Immune response stimulation to prevent infection progression may be an adjuvant to antimicrobial treatment. Lysophosphatidylcholine (LPC) is an immunomodulator involved in immune cell recruitment and ...activation. In this study, we aimed to evaluate the efficacy of LPC in combination with colistin, tigecycline, or imipenem in experimental murine models of peritoneal sepsis and pneumonia. We used Acinetobacter baumannii strain Ab9, which is susceptible to colistin, tigecycline, and imipenem, and multidrug-resistant strain Ab186, which is susceptible to colistin and resistant to tigecycline and imipenem. Pharmacokinetic and pharmacodynamic parameters for colistin, tigecycline, and imipenem and the 100% minimal lethal dose (MLD100) were determined for both strains. The therapeutic efficacies of LPC, colistin (60 mg/kg of body weight/day), tigecycline (10 mg/kg/day), and imipenem (180 mg/kg/day), alone or in combination, were assessed against Ab9 and Ab186 at the MLD100 in murine peritoneal sepsis and pneumonia models. The levels of pro- and anti-inflammatory cytokines, i.e., tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA) for the same experimental models after inoculating mice with the MLD of both strains. LPC in combination with colistin, tigecycline, or imipenem markedly enhanced the bacterial clearance of Ab9 and Ab186 from the spleen and lungs and reduced bacteremia and mouse mortality rates (P < 0.05) compared with those for colistin, tigecycline, and imipenem monotherapies. Moreover, at 4 h post-bacterial infection, Ab9 induced higher TNF-α and lower IL-10 levels than those with Ab186 (4 μg/ml versus 3 μg/ml P < 0.05 and 2 μg/ml versus 3.4 μg/ml P < 0.05, respectively). LPC treatment combined with colistin, tigecycline, or imipenem modestly reduced the severity of infection by A. baumannii strains with different resistance phenotypes compared to LPC monotherapy in both experimental models.
•Two nonlinear control schemes for a quadrotor carrying a payload attached by a cable are designed.•The asymptotic stability is guaranteed using the Lyapunov technique and La Salle’s invariance ...principle.•The controllers take advantage of the coupling existing between the vehicle movement and the payload swing.•The main advantage of the proposed control laws is its relatively easy and intuitive design.
Two novel nonlinear control schemes for Unmanned Aerial Vehicles (UAV) carrying a load and their comparative results are presented in this paper. The goal is to carry the load to a desired position, with oscillation attenuation along the trajectory. The proposed control structures are hierarchical schemes consisting of nonlinear controllers to stabilize the vehicle translational movements and the payload swing together with a well-known state-dependent differential Riccati equation controller to stabilize the rotational dynamics. We present new methodologies where two nonlinear controllers are proposed to obtain precise aerial vehicle positioning and efficient load oscillation reduction by exploiting the natural coupling between the horizontal quadcopter movement and the payload oscillation. It is shown that asymptotic stability can be guaranteed by the use of the Lyapunov approach and La Salle’s invariance principle. Numerical experiments were carried out to validate the nonlinear control behaviors where the results show improvements with respect to a strategy from the literature.
This paper presents a new approach of the continuous‐discrete observer design for a class of uncertain state‐affine non‐linear systems. A high‐gain observer redesign is developed and analysed under ...insightful conditions. The proposed observer estimates the state vector by using system output measurements with long sampling times. This result is achieved by considering a persistent excitation condition that can be validated online. The performance of the proposed algorithm is evaluated under time‐varying sampled measurements to estimate the friction factor of a pipeline where the case of noisy sampled output measurements is also considered.
