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The prevalence of Clostridium difficile (CD) infection has grown rapidly due to resistance and the emergence of new, highly virulent strains of the organism that have become less sensitive to many antibiotics. Vancomycin and metronidazole are front-line treatments of CD infection that still show good efficacy, but their effectiveness has declined for the treatment of recurrent infection and less sensitive strains of CD. More recently, the macrolide antibiotic fidaxomicin been introduced in the treatment of CD infection. Its high cost and limited usefulness against recurrent infection has prompted the search for new, narrow spectrum agents. We identified the CD dihydroorotate dehydrogenase (DHODase) as a potential enzyme target for the design of Knoevenagel products formed from reaction of 2-thiobarbituric acid and naphthaldehyde substrates. The presence of a hydroxyl substituent at position C2 in the naphthaldehyde ring offers the possibility to form the Knoevenagel product and to cyclize to give the tetracyclic, oxadeazaflavine with benzo-homologation. In this work, the selectivity for straight-chain formation over competing cyclisation on Knoevenagel condensation between thiobarbituric acid and naphthaldehyde substrates was examined. The outcomes of uncatalyzed condensations in refluxing ethanol were investigated by various methods including high field 1H and 13C NMR. Unsubstituted naphthaldehyde and its 2-methoxyl derivative favored straight-chain product formation whereas use of 2-hydroxynaphthaldehyde favored cyclisation and concomitant Michael addition of a second molecule of the corresponding acid to the newly formed exocyclic C=C bond. The pattern of reactivity was mirrored in the benzaldehyde series where the presence of the 2-hydroxyl function led to cyclized products with concomitant formation of the Michael adducts. The Knoevenagel products and the benzo-homologated oxadeazaflavine derivatives are candidates for evaluation as potential growth inhibitors of CD.

Highly branched alkanes exhibit enhanced free volume relative to their straight chain analogues, leading to the increased solubility of sparingly soluble gases, such as N2, as well as lower hydroca...

Vancomycin is widely used for treatment of infection caused by methicillin-resistant Staphylococcus aureus (MRSA) leading to an increasing appearance of low-level vancomycin-resistant isolates called heterogeneous vancomycin-intermediate S. aureus (hVISA). The mechanism of vancomycin tolerance in hVISA is still unclear. This study aimed to investigate the fatty acid compositions of S. aureus isolates under the stress environment with vancomycin. The different responses of hVISA and vancomycin-susceptible S. aureus (VSSA) may lead to more understanding the mechanism. The bacterial lipid profiles were tested three times from three extractions of each isolate cultured on tryptic soy agar (TSA) and TSA with vancomycin. Of the 30 MRSA isolates studied, 13, 12, and 5 isolates were VSSA, hVISA, and VISA, respectively. The analysis of bacterial lipid profiles showed that under vancomycin stress, there was a reduction of straight chain fatty acids (SCFAs) in VSSA isolates but an increase in branched chain fatty acids (BCFAs). In contrast, the hVISA group exhibited an increase only in the BCFAs but not in SCFAs. Of interest, vancomycin had no effect on either BCFAs or SCFAs of the VISA cells. This study provided information of bacterial adaptation during stress with vancomycin that may be helpful to overcome the resistant bacteria.

NMR spectroscopy was used to measure hydrocarbon chain branching variability in meibum with age, gender and Meibomian gland dysfuction (MGD). A cohort of 65 meibum donors without dry eye and 31 donors with MGD was studied. Heteronuclear 2D NMR was used to confirm CH3 resonance assignments allowing us to positively identify 23 of the 27 proton resonances of cholesteryl ester and 1H resonances due to straight chain, iso-branched and anteiso-branched hydrocarbons. Meibum from donors without dry eye contained 57 ± 1% straight-chains, 23 ± 1% iso-branched chains and 20 ± 1% anteiso-branched hydrocarbon chains. Compared with meibum from donors without dry eye, meibum from donors with MGD contained less, 50 ± 2% straight-chains, more, 32 ± 2% iso-branched chains and the same amount, 18.0 ± 0.07%, of anteiso-branched hydrocarbon chains. Meibum hydrocarbon chain branching did not change with age between 22 and 68 years of age, nor was it influenced by gender. Based on previous studies, one would expect anteiso-branched chains would contribute to lowering the phase transition temperature of meibum, decrease the elasticity of the tear film lipid layer and increase the molecular area and spreading of meibum on the surface of the eye. Although we speculate that the observed differences in iso-chain branching do not influence tear film stability or rheology, the speculation has yet to be tested.

Soil water repellency affects vast regions of agricultural and native land across the globe. Sandy soils are most likely to develop non-wetting characteristics with susceptibility decreasing with clay content. This study uses molecular dynamics simulations combined with laboratory scale experiments to study the interactions and assembly of saturated C16 straight chain alcohol and carboxylic acid molecules on a range of soil surfaces. The development of severe water repellency on sand at low loading levels of palmitic acid (0.75 × 10−6 mol g−1) is explained in terms of favourable H-bonding with silica surfaces and the development of 2–3 layers of lateral aligned organic molecules on the mineral surface. The efficacy of kaolinite in lowering soil water repellency is attributed to the higher surface area of this mineral and favourable surface chemistry, which hinders formation of persistent organic multilayers.

Chemical compounds that comprise of atoms and bonds are conceptualized as graphs shaped by edges and vertices with the help of graph theory and topological indices. The purpose of topological indices is to serve as a tool that can relate the compound’s chemical structure with its physical and chemical properties. We have chosen the M-polynomial technique to compute the indices. In this paper, we have derived the M-polynomial for straight chain pentagons, alternate chain pentagons and double-row penta-chains and proved the same with mathematical induction. We have further obtained various vertex degree-based topological indices using the M-polynomial.

Research shows that the viscosity greatly reduction of viscous crude oil can improve the exploitation and promote the fluidity. We studied the effects and the mechanism of viscosity reduction of vi...

The hydrocarbon pattern in the floral scent of Yucca species was found to comprise a group of unbranched, mid-chain alkanes, alkenes, and an alkadiene. In Y. reverchonii, highly dominant (Z)-8-heptadecene is accompanied by (6Z,9Z)-6,9-heptadecadiene and heptadecane as minor components and by traces of other saturated and unsaturated hydrocarbons with similar chain length. Some of these volatiles proved to be perceived by the antennae of Tegeticula cassandra (pollinating seed-eater of Yucca) and Prodoxus decipiens (herbivore on Yucca). The possible biosynthesis of the compounds is discussed.

