181 research outputs found

    Cell cycle length, cell size, and proliferation rate in hydra stem cells

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    We have analyzed the cell cycle parameters of interstitial cells in Hydra oligactis. Three subpopulations of cells with short, medium, and long cell cycles were identified. Short-cycle cells are stem cells; medium-cycle cells are precursors to nematocyte differentiation; long-cycle cells are precursors to gamete differentiation. We have also determined the effect of different cell densities on the population doubling time, cell cycle length, and cell size of interstitial cells. Our results indicate that decreasing the interstitial cell density from 0.35 to 0.1 interstitial cells/epithelial cell (1) shortens the population doubling time from 4 to 1.8 days, (2) increases the [3H]thymidine labeling index from 0.5 to 0.75 and shifts the nuclear DNA distribution from G2 to S phase cells, and (3) decreases the length of G2 in stem cells from 6 to 3 hr. The shortened cell cycle is correlated with a significant decrease in the size of interstitial stem cells. Coincident with the shortened cell cycle and increased growth rate there is an increase in stem cell self-renewal and a decrease in stem cell differentiation

    Intermediate Variable Elimination in a Global Context for a 3D Multimedia Application

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    The 3D multimedia applications have been experiencing recently a tremendous growth in number and complexity. Such applications mainly consist of complex algorithms that process extensive amounts of data to create 3D images and results. For quick access, data need to be stored in small and expensive memories near the processor. Due to the increasing memory-processor gap in speed and the characteristics of multimedia applications (with highly power- and space- consuming data sets), software transformations are required to decrease memory requirements. In this paper, we propose a method to reduce the indirections of data types in real 3D multimedia applications. It is based on software transformations of the original algorithm to minimize the intermediate assignments and, as such, the required data types. To assess the performance of our method, we apply it to a relatively new 3D image reconstruction application. As a result, for this multimedia application, our method reduces 50× the amount of memory accesses, 30× the normalized memory footprint and 67× the energy consumption compared to a manually well-optimized version of the algorithm. Finally, compared to the original application, the overall performance improves by 40% on a PC

    Determination of Iron and Zinc Absorption by Local Isolates of Saccharomyces cerevisiae to Produce Iron and Zinc in Organic Form

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    Iron (Fe) and Zinc (Zn) play important role in health both of live stock and human. Fe and Zn in organic form were claimed increasing their viabilities. They bind to certain amino acid formed as a product of microbial metabolism. The Amount Fe and Zn absorbed may indicated the Fe and Zn organic produced. The aim of the study is to determine the absorption of microelement of Fe and Zn by local isolates of Saccharomyces cerevisiae to produce Fe and Zn in organic forms. S. cerevisae BCC F0205, BCC F0206, and BCC F0214 were treated with Fe or Zn 10 ppm to obtain S. cerevisae which has the highest of total concentration of Fe and Zn. Selected isolate was then treated with Fe or Zn respectively 2.5, 5, 10 ppm and their combination. Fe and Zn absorbed by isolates were measured by Atomic Absorption Spectrophotometer (AAS). The results show that  S. cerevisae BCC F0205, BCC F0206, and BCC F0214 treated with 10 ppm Fe or Zn contained total concentration of Fe respectively 1.57, 3.07, 2.24 ppm  and total concentration of Zn respectively 2.34, 3.20, 3.13 ppm. Then, S. cerevisae BCC F0206 treated with 2.5, 5, 10 ppm Fe or Zn, absorbed Fe 1.45, 0.50, 0.94 ppm and Zn 0.73, 0.38, 0.53 ppm respectively. Furthermore, combination of Fe and Zn (2.5:2.5, 5:5, 10:10 ppm) produce absorption of Fe 3.10, 2.13, 3.67 ppm and Zn 0.11, 0.10, 0.28 ppm per gram S. cerevisae BCC F0206. Percentages of absorption by S. cerevisae are up to 100% for Fe and up to 47.20% for Zn. In conclusion, this study indicated that S. cerevisae BCC F0206 absorb Fe and Zn higher than BCC F0205 and BCC F0214 and there are antagonistic interactions found between Fe and Zn in this research

    Effect of Returning University Students on COVID-19 Infections in England, 2020

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    Each September in England, ≈1 million students relocate to study at universities. To determine COVID-19 cases and outbreaks among university students after their return to university during the COVID pandemic in September 2020, we identified students with COVID-19 (student case-patients) by reviewing contact tracing records identifying attendance at university and residence in student accommodations identified by matching case-patients’ residential addresses with national property databases. We determined COVID-19 rates in towns/cities with and without a university campus. We identified 53,430 student case-patients during September 1–December 31, 2020, which accounted for 2.7% of all cases during this period. Student case-patients increased rapidly after the start of the term, driven initially by cases and outbreaks in student accommodations. Case rates among students 18–23 years of age doubled at the start of term in towns with universities. Our findings highlight the need for face-to-face and control measures to reduce virus transmission

