9,955 research outputs found
ACCESS CONTROL USING WIRELESS FOR DATA COMMUNICATATION TO DATA TERMINAL
The main objective of this project is to develop wireless
access control that can be accessed via HTML website using Microchip development board. TCP/IP protocol is used for its wireless technology, using ZeroG module that provides 802.11 standards. Application of wireless access control starts with initialization of hardware and computer through IP address assigned by access point
Multicomponent Diels-Alder Sequences of 1-Aminodendralenes
This thesis explores the use of in situ generated acyclic
1-aminodendralenes in multicomponent diene-transmissive
Diels-Alder (DTDA) reaction sequences. Dendralenes have
previously been shown to generate polycyclic frameworks in a
step-economic manner. The 1-amino substituent is shown to promote
very high levels of site selectivity in these processes.
Chapter 1 reviews the Diels-Alder reactions of
1-amino-1,3-butadienes and is divided
into three sections. The first two sections cover the Diels-Alder
reactions of
1-amino-1,3-butadienes and 1-amino-3-siloxy-1,3-butadienes
(Rawal’s dienes)
generated with a stoichiometric amount of amine. The third
section covers
enantioselective Diels-Alder reactions involving
1-amino-1,3-butadienes generated in
situ with a catalytic amount of a chiral amine. While there have
been many reports of
Diels-Alder reactions of 1-amino-1,3-butadienes and
1-amino-3-siloxy-1,3-butadienes,
there has been only one involving a semi-cyclic
1-amino[3]dendralene. There have been
few examples which combine these Diels-Alder reactions with other
transformations in
multicomponent reactions to generate polycyclic frameworks.
Chapter 2 describes the use of acyclic 1-amino[3]dendralenes in
multicomponent
reactions to generate a diverse range of heterocyclic structures.
The condensation/Diels-
Alder reaction sequence was tolerant of a variety of amines as
well as carbon and
hereoatom-based dienophiles. The Diels-Alder reactions of
1-amino[3]dendralenes were
highly site-selective, taking place exclusively at the amine
substituted 1,3-butadiene
unit. The sequence was extended to a one-pot four-component
reaction by including an
additional dienophile for a Diels-Alder reaction to take place at
the newly generated
semi-cyclic diene. These condensation/Diels-Alder/Diels-Alder
cycloadducts were
generated with high diastereoselectivity, the origins of which
were investigated and
explained with the use of density functional theory calculations
(carried out by Prof
Paddon-Row). By reversing the order of events, that is performing
a Diels-Alder
reaction on the skipped dienal precursor before the
condensation/Diels-Alder reaction
sequence, constitutional isomers were accessed. The second
Diels-Alder reaction could be performed intramolecularly when an
amine bearing an alkenyl substituent was used. This
condensation/Diels-Alder/intramolecular Diels-Alder reaction
sequence furnished a variety of tricyclic and tetracyclic
heterocycles.
Chapter 3 describes the use of acyclic 1-aminodendralenes bearing
chiral amines in
organocatalytic, enantioselective Diels-Alder reactions to
deliver enantioenriched
cycloadducts. The enantioselective Diels-Alder reaction between
1-amino[3]dendralenes, the condensation product of skipped
dienals and chiral amines,
and various dienophiles followed by elimination of the amine
generated trienal
cycloadducts in good yield and high enantioselectivity. The
reaction tolerates
substitution on the skipped dienal as well as dienophiles
possessing an aldehyde
substituent at the α position. Extension of this methodology by
performing Wittig and Diels-Alder reactions on the trienal
cycloadducts enabled access to enantioenriched polycyclic
products. By using a diene-dialdehyde as the starting precursor,
it is anticipated that the Horeau principle would operate in the
twofold condensation/Diels-Alder/elimination reaction sequence
would furnish the cycloadduct in high enantioselectivity. A
preliminary attempt successfully generated the desired
cycloadduct as the major product
Defining the Cytoplasmic and Nuclear Transport of CPV Capsids in Cells
Canine parvovirus (CPV) is a non-enveloped virus that replicates in the nucleus during infection. While it is known that it uses the cell?s microtubule network to traverse the cytoplasm, the route of nuclear entry is unclear. The nuclear pore complex was thought to be used by the virus due to the presence of nuclear localization sequences (NLS) in the VP1 protein. But recent studies in the minute virus of mice (MVM) have proposed that it induces breaks in the nuclear envelop before entering the nucleus via these breaks. In this study, Crandell Feline Kidney (CRFK) cells stably transfected with GFP-lamin A/C were micro-injected with CPV capsids whose distribution within the cells was then detected using fluorescent-labeled antibodies. The CPV capsids did not appear to induce breaks in the nuclear lamin structure of the cells that was observed for the MVM
