438 research outputs found

    Study of dopants for radiation-resistant silicon Final report

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    Radiation effects on electrical properties of both aluminum and lithium doped bulk silico

    Model formulations for pickup and delivery problems in designated driver services

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    Designated driver services use company vehicles to deliver drivers to customers. The drivers then drive the customers from their origins to their destinations in the customers’ own cars; at the destinations, the drivers are picked up by a company vehicle. We typically see teams of drivers assigned to company vehicles serving customers. However, when the drivers may be dropped off by one vehicle and picked up by another, a challenging pick-up and delivery problem arises. In this paper, we study the structural properties of the designated driver problem focusing on the synchronization between company vehicles and drivers. We present a two-index formulations to generate optimal, least-cost routes using a general-purpose solver. We benchmark the two-index formulations against a 3-index formulation and a path enumeration strategy. Based on a set of experiments, we find that the two-index formulation performs well, both in terms of quality and solution time, especially on the formulations with more flexibility in the pairing of drivers to company vehicles. Our computational experiments show that up to 75% cost savings are possible from using a flexible operating strategy as compared to a strategy in which drivers and company vehicles stay together throughout a shift

    Model formulations for pickup and delivery problems in designated driver services

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    Designated driver services use company vehicles to deliver drivers to customers. The drivers then drive the customers from their origins to their destinations in the customers’ own cars; at the destinations, the drivers are picked up by a company vehicle. We typically see teams of drivers assigned to company vehicles serving customers. However, when the drivers may be dropped off by one vehicle and picked up by another, a challenging pick-up and delivery problem arises. In this paper, we study the structural properties of the designated driver problem focusing on the synchronization between company vehicles and drivers. We present a two-index formulations to generate optimal, least-cost routes using a general-purpose solver. We benchmark the two-index formulations against a 3-index formulation and a path enumeration strategy. Based on a set of experiments, we find that the two-index formulation performs well, both in terms of quality and solution time, especially on the formulations with more flexibility in the pairing of drivers to company vehicles. Our computational experiments show that up to 75% cost savings are possible from using a flexible operating strategy as compared to a strategy in which drivers and company vehicles stay together throughout a shift

    Integrating Data Collection Optimization into Pavement Management Systems

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    This paper describes a method for using location data to optimize the routing of pavement data collection vehicles. In much of the developed world, pavement testing is performed on a regular basis; the pavement testing data, in turn, serves as input to Pavement Management Systems. Currently, in the United States of America, state departments of transportation plan this data collection work by providing the list of roads that must be tested and then leave the routing of the vehicles to the equipment operators who typically execute the work in an ad hoc manner. This study presents the processes required to code the list of roads for testing, select appropriate hotels in the region of testing, and apply a Traveling Salesman Problem with Hotel Stops model to derive a route. Applying the processes to a case study shows significant cost savings associated with this method of roadway testing, as opposed to the current ad hoc methods

    Emergency Management System Design for Accurate Data: A Case Study

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    In any city – smart or not – emergency response is a critical service. In smart cities, the use of technology to manage access to and dispatching of emergency vehicles is particularly important. However, when a system must manage processes spanning multiple computers, clock drift becomes a prominent issue. We show the impact that clock drift can have in a prototype emergency management dispatch system along with a case-study illustrating design techniques that can remedy this issue

    Ames hypopituitary dwarf mice demonstrate imbalanced myelopoiesis between bone marrow and spleen

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    Ames hypopituitary dwarf mice are deficient in growth hormone, thyroid-stimulating hormone, and prolactin. The phenotype of these mice demonstrates irregularities in the immune system with skewing of the normal cytokine milieu towards a more anti-inflammatory environment. However, the hematopoietic stem and progenitor cell composition of the bone marrow (BM) and spleen in Ames dwarf mice has not been well characterized. We found that there was a significant decrease in overall cell count when comparing the BM and spleen of 4-5 month old dwarf mice to their littermate controls. Upon adjusting counts to differences in body weight between the dwarf and control mice, the number of granulocyte-macrophage progenitors, confirmed by immunophenotyping and colony-formation assay was increased in the BM. In contrast, the numbers of all myeloid progenitor populations in the spleen were greatly reduced, as confirmed by colony-formation assays. This suggests that there is a shift of myelopoiesis from the spleen to the BM of Ames dwarf mice; however, this shift does not appear to involve erythropoiesis. The reasons for this unusual shift in spleen to marrow hematopoiesis in Ames dwarf mice are yet to be determined but may relate to the decreased hormone levels in these mice

