Reaction pathways and selectivity in the chemo-catalytic conversion of cellulose and its derivatives to ethylene glycol:A review

Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivatives of cellulose conversion to ethylene glycol,and it is found that studying the reaction process of both can help to understand the reaction mechanism of cellulose.It is desirable to develop a reusable,highly active catalyst to convert cellulose into ethylene glycol.This ideal catalyst might have one or more active sites described the conversion steps above.Here,we discuss the catalyst development of celluloseto-ethylene glycol,including tungsten,tin,lanthanide,and other transition metal catalysts,and special attention is given to the reaction mechanism and kinetics for preparing ethylene glycol from cellulose,and the economic advantages of biomass-to-ethylene glycol are briefly introduced.The insights given in this review will facilitate further development of efficient catalysts,for addressing the global energy crisis and climate change related to the use of fossil fuels.

Vertically aligned montmorillonite aerogel-encapsulated polyethylene glycol with directional heat transfer paths for efficient solar thermal energy harvesting and storage

The conversion and storage of photothermal energy using phase change materials(PCMs)represent an optimal approach for harnessing clean and sustainable solar energy.Herein,we encapsulated polyethylene glycol(PEG)in montmorillonite aerogels(3D-Mt)through vacuum impregnation to prepare 3D-Mt/PEG composite PCMs.When used as a support matrix,3D-Mt can effectively prevent PEG leakage and act as a flame-retardant barrier to reduce the flammability of PEG.Simultaneously,3D-Mt/PEG demonstrates outstanding shape retention,increased thermal energy storage density,and commendable thermal and chemical stability.The phase transition enthalpy of 3D-Mt/PEG can reach 167.53 J/g and remains stable even after 50 heating-cooling cycles.Furthermore,the vertical sheet-like structure of 3D-Mt establishes directional heat transport channels,facilitating efficient phonon transfer.This configuration results in highly anisotropic thermal conductivities that ensure swift thermal responses and efficient heat conduction.This study addresses the shortcomings of PCMs,including the issues of leakage and inadequate flame retardancy.It achieves the development and design of 3D-Mt/PEG with ultrahigh strength,superior flame retardancy,and directional heat transfer.Therefore,this work offers a design strategy for the preparation of high-performance composite PCMs.The 3D-Mt/PEG with vertically aligned and well-ordered array structure developed in this research shows great potential for thermal management and photothermal conversion applications.

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripheral nerve allografts undergo immunological rejection by the host immune system.In contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian degeneration.The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study.We hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery.We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion.Ablation-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons.Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively.Other morphological signs of rejection,such as collapsed Schwann cell basal lamina tubes,were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively.Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts.While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts,loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively.MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts,but MHCII expression was modestly lower compared to negative control at 21 days postoperatively.We conclude that,while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts,successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts,and produce recovery of sensory/motor functions and voluntary behaviors.Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

Hyponatremic encephalopathy due to polyethylene glycol-based bowel preparation for colonoscopy:A case report

BACKGROUND Adequate bowel preparation is critical for colonoscopy screening.At present,the most widely used intestinal cleaner recommended at home and abroad is Polyethylene glycol(PEG).Intestinal cleansers can cause electrolyte disturbances and hyponatremia.However,hyponatremic encephalopathy due to hyponatremia induced by PEG solution,although rare,can lead to serious irreversible sequelae and even death.CASE SUMMARY In this report,we discuss a case of neurological dysfunction due to hyponatremia,also known as hyponatremic encephalopathy,observed in a 63-year-old woman who underwent PEG-based bowel preparation for colonoscopy.She was eventually transferred to our intensive care unit for treatment due to her Glasgow Coma Scale score of 9/15(Eye opening 2;Verbal response 1;Motor response 6)and abnormal laboratory tests.CONCLUSION Physicians should be thoroughly familiarized with the patient’s history before prescribing PEG for bowel preparation,and timely identification of patients with hyponatremic encephalopathy is essential as delayed treatment is associated with poor neurological outcomes.An intravenous infusion of 3%sodium chloride is recommended at the onset of early symptoms.The goal of treatment is to adequately treat cerebral edema while avoiding serum sodium correction beyond 15 to 20 m Eq/L within 48 h of treatment to prevent osmotic demyelination syndrome.

