353 research outputs found
Evaluating the Catalytic Performance of La1-xCexNi1-yZnyO3 Nanostructure Perovskites in the Carbon Dioxide Reforming of Methane
AbstractIn this research nanostructure perovskites La1-xCexNi1-yZnyO3 were prepared by sol-gel auto-combustion method and their application were evaluated for methane reforming with carbon dioxide and syngas production. Catalysts were designed by Response Surface Method (RSM) based on central composite design (CCD) with three factors of catalyst characteristics, x, y and Tc. The prepared catalysts were examined in methane reforming process at 750 ˚C temperature and atmospheric pressure. Analysis of variance (ANOVA) showed that parameters don’t have any linear effect on catalytic activity and their effect is proportional to square form. Among this investigated parameters, Ni content effect is considerable and calcination temperature (Tc) has a partial effect. In this research R2 value was 94.88%. The optimum catalyst which determined by RSM was La0.60Ce0.40Ni0.81Zn0.19O3 in 747 ˚C calcination temperature that corresponds to empirical result. The XRD characterization of optimum catalyst showed that perovskite catalyst was formed in rhombohedra phase with nanostructure crystals and the SEM of optimum catalyst confirmed the nano scale of prepared particles
A Combination of Metabolomics and Machine Learning Results in the Identification of a New Cyst Nematode Hatching Factor
A Combination of Metabolomics and Machine Learning Results in the Identification of a New Cyst Nematode Hatching Factor
Potato Cyst Nematodes (PCNs) are an economically important pest for potato growers. A crucial event in the life cycle of the nematode is hatching, after which the juvenile will move toward the host root and infect it. The hatching of PCNs is induced by known and unknown compounds in the root exudates of host plant species, called hatching factors (HFs, induce hatching independently), such as solanoeclepin A (solA), or hatching stimulants (HSs, enhance hatching activity of HFs). Unraveling the identity of unknown HSs and HFs and their natural variation is important for the selection of cultivars that produce low amounts of HFs and HSs, thus contributing to more sustainable agriculture. In this study, we used a new approach aimed at the identification of new HFs and HSs for PCNs in potato. Hereto, root exudates of a series of different potato cultivars were analyzed for their PCN hatch-inducing activity and their solA content. The exudates were also analyzed using untargeted metabolomics, and subsequently the data were integrated using machine learning, specifically random forest feature selection, and Pearson’s correlation testing. As expected, solA highly correlates with hatching. Furthermore, this resulted in the discovery of a number of metabolite features present in the root exudate that correlate with hatching and solA content, and one of these is a compound of m/z 526.18 that predicts hatching even better than solA with both data methods. This compound’s involvement in hatch stimulation was confirmed by the fractionation of three representative root exudates and hatching assays with the resulting fractions. Moreover, the compound shares mass fragmentation similarity with solA, and we therefore assume it has a similar structure. With this work, we show that potato likely produces a solA analogue, and we contribute to unraveling the hatch-inducing cocktail exuded by plant roots
Updates in Hospital Palliative Care
Background: This review critiques recent palliative care (PC) literature with likelihood of impacting general hospital practice in order to help address the PC needs of patients. Methods: Articles published between January and December 2018 were identified through hand-search of leading PC journals and MEDLINE search. The final ten selected articles were determined by consensus based on scientific rigor, relevance to general hospital medicine, and impact to practice. Results: Key findings include: Early PC interventions reduced healthcare costs; Prognostic awareness of surrogates of patients with advanced dementia was associated with reduced burdensome interventions; Care transitions, especially in the last 3 days of life, can be detrimental to caregivers' well-being and perceptions of care; Haloperidol was effective for treatment of nausea and vomiting without untoward effects; Antipsychotics did not improve delirium symptoms in hospitalized patients; A fan directed to the face improved dyspnea; Disparities in advance directive completion disappeared when equal opportunities were given; Improving communication with families of critically ill patients improved perceptions of patient-centered care; Communication-priming tools improved the quality and documentation of goals of care conversations; Discussing prognosis did not harm the patient-provider relationship. Conclusion: Recent PC research affirmed the importance of PC delivery to patients with life-limiting illness and provided important guidance to hospitalists on symptom management, advance care planning, and communication.Rachel D. Havyer (1*), Nauzley Abedini (2), Robert L. Jayes (3), Brenda Matti-Orozco (4), Daniel H. Pomerantz (5), Aziz A. Ansari (6); 1. Division of Community Internal Medicine, Mayo Clinic. 2. Division of Palliative Medicine, University of California San Francisco. 3. Division of Geriatrics and Palliative Medicine, George Washington University Medical Faculty Associates. 4. Division of General Internal Medicine and Palliative Medicine, Morristown Medical Center, Atlantic Health System. 5. Department of Medicine, Montefiore New Rochelle Hospital. 6. Division of Hospital Medicine, Loyola University Medical CenterIncludes bibliographical reference