Summary We demonstrate new C38 and C39 found in Lake Van and Lake Fryxell are methyl-branched alkenones (brC38Me and brC39Et). Previous assignments of these compounds as straight chain C38Me and C39Et were incorrect. Double bond positions, determined based on mass spectra of corresponding DMDS adducts, are Δ 4, Δ 7, Δ 14, Δ 21 and Δ 28 for penta-unsaturated branched alkenones. Based on published DNA data and changes of branched alkenone percentages of Lake Van, we hypothesize that branched alkenones function as storage of energy and are produced by a yet unknown species of Isochrysidales. UKbr38Me based on brC38Me alkenones has a similar trend with UK37 in the past 270 ka of Lake Van, suggesting the high temperature sensitivity of branched alkenones, same as other straight chain alkenones. Such proxies based on branched alkenones might be more reliable than UK37 and UK'37 to provide temperature record in sites with mixed alkenone productions.

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 26 compounds belonging to chemical group 3 (α,β‐unsaturated straight‐chain and branched‐chain aliphatic primary alcohols, aldehydes, acids and esters). They are all currently authorised as flavours in food. The FEEDAP Panel was unable to perform the assessment of non‐2(cis)‐en‐1‐ol [02.112] in the absence of data on its purity. The FEEDAP Panel concludes that hex‐2‐en‐1‐ol [02.020], pent‐2‐en‐1‐ol [02.050], 2‐dodecenal [05.037], nona‐2,4‐dienal [05.071], trans‐2‐nonenal [05.072], hex‐2(trans)‐enal [05.073], 2,4‐decadienal [05.081], hepta‐2,4‐dienal [05.084], deca‐2(trans),4(trans)‐dienal [05.140], dodec‐2(trans)‐enal [05.144], hept‐2(trans)‐enal [05.150], non‐2‐enal [05.171], undec‐2(trans)‐enal [05.184], trans‐2‐octenal [05.190], trans‐2‐decenal [05.191], tr‐2, tr‐4‐nonadienal [05.194], tr‐2, tr‐4‐undecadienal [05.196], hex‐2(trans)‐enyl acetate [09.394] and hex‐2‐enyl butyrate [09.396] are safe at the proposed maximum use level of 5 mg/kg feed for all animal species; nona‐2,6‐dien‐1‐ol [02.049], trans‐2, cis‐6‐nonadien‐1‐ol [02.231], nona‐2(trans),6(cis)‐dienal [05.058], nona‐2(trans),6(trans)‐dienal [05.172], allyl heptanoate [09.097] and allyl hexanoate [09.244] are safe at the proposed normal use levels of 1 mg/kg complete feed for all animal species. No safety concern would arise for the consumer from the use of these compounds up to the highest safe levels in feed. In the absence of studies to assess the safety for the user, the FEEDAP Panel cannot conclude on the safety for the users when handling the additives. No environmental risk is foreseen for these compounds at the concentrations considered safe for the target species. Since the 25 compounds are used in food as flavourings and their function is essentially the same as that in food, no further demonstration of efficacy is necessary.

Oxidative stress is associated with numerous health conditions and disorders, and aldehydes are known biomarkers of oxidative stress that can be non-invasively measured in exhaled human breath. Few studies report breath aldehyde levels in human populations, and none claim participant numbers in the hundreds or more. Further, the breath community must first define the existing aldehyde concentration variance in a normal population to understand when these levels are significantly perturbed by exogenous stressors or health conditions. In this study, we collected breath samples from 692 participants and quantified C(4)–C(10) straight chain aldehyde levels. C(9) aldehyde was the most abundant in breath, followed by C(6). C(4) and C(5) appear to have bimodal distributions. Post hoc, we mined our dataset for other breath carbonyls captured by our assay, which involves elution of breath samples onto a solid phase extraction cartridge, derivatization and liquid chromatography-quadrupole time of flight mass spectrometry (LC-qTOF). We found a total of 21 additional derivatized compounds. Using self-reported demographic factors from our participants, we found no correlation between these breath carbonyls and age, gender, body mass index (BMI), ethnicity or smoking habit (tobacco and marijuana). This work was preceded by a small confounders study, which was intended to refine our breath collection procedure. We found that breath aldehyde levels can be affected by participants’ using scented hygiene products such as lotions and mouthwashes, while collecting consecutive breath samples, rinsing the mouth with water, and filtering inspired air did not have an effect. Using these parameters to guide our sampling, subjects were instructed to avoid the prior conditions to providing a breath sample for our study.

Straight-chain alkanediols such as ethylene glycol are commonly found in our daily life as they are used to produce cosmetics, antifreezes, polyesters and polyurethanes. In this article, we report on the promising potential use of straight-chain alkanediols for rewritable full-colour imaging applications by the preparation of glassy cholesteric liquid crystals (G-CLCs). A series of straight-chain alkanediol derivatives possessing two cholesteryl groups through carbonate ester linkages (Cn-DiCh) showed thermotropic cholesteric liquid crystal phase with visible reflection. The thermally induced shifting ranges of reflection peaks were dependent on the central carbon chain length (n) of Cn-DiCh. Although the pristine Cn-DiCh showed narrow wavelength ranges of the reflection peaks by changing the temperature, we successfully prepared a mixture of two different kinds of Cn-DiCh at their equivalent weight ratio, which exhibited the reflection peak shift throughout a wide visible-wavelength range between 400 nm and 850 nm. Moreover, the binary mixtures of Cn-DiCh were rapidly cooled from the CLC temperatures to 0°C, whereupon the reflection colours could be preserved even at room temperature over 2 months. Such rapid cooling treatment enabled the straightforward preparation of solid-state G-CLCs with visible reflection characteristics, thereby leading to the applications of rewritable full-colour imaging media.

Low-dimensional halide perovskites have recently attracted intense interest as alternatives to the three-dimensional (3D) perovskites because of their greater tunability and higher environmental stability. Herein, we present the new homologous 2D series (NH3CmH2mNH3)(CH3NH3)n−1PbnI3n+1 (m = 4–9; n = 1–4), where m represents the carbon-chain number and n equals layer-thickness number. Multilayer (n > 1) 2D perovskites incorporating diammonium cations were successfully synthesized by the solid-state grinding method for m = 4 and 6 and by the solution method for m = 7–9. Structural characterization by single-crystal X-ray diffraction for the m = 8 and m = 9 series (n = 1–4) reveals that these compounds adopt the Cc space group for even n members and Pc for odd n members. The optical bandgaps are 2.15 eV for two-layer (n = 2), 2.01 eV for three-layer (n = 3), and 1.90 eV for four-layer (n = 4). The materials exhibit excellent solution processability, and casting thin-films of the n = 3 members was successfull...

