Mechanics and Mathematics in Ancient Greece

This entry presents an overview on how mechanics in Greece was linked to geometry. In ancient Greece, mechanics was about lifting heavy bodies, and mathematics almost coincided with geometry. Mathematics interconnected with mechanics at least from the 5th century BCE and became dominant in the Hellenistic period. The contributions by thinkers such as Aristotle, Euclid, and Archytas on fundamental problems such as that of the lever are sketched. This entry can be the starting point for a deeper investigation on the connections of the two disciplines through the ages until our present day.

Stefan Uroš II Milutin Nemanjić (1282–1321)

King Stefan Uroš II Milutin Nemanjić (1282—Donje Nerodimlje, October 29, 1321) was a Serbian medieval king, the seventh ruler of the Serbian Nemanide dynasty, the son of King Stefan Uroš I (r. 1243–1276) and Queen Helen Nemanjić (see), the brother of the King Stefan Dragutin (r. 1276–1282) and the father of King Stefan Dečanski (r. 1322–1331). Together with his great grandfather Stefan Nemanja, the founder of the Nemanide dynasty, and his grandson, Emperor Stefan Uroš IV Dušan, King Milutin is considered the most powerful ruler of the Nemanide dynasty. The long and successful military breach of King Milutin, down the Vardar River Valley and deep into the Byzantine territories, represents the beginning of Serbian expansion into southeastern Europe, making it the dominant political power in the Balkan region in the 14th century. During that period, Serbian economic power grew rapidly, mostly because of the development of trading and mining. King Milutin founded Novo Brdo, an internationally important silver mining site. He started minting his own money, producing imitations of Venetian coins (grosso), which gradually diminished in value. This led to the ban of these coins by the Republic of Venice and provided King Milutin a place in Dante’s Divina Commedia. King Milutin had a specific philoktesia fervor: He built or renovated over three dozen Serbian Orthodox churches and monasteries not only in Serbia but also in Thessaloniki, Mt. Athos, Constantinople and The Holy Land. Over fifteen of his portraits can be found in the monumental painting ensembles of Serbian medieval monasteries as well as on two icons.

Asymptomatic Patients and Immune Subjects

An asymptomatic patient is someone who contracts a disease but shows no symptoms. An immune subject is a person who is free from virus infection. Both of these categories of people experience the limitations of government imposed by a pandemic situation, with one important difference. Probably only the first subjects contribute, in spite of themselves, to the spread of the disease and to the contagion of the people most susceptible to the virus. This implies that their detection is essential to limit infections. Therefore, knowing the characteristics of these people and those immune to the virus can be extremely useful in mitigating the effects of the disease and/or defeating it.

Molecular Aspects of Spike–ACE2 Interaction

A new betacoronavirus (CoV-2) is responsible for the pandemic of severe acute respiratory syndrome (SARS) that began in China at the end of 2019, today known as COronaVIrus Disease 2019 (COVID-19). Subsequent studies confirmed the human angiotensin-converting enzyme 2 (hACE2) as the main cell receptor of spike trimeric glycoprotein, located on the viral envelope, mediating the CoV-2 invasion into the host cells through the receptor-binding domain (RBD) of the spike. Computational analysis of the known experimental 3D structures of spike–ACE2 complexes evidenced distinguishing features in the molecular interactions at the RBD-cell receptor binding interface between CoV-2 and previous CoV-1. The spike represents a key target for drug design as well as an optimal antigen for RNA/viral vector vaccines and monoclonal antibodies in order to maximize prevention and therapy of COVID-19.

Aircraft Icing Severity Evaluation

Aircraft icing refers to the ice buildup on the surface of an aircraft flying in icing conditions. The ice accretion on the aircraft alters the original aerodynamic configuration and degrades the aerodynamic performances and may lead to unsafe flight conditions. Evaluating the flow structure, icing mechanism and consequences is of great importance to the development of an anti/deicing technique. Studies have shown computational fluid dynamics (CFD) and machine learning (ML) to be effective in predicting the ice shape and icing severity under different flight conditions. CFD solves a set of partial differential equations to obtain the air flow fields, water droplets trajectories and ice shape. ML is a branch of artificial intelligence and, based on the data, the self-improved computer algorithms can be effective in finding the nonlinear mapping relationship between the input flight conditions and the output aircraft icing severity features.

