3,756 research outputs found
The Effects of Language Difference on Operational Performance and Satisfaction with B2B E-Marketplace Interface
This study integrated the user interface and information content of the business-to-business (B2B) electronic marketplace (e-marketplace) with language to analyze whether language differences affect the definition of good interface design and the information content that should be provided via an e-marketplace. An experimental design was adopted for collecting data from tasks, and then the Questionnaire for User Interface Satisfaction (QUIS) was used to ascertain how satisfied subjects were with regard to using the B2B e-marketplace interfaces. Study results showed that the language, the e-marketplace interface the subject used, and a combination of the two predict a person’s operational performance and satisfaction with a B2B e-marketplace. This study’s results provide a better understanding of whether B2B e-marketplace service providers should develop interfaces based on specific languages
Ground-state properties via machine learning quantum constraints
Ground-state properties are central to our understanding of quantum many-body
systems. At first glance, it seems natural and essential to obtain the ground
state before analyzing its properties; however, its exponentially large Hilbert
space has made such studies costly, if not prohibitive, on sufficiently large
system sizes. Here, we propose an alternative strategy based upon the
expectation values of an ensemble of operators and the elusive yet vital
quantum constraints between them, where the search for ground-state properties
simply equates to simple, classical constrained minimization. These quantum
constraints are generally obtainable via machine learning on a large number of
sample quantum many-body states systematically consistent with physical
presumptions. We showcase our perspective on 1D fermion chains and spin chains
for applicability, effectiveness, and several unique advantages, especially for
strongly correlated systems, thermodynamic-limit systems, property designs,
etc.Comment: 6 pages, 4 figure
Optimization of human T cell expansion ex vivo using serum-free medium and the gas- permeable rapid expansion cell culture devices (G-Rex)
Adoptive immunotherapy with ex vivo-modified T cells shows immense promise as an emerging strategy for patients with advanced malignancies. Although promising, most current methods for expansion of gene-modified T cells ex vivo are complicated and labor intensive, limiting the broad application of adoptive immunotherapy in the future. Traditional T cell expansion protocols are marked by flaws in consistency, safety, the frequency of human intervention required, and the length of the manufacturing process. These expansion protocols have traditionally involved the use human serum, which is characterized by batch inconsistency, and can potentially expose the patient to adverse viral contamination. Moreover, the duration of the expansion phase has typically been 10-12 days and involves extensive hands-on operation, while an ideal process would be significantly shorter and require minimal cellular disturbance. For the purpose of safety and consistency, serum-free T cell expansion media have been developed, and to minimize complexity of the manufacturing process, many researchers in the field are turning to the Gas Permeable Rapid Expansion (G-Rex) culture platform, which has shown superior cell output and a reduction in the number of required technician manipulations compared to conventional approaches. However, to date, there is a dearth of knowledge regarding the use of serum-free media in G-Rex systems. To this end, we tested several commercially available serum-free media to see how effectively they could expand human T cells in the G-Rex culture system. The results demonstrated that none of the serum-free media consistently performed as well as conventional methods that employ serum-containing culture media. However, when we further supplemented the best performer from this cohort of serum-free media with 4mM GlutaMAX™ and 2% of a chemically defined serum replacement, this medium supported ample T cell expansion, with yields similar to or better than media containing human serum. Furthermore, the resultant cell population displayed a higher frequency of the desirable central memory phenotype than the cells grown in serum-containing media and was indistinguishable from the serum-grown population with regards to both CD8/CD4 ratio and functionality. We conclude that combining serum-free media with the G-Rex culture platform can be effective for human T cell expansion and that applying this cell culture strategy to the production of T cell therapies could potentially address some of the concerns associated with traditional protocols by ensuring safety and consistency, shortening the expansion phase, and reducing the excessive amount of technical intervention required
Capulet and Slingshot share overlapping functions during Drosophila eye morphogenesis
BACKGROUND: CAP/Capulet (Capt), Slingshot (Ssh) and Cofilin/Twinstar (Tsr) are actin-binding proteins that restrict actin polymerization. Previously, it was shown that low resolution analyses of loss-of-function mutations in capt, ssh and tsr all show ectopic F-actin accumulation in various Drosophila tissues. In contrast, RNAi depletion of capt, tsr and ssh in Drosophila S2 cells all affect actin-based lamella formation differently. Whether loss of these three related genes might cause the same effect in the same tissue remains unclear. METHODS: Loss-of-function mutant clones were generated using the MARCM or EGUF system whereas overexpression clones were generated using the Flip-out system. Immunostaining were then performed in eye imaginal discs with clones. FRAP was performed in cultured eye discs. RESULTS: Here, we compared their loss-of-function phenotype at single-cell resolution, using a sheet of epithelial cells in the Drosophila eye imaginal disc as a model system. Surprisingly, we found that capt and ssh, but not tsr, mutant cells within and posterior to the morphogenetic furrow (MF) shared similar phenotypes. The capt/ssh mutant cells possessed: (1) hexagonal cell packing with discontinuous adherens junctions; and (2) largely complementary accumulation of excessive phosphorylated myosin light chain (p-MLC) and F-actin rings at the apical cortex. We further showed that the capt/ssh mutant phenotypes depended on the inactivation of protein kinase A (PKA) and activation of Rho. CONCLUSIONS: Although Capt, Ssh and Tsr were reported to negatively regulate actin polymerization, we found that Capt and Ssh, but not Tsr, share overlapping functions during eye morphogenesis
