β[(74.62±3.78)%]高于B组[(62.79±3.56)%](t=18.937,P<0.05);两组不良反应发生率比较差异无统计学意义(20.59%vs 25.00%,χ^(2)=0.376,P=0.540)。结论对于肥胖2型糖尿病患者,聚乙二醇洛塞那肽与利拉鲁肽均能有效减轻体质量、调节血脂、降低血糖水平以及增强胰岛β细胞的功能,且安全性相似。然而,在降低体质量方面,利拉鲁肽的效果更为显著,而聚乙二醇洛塞那肽在改善胰岛β细胞功能和降低血糖方面则表现更为出色。

低缠结超高相对分子质量聚乙烯的制备及表征

为解决传统Ziegler-Natta催化剂(简称Z-N催化剂)制备的超高相对分子质量聚乙烯(UHMWPE)缠结程度较高、加工困难等问题,以MgCl_(2)、TiCl_(4)、异辛醇、正硅酸四乙酯(或邻苯二甲酸二己酯)为主要原料,采用化学反应法制备了氯化镁负载型Z-N催化剂cat1(或cat2)。分别以cat1、cat2为主催化剂、三乙基铝为助催化剂,采用淤浆聚合工艺制备了低缠结UHMWPE,测定了cat1、cat2的粒径分布和金属元素质量分数,考察了聚合温度、时间对催化剂催化活性和UHMWPE的黏均相对分子质量(M_(v))的影响,并使用流变分析法和DSC热力学退火法对UHMWPE的缠结程度进行了表征。结果表明,制备的cat1、cat2与设计相符,在聚合反应温度分别为65和70℃、反应5 h时,cat1、cat2催化活性分别达到27700、37700 g PE/g cat,制备的UHMWPE的Mv分别为6.01×10^(6)、5.03×10^(6),起始储能模量分别为0.21、0.13 MPa,缠结程度低于商品化UHMWPE。

Pediatricians lack knowledge for the diagnosis and management of functional constipation in children over 6 mo of age

AIM To assess the knowledge of general pediatricians througout Indonesia about the diagnosis and treatment of childhood constipation.METHODS A comprehensive questionnaire was distributed to general pediatricians from several teaching hospitals and government hospitals all over Indonesia.RESULTS Data were obtained from 100 pediatricians, with a mean of 78.34 ± 18.00 mo clinical practice, from 20 cities throughout Indonesia. Suspicion of constipation in a child over 6 mo of age arises when the child presents with a decreased frequency of bowel movements(according to 87% of participants) with a mean of one bowel movement per 3.59 ± 1.0 d, hard stools(83%), blood in the stools(36%), fecal incontinence(33%), and/or difficulty in defecating(47%). Only 26 pediatricians prescribe pharmacologic treatment as first therapeutic approach, while the vast majority prefers nonpharmacologic treatment, mostly(according to 68%) The preferred nonpharmacologic treatment are high-fiber diet(96%), increased fluid intake(90%), toilet training(74%), and abdominal massage(49%). Duration of non-pharmacological treatment was limited to 1 to 2 wk. Seventy percent of the pediatricians recommending toilet training could only mention some elements of the technique, and only 15% was able to explain it fully and correctly. Lactulose is the most frequent pharmacologic intervention used(87% of the participants), and rectal treatment with sodium citrate, sodium lauryl sulfo acetate, and sorbitol is the most frequent rectal treatment(85%). Only 51% will prescribe rectal treatment for fecal impaction. The majority of the pediatricians(69%) expect a positive response during the first week with a mean(± SD) of 4.1(± 2.56) d. Most participants(86%) treat during one month or even less. And the majority(67%) stops treatment when the frequency and/or consistency of the stools have become normal, or if the patient had no longer complaints.CONCLUSION These data provide an insight on the diagnosis and management of constipation in childhood in Indonesia. Although general pediatricians are aware of some important aspects of the diagnosis and mangement of constipation, overall knowledge is limited. Efforts should be made to improve the distribution of existing guidelines. These findings highlight and confirm the difficulties in spreading existing information from guidelines to general pediatricians.

Synthesis of Hydroxy-functionalized Ultrahigh Molecular Weight Polyethylene Using Fluorenylamidotitanium Complex

Copolymerizations of ethylene and 1-dodecene were conducted with a series of ansa-fluorenylamidodimethyltitanium complexes, [t-BuNSiMe2Flu]TiMe2（1a）, [t-BuNSiMe2（2,7-^tBu2Flu）]TiMe2（1 b）, and [（1-adamantyl）NSiMe2（2,7-^tBu2Flu）]TiMe2（1c） activated by modified methylaluminoxane. The activity increased by the introduction of the alkyl groups on the fluorenyl and amido ligands, and 1c produced the highest molecular weight copolymers. Complex 1c also promoted copolymerization of ethylene and ^iBu3 Al protected 10-undecen-1-ol with high activity（～2000 kg·mol^-1·h^-1）, affording hydroxy-functionalized ultrahigh molecular weight polyethylene. The hydroxy content of the copolymers obtained was controllable by changing comonomer feed ratio. The introduction of a small amount of hydroxy group can alter the surface properties of polyethylene.

