Low Molecular Material Research Articles

Response of microbiomes with different abundances to removal of metal fractions by soil washing

Toxic metal contamination causes a great threat to soil ecosystem and human health. Soil washing is a fast practice for removing metals, but its influences on microbial diversity and the stability of soil ecosystem remain unknown. In this study, ethylenediaminetetraacetic acid (EDTA), citric acid (CA), and fermented pineapple peel residue (FPP) were used as representatives of chelates, low molecular organic acids and biological materials to wash Pb-polluted soils, and their impacts on microbial community were investigated. Washing with these agents effectively removed Pb, but altered microbial community structure. After washing with EDTA, CA, and FPP, 3–8 bacterial phyla and 1 fungal phylum greatly increased, while 7–20 bacterial and 0–6 fungal phyla severely decreased or even disappeared. The alterations of different microbiomes were closely related to soil metal fractions. The labile metal fraction had negative effects on most bacteria and fungi, but also showed positive influences on Actinobacteria, Patescibacteria, and Fusobacteria. The moderately stable and stable fractions were nontoxic to the most microbes, but still harmful to Patescibacteria and Deinococcus-Thermus. These findings provide new insights for the effects of soil washing remediation and toxicity of metal fractions on the microbiomes with different abundance.

Low molecular weight self-assembling peptide-based materials for cell culture, antimicrobial, anti-inflammatory, wound healing, anticancer, drug delivery, bioimaging and 3D bioprinting applications.

In this review, we have focused on the design and development of low molecular weight self-assembling peptide-based materials for various applications including cell proliferation, tissue engineering, antibacterial, antifungal, anti-inflammatory, anticancer, wound healing, drug delivery, bioimaging and 3D bioprinting. The first part of the review describes about stimuli and various noncovalent interactions, which are the key components of various self-assembly processes for the construction of organized structures. Subsequently, the chemical functionalization of the peptides has been discussed, which is required for the designing of self-assembling peptide-based soft materials. Various low molecular weight self-assembling peptides have been discussed to explain the important structural features for the construction of defined functional nanostructures. Finally, we have discussed various examples of low molecular weight self-assembling peptide-based materials for cell culture, antimicrobial, anti-inflammatory, anticancer, wound healing, drug delivery, bioimaging and 3D bioprinting applications.

Specific Features of Fluoroplastic Band Bending with Due Account of Various Modularity of Material

The paper considers a technological process for production of sealing rings by winding a band work-piece on a cylindrical caliber mandrel with subsequent endurance under load and further cutting of a spiral in rings and also studies the possibility to obtain products while using a method for cold forming of a work-piece which excludes thermal stabilization operation. Taking into account the fact that fluorine plastic is a high-plastic material even at very low temperatures such technology looks quite real. Therefore winding of a band on a mandrel, endurance of a spiral work-piece without heating but under conditions of force action within the time which is necessary for completion of relaxation processes, and the subsequent cutting in rings will allow to obtain finished ring products of the required size. However fluoroplastic has specific mechanical properties and a number of specific features which are revealed during deformation process. Its deformation behavior considerably differs from behavior of low-molecular materials and therefore it requires a solid approach while using the existing theoretical base and developing calculation methodologies. While taking into consideration the fact that fluorine plastic is high density material and has structure with high degree of crystallinity, the mechanism of deformation behavior in it under conditions of a force field is mainly similar to metal behavior that allows to use methods and approaches for calculation of fluoroplastic products which are accepted in mechanics of solid bodies. However the applied calculating formulae require a certain correction and adaptation to specific features of mechanical fluoroplastic properties, one of which is its various rigidity at stretching and compression that is revealed in case of winding band work-piece on a mandrel. Fluorine plastic is a material with various modularity and its rigidity is higher during compression than under stretching and consequently in the case of band bending a neutral axis of section is displaced from the center of gravity to the area of compressed fibers, and the area of stretching is increasing. High elasticity at stretching and increase of this area lead to large accumulation of elastic deformations causing springing after unloading and changes in size of a finished product. These facts must be taken into account while calculating and designing a mandrel tool, it is also necessary to keep in mind various modularity of a material and possibility that a section being led to an uniform rigidity may take some other shape due to this. Calculation methodologies have been developed by the authors for both versions of section that take into consideration directly or indirectly a material with various modularity and which do not contradict each other and which are rather precisely proved by experimental data.

