104 research outputs found
Sol-Gel Technology in Enhancing the Filtration of Semi-Volatile Organic Compounds
For the past several years, the field of sol-gel technology has undergone remarkable growth in areas ranging from micro-fibers to chemical sensors. Incorporating an organic phase into the colloidal mixture via pre- or post-doping can modify sol-gels, and manipulation of the size of the pores can be used in developing \u27eco-friendly\u27 water filters, particularly for filtering semi-volatile organic compounds in water. In this research project, various forms of sol-gels were made to see which is more efficient for certain semi-volatile chemicals that can be found in diverse sources of water. Organically modified silicates and different structurally sound sol-gels were made to determine which type of sol-gel material provides the most effective water filter
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Zc3h10 Acts as a Transcription Factor and Is Phosphorylated to Activate the Thermogenic Program.
Brown adipose tissue harbors UCP1 to dissipate chemical energy as heat. However, the transcriptional network that governs the thermogenic gene program is incompletely understood. Zc3h10, a CCCH-type zinc finger protein, has recently been reported to bind RNA. However, we report here that Zc3h10 functions as a transcription factor to activate UCP1 not through the enhancer region, but by binding to a far upstream region of the UCP1 promoter. Upon sympathetic stimulation, Zc3h10 is phosphorylated at S126 by p38 mitogen-activated protein kinase (MAPK) to increase binding to the distal region of the UCP1 promoter. Zc3h10, as well as mutant Zc3h10, which cannot bind RNA, enhances thermogenic capacity and energy expenditure, protecting mice from diet-induced obesity. Conversely, Zc3h10 ablation in UCP1+ cells in mice impairs thermogenic capacity and lowers oxygen consumption, leading to weight gain. Hence, Zc3h10 plays a critical role in the thermogenic gene program and may present future targets for obesity therapeutics
Effect of maximum lift to drag ratio on optimal aeroassisted plane change
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76843/1/AIAA-1985-1817-421.pd
The darboux point and the conjugate point on optimal deorbit for reentry trajectories
The concept of the Darboux point at which an extremal loses its global optimality is extended to the case of discontinuous control. Using Contensou's domain of maneuverability, the condition for optimal switching at a corner is derived and the optimality of the trajectory in the neighborhood of a Darboux point is analyzed. The theory is applied to the problems of minimum-fuel planar and noncoplanar deorbit from elliptical orbits for atmospheric entry at a prescribed angle. In each case, the global optimal trajectory is assessed and it is found that in these nonlinear problems the Darboux point and the conjugate point are distinct. The global optimality is always lost before local optimality.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25561/1/0000103.pd
Optimal aeroassisted transfer between coplanar elliptical orbits
This paper presents the solution for minimum-fuel, free-time transfer between coplanar elliptical orbits with the possible use of a planetary atmosphere to generate a decelerative braking force. The optimal pure propulsive two-impulse transfer is first considered. It is shown that the solution is obtained by solving a set of three equations for three unknowns. Reduction of the general equations is made for the case of symmetrical transfer and a complete first-order solution is provided for the case of transfer from nearly circular orbit. In aeroassisted transfer atmospheric braking at the perigee can be used to circularize the orbit, and in the circular configuration the orbit can be arbitrarily rotated without fuel consumption. It is shown that complete circularization of this intermediary orbit is optimal only when the rotation angle is large, and an explicit formula for evaluating this critical angle is provided. A complete solution is presented for the case of optimal rotation of an orbit. Finally, an example of optimal aeroassisted transfer is provided for the case of a transfer from a low-energy orbit to a high-energy orbit.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26152/1/0000229.pd
Genetic characterization of a multidrug-resistant Salmonella enterica serovar Agona isolated from a dietary supplement in Germany