    Methodology for Refinement and Optimization of Dynamic Memory Management for Embedded Systems in Multimedia Applications

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    In multimedia applications, run-time memory management support has to allow real-time memory de/allocation, retrieving and processing of data. Thus, its implementation must be designed to combine high speed, low power, large data storage capacity and a high memory bandwidth. In this paper, we assess the performance of our new system-level exploration methodology to optimize the memory management of typical multimedia applications in an extensively used 3D reconstruction image system. This methodology is based on an analysis of the number of memory accesses, normalized memory use 1 and energy estimations for the system studied. This results in an improvement of normalized memory footprint up to 44.2% and the estimated energy dissipation up to 22.6% over conventional static memory implementations in an optimized version of the driver application. Finally, our final version is able to scale perfectly the memory consumed in the system for a wide range of input parameters whereas the statically optimized version is unable to do this

    Automated dynamic memory data type implementation exploration and optimization

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    The behavior of many algorithms is heavily determined by the input data. Furthermore, this often means that multiple and completely different execution paths can be followed, also internal data usage and handling is frequently quite different. Therefore, static compile time memory allocation is not efficient, especially on embedded systems where memory is a scarce resource, and dynamic memory management is the only feasible alternative. Including applications with dynamic memory in embedded systems introduces new challenges as compared to traditional signal processing applications. In this session, an automated framework is presented to optimize embedded applications with extensive use of dynamic memory management. The proposed methodology automates the exploration and identification of optimal data type implementations based on power estimates, memory accesses and normalized memory usage

    Some Experiences on Dynamic Memory Management Refinement at System-Level for Multimedia Applications

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    Nowadays, 3D multimedia applications have grown rapidly in number and consist of complex systems (e.g. 3D graphical processing or games) that process extensive amounts of data to create 3D images and results. This produces highcost and high-power consumption systems whereas a superior portability demands cheap and low-power consumption ones. In these multimedia applications, the dynamic memory subsystem is currently one of the main sources of power consumption and its inattentive management can affect severely the performance and power consumption of the whole system. In this paper, we illustrate a new system-level method to explore and refine the dynamic memory management of multimedia systems on current typical case studies, i.e. a relatively new 3D image reconstruction system and a 3D simulation game. This method is based on an analysis of the access pattern, amount of memory used and power consumption estimations. With this information, a phasewise exploration and refinement flow is used to optimize the system at the different phases of its hardware-oriented design process. As the results in the case studies show, our system-level method achieves great improvements in memory footprint, power consumption and performance for multimedia applications

    Reliable identification of women with CIN3+ using hrHPV genotyping and methylation markers in a cytology-screened referral population.

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    Cervical screening aims to identify women with high-grade squamous intraepithelial lesion/cervical intraepithelial neoplasia 2-3 (HSIL/CIN2-3) or invasive cervical cancer (ICC). Identification of women with severe premalignant lesions or ICC (CIN3+) could ensure their rapid treatment and prevent overtreatment. We investigated high-risk human papillomavirus (hrHPV) detection with genotyping and methylation of FAM19A4/miR124-2 for detection of CIN3+ in 538 women attending colposcopy for abnormal cytology. All women had an additional cytology with hrHPV testing (GP5+/6+-PCR-EIA+), genotyping (HPV16/18, HPV16/18/31/45), and methylation analysis (FAM19A4/miR124-2) and at least one biopsy. CIN3+ detection was studied overall and in women <30 (n = 171) and ≥30 years (n = 367). Positivity for both rather than just one methylation markers increased in CIN3, and all ICC was positive for both. Overall sensitivity and specificity for CIN3+ were, respectively, 90.3% (95%CI 81.3-95.2) and 31.8% (95%CI 27.7-36.1) for hrHPV, 77.8% (95%CI 66.9-85.8) and 69.3% (95%CI 65.0-73.3) for methylation biomarkers and 93.1% (95%CI 84.8-97.0) and 49.4% (95%CI 44.8-53.9) for combined HPV16/18 and/or methylation positivity. For CIN3, hrHPV was found in 90.9% (95%CI 81.6-95.8), methylation positivity in 75.8% (95%CI 64.2-84.5) and HPV16/18 and/or methylation positivity in 92.4% (95%CI 83.5-96.7). In women aged ≥30, the sensitivity of combined HPV16/18 and methylation was increased (98.2%, 95%CI 90.6-99.7) with a specificity of 46.3% (95%CI 40.8-51.9). Combination of HPV16/18 and methylation analysis was very sensitive and offered improved specificity for CIN3+, opening the possibility of rapid treatment for these women and follow-up for women with potentially regressive, less advanced, HSIL/CIN2 lesions
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