Influence of Elastic Core on Size of Ring Product under Bending of Fluoroplastic Band

The paper is devoted to study of a possibility to manufacture fluoroplastic products while using method of cold deformation of pressed blanks and research of peculiar features in mechanical behavior of fluoroplastic which are revealed during deformation that affects quality and accuracy of the manufactured parts. Manufacturing technique of fluoroplastic sealing rings which are obtained while using method of coiling a band blank on a cylindrical mandrel with further endurance in a wound state and subsequent cutting of a spiral on rings has been considered in the paper. An important stage in the development of the technological process is a calculation and a design of a tool (mandrel caliber) that ensure obtaining of ring products with the required size and shape. Deformation behavior of fluoroplastic under conditions of force action is significantly different from the behavior of the known classical materials and it has a number of specific features and manifestations. Therefore the problem for creation of a calculation methodology for tool development looks as a complicated one and it requires a justified approach while selecting a mechanical model of polymer. Considering the fact that fluoroplastic has a structure with a high degree of crystallinity, a mechanism and sequence of deformations in it due to load are largely similar to the behavior of metals and other low-molecular materials. It allows to use methods and approaches adopted in the mechanics of solids for a calculation of fluoroplastic products however it is necessary to take into account the fact that deformation processes in polymers proceed in time and have a different nature of elastic and residual deformations. When bending the fluoroplastic band in case of winding it on the mandrel residual deformations which provide the required size and shape play the most significant role. However elastic deformations which cause springing and change of size in a finished product after removal of loading are also important. It has been proved that an elastic zone of finite width which has a certain influence on accuracy of manufactured products with due account of all accumulated elastic deformations will be present in the field of a neutral layer even at high degrees of deformation. In this case, fluoroplastic is a multi-modulus material having elasticity which at stretching is significantly higher than in compression, and therefore elastic recovery is more associated with the area of stretched fibers. The authors have developed a methodology for calculation of the tool for obtaining rings of the required size on the basis of the analysis pertaining to deformation behavior of the fluoroplastic while taking into account specificity of its mechanical properties. The proposed methodology with a sufficient degree of accuracy is consistent with the results of experimental studies.

New Methods of Lignin Processing into Organic Low Molecular Compounds and Nanoporous Materials

New Methods of Lignin Processing into Organic Low Molecular Compounds and Nanoporous Materials

Redox-sensitive reversible self-assembly of amino acid-naphthalene diimide conjugates.

Peptide and low molecular weight amino acid-based materials that self-assemble in response to environmental triggers are highly desirable candidates in forming functional materials with tunable biophysical properties. In this paper, we explore redox-sensitive self-assembly of cationic phenylalanine derivatives conjugated to naphthalene diimide (NDI). Self-assembly of the cationic Phe-NDI conjugates into nanofibrils was induced in aqueous solvent at high ionic strength. Under reducing conditions, these self-assembled Phe-NDI conjugate fibrils underwent a morphological change to non-fibril aggregates. Upon reoxidation, the initially observed fibrils were reformed. The study herein provides an interesting strategy to effect reversible switching of the structure of supramolecular materials that can be applied to the development of sophisticated stimulus-responsive materials.

On the relaxation nature of the glass transition of amorphous polymers and low-molecular amorphous materials

The relative temperature range (δTg/Tg) characterizing the liquid-to-glass transition is a single-valued function of the fluctuation volume fraction fg frozen at the glass transition temperature Tg. The fluctuation volume ΔVe of the amorphous material is determined by delocalization of active (excited)) atoms, i.e., their thermal displacements from equilibrium positions. The fluctuation volume fraction f = ΔVe/V controls the molecular mobility that is characteristic of delocalized atoms in the liquid-glass transition region. It is shown that δTg for the majority of amorphous materials is only 0.7% of the glass transition temperature Tg. The narrow temperature range δTg is consistent with the classical Simon concept on the insignificant temperature range in which the structure is frozen.

