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A polymorph of glycyl-L-alanine HI.H2O is synthesized from chiral cyclo-glycyl-L-alanine dipeptide. The dipeptide is known to show molecular flexibility in different environments, which leads to polymorphism. The crystal structure of the glycyl-L-alanine HI.H2O polymorph is determined at room temperature and indicates that the space group is polar (P21), with two molecules per unit cell and unit cell parameters a = 7.747 Å, b = 6.435 Å, c = 10.941 Å, α = 90°, β = 107.53(3)°, γ = 90° and V = 520.1(7) Å3. Crystallization in the polar point group 2, with one polar axis parallel to the b axis, allows pyroelectricity and optical second harmonic generation. Thermal melting of the glycyl-L-alanine HI.H2O polymorph starts at 533 K, close to the melting temperature reported for cyclo-glycyl-L-alanine (531 K) and 32 K lower than that reported for linear glycyl-L-alanine dipeptide (563 K), suggesting that although the dipeptide, when crystallized in the polymorphic form, is not anymore in its cyclic form, it keeps a memory of its initial closed chain and therefore shows a thermal memory effect. Here, we report a pyroelectric coefficient as high as 45 µC/m2K occurring at 345 K, one order of magnitude smaller than that of semi-organic ferroelectric triglycine sulphate (TGS) crystal. Moreover, the glycyl-L-alanine HI.H2O polymorph displays a nonlinear optical effective coefficient of 0.14 pm/V, around 14 times smaller than the value from a phase-matched inorganic barium borate (BBO) single crystal. The new polymorph displays an effective piezoelectric coefficient equal to deff=280pCN−1, when embedded into electrospun polymer fibers, indicating its suitability as an active system for energy harvesting.

Described here is a titanocene‐catalyzed reaction for the synthesis of acetals and hemiaminals from benzylic ethers and benzylic amines, respectively, with pendant epoxides. The reaction proceeds by catalysis in single‐electron steps. The oxidative addition comprises an epoxide opening. An H‐atom transfer, to generate a benzylic radical, serves as a radical translocation step, and an organometallic oxygen rebound as a reductive elimination. The reaction mechanism was studied by high‐level dispersion corrected hybrid functional DFT with implicit solvation. The low‐energy conformational space was searched by the efficient CREST program. The stereoselectivity was deduced from the lowest lying benzylic radical structures and their conformations are controlled by hyperconjugative interactions and steric interactions between the titanocene catalyst and the aryl groups of the substrate. An interesting mechanistic aspect is that the oxidation of the benzylic center occurs under reducing conditions., Oxidations with reducing agents? Fact and not fiction in a reaction featuring titanocene(III) catalysis, H‐atom transfer, and an organometallic oxygen rebound. Acetals and hemiaminals can be readily prepared from benzylic ethers and amines, respectively, under mild reaction conditions and in high yields. The structures of the radical intermediates were elucidated by the CREST program.

In this paper, a new topology of a Fractional Order PID (FOPID) controller is proposed to control a boost DC-DC converter with minimum over/undershoot. The fractional controller parameters are tuned using a genetic algorithm (GA) with a combined cost function composed of the Integral of Time-Weighted Absolute Error (ITAE) and the Integral of Time-Weighted Square Error (ITSE). Despite adding moderate complexity to the control structure, the simulation results reveal that the GA-based FOPID controller tuning provided better performance for the setpoint tracking both under load variations and parameters deviation due to the prolonged use. The proposed FOPID shows a wide operational range concerning load disturbances, and capacitance/inductance deviations of ±30% and ±50% from nominal values, achieving functionality and voltage stability even with output power 50% higher than the converter power specification. The assessment was made considering operation in voltage mode and the performance was compared to conventional Proportional-Integral (PI), Type II and current mode controllers. Finally, a fuzzy fractional-order PID (FFOPID) was designed to outperform the FOPID during disturbances in the control variable.

