1,264 research outputs found

    Gonads without glp-1: Silencing glp-1 in the Male Somatic Gonad in Caenorhabditis elegans

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    In C. elegans, the gene glp-1 encodes for a Notch receptor called GLP-1, one of two found in C. elegans’ genome. The gene has been previously implicated in the development of the hermaphroditic germline as well as playing a role in the mitosis/meiosis decision. Genetic screening has further identified it as potentially playing a role in the development of the male somatic gonad, making it an ideal candidate for a reverse genetic. We did this by silencing glp-1 and observing if any alterations to the gonad’s phenotype occur. Normally this could be done by performing a gene knockout. However, due to the nature of Notch receptors’ overall role in the regulation of tissue development, it is an essential gene, and silencing it would result in worms dying as embryos, long before a gonad capable of being studied could form. In order to conduct a knockdown study, CRISPR-Cas was used to tag GLP-1 at its C-terminus with green fluorescent protein (GFP). In a separate strain of worms, degron, a method used for targeting proteins tagged with GFP for ubiquination and lysis, was placed under a promoter specific to the gonad. When the two strains are crossed, they will result in a worm that has functional GLP-1 in all tissues except for the gonad. In order to resolve the sex ratio issue and focus on the development of the male gonad, which has been neglected in the literature, a mutant strain of him-8 worms that produced offspring with a ratio of three males for every ten viable was cultivated. The bulk of our work was spent crossing the degron strain with the him-8 strain, resulting in a new strain of worms that express degron in the gonad and are disproportionately likely to be male. By coupling this strain with the use of CRISPR to tag any gene of interest with GFP, a gonad-specific knockdown study can be performed not only for glp-1 but for any gene expressed in the gonad, essential or not. We crossed the new strain with degron and the mutant him-8 with the glp-1::GFP worms, generating both a produce a worm homozygous for all three genes, which should thus contain adult male worms without GLP-1 in their gonads and a strain with him-8 and glp-1::GFP but not degron, allowing us easy access to a source of a male control group. These we will examine for alterations against the N2 male gonad. In doing so, we will hopefully further understand Notch receptors’ role both in the development of the male gonad as well as in general tissue development

    Impact of Effective Teaching and Learning Process in Schools through Information and Communication Technology (ICT)

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    Technology is developed to solve problems associated with human need in more productive ways, if there is no problem to solve. The technology is not developed and or not adopted. Applying this principle to educational technology would mean that the educators should create and adopt technologies that address educational problems, of which there are many. Further, technology will not be adopted by educators where there is no perceived need or productivity gain. This is what LANSHEAR and SNYDER(2000) refer to as the WORKABILITY PRINCIPLE. Therefore when discussing applications of computer technology to education , the question must always be asked, what educational problems(s) needs to be addressed. This questions needs to be asked at all level of decision making, from the teacher planning a programme, to a school administrator purchasing hardware and software, to an educational system officer developing policy and strategic plans

    ALCH: An Imperative Language for Chemical Reaction Network-Controlled Tile Assembly

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    In 2015 Schiefer and Winfree introduced the chemical reaction network-controlled tile assembly model (CRN-TAM), a variant of the abstract tile assembly model (aTAM), where tile reactions are mediated via non-local chemical signals. In this paper, we introduce ALCH, an imperative programming language for specifying CRN-TAM programs. ALCH contains common features like Boolean variables, conditionals, and loops. It also supports CRN-TAM-specific features such as adding and removing tiles. A unique feature of the language is the branch statement, a nondeterministic control structure that allows us to query the current state of tile assemblies. We also developed a compiler that translates ALCH to the CRN-TAM, and a simulator that simulates and visualizes the self-assembly of a CRN-TAM program. Using this language, we show that the discrete Sierpinski triangle can be strictly self-assembled in the CRN-TAM. This solves an open problem that the CRN-TAM is capable of self-assembling infinite shapes at scale one that the aTAM cannot. ALCH allows us to present this construction at a high level, abstracting species and reactions into C-like code that is simpler to understand. Our construction utilizes two new CRN-TAM techniques that allow us to tackle this open problem. First, it employs the branching feature of ALCH to probe the previously placed tiles of the assembly and detect the presence and absence of tiles. Second, it uses scaffolding tiles to precisely control tile placement by occluding any undesired binding sites

    Differences in IT effectiveness among firms: An empirical investigation

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    Information is a critical asset and an important source for gaining competitive advantage in firms. The effective maintenance of IT becomes an important task. In order to better understand the determinants of IT effectiveness, this study employs the Industrial Organization (I/O) and Resource Based View (RBV) theories and investigates the industry effect and several major firmspecific factors in relation to their impact on firms’ IT effectiveness. The data consist of a panel data of ten-year observations of firms whose IT excellence had been recognized by the CIO Magazine. The non-profit organizations were deliberately excluded, as explained later. The results showed that the effectiveness of IT management varied significantly across industries. Industry also moderated the effects of firm demographic factors such as size and age on IT effectiveness. Surprisingly, R & D investment intensity had negative correlation to IT effectiveness. For managers and practitioners, this study offers some insights for evaluation criteria and expectation for IT project success. Finally, the empirical results indicate that the sustainability of IT effectiveness appears to be short in duration

