Docking control for probe-drogue refueling: An additive-state-decomposition-based output feedback iterative learning control method

Designing a controller for the docking maneuver in Probe-Drogue Refueling (PDR) is an important but challenging task, due to the complex system model and the high precision requirement. In order to overcome the disadvantage of only feedback control, a feedforward control scheme known as Iterative Learning Control (ILC) is adopted in this paper. First, Additive State Decomposition (ASD) is used to address the tight coupling of input saturation, nonlinearity and the property of NonMinimum Phase (NMP) by separating these features into two subsystems (a primary system and a secondary system). After system decomposition, an adjoint-type ILC is applied to the Linear Time-Invariant (LTI) primary system with NMP to achieve entire output trajectory tracking, whereas state feedback is used to stabilize the secondary system with input saturation. The two controllers designed for the two subsystems can be combined to achieve the original control goal of the PDR system. Furthermore, to compensate for the receiver-independent uncertainties, a correction action is proposed by using the terminal docking error, which can lead to a smaller docking error at the docking moment. Simulation tests have been carried out to demonstrate the performance of the proposed control method, which has some advantages over the traditional derivative-type ILC and adjoint-type ILC in the docking control of PDR

Arginine-Facilitated Isomerization: Radical-Induced Dissociation of Aliphatic Radical Cationic Glycylarginyl(iso)leucine Tripeptides

The gas phase fragmentations of aliphatic radical cationic glycylglycyl­(iso)­leucine tripeptides ([G•G­(L/I)]+), with well-defined initial locations of the radical centers at their N-terminal α-carbon atoms, are significantly different from those of their basic glycylarginyl­(iso)­leucine ([G•R­(L/I)]+) counterparts; the former lead predominantly to [b2 – H]•+ fragment ions, whereas the latter result in the formation of characteristic product ions via the losses of •CH­(CH3)2 from [G•RL]+ and •CH2CH3 from [G•RI]+ through Cβ–Cγ side-chain cleavages of the (iso)­leucine residues, making these two peptides distinguishable. The α-carbon-centered radical at the leucine residue is the key intermediate that triggers the subsequent Cβ–Cγ bond cleavage, as supported by the absence of •CH­(CH3)2 loss from the collision-induced dissociation of [G•RLα‑Me]+, a radical cation for which the α-hydrogen atom of the leucine residue had been substituted by a methyl group. Density functional theory calculations at the B3LYP 6-31++G­(d,p) level of theory supported the notion that the highly basic arginine residue could not only increase the energy barriers against charge-induced dissociation pathways but also decrease the energy barriers against hydrogen atom transfers in the GR­(L/I) radical cations by ∼10 kcal mol–1, thereby allowing the intermediate precursors containing α- and γ-carbon-centered radicals at the (iso)­leucine residues to be formed more readily prior to promoting subsequent Cβ–Cγ and Cα–Cβ bond cleavages. The hydrogen atom transfer barriers for the α- and γ-carbon-centered GR­(L/I) radical cations (roughly in the range 29–34 kcal mol–1) are comparable with those of the competitive side-chain cleavage processes. The transition structures for the elimination of •CH­(CH3)2 and •CH2CH3 from the (iso)­leucine side chains possess similar structures, but slightly different dissociation barriers of 31.9 and 34.0 kcal mol–1, respectively; the energy barriers for the elimination of the alkenes CH2CH­(CH3)2 and CH3CHCHCH3 through Cα–Cβ bond cleavages of γ-carbon-centered radicals at the (iso)­leucine side chains are 29.1 and 32.8 kcal mol–1, respectively

Fully Automated Multidimensional Reversed-Phase Liquid Chromatography with Tandem Anion/Cation Exchange Columns for Simultaneous Global Endogenous Tyrosine Nitration Detection, Integral Membrane Protein Characterization, and Quantitative Proteomics Mapping in Cerebral Infarcts

Protein tyrosine nitration (PTN) is a signature hallmark of radical-induced nitrative stress in a wide range of pathophysiological conditions, with naturally occurring abundances at substoichiometric levels. In this present study, a fully automated four-dimensional platform, consisting of high-/low-pH reversed-phase dimensions with two additional complementary, strong anion (SAX) and cation exchange (SCX), chromatographic separation stages inserted in tandem, was implemented for the simultaneous mapping of endogenous nitrated tyrosine-containing peptides within the global proteomic context of a <i>Macaca fascicularis</i> cerebral ischemic stroke model. This integrated RP–SA­(C)­X–RP platform was initially benchmarked through proteomic analyses of <i>Saccharomyces cerevisiae</i>, revealing extended proteome and protein coverage. A total of 27 144 unique peptides from 3684 nonredundant proteins [1% global false discovery rate (FDR)] were identified from <i>M. fascicularis</i> cerebral cortex tissue. The inclusion of the S­(A/C)­X columns contributed to the increased detection of acidic, hydrophilic, and hydrophobic peptide populations; these separation features enabled the concomitant identification of 127 endogenous nitrated peptides and 137 transmembrane domain-containing peptides corresponding to integral membrane proteins, without the need for specific targeted enrichment strategies. The enhanced diversity of the peptide inventory obtained from the RP–SA­(C)­X–RP platform also improved analytical confidence in isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analyses