Emerging space for non-polyethene-glycol bowel preparations in inflammatory bowel disease-related colonoscopy:Veering toward better adherence and palatability

Patients with inflammatory bowel diseases(IBDs)require repeated endoscopic evaluations over time by colonoscopy to weigh disease activity but also for different and additional indications(e.g.,evaluation of postoperative recurrence,colorectal cancer surveillance).Colonoscopy,however,requires adequate bowel preparation to be of quality.The latter is achieved as long as the patient takes a certain amount of product to have a number of bowel movements suitable to clean the colon and allow optimal visualization of the mucosa during endoscopy.However,significant guidelines recommend preparations for patients with IBD not excelling in palatability.This recommendation originates from the fact that most of the studies conducted on bowel preparations in patients with IBD have been done with isosmolar preparations based on polyethylene glycol(PEG),for which,therefore,more safety data exist.As a result,the low-volume non-PEG preparations(e.g.,magnesium citrate plus picosulphate,oral sulphate solutions)have been set aside for the whole range of warnings to be heeded because of their hyperosmolarity.New studies,however,are emerging,leaning in overall for a paradigm shift in this matter.Indeed,such non-PEG preparations seem to show a particularly encouraging and engaging safety profile when considering their broad potential for tolerability and patient preference.Indeed,such evidence is insufficient to indicate such preparations in all patients with IBD but may pave the way for those with remission or well-controlled disease.This article summarizes the central studies conducted in IBD settings using non-PEG preparations by discussing their results.

Analysis of Ethylene Glycol Degumming Process and Characterization of Hemp Fibers

To overcome the shortcomings of traditional degumming process,an efficient and environmentally friendly ethylene glycol(EG) degumming process was adopted to degum hemp fibers.The surface morphology,chemical composition,chemical structures,and mechanical properties of the fiber samples were analyzed to explore the mechanism of the degumming process.It was found that the EG degumming process could be divided into the main degumming stage(heating) and the supplementary degumming stage(insulation).The removal rates of hemicellulose and lignin in the main degumming stage were 70.56% and 60.17%,respectively.In the supplementary degumming stage,9.95% hemicellulose and 25.39% lignin were removed.It is confirmed that EG can separate hemp fibers effectively with less damage,which holds great potential for the biomass fiber separation technology.

Manipulating Zn^(2+)solvation environment in poly(propylene glycol)-based aqueous Li^(+)/Zn^(2+)electrolytes for high-voltage hybrid ion batteries

Compared with aqueous single-ion batteries,rechargeable aqueous hybrid ion batteries,especially Li^(+)/Zn^(2+)hybrid ion batteries,are receiving extensive interest owing to their low cost,high operating voltage,and energy density.However,their working voltage and lifespan are limited by the decomposition of water and the growth of Zn dendrites.Herein,detrimental side reactions induced by the water reduction and the Zn dendrite growth are successfully suppressed by a poly(propylene glycol)(PPG)-based hybrid ion electrolyte[(1 m Zn(TFSI)2+10 m LiTFSI)in PPG/H2O].The addition of PPG in the electrolyte can not only enhance the bonding strength of hydrogen-bond in water but also tailor the solvation sheath of Zn2+as revealed by synchrotron X-rays.The participated solvation of PPG with Zn^(2+)can weaken Zn-H_(2)O interactions and redistribute Zn^(2+)flux on the surface of the Zn anode,thus inducing favorably even deposition of Zn.In addition,the decomposition of TFSI-contributes a ZnF_(2)-enriched solid electrolyte interface at the Zn anode to further prevent water decomposition and restrain Zn dendrites.The PPG-based electrolyte enables 2.1 V LiMnO_(2)//Zn batteries to deliver high specific capacities(121.7 mAh g^(-1)for a coin cell and 90 mAh g^(-1)for a pouch cell),and maintain 80%of the capacity over 700 cycles at 0.5 C,suggesting a promising pathway for highly reversible aqueous hybrid ion batteries.

