聚丙烯酸系列水凝胶的应用

聚丙烯酸是一种水溶性有机高分子,用它开发出的系列水凝胶已经得到了广泛的应用。本文介绍了聚丙烯酸系列水凝胶在吸附剂、吸水保水剂、制退热贴、药物释放及复合成智能水凝胶等方面的应用。     

醇质体及其凝胶与皮肤美容抗衰老制剂

目的:醇质体(Ethosomes)作为近期发现的经皮药物传递载体在临床医学和药学领域已广泛应用,而将它作为面部美容和皮肤抗衰老制剂中功效成分的经皮传递载体,在皮肤抗衰老美容化妆品领域中的应用研究却是鲜为人知。为此,我们通过对目前一些可用于皮肤美容抗衰老醇质体及其凝胶的综述,希望提供一些较为先进和实用的皮肤美容抗衰老新型制剂及其应用研究最新进展给相关学科领域的科学研究者、产晶开发者和使用消费者等参考和借鉴。方法:通过对目前国内外已报道或公布的专利与非专利文献进行系统检索,对当今正在研发和应用的皮肤美容抗衰老醇质体及其凝胶进行专题介绍。结果:采用系统综述和专题介绍的这部分皮肤美容抗衰老醇质体及其凝胶制剂圭耍包括五大部分:第一是细胞生长因子醇质体及其凝胶(rhEGF醇质体及其凝胶和rhaFGF醇质体及其凝胶);第二是天然药物醇质体及其凝胶(GA醇质体及其凝胶、GB醇质体及其凝胶和Arbutin醇质体及其凝胶);第三是自由基清除剂醇质体及其凝胶(VE醇质体及其凝胶和SOD醇质体及其凝胶);第四是抗皮肤光老化醇质体及其凝胶(圭要是ATRA醇质体及其凝胶);第五是雌激素醇质体及其凝胶(炔雌醇醇质体及其凝胶)。结论:实验研究证明,皮肤美容抗衰老醇质体及其凝胶剂是一类性能较好、应用较为理想的新型制剂,特别是它在制备方法上简单、方便、快速、易于操作;在理化特性上粒径小、分散好、包封好、稳定性好;在药学上具有易透皮、渗透好、吸收快,且具有缓释和控释效应等优势;在疗效上具有作用更久、疗效更快、使用更安全等特点。所有这些均提示,它在未来皮肤美容抗衰老方面将具有广阔的应用前景和生命力。但需要说明的是,皮肤美容抗衰老醇质体及其凝胶制剂在美容医学和皮肤抗衰老领域的研究和应用起步不久,对于它的理化特性、制备工艺、剂型剂量、促渗机制、使用安全性、疗效性及生物学效应等尚需进行更加系统探讨和更加深入研究。     

MMA-St共聚凝胶效应临界转化率的确定

在60～90℃范围内,以AIBN和BPO为引发剂,进行甲基丙烯酸甲酯(MMA)—苯乙烯(St)本体共聚,研究了聚合温度、引发剂浓度等因素对共聚反应凝胶效应的影响,比较了几种确定凝胶效应临界转化率的方法。发现各种方法求得的临界转化率实验值与聚合温度及引发剂浓度均有线性关系,并导出了计算各种聚合条件下凝胶效应临界转化率的半经验公式。     

滑动轮凝胶的制备及其结构研究进展

滑动轮凝胶由于其聚合物网络是由8字形的交联结构将聚轮烷拓扑联锁而成,因而具有比传统聚合物凝胶更优越的溶胀性能、延展性以及机械强度,近年来已成为聚合物凝胶领域研究的热点。本文介绍了滑动轮凝胶的基本概念与拓扑交联方式,简述了其优越的性能和广泛的应用价值,回顾了滑动交联理论的提出及实现过程。重点综述了国内外各种滑动轮凝胶的制备方法,以及溶剂、交联密度和环糊精与PEG的包结复合率等因素对其滑轮效应的结构与性能的影响。指出目前滑动轮凝胶所用的聚轮烷骨架种类较少,应用研究有待加强。     

反应性聚合物微凝胶的合成及应用

反应性聚合物微凝胶是一种具有反应活性、分子内交联的高分子,它具有优良的施工性能,涂膜的力学性能及耐久性也十分优异,主要应用于制备高档涂料或对涂料进行改性。本文着重介绍了反应性聚合微凝胶的合成方法及其在涂料改性方面的应用。     

气凝胶复合材料的研究进展

气凝胶材料是一种质轻、低密的多孔材料,对其研究较多。它具有良好的发展前景和巨大的科研价值。通过介绍高分子气凝胶、碳气凝胶等复合材料的制备方法,阐述了结构与性能的关系,并对气凝胶材料未来的发展作了展望。     