Biomedical research in areas such as metabolic disorders, neuromodulatory, and immunomodulatory conditions involves lipid metabolism and demands a reliable and inexpensive method for quantification of short chain fatty acids (SCFAs). We report a GC-MS method for analysis of all straight-chain and branched-chain SCFAs using pentafluorobenzyl bromide (PFBBr) as derivatization reagent. We optimized the derivatization and GC-MS conditions using a mixture containing all eight SCFA standards, i.e., five straight-chain and three branched-chain SCFAs. The optimal derivatization conditions were derivatization time 90 min, temperature 60 (°)C, pH 7, and (CH(3))(2)CO:H(2)O ratio 2:1 (v:v). Comparing the performance of different GC column configurations, a 30 m DB-225ms hyphenated with a 30 m DB-5ms column in tandem showed the best separation of SCFAs. Using the optimized experiment conditions, we simultaneously detected all SCFAs with much improved detection limit, 0.244 - 0.977 μM. We further applied the developed method to measure the SCFAs in mouse feces and all SCFAs were successfully quantified. The recovery rates of the eight SCFAs ranged from 55.7% to 97.9%.

The predominant enantiomer of nicotine found in nature is (S)-nicotine and its pharmacology has been widely established. However, pharmacologic information concerning individual enantiomers of nicotine-related compounds is limited. Recently, a modified macrocyclic glycopeptide chiral selector was found to be highly stereoselective for most tobacco alkaloids and metabolites. This study examines the semi-synthetic and native known macrocyclic glycopeptides for chiral recognition, separation, and characterization of the largest group of nicotine-related compounds ever reported (tobacco alkaloids, nicotine metabolites and derivatives, and tobacco-specific nitrosamines). The enantioseparation of nicotine is accomplished in less than 20s for example. All liquid chromatography separations are mass spectrometry compatible for the tobacco alkaloids, as well as their metabolites. Ring-closed, cyclized structures were identified and separated from their ring-open, straight chain equilibrium structures. Also, E/Z-tobacco-specific nitrosamines and their enantiomers were directly separated. E/Z isomers also are known to have different physical and chemical properties and biological activities. This study provides optimal separation conditions for the analysis of nicotine-related isomers, which in the past have been reported to be ineffectively separated which can result in inaccurate results. The methodology of this study could be applied to cancer studies, and lead to more information about the role of these isomers in other diseases and as treatment for diseases.

espanolIntroduccion: el dolor lumbar es una condicion con mayor indice de consulta en los servicios de salud. En trabajadores de oficina tambien existe una alta prevalencia, por lo tanto es necesario generar planes de intervencion desde la prevencion primaria para mejorar la condicion de salud de esta poblacion. Objetivo: determinar los efectos de un programa de ejercicio sobre el dolor lumbar en trabajadores de oficina. Materiales y metodos: se realizo un programa de ejercicio en 17 trabajadores de oficina en una empresa de Bogota durante cuatro semanas basado en el fortalecimiento de los musculos abdominales, profundos del cuello y el estiramiento de la cadena recta posterior. Se evaluo la evolucion del dolor lumbar y la incapacidad laboral por medio del cuestionario de Roland Morris, los instrumentos se aplicaron al finalizar las cuatro semanas de intervencion con seguimiento a los seis meses. Resultados: se evidencio una disminucion del dolor en dos unidades luego de las cuatro semanas de intervencion (p EnglishIntroduction: lumbar pain is a condition catalogued as one with the higher rate of medical services consultation. In office workers there is also a high prevalence, thus is necessary to generate intervention plans since primary intervention encourage improvement in health status of this population. Objective: to determine the effects of an exercise plan on low back pain in office workers. Material and method: it was conducted an exercise plan in the office based in the strengthening of the abdominal girdle, the neck´s deep muscles and the stretching of back straight chain in 17 workers of a company located in Bogota, for four weeks, and evolution respect to low back pain was evaluated through the Roland Morris questionnaire. Tools were applied at the end of the four weeks intervention and follow-up at six months was performed. Results: a decrease in pain by two units is evident after four weeks of intervention (p

Students of single crystal X-ray diffraction are often give advice as to how best to collect their data when attempting absolute configuration determination. These ‘rules’ often have more grounding in gut-feeling than evidence. Thus, in an effort to provide advice and evidence that today’s crystallographers can pass onto to tomorrow’s young scientists, we present a systematic study of 1-deoxy- l -arabinitol, a straight chain sugar which crystalises well in the space group I 4 1 .

Cyclodextrins have been extensively used for inclusion of various drugs for improvement of pharmaceutical characteristics of diverse nature. Numerous derivatives of cyclodextrins are currently available and are being subjected to continuous investigations. On the other hand, urea was previously being used as host for inclusion of straight chain linear compounds. However, development of a modified technique has opened flood gates for inclusion of non-linear drugs containing cyclic moieties. Cis-retinoic acid, nicorandil, vitamin E, amiloride, glipizide, enalapril maleate, simvastatin, lafutidine and ezetimbe are some of the drugs which have already been investigated for improvement of pharmaceutical characteristics. These characteristics include improvement of stability, content uniformity, dissolution profile and rheological behavior. Recently, pesticide-fertilizer combination has also been reported to serve the dual purpose of pesticide cum fertilizer and for improvement in safe handling and formulation characteristics. All FDA approved cyclodextrins are safe chemicals for human use within permissible limits. Urea is a component of normal physiological processes of body in human beings and other mammals. Urea is far cheaper when compared to cyclodextrins. Studies reveal that despite unique characteristics of urea like high solubility, non-toxicity, stability, inexpensiveness, biodegradability and easy availability, the use of urea as a host for inclusion of drugs has been grossly overlooked by researchers. Immense potential of urea as a host for inclusion of drugs need to be explored for improvement of pharmaceutical characteristics. The relative use of both cyclodextrins and urea as hosts for inclusion of drugs has been briefly reviewed in the present article.