Solubility study and selective purification of HMX explosive in organic electrolyte solution of zinc acetate/diethylene glycol

In this study, an organic electrolyte solution based on zinc acetate/diethylene glycol(ZA/DEG) is introduced for the selective purification of cyclotetramethylene tetranitramine(HMX) high explosive from its identical homologue cyclotrimethylene trinitramine(RDX). The dielectric constant of various organic solutions were investigated through Electrochemical Impedance Spectroscopy(EIS) in the range of 1.0 Hz—30 MHz. and some quantum-chemical descriptors of RDX and HMX dissolutions in the ZA cosolvent were analyzed using Density Functional Theory(DFT). The results show dielectric constant and solubility of RDX is higher than that of HMX, and by increasing of ZA concentration in DEG solvent, the values of dielectric constants were enhanced. Furthermore, the presence of ZA cosolvent on the solubility of two explosives was statistically investigated by Central Composite Design(CCD) of experiment, and some solubility parameters including activity coefficient, dissolving enthalpy, and mixing enthalpies were determined. The experimental results indicate that the weight ratio of RDX to HMX solubility in the proposed organic electrolyte changes up to 30 times, which provides a selective and sequential separation method to separate two materials with similar chemical properties with a separation efficiency>98% and HMX purity> 99.8%. The X-Ray Diffraction(XRD) analysis, High-Performance Liquid Chromatography(HPLC), Laser-Induced Breakdown Spectroscopy(LIBS), and Fourier Transform Infrared Spectroscopy(FT-IR) approves the acceptable quality of the separated materials. The proposed method makes the efficient and safe purification of high-quality HMX for application in oil and gas well perforating gun charges, using a nonvolatile and inflammable organic electrolyte.

Study of Thermal,Phase Morphological and Mechanical Properties of Poly(L-lactide)-b-Poly(ethylene glycol)-b-Poly(L-lactide)/Poly(ethylene glycol)Blend Bioplastics

A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applications.In this work,a PEG was incorporated into block copolymer as a plasticizer by solvent casting.PLLA-PEG-PLLA/PEG blends with different blend ratios were prepared,and the plasticizing effect and miscibility of PEG in block copolymer were intensively investigated compared to PLLA/PEG blends.The results indicated that the PEG was an effective plasticizer for the block copolymer.The blending of PEG decreased glass-transition temperature and accelerated the crystallization of both the PLLA and PLLA-PEG-PLLA matrices.The PEG was completely miscible when blended with block copolymer and it improved thermal stability of the block copolymer matrix but not of the PLLA matrix.Film extensibility of PLLA-PEG-PLLA/PEG blends steadily increased as the PEG ratio increased.These non-toxic and highly flexible PLLA-PEG-PLLA/PEG bioplastics are promising candidates for several applications such as biomedical devices,tissue scaffolds and packaging materials.

Polyethylene glycol crosslinked decellularized single liver lobe scaffolds with vascular endothelial growth factor promotes angiogenesis in vivo

Background: Improving the mechanical properties and angiogenesis of acellular scaffolds before transplantation is an important challenge facing the development of acellular liver grafts. The present study aimed to evaluate the cytotoxicity and angiogenesis of polyethylene glycol(PEG) crosslinked decellularized single liver lobe scaffolds(DLSs), and establish its suitability as a graft for long-term liver tissue engineering. Methods: Using mercaptoacrylate produced by the Michael addition reaction, DLSs were first modified using N-succinimidyl S-acetylthioacetate(SATA), followed by cross-linking with PEG as well as vascular endothelial growth factor(VEGF). The optimal concentration of agents and time of the individual steps were identified in this procedure through biomechanical testing and morphological analysis. Subsequently, human umbilical vein endothelial cells(HUVECs) were seeded on the PEG crosslinked scaffolds to detect the proliferation and viability of cells. The scaffolds were then transplanted into the subcutaneous tissue of Sprague-Dawley rats to evaluate angiogenesis. In addition, the average number of blood vessels was evaluated in the grafts with or without PEG at days 7, 14, and 21 after implantation. Results: The PEG crosslinked DLS maintained their three-dimensional structure and were more translucent after decellularization than native DLS, which presented a denser and more porous network structure. The results for Young’s modulus proved that the mechanical properties of 0.5 PEG crosslinked DLS were the best and close to that of native livers. The PEG-VEGF-DLS could better promote cell proliferation and differentiation of HUVECs compared with the groups without PEG cross-linking. Importantly, the average density of blood vessels was higher in the PEG-VEGF-DLS than that in other groups at days 7, 14, and 21 after implantation in vivo. Conclusions: The PEG crosslinked DLS with VEGF could improve the biomechanical properties of native DLS, and most importantly, their lack of cytotoxicity provides a new route to promote the proliferation of cells in vitro and angiogenesis in vivo in liver tissue engineering.