    Detection of a highly prevalent and potentially virulent strain of Pseudomonas aeruginosa from nosocomial infections in a medical center

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    BACKGROUND: We correlated genotypes, virulence factors and antimicrobial susceptibility patterns of nosocomially identified Pseudomonas aeruginosa isolates from clinical specimens to those of environmental isolates encountered in the same units of a medical center. Antibiotic susceptibility testing, RAPD analysis and detection of enzymatic activities of extracellular virulence factors, were done on these isolates. RESULTS: Data showed that most of the clinical and environmental isolates were susceptible to tested antimicrobial agents. RAPD analysis determined the presence of 31 genotypes, with genotype 1 detected in 42% of the clinical isolates and 43% of the environmental isolates. Enzymatic activity testing showed that genotype 1 produced all virulence factors tested for. CONCLUSION: In conclusion, our data demonstrated the predominant prevalence of a potentially virulent P. aeruginosa genotype, circulating in a number of units of the medical center and emphasize the need to reinforce infection control measures

    Tamm-Horsfall Protein Regulates Mononuclear Phagocytes in the Kidney

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    Tamm-Horsfall protein (THP), also known as uromodulin, is a kidney-specific protein produced by cells of the thick ascending limb of the loop of Henle. Although predominantly secreted apically into the urine, where it becomes highly polymerized, THP is also released basolaterally, toward the interstitium and circulation, to inhibit tubular inflammatory signaling. Whether, through this latter route, THP can also regulate the function of renal interstitial mononuclear phagocytes (MPCs) remains unclear, however. Here, we show that THP is primarily in a monomeric form in human serum. Compared with wild-type mice, THP-/- mice had markedly fewer MPCs in the kidney. A nonpolymerizing, truncated form of THP stimulated the proliferation of human macrophage cells in culture and partially restored the number of kidney MPCs when administered to THP-/- mice. Furthermore, resident renal MPCs had impaired phagocytic activity in the absence of THP. After ischemia-reperfusion injury, THP-/- mice, compared with wild-type mice, exhibited aggravated injury and an impaired transition of renal macrophages toward an M2 healing phenotype. However, treatment of THP-/- mice with truncated THP after ischemia-reperfusion injury mitigated the worsening of AKI. Taken together, our data suggest that interstitial THP positively regulates mononuclear phagocyte number, plasticity, and phagocytic activity. In addition to the effect of THP on the epithelium and granulopoiesis, this new immunomodulatory role could explain the protection conferred by THP during AKI

    Diazo ester insertion in N-H bonds of amino acid derivatives and insulin catalyzed by water-soluble iron and ruthenium porphyrin complexes (FeTSPPCl) as application of carbenoid transfer in aqueous media

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    International audienceThe metal complex FeTSPPCl (5,10,15,20-tetrakis)-(4-sulfonato-phenyl)-porphyrin-iron(III) chloride is an active catalyst for carbenoid insertion in N–H bonds of aminoacid derivatives in aqueous media. A variety of diazoacetates and methyl diazophosphonate were used as carbenoid precursors. The commercially available iron porphyrin complex can also selectively catalyze alkylation of the N-terminus of insulin (chain B

    A novel role for thrombopoietin in regulating osteoclast development in humans and mice

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    Emerging data suggest that megakaryocytes (MKs) play a significant role in skeletal homeostasis. Indeed, osteosclerosis observed in several MK-related disorders may be a result of increased numbers of MKs. In support of this idea, we have previously demonstrated that MKs increase osteoblast (OB) proliferation by a direct cell-cell contact mechanism and that MKs also inhibit osteoclast (OC) formation. As MKs and OCs are derived from the same hematopoietic precursor, in these osteoclastogenesis studies we examined the role of the main MK growth factor, thrombopoietin (TPO) on OC formation and bone resorption. Here we show that TPO directly increases OC formation and differentiation in vitro. Specifically, we demonstrate the TPO receptor (c-mpl or CD110) is expressed on cells of the OC lineage, c-mpl is required for TPO to enhance OC formation in vitro, and TPO activates the mitogen-activated protein kinases, Janus kinase/signal transducer and activator of transcription, and nuclear factor-kappaB signaling pathways, but does not activate the PI3K/AKT pathway. Further, we found TPO enhances OC resorption in CD14+CD110+ human OC progenitors derived from peripheral blood mononuclear cells, and further separating OC progenitors based on CD110 expression enriches for mature OC development. The regulation of OCs by TPO highlights a novel therapeutic target for bone loss diseases and may be important to consider in the numerous hematologic disorders associated with alterations in TPO/c-mpl signaling as well as in patients suffering from bone disorders
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