690 research outputs found
Identification of SNPs Potentially Associated with Asthma Using a Di-isocyanate Luciferase Reporter Assay
Occupational Asthma (OA) is a common lung disorder that can be caused or aggravated by exposures and conditions in the work places. Di-isocyanate asthma (DA) is one type of OA. Despite years of research, there are no reliable markers to predict risk or susceptibility for DA. Previous studies have identified 23 candidate single nucleotide polymorphisms (SNPs) that are potentially associated with genes that are related with DA. In this study, we tested the functional relevance of the 23 candidate SNPs (mostly intronic) in several DA-related genes. We hypothesized that some of these SNPs may affect the binding of relevant transcription factors, causing altered expression of these genes. We inserted short DNA fragments (~30 bp) containing the SNPs and long DNA fragments containing multiple SNPs into the pGL3-promoter firefly luciferase reporter vector and transfected them into adenocarcinomas human alveolar basal epithelial cells (A549 cell line). The expression levels of different SNP constructs were measured by luciferase reporter assay. Our results showed that 3 SNPs (rs11571537, rs2287231 and rs2446824) that are located in ATF3, TAR1 and CDH17 genes, respectively, had significant difference in luciferase activities between risk and non-risk alleles (C vs. T for rs11571537, A vs. G for rs2287231, and T vs. C for rs2446824). Our data indicate that the SNPs we found may affect the expression of ATF3, TAR1 and CDH17 genes, which may play important roles in the development of the DA
Improving Microbial Safety of Food Products by Thermal and Non-thermal technology and Evaluate the Knowledge of Antibiotic Resistant Issue Among Local Produce Growers
Microbial contamination of food products is one of the main transmission routes of disease in the world today, which is responsible for about two-thirds of all food-borne disease outbreaks although the hygiene process was improved recently. Improving microbial safety and implementing a good food management system are important elements to reduce microbial contamination and improve food safety and security. To improve microbial safety, I conducted inactivation studies on food pathogens and further explored antibiotic resistant risks. Initial research evaluated the efficacy of commercial antimicrobials distribution by comparing electrostatic sprayer with conventional sanitization process. The antibiotics applied by electrostatic spraying achieved significant additional reductions on the foodborne pathogen and more economically feasible compare to the conventional spraying method. Further exploration was carried out building inactivation model analysis on foodborne pathogens under thermal dynamic conditions. Thermal kinetics of foodborne pathogen on moisture enhanced meat were determined and a potential surrogate of Salmonella was identified. Finally, an investigation of the knowledge and attitude of antibiotic resistant issues among local food processors was conducted and results provided suggestions regarding antibiotic risks for local government agencies policy improvement. These studies combined to identify and improve microbial safety on food products by using technologies and statistical analysis
Wireless communication using ultrasound in air with parallel OOK channels
The use of airborne ultrasonic transducers for wireless communication was demonstrated. The work used capacitive ultrasonic transducers to transmit coded binary signals through parallel air channels. On-Off Keying modulation was successfully implemented in the system. Within the limited bandwidth of the transducers, six channels were used at frequencies from 50 kHz to 110 kHz with a channel spacing of 12 kHz, allowing 8-bit packets to be transmitted simultaneously. Wireless handshaking was achieved using a simple synchronization signal in front of the information signal. A data rate of 60 kbps was achieved over a short distance and the system Bit Error Rate (BER) was analysed
Multichannel ultrasonic data communications in air using range-dependent modulation schemes
There are several well-developed technologies of wireless communication such as radio frequency (RF) and infrared (IR), but ultrasonic methods can be a good alternative in some situations. A multichannel airborne ultrasonic data communication system is described in this paper. ON-OFF keying (OOK) and binary phase-shift keying (BPSK) modulation schemes were implemented successfully in the system by using a pair of commercially available capacitive ultrasonic transducers in a relatively low multipath indoor laboratory environment. Six channels were used from 50 to 110 kHz with a channel spacing of 12 kHz, allowing multiple 8-bit data packets to be transmitted simultaneously. The system data transfer rate achieved was up to 60 kb/s and ultrasonic wireless synchronization was implemented instead of using a hard-wired link. A model developed in the work could accurately predict ultrasonic signals through the air channels. Signal root mean square (rms) values and system bit error rates (BERs) were analyzed over different distances. Error-free decoding was achieved over ranges up to 5 m using a multichannel OOK modulation scheme. To obtain the highest data transfer rate and the longest error-free transmission distance, a range-dependent multichannel scheme with variable data rates, channel frequencies, and different modulation schemes, was also studied in the work. Within 2 m, error-free transmission was achieved using a five-channel OOK with a data rate of 63 kb/s. Between 2 and 5 m, six-channel OOK with 60 kb/s data transfer rate was error free. Beyond 5 m, the error-free transmission range could be extended up to 10 m using three-channel BPSK with a reduced data rate of 30 kb/s. The situation when two transducers were misaligned using three-channel OOK and BPSK schemes was also investigated in the work. It was concluded that error-free transmission could still be achieved with a lateral displacement of less than 7% and oblique angles of less than 7°, and three-channel BPSK proved to be more robust than three-channel OOK with transducer misalignment
Progress in airborne ultrasonic data communications for indoor applications
Capacitive ultrasonic transducers are efficient transmitters and receivers for ultrasonic waves in air, making them ideal devices for signal transmissions in air. Ultrasonic signals are unregulated, difficult to intercept from outside the room, and interference free to most electronic devices. These high security features make ultrasonic communication systems an alternative to radio frequency (RF) based systems for indoor applications. This paper investigated a prototype ultrasonic communication system using a pair of commercially available capacitive ultrasonic transducers in an indoor laboratory environment. Multichannel On-OFF keying (OOK) and binary phase-shift keying (BPSK) modulation schemes were implemented successfully in the system with wireless synchronization, achieving an overall data rate of 60 kb/s using ultrasonic bands from 50 to 110 kHz. The results show that a reliable line-of-sight (LOS) link can be established for communications over distances of 10 and 11 m using multichannel OOK and BPSK, respectively
DEVELOPMENT OF ION MASS SPECTROMETRY-BASED INSTRUMENTATION AND APPLICATIONS
Ion mobility spectrometry (IMS) is a technique that can rapidly separate ions based on their mobility in an inert buffer gas and provide insights to molecular structure. When coupled with mass spectrometry (MS), IM-MS offers a powerful hybrid analytical technique that has many biological, pharmaceutical, structural, environmental and other applications. During past decades, various types of IM-MS instruments have been built and applied, of which the most popular type is IMS-time of flight (TOF) MS. However, there are biological problems which require resolution higher than TOFMS can provide. The goal of my first project was to build a drift time IMS (DTIMS) and couple it with a commercial linear ion trap (LTQ) mass analyzer which can provide not only quick separation but also mass analysis capability. It can be used for analysis of complex biochemical samples and degradation mixtures for example. Furthermore, the IMS will be subsequently transferred to a LTQ Orbitrap-Velos MS to obtain mass data with high resolution and accuracy.
