Comparison of isolation procedures for Mexican oregano oil

The influence of distillation time on the composition of Mexican oregano oil was investigated. It was observed that the order of recovery of the components was determined by their solubility when water is in contact with the plant material as in hydrodistillation and simultaneous distillation-solvent extraction, while in steam distillation the order was determined by their boiling points. The three methods produced the same composition. The oil obtained by extraction method had higher proportion of hydrocarbons and lower amount of p-cymene. As a result of this investigation it was shown that this compound was partly an artefact of distillation.     

Towards Recyclable Nanoporous Polymer Membranes for the Synthesis of One-dimensional Nanoscale Gold Colloids

Proof-of-concept studies towards recyclable nanoporous track-etched polymer membranes for template-synthesis of one-dimensional colloidal gold rods indicate that surfactant-capped gold nanorods can be synthesised within and isolated from polyethylene terephthalate (Lavsan) membranes using organic solvents with or without sonication. Thereafter, the same Lavsan membrance can be re-used for at least one to two additional synthetic cycles. An erratum to this article can be found at     

Synthesis and Structure of 1,5-Di-(Ethylphenyl)-1,5-Dimethyl-3,3,7,7-Tetraphenylcycloterasiloxane: a Novel Cyclotetramer

Herein we report the first synthesis of 1,5- di-(ethylphenyl)-1,5-dimethyl-3,3,7,7-tetraphenylcyclotetrasiloxane using a new ‘One Pot’ procedure as recently reported for the preparation of strictly alternating 1,1,5,5-tetramethyl-3,3,7,7-tetraphenylcyclotetrasiloxane by the heterofunctional condensation of diphenylsilanediol with (phenylethyl)methyldichlorosilane in the presence of the ter tiary amine, triethylamine (Nguyen et al. Silicon 6:21–26 2014). The prepared 1,5-di-(ethylphenyl)-1,5-dimethyl-3,3,7,7-tetraphenylcyclotetrasi loxane was fully characterized by single-crystal X-ray diffraction, ¹H, ¹³C and ²⁹Si nuclear magnetic resonance spectroscopy, elemental analysis, mass spectroscopy, thermogravimetric analysis and differential scanning calori metric studies.     

Comparison of physicochemical pretreatments of banana peels for bioethanol production

Pretreatments with different concentrations of sulfuric acid (0, 0.5, and 1% v/v) and temperatures (28 and 121 °C at 103 kPa in an autoclave) were performed on banana peels (BP) milled by mechanical grinding and grinding in a blender as well as without grinding. Cellulose, hemicellulose, lignin, ash, and total and reducing sugar contents were evaluated. The highest yields of cellulose enzymatic hydrolysis (99%) were achieved with liquefied autoclaved BP treated with 0.5 and 1% acid after 48 h of hydrolysis. Ethanol production by Kluyveromyces marxianus fermentation was assayed using hydrolyzed BP at 10, 15, and 20% (w/w). The highest ethanol level (21 g/L) was reached after 24 h of fermentation with 20% (w/w) BP. Kinetics of the consumption of reducing sugars under this fermentation condition demonstrates the presence of a lag period (about 8 h). Thus, BP are a good source for ethanol production.     

Analysis of trans–cis fatty acids in fatty acid steryl esters isolated from soybean oil deodoriser distillate

The characterisation of the isolated natural product from soybean oil deodoriser distillate (SODD) has gained increasing importance due to health concerns. The purpose of the present work was to characterise fatty acids steryl esters (FASEs) composition and to determine the trans fatty acids (TFAs) contents in FASEs obtained from SODD by using simple and accurate method. Isolation of FASEs with saturated fatty acids moieties from FASEs mixture was also developed. It was found that the fatty acids composition of the isolated FASEs were 31.74% palmitate acid (C16:0), 9.99% stearic acid (C18:0), 0.46% elaidic acid (C18:1 trans-9), 27.51% oleic acid (C18:1 cis-9), 0.19% linoleaidic acid (C18:2 cis-9, trans-12), and 29.19% linoleic acid (C18:2 cis-9, cis-12). TFAs, which account for about 0.65% of the total fatty acids, were detected in the isolated FASEs. Palmitate and stearate steryl esters isolated from SODD are promising natural product because they are free of trans-isomers.     

The Strain Index (SI) and Threshold Limit Value (TLV) for Hand Activity Level (HAL): risk of carpal tunnel syndrome (CTS) in a prospective cohort

A cohort of 536 workers was enrolled from 10 diverse manufacturing facilities and was followed monthly for six years. Job physical exposures were individually measured. Worker demographics, medical history, psychosocial factors, current musculoskeletal disorders (MSDs) and nerve conduction studies (NCS) were obtained. Point and lifetime prevalence of carpal tunnel syndrome (CTS) at baseline (symptoms + abnormal NCS) were 10.3% and 19.8%. During follow-up, there were 35 new CTS cases (left, right or both hands). Factors predicting development of CTS included: job physical exposure (American conference of governmental industrial hygienists Threshold Limit Value (ACGIH TLV) for Hand Activity Level (HAL) and the Strain Index (SI)), age, BMI, other MSDs, inflammatory arthritis, gardening outside of work and feelings of depression. In the adjusted models, the TLV for HAL and the SI were both significant per unit increase in exposure with hazard ratios (HR) increasing up to a maximum of 5.4 (p = 0.05) and 5.3 (p = 0.03), respectively; however, similar to other reports, both suggested lower risk at higher exposures. Data suggest that the TLV for HAL and the SI are useful metrics for estimating exposure to biomechanical stressors. PRACTITIONER SUMMARY: This study was conducted to determine how well the TLV for HAL and the SI predict risk of CTS using a prospective cohort design with survival analysis. Both the TLV for HAL and the SI were found to predict risk of CTS when adjusted for relevant covariates.