Fully Automated Multidimensional Reversed-Phase Liquid Chromatography with Tandem Anion/Cation Exchange Columns for Simultaneous Global Endogenous Tyrosine Nitration Detection, Integral Membrane Protein Characterization, and Quantitative Proteomics Mapping in Cerebral Infarcts

Protein tyrosine nitration (PTN) is a signature hallmark of radical-induced nitrative stress in a wide range of pathophysiological conditions, with naturally occurring abundances at substoichiometric levels. In this present study, a fully automated four-dimensional platform, consisting of high-/low-pH reversed-phase dimensions with two additional complementary, strong anion (SAX) and cation exchange (SCX), chromatographic separation stages inserted in tandem, was implemented for the simultaneous mapping of endogenous nitrated tyrosine-containing peptides within the global proteomic context of a <i>Macaca fascicularis</i> cerebral ischemic stroke model. This integrated RP–SA­(C)­X–RP platform was initially benchmarked through proteomic analyses of <i>Saccharomyces cerevisiae</i>, revealing extended proteome and protein coverage. A total of 27 144 unique peptides from 3684 nonredundant proteins [1% global false discovery rate (FDR)] were identified from <i>M. fascicularis</i> cerebral cortex tissue. The inclusion of the S­(A/C)­X columns contributed to the increased detection of acidic, hydrophilic, and hydrophobic peptide populations; these separation features enabled the concomitant identification of 127 endogenous nitrated peptides and 137 transmembrane domain-containing peptides corresponding to integral membrane proteins, without the need for specific targeted enrichment strategies. The enhanced diversity of the peptide inventory obtained from the RP–SA­(C)­X–RP platform also improved analytical confidence in isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analyses

Data for "Nitrogen enrichment induces more plant species loss under drier conditions"

Nitrogen (N) deposition is a major driver of plant species loss worldwide. However, what regulates N-driven species loss remains unclear. Based on a 7-year field experiment on the Qinghai-Tibetan Plateau, we found that the impact of N addition on plant species richness strongly depended on precipitation. During experimental years with lower precipitation, N addition induced more species loss. The main underlying mechanism was that lower precipitation stimulated soil inorganic N accumulation under N addition, resulting in stronger competitive exclusion and ammonium toxicity in plant communities. These site observations were complemented by a global synthesis derived from 45 N addition experiments, showing N-induced more species loss in dry than in wet ecosystems. Given the importance of plant species richness in supporting ecosystem functioning and stability, our findings suggest that ecosystems during drought periods or in arid areas are particularly sensitive to N deposition, having important implications for their management and conservation.</p

Online Two-Dimensional Porous Graphitic Carbon/Reversed Phase Liquid Chromatography Platform Applied to Shotgun Proteomics and Glycoproteomics

A novel fully automatable two-dimensional liquid chromatography (2DLC) platform has been integrated into a modified commercial off-the-shelf LC instrument, incorporating porous graphitic carbon (PGC) separation and conventional low-pH reversed-phase (RP) separation for both proteomics and N-glycomics analyses; the dual-trap column configuration of this platform offers desirable high-throughput analyses with almost no idle time, in addition to a miniaturized setup and simplified operation. The total run time per analysis was only 19 h when using eight PGC fractions for unattended large-scale qualitative and quantitative proteomic analyses; the identification of 2678 nonredundant proteins and 11 984 unique peptides provided one of the most comprehensive proteome data sets for primary cerebellar granule neurons (CGNs). The effect of pH on the PGC column was investigated for the first time to improve the hydrophobic peptide coverage; the performance of the optimized system was first benchmarked using tryptic digests of Saccharomyces cerevisiae cell lysates and then evaluated through duplicate analyses of Macaca fascicularis cerebral cortex lysates using isobaric tags for relative and absolute quantitation (iTRAQ) technology. An additional plug-and-play PGC module functioned in a complementary manner to recover unretained hydrophilic solutes from the low-pH RP column; synchronization of the fractionations between the PGC-RP system and the PGC module facilitated simultaneous analyses of hydrophobic and hydrophilic compounds from a single sample injection event. This methodology was applied to perform, for the first time, detailed glycomics analyses of Macaca fascicularis plasma, resulting in the identification of a total 130 N-glycosylated plasma proteins, 705 N-glycopeptides, and 254 N-glycosylation sites