[EN] Linear even-carbon-number alpha-olefins (LAO) with four or more carbon atoms are important compounds of high demand in chemical industry as precursors of a wide range of value-added chemicals [1]. LAO are used as co-monomers for polyethylene production, for the production of alcohols (mainly in detergents and plasticizers) and for synthesis of polyalphaolefins (used in synthetic lubricants). Alpha-olefins (C4, C6, C8 and C10) are mainly used to produce poly(vinyl chloride) plasticizers, high-density and linear low-density polyethylene to impart the stress-crack resistance. C10–C14 alpha-olefins can be used to synthesize linear alkylbenzene sulfonates (synthetic detergents). A conventional route to produce alpha-olefins is oligomerization of ethylene. The process provides production of high quality alpha-olefins but is very costly. If not oligomerization, LAO can be produced by thermal cracking of waxy paraffins but the product is not pure and contains numerous internal olefins, dienes and paraffin impurities. The process is conducted in the vapor phase at relatively low cracking temperatures and needs rapid quenching to prevent side reactions such as isomerization or cyclization. In our previous work [2], we showed that the selectivity to alpha-olefins can be increased considerably via catalytic cracking of n-alkanes under selective MW heating of catalysts. In the present work, the general regularities of MW cracking of n-alkanes are presented. Porous ceramic matrix Al2O3/Al composites (ceramometals) and various carbon materials (CM) having high dielectric losses were studied as supports of the catalysts. MW cracking was conducted with n-C16H34 and n-C28H58. The influence particle size and surface morphology of ceramometals and CM on the structural and group composition of the products was studied. It was established that LAO (C2-C23) and n-alkanes (C2-C26) were the main cracking products under selective MW heating of the used supports. The quantitative analysis of the products demonstrated that the liquid-phase process is more selective to alpha-olefins at the MW catalytic cracking than at the convectional thermal cracking. Silica modification of the surface of CM was shown to suppress spark discharge (usually observed at MW heating of CM); hence, the thermal cleavage of C-C bonds on the CM surface but not in the plasma discharge contributes the most to the formation of radicals. It was shown that the selectivity to liquid alpha-olefin could be more than 85 % under MW heating of cermets in region of the E - field node and decrease considerably in the region of H - field node., The research was supported by RSF (project No. 17-73-30032).

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate 54 flavouring substances attributed to the Flavouring Group Evaluation 05 (FGE.05), using the Procedure as referred to in the Commission Regulation (EC) No 1565/2000. This Revision 3 includes 17 additional substances which have been cleared with respect to genotoxicity in FGE.200Rev1 ([FL‐no: 02.192, 02.231, 05.072, 05.144, 05.184, 05.189, 05.190, 05.191, 05.195, 09.247, 09.400, 09.866, 09.948]) and in FGE.203Rev2 ([FL‐no: 05.081, 05.186, 05.194, 05.196]). The substances were evaluated through a stepwise approach that integrates information on the structure–activity relationships, intake from current uses, toxicological threshold of concern (TTC), and available data on metabolism and toxicity. The Panel concluded that none of the 54 substances gives rise to safety concern at their levels of dietary intake, estimated on the basis of the ‘Maximised Survey‐derived Daily Intake’ (MSDI) approach. Besides the safety assessment of the flavouring substances, the specifications for the materials of commerce have also been considered and found adequate, except for 10 substances ([FL‐no: 08.072, 08.083, 08.101, 08.119, 08.120, 09.181, 09.329, 09.335, 09.379 and 09.637]) for which quantitative figures on the composition of stereoisomeric mixtures are missing and for [FL‐no: 09.578] complete specifications should be provided. Normal and maximum use levels were not available for [FL‐no: 08.072, 08.083, 08.101, 08.119, 08.120, 09.287, 09.326 and 09.578]. Except for flavouring substances [FL‐no: 05.072, 05.081, 05.186, 05.194, 05.196, 09.934 and 09.942], more reliable intake data should be requested for all the 46 flavouring substances, for which use levels were submitted, as their modified Theoretical Added Maximum Daily Intake (mTAMDI) exposure estimates are above the threshold of concern for structural classes I and II. This would include more reliable intake data and then, if required, additional toxicological data.

Owing to their apparent lack of health significance, higher straight-chain aliphatic aldehydes, i.e., those having alkyl chains with more than six carbon atoms, have been largely neglected in food and nutraceutical research. However, they are an important class of odor-active volatiles in human foods. Indeed, certain aldehydes, such as hexanal, E-2-nonenal, and E, E-2,4-decadienal, serve as key odorants in a range of our foods and drinks. This perspective describes the significance of higher straight-chain aliphatic aldehydes as food odorants, focusing on several representative ones, and raises the issues regarding these aldehydes to be addressed in the future.

Background: Pyropia (Porphyra), commonly known as nori or laver, is an important food source in many parts of the world. Edible dried Pyropia contains numerous nutrients and biofunctional components, including proteins, vitamins, eicosapentaenoic acid, minerals, carotenoids, mycosporine-like amino acids, and carbohydrate, and one of the compounds which we are interested in is porphyran, a sulfated polysaccharide comprising the hot-water-soluble portion of Pyropia cell walls. Researchers have performed a large number of in-depth studies on the biological activity and potential therapeutic applications of porphyrans and oligoporphyrans. Methods: This mini review aims to provide comprehensive and update overview on the source, extraction, structure, biological activities and structure-activity relationships of porphyrans and oligoporphyrans based on the studies in the past 30 years which were included in Web of Science. Results: The structure of porphyran has been basically determined given that its straight chain is relatively simple, and the skeleton structure has been described. The extraction methods were simplified continuously, but different extraction methods and post- processing methods still had great influence on the structure and composition of porphyran, so there was no standardized extraction process which can achieve quality control until now. In order to obtain oligoporphyrans, there are a variety of degradation methods, including chemical method, physical method and enzymatic method, but it is worth mentioning that specific degradation enzyme is still unavailable. Studies on the biological and pharmacology properties include antioxidant, anti-tumor, anti-inflammatory, immunomodulation, anti-cardiovascular and cerebrovascular diseases and drug delivery. Conclusion: Owing to the therapeutic potential and drug delivery applications, porphyran and oligoporphyrans are expected to be further developed as a medicine against human diseases, as well as a supplement in cosmetics and health products.

The Dulux Archives in Melbourne hold a set of four laboratory notebooks written by Brian Roberts while a trainee paint chemist at British Australian Lead Manufacturers (BALM) Pty. Ltd. in 1949. This paper focuses on information contained in the notebooks detailing company testing and practical tools for managing known zinc oxide reactivity in oil-based house paints. Acceptable application and weathering properties of zinc oxide in oil paint formulations emphasized good quality larger particle size zinc oxide pigment at correct pigment volume ratio, appropriate driers and importantly, the use of stand oil. The notebooks provide a prompt to consider the effect of the stand reaction on linseed oil acids and subsequent soap formation. Although stand oils can contain a high proportion of acids available for reaction with zinc ions, due to Diels-Alder reactions during the stand process a proportion have likely become cyclic. The subsequent cyclic zinc carboxylates may inhibit aggregation and crystallisation and thus may be less problematic in paint films than zinc carboxylates of the straight chain fatty acids found in untreated linseed oil – rendering zinc oxide in stand oil more stable.