Zinc titanate nanopowder: an advanced nanotechnology based recyclable heterogeneous catalyst for the one-pot selective synthesis of self-aggregated low-molecular mass acceptor–donor–acceptor–acceptor systems and acceptor–donor–acceptor triads

Highly stable, environmentally benign ZnTiO3 nanopowder has been prepared via a sustainable sol–gel method. The nanopowder (90 nm) has been thoroughly characterized by SEM, XRD, EDS, Laser Raman, photoluminescence, UV and IR. The activity of the catalyst was probed through one-pot four-component reaction of aldehydes, ketones and two equivalent propanedinitriles in water without requiring any additives or anhydrous conditions. The reaction requires two different catalytic functions, i.e., an acidic one which is given by Ti(IV) ions and a basic one, given by the oxide ion incorporated within the ZnTiO3 metal oxide framework. The advantages of this method lie in its simplicity, cost effectiveness, environmental friendliness, and easier scaling up for large scale synthesis without using high pressure, temperature and toxic chemicals. As water was used as a reaction medium and since we are particularly interested in the isolation of a non-aromatic intermediate, the elimination of poisonous HCN was prevented by the Lewis acid character of Ti4+ up to a sufficiently high temperature. Thus, this process can be considered as a “green” process. Elimination of HCN at higher temperatures still maintains “green” attributes as HCN can be trapped by the basic catalyst under such conditions. Spontaneous generation of low molecular mass self-aggregated organic materials, their one-dimensional packing, and interesting photophysical properties are reported.

Synthesis of Glycal-Based Chiral Benzimidazoles by VO(acac)2−CeCl3 Combo Catalyst and Their Self-Aggregated Nanostructured Materials

VO(acac)(2)-CeCl(3) combo catalyst has been developed for chemoselective cyclocondensation cum oxidation under mild reaction conditions toward synthesis of a new class of optically pure compounds, 2-(2'-C-3',4',6'-tri-O-benzyl/methyl-glycal)-1H-benzimidazoles. It involves an operationally simple synthetic protocol efficient for the syntheses of a wide range of chiral benzimidazoles in high yields without formation of undesired 1,2-disubstituted and pseudoglycal byproducts. Vanadium(V) is found as active oxidant for the chemical processes which is investigated by UV absorption spectroscopy. Highly ordered one-dimensional low molecular mass organic nanostructured materials are fabricated by nanocrystallization of the chiral nanoscale building blocks. Theoretical calculation by the B3LYP/6-31G** level of theory of the glycal-based chiral benzimidazoles shows out of planar geometry of the 1H-anthra[1,2-d]imidazole-6,11-dione moiety, which is responsible for the strong self-aggregation to generate ultralong nanostructured materials. We have also found nice agreement between the theoretical results with the experimental observation in 2D-NOESY experiments. The photophysical property of the solid nanostructured materials is also reported.

Structures of the cylindrical and vesicular micelles of an P4VP-longer asymmetric PS-b-P4VP

