Cat

The cat (Felis catus) is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of the family. Cats are commonly kept as house pets but can also be farm cats or feral cats; the feral cat ranges freely and avoids human contact. Domestic cats are valued by humans for companionship and their ability to kill vermin. About 60 cat breeds are recognized by various cat registries. The cat is similar in anatomy to the other felid species: it has a strong flexible body, quick reflexes, sharp teeth, and retractable claws adapted to killing small prey like mice and rats. Its night vision and sense of smell are well developed. Cat communication includes vocalizations like meowing, purring, trilling, hissing, growling, and grunting as well as cat-specific body language. Although the cat is a social species, it is a solitary hunter. As a predator,

Novel Ionic Liquids For Electrochemical Applications

Pui Shan Genevieve Lau

This thesis is organized into three main sections, and is concerned with the design and synthesis of novel ionic liquids (ILs), and their associated electrochemical applications. In the first section, a general introduction to the field of ionic liquids is presented, followed by the synthesis and characterization details of all novel compounds used in the study. The second section summarizes work done on the development of more stable dye-sensitized solar cells (DSCs). An introduction to the field of photovoltaics and DSCs is first delivered in Chapter 3, which is followed by two chapters of original work on ionic liqiud-based electrolytes for DSC applications. In Chapter 4, it is shown that novel triazolium-based ionic liquids can be used to fabricate dye-sensitized solar cells, giving power conversion efficiencies of up to 6.00 %. The ionic liquid-based electrolytes are found to be compatible with a range of organic and inorganic photosensitizers, although the ruthenium-based dye (coded C106) exhibits the best performance. A device employing one of these newly-developed electrolytes is also shown to be very stable, retaining ca. 90% of its initial performance even after 1000 hours of continuous full sun illumination at 60 âŠC. In Chapter 5, we focus on the development of stable porphyrin-sensitized solar cells, using IL-based electrolytes. Our studies reveal that the long-term stability of porphyrin-based DSCs are highly dependent on additives in the electrolyte. In particular, it is found that the additive, guanidinium thiocyanate, is essential for the preparation of long-lived devices. It is also shown that the beneficial effect of this additive originates from the thiocyanate anion, rather than the guanidinium cation. The third section of this thesis deals with the ionic liquid-catalyzed electroï¿Œchemical reduction of carbon dioxide. Following a general introduction on carbon dioxide mitigation using ionic liquids (Chapter 6), the results of our work in this area are presented in Chapter 7. Our studies reveal that not all ionic liquids are stable at the potentials required for CO2 reduction. However, the imidazolium-based salts generally perform quite well. The catalytic effect of the IL is found to mainly stem from the cation, with the anion playing a somewhat secondary role. Our results also demonstrate that substitutions on the imidazolium ring can have a huge impact on catalysis. Product analysis shows that the best-performing catalyst produces carbon monoxide as the dominant product, with Faradaic efficiencies of between 70 to 80 %.

EPFL2015

A scalable CRISPR/Cas9-based fluorescent reporter assay to study DNA double-strand break repair choice

Stephanie Jocelyne Sungalee

Double-strand breaks (DSBs) are the most toxic type of DNA lesions. Cells repair these lesions using either end protection- or end resection-coupled mechanisms. To study DSB repair choice, we present the Color Assay Tracing-Repair (CAT-R) to simultaneously quantify DSB repair via end protection and end resection pathways. CAT-R introduces DSBs using CRISPR/Cas9 in a tandem fluorescent reporter, whose repair distinguishes small insertions/deletions from large deletions. We demonstrate CAT-R applications in chemical and genetic screens. First, we evaluate 21 compounds currently in clinical trials which target the DNA damage response. Second, we examine how 417 factors involved in DNA damage response influence the choice between end protection and end resection. Finally, we show that impairing nucleotide excision repair favors error-free repair, providing an alternative way for improving CRISPR/Cas9-based knock-ins. CAT-R is a high-throughput, versatile assay to assess DSB repair choice, which facilitates comprehensive studies of DNA repair and drug efficiency testing. Cells employ different repair pathways to repair DNA double strand breaks. Here, the authors develop a CRISPR/Cas9-dependent method to study choices in DNA repair called the Color Assay Tracing-Repair (CAT-R) which simultaneously measure outcomes of DSB repair via end-protection and end-resection pathways.

2020

Novel Ionic Liquids For Electrochemical Applications

Pui Shan Genevieve Lau

EPFL2015

Schrödinger's cat : open the EPFL Library box

Novel Ionic Liquids For Electrochemical Applications

A scalable CRISPR/Cas9-based fluorescent reporter assay to study DNA double-strand break repair choice

Novel Ionic Liquids For Electrochemical Applications

A scalable CRISPR/Cas9-based fluorescent reporter assay to study DNA double-strand break repair choice

Schrödinger's cat : open the EPFL Library box