Prefabricated Building Systems—Design and Construction

Modern Methods of Construction with Offsite Manufacturing is an advancement from prefabricated technologies that existed for decades in the construction industry, and is a platform to integrate various disciplines into providing a more holistic solution. Due to the rapid speed of construction, reduced requirement of labour and minimised work on site, offsite manufacturing and prefabricated building systems are becoming more popular, and perhaps a necessity for the future of the global construction industry. The approach to the design and construction of prefab building systems demands a thorough understanding of their unique characteristics.

Opportunities for Catalytic Reactions and Materials in Buildings

Residential and commercial buildings are responsible for over 30% of global final energy consumption and accounts for ~40% of annual direct and indirect greenhouse gas emissions. Energy efficient and sustainable technologies are necessary to not only lower the energy footprint but also lower the environmental burden. Many proven and emerging technologies are being pursued to meet the ever-increasing energy demand. Catalytic science has a significant new role to play in helping address sustainable energy challenges, particularly in buildings, compared to transportation and industrial sectors. Thermally driven heat pumps, dehumidification, cogeneration, thermal energy storage, carbon capture and utilization, emissions suppression, waste-to-energy conversion, and corrosion prevention technologies can tap into the advantages of catalytic science in realizing the full potential of such approaches, quickly, efficiently, and reliably. Catalysts can help increase energy conversion efficiency in building related technologies but must utilize low cost, easily available and easy-to-manufacture materials for large scale deployment. This entry presents a comprehensive overview of the impact of each building technology area on energy demand and environmental burden, state-of-the-art of catalytic solutions, research, and development opportunities for catalysis in building technologies, while identifying requirements, opportunities, and challenges.

Helen Nemanjić (?–1314)

Queen Helen Nemanjić (?–Brnjaci near Zubin Potok, February 8, 1314) was a Serbian medieval queen and consort of King Stefan Uroš I (r. 1243–1276), the fifth ruler of the Serbian Nemanide dynasty. She was the mother of the kings Stefan Dragutin and Stefan Uroš II Milutin. Today, she is known as Helen of Anjou (Jelena Anžujska in Serbian) although her real name was most probably Heleni Angelina (Ελένη Aγγελίνα). She was the founder of the Serbian Orthodox monastery of Gradac as well as four Franciscan abbeys in Kotor, Bar, Ulcinj, and Shkodër. Together with her sons, Kings Stefan Dragutin and Stefan Uroš II Milutin she helpedrenovation of Benedictine abbey of Sts. Sergius and Bacchus near Shkodër on Boyana river in present-day Albania. After the death of her husband, she ruled Zeta and Travunija until 1306. She was known for her religious tolerance and charitable and educational endeavors. She was elevated to sainthood by the Serbian Orthodox Church. Along with Empress Helen, the wife of Serbian Emperor Stefan Uroš IV Dušan, Queen Helen was the most frequently painted woman of Serbian medieval art. Six of her portraits can be found in the monumental painting ensembles of the Serbian medieval monasteries of Sopoćani, Gradac, Arilje, Đurđevi Stupovi (Pillars of St. George), and Gračanica, as well as on two icons and one seal. Queen Helen is also the only female Serbian medieval ruler whose vita was included in the famous collection of the “Lives of Serbian Kings and Archbishops” by Archbishop Danilo II, a prominent church leader, warrior, and writer.

Limbic Encephalitis Associated with COVID-19

Limbic encephalitis (LE) is an inflammatory disease of the brain, in which lesion is anatomically limited in structures of the limbic system. In some cases, LE can start with symptoms of limbic dysfunction with further involvement of other regions of the brain. Classic LE syndrome includes such symptoms as the development of personality disorders, depression, sleep disorders, epileptic seizures, hallucinations and cognitive disorders (short-term and long-term memory impairment). The information of clinical examination, electroencephalogram (EEG), magnetic resonance imaging (MRI) and cerebrospinal fluid studies (CSF) suggest the diagnosis of LE in most patients with Coronavirus Disease 2019 (COVID-19).

Fungal Secondary Metabolism

Fungal secondary metabolites (SMs) comprise a vast collection of compounds expendable for these organisms under laboratory conditions. They exhibit enormous chemical diversity, and usually belong to four major families: terpenoids, polyketides, non-ribosomal peptides, or a combination of the last two. Their functions are very diverse and are normally associated with a greater fitness of the producing fungi in their environment, which often compete with other microorganisms or interact with host plants. Many SMs have beneficial applications, e.g., as antibiotics or medical drugs, but others, known as mycotoxins, are harmful to health.