Stability and Thermal Property Optimization of Propylene Glycol-Based MWCNT Nanofluids

Propylene glycol-based MWCNT(multi-walled carbon nanotubes)nanofluids were prepared in the framework of a two-step method and by using a suitable PVP(polyvinyl pyrrolidone)dispersant.The BBD(Box-Behnken design)model was exploited to analyze 17 sets of experiments and examine the sensitivity of the absorbance to three parameters,namely the concentration of MWCNT,the SN ratio(mass ratio of carbon nanotubes to sur-factants)and the sonication time.The results have revealed that,while the SN ratio and concentration of MWCNT have a strong effect on the absorbance,the influence of the sonication time is less important.The sta-tistical method of analysis of variance(ANOVA)was further used to determine the F-and p-values of the model.Five experiments were run to validate this approach.Since sample 2 was found to display the greatest absorbance,it was selected for stability monitoring as well as thermal conductivity and viscosity measurements.This sample has been found to be stable;the viscosity decreased with increasing temperature;the addition of MWCNT nano-particles was more effective in improving the thermal conductivity of propylene glycol than other methods in the literature.Moreover,the MWCNT nanofluid based on propylene glycol exhibited higher thermal conductivity at low temperatures.

Preparation and Thermo-Responsive Properties of Poly(Oligo(Ethylene Glycol)Methacrylate)Copolymers with Hydroxy-Terminated Side Chain

Thermo-responsive random copolymers,poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-(ethylene glycol)methyl ether methacrylate)(P(EO_(2)-co-EO_(4/5)))and poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-ethylene glycol methacrylate(P(EO2-co-EG4/5))are synthesized via atom transfer radical polymerization(ATRP).The successful synthesis and the narrow polydispersity index(PDI)of two copolymers are indicated by 1H nuclear magnetic resonance(1H-NMR)and gel permeation chromatography(GPC)analyses.The transition behaviors of polymers in the aqueous solution are demonstrated by changes in turbidity and particle sizes.The transition behavior of P(EO2-co-EG4/5)is found to be milder than that of P(EO2-co-EO4/5).Moreover,the presence of hydrogen bonds without thermo-responsive properties established by hydroxyl groups in the end-side chain of P(EO_(2)-co-EG_(4/5))hinders the dehydration at the transition temperature(TT).Attenuated total reflection Fourier transform infrared spectrometry(ATR-FTIR)analysis along with contact angle measurements reveals that both P(EO_(2)-co-EO_(4/5))and P(EO_(2)-co-EG_(4/5))films undergo phase transitions from hydrophilicity to hydrophobicity above TT.By examining the swelling and collapse behaviors of the polymer films during phase transitions,it can be concluded that the end hydroxyl groups may establish hydrogen bonds with neighboring ether groups within the films,which remain intact throughout the phase transition process due to their strong bonding interactions.This leads to an increase in steric hindrance within swollen films thereby impeding dehydration processes and inducing hysteresis during phase transitions.

Anaphylactic shock induced by polyethylene glycol after bowel preparation for the colorectal cancer surgery:A case report

BACKGROUND Polyethylene glycol(PEG)is widely used as an additive because of its hydrophilic and chemically inert properties.However,there are been increasing reports of PEG allergies,including anaphylaxis,although they are still rare.This case report aims to raise awareness,that the commonly used bowel cleansing agent containing PEG can cause serious allergic reactions.CASE SUMMARY Prior to surgery for sigmoid colon cancer,a 63-year-old man was prescribed a bowel cleansing agent containing PEG.Within 30 min of ingestion,he developed symptoms of anaphylactic shock and did not respond to initial intramuscular epinephrine injection.Under diagnosis of anaphylaxis to PEG,he was stabilized with fluid hydration and continuous norepinephrine infusion.CONCLUSION While allergic reactions to PEG are rare,they can be life-threatening.Therefore,it is crucial for clinicians to be aware of this possibility and to diagnose and resuscitate patients immediately.

