We consider a general multi-agent convex optimization problem where the agents are to collectively minimize a global objective function subject to a global inequality constraint, a global equality ...constraint, and a global constraint set. The objective function is defined by a sum of local objective functions, while the global constraint set is produced by the intersection of local constraint sets. In particular, we study two cases: one where the equality constraint is absent, and the other where the local constraint sets are identical. We devise two distributed primal-dual subgradient algorithms based on the characterization of the primal-dual optimal solutions as the saddle points of the Lagrangian and penalty functions. These algorithms can be implemented over networks with dynamically changing topologies but satisfying a standard connectivity property, and allow the agents to asymptotically agree on optimal solutions and optimal values of the optimization problem under the Slater's condition.
This literature research, although not exhaustive, gives perspective to solar-driven photocatalysis, such as solar photo-Fenton and TiO2 solar photocatalysis, reported in the literature for the ...degradation of aqueous organic pollutants. Parameters that influence the degradation and mineralization of organics like catalyst preparation, type and load of catalyst, catalyst phase, pH, applied potential, and type of organic pollutant are addressed. Such parameters may also affect the photoactivity of the catalysts used in the studied solar processes. Solar irradiation is a renewable, abundant, and pollution-free energy source for low-cost commercial applications. Therefore, these solar processes represent an environmentally friendly alternative mainly because the use of electricity can be decreased/avoided.
Chagas disease, caused by the protozoan parasite
, affects millions of people in the Americas and across the world, leading to considerable morbidity and mortality. Current treatment options, ...benznidazole (BNZ) and nifurtimox, offer limited efficacy and often lead to adverse side effects because of long treatment durations. Better treatment options are therefore urgently required. Here, we describe a pyrrolopyrimidine series, identified through phenotypic screening, that offers an opportunity to improve on current treatments. In vitro cell-based washout assays demonstrate that compounds in the series are incapable of killing all parasites; however, combining these pyrrolopyrimidines with a subefficacious dose of BNZ can clear all parasites in vitro after 5 days. These findings were replicated in a clinically predictive in vivo model of chronic Chagas disease, where 5 days of treatment with the combination was sufficient to prevent parasite relapse. Comprehensive mechanism of action studies, supported by ligand-structure modeling, show that compounds from this pyrrolopyrimidine series inhibit the Q
active site of
cytochrome b, part of the cytochrome bc
complex of the electron transport chain. Knowledge of the molecular target enabled a cascade of assays to be assembled to evaluate selectivity over the human cytochrome b homolog. As a result, a highly selective and efficacious lead compound was identified. The combination of our lead compound with BNZ rapidly clears
parasites, both in vitro and in vivo, and shows great potential to overcome key issues associated with currently available treatments.
A semiempirical approach involving quantum chemical calculations was used to rationalize the mimosa tannin inhibitory action. The molecular spatial structure, atomic charges, dipole moment, HOMO–LUMO ...energy gap and HOMO density of four types of flavanoid units that constitute mimosa tannin, have been theoretically investigated using HyperChem 5.11 computer package. Optimization of the molecular geometry yielded a non-planar structure with the electron charge density distributed non-uniformly. The HOMO–