Environmental and Energy Assessment of Biomass Residues to Biochar as Fuel: A Brief Review with Recommendations for Future Bioenergy Systems
This study explores the environmental and energy benefits of biomass residues, including crop residues and agricultural waste, for the production of renewable energy in the form of biochar as fuel, in order to offer recommendations for policy makers, by reviewing information regarding the key environmental issues associated with the implementation of the systems. The highest environmental benefits for biochar-to-fuel systems were most observed in reduction of global warming potentials (i.e., carbon abatement), particularly for those integrated with combined heat and power technology, or for those incorporating electricity offsets from biochar combustion and co-firing. But all of these practices come at the cost of hidden environmental burdens, such as elevations in eutrophication, acidification, carcinogens and ecotoxicity impacts, as a consequence from land use change, additional infrastructure requirement or additional fertilizer application connected to biochar production or post-treatment. Other notable challenges, including regional availability of biomass residues, improper management of the residues, limited economic incentives, low energy efficiency and synergies, as well as mistreating adverse impacts from indirect land use change, were discussed. This suggests the flexibility to adjust the biomass-biochar ratio to optimize desired energy yields, carbon abatement and environmental beneficial objectives. Comprehensive analysis of the trade-offs between energy yields, carbon abatement and other associated environmental impacts is therefore recommended for future studies. Future studies in this field are also advised to explore the solution and to develop methodologies capable of quantifying the impacts and other equally relevant trade-offs, to better reflect the changes in real-world trends for decision making
FasL Gene–Deficient Mice Display a Limited Disruption in Spermatogenesis and Inhibition of Mono-(2-ethylhexyl) Phthalate–Induced Germ Cell Apoptosis
FasL (TNFSF6, CD95L) is hypothesized to trigger testicular germ cell apoptosis that normally occurs during a distinct peripubertal period as well as in response to toxicant-induced Sertoli cell injury. To test this hypothesis, we evaluated the testis of FasL gene–deficient mice (FasL−/−) at two distinct developmental ages (postnatal day [PND] 28 and 44) and after toxicant-induced Sertoli cell injury. Testicular cross sections from peripubertal (PND 28) FasL−/− mice showed significant increases in the basal germ cell apoptotic index (AI; 20.58 ± 4.59) as compared to the testis of C57BL/6J wild-type mice (5.16 ± 0.08) and closely correlated with increased expression of TRAIL protein in the testis of FasL−/− mice. A limited, but significant, number of seminiferous tubules in the testis of PND 28 FasL−/− mice showed a severe loss of germ cells with only Sertoli cells present. In contrast, no apparent gross histological changes were observed in the testis of adult (PND 44) FasL−/− mice. However, PND 44 FasL−/− mice did show a 51% reduction in homogenization-resistant elongate spermatids as compared to age-matched C57BL/6J mice. Exposure of PND 28 FasL−/− mice to mono-(2-ethylhexyl) phthalate (MEHP), a well-described Sertoli cell toxicant, unexpectedly caused a rapid decrease in the germ cell AI that paralleled increased levels of the CFLAR (c-FLIP) protein, a known inhibitor of death receptor signaling. In contrast, MEHP treatment did not decrease c-FLIP levels in PND 28 C57BL/6J mice. Taken together, these findings indicate that FasL protein expression is required during the peripubertal period for the proper regulation of germ cell apoptosis that occurs normally during this period. The influence of FasL on the cellular regulation of c-FLIP protein levels appears to be a unique mechanism for modulating germ cell apoptosis after toxicant-induced Sertoli cell injury
Attention Allocation for Human Multi-Robot Control: Cognitive Analysis based on Behavior Data and Hidden States
Human multi-robot interaction exploits both the human operator’s high-level decision-making skills and the robotic agents’ vigorous computing and motion abilities. While controlling multi-robot teams, an operator’s attention must constantly shift between individual robots to maintain sufficient situation awareness. To conserve an operator’s attentional resources, a robot with self reflect capability on its abnormal status can help an operator focus her attention on emergent tasks rather than unneeded routine checks. With the proposing self-reflect aids, the human-robot interaction becomes a queuing framework, where the robots act as the clients to request for interaction and an operator acts as the server to respond these job requests. This paper examined two types of queuing schemes, the self-paced Open-queue identifying all robots’ normal/abnormal conditions, whereas the forced-paced shortest-job-first (SJF) queue showing a single robot’s request at one time by following the SJF approach. As a robot may miscarry its experienced failures in various situations, the effects of imperfect automation were also investigated in this paper. The results suggest that the SJF attentional scheduling approach can provide stable performance in both primary (locate potential targets) and secondary (resolve robots’ failures) tasks, regardless of the system’s reliability levels. However, the conventional results (e.g., number of targets marked) only present little information about users’ underlying cognitive strategies and may fail to reflect the user’s true intent. As understanding users’ intentions is critical to providing appropriate cognitive aids to enhance task performance, a Hidden Markov Model (HMM) is used to examine operators’ underlying cognitive intent and identify the unobservable cognitive states. The HMM results demonstrate fundamental differences among the queuing mechanisms and reliability conditions. The findings suggest that HMM can be helpful in investigating the use of human cognitive resources under multitasking environments
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