Biaryl-Bridged Macrocyclic Peptides: Conformational Constraint via Carbogenic Fusion of Natural Amino Acid Side Chains

A general method for constraining peptide conformations via linkage of aromatic sidechains has been developed. Macrocyclization of suitably functionalized tri-, tetra- and pentapeptides via Suzuki–Miyaura cross-coupling has been used to generate side chain to side chain, biaryl-bridged 14- to 21-membered macrocyclic peptides. Biaryl bridges possessing three different configurations, meta–meta, meta–ortho, and ortho–meta, were systematically explored through regiochemical variation of the aryl halide and aryl boronate coupling partners, allowing fine-tuning of the resultant macrocycle conformation. Suzuki–Miyaura macrocyclizations were successfully achieved both in solution and on solid phase for all three sizes of peptide. This approach constitutes a means of constraining peptide conformation via direct carbogenic fusion of side chains of naturally occurring amino acids such as phenylalanine and tyrosine, and so is complementary to strategies involving non-natural, for example, hydrocarbon, bridges

High-Throughput Capillary Liquid Chromatography Using a Droplet Injection and Application to Reaction Screening

The cycle time of a standard liquid chromatography (LC) system is the sum of the time for the chromatographic run and the autosampler injection sequence. Although LC separation times in the 1–10 s range have been demonstrated, injection sequences are commonly >15 s, limiting throughput possible with LC separations. Further, such separations are performed on relatively large bore columns requiring flow rates of ≥5 mL/min, thus generating large volumes of mobile phase waste when used for large scale screening and increasing the difficulty in interfacing to mass spectrometry. Here, a droplet injector system was established that replaces the autosampler with a four-port, two-position valve equipped with a 20 nL internal loop interfaced to a syringe pump and a three-axis positioner to withdraw sample droplets from a well plate. In the system, sample and immiscible fluid are pulled alternately from a well plate into a capillary and then through the injection valve. The valve is actuated when sample fills the loop to allow sequential injection of samples at high throughput. Capillary LC columns with 300 μm inner diameter were used to reduce the consumption of mobile phase and sample. The system achieved 96 separations of 20 nL droplet samples containing 3 components in as little as 8.1 min with 5-s cycle time. This system was coupled to a mass spectrometer through an electrospray ionization source for high-throughput chemical reaction screening

The Faculty of education restaurant consumers' attitude towards the responsible treatment of food

Food waste is a burning issue all over the world. Different producers, households, shops, restaurants, schools and other food offering venues face this problem. It is important to raise the society’s awareness about the consequences of food waste. In my diploma work I tried to establish the secondary school students and the students of the Faculty of Education attitude towards food and the level of their satisfaction with the faculty restaurant food. I have researched the reasons for the food waste and gathered students’ suggestions on how to reduce its amount. In my research, I have used a descriptive method and a quantitative approach. There were 60 students of the Faculty of Education and 59 secondary school students of the Pre-school Teacher Training Secondary School participating in my research. The research showed a moderate level of student’s satisfaction with the food in the restaurant at the Faculty of Education. The main reasons in case of dissatisfaction are according to students the taste and general food quality. I discovered that one of the main reasons for food waste are large portions but the students claimed the reason for not finishing the meal was the feeling of satiety. The secondary school students usually finish their meals whereas the college students more often leave some food on their plates. They have both suggested that food waste could be reduced by giving them smaller portions which means they should be able to choose the size of the meal at the self-service counter. They also proposed that users of food services could be educated about food waste problem through various lectures and education programs. They suggested the use of available food containers for the left-overs and extra food that could be given to those who are in need. Communication between the service providers and users is also very important as it can greatly reduce the number of times when less desired foods are offered. The awareness about discarded food is increasingly rising in schools and colleges. According to the results of my research, I estimated that secondary school students and college students are both conscious of the consequences of discarded food with college students being slightly more aware of the problem. My estimation is that the amount of food waste can be reduced by careful planning and management of offered foods. Different projects that would raise the awareness about food waste among the student population are also very important