凝胶注模成型制备Sialon陶瓷的研究进展

本文系统阐述了凝胶注模成型制备Sialon陶瓷的研究与进展,根据凝胶来源分成非水基凝胶注模体系和水基凝胶注模体系,介绍它们的工艺过程和原理。最后提出了凝胶注模成型制备Sialon陶瓷目前应当注意的问题,并展望了它的前景。     

陶瓷凝胶注模成型技术及其应用研究

凝胶注模成型技术是一种近净尺寸陶瓷成型技术，它为解决陶瓷材料的加工成型问题提供了一条十分有效的工艺途径。介绍了陶瓷凝胶注模成型技术的基本原理和工艺过程，着重介绍了目前凝胶注模成型技术的应用研究。     

凝胶萃取分离技术研究进展

本文较全面地介绍了凝胶萃取分离技术的最新进展．重点介绍温敏、酸敏、电敏型三类凝胶的相变影响因素、溶胀皱缩机理、动力学研究及凝胶的应用等。     

陶瓷凝胶注模成型技术及其应用研究

凝胶注模成型技术是一种近净尺寸陶瓷成型技术,它为解决陶瓷材料的加工成型问题提供了一条十分有效的的工艺途径。介绍了陶瓷凝胶注模成型技术的基本原理和工艺过程,着重介绍了目前凝胶注模成型技术的应用研究。     

Enzymes-Assisted Extraction of Plants for Sustainable and Functional Applications

The scientific community and industrial companies have discovered significant enzyme applications to plant material. This rise imparts to changing consumers’ demands while searching for ‘clean label’ food products, boosting the immune system, uprising resistance to bacterial and fungal diseases, and climate change challenges. First, enzymes were used for enhancing production yield with mild and not hazardous applications. However, enzyme specificity, activity, plant origin and characteristics, ratio, and extraction conditions differ depending on the goal. As a result, researchers have gained interest in enzymes’ ability to cleave specific bonds of macroelements and release bioactive compounds by enhancing value and creating novel derivatives in plant extracts. The extract is enriched with reducing sugars, phenolic content, and peptides by disrupting lignocellulose and releasing compounds from the cell wall and cytosolic. Nonetheless, depolymerizing carbohydrates and using specific enzymes form and release various saccharides lengths. The latest studies show that oligosaccharides released and formed by enzymes have a high potential to be slowly digestible starches (SDS) and possibly be labeled as prebiotics. Additionally, they excel in new technological, organoleptic, and physicochemical properties. Released novel derivatives and phenolic compounds have a significant role in human and animal health and gut-microbiota interactions, affecting many metabolic pathways. The latest studies have contributed to enzyme-modified extracts and products used for functional, fermented products development and sustainable processes: in particular, nanocellulose, nanocrystals, nanoparticles green synthesis with drug delivery, wound healing, and antimicrobial properties. Even so, enzymes’ incorporation into processes has limitations and is regulated by national and international levels.     

Using Exogenous Melatonin,Glutathione, Proline,and Glycine Betaine Treatments to Combat Abiotic Stresses in Crops

Abiotic stresses, such as drought, salinity, heat, cold, and heavy metals, are associated with global climate change and hamper plant growth and development, affecting crop yields and quality. However, the negative effects of abiotic stresses can be mitigated through exogenous treatments using small biomolecules. For example, the foliar application of melatonin provides the following: it protects the photosynthetic apparatus; it increases the antioxidant defenses, osmoprotectant, and soluble sugar levels; it prevents tissue damage and reduces electrolyte leakage; it improves reactive oxygen species (ROS) scavenging; and it increases biomass, maintains the redox and ion homeostasis, and improves gaseous exchange. Glutathione spray upregulates the glyoxalase system, reduces methylglyoxal (MG) toxicity and oxidative stress, decreases hydrogen peroxide and malondialdehyde accumulation, improves the defense mechanisms, tissue repairs, and nitrogen fixation, and upregulates the phytochelatins. The exogenous application of proline enhances growth and other physiological characteristics, upregulates osmoprotection, protects the integrity of the plasma lemma, reduces lipid peroxidation, increases photosynthetic pigments, phenolic acids, flavonoids, and amino acids, and enhances stress tolerance, carbon fixation, and leaf nitrogen content. The foliar application of glycine betaine improves growth, upregulates osmoprotection and osmoregulation, increases relative water content, net photosynthetic rate, and catalase activity, decreases photorespiration, ion leakage, and lipid peroxidation, protects the oxygen-evolving complex, and prevents chlorosis. Chemical priming has various important advantages over transgenic technology as it is typically more affordable for farmers and safe for plants, people, and animals, while being considered environmentally acceptable. Chemical priming helps to improve the quality and quantity of the yield. This review summarizes and discusses how exogenous melatonin, glutathione, proline, and glycine betaine can help crops combat abiotic stresses.     