The control of the self-assembled micellar morphology of amphiphilic block copolymers in a selective solvent has engrossed substantial interests in the theoretical and applied research fields. The micellar morphology of the block copolymers can be controlled by solvent selectivity and block copolymer composition. There are three main factors for controlling these morphologies, i.e., the stretching of core blocks, the repulsive interaction among corona chains, and the surface tension of the core/corona interface at the onset of micellization. The block copolymer can selfassemble into spherical, cylindrical, and vesicular micelles in a given solution. Among those micelles, the vesicle has fascinated scientists because of its diverse applications such as drug delivery diagnostics, electronics (chip nanopatterning), and catalysis (enzyme entrapment). Vesicles (generally kinetically trapped and non-equilibrium) are usually formed by low molecular materials such as surfactants or lipids. Wittmann et al. for the first time reported the polymeric vesicles of poly(styrene-b-isoprene) (PS-b-PI) and poly(styrene-b-ethylene oxide) (PS-b-PEO) in a mixture of ethyl benzene (a selective solvent for both blocks) and n-decane (a PI and PEO selective solvent). Schrage et al. investigated vesicular morphologies of quaternized poly(1-methyl-4vinyl pyridine-b-styrene) and poly(1,2-butadiene-b-(cesium methacrylate)) which were self-assembled in THF (nonselective for PS and poly(1,2-butadiene) but selective for charged blocks). Kesselman et al. also studied the change in the vesicular morphologies of PS-b-PI by controlling solvent selectivity in diethyl phthalate (less PS-selective) and dimethyl phthalate (highly PS-selective) mixtures. Putaux et al. investigated the vesicular morphologies of PS-b-PI in n-heptane and n-decane, both of which are selective solvents for PI. The PS-b-P4VP vesicles have been observed when the P4VP blocks were complexed with other small molecules. The vesicles of PS-b-P4VP in chloroform were observed when perfluorooctanoic acid (PFOA) was added to be complexed with P4VP. Peng et al. also reported another interesting research on the vesicular morphology of PS-b-P4VP in a complex form with low molecular-weight aliphatic acids (stearic acid, decanoate, acetic acid, and formic acid) in chloroform (non-selective for PS-b-P4VP and aliphatic acids but selective in a complex form). But, PS-bP4VP vesicles without complexation were rarely observed. The cylindrical morphology of an asymmetric PS(19600)b-P4VP(5100) (PS longer) in P4VP selective solvents was reported. However, the vesicles with asymmetric PS-b-P4VPs (P4VP longer) in PS selective solvents have not been reported. The block length of P4VP of the PS-b-P4VP is of prime importance because a number of valuable metals or small molecules could be complexed with the P4VP core of micelles (in the PS selective solvents) which is utilized as a nanoreactor. The screening of the solvent selectivity is necessary to check the possible micellar morphologies of the given block copolymer. Recently the micellar structures and their ordered structures of PS(12K)-b-P4VP(11.8K) and PS(19.6K)-b-P4VP (5.1 K) in the toluene/ethanol solvent system were reported. However, we believe that solvent selection for PS-b-P4VP is important in this study. We used the toluene/ethanol solvent system where toluene and ethanol are selective solvents for PS and P4VP, respectively. The toluene/ethanol system covers from PS-selective, to neutral, and to P4VPselective solvents although our previous THF/toluene system covers only from neutral to PS-selective solvents. Thus, we expected that a wider range of the micellar morphologies can be formed in the toluene/ethanol solvent system. The solvent selectivity was narrowly screened by changing the mixing ratio of the two solvents. But the vesicular structure was not found probably due to the less-asymmetric composition of the block copolymer and/or the less selectivity of the used solvent mixtures. The research in this article used a more-asymmetric block copolymer of PS (3.3K)-b-P4VP(18.7 K) (P4VP longer) in the toluene/ethanol mixtures to screen the solvent selectivity.

PhIO as a Powerful Cyclizing Reagent: Regiospecific [3+2]-Tandem Oxidative Cyclization of Imine toward Cofacially Self-Aggregated Low Molecular Mass Organic Materials

The powerful cyclization and tandem oxidation property of environmentally benign PhIO is developed for the first time, which leads to regiospecific [3+2]-tandem oxidative cyclization of imine at room temperature in rapid access to a new class of compounds, 1,2-functionalized 4,5-diarylimidazoles, in excellent yield with synthetic efficiency. Size, shape, and activity of the involved nanoreactors for the green approach built up from various surfactants are investigated. Spontaneous generation of low molecular mass self-aggregated organic materials, their cofacial one-dimensional packing, and interesting photophysical properties are reported.