The second project focuses on the analysis of carbon nanotube (CNT) and graphene oxide (GO) degradation products using MS. In recent years different methods for carbon nanomaterial deg-radation have been developed and it is of interest to gain better understanding of the degradation process. MS is a suitable analysis method for the detection of intermediate mixtures with mole-cules of different molecular weight size. The objective of this project was to use MS and tandem MS data combined with other analytical techniques (e.g. nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR)) in order to identify and determine the structures of intermediate degradation products of CNT and GO, and understand degradation mechanisms
Airborne ultrasonic communications using multiple parallel channels
Concerns still exist over the safety of prolonged exposure to radio frequency (RF) wireless transmissions and there are also potential data security issues due to remote signal interception. Airborne ultrasound may be used as an alternative to RF for indoor wireless communication systems for securely transmitting data over parallel channels at short ranges. This thesis describes the design and evaluation of an airborne ultrasonic communication system using capacitive transducers. In this study, basic digital modulation schemes, such as ON-OFF keying (OOK) and binary phase-shift keying (BPSK), were implemented successfully over multiple parallel channels for data transmission over an air gap of up to 10 m with wireless synchronization using ultrasonic means. A simulation model that can precisely predict ultrasonic signals through the air channel was also created to help with signal characterisation. To further improve the bandwidth efficiency and eliminate the need for filtering, quadrature amplitude modulation (QAM) using orthogonal frequency division multiplexing (OFDM) method was investigated. The recorded data rate was 800 kb/s at 0.7 m with no measurable errors using prototype broadband ultrasonic transducers, and 180 kb/s at 6 m using relatively narrowband commercially available transducers. This thesis has also looked at implementing an indoor communication network with ceiling-mounted base stations and a mobile communicator for practical applications. An asynchronous ultrasonic location technique using Gold Code modulated ranging signals was chosen to optimise the modulation schemes, and offer automatic handover between different cell regions on a switch on and off basis as all base stations use the same frequency bands for data transmission
The localization of single pulse in VLBI observation
In our previous work, we propose a cross spectrum based method to extract
single pulse signals from RFI contaminated data, which is originated from
geodetic VLBI postprocessing. This method fully utilizes fringe phase
information of the cross spectrum and hence maximizes signal power, however the
localization was not discussed in that work yet. As the continuation of that
work, in this paper, we further study how to localize single pulses using
astrometric solving method. Assuming that the burst is a point source, we
derive the burst position by solving a set of linear equations given the
relation between residual delay and offset to a priori position. We find that
the single pulse localization results given by both astrometric solving and
radio imaging are consistent within 3 sigma level. Therefore we claim that it
is possible to derive the position of a single pulse with reasonable precision
based on only 3 or even 2 baselines with 4 milliseconds integration. The
combination of cross spectrum based detection and the localization proposed in
this work then provide a thorough solution for searching single pulse in VLBI
observation. According to our calculation, our pipeline gives comparable
accuracy as radio imaging pipeline. Moreover, the computational cost of our
pipeline is much smaller, which makes it more practical for FRB search in
regular VLBI observation. The pipeline is now publicly available and we name it
as "VOLKS", which is the acronym of "VLBI Observation for frb Localization Keen
Searcher".Comment: 11 pages, 4 figures, 3 tables, accepted for publication in A
How to represent paintings: a painting classification using artistic comments
The goal of large-scale automatic paintings analysis is to classify and retrieve images using machine learning techniques. The traditional methods use computer vision techniques on paintings to enable computers to represent the art content. In this work, we propose using a graph convolutional network and artistic comments rather than the painting color to classify type, school, timeframe and author of the paintings by implementing natural language processing (NLP) techniques. First, we build a single artistic comment graph based on co-occurrence relations and document word relations and then train an art graph convolutional network (ArtGCN) on the entire corpus. The nodes, which include the words and documents in the topological graph are initialized using a one-hot representation; then, the embeddings are learned jointly for both words and documents, supervised by the known-class training labels of the paintings. Through extensive experiments on different classification tasks using different input sources, we demonstrate that the proposed methods achieve state-of-art performance. In addition, ArtGCN can learn word and painting embeddings, and we find that they have a major role in describing the labels and retrieval paintings, respectively
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