Significance of Nanoparticles Aggregation with Cattaneo-Christov Heat Flux on the Water and Ethylene Glycol Mixture Based MWCNTs-Nanofluid Flow over a Stretching Cylinder

This work aims to analyze the flow of electrically conducting MWCNTs-nanofluid over a stretching cylinder with the aggregation and non-aggregation effects of nanoparticles. The working fluid comprised a combination of water and ethylene glycol, with volumetric proportions of (50:50) considered. Convective boundary constraints and modified Fourier law are implemented in heat transmission assessment. The mathematical flow model is formulated in the form of PDEs and is transformed into ODEs via similarity transformation. Numerical outcomes will be obtained with the use of the bvp4c technique and will be displayed with the help of graphs and tables. The results show that the surface drag coefficient is enhanced in the case of aggregation of nanoparticles whereas heat transfer rate is enhanced in the non-aggregation effect of nanoparticles. Furthermore, the temperature distribution enhances the increasing values of particle volume fraction in the case of aggregation effects of nanoparticles whereas temperature distribution lowers in the case of non-aggregation effect of nanoparticles. .

2 L聚乙二醇方案肠道准备的“真实世界”研究

目的基于“真实世界”研究2 L复方聚乙二醇电解质溶液(PEG)在结肠镜检查前肠道准备时的应用效果。方法选取2022年11月至2023年4月在我院消化内镜中心使用2 L PEG方案进行肠道准备的4268例患者,根据波士顿肠道准备量表(BBPS)对总体、各段结肠的清洗结果进行评分,按照是否合格分为合格组(n=3802)和不合格组(n=466)。比较两组的危险因素、依从性及患者感受等。结果在使用PEG进行肠道准备的4268例检查者中,3802例合格(合格率89.1%),466例不合格(不合格率10.9%)。BBPS总评分为(6.60±1.10)分,右侧结肠评分为(2.05±0.48)分,横结肠评分为(2.45±0.55)分,左侧结肠为(2.10±0.45)分。息肉总体检出率为51.6%(2203/4268)。进行多因素Logistic回归方程分析,结果显示,男性、胃肠道外科手术史、糖尿病史、每周排便<3次均为导致结肠镜检查前肠道准备不合格的危险因素(均OR>1,P<0.05)。结论2 L PEG方案能够基本满足中国人结肠镜检查肠道准备的需求,对于男性、胃肠道外科手术史、糖尿病史、每周排便<3次的检查者需要进行更严格的肠道准备方式。

聚乙二醇修饰杨梅苷固体脂质纳米粒制备及其体内药动学研究

目的制备聚乙二醇修饰杨梅苷固体脂质纳米粒,并考察其体内药动学。方法高压均质法制备聚乙二醇修饰固体脂质纳米粒,测定包封率、载药量、粒径、Zeta电位,单因素试验优化处方,XRPD进行晶型分析,考察体外释药、稳定性。24只大鼠随机分为4组,分别灌胃给予杨梅苷、杨梅苷固体脂质纳米粒、杨梅苷固体脂质纳米粒+聚乙二醇硬脂酸酯、聚乙二醇修饰杨梅苷固体脂质纳米粒的0.5%CMC-Na混悬液(150 mg/kg),于不同时间点采血,HPLC法测定杨梅素血药浓度,计算主要药动学参数。结果最优处方为药脂比1∶15,单硬酯酸甘油酯与聚乙二醇硬脂酸酯比例10∶1,泊洛沙姆188浓度0.8%,均质次数8次,包封率为81.75%,载药量为5.04%,粒径为207.56 nm,PDI为0.092,Zeta电位为-14.79 mV。杨梅苷以无定型状态存在于聚乙二醇修饰固体脂质纳米粒中,18 h内累积释放度为64.71%,模拟胃液中2 h内、模拟肠液中12 h内稳定性良好。与原料药、固体脂质纳米粒比较,聚乙二醇修饰固体脂质纳米粒t_(max)延长(P<0.05),C_(max)、AUC_(0~t)、AUC_(0~∞)升高(P<0.05,P<0.01),相对生物利用度与原料药相比增加至4.60倍。结论聚乙二醇修饰固体脂质纳米粒可改善杨梅苷稳定性,促进其口服吸收。