Yeast amino acid transporters of the APC superfamily are responsible for the proton motive force‐driven uptake of amino acids into the cell, which for most secondary transporters is a reversible process. The l‐lysine proton symporter Lyp1 of Saccharomyces cerevisiae is special in that the Michaelis constant from out‐to‐in transport ( Kmout→in ) is much lower than Kmin→out , which allows accumulation of l‐lysine to submolar concentration. It has been proposed that high intracellular lysine is part of the antioxidant mechanism of the cell. The molecular basis for the unique kinetic properties of Lyp1 is unknown. We compared the sequence of Lyp1 with APC para‐ and orthologues and find structural features that set Lyp1 apart, including differences in extracellular loop regions. We screened the extracellular loops by alanine mutagenesis and determined Lyp1 localization and activity and find positions that affect either the localization or activity of Lyp1. Half of the affected mutants are located in the extension of extracellular loop 3 or in a predicted α‐helix in extracellular loop 4. Our data indicate that extracellular loops not only connect the transmembrane helices but also serve functionally important roles., We performed alanine‐scanning mutagenesis of the extracellular loops of the yeast lysine transporter Lyp1. We find positions that affect either the localization or activity of Lyp1. Half of the affected mutants are located in the extension of extracellular loop 3 or in a predicted α‐helix in extracellular loop 4. We conclude that extracellular loops of amino acid transporters of the APC superfamily serve functionally important roles.

BACKGROUND: Sarcopenia is associated with impaired short- and long-term outcomes in gastrointestinal cancers. Whether sarcopenia is associated with impaired survival after local therapy of Colorectal Cancer Liver Metastases (CRLM) remains controversial. This study aimed to determine the influence of sarcopenia on long-term outcomes after curative-intent therapy for CRLM.METHODS: Patients undergoing local therapy for CRLM between 2003 and 2019 were retrospectively analyzed using the skeletal muscle index at the level of the third lumbar vertebra as an indicator of sarcopenia. Factors associated with overall (OS) and disease-free (DFS) survival were analyzed using univariable and multivariable cox regression.RESULTS: In total 213/465 patients (46%) were considered sarcopenic. Sarcopenic patients had no impaired 5-year OS or DFS compared to non-sarcopenic patients, 38% vs 44% (p = 0.153) and 19 vs 23% (p = 0.339) respectively. Sarcopenia was not associated with impaired OS (HR = 1.11, 95%CI = 0.85-1.46, p = 0.43) or DFS (HR = 0.99, 95%CI = 0.77-1.28, p = 0.96) in multivariable analysis. There were no significant differences in postoperative complications (p = 0.47), the incidence (p = 0.65) and treatment (p = 0.37) of recurrent metastases. Five-year OS after resection for recurrences was 14% (sarcopenic) and 22% (non-sarcopenic) p 0.716.CONCLUSION: Sarcopenia assessed by computed tomography was not associated with impaired survival outcomes in the group of CRLM patients overall.

This study presents a fine scale simulation approach to assess the representativity of ammonia (NH3) measurements in proximity of an emission source. Close proximity to emission sources (3 molar fraction and flux. Measurement sites should therefore be located a significant distance from emission sources, but such requirements are poorly defined and can be difficult to meet in densely agricultural regions. This study presents a consistent criterium to assess the regional representativity of NH3 measurements in proximity of an emission source, calculating variables that quantify the NH3 plume dispersion using a series of numerical experiments at a fine resolution (20 m). Our fine scale simulation framework with explicitly resolved turbulence enables us to distinguish between the background NH3 and the emission plume, including realistic representations of NH3 deposition and chemical gas-aerosol transformations. We introduce the concept of blending-distance, based on the calculation of turbulent fluctuations, to systematically analyze the impact of the emission plume on simulated measurements, relative to this background NH3. This sensitivity analysis includes systematic experiments varying meteorological factors, emission/deposition and NH3 dependences. Considering these sensitivities, we find that NH3 measurements should be located at a minimum distance of 0.5–2.5 km and 1–3.5 km from an emission source, for NH3 molar fraction and flux measurements respectively. The simulation framework presented here can easily be adapted to local conditions and paves the way for future ammonia research at high spatio-temporal resolution.

This study presents a fine scale simulation approach to assess the representativity of ammonia (NH3) measurements in proximity of an emission source. Close proximity to emission sources (

We describe a combination of catalysts that allows the coupling of titanocene(III) catalysis with photoredox catalysis. Oxidation of radical intermediates by a photoredox catalyst opens novel catal...

The recent evolutions in the convergence of QKD and classical communication systems are described, together with the relevance of SDN as a suitable approach for a real integration between QKD and WDM networks. Preliminary experimental results on a discrete-variable QKD prototype working in the O-band co-propagating with 40 50-GHz C-band information channels are reported, showing the capabilities of QKD in short/medium reach optical networks.

