Micellar and Interfacial Behavior of Cationic Benzalkonium Chloride and Nonionic Polyoxyethylene Alkyl Ether Based Mixed Surfactant Systems

Micellar and interfacial properties of mixed surfactant systems comprising benzalkonium chloride, a cationic surfactant and nonionic polyoxyethylene alkyl ether surfactants (POE: C₁₀E₇, C₁₀E₈, C₁₀E₉, C₁₀E₁₀) have been investigated by surface tension, fluorescence and dynamic light scattering techniques. Critical micelle concentration (CMC) for different mixing mole fractions has been investigated by surface tension and fluorescence measurements. Ideal CMC, mixed micellar composition (X ₁ ^m , X ₁ ^σ ), interaction parameters for mixed micelles (β ^m) and adsorption monolayer (β ^σ ), surface excess concentration (Г_max), minimum area per molecule (A _min) and related thermodynamic properties have also been determined. Lowering of the CMC and negative interaction parameter values indicate synergism in the mixed micelle and monolayer formed, whereas, thermodynamic parameters evaluated for the proposed mixed systems indicate stability of the resulting micelles and monolayer. Micellar aggregation number (N _agg) and hydrodynamic diameter (D _h) computed from fluorescence and dynamic light scattering measurements respectively illustrate micellar growth in the mixed state. Results obtained for the proposed mixed systems can be helpful in designing smart materials for industrial surfactant based formulations.     

结核分支杆菌对抗痨药物组合依赖的初步调查

目的调查结核分支杆菌对抗痨多药组合的依赖情况。方法用双向匡氏琼脂培养基对184例结核杆菌阳性菌株进行多药组合HR、HRS、HRE依赖性实验。结果HR、HRS、HRE组合的依赖率分别为13．04％（24／184）,9．78％（18／1841,7．07％（13／184）。对HR组合依赖的24株菌株中,依赖R的占75％（17／24）,依赖H的占50％（12／24）,依赖H和R的占29．17％（7／24）,不依赖H和R的占4．17％（1／24）;对HRS组合依赖的18株菌中,依赖R的占94．44％（17／18）,依赖H的占44．44％（8／18）,依赖S的占38．89％（7／18）,同时依赖H、R、s的占16．67％（3／18）,均不依赖的占5．56％（1／18）,对HRE组合依赖的13株菌中,依赖R的占92．31％（12／13）,依赖H的占46．15％（6／13）,依赖E的占76．92％（10／13）,三者同时依赖的占30．77％（4／13）,三者均不依赖的未见。结论结核分支杆菌对多药组合HR、HRS、HRE具有不同程度的依赖现象,对三种药物组合依赖的菌株对R的依赖率最高。     

Review of synergistic photo-thermo-catalysis: Mechanisms,materials and applications

Solar energy is potentially the most promising type of renewable energy for large-scale utilization in the future, thus maximizing the use of solar energy has long been long pursued. Photo-thermo-catalysis (PTC) has presented a novel strategy that could utilize the full-spectrum sunlight to stimulate the synergy between photocatalysis (PC) and thermocatalysis (TC), which not only achieves high utilization efficiency of solar energy but also minimizes the energy consumption compared to sole PC and TC. This review strives to give a comprehensive overview of major advances of PTC. It starts with the fundamental mechanisms of PTC categorized by either heating mode (local and global) or photo-thermal synergic mode (thermal-assisted photocatalysis, photo-assisted thermocatalysis, photo-driven thermocatalysis and photo-thermal co-catalysis). Then, various photo-thermal materials are illustrated, including metals, semiconductors, carbon materials, etc. After that, we focus on the diverse applications of PTC, specifically in the fields of energy (CO₂ reduction and H₂ evolution), environment (VOCs and 4-NP degradations) and organic synthesis (Suzuki coupling and cyclocondensation reactions). Special emphasis is placed on the synergism of photo and thermal effect that leads to enhanced catalytic performances in PTC. Finally, the challenges and perspectives of PTC are discussed. We hope this review could shed some light on the fundamental mechanisms of PTC reactions and serve as a clearer guidance for synergistically high-efficient solar energy utilization systems in the future.     

Reactive Modification of Thermoplastic and Thermoset Polymers using Flame Retardants: An Overview

Flame retardants are the chemicals used in thermoplastics, thermosets, textiles and coatings to arrest the spread of fire. There are basically two methods to improve flame retardancy, namely additive and reactive. It was observed that the reactive modification enhances flame retardancy of polymer to the greater extent than the additive route. Hence in this review, more emphasis is given to the reactive approach. The following review depicts various flame retardants that can be incorporated to thermoplastic and thermosetting polymers, their mechanism of action and their combined effect on flame retardant properties of a polymer system in which they are incorporated in.     

Efficacy of a combination of nisin and p-Anisaldehyde against Listeria monocytogenes

Nisin is used as a food-safe antimicrobial agent and has been widely applied to daily food products to prevent bacterial growth. However, the practical application of nisin is limited. Although nisin inhibits the growth of Listeria monocytogenes, exposure to this agent is also a risk factor for the development of nisin resistance. p-Anisaldehyde (AS) is used in the pharmaceutical industry to manufacture antimicrobial drugs, but few studies have been reported describing the antibacterial activity of AS in the food field. Combining nisin with AS may enhance antimicrobial activity. The synergy observed in vitro was confirmed by checkerboard microdilution method, with the fractional inhibitory concentration index (FICI) values ranging from 0.125 to 0.281. When AS was combined with nisin, a strong synergistic effect was observed using the time-kill and agar-diffusion assays. SEM and LIVE/DEAD BacLight experiment results also suggest that the bactericidal mechanism of the drug combination involves cell wall lysis and membrane damage. We can use this synergy to achieve a stable antimicrobial effect to overcome antimicrobial drug resistance.     