PLGA纳米粒及其在生物医学领域的应用潜力

聚乳酸-羟基乙酸(polylactic-co-glycolic acid, PLGA)是由单体乳酸和羟基乙酸构成的具有良好的可降解性和生物相容性的高分子聚合物,其作为新型载体和传递系统被广泛应用于生物学和医药学等领域。PLGA具有抗原展示和抗原包裹的功能,能保护包裹包括生物活性化合物(如蛋白质和多肽)、核酸及免疫调节分子在内的一系列物质,免受蛋白酶介导的黏膜表面降解,还能使药物或抗原缓慢释放,以减少免疫和用药次数,在肠道疾病治疗上有巨大的应用潜力。此外,还可将药物或抗原偶联到PLGA纳米粒表面起到抗原展示的作用,在疫苗研发和药物制备方面表现出优异特性。PLGA还可作为佐剂,增强疫苗的免疫保护效果。PLGA的表面修饰功能可用于药物的靶向递送,靶向递送治疗分子到身体的特定部位,既可减少不良副作用,同时还可提高局部原料药的浓度来提高药物疗效,是生物医学研究的一个活跃领域。PLGA纳米粒可单独或联合装载不同类型的药物,免疫原性小,且易于通过受控的化学合成进行调节,因此,PLGA作为生物医学领域应用潜力巨大的非病毒基因传递系统和药物传递平台,广泛用于疫苗制备和药物研发等领域。笔者重点综述了PLGA纳米粒的结构特征和制备方法,以及基于PLGA制备的纳米载体平台在疫苗研发和药物递送等领域的研究进展及应用前景,旨在为PLGA纳米粒的相关研究提供参考。

干旱指数法综合评价河南烤烟新品种抗旱性

以中烟100、云烟87和NC89为对照品种,采用PEG(聚乙二醇)模拟干旱试验,结合盆栽控水试验研究干旱胁迫对河南省烤烟新品种的影响,采用干旱指数法综合评价新品种的抗旱性。结果表明,河洛1号抗旱性最强;其次是豫浓香201,在中度干旱胁迫条件下抗旱性较强,重度干旱则影响烟叶正常生长;渠首1号抗旱性与对照品种NC89、中烟100和云烟87基本相当。

氯化胆碱-乙二醇-水溶液制备镍铁氧体

以氯化胆碱-乙二醇(ChCl-EG)和水混合溶液为介质,依据三因素五水平均匀设计实验方案,采用溶胶/凝胶-自蔓延法,制备了镍铁氧体(NiFe_(2)O_(4))。X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和振动样品磁强计(VSM)分析结果表明:NiFe_(2)O_(4)中存在少量前驱体焙烧过程中未反应完全的中间产物NiO和α-Fe_(2)O_(3);相较于传统水溶剂制备的NiFe_(2)O_(4),以ChCl-EG部分或完全取代水溶剂提高了NiFe_(2)O_(4)的饱和磁化强度(Ms),降低了其矫顽力(Hc)。扫描电子显微镜(SEM)分析结果表明,ChCl-EG完全取代水溶剂后产物的形貌更加规整,颗粒尺寸明显增大。对均匀实验结果进行回归分析,分别得到了M_(s)、H_(c)与合成主要影响因素(ChCl-EG含量、pH、柠檬酸与金属离子物质的量比)间的回归方程,根据回归方程阐明了主要影响因素对NiFe_(2)O_(4)磁性能的影响。

储气库注采工艺优化研究与应用

储气库建设对供气管网安全、平衡供气具有重要战略意义,在天然气调峰中起到举足轻重的作用。目前,储气库工艺存在压缩机组中体放空对空排放安全隐患和增压气润滑油超标、采出气轻烃超标、甘醇再生系统尾气对空排放、集输管线积盐腐蚀等问题。针对中体放空,设置放空引射装置,将排放物引至火炬集中排放,避免可燃气体站内聚集的隐患;针对润滑油含量超标(体积比为16×10^(−6)),设置高压除油器,降低增压气油含量,消除二次污染;通过对脱水装置吸收塔和再生装置优化,避免甘醇起泡失活;通过对甘醇再生气系统改造,实现再生气回收利用,降低环境污染,节约能耗。