Online Two-Dimensional Porous Graphitic Carbon/Reversed Phase Liquid Chromatography Platform Applied to Shotgun Proteomics and Glycoproteomics

A novel fully automatable two-dimensional liquid chromatography (2DLC) platform has been integrated into a modified commercial off-the-shelf LC instrument, incorporating porous graphitic carbon (PGC) separation and conventional low-pH reversed-phase (RP) separation for both proteomics and <i>N</i>-glycomics analyses; the dual-trap column configuration of this platform offers desirable high-throughput analyses with almost no idle time, in addition to a miniaturized setup and simplified operation. The total run time per analysis was only 19 h when using eight PGC fractions for unattended large-scale qualitative and quantitative proteomic analyses; the identification of 2678 nonredundant proteins and 11 984 unique peptides provided one of the most comprehensive proteome data sets for primary cerebellar granule neurons (CGNs). The effect of pH on the PGC column was investigated for the first time to improve the hydrophobic peptide coverage; the performance of the optimized system was first benchmarked using tryptic digests of Saccharomyces cerevisiae cell lysates and then evaluated through duplicate analyses of Macaca fascicularis cerebral cortex lysates using isobaric tags for relative and absolute quantitation (iTRAQ) technology. An additional plug-and-play PGC module functioned in a complementary manner to recover unretained hydrophilic solutes from the low-pH RP column; synchronization of the fractionations between the PGC-RP system and the PGC module facilitated simultaneous analyses of hydrophobic and hydrophilic compounds from a single sample injection event. This methodology was applied to perform, for the first time, detailed glycomics analyses of Macaca fascicularis plasma, resulting in the identification of a total 130 <i>N</i>-glycosylated plasma proteins, 705 <i>N</i>-glycopeptides, and 254 <i>N</i>-glycosylation sites

Multiscale Confinement Engineering for Boosting Overall Water Splitting by One-Step Stringing of a Single Atom and a Janus Nanoparticle within a Carbon Nanotube

Enzyme-mimicking confined catalysis has attracted great interest in heterogeneous catalytic systems that can regulate the geometric or electronic structure of the active site and improve its performance. Herein, a liquid-assisted chemical vapor deposition (LCVD) strategy is proposed to simultaneously confine the single-atom Ru sites onto sidewalls and Janus Ni/NiO nanoparticles (NPs) at the apical nanocavities to thoroughly energize the N-doped carbon nanotube arrays (denoted as Ni/NiO@Ru-NC). The bifunctional Ni/NiO@Ru-NC electrocatalyst exhibits overpotentials of 88 and 261 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at 100 mA cm–2 in alkaline solution, respectively, all ranking the top tier among the carbon-supported metal-based electrocatalysts. Moreover, once integrated into an anion-exchange membrane water electrolysis (AEMWE) system, Ni/NiO@Ru-NC can act as an efficient and robust bifunctional electrocatalyst to operate stably for 50 h under 500 mA cm–2. Theoretical calculations and experimental exploration demonstrate that the confinement of Ru single atoms and Janus Ni/NiO NPs can regulate the electron distribution with strong orbital couplings to activate the NC nanotube from sidewall to top, thus boosting overall water splitting

Multiscale Confinement Engineering for Boosting Overall Water Splitting by One-Step Stringing of a Single Atom and a Janus Nanoparticle within a Carbon Nanotube

Enzyme-mimicking confined catalysis has attracted great interest in heterogeneous catalytic systems that can regulate the geometric or electronic structure of the active site and improve its performance. Herein, a liquid-assisted chemical vapor deposition (LCVD) strategy is proposed to simultaneously confine the single-atom Ru sites onto sidewalls and Janus Ni/NiO nanoparticles (NPs) at the apical nanocavities to thoroughly energize the N-doped carbon nanotube arrays (denoted as Ni/NiO@Ru-NC). The bifunctional Ni/NiO@Ru-NC electrocatalyst exhibits overpotentials of 88 and 261 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at 100 mA cm–2 in alkaline solution, respectively, all ranking the top tier among the carbon-supported metal-based electrocatalysts. Moreover, once integrated into an anion-exchange membrane water electrolysis (AEMWE) system, Ni/NiO@Ru-NC can act as an efficient and robust bifunctional electrocatalyst to operate stably for 50 h under 500 mA cm–2. Theoretical calculations and experimental exploration demonstrate that the confinement of Ru single atoms and Janus Ni/NiO NPs can regulate the electron distribution with strong orbital couplings to activate the NC nanotube from sidewall to top, thus boosting overall water splitting