    AN ASSESSMENT OF FACTORS INFLUENCING THE MANAGEMENT OF COVID-19 PANDEMIC AMONG COUNTY GOVERNMENTS IN KENYA

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    The global pandemic of Covid-19 created dramatic challenges for governments worldwide. It led to skyrocketing numbers of deaths and outbreaks, challenged the public and private health systems of many countries and brought many national economies to a halt. Kenya was not an exception and like other countries used a number of strategies to combat the epidemic but equally suffered the same fate. There is little empirical evidence to determine whether the strategies, especially by the county governments were effective in handling the Covid-19 pandemic. Thereby lies the knowledge gap that this study seeks to answer. It is against this background that this study sought to assess the extent to which medical equipment and supplies, personnel and funding influenced the management of the Covid-19 pandemic by county governments in Kenya. The general objective guiding the study was, to assess the factors influencing the management of the Covid-19 pandemic among county governments in Kenya. The specific objectives of the study were: To determine the extent to which medical equipment and supplies influenced the management of the Covid-19 pandemic in the county governments, to determine the extent to which the use of personnel resources influenced the management of the Covid-19 pandemic in the county governments and to determine the extent to which funding influenced the management of Covid-19 pandemic in the county governments. Fink's crisis management model guided the study, which reviewed the empirical literature on medical equipment and supplies, personnel resources and funding in the management of the Covid-19 pandemic. This study adopted a descriptive survey research design with a target population of 70,500 employees from the health sector. The research used simple random sampling as a sampling technique and a sample size of 100 respondents was selected using the Yamane formula. Data was collected using questionnaires. The data were subjected to descriptive statistics and analyzed using SPSS. Based on the findings, 79.6% of the respondents agreed that medical equipment and supplies greatly influenced the management of the Covid-19 pandemic in the county governments, 85% of the respondents indicated that personnel resources played a critical role in the management of Covid-19 pandemic among the counties and 74.2% of the respondents agreed that funding greatly influenced management of Covid-19 pandemic in county governments. Based on the findings, the study recommended that a staff audit and workload analysis should be undertaken and a recruitment process initiated to improve staffing levels; an audit of bed capacity of all medical facilities be initiated and a procurement plan for the acquisition of additional beds based on needs undertaken; an audit and analysis of staff training be undertaken to identify training gaps and necessary action initiated; negotiate with SRC on additional medical staff allowances and lastly fast-track legislation on the expenditure of emergency funds. JEL: H10; H51; H76; I10; I18  Article visualizations

    Frequent malaria illness episodes in two Malawian patients on antiretroviral therapy soon after stopping cotrimoxazole preventive therapy

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    We describe two Malawian adults on successful antiretroviral therapy who experienced frequent malaria episodes after stopping cotrimoxazole prophylaxis. We argue that, in addition to stopping cotrimoxazole, diminished malaria immunity and drug interactions between efavirenz and artemether–lumefantrine may have played a causative role in the recurrent malaria our patients experienced

    Using a whole-body 31P birdcage transmit coil and 16-element receive array for human cardiac metabolic imaging at 7T.

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    PURPOSE: Cardiac phosphorus magnetic resonance spectroscopy (31P-MRS) provides unique insight into the mechanisms of heart failure. Yet, clinical applications have been hindered by the restricted sensitivity of the surface radiofrequency-coils normally used. These permit the analysis of spectra only from the interventricular septum, or large volumes of myocardium, which may not be meaningful in focal disease. Löring et al. recently presented a prototype whole-body (52 cm diameter) transmit/receive birdcage coil for 31P at 7T. We now present a new, easily-removable, whole-body 31P transmit radiofrequency-coil built into a patient-bed extension combined with a 16-element receive array for cardiac 31P-MRS. MATERIALS AND METHODS: A fully-removable (55 cm diameter) birdcage transmit coil was combined with a 16-element receive array on a Magnetom 7T scanner (Siemens, Germany). Electro-magnetic field simulations and phantom tests of the setup were performed. In vivo maps of B1+, metabolite signals, and saturation-band efficiency were acquired across the torsos of eight volunteers. RESULTS: The combined (volume-transmit, local receive array) setup increased signal-to-noise ratio 2.6-fold 10 cm below the array (depth of the interventricular septum) compared to using the birdcage coil in transceiver mode. The simulated coefficient of variation for B1+ of the whole-body coil across the heart was 46.7% (surface coil 129.0%); and the in vivo measured value was 38.4%. Metabolite images of 2,3-diphosphoglycerate clearly resolved the ventricular blood pools, and muscle tissue was visible in phosphocreatine (PCr) maps. Amplitude-modulated saturation bands achieved 71±4% suppression of phosphocreatine PCr in chest-wall muscles. Subjects reported they were comfortable. CONCLUSION: This easy-to-assemble, volume-transmit, local receive array coil combination significantly improves the homogeneity and field-of-view for metabolic imaging of the human heart at 7T
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