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Antimicrobial Poly(2‐methyloxazoline)s with Bioswitchable Activity through Satellite Group Modification 下载免费PDF全文
Dipl.‐Ing. Christian Krumm Dipl.‐Chem. Simon Harmuth Montasser Hijazi Britta Neugebauer Anne‐Larissa Kampmann Helma Geltenpoth Prof. Dr. Albert Sickmann Prof. Dr. Joerg C. Tiller 《Angewandte Chemie (International ed. in English)》2014,53(15):3830-3834
Biocides are widely used for preventing the spread of microbial infections and fouling of materials. Since their use can build up microbial resistance and cause unpredictable long‐term environmental problems, new biocidal agents are required. In this study, we demonstrate a concept in which an antimicrobial polymer is deactivated by the cleavage of a single group. Following the satellite group approach, a biocidal quaternary ammonium group was linked through a poly(2‐methyloxazoline) to an ester satellite group. The polymer with an octyl‐3‐propionoate satellite group shows very good antimicrobial activity against Gram‐positive bacterial strains. The biocidal polymer was also found to have low hemotoxicity, resulting in a high HC50/MIC value of 120 for S. aureus. Cleaving the ester satellite group resulted in a 30‐fold decrease in antimicrobial activity, proving the concept valid. The satellite group could also be cleaved by lipase showing that the antimicrobial activity of the new biocidal polymers is indeed bioswitchable. 相似文献
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Maria Sdersten PhD Svante Granqvist Britta Hammarberg Annika Szabo 《Journal of voice》2002,16(3):356-371
Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices. 相似文献
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Dr. Patrick Rabe Jan Rinkel Britta Nubbemeyer Dr. Tobias G. Köllner Prof. Dr. Feng Chen Prof. Dr. Jeroen S. Dickschat 《Angewandte Chemie (International ed. in English)》2016,55(49):15420-15423
Genome sequences of social amoebae reveal the presence of terpene cyclases (TCs) in these organisms. Two TCs from Dictyostelium discoideum converted farnesyl diphosphate into (2S,3R,6S,9S)‐(?)‐protoillud‐7‐ene and (3S)‐(+)‐asterisca‐2(9),6‐diene. The enzyme mechanisms and EI‐MS fragmentations of the products were studied by labeling experiments. 相似文献
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Britta Lindholm-Sethson Josefina Nyström Martin Malmsten Lovisa Ringstad Andrew Nelson Paul Geladi 《Analytical and bioanalytical chemistry》2010,398(6):2341-2349
Electrochemical impedance spectroscopy plays an important role in biosensor science thanks to the possibility of finding specific
information from processes with different kinetics at a chosen electrode potential in one experiment. In this paper we briefly
discuss label-free impedimetric biosensors described in the literature. A novel method for neutral interpretation of impedance
data is presented that includes complex number chemometrics. Three examples are given based on impedance measurements on synthetic
biomembranes, in this case a lipid monolayer deposited on a mercury electrode. The interaction of various compounds with the
monomolecular lipid layer is illustrated with the following: (1) different concentrations of magainin (Geladi et al. in Proc. Int. Fed. Med. Biomed. Eng. 9:219–220, 2005); (2) different derivatives of gramicidin A (Lindholm-Sethson et al. in Langmuir 24:5029–5032, 2007), and (3) an antimicrobial peptide (Ringstad et al. in Langmuir 24:208–216, 2008). 相似文献