Effects of Extraction Temperature and Preservation Method on Functionality of Soy Protein

The effects of extraction temperature and preservation method on the functional properties of soy protein isolate (SPI) were determined. Four extraction temperatures (25, 40, 60, and 80 °C) were used to produce SPI and yields of solids and protein contents were determined. Three preservation methods were also tested (spray-drying, freeze-drying, and freezing–thawing) and compared to fresh (undried) samples for each extraction temperature. No differences in yields of solids and protein were observed among SPIs extracted at 25, 40, and 60 °C; however, SPI extracted at 80 °C yielded significantly less solids and protein. Extraction temperature significantly affected SPI functionality. As extraction temperature increased, solubility and emulsification capacity decreased; surface hydrophobicities, emulsification activities and stabilities, and dynamic viscosities increased; and foaming properties improved. Preservation method also significantly affected SPI functionality. Drying method did not affect the denaturation enthalpies of SPIs, but spray-dried SPIs had higher solubilities, surface hydrophobicities, and emulsification stabilities, and lower viscosities, emulsification activities and rates of foaming than freeze-dried SPI exhibited. Emulsification and foaming capacities and foaming stabilities were similar for both methods of drying. There was significant interaction between extraction temperature and preservation method for all functional properties except emulsification capacity.     

Mechanisms Governing Anaphylaxis: Inflammatory Cells,Mediators, Endothelial Gap Junctions and Beyond

Anaphylaxis is a severe, acute, life-threatening multisystem allergic reaction resulting from the release of a plethora of mediators from mast cells culminating in serious respiratory, cardiovascular and mucocutaneous manifestations that can be fatal. Medications, foods, latex, exercise, hormones (progesterone), and clonal mast cell disorders may be responsible. More recently, novel syndromes such as delayed reactions to red meat and hereditary alpha tryptasemia have been described. Anaphylaxis manifests as sudden onset urticaria, pruritus, flushing, erythema, angioedema (lips, tongue, airways, periphery), myocardial dysfunction (hypovolemia, distributive or mixed shock and arrhythmias), rhinitis, wheezing and stridor. Vomiting, diarrhea, scrotal edema, uterine cramps, vaginal bleeding, urinary incontinence, dizziness, seizures, confusion, and syncope may occur. The traditional (or classical) pathway is mediated via T cells, Th2 cytokines (such as IL-4 and 5), B cell production of IgE and subsequent crosslinking of the high affinity IgE receptor (FcεRI) on mast cells and basophils by IgE-antigen complexes, culminating in mast cell and basophil degranulation. Degranulation results in the release of preformed mediators (histamine, heparin, tryptase, chymase, carboxypeptidase, cathepsin G and tumor necrosis factor alpha (TNF-α), and of de novo synthesized ones such as lipid mediators (cysteinyl leukotrienes), platelet activating factor (PAF), cytokines and growth factors such as vascular endothelial growth factor (VEGF). Of these, histamine, tryptase, cathepsin G, TNF-α, LTC₄, PAF and VEGF can increase vascular permeability. Recent data suggest that mast cell-derived histamine and PAF can activate nitric oxide production from endothelium and set into motion a signaling cascade that leads to dilatation of blood vessels and dysfunction of the endothelial barrier. The latter, characterized by the opening of adherens junctions, leads to increased capillary permeability and fluid extravasation. These changes contribute to airway edema, hypovolemia, and distributive shock, with potentially fatal consequences. In this review, besides mechanisms (endotypes) underlying IgE-mediated anaphylaxis, we also provide a brief overview of IgG-, complement-, contact system-, cytokine- and mast cell-mediated reactions that can result in phenotypes resembling IgE-mediated anaphylaxis. Such classifications can lead the way to precision medicine approaches to the management of this complex disease.     

松香基表面活性剂研究进展

松香是一类产量丰富、价格低廉的可再生林产资源,被广泛地应用于食品、农业、橡胶、油墨、涂料等领域。松香的三环二萜结构具有超强的疏水性,通过催化异构、Diels-Alder加成等手段引入亲水基团可制备高附加值、易生物降解的绿色表面活性剂。本文从阴离子、阳离子、非离子和两性离子表面活性剂4个大类对松香基表面活性剂应用的文献及专利进行综述,重点分析了羧酸盐、磺酸盐、硫酸盐和磷酸盐4种阴离子型表面活性剂和季铵盐阳离子型表面活性剂,多元醇型和聚氧乙烯型非离子表面活性剂,以及甜菜碱型和氧化胺型两性离子表面活性剂。剖析松香基表面活性剂产业化开发的新技术及新产品概况,提出松香基表面活性剂替代传统表面活性剂的潜在应用领域。同时,对松香基表面活性剂的研究发展与产业化发展进行了评价与展望。     

Free primary alcohols in oils and waxes from germs,kernels and other components of nuts,seeds, fruits and cereals