Modern communication networks can be flexibly shaped and controlled using Software Defined Networking (SDN) paradigm. However, besides unprecedented functional benefits, this solution exploits an architectural single point of failure. Securing the communication among SDN functional element is therefore a critical requirement for improving the network reliability. A novel approach to secure communications is provided by Quantum Key Distribution (QKD) that is a physical layer technology capable to securely deliver symmetric encryption keys leveraging on quantum physic properties. Our research demonstrates how to provide unconditionally secure communication at SDN level dramatically improving the reliability of the communication network itself.

We investigate diurnal variability of the atmospheric ammonia (NH3) budget over unfertilized grassland by combining observations with a conceptual atmospheric boundary layer model. Our combined approach of diurnal observations and modeling enables us to identify the contribution of the four governing processes to the NH3 diurnal cycle: surface-atmosphere exchange, entrainment, advection and chemical gas-aerosol transformations. The observations contain new NH3 flux and molar fraction measurements obtained using the Differential Optical Absorption Spectroscopy (DOAS) remote sensing technique, eliminating problems related to inlet tubing. Using strict filter criteria, 22 days with clear-sky summer conditions are selected. From this selection, we analyze a single representative day characterized by prototypical convective boundary layer conditions, using the boundary layer model constrained by meteorological observations. We design two numerical experiments to study the NH3 diurnal variability and the individual contributions of the processes governing the ammonia budget. These experiments only differ in their representation of the NH3 surface exchange. First, a fitted function through the observed NH3 flux is prescribed to the model. In the second numerical experiment, the surface flux is solved following the DEPosition of Acidifying Compounds (DEPAC) parameterization. With a prescribed surface flux, the modeled NH3 molar fraction closely fits the observations. Two regimes are identified in the NH3 diurnal cycle: the morning, where boundary layer dynamics dominate the budget through entrainment, and the afternoon, where multiple processes are of importance. A similarly close fit to the observed molar fraction is achieved in the second experiment, but we identify a mismatch between the observed and parameterized NH3 surface flux. As a result, the model requires an unrealistic budget representation to achieve this close fit, e.g. high free tropospheric NH3. Our findings on the NH3 budget, based on integrating modeling and observations, paves the way for future research on the NH3 surface-atmosphere exchange at the subdaily scales.