Visual Guided Approach-to-Grasp for Humanoid Robots
Vision based control for robots has been an active area of research for more than 30 years and significant progresses in the theory and application have been reported (Hutchinson et al., 1996; Kragic & Christensen, 2002; Chaumette & Hutchinson, 2006). Vision is a very important non-contact measurement method for robots. Especially in the field of humanoi
Regulation of morphogen signalling during neural patterning in the Xenopus embryo
Morphogens such as Hedghog, Wnt, FGF, and retinoic acid are important signals whose concentrations need to be tightly regulated in the vertebrate embryo to ensure body axis development and formation of the central nervous system. We first show that the intracellular cytoplasmic protein XSufu acts as a dual regulator of Hedgehog (Hh) and Wnt signals during neural induction and patterning in the Xenopus embryo. We further reveal an essential role of XSufu in the crosstalk of the two pathways, in which β-catenin activates Hh signalling upon overexpression of Gli1, and Gli inhibits Wnt signalling upon overexpression of β-catenin. A biphasic model for the role of XSufu in anteroposterior patterning of the neural plate is presented suggesting that XSufu suppresses anterior Gli and posterior β-catenin transcription factors in a dose-dependent manner. Then we introduce the secreted serine protease xHtrA1 as feedforward stimulator of long-range FGF signalling. Fibroblast growth factor (FGF) signals activate transcription of xHtrA1, and xHtrA1 stimulates FGF4 and FGF8 gene activities, allowing positive feedback regulation. We also show that xHtrA1 triggers proteolytic cleavage of xBiglycan, xSyndecan-4, and xGlypican-4, suggesting a model, in which xHtrA1 through cleaving proteoglycans releases FGF/proteoglycan complexes that act as long-range messages during anteroposterior patterning, mesoderm induction, and neuronal differentiation. Third, we present Xenopus retinol dehydrogenase-10 (XRDH10) as a critical enzyme for embryonic vitamin A metabolism and retinoic acid (RA) synthesis in the developing embryo. We show that XRDH10, which oxidizes vitamin A to retinal, is transcriptionally inhibited by RA, suggesting negative feedback regulation at the first step of RA biosynthesis. XRDH10 cooperates with XRALDH2, which further oxidizes retinal to bioactive RA, in Spemann’s organizer during dorsoventral patterning of the embryo. We also show that the nested gene expression and cooperate action of XRDH10 and XRALDH2 form a biosynthetic enzyme code that establishes RA gradients along the anteroposterior neuraxis
An Approach to Solving the Abstraction and Reasoning Corpus (ARC) Challenge
We utilise the power of Large Language Models (LLMs), in particular GPT4, to
be prompt engineered into performing an arbitrary task. Here, we give the model
some human priors via text, along with some typical procedures for solving the
ARC tasks, and ask it to generate the i) broad description of the input-output
relation, ii) detailed steps of the input-output mapping, iii) use the detailed
steps to perform manipulation on the test input and derive the test output. The
current GPT3.5/GPT4 prompt solves 2 out of 4 tested small ARC challenges (those
with small grids of 8x8 and below). With tweaks to the prompt to make it more
specific for the use case, it can solve more. We posit that when scaled to a
multi-agent system with usage of past memory and equipped with an image
interpretation tool via Visual Question Answering, we may actually be able to
solve the majority of the ARC challengeComment: 14 page
Evaluations and Modelling of Residual Stress of a joining- Sialon to Austenitic Stainless Steel
It is not easy to join ceramic to metal due to the differences in the coefficient of thermal
expansion of the two materials. The residual stress present has caused failure to the
joining. Materials with a relatively low elastic modulus can accommodate strain and will
tend to deform under the influence of this stress, while brittle materials such as glasses
and ceramics, will have a tendency to fracture. The evaluations and modelling of
residual stress of a joining-sialon to austenitic stainless steel was simulated using Finite
Element Analysis (ANSYS 1 0) software and simple analytical model was used to
evaluate the residual stress. The joining process was assumed as direct diffusion
bonding. The stress contour plot was discuss based on failure criteria. It is found that at
the area nearby the joining interface, stainless steel experiences tensil~ stress while
ceramic experiences compressive stress. The stress intensity is the highest at a few
points at the ceramic interface compared to the steel interface. Crack occurred at these
points due to the mismatch of thermal expansion and the inability of ceramic to
