Direct reductive amination of camphor
Terpenoids are an irreplaceable class of natural products. The camphoryl group is an important moiety in the structure of chiral ligands for asymmetric synthesis catalysis or it can be used as an auxiliary group in asymmetric synthesis.[1] The usage of fenchone based molecules for asymmetric catalysis and synthesis is less common because of the difficulty of fenchone modifications due to steric hindrance. Camphor is a readily available starting molecule for the preparation of different compounds with biological activity. For example, camphor diimines demonstrate antiviral activity.[2] Fenchonyl amine-based molecules are potential therapeutic agents for the treatment of Alzheimer’s disease. Amines are a crucial class of organic compounds with multiple academic and industrial applications. There are a plethora of synthetic approaches towards amines synthesis and modifications, reductive amination being one of the most powerful and useful methods. However, the reductive amination of camphor and fenchone remains a challenge. A standard approach to reductive amination with amines other than ammonia and methylamine includes two steps: preparation of azomethines or Schiff bases in the presence of strong Lewis acids and their reduction with more or less conventional reducing agents. The synthesis of fenchonyl amines is even more challenging. There is no universal approach, and almost every manuscript reports some particular protocol different from others. In most cases, the first stage of this process requires quite harsh conditions. For example, the preparation of a Schiff base from camphor and 1-phenylethylamine requires 5-10 days of heating at 150°C.[3] Schiff bases of other primary amines could be prepared under similarly harsh conditions. Preparation of enamines is possible using titanium tetrachloride as a catalyst. The reduction also might be challenging. Sodium borohydride or sodium cyanoborohydride was described as suitable for this goal in several reports.[4] To the best of our knowledge, no papers describe any general approach for the direct reductive amination of camphor or fenchone. There is only one example of camphor direct reductive amination without an external hydrogen source using carbon monoxide as a reducing agent. This protocol is very efficient but its application is limited by the necessity of carbon monoxide and high-pressure equipment for the reaction setup.
A deep learning-based home safety perception system for household service robot
In 2016, the population of people over the age of 65 in Macau was 11.2%. This means that Macau has already become an aging society. As such, more younger generations are needed to look after the elderly. According to statistics, falls are the primary cause of injury or death for the elderly over 65 years old. About 30% of the elderly over 65 years old fall every year. Along with the increase in the elderly population, it is urgent to find a fast and effective way to ensure the safety of the elderly. As there is a lot more danger besides falling in an elderly life, we aim to build a robot collocated with its danger detection system to ensure the safety of the elderly at home. The reason we decided to use robots is that we want to have larger flexibility and mobility, for example, we can give elderly rescue materials when they need help. Moreover, more home robots will be used in the future, they can just apply our system to theirs and ensure the safety of elderlies. In this research, we mainly used cameras with the Openpose model to detect dangers such as falling, potential human action danger, and environmental danger. Innovative ways are used to detect fall action, collocated with our home robot, it is a foreseeing project that could ensure the safety of the elderly in a home environment.
Development of a rotor blade with optimized aerodynamics to propel a quadcopter
Sustainable mobility concepts are playing an increasingly important part in today's social developments. As a promising mode of future transportation, quadcopters play a special role, and their further development and optimization is being advanced along many disciplines. Even in my hometown of Zurich this trend has not passed by without leaving its marks. Since 2019, the Swiss National Postal Service has been testing autonomous means of transport together with the Zurich University Hospital as part of a pilot project. However, quadcopters are not exclusively used for transportation purposes. Geologists use them for landscape modeling and the insurance industry utilizes them for damage assessment. Quadcopters have also become an integral part of photography and agriculture, where they are used for pest control, for example [2]. I first became intensively involved with quadcopters in 2017, when I received a hobby model for my birthday in the form of the Mavic Pro from the Chinese company Da-Jiang Innovations Science and Technology Co., Ltd (DJI). In October of the same year, I completed an internship in the biofluid mechanics department of the Institute for ImplantTechnology and Biomaterials e.V., where I studied the aerodynamics of airfoils. With my Mavic Pro in my backpack, I had the idea to develop and prototype my own functional rotor for my quadcopter as part of my upcoming Swiss Matura thesis paper. The rotor would be considered functional if it generates enough lift to keep the quadcopter hovering. The focus of this project was the investigation of aerodynamic properties. The influence of other factors, such as the material used, was not the primary focus of the work and therefore not investigated in detail.