Cuticular hydrocarbons (CHCs) have evolved as a communication cues and they play a significant role in the life of social insect. Although the primary function is to prevent desiccation, CHCs are also used in recognition of individuals and insect gregariousness. In this paper we examined the CHCs composition of queens, workers and drones of Apis cerana indica. CHCs analysis by Gas Chromatography – Mass Spectrometry revealed 45 different molecules. In drones, 21–37 carbon chain length hydrocarbons comprising of a complex mixture of alkanes, alkenes, mono-, di-, tri-methyl alkanes and alkadienes were detected. Alkanes of drones resemble those found in workers except pentacosane and triacontane which was not detected in the latter. Workers showed pentacosane, heptacosane, 11-Methyl-heptacosane, 13-Methyl-heptacosane, nonacosane, nonacosene, 13-Methyl-nonacosane and 15-Methyl-nonacosane as major CHCs. Workers had an equal number of straight alkanes and alkenes but differing in their proportions and also containing fewer branched hydrocarbons with chain lengths ranging from 21–37 carbons. Further, workers had significantly higher concentration of nonacosene, pentatriacontene, heptatriacontene as compared to drones. In queens much simpler and straight chain hydrocarbons with carbon chain ranging from 21–37 were detected. Several branched hydrocarbons as compared to drones and workers were absent. Queens had a higher concentration of alkanes than workers and drones.

Spatially controlled in vivo sampling by contact solid phase microextraction with a non-coated silica fiber combined with gas chromatography-mass spectrometry (GC-MS) was utilized for hydrocarbon profiling in tarsal adhesion secretions of four insect species (Nicrophorus vespilloides, Nicrophorus nepalensis, Sagra femorata, and Gromphadorhina portentosa) by using distinct adhesion systems, viz. hairy or smooth tarsi. For comparison, corresponding samples from tibiae, representing the general cuticular hydrocarbon profile, were analyzed to enable the statistical inference of active molecular adhesion principles in tarsal secretions possibly contributed by specific hydrocarbons. n-Alkanes, monomethyl and dimethyl alkanes, alkenes, alkadienes, and one aldehyde were detected. Multivariate statistical analysis (principal component and orthogonal partial least square discriminant analyses) gave insights into distinctive molecular features among the various insect species and between tarsus and tibia samples. In general, corresponding hydrocarbon profiles in tarsus and tibia samples largely resembled each other, both qualitatively and in relative abundances as well. However, several specific hydrocarbons showed significantly different relative abundances between corresponding tarsus and tibia samples, thus indicating that such differences of specific hydrocarbons in the complex mixtures might constitute a delicate mechanism for fine-tuning the reversible attachment performances in tarsal adhesive fluids that are composed of substances originating from the same pool as cuticular hydrocarbons. Caused by melting point depression, the multicomponent tarsal adhesion secretion, made up of straight chain alkanes, methyl alkanes, and alkenes will have a semi-solid, grease-like consistency, which might provide the basis for a good reversible attachment performance.

Density of binary mixtures of ethyl acetoacetate (EAA) with straight chain aliphatic ketones butan-2-one, pentan-2-one, hexan-2-one, heptan-2-one, octan-2-one and nonan-2-one were measured at varying compositions of the ethyl acetoacetate at 298.15 K. The derived properties such as excess molar volumes, V m E , of the binary mixtures were calculated from the experimental density data of the mixtures. The calculated excess molar volumes were fitted into the Redlich-Kister polynomial to obtain the fitting parameters and standard deviations. The excess molar volumes of the binary mixtures investigated were negative over the entire range of composition. The negative values were attributed to dipole–dipole interactions between the unlike molecules of mixtures than those between the like molecules of the pure solvents. The observed negative values of the excess molar volumes for the studied binary mixtures were discussed in terms of intermolecular interactions which were present in the mixtures.

The straight-chain alkane-assisted synthesis of hierarchical mesoporous silica materials (MSM) results in variable mesostructures and morphologies due to remarkably different self-assembly routes of template agent from those without the assistance of straight-chain alkanes. The textural properties, particularly pore size, channel structure, morphology, and hierarchical structure of those MSM make them demonstrate peculiar effects in the immobilization of homogeneous catalysts.

To explore candidate pesticides from non-food bioactive products, twenty-five new matrine-type alkaloid analogs, 15-chloro-18-(acyl)oximinylmatrines (6a–6y), were semi-synthesized from matrine isolated from the roots of Sophora flavescens Aiton (Fabaceae). The spatial configurations of six derivatives were determined by X-ray crystallography. Analogs 6f (R = (CH2)9CH3) and 6g (R = (CH2)10CH3) all showing the pronounced insecticidal and acaricidal activities against two threatening pests Mythimna separata Walker and Tetranychus cinnabarinus Boisduval, could be used as the lead compounds for further structural optimization. It suggested that R as the aliphatic alkane with long straight chain was necessary for the insecticidal and acaricidal activities of matrine oximino esters.