withstand the high concentration of tensile stress
Machine learning for outlier detection in medical imaging
Outlier detection is an important problem with diverse practical applications. In medical imaging, there are many diagnostic tasks that can be framed as outlier detection. Since pathologies can manifest in so many different ways, the goal is typically to learn from normal, healthy data and identify any deviations. Unfortunately, many outliers in the medical domain can be subtle and specific, making them difficult to detect without labelled examples. This thesis analyzes some of the nuances of medical data and the value of labels in this context. It goes on to propose several strategies for unsupervised learning. More specifically, these methods are designed to learn discriminative features from data of a single class. One approach uses divergent search to continually find different ways to partition the data and thereby accumulates a repertoire of features. The other proposed methods are based on a self-supervised task that distorts normal data to form a contrasting class. A network can then be trained to localize the irregularities and estimate the degree of foreign interference. This basic technique is further enhanced using advanced image editing to create more natural irregularities. Lastly, the same self-supervised task is repurposed for few-shot learning to create a framework for adaptive outlier detection. These proposed methods are able to outperform conventional strategies across a range of datasets including brain MRI, abdominal CT, chest X-ray, and fetal ultrasound data. In particular, these methods excel at detecting more subtle irregularities. This complements existing methods and aims to maximize benefit to clinicians by detecting fine-grained anomalies that can otherwise require intense scrutiny. Note that all approaches to outlier detection must accept some assumptions; these will affect which types of outliers can be detected. As such, these methods aim for broad generalization within the most medically relevant categories. Ultimately, the hope is to support clinicians and to focus their attention and efforts on the data that warrants further analysis.Open Acces
Empirical Analysis of Flow Characteristics in Physical Activity: Evidence from College Students in Shanghai
Chinese college students’ physical activity mainly consists of physical activity in physical education (PE) classes and extra-curriculum physical activity. With the improvement of college PE teaching, as well as the decline of college students’ physique and the frequent occurrence of psychological problems in college students, more and more Chinese colleges has started promoting students’ active participation in physical activity. This is performed as a means of improving the physique and the mental health of college students. Flow is a positive psychological experience that quite often takes place in physical activity. Based on the theory of flow, this paper investigates flow characteristics in physical activity of college students in Shanghai. Contributing to existing literature on flow, this paper focuses on empirically exploring the manifestation of flow characteristics, differences in flow characteristics in different types of sports, and differences in flow characteristics in different grades of college students in Shanghai. The data are collected from questionnaire survey. Questionnaire questions are based on the Flow State Scale of Jackson and Marsh (1994). A preliminary test was carried out to assess the effectiveness of questionnaire questions. According to test results, a minor amendment of questionnaire questions was made to ensure that all questionnaire questions can be effectively understood. 500 questionnaires are handed out, and all were successfully retrieved. Factor analysis is utilized to reduce dimension, i.e., factorizing the answers to 36 questions into 6 variables and in calculating the value of flow. Test results found that the manifestation of flow characteristics in physical activity of college students in Shanghai are “self-experience”, “integration of action and awareness”, “clear goals and feedback”, “lack of self-consciousness”, “sense of control”, and “time transformation”. There are sharp differences between flow characteristics in physical activity of different types of sports. The flow in closed motor skills physical activity is higher than that in open motor skills physical activity. The main differences are manifested through four factors: self-experience, integration of action and awareness, clear goals and feedback, and sense of control. There are also significant differences among flow characteristics of college students in different grades, with freshmen having the highest value of flow. The flow characteristics of students in different grades also differ in terms of different types of sports
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