■酸酯类对食用油脂的抗氧化活性研究

本文考查了酸酯类在食用油脂中的抗氧化活性及与其它物质的协同增效作用，结果表明，酸辛酯具有良好的抗猪油氧化活性，而酸十二烷醇酯则在花生油中具有较强的抗氧化性能，二者都可以被柠檬酸增效，此外还初步试验了一种新的复合型食品添加剂的性能。     

魔芋水晶软糖生产工艺研究

提出以魔芋精及鹿角菜胶、汉生胶酸生产水晶软糖的方法。由于复酸胶中分子间的协同增效作用，使得凝胶软糖的制备更为方便、廉价。     

Efficacy and cytotoxic potential of deltamethrin,essential oils of Cymbopogon citratus and Cinnamonum camphora and their synergistic combinations against stored product pest,Trogoderma granarium (Everts)

Residual film method was followed to analyze the toxicity of deltamethrin, essential oils (EOs) of Cymbopogon citratus and Cinnamonum camphora in separate and form of various combinations against LHR1 and LHR2 populations of fifth instar larvae of Trogoderma granarium. The cytotoxic potential of LC_50s of both EOs, deltamethrin and their various combinations was as well investigated. The LHR2 population showed 23.73 fold deltamethrin resistance with respect to LHR1 population. Both EOs had high insecticidal activity than deltamethrin but C. citratus EO was less toxic than C. camphora EO against both populations. Based on strength of synergism and dose reduction index, the order of insecticidal activity of combinations in LHR1 population was: C. citratus EO: deltamethrin < C. camphora EO: deltamethrin < C. citratus EO: C. camphora EO < C. citratus EO: C. camphora EO: deltamethrin. In LHR2 population the order was: C. citratus EO: C. camphora EO < C. citratus EO: deltamethrin < C. camphora EO: deltamethrin < C. citratus EO: C. camphora EO: deltamethrin. Following to exposure of LC₅₀ of each treatment various markers of cytotoxicity viz., haemocyte viability, cell proliferation rate and mitochondrial dehydrogenase activity were decreased significantly with respect to control in both populations. Except for deltamethrin, each treatment significantly increased the lactate dehydrogenase activity. Phenoloxidase activity was reduced significantly in LHR1 population following to exposure of each treatment. Likewise, LHR2 population also showed significantly reduced activity of phenoloxidase following to exposure of each treatment except deltamethrin as it increased the activity. Furthermore, each marker of cytotoxicity was fluctuated in relation to the toxicity of LC₅₀ of treatments and combination contained both EOs and deltamethrin produced highest cytotoxicity. Findings of this study should be used in granaries for the effective control of insecticide resistance in T. granarium¹.     

Interaction of a Novel Anionic Gemini Surfactant Containing a Triazine Ring with Cetyltrimethylammonium Bromide in Aqueous Solution

The interaction between a novel anionic gemini surfactant containing a triazine ring, denoted as C8‐G, and cetyltrimethylammonium bromide (CTAB) has been investigated in aqueous solution. The surface tension vs log. molar concentration plots of the individual surfactants and their mixtures were measured at different temperatures (298, 303, 308, and 313 K) by the drop volume method. The surface properties and the interaction parameters of the adsorption monolayer and the mixed micelle were obtained from the plot. The results showed that the CMC of the C8‐G/CTAB mixture reached a minimum value of 3.20 × 10^?5 mol/L when α_G (the mole fraction of C8‐G in the mixed system) was 0.7 at 308 K, and the minimum γ_CMC was 28.1 mN/m obtained for the molar ratio of 0.9 at 308 K. Interaction between the two components was strongest () when α_G was 0.7 at 303 K. All the C8‐G/CTAB mixtures exhibited synergism in both surface tension reduction efficiency and mixed micelle formation except when the mole fraction of C8‐G (α_G) was 0.1, 0.5 and 0.9 at 313 K, and became greatest for the molar ratio of 0.7 at 303 K. The C8‐G/CTAB mixtures exhibited synergism in surface tension reduction effectiveness for all the complex ratios at 303 K, α_G = 0.1, 0.3, 0.9 at 308 K and α_G = 0.7 at 313 K, whereas the other surfactant mixtures did not show this synergism.     

Ecotoxicological Assessment of Mixtures of Ether Carboxylic Derivative and Amine-Oxide-Based Non-ionic Surfactants on the Aquatic Environment

The purpose of this study was to discuss the effect of the chemical structure of anionic and non-ionic surfactants and surface activity on toxicity. Single and binary mixtures of three ether carboxylic derivative surfactants and three amine-oxide-based non-ionic surfactants were used. Toxicity was determined using three test organisms: freshwater crustaceans (Daphnia magna), luminescent bacteria (Vibrio fischeri), and microalgae (Selenastrum capricornutum). The toxicity of surfactants is related to the hydrophobic alkyl chain, the degree of ethoxylation, and the critical micelle concentration of surfactants. Relationships found agreed with the fact that the lower toxicity is shown by the shorter alkyl chain. There is a strong relation between surface activity and toxicity: the toxicity increased as the CMC of the surfactant or mixtures of surfactants decreased. Commercial products are formulated using surfactants mixtures, so it is important to know their behavior using an easily measured property: the least toxic mixtures were formed by the surfactants having lower individual toxicity. Around the CMC, our data show a synergism for the binary mixtures. The results have given rise to a classification of the different surfactants and their mixtures according to the organism test, as safe, harmful or toxic. V. fischeri was in general the most sensitive microorganism to the toxic effect of the surfactants, followed by Daphnia magna, while Selenastrum capricornutum was more tolerant. These results can be useful for selecting technically efficient surfactants and their mixtures with a lower ecotoxicity on the aquatic environment.