The Panel on Food Additives and Flavourings of the European Food Safety Authority was requested to evaluate the genotoxic potential of 74 flavouring substances from subgroup 1.1.1 of FGE.19 in the Flavouring Group Evaluation 200 Revision 1 (FGE.200 Rev1). In FGE.200, genotoxicity studies were provided for one representative substance, namely hex‐2(trans)‐enal [FL‐no: 05.073], and for other two substances in the same subgroup, namely 2‐dodecenal [FL‐no: 05.037] and 2‐nonenal [FL‐no: 05.171]. The Panel concluded that the concern still remains with respect to genotoxicity for the substances of this subgroup and requested an in vivo Comet assay performed in duodenum and liver for hex‐2(trans)‐enal [FL‐no: 05.073]. For the two other representative substances of subgroup 1.1.1 (nona‐2(trans),6(cis)‐dienal [FL‐no: 05.058] and oct‐2‐enal [FL‐no: 05.060]), the Panel requested a combined in vivo Comet assay and micronucleus assay. These data have been provided and are evaluated in the present opinion FGE.200 Rev1. Industry submitted genotoxicity studies on trans‐2‐octenal [FL‐no: 05.190], instead of oct‐2‐enal [FL‐no: 05.060]. Based on the available data, the Panel concluded that the concern for genotoxicity can be ruled out for hex‐2(trans)‐enal [FL‐no: 05.073], trans‐2‐octenal [FL‐no: 05.190] and nona‐2(trans),6(cis)‐dienal [FL‐no: 05.058], therefore all the 74 substances [FL‐no: 02.020, 02.049, 02.050, 02.090, 02.112, 02.137, 02.156, 02.192, 02.210, 02.231, 05.037, 05.058, 05.060, 05.070, 05.072, 05.073, 05.076, 05.078, 05.102, 05.109, 05.111, 05.114, 05.120, 05.144, 05.150, 05.171, 05.172, 05.179, 05.184, 05.189, 05.190, 05.191, 05.195, 06.025, 06.031, 06.072, 09.054, 09.097, 09.109, 09.119, 09.146, 09.233, 09.244, 09.247, 09.276, 09.277, 09.303, 09.312, 09.385, 09.394, 09.395, 09.396, 09.397, 09.398, 09.399, 09.400, 09.410, 09.411, 09.469, 09.482, 09.489, 09.492, 09.493, 09.498, 09.678, 09.701, 09.719, 09.741, 09.790, 09.841, 09.866, 09.947, 09.948, 13.004] can be evaluated through the Procedure for flavouring substances.

The Panel on Food Additives and Flavourings of the European Food Safety Authority was requested to evaluate the genotoxic potential of 74 flavouring substances from subgroup 1.1.1 of FGE.19 in the Flavouring Group Evaluation 200 Revision 1 (FGE.200 Rev1). In FGE.200, genotoxicity studies were provided for one representative substance, namely hex-2(trans)-enal [FL-no: 05.073], and for other two substances in the same subgroup, namely 2-dodecenal [FL-no: 05.037] and 2-nonenal [FL-no: 05.171]. The Panel concluded that the concern still remains with respect to genotoxicity for the substances of this subgroup and requested an in vivo Comet assay performed in duodenum and liver for hex-2(trans)-enal [FL-no: 05.073]. For the two other representative substances of subgroup 1.1.1 (nona-2(trans),6(cis)- dienal [FL-no: 05.058] and oct-2-enal [FL-no: 05.060]), the Panel requested a combined in vivo Comet assay and micronucleus assay. These data have been provided and are evaluated in the present opinion FGE.200 Rev1. Industry submitted genotoxicity studies on trans-2-octenal [FL-no: 05.190], instead of oct-2-enal [FL-no: 05.060]. Based on the available data, the Panel concluded that the concern for genotoxicity can be ruled out for hex-2(trans)-enal [FL-no: 05.073], trans-2-octenal [FL-no: 05.190] and nona-2(trans),6(cis)-dienal [FL-no: 05.058], therefore all the 74 substances [FL-no: 02.020, 02.049, 02.050, 02.090, 02.112, 02.137, 02.156, 02.192, 02.210, 02.231, 05.037, 05.058, 05.060, 05.070, 05.072, 05.073, 05.076, 05.078, 05.102, 05.109, 05.111, 05.114, 05.120, 05.144, 05.150, 05.171, 05.172, 05.179, 05.184, 05.189, 05.190, 05.191, 05.195, 06.025, 06.031, 06.072, 09.054, 09.097, 09.109, 09.119, 09.146, 09.233, 09.244, 09.247, 09.276, 09.277, 09.303, 09.312, 09.385, 09.394, 09.395, 09.396, 09.397, 09.398, 09.399, 09.400, 09.410, 09.411, 09.469, 09.482, 09.489, 09.492, 09.493, 09.498, 09.678, 09.701, 09.719, 09.741, 09.790, 09.841, 09.866, 09.947, 09.948, 13.004] can be evaluated through the Procedure for flavouring substances.

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of flavouring substances from subgroup 1.1.4 of FGE.19 in the Flavouring Group Evaluation 203 Revision 2 (FGE.203Rev2). In FGE. 203 Revision 1, the Panel concluded that the genotoxic potential could not be ruled out for the flavouring substances in this FGE. The Flavour Industry provided additional genotoxicity studies for the representative substances of FGE.19 subgroup 1.1.4, namely deca-2(trans),4(trans)-dienal [FL-no: 05.140] and hexa-2(trans),4(trans)-dienal [FL-no: 05.057]. In addition, new studies on hepta2,4-dienal [FL-no: 05.084], 2,4-octadienal [FL-no: 05.186] and tr-2,tr-4-nonadienal [FL-no: 05.194] were provided that are evaluated in the present revision of FGE.203, i.e. FGE.203Rev2. Hepta2,4-dienal [FL-no: 05.084], 2,4-octadienal [FL-no: 05.186] and tr-2,tr-4-nonadienal [FL-no: 05.194] did not induce gene mutations in bacteria. Hexa-2(trans),4(trans)-dienal [FL-no: 05.057] did not induce gene mutations in vitro in mammalian cells. Hexa-2(trans),4(trans)-dienal [FL-no: 05.057] was also tested in an in vivo gene mutation assay giving negative results. Both hexa-2(trans),4(trans)-dienal [FL-no: 05.057] and deca-2(trans),4(trans)-dienal [FL-no: 05.140] were tested in vivo for the induction of micronuclei in rats bone marrow and peripheral reticulocytes after oral or intraperitoneal administration. None of the two substances induced increased frequencies of micronuclei. The Panel concluded that the concern for genotoxicity can be ruled out for the representative substances hexa-2(trans),4(trans)-dienal [FL-no: 05.057] and deca-2(trans),4(trans)-dienal [FL-no: 05.140] and therefore also for the other substances in this group [FL-no: 02.139, 02.153, 02.162, 02.188, 05.064, 05.071, 05.081, 05.084, 05.101, 05.108, 05.125, 05.127, 05.141, 05.173, 05.186, 05.194, 05.196, 09.573]. These 20 substances can be evaluated using the Procedure for the evaluation of flavouring substances.

The influences of the number of the ammonium groups and their arrangement manner on the photophysical properties of the quaternized zinc phthalocyanines were studied. The aggregation tendency, singlet oxygen generation ability and the fluorescence intensity properties of the quaternized zinc phthalocyanines were studied and compared. Results indicated that more quaternized ammonium groups and the straight chain arrangement manner for the quaternized zinc phthalocyanines can decrease aggregation degree and increase singlet oxygen generation and fluorescence intensity.