Design and Prototyping of a Low-Cost Ventilator for Rural Hospitals
This report includes the design and prototyping of a portable automatic bag-valve mask (BVM), or commonly known as the Ambu bag. This development is for use in emergency transport, resource-poor environments, and mass casualty cases like the COVID-19 pandemic. This device replaces the need for human operators whose job is to squeeze the BVMs for extended periods of time. The prototype is made from a stainless-steel skeleton, measuring 470 x 240 x 230 mm, with the addition of acrylic coverings. A repurposed motor from a car is used to drive the squeezing arm. The speed of the arm for inspiration and expiration along with the pausing time between each breath can be adjusted with this prototype. It also features an LCD screen to display the arm speed, along with real-time pressure graph displayed on both phones and computer monitors. For future versions, an app is to be developed to enable the control of the automatic bag-valve mask from phones and tablets, further creating ease for users and increasing portability. Additionally, important requirements will be added: alarm system for over pressurization, control for inspiration to expiration ratio, number of breaths per minute, control for tidal volume, pressure relief valve, and assist-control mode. The cost of this prototype is approximately $430. With this design of an automatic BVM, it allows for the production of a ventilator-like technology that will be able to perform main functions of basic ventilators at a fraction of the current cost.
Synthesis of Macro Porous Activated Carbon from Waste Polyethylene Terephthalate (PET) Bottles and Investigation of Usability in Dye Removal from Water Sources
Colorants are used in many industries, especially in the textile industry. These substances both cause visual pollution and create an anaerobic environment for aquatic creatures. In this study, it is aimed to examine the usability of activated carbon synthesized from waste polyethylene terephthalate (PET) bottles, which is an important environmental problem, in removing the pollution caused by the colorants caused by industrial activities in water resources.
Fabrication and Characterization of Biological Electrospinning Nanofiber Scaffold Based on Cellulose Diacetate-Gelatin-Green Tea for Tissue Engineering Applications
Tissue engineering has developed novel therapies such as many types of wound dressings, bio-pads, scaffolds and bandages, in order to reduce the effects of deep and extensive skin wounds. Here, we have produced an electrospun nanofiber scaffold, based on biodegradable materials such as gelatin (as a natural and hydrophilic polymer) and cellulose diacetate (with optimal biodegradability), in order to increase wound healing using nanotechnology. We also used green tea extract for its anti-oxidant and anti-bacterial effect, to improve the biological properties of the scaffold. In the fabrication process, two polymer solutions: 1. Gelatin (with acetic acid solvent) and 2. Cellulose Diacetate (with acetone solvent) mixed with green tea extract, were prepared. Then they were spun using a two-nozzle electrospinner to produce a hybrid nanofiber scaffold. SEM images showed enough finesse and uniformity of the produced scaffold to simulate the extracellular matrix. Further, measuring the contact angle of water droplet and the web surface, indicated optimal hydrophilicity of the nanofiber scaffold, which controls the level of scaffold degradability and cell adhesion. Also, the results of antibacterial tests for two bacterial strains (E. coli and S. aureus) showed the antibacterial characteristics of the extract-containing scaffold. In addition to previous tests, evaluation of fibroblast morphology on the nanofiber scaffolds, indicated appropriate cell adhesion and expansion, that confirms the biocompatibility of this produced scaffold.
Dependence of Alloy Composition in Color Change of Brass Foil by Oxide Thin Layer Formation
It is known that copper foil undergoes a color change in heating by oxide thin layer formation. Therefore, we focused on the color change by the oxidation of brass foil. Brass foil (Akaguchi (Cu87%Zn13% alloy) and Aoguchi (Cu85%Zn15% alloy)) also undergoes color change by oxidation, and it shows heating time and temperature dependence. Brass foil need longer heating time to appear color change than copper foil, and we can visually confirm that the brass has corrosion resistant. In addition, color change of brass foil depends on the percentage of copper in the brass, and Aoguchi shows rapidly color change in same heating condition. We show that brass has different physical properties than copper, even with a high percentage of copper in brass, and this was verified through comparison using diffusion length and RGB data in Aoguchi and Akaguchi. We demonstrate these colored brass foils are used as art materials, and our results expanded material using possibility of brass foil.