Simulation of transport in laterally gated junctionless transistors fabricated by local anodization with an atomic force microscope
In this paper, we have investigated the characteristics and transport features of junctionless lateral gate transistors via measurement and simulations. The transistor is fabricated using an atomic force microscopy (AFM) nanolithography technique on silicon-on-insulator (SOI) wafer. This work develops our previous examination of the device operation by using 3D numerical simulations to offer a better understanding of the origin of the transistor operation. We compare the experimental measurements and simulation results in the transfer characteristic and drain conductance. We also explore the behavior of the device in on and off states based on the variation of majority and minority carriers' density, electric-field components, and recombination/generation rate of carriers in the active region of the device. We show that the device is a normally on device that can force the current through a depleted region (off state) and uses bulk conduction instead of surface conduction. We also found that due to the lateral gate design, low-doped channel, and lack of the gate oxide the electrostatic squeezing of the channel effectively forces the device into the off state, but the current improvement by accumulation of carriers is not significant
Pinch-off effect in p-type double gate and single gate junctionless silicon nanowire transistor fabricated by atomic force microscopy nanolithography
The spark of aggressive scaling of transistors was started after the Moors law on prediction of device dimensions. Recently, among the several types of transistors, junctionless transistors were considered as one of the promising alternative for new generation of nanotransistors. In this work, we investigate the pinch-off effect in double gate and single gate junctionless lateral gate transistors. The transistors are fabricated on lightly doped (1015) p-type Silicon-on-insulator wafer by using an atomic force microscopy nanolithography technique. The transistors are normally on state devices and working in depletion mode. The behavior of the devices confirms the normal behavior of the junctionless transistors. The pinch-off effect appears at VG +2.0 V and VG +2.5 V for fabricated double gate and single structure, respectively. On state current is in the order of 10-9 (A) for both structures due to low doping concentration. The single gate and double gate devices exhibit an Ion/Ioff of approximately 105 and 106, respectively
Lessons learned from the introduction of autonomous monitoring to the EUVE science operations center
The University of California at Berkeley's (UCB) Center for Extreme Ultraviolet Astrophysics (CEA), in conjunction with NASA's Ames Research Center (ARC), has implemented an autonomous monitoring system in the Extreme Ultraviolet Explorer (EUVE) science operations center (ESOC). The implementation was driven by a need to reduce operations costs and has allowed the ESOC to move from continuous, three-shift, human-tended monitoring of the science payload to a one-shift operation in which the off shifts are monitored by an autonomous anomaly detection system. This system includes Eworks, an artificial intelligence (AI) payload telemetry monitoring package based on RTworks, and Epage, an automatic paging system to notify ESOC personnel of detected anomalies. In this age of shrinking NASA budgets, the lessons learned on the EUVE project are useful to other NASA missions looking for ways to reduce their operations budgets. The process of knowledge capture, from the payload controllers for implementation in an expert system, is directly applicable to any mission considering a transition to autonomous monitoring in their control center. The collaboration with ARC demonstrates how a project with limited programming resources can expand the breadth of its goals without incurring the high cost of hiring additional, dedicated programmers. This dispersal of expertise across NASA centers allows future missions to easily access experts for collaborative efforts of their own. Even the criterion used to choose an expert system has widespread impacts on the implementation, including the completion time and the final cost. In this paper we discuss, from inception to completion, the areas where our experiences in moving from three shifts to one shift may offer insights for other NASA missions
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