Fluorinated surfactants are usually composed of a perfluorinated chain and a hydrophilic group. Academic surveys have reported that straight chain fluorinated surfactants have the lowest surface tension in a relatively high concentration while the branched fluorinated surfactants show more efficient in a relatively low concentration. Introducing branch is one of effective strategies for synthesis of non-bioaccumulable fluorinated surfactants. Three novel branched fluorinated surfactants were designed and prepared through a five-step route using perfluoro-2-methyl-2-pentene as starting material. The surface activities of them were investigated and found that they exhibited excellent surface activities. FCS can reduce the surface tension of water to below 20 mN/m, and the cmc value of FAS in water is about 1.04 × 10−4 mol/L at 298 K. All the values of surface properties of FCS, FGS and FAS are lower than that of sodium perfluorooctanoate.

Alkane-1,1-bistriflates, prepared in excellent yields by reaction of aldehydes with triflic anhydride, are converted to their respective 1,1-difluoroalkanes in good to excellent yield through reaction with fluorinating agent, triethylaminetrishydrofluoride. Straight chain 1,1-bistriflates are more reactive than those substituted at the 2-position, but the latter are also converted successfully, without evidence of any rearrangement products.

With the fast development of nanotechnology, accurate measurement and classification of nanoparticles are in great need. Nanoparticles frequently appear in non-spherical forms such as long aspect ratio nanofibers, nanotubes, and irregular nano-agglomerates. While the well-developed classical studies were mainly in continuum regime with spherical particles, dynamics of the non-spherical nanoparticles is not fully understood. In this study, orientation-averaged mobility of nanofiber and nanorod (with no preferred alignment) is examined by the methods of Brownian diffusion theory, a combination of collision limited reaction rate theory and the bipolar diffusion charging analysis. Comparisons to empirical predictions from the experimental measurements are also made. The study leads to the discovery of a surface-dominated mobility for high aspect ratio nanoparticles with characteristic Knudsen number greater than 5. In view of the extreme relative length scales between particle size and the gas mean free path, particles of all morphologies can be viewed as point collisions; therefore, the equivalent surface mobility diameter is reasonably justified. This finding has been verified in the current study with high aspect ratio particles. For non-spherical particles of more general forms, further investigation is needed. As expected, accuracy of this approximation reduces as the characteristic Knudsen number decreases. When Kn(dL) < 0.1, the study shows that particle morphology starts to play an important role. A review of particle mobility for all Knudsen number flows is also provided. © 2017 American Association for Aerosol Research

Comparison theorems on resistance distances and Kirchhoff indices of the so-calledS- &T-isomer graphs are established. Then these results are applied to compare Kirchhoff indices of hexagonal chains, showing that the straight chain is the unique chain with maximum Kirchhoff index, whereas the minimum Kirchhoff index is achieved only when the hexagonal chain is an ''all-kink'' chain.

This article describes the methods for collecting automated solutions in intellectual systems. This article features conclusive methods based on the forward and reverse chains, the difference between the method of straight chain and the method of the inverse chain. This article describes methods of finding solutions in the state space, the difference between in-depth and breadth-first research. A backtracking method is described. The reduction method is revealed. The article shows the limits of applicability of methods and provides a comparison of described methods with the method of precedents.

How to overcome the friction between the micro components has become a key point of the successful operation of the micro/nano-electric mechanical systems. The understanding of the friction mechanism of the alkane liquid film confined between two substrates is important when the friction law on a macro/nano scale is not applicable. In this work, the molecular dynamics simulations are used to study the effect of the chain length on the friction properties of the liquid films that are confined between two golden substrates. There are seven pure alkane liquid films that are composed of one molecule CnH2n + 2(n = 6, 8, 10, 12, 14, 16, 18), and six mixed alkane liquid films that are composed of two molecules C6H14/CnH2n + 2(n = 8, 10, 12, 14, 16, 18) with a ratio of 1∶1. The results show that the friction force and the coefficient of friction of pure alkane liquid films both increase as the chain length increases when the carbon atom number is less than 12, whereas the friction property keeps stable when the carbon atom number of the alkane molecule is greater than 10 and the pure hexadecane liquid film has the largest friction force. In the mixed films, the addition of short chain alkane molecules can strengthen the friction, and the hexane/dodecane mixed film has the maximum friction force. The short chain molecule dilutes the C8H18 film and C10H22 film which cause the friction force to decrease. During the sliding progress, the formation of solid-like high density-packet layers is the main reason for the friction reduction. When no solid-like layer or just one solid-like layer is formed at the interface of golden base, the liquid alkane film is liquid-like and its viscosity becomes much larger than that in the normal state, which leads to high friction force. The short chain molecules reduce the density of the solid-like layers, which causes the film to transform from solid-like state to liquid state, thus resulting in the increase of friction. The friction property mainly depends on the layered structure, and the interaction between the golden surface and liquid film contributes to the friction. This study helps to understand the friction mechanism of ultra-thin liquid films.

After completely hydrogenation of Fischer–Tropsch synthesis (FTS) products on Pt/C catalyst, the branched C8, C10, C11, and C12 alkanes were identified using authentic samples to be methyl branched alkanes in both Co and Fe catalyzed reactions. No detectable ethyl branched and dimethyl branched alkanes were observed. The total amount of branched hydrocarbons in Co catalyzed FTS is about 5 % while the amount of branched hydrocarbons in Fe catalyzed FTS is about 25 %. The branched hydrocarbon distribution of Co catalyzed FTS does not obey the Anderson–Schulz–Flory (ASF) kinetics and the branched hydrocarbon distribution of Fe catalyzed FTS shows larger α value than that of straight chain alkanes. These results were explained by the formation of 2-alkylidene through readsorbed 1-alkenes, which can grow to form methyl branched hydrocarbons. Since the rate of propagation of 2-alkylidene is much slower than that of ethylidene and 1-alkylidenes, a “kink” will result in C2 in the FT product distribution plot.

The critical pressures pc and the critical temperatures Tc of diols with straight alkylchains HO(CH2)nOH and n = 3, 4, 5, 6, 8, 9, 10, 12 have been measured. All the alkanediols studied decompose at near-critical temperatures. A pulse-heating method which allows measuring the critical properties of thermally unstable compounds has been used. The times of heating from the beginning of a pulse to the moment of reaching the critical temperature were from (0.03 to 0.46) ms. The short residence times provided little degradation of the substances in the course of the experiments. The uncertainties of the measurement of the critical properties of alkanediols are 0.04 pc and 0.015 Tc, where Tc is the absolute temperature. The critical properties obtained have been compared with the values measured earlier by various techniques. The experimental critical constants of alkanediols have also been compared with those calculated using the group-contribution methods of Lydersen, Wilson and Jasperson, and Marrero and Gani.

