References 1. Kjonaas RA, Williams PE, Counce DA, Crawley LR. Synthesis of Ibuprofen in the Introductory Organic Laboratory. J Chem Educ. 2011;88:825-828. 2. Schurig V. The Importance of Chirality in Nature and Methods of the Separation of Enantiomers by Chiral Chromatography. Arab J Chem. 2008;1:111-122. 3. El-Fatatry HM, Mabrouk MM, Hammad SF, El-Malla SF. A Validated Enantioselective HPLC Method for Determination of Ibuprofen Enantiomers in Bulk and Tablet Dosage Form. J AOAC Int, 2016;99:604-611. 4. Loudiki A, Boumya W, Hammani H, Nasrellah H, El Bouabi Y
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Most ligature cases feature everyday, innately-tied Overhand Knots, Half Hitches and Half Knots. These knots are the result of habitual behaviour and individual tiers demonstrate consistency, except when certain contextual factors come into play. This survey focussed on comparing the chiralities of basic knots to those of Figure Eight Knots, which occur in case evidence and require similar tying actions. It is important to note that real-world Figure Eights are oriented relative to their working ends and are therefore chiral, whereas topological Figure Eights have no ends and are amphichiral. Data summarizing the tying habits of 184 survey respondents were collected and analysed. The majority of volunteers surveyed tied common Overhand Knots and Figure Eights of equal chirality, consistently or nearly consistently, irrespective of any general learning effect. A minority tied knots of opposite chirality. The knots tied by the remaining respondents varied, and the data suggested a potentially complex pattern which may be related to previous findings. Similar but less pronounced patterns were exhibited in the Half Hitch and Half Knot data. This information could be useful when analysing case evidence and making links to suspect samples, provided cautious attention is paid to context and knot function.
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Panthenol is a biologically active compound closely related to vitamin B5 (pantothenic acid). This work deals with the separation of panthenol enantiomers using high performance liquid chromatography. Different types of chiral stationary phases (β-cyclodextrin, isopropyl carbamate cyclofructan 6, amylose tris(3,5-dimethylphenylcarbamate)) were tested in normal phase separation mode. Effect of mobile phase composition on the resolution and retention of enantiomers was studied. Two types of detectors, low-wavelength UV and polarimetric, were used. The optimal chromatographic system includes a chiral stationary phase based on amylose and a mobile phase of hexane/ethanol (60/40, v/v) where the resolution of enantiomers reached the value Rs = 2.49. Suitable chromatographic conditions were applied for the determination of panthenol enantiomers in samples of pharmaceutical preparations with the obtained recovery of more than 92 %. Linearity of the high performance liquid chromatography method with spectrophotometric detection was from 1.0 × 10−3 to 1.3 mg mL−1 (R2 = 0.998), with the limit of detection of 0.3 × 10−3 mg mL−1 for both enantiomers.