125 research outputs found
CMOS-Integrated Film Bulk Acoustic Resonators for Label-Free Biosensing
The throughput is an important parameter for label-free biosensors. Acoustic resonators like the quartz crystal microbalance have a low throughput because the number of sensors which can be used at the same time is limited. Here we present an array of 64 CMOS-integrated film bulk acoustic resonators. We compare the performance with surface plasmon resonance and the quartz crystal microbalance and demonstrate the performance of the sensor for multiplexed detection of DNA
Experimental hydrophilic vinyl polysiloxane (VPS) impression materials incorporating a novel surfactant compared with commercial VPS
This PhD was partially funded by National University of Sciences & Technology (NUST), Islamabad, Pakistan, and therefore we thank the authorities at NUST
Extravasation of leukocytes in comparison to tumor cells
The multi-step process of the emigration of cells from the blood stream through the vascular endothelium into the tissue has been termed extravasation. The extravasation of leukocytes is fairly well characterized down to the molecular level, and has been reviewed in several aspects. Comparatively little is known about the extravasation of tumor cells, which is part of the hematogenic metastasis formation. Although the steps of the process are basically the same in leukocytes and tumor cells, i.e. rolling, adhesion, transmigration (diapedesis), the molecules that are involved are different. A further important difference is that leukocyte interaction with the endothelium changes the endothelial integrity only temporarily, whereas tumor cell interaction leads to an irreversible damage of the endothelial architecture. Moreover, tumor cells utilize leukocytes for their extravasation as linkers to the endothelium. Thus, metastasis formation is indirectly susceptible to localization signals that are literally specific for the immune system. We herein compare the extravasation of leukocytes and tumor cells with regard to the involved receptors and the localization signals that direct the cells to certain organs and sites of the body
Viral metagenomics demonstrates that domestic pigs are a potential reservoir for Ndumu virus
BACKGROUND: The rising demand for pork has resulted in a massive expansion of pig production in Uganda. This has resulted in increased contact between humans and pigs. Pigs can act as reservoirs for emerging infectious diseases. Therefore identification of potential zoonotic pathogens is important for public health surveillance. In this study, during a routine general surveillance for African swine fever, domestic pigs from Uganda were screened for the presence of RNA and DNA viruses using a high-throughput pyrosequencing method. FINDINGS: Serum samples from 16 domestic pigs were collected from five regions in Uganda and pooled accordingly. Genomic DNA and RNA were extracted and sequenced on the 454 GS-FLX platform. Among the sequences assigned to a taxon, 53% mapped to the domestic pig (Sus scrofa). African swine fever virus, Torque teno viruses (TTVs), and porcine endogenous retroviruses were identified. Interestingly, two pools (B and C) of RNA origin had sequences that showed 98% sequence identity to Ndumu virus (NDUV). None of the reads had identity to the class Insecta indicating that these sequences were unlikely to result from contamination with mosquito nucleic acids. CONCLUSIONS: This is the first report of the domestic pig as a vertebrate host for Ndumu virus. NDUV had been previously isolated only from culicine mosquitoes. NDUV therefore represents a potential zoonotic pathogen, particularly given the increasing risk of human-livestock-mosquito contact
The genomes of three stocks comprising the most widely utilized live sporozoite Theileria parva vaccine exhibit very different degrees and patterns of sequence divergence
Disorders of sex development: effect of molecular diagnostics
Disorders of sex development (DSDs) are a diverse group of conditions that can be challenging to diagnose accurately using standard phenotypic and biochemical approaches. Obtaining a specific diagnosis can be important for identifying potentially life-threatening associated disorders, as well as providing information to guide parents in deciding on the most appropriate management for their child. Within the past 5 years, advances in molecular methodologies have helped to identify several novel causes of DSDs; molecular tests to aid diagnosis and genetic counselling have now been adopted into clinical practice. Occasionally, genetic profiling of embryos prior to implantation as an adjunct to assisted reproduction, prenatal diagnosis of at-risk pregnancies and confirmatory testing of positive results found during newborn biochemical screening are performed. Of the available genetic tests, the candidate gene approach is the most popular. New high-throughput DNA analysis could enable a genetic diagnosis to be made when the aetiology is unknown or many differential diagnoses are possible. Nonetheless, concerns exist about the use of genetic tests. For instance, a diagnosis is not always possible even using new molecular approaches (which can be worrying for the parents) and incidental information obtained during the test might cause anxiety. Careful selection of the genetic test indicated for each condition remains important for good clinical practice. The purpose of this Review is to describe advances in molecular biological techniques for diagnosing DSDs
Piezoelectric and ferroelectric device technologies for microwave oscillators
The purpose of this thesis is to investigate piezoelectric and ferroelectric thin film device technologies for application in microwave oscillators.Thin film varactors based on ferroelectric materials are considered. Experimental development of practical varactors based on paraelectric phase BaxSr1−xTiO3, in terms of layout design and model extraction, is presented in the thesis. Experimental results of voltage-controlled oscillators based on ferroelectric varactors operating at 16 GHz and 19 GHz are also presented. The ferroelectric device technology is furthermore compared to traditional varactor technologies, and discussed from the perspectiveof oscillator applications.Thin film bulk acoustic resonators based on piezoelectric materials and biased electrostrictive materials are considered. Specifically, fixed-frequency resonators based on AlN and tunable resonators based on paraelectric phase BaxSr1−xTiO3 are investigated in the thesis. An integration concept is developed for AlN resonators, and experimentally demonstrated by 2 GHz oscillators. Additionally, modelling and measurement techniques for resonators based on AlN and BaxSr1−xTiO3 are developed. The investigated technologies are compared to traditional planar resonator technologies
Bioinformatic methods for metagenomics and comparative genetics in veterinary medicine
Good science includes innovation, investigation, and rigor. This thesis’ first study is related to rigor. This study was performed at the International Livestock Research Institute (ILRI) in Nairobi, as part of the Arbovirus Incidence and Diversity (AVID) project. A field sample recording system was developed, which saves time and location metadata from the global positioning system (GPS), as well as a connected system monitoring the biobank, freezer, incubators and servers. This monitoring system more than once prevented loss of resources due to freezer failure by alerting responsible personnel, and was later published in 'Biopreservation and Biobanking'.
The sampling system was re-used in the second study, a Ugandan project aimed to identify African swine fever (ASF) in pigs. In this study Ndumu virus, a relatively unstudied virus previously only found in culicine mosquitoes, was discovered in domestic pigs.
For the third study, collaboration with ILRI continued with a study analyzing the 'Muguga Cocktail', the live vaccine currently used to control Theileria parva, a protozoan parasite causing East Coast Fever (ECF) in cattle. Live vaccines have many problems, such as high costs, difficult manufacturing, and the risk that misused vaccine will spread the disease. An in-depth study of the three parasite stocks included in the vaccine was performed, where genomic differences were identified with the goal of explaining the success of the vaccine, as well as identify a potential set of antigens which may in the future replace the live vaccine with a subunit vaccine.
Finally, for the fourth study, the metagenomic theme continued with the development of the MetLab, a tool for experimental design and analysis for viral metagenomics projects. The tool consists of three parts: (i) tools to estimate the sequencing needs of a metagenomic project, (ii) simulation tools, allowing users to simulate metagenomics sequencing data, and (iii) the system runs metagenomic analysis pipelines
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