Salmonella enterica subsp. enterica serovar Agona has a history of causing food-borne outbreaks and any emergence of multidrug-resistant (MDR) isolates in novel food products is of concern. Particularly, in food products frequently consumed without sufficient heating prior to consumption. Here, we report about the MDR isolate, 18-SA00377, which had been isolated from a dietary supplement in Germany in 2018 and submitted to the German National Reference Laboratory for Salmonella. WGS-based comparative genetic analyses were conducted to find a potential reservoir of the isolate itself or mobile genetic elements associated with MDR. As a phylogenetic analysis did not yield any closely related S. Agona isolates, either globally or from Germany, a detailed analysis of the largest plasmid (295,499 bp) was performed as it is the main carrier of resistances. A combined approach of long-read and short-read sequencing enabled the assembly of the isolate’s chromosome and its four plasmids. Their characterization revealed the presence of 23 different antibiotic resistance genes (ARGs), conferring resistance to 12 different antibiotic drug classes, as well as genes conferring resistance to six different heavy metals. The largest plasmid, pSE18-SA00377-1, belongs to the IncHI2 plasmid family and carries 16 ARGs, that are organized as two distinct clusters, with each ARG associated with putative composite transposons. Through a two-pronged approach, highly similar plasmids to pSE18-SA00377-1 were identified in the NCBI database and a search for Salmonella isolates with a highly similar ARG resistance profile was conducted. Mapping and structural comparisons between pSE18-SA00377-1 and these plasmids and Salmonella isolates showed that both the plasmid backbone and identical or similar ARG clusters can be found not only in Salmonella isolates, originating mostly from a wide variety of livestock, but also in a diverse range of bacterial genera of varying geographical origins and isolation sources. Thus, it can be speculated that the host range of pSE18-SA00377-1 is not restricted to Salmonella and its spread already occurred in different bacterial populations. Overall, this hints at a complex history for pSE18-SA00377-1 and highlights the importance of surveilling multidrug-resistant S. enterica isolates, especially in novel food items that are not yet heavily regulated
The repeatability and heritability of traits derived from accelerometer sensors associated with grazing and rumination time in an extensive sheep farming system
IntroductionThe automated collection of phenotypic measurements in livestock is of interest to both researchers and farmers. Real-time, low-cost, and accurate phenotyping can enhance precision livestock management and could lead to the optimized utilization of pasture and breeding of efficient animals. Wearable sensors provide the tools for researchers to develop novel phenotypes across all production systems, which is especially valuable for grazing conditions. The objectives of this study were to estimate the repeatability and heritability of traits related to grazing and rumination activities and their correlations with other traits.MethodsThis study was conducted on a commercial Merino farm in the west of Victoria, Australia, from 4 May 2020 to 29 May 2020. A total of 160 ActiGraph sensors embedded in halters were attached to the left side of the muzzles of Merino sheep (M = 74, F = 86) aged 10–11 months while the sheep were grazing on pasture. Support vector machine (SVM) algorithms classified the sensor output into the categories of grazing, rumination, walking, idle, and other activities. These activities were further classified into daily grazing time (GT), number of grazing events (NGE), grazing length (GL), rumination time (RT), number of rumination events (NRE), rumination length (RL), walking time (WT), and idle time (IT). The data were analyzed using univariate and bivariate models in ASReml-SA to estimate the repeatability, heritability, and phenotypic correlations among traits.ResultsThe heritability of GT was estimated to be 0.44 ± 0.23, whereas the other traits had heritability estimates close to zero. The estimated repeatability for all traits was moderate to high, with the highest estimate being for GT (0.70 ± 0.03) and the lowest for RT (0.44 ± 0.03). The intraclass correlation or repeatability at a 1-day interval (i.e., 2 consecutive days) was high for all traits, and steadily reduced when the interval between measurements was longer than 1 week.DiscussionThe estimated repeatability for the grazing traits showed that wearable sensors and SVM methods are reliable methods for recording sheep activities on pasture, and have a potential application in the ranking of animals for selective breeding
Explicit guidance of drag-modulated aeroassisted transfer between elliptical orbits
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77072/1/AIAA-20103-582.pd
The Evolution of the English Language Institute: Curriculum and Structural Reform
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