HPLC를 이용한 어패류 중의 테트라사이클린계 항생제 분석방법 개발

An analysis method of tetracyclines far fish and shellfish products containing large amount of low molecular materials and pigments was established. The recovery of the established analysis method for four tetracycline samples was <TEX>$72-100\%$</TEX> and higher than other methods reported. Especially, proposed sample treatment protocol was shown to be effective for the removal of low molecular materials and pigments that tend to interfere with accurate analysis. The detection limit of oxytetracycline (OTC) and tetracycline (TC) from the sample was 0.02 ppm, and the detection limit of chlortetracycline (CTC) and doxycycline (DC) from the sample was 0.1ppm, To examine the efficiency of the established method and identify tetracycline usage in fish farms, tetracycline group antibiotics in the flounder being cultured was monitored. The improved method can be used for fish and shellfish products effectively and all surveyed fish farms have used tetracycline all the year round. The proposed method was adopted as official method for fishery products by Korean Food and Drug Administration in 2003 and it is being used by regulatory authority as National Fishery Products Quality Inspection Service.

Production of colloidally stable latices from low molecular weight ethylene–propylene–diene copolymers

The best impact modifiers for coatings and engineering plastics include fixed morphology core-shell particles. For the present work, ethylene–propylene copolymers (EPM) and ethylene–propylene–diene copolymers (EPDM) were chosen, for their good resistance to stringent conditions, like UV-irradiation or high temperatures, to prepare the core of the desired particles. The solution-emulsification technique was used to produce artificial latices based on low molecular weight EPM and EPDM materials. Conventional emulsification techniques as well as ‘miniemulsification’ methods have been investigated. In both cases, a larger volume of polymer is reduced into smaller sub-units using the mechanical energy of comminution techniques, i.e. an Ultra-Turrax ® and a homogenizer operating at a pressure of 300 bar and with a shear rate of approximately 3.2×10 7 s −1. The difference between conventional emulsification and miniemulsification resides in the stabilizing system. For the conventional emulsification method, an equimolar mixture of anionic (sodium dodecyl benzene sulfonate, SDBS) and nonionic (polyoxyethylene (100) stearyl ether, Brij 700) surfactants was found to be the optimal surfactant system. For the miniemulsification method, a combination of SDBS as surfactant and hexadecane or cetyl alcohol as costabilizer was the most suitable system. Both conventional emulsification and miniemulsification lead to latices with monomodal particle size distributions and volume-average diameters ranging from 300 to 400 nm, determined with light scattering techniques. The low molecular weight elastomers, exhibiting viscosities lower than 1 Pa s at 20 °C, were easily emulsified without addition of organic solvent.

Acetylation of wheat straw using simplified procedure and ultrasonic irradiation

AbstractAn investigation of the acetylation of wheat straw with acetic anhydride using a simplified procedure and with or without ultrasonic irradiation was undertaken. The new procedure greatly shortened the reaction time and simplified the chemical recovery. Acetylation weight gains of 15.8% can be achieved in 1 h at 120°C without ultrasound assistance. At the same reaction conditions but with ultrasound assistance at 60°C for 5 min, a weight percent gain (WPG) value of 15.0% was obtained, indicating a slightly negative effect of ultrasonic irradiation on the rate of acetylation without solvents or catalysts. However, a positive sonication effect on the solubility of low molecular materials, mainly extractives, was found in all the cases of the reactions. The characterization of acetylated wheat straw was performed by FTIR, solid‐state 13C‐NMR, and thermal studies, which provided evidence for acetylation. The thermal stability of acetylated straw was found to be higher than that of unmodified wheat straw. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1277–1284, 2003

P‐88: Low Driving Voltage of Cholesteric Liquid Crystal Displays

AbstractA high‐resolution 5.7″ VGA mono cholesteric reflective liquid crystal display was demonstrated using a STN driver. We have reduced the driving voltage of Ch‐LCD by optimizing panel conditions and adding low molecular materials. The optimized driving voltage was enough to drive the display, necessary for using a commercial STN driver.