The composition of free primary alcohols in oils and waxes obtained from the germ, kernel, seed coat, shell and skin (peel) of various nuts, seeds, fruits and cereals and from the chrysalis of silkworm was examined. These alcohols are usually present in small amounts, along with large quantities of hydrocarbons, esters and glycerides in oils and waxes. Thus, it is necessary to remove hydrocarbons, esters and glycerides to analyze the alcohols. We found that preparative reverse-phase thin-layer chromatography (TLC) was the best way to isolate alcohols from oils and waxes. Gas liquid chromatography (GLC) then detected hexacosanol, octacosanol and triacontanol in the oils and waxes. Octacosanol usually was the predominant alcohol. Relationships between the organs from nuts, seeds, fruits and cereals and the contents of octacosanol are suggested. For example, degermed kernels contained two times more octacosanol than the germ, and the skin coat and shell contained one-half and one-fortieth the octacosanol of the germ, respectively.     

Laccases and Tyrosinases in Organic Synthesis

Laccases (Lac) and tyrosinases (TYR) are mild oxidants with a great potential in research and industry. In this work, we review recent advances in their use in organic synthesis. We summarize recent examples of Lac-catalyzed oxidation, homocoupling and heterocoupling, and TYR-catalyzed ortho-hydroxylation of phenols. We highlight the combination of Lac and TYR with other enzymes or chemical catalysts. We also point out the biological and pharmaceutical potential of the products, such as dimers of piceid, lignols, isorhamnetin, rutin, caffeic acid, 4-hydroxychalcones, thiols, hybrid antibiotics, benzimidazoles, benzothiazoles, pyrimidine derivatives, hydroxytyrosols, alkylcatechols, halocatechols, or dihydrocaffeoyl esters, etc. These products include radical scavengers; antibacterial, antiviral, and antitumor compounds; and building blocks for bioactive compounds and drugs. We summarize the available enzyme sources and discuss the scalability of their use in organic synthesis. In conclusion, we assume that the intensive use of laccases and tyrosinases in organic synthesis will yield new bioactive compounds and, in the long-term, reduce the environmental impact of industrial organic chemistry.     

Recent Progress in Biopolymer-Based Hydrogel Materials for Biomedical Applications

Hydrogels from biopolymers are readily synthesized, can possess various characteristics for different applications, and have been widely used in biomedicine to help with patient treatments and outcomes. Polysaccharides, polypeptides, and nucleic acids can be produced into hydrogels, each for unique purposes depending on their qualities. Examples of polypeptide hydrogels include collagen, gelatin, and elastin, and polysaccharide hydrogels include alginate, cellulose, and glycosaminoglycan. Many different theories have been formulated to research hydrogels, which include Flory-Rehner theory, Rubber Elasticity Theory, and the calculation of porosity and pore size. All these theories take into consideration enthalpy, entropy, and other thermodynamic variables so that the structure and pore sizes of hydrogels can be formulated. Hydrogels can be fabricated in a straightforward process using a homogeneous mixture of different chemicals, depending on the intended purpose of the gel. Different types of hydrogels exist which include pH-sensitive gels, thermogels, electro-sensitive gels, and light-sensitive gels and each has its unique biomedical applications including structural capabilities, regenerative repair, or drug delivery. Major biopolymer-based hydrogels used for cell delivery include encapsulated skeletal muscle cells, osteochondral muscle cells, and stem cells being delivered to desired locations for tissue regeneration. Some examples of hydrogels used for drug and biomolecule delivery include insulin encapsulated hydrogels and hydrogels that encompass cancer drugs for desired controlled release. This review summarizes these newly developed biopolymer-based hydrogel materials that have been mainly made since 2015 and have shown to work and present more avenues for advanced medical applications.     

Organokines in Rheumatoid Arthritis: A Critical Review

Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily affects the joints. Organokines can produce beneficial or harmful effects in this condition. Among RA patients, organokines have been associated with increased inflammation and cartilage degradation due to augmented cytokines and metalloproteinases production, respectively. This study aimed to perform a review to investigate the role of adipokines, osteokines, myokines, and hepatokines on RA progression. PubMed, Embase, Google Scholar, and Cochrane were searched, and 18 studies were selected, comprising more than 17,000 RA patients. Changes in the pattern of organokines secretion were identified, and these could directly or indirectly contribute to aggravating RA, promoting articular alterations, and predicting the disease activity. In addition, organokines have been implicated in higher radiographic damage, immune dysregulation, and angiogenesis. These can also act as RA potent regulators of cells proliferation, differentiation, and apoptosis, controlling osteoclasts, chondrocytes, and fibroblasts as well as immune cells chemotaxis to RA sites. Although much is already known, much more is still unknown, principally about the roles of organokines in the occurrence of RA extra-articular manifestations.