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Objective and Instrumental Methods for Evaluation of Hair Care Product Efficacy and Substantiation of Claims
Published in Dale H. Johnson, Hair and Hair Care, 2018
a. Hair Bulk and Resiliency. Yin et al. developed the Omega Loop Test (155) to measure the structural strength and resiliency of a hair mass. In this test, a hair tress held in the shape of the Greek letter omega was repeatedly compressed to a given strain and then allowed to recover. The differences between treatments were compared based on the average force and work values. The method by Garcia and Wolfram (156) used a special ring attachment on a universal tensile tester. They suspended a hair swatch from a tensile load cell and continuously recorded the forces required to pull the hair swatch through a Teflon ring. The work of passage through the ring measured the compressibility of a hair mass. Also, the successive passes of the swatch through the ring were used as a measure of resiliency or recovery from deformation of a hair mass. This sensitive method was claimed to quantify changes in the bulk properties of cosmetically treated hair (shampoos, hair sprays, conditioners, waving lotions, etc.).
Evaluation Methods for Conditioned Hair
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
on scalp, bending and torsional stiffness and resiliency of fibers, fiber diameter, fiber configuration, and fiber-fiber interactions. Only the second, fourth, and fifth parameters can be affected by cosmetic treatments, so it is not surprising that most of the simulated tests that have been developed are sensitive to these three parameters. Omega (\Omega) Loop Test
Multi-Functional Monoamine Oxidase and Cholinesterase Inhibitors for the Treatment of Alzheimer’s Disease
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Ireen Denya, Sarel F. Malan, Jacques Joubert
In the structure of BuChE, each monomer has a narrow 20 Å deep active site gorge lined by approximately 55 amino acid residues. The PAS is found at the mouth of the gorge with Asp 70 and Tyr 332 involved in the initial binding of positively charged substrates and in activation control. BuChE contains a hydrogen bond between these two residues which controls the functional design of the active site gorge. When a positively charged substrate is bound to the enzyme by a cation-π interaction with the aromatic ring of Tyr 332, the substrate interacts with the negatively charged Asp 70 and this process triggers a change in the conformation of the monomer. Thereafter the two flexible arms of the omega loop come close to each other and the substrate moves down to the Trp 82 residue of the choline-binding site. Trp 82 also forms a cationic-π complex with the substrate (Masson et al., 1997; Masson et al., 1999; Masson et al., 2001). The oxyanion hole, found near the choline-binding site, includes Gly 116, Gly 117 and Ala 199, helps to rotate the substrate to a position where it can be hydrolysed by Ser 198 (Ekholm and Konschin, 1999). When the substrate rotates horizontally, it binds to the acyl-binding pocket of the enzyme active site. Leu 286 and Val 288 are found in the acyl-binding pocket of BuChE (Phe 295 and Phe 297 in AChE) and allow for catalysis of larger acyl group containing substrates such as butyrylcholine (Radic et al., 1993). The stabilised substrate is hydrolysed by the catalytic triad, composed of Ser 198, His 438 and Glu 325, in the esteratic site of the active centre (Masson et al., 1997). It is important to note that six of the 14 aromatic amino acid residues lining the active site gorge of AChE are replaced by aliphatic residues in BuChE. This explains the larger volume of the BuChE active site gorge in comparison. The replacement is also responsible for selective sensitivity against different inhibitors of the enzymes (Saxena et al., 1999).
Compensatory intestinal antibody response against pro-inflammatory microbiota after bariatric surgery
Published in Gut Microbes, 2022
Torsten P.M. Scheithauer, Mark Davids, Maaike Winkelmeijer, Xanthe Verdoes, Ömrüm Aydin, Maurits de Brauw, Arnold van de Laar, Abraham S. Meijnikman, Victor E.A. Gerdes, Daniël van Raalte, Hilde Herrema, Max Nieuwdorp
This work was carried out on a subsample from the BARIA cohort (Amsterdam UMC and Spaarne Gasthuis, The Netherlands).9 The study protocols were approved by the Ethical Review Board of the Academic Medical Center, Amsterdam (approval code: NL55755.018.15), and all patients that have been included provided informed consent. In the present study, we included 20 obese individuals with Type 2 diabetes mellitus and 20 body-mass-index (BMI), sex and age matched controls. Individuals underwent RYGB (laparoscopic omega‐loop gastric bypass or laparoscopic sleeve gastrectomy). Samples were collected before RYGB surgery as well as a year after surgery. A 2-hour mixed meal test was performed after an overnight fast with two Nutridrinks compact 125 mL (Nutricia®) as described.9
Resolution of late-onset heart and liver failures after reversion of jejuno-ileal bypass: a case report
Published in Scandinavian Journal of Gastroenterology, 2018
Giovanna Pelà, Fabrizio De Rosa, Pierluigi Demola, Antonio Crocamo, Gabriele Missale, Stefano Cecchini, Federico Marchesi, Francesco Visioli, Enrico Maria Silini, Luigi Roncoroni
In February 2016, we performed a rehabilitation of the intestinal tract with reversion of JIB. A midline incision was carried out. After removal of multiple peritoneal adhesions, an omega loop with a side-to-side jejuno-ileal anastomosis was identified at 40 cm from the ileo-cecal valve, with signs of suture-ligation of the efferent jejunal limb. The previously defunctioned jejunal limb was observed to be partially re-opened, presenting slow peristalsis and dystrophic aspect. No signs of anti-reflux valves on the ileum were found. The anastomosis was then resected and two separated side-side jejuno-jejunal and ileo-ileal anastomoses were carried out in order to recover the normal bowel anatomy and physiology. There were no relevant postoperative complications.
Identification of new allosteric sites and modulators of AChE through computational and experimental tools
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Carlos Roca, Carlos Requena, Víctor Sebastián-Pérez, Sony Malhotra, Chris Radoux, Concepción Pérez, Ana Martinez, Juan Antonio Páez, Tom L. Blundell, Nuria E. Campillo
To verify these changes, we studied different areas of AChE along the MD trajectory using TRAPP software. The normal behaviour of the omega loop that corresponds to the opening of the side door is modified when the ligand is bound to the target. In the apo form a red area appears (new transient pocket) pointing out the opening of the side door, meanwhile this new transient pocket does not appear in the complex AChE-VP2.33 (Figure 10). This fact could suggest that compound VP2.33 could be able to modify the behaviour of the omega loop residues, as shown in the RMSF data in Figure S4.