Nematic order and nuclear magnetic relaxation in PCH-3 liquid crystal

Proton NMR was employed to study the nematic phases upon heating and upon cooling in PCH-3 (trans-4 (4-propylcyclohexy) benzonitrile). Our systematic measurements of the nematic order parameter and spin relaxations reveal the microscopic nature of the thermal hysteresis in this relatively low molecular weight nematic liquid crystalline material. 2001 Published by Elsevier Science B.V.

Serum Cholesterol-lowering Effect of Fermented Milk with Streptococcus thermophilus TMC 1543

The serum cholesterol lowering action of fermented milk with Streptococcus thermophilus TMC 1543 (1543FM), the mechanism behind the cholesterol lowering activity and the active factor in animal experiments were investigated using rats. The serum total cholesterol level of the group fed 1543FM was significantly lower than that of the control group (P<0.05). However, there were no serum cholesterol lowering activities in fermented milks with the other two lactic acid bacteria. The serum total cholesterol concentration of the group fed low-molecular-weight fraction (LMF) from 1543 FM was significantly lower than that of the control group (P<0.05). High-molecular-weight fraction (HMF) also tended to lower serum cholesterol level in the present animal study. The amounts of excretion of both total bile acid and neutral sterol in feces of the 1543FM group increased significantly in comparison with the control group (P<0.05). These results suggest that the mechanism behind serum cholesterol lowering activity of 1543FM would be attributable to the promotion of excretion of bile acid and neutral steroid through feces, and probably the low-molecular material in LMF.

Uber die Isolierung von Sitosterin-(6'-O-acyl)-β-D-glucopyranosiden aus Flacourtia indica und über unerwartete Gelbildungen durch das Triacetat / On the Isolation of Sitosterin-(6'-O-acyl)-β-D-glucopyranosides from Flacourtia indica and on Unexpected Formation of Gels by the Triacetate

Abstract A mixture of the title compound-(6′) stearate, margarate, palmitate, linolate, and linole- nate (2a-e) was isolated from shredded dried leaves and twigs of Flacourtia indica. The margarate was observed for the first time. 0.5% solutions of the triacetate mixture (1a-e) in methanol or ethanol give “solid" gels stable for months. From these the unchanged triacetates 1a-e can be recovered indicating that this low-molecular material is responsible for the formation of the gel.

Electroluminescent behaviours of polymer/organic heterostructure devices

Polymer/organic heterostructure electroluminescent devices were fabricated with poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) for emissive polymer layer and various organic materials such as tris(8-hydroxyquinoline) aluminum (Alq3), rubrene (Rub), quinacridone (Qc) and 2-(4′-biphenyl)-5-(4″-tert-butylphenyl)-1,3,4-oxadiazole (PBD) for hole blocking layer. All kinds of organic low molecular materials in this study show hole blocking property, but electroluminescence (EL) characteristics of some structures were not distinctly enhanced because of re-absorption by organic materials, their poor film quality, low electron mobility. The ITO/MEH-PPV/Alq3/Al structured device shows the highest luminescence among the organic molecules used in this study at low current less than about 3 mA.

Haemocyanin and the binding of cadmium and zinc in the haemolymph of the shore crab Carcinus maenas (L.)

The trace metals cadmium and zinc are taken up from solution into haemolymph of the shore crab, Carcinus maenas, where they bind to the respiratory pigment haemocyanin. Investigations using FPLC and PAGE to separate the constituent dodecamer and hexamer aggregations of haemocyanin showed a difference between the distribution of cadmium and zinc between the two aggregate states. In the haemolymph, labelled cadmium binds not only to haemocyanin but, at least initially, it is also associated with low molecular size material or exists as free cadmium ions. The binding of cadmium to haemocyanin is not an immediate process. Initially the binding of cadmium favours the hexamer; only later is a more even distribution between the two aggregate states apparent. Newly taken up labelled zinc is rapidly bound to haemocyanin. The majority of both total and labelled zinc in the haemolymph is bound to haemocyanin, with the hexamer having a greater binding affinity for zinc than the dodecamer. This suggests that formation of the dodecamer leads to a blocking of zinc-binding sites and/or that the hexamer consists of subunits which possess a relatively high affinity for zinc.