En av de vanskeligste aspektene ved ˚a reprodusere menneskelig atferd i robotikk er ˚a utføre ikke-prehensile (ikke-gripende) objektmanipulering. Dersom roboter skal kunne integreres i en menneskeskapt verden, m˚a de være i stand til ˚a utføre slike komplekse aktiviteter. Denne oppgaven tar sikte p˚a ˚a introdusere en ny stabiliserende kontroller til Sommerfugl roboten gitt at den transverse lineariserte dynamikken er funnet. Systemet best˚aende av en ˚atteformet ramme med en ball som rullet p˚a toppen ble foresl˚att som et standardeksempel for utvikling av nye teknikker innen ikke-prehensil manipulasjon. Mens tidligere stabiliseringsmetoder er avhengig av en lineær nominell kontroller basert p˚a stabiliserende løsningen av den periodiske Ricatti differensialligningen (PRDE), vil denne oppgaven introdusere en ”sliding mode control” for ˚a h˚andtere uunng˚aelige forstyrrelser i systemet. Arbeidet presentert i denne oppgaven bruker en ”virtual holonomic constraint” tilnærming. Her brukes en skalar-variabel kjent som en bevegelsesgenerator i et geometrisk forhold kjent som en virtual holonomic constraint for ˚a redusere systemets kompleksitet ved ˚a holde den geometriske relasjonen uforanderlig gjennom en feedback kontroller. Den nominelle banen for det ulineære systemet kan deretter avledes ut fra dynamikken til bevegelsesgeneratoren. Stabiliseringsmetoden bruker den velkjente ekvivalensen mellom et uineært systems lokale, stabile oppførsel og dets lineariserte systems lokale, stabile oppførsel. Et sett med transverse koordinater hvis opprinnelse tilsvarer den nominelle banen, kan deretter lineariseres og stabiliseres ved hjelp av en feedback regulator slik at det resulterende ulineære systemet ogs˚a blir stabilisert. P˚a grunnlag av den transverse lineariseringen vil det utformes to alternative sliding mode kontrollere. Den første metoden er enklere og er basert p˚a Lyapunov-teori, der det vil bli etablert kontrollov som muliggjør en endelig tidskonvergens mot en s˚akalt glidende overflate (som samsvarer med den nominelle oppførselen). For den andre teknikken vil det opprettes et reelt ”subspace” av det lineariserte systemet før dens ”annihilator”, hvis samdimensjoner tilsvarer antall kontrollinnganger, brukes i en svitchfunksjon for kontrolleren. Fordi begge metodene bruker PRDEs stabiliserende løsning, vil ”semi-definite” programmering brukes til ˚a finne en tilnærming. Det ble p˚avist at den første metoden raskt konvergerte mot den nominelle banen for nominelle systemparametere ved numeriske simuleringer, mens for de forstyrrede parametrene viste en betydelig stasjonær feil, men likevel konvergerte mot banen. Den andre metoden resulterte ikke i noen vellykket stabilisering, som var forventet gitt at det ikke ble funnet et subspace som oppfylte de nødvendige betingelsene One of the most challenging aspects of reproducing human behavior in robotics is performing non-prehensile (non-gripping) object manipulation. Robots must be able to move and perform complex activities if they are to be integrated into a human-built world. This paper aims to introduce a new stabilizing controller to the Butterfly Robot, given that the transverse linearized dynamics have been found. The system consisting of a figure eightshaped frame with a ball rolling on top was proposed as a benchmark example for developing new techniques within the field of non-prehensile manipulation. While previous stabilizing methods rely on a linear nominal feedback controller based on the stabilizing solution of the periodic Ricatti differential equation (PRDE), this paper will introduce a sliding mode controller to deal with unavoidable perturbations of the system. The work presented in this paper uses the virtual holonomic constraint approach. Here, a scalar variable known as a motion generator is utilized in a geometric relation known as a virtual holonomic constraint to reduce the system’s complexity by keeping the geometric relation invariant through a feedback controller. The nominal trajectory for the nonlinear system can then be derived based on the dynamics of the motion generator. The stabilization method makes use of the well-known equivalence between a nonlinear system’s local, stable behavior and its linearized system’s local, stable behavior. A set of transverse coordinates whose origin corresponds to the nominal trajectory can then be linearized and stabilized using a feedback controller such that its resulting nonlinear system will be stabilized as well. Based on the transverse linearization, two alternative sliding mode controller architectures will be designed. The first method is simpler and is based on Lyapunov theory. A control law will be established that enables finite-time convergence towards a so-called sliding surface (that matches the nominal behavior). For the second technique, a real invariant subspace of the linearization will be created before its annihilator, whose co-dimensions equals the number of control input, is used in a switching function for the controller. Because both methods use the PRDE’s stabilizing solution, semi-definite programming will be used to find an approximation. The first method was proven to swiftly converge towards the nominal trajectory for nominal system parameters by numerical simulations. In contrast, the perturbed parameters showed a considerable stationary error but still converged towards the trajectory. The second method did not result in any successful stabilization, which was expected given that the found subspace failed to satisfy the required conditions, motivating for further work.

SBES RESEARCH TRACK -Continuous integration (CI) is a process widely used in projects of different types and sizes, generally aimed at improving development and also ensuring the quality of the software. However, some bad practices can mitigate or invalidate the beneficial effects of CI. In this context, we present an initial study to analyze CI bad practices in two closed-source projects. The study had as main research questions: (i) the frequency of CI bad practices in projects, (ii) the time that builds failures remain unresolved in projects, and (iii) the effects of CI bad practices on software health from the perspective of developers and project managers. For this, we carried out a mapping of the existence of bad practices through a questionnaire directed to the projects team. Also, it was realized the analysis of the pipeline history of the projects. Our findings indicate that the most common CI bad practices are related to improper management of the CI repository, and defective builds usually take a long time to fix. Besides, we found that the difficulties resulting from CI bad practices promote an increase in the development cost and reduction of software quality assurance.

We present a combined electrochemical, kinetic, and synthetic study with a novel and easily accessible class of titanocene catalysts for catalysis in single-electron steps. The tailoring of the electronic properties of our Cp2 TiX-catalysts that are prepared in situ from readily available Cp2 TiX2 is achieved by varying the anionic ligand X. Of the complexes investigated, Cp2 TiOMs proved to be either equal or substantially superior to the best catalysts developed earlier. The kinetic and thermodynamic properties pertinent to catalysis have been determined. They allow a mechanistic understanding of the subtle interplay of properties required for an efficient oxidative addition and reduction. Therefore, our study highlights that efficient catalysts do not require the elaborate covalent modification of the cyclopentadienyl ligands.