We use molecular dynamics (MD) simulations to deform single crystal spherical carbon nanoparticles (NP), 4–45 nm diameter, with a hard, flat indenter, compressing along the 001 direction. There is no ...clear amorphization nor phase change in the NP, but there is significant deformation, with bent crystalline planes, and many atoms that retain sp3 coordination, but are no longer recognized as having diamond structure by different structure-identification methods. Machine-learning is used to improve diamond-structure identification. The NP deforms laterally, and volumetric strain is ~0.1 when the uniaxial strain is ~0.5. Poisson's ratio increases with strain, and the elastic limit is reached at 0.2–0.3 strain, at a contact pressure of ~150 GPa. For NPs above 5 nm, dislocations appear and are mostly (1/2) {111} full dislocations, with a few partial dislocations for larger nanoparticles, without twinning. These results agree with the recent observation of plastic deformation in diamond nanopillars. Small NP display elastic modulus, yield stress and hardness increasing with NP size, but NPs with diameter larger than 25 nm display an approximately constant dislocation and dislocation junction density, which leads to a plateau in the hardness versus NP size, at ~150 GPa, close to bulk diamond. Diamond nanoparticles could provide high strength thin coatings, lighter than full-density nanotwinned diamond but with nearly the same strength.
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•Indented diamond nanoparticles (NP) show large elastic limits at strains of 0.2‐0.3.•Structure-identification methods including machine-learning discard phase changes.•Dislocations are mostly (1/2)<1 10>{111} full dislocations, screw character.•Elastic modulus and yield strength increase with NP size, then reach a plateau.•NP hardness is ~150 GPa, comparable to bulk diamond.
In this study, the concentration of six metal(loid)s was examined in the fish
Oreochromis aureus
collected from El Comedero dam during a massive mortality event induced by a mine tailing spill. A ...major spill (~ 300,000 m
3
) of waste was released into the San Lorenzo River System following a rupture in the tailing dam of a mining plant in NW Mexico; consequently, the discharged material flowed into El Comedero dam. The accumulation of metal(oid)s in the tissues of
O. aureus
showed higher levels in the liver than in the guts and muscle. Concentrations in the liver were high (As, 1.1–1063; Cd, 8.9–392; Cu, 372–59,129; Hg, 0.46–19.79; Se, 8.7–748; and Zn, 116–820 μg g
−1
), revealing that these fish were exposed to high concentrations of these elements. The mortality of fish could have resulted from the combined effect of the six analyzed metal(loid)s, as well as other residues present in mine tailings.
The failure of a tailings dam occurred in January 2013 at the Santa María de Otáez mining region (Mexico) released a spill (~ 300,000 m
3
) on Los Remedios River, which was transported through the ...San Lorenzo River, and finally to El Comedero (EC) dam. The concentrations of metal(loid)s in the muscle, liver, gills, and guts of three fish species (
Cyprinus carpio
,
Oreochromis aureus
,
Micropterus salmoides
) collected from EC dam were examined twenty months later to assess the performance of the cleaning operations. The bioaccumulation patterns of the metal(loid)s in the tissues were different in the three fish species. Tilapia had the highest Cd (11.23 ± 8.53 µg g
−1
) and Cu (871 ± 1261 µg g
−1
) concentrations in the liver, as well as As concentration (83.6 ± 61.7 µg g
−1
) in the gut, while the highest Zn concentration (745 ± 356 µg g
−1
) was measured in the gills of the carp. Such variability can be caused by the variant bioavailability of the metal(loid)s and by the feeding habits of each species; and also by the fact that some metals are essential and better regulated by organisms than other non-essential. Compared to a study of tilapia carried out 90 days after mine spill, a decrease was evident in the liver for As, Cd, Cu, and Zn by 129, 5, 10, and 1.7 times, respectively. This revealed that cleaning operations were more efficient for As. The target hazard quotient and the hazard index were < 1, which indicates there will be no risk of consuming muscle in moderated rations of the three fish species.
In this article, a novel approach of a robust flight observer for a disturbance quadrotor transporting a payload in the presence of multiple time-varying delays is proposed. The developed algorithm ...is not only pertinent to a vehicle output signal with multiple small time-varying delays but also to long time-varying delays that are common for a quadrotor transporting a hanging load because a cascade structure is also employed to achieve outstanding performance, and the delay can be removed. The multiple time-varying delays and disturbances are compensated in the system with the proposed observer. The stability of the proposed methodology is proved using the Lyapunov-Krasovskii functional associated with an
$ \mathcal {H}_\infty $
H
∞
criterion. Numerical simulations are shown to assess and validate the observer's performance and robustness under multiple time-varying delays and disturbances.