载万古霉素聚乙二醇功能化中空介孔硅球缓释药物的制备及其抗菌活性研究

目的:万古霉素是一种具有多重杀菌机制的糖肽类抗菌药物,但因其代谢快和易于产生细菌耐药性等特点,影响其抗菌作用,开发新型基于万古霉素的纳米缓释药物具有重要意义。方法:利用模板法成功制备了聚乙二醇功能化分散性好的中空介孔纳米硅球药物载体,利用红外光谱、透射电镜、动态光散射及热重分析等手段进行了表征分析。结果:该载体对万古霉素的载药量及包封率高达154.9 mg/g和77.5%,24 h万古霉素药物累积释放率为47.4%,细胞存活率均高于85.0%,抗菌活性显著增强。结论:基于中空介孔纳米硅球载体万古霉素药物在药物缓释及生物利用度提升方面具有应用价值,为新型抗菌材料的发展提供了参考。

复方聚乙二醇电解质联合利那洛肽在功能性便秘患者肠镜检查前肠道准备中的应用效果

目的 分析复方聚乙二醇电解质、利那洛肽联合应用对功能性便秘患者肠镜检查前肠道准备中的效果。方法 选取2020年10月至2021年10月浙江省台州市第一人民医院接受肠镜检查的功能性便秘患者155例,根据随机数字表法将其分为对照组(77例)、研究组(78例),对照组采用复方聚乙二醇电解质进行肠道准备,研究组采用复方聚乙二醇电解质联合利那洛肽进行肠道准备。比较两组检查前2 d及检查后1 d的胃肠道症状分级评分量表评分、肠鸣音时间、肛门排气时间,记录两组肠道清洁度、患者主观耐受程度及不良反应。结果 检查后1 d,两组胃肠道症状分级评分量表评分低于检查前2 d,且研究组低于对照组(P<0.05)。检查后1 d,两组肠鸣音时间、肛门排气时间短于检查前2 d,且研究组短于对照组(P<0.05)。研究组患者主观耐受程度及肠道清洁度优于对照组(P<0.05)。两组不良反应总发生率比较,差异无统计学意义(P>0.05)。结论 采用复方聚乙二醇电解质联合利那洛肽方案进行肠镜检查前肠道准备,患者肠蠕动功能得到了有效改善,且肠道清洁能力显著增加,达到了提高患者主观耐受程度的效果。

功能化石墨烯改性聚乙烯热力学特性的分子动力学模拟

聚乙烯绝缘材料在我国高压电缆中有着广泛的应用.为了提高其耐热稳定性和力学性能,利用石墨烯对聚乙烯进行掺杂改性,并基于分子动力学模拟的研究方法分别建立了低密度聚乙烯(LDPE)、石墨烯和3种官能团接枝石墨烯掺杂聚乙烯的复合模型.研究表明,相比石墨烯直接掺杂聚乙烯,羧基(-COOH)、氨基(-NH)和羟基(-OH)接枝石墨烯能够更加有效地提高聚乙烯的玻璃化温度(分别提高了16 K、7 K、5 K),减弱聚乙烯分子链的移动和降低聚乙烯的热膨胀系数、均方位移(MSD),从而使得聚乙烯复合体系的热学性能得到了有效增强.此外发现石墨烯的掺杂能够提高复合模型的力学模量,其中官能团接枝石墨烯改进效果更明显,室温下弹性模量和剪切模量的提升幅度由不接枝的33.98%、36.18%,提升到了44%和42.89%(羧基功能化体系).研究结果可为聚乙烯绝缘材料的热老化抑制和力学性能的改善提供有益的参考.

高密度聚乙烯/硅烷偶联剂改性硫酸钙晶须复合材料的制备与性能

以γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)改性的硫酸钙晶须(CSW)为高密度聚乙烯(HDPE)的填料,采用熔融共混法制备了HDPE/CSW复合材料。通过SEM、XRD、TG、DSC表征了KH570改性的CSW对复合材料HDPE/CSW的性能影响。结果表明,改性CSW质量分数为20%时,HDPE/CSW的拉伸和弯曲强度比纯HDPE分别增加9.28%和33.04%,且易产生异相结晶,提升了HDPE/CSW复合材料的耐热性和结晶度。纯HDPE的热降解反应活化能为244.11 k J/mol,改性CSW质量分数为50%时,HDPE/CSW复合材料的热降解反应活化能降到236.99 kJ/mol,表明CSW提升了HDPE/CSW复合材料的热降解反应速率,扩展了复合材料的使用范围。

聚对苯二甲酸乙二醇酯/SrAl_(2)O_(4):Eu^(2+),Dy^(3+)含杂纤维醇解及其回收产物性能

为提高废弃含杂纤维的回收率,以废弃的聚对苯二甲酸乙二醇酯基含杂纤维(PET/SrAl_(2)O_(4):Eu^(2+),Dy^(3+))为研究对象,采用乙二醇醇解联合热乙醇的方法,探究含杂纤维的醇解性能并回收发光材料SrAl_(2)O_(4):Eu^(2+),Dy^(3+)及PET醇解产物对苯二甲酸双羟乙酯。通过改变乙二醇用量、反应温度及反应时间探讨乙二醇醇解条件对产物性能的影响,借助扫描电子显微镜、X射线衍射仪、差示扫描量热仪、分光光度测色仪、长余辉亮度仪等对醇解产物的微观形貌、物相结构、热稳定性能、余辉性能等进行测试与表征。结果表明:乙二醇用量、反应温度、反应时间和催化剂用量均不会改变发光材料SrAl_(2)O_(4):Eu^(2+),Dy^(3+)的物相结构;当反应温度为190℃,反应时间为180 min时,含杂纤维的醇解率达到100%,此时SrAl_(2)O_(4):Eu^(2+),Dy^(3+)的回收率为93%,初始亮度为3.906 cd/m^(2),对苯二甲酸双羟乙酯的回收率为82%。