Search results for "chemistry [Oligopeptides]"
showing 10 items of 211 documents
Application of model quality evaluation to systems biology
2008
Application of model quality evaluation to the quasispecies models is presented. These models are useful for the analysis of the DNA and RNA evolution and for the description of the population dynamics of viruses and bacteria. An estimate of the parameters together with their interval of variability is computed and the quality evaluation is tested on the basis of the model prediction error capability.
Twisting graphene nanoribbons into carbon nanotubes
2011
Although carbon nanotubes consist of honeycomb carbon, they have never been fabricated from graphene directly. Here, it is shown by quantum molecular-dynamics simulations and classical continuum-elasticity modeling, that graphene nanoribbons can, indeed, be transformed into carbon nanotubes by means of twisting. The chiralities of the tubes thus fabricated can be not only predicted but also externally controlled. This twisting route is an opportunity for nanofabrication, and is easily generalizable to ribbons made of other planar nanomaterials.
Resistencias, novedades y negociaciones : la terminología química durante la primera mitad del siglo XIX en España
2010
En este artículo se analiza la nueva terminología química en España durante la primera mitad del siglo XIX. Pretendemos mostrar que el estudio de la historia de la terminología permite conocer mejor los mecanismos de negociación, apropiación y resistencia de las comunidades locales, y ofrece nuevas claves para repensar las relaciones entre centro y periferias científicas. Las fuentes principales del estudio son los manuales de química publicados entre 1788 y 1845 en España. Estructuraremos la discusión en torno a cuatro temas que forman parte de las cuestiones generalmente analizadas en los estudios sobre la circulación del conocimiento: apropiaciones, controversias, novedades y resistencia…
Portable microwave assisted extraction: An original concept for green analytical chemistry.
2013
International audience; This paper describes a portable microwave assisted extraction apparatus (PMAE) for extraction of bioac-tive compounds especially essential oils and aromas directly in a crop or in a forest. The developed procedure, based on the concept of green analytical chemistry, is appropriate to obtain direct in-field information about the level of essential oils in natural samples and to illustrate green chemical lesson and research. The efficiency of this experiment was validated for the extraction of essential oil of rosemary directly in a crop and allows obtaining a quantitative information on the content of essential oil, which was similar to that obtained by conventional m…
Gold(I)-Catalyzed Intermolecular Cycloaddition of Allenamides with α,β-Unsaturated Hydrazones: Efficient Access to Highly Substituted Cyclobutanes
2014
α,β-Unsaturated N,N-dialkyl hydrazones undergo a mild [2 + 2] cycloaddition to allenamides when treated with a suitable gold catalyst. The method, which represents the first application of N,N-dialkyl hydrazones in gold catalysis, is compatible with a wide variety of substituents at the alkenyl moiety of the hydrazone component, proceeds with excellent levels of regio- and diastereoselectivity, and provides densely substituted cyclobutanes with good to excellent yields.
Jauno ķīmiķu skolas mācību satura sistematizēšana un izstrāde
2017
Jauno ķīmiķu skolas mācību satura sistematizēšana un izstrāde. Diča M., darba vadītājs Doc., Dr.ķīm. Logins J. Maģistra darbs, 64 lappuses, 8 attēli, 1 tabula, 23 literatūras avoti, 14 pielikumi. Latviešu valodā. Darba autore izpētījusi ārpusskolas darba organizēšanu ķīmijā, kā arī pedagoģiska un psiholoģiska rakstura zinātnisko literatūru, piedāvājot informāciju par ārpusskolas darba ķīmijas organizācijas formām, interaktīvām metodēm un ķīmijas eksperimenta nozīmi ķīmijas apguvē. Darba izstrādāti ieteikumi ārpusskolas nodarbībām un metodiskie materiāli Jauno ķīmiķu skolas nodarbībām, ko var izmantot ne tikai ārpusskolas pasākumos, bet arī mācību ārpusstundās ķīmijas apguvei.
A Polyphenylene Dendrimer Drug Transporter with Precisely Positioned Amphiphilic Surface Patches
2014
The design and synthesis of a polyphenylene dendrimer (PPD 3) with discrete binding sites for lipophilic guest molecules and characteristic surface patterns is presented. Its semi-rigidity in combination with a precise positioning of hydrophilic and hydrophobic groups at the periphery yields a refined architecture with lipophilic binding pockets that accommodate defined numbers of biologically relevant guest molecules such as fatty acids or the drug doxorubicin. The size, architecture, and surface textures allow to even penetrate brain endothelial cells that are a major component of the extremely tight blood-brain barrier. In addition, low to no toxicity is observed in in vivo studies using…
Sensitive determination of free benzophenone-3 in human urine samples based on an ionic liquid as extractant phase in single-drop microextraction pri…
2007
Abstract Benzophenone-3 (BZ3), one of the compounds most commonly used as UV filter in cosmetic products, can be absorbed through the skin into the human body, since it can be found at trace levels in urine from users of cosmetic products that contain BZ3. Moreover, different undesirable effects have been attributed to this compound. Thus, sensitive analytical methods to monitor urinary excretion of this compound should be developed. This paper presents a selective and sensitive methodology for BZ3 determination at ultratrace levels in human urine samples. The methodology is based on a novel microextraction technique, known as single-drop microextraction (SDME). An ionic liquid (IL) has bee…
Hybrid Chelator-Based PSMA Radiopharmaceuticals: Translational Approach
2021
(1) Background: Prostate-specific membrane antigen (PSMA) has been extensively studied in the last decade. It became a promising biological target in the diagnosis and therapy of PSMA-expressing cancer diseases. Although there are several radiolabeled PSMA inhibitors available, the search for new compounds with improved pharmacokinetic properties and simplified synthesis is still ongoing. In this study, we developed PSMA ligands with two different hybrid chelators and a modified linker. Both compounds have displayed a promising pharmacokinetic profile. (2) Methods: DATA5m.SA.KuE and AAZTA5.SA.KuE were synthesized. DATA5m.SA.KuE was labeled with gallium-68 and radiochemical yields of various…
Direct synthesis of C3-mono-functionalized oxindoles from N-unprotected 2-oxindole and their antileishmanial activity.
2014
A novel approach for the synthesis of unprecedented C3-mono-functionalized indolin-2-ones is reported, starting from 2-oxindole and chalcones. The reactions proceed regioselectively under mild conditions, without di- and tri-alkylated side products. The new compounds have been evaluated in vitro for their antiproliferative effects against the protozoan Leishmania infantum. Interestingly, they appear able to kill L. infantum promastigotes and amastigotes, without significant cytotoxic effects.