This paper presents a methodology to solve the problem of robustification of Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC) scheme for the case of under-actuated systems ...with inertia matrix dependent of the unactuated coordinates. Specifically, we analyze the robustness of the IDA-PBC strategy with respect to constant external disturbances. This algorithm requires adding an integral action with a particular change of coordinates in an outer-loop to the IDA-PBC strategy to reject constant external disturbances. The asymptotic stability of the proposed controller despite constant external disturbances is proved using the closed-loop Hamiltonian as a Lyapunov candidate function and LaSalle’s invariance principle. Finally, as a proof of concept, we have applied the proposed robust IDA-PBC strategy to an Unmanned Aerial vehicle that transports a payload suspended by a cable, which is a class of underactuated system with inertia matrix dependent of the unactuated coordinate. Satisfactory results in numerical experiments demonstrate the applicability of the method.
Ruta chalepensis L. (Rutaceae) is used in traditional medicine to treat a wide variety of disorders such as rheumatism, fever, mental disorders, dropsy, neuralgia, menstrual problems, anxiety, and ...epilepsy.
To evaluate and compare the anticonvulsant properties of an aqueous extract and ethyl acetate (AcOEt) fraction of R. chalepensis on pentylenetetrazole (PTZ)-induced seizures and maximal electroshock (MES) test in mice, by analyzing behavior and electroencephalogram (EEG), as well as GABAA receptors involvement.
The effect of an acute administration of different dosage of the aqueous extract (300 or 500 mg/kg) or AcOEt fraction (100, 300, 500 or 1000 mg/kg) of R. chalepensis was explored on two different models of acute seizure induction in mice, the PTZ and maximal electroshock (MES) tests. Behavioral and electrographic effects were quantified. Additionally, the possible involvement of the GABAA receptors was explored in the presence of picrotoxin (a non-competitive antagonist of the GABAA receptor).
AcOEt fraction of R. chalepensis was more efficient than aqueous extract to reduce the incidence of tonic-clonic seizures and mortality in a significant and dose-dependent manner in both the PTZ and MES tests. This anticonvulsant effect was not abolished in the presence of picrotoxin. The EEG spectral power analysis revealed that aqueous extract decreased alpha and beta power, while AcOEt fraction decreased alpha and gamma power confirming previous findings of its depressant effect in the central nervous system. It is important to mention that the highest dosage of the AcOEt (1000 mg/kg) produced a severe suppression or isoelectric EEG activity (EEG flattening), recognized as a comatose state, suggesting a neurotoxic effect at this dosage.
Our data reinforce that depressant and anticonvulsant effects of R. chalepensis depend in part on the presence of constituents from medium polarity. We also found that anticonvulsant effect is not mediated by GABAA receptors. In addition, cautious is emphasized when high doses of this natural product are used in traditional medicine since it might produce neurotoxic effects.
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Obesity and undernutrition co-exist in many regions of Mexico. However, accurate assessments are difficult because epidemiological data on body composition are not available. The aim of this study ...was to facilitate assessments of body composition in Mexican school children of different geographical regions and ethnicity by developing equations for bioelectrical impedance and anthropometry based on deuterium oxide dilution.
We evaluated 336 subjects (143 belonged to six major indigenous groups) from Northern, Central and Southern Mexico. We measured height (Ht), weight (Wt), tricipital skinfold (Tricp-SKF) and resistance (R) based on a bioimpedance analysis (BIA). Fat-free mass (FFM) and fat mass (FM) were estimated from measurements of total body water with the deuterium dilution technique.
The final BIA equation was FFM (kg)=0.661 × Ht²/R+0.200 × Wt-0.320. The R² was 0.96; the square root of the mean square error (SRMSE) was 1.39 kg. The final anthropometric equation was FM (kg)=-1.067 × sex+0.458 × Tricp-SKF+0.263 × Wt-5.407. The R² was 0.91; SRMSE was 1.60 kg. The BIA equation had a bias of 0.095 kg and precision of 1.43 kg. The anthropometric equation had a bias of 0.047 kg and precision of 1.58 kg.
We validated two equations for evaluating body composition in Mexican indigenous and non-indigenous children and youth from three main regions of the country. These equations provided reliable estimates and will promote a better understanding of both obesity and undernutrition.
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