Hyperbranched silicone oil was prepared using low-polyhydrosiloxane and vinyl terminated methylphenyl silicone oil as the raw materials through hydrosilylation reaction. The structures and properties of hyperbranched silicone oil were characterized through 1H NMR, TG and dynamic viscosity. The influence on synthesis of hyperbranched silicone oil was discussed, which was caused by ratio of different raw materials. When molar ratio of Si-H bond and Si-Vi bond of raw materials was 3.5:1 (mol), the reaction degree of hyperbranched silicone oils double bond was as high as 80%. At room temperature and 100°C, comparing the dynamic viscosity of hyperbranched silicone oil and straight chain silicone oil, we found that viscosity decrease rate of hyperbranched silicone oil was obviously lower. TG curve of hyperbranched silicone oil and straight chain silicone oil also certified that the hyperbranched silicone oil has higher thermal stability than the straight chain phenyl silicone oil. Therefore hyperbranched silicone oil is more suitable for the preparation of high-performance elastic clay than straight chain silicone oil.

Hydrazides reacted with acylpyruvic acid esters possessing a terminal straight chain alkyl substituent at the C=O bond distal from the ester group, giving 5-hydroxy-2-pyrazolines. Acylpyruvates with bulky terminal substituents underwent condensation at the C=O bond adjacent to the ester group, giving products with hydrazone or 5-hydroxy-2-pyrazoline structure and capable of displaying ring-chain equilibrium between these tautomers in solution.

The conjugate addition on a natural bioactive pseudoguaianolide sesquiterpene lactone parthenin with various Grignard reagents leads to 13-C alkylated products chemo and diastereoselectively in fair overall yields. Compared with other Grignard reagents vinyl and smaller straight chain alkyl Grignard reagents gave better yields.

An Advanced Heavy Water Reactor (AHWR) has been specifically designed to exploit Th/233U as fuels. The reprocessing is focused mainly on the recovery of 233U and Pu from the spent fuels leaving bulk of Th (∼100 g/L) in the High Level Waste (HLW) solutions. No systematic attempts have been made so far to identify suitable solvents for the recovery of thorium from high level waste (HLW) solutions generated after AHWR spent fuel reprocessing. Tri-n-butyl phosphate (TBP), though the work horse for nuclear fuel reprocessing as an extractant, suffers from the serious limitation of third-phase formation during the extraction of macro concentrations of thorium. Two straight chain dialkyl amides such as N,N-dihexyl octanamide (DHOA), and N,N-dihexyl decanamide (DHDA) as well as TBP were evaluated for the recovery of the thorium from AHWR-HLW solutions. Attempts were made to identify suitable solvent (extractant + diluent) system and optimize the conditions for the recovery of thorium from HLW solutions. Selectivit...

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 24 compounds belonging to chemical group 4 (non‐conjugated and accumulated unsaturated straight‐chain and branched‐chain, aliphatic primary alcohols, aldehydes, acids, acetals and esters). This opinion concerns 23 compounds from this group. They are currently authorised as flavours in food. The FEEDAP Panel established the following conclusions: hex‐3(cis)‐en‐1‐ol [02.056], (Z)‐non‐6‐en‐1‐ol [02.093], oct‐3‐en‐1‐ol [02.094], non‐6(cis)‐enal [05.059], hex‐3(cis)‐enal [05.075], (Z)‐hept‐4‐enal [05.085], hex‐3(cis)‐enyl acetate [09.197], hex‐3(cis)‐enyl formate [09.240], hex‐3‐enyl butyrate [09.270], hex‐3‐enyl hexanoate [09.271] and hex‐3(cis)‐enyl isobutyrate [09.563] are safe at the proposed maximum use level of 5 mg/kg complete feed for all target species; citronellol [02.011], (‐)‐3,7‐dimethyl‐6‐octen‐1‐ol [02.229], citronellal [05.021], 2,6‐dimethylhept‐5‐enal [05.074], citronellic acid [08.036], citronellyl acetate [09.012], citronellyl butyrate [09.049], citronellyl formate [09.078] and citronellyl propionate [09.129] are safe at the maximum use level of 5 mg/kg for all species, except cats for which the proposed normal use level of 1 mg/kg is considered safe; undec‐10‐enal [05.035], 1‐ethoxy‐1‐(3‐hexenyloxy)ethane [06.081] and hex‐3‐enyl isovalerate [09.505] are safe at the normal use levels of 1 mg/kg for all species. No safety concern would arise for the consumer from the use of these compounds up to the highest safe level in feeds. Hazards for skin and eye contact, and respiratory exposure are recognised for the majority of the compounds under application. Most are classified as irritating to the respiratory system. The use of the majority of the compounds in animal feed at the maximum safe level is considered safe for the environment. As all the compounds under assessment are used in food as flavourings, and their function in feed is essentially the same as in food, no further demonstration of efficacy is necessary.

Cuticular hydrocarbons of insects often consist of complex mixtures of straight chain, unsaturated and methyl-branched components with 21 to 40+ carbons. They function to restrict water loss, to prevent a lethal rate of desiccation and serve in chemical communication in many species. This chapter describes the chemistry and chemical ecology of insect hydrocarbons with an emphasis on their role as close range or contact pheromones. Hydrocarbons are formed in oenocytes and their biosynthetic pathways are described. Recent work has begun to take advantage of the tools of molecular biology to better understand hydrocarbon formation and this information is summarized. The various methods by which insects utilize hydrocarbons as inter- and intraspecific chemical signals are also described.

A novel series of 2-acetamido and 2 or 3-propanamido derivatives of 4- or 5-substituted-thiazoles was designed and synthesized. Structure elucidation of the new synthesized compounds was attained by the use of 1 H & 13 C NMR, and Mass spectrometry. Compounds were subjected to NCI in vitro assessment for their antitumor activity, at a single dose of 10 μM of test compounds. Compounds bearing straight chain substituent or 4-phenyl function proved to be more active than their branched or 4-methyl congeners. Compounds 37 , 41 and 42 exhibited broad spectrum antitumor activity. Compounds 23 and 27 proved lethal while compounds 18 , 21 , 32 and 37 showed remarkable GI values of 75.5, 69.3, 96.2 and 92.7% to the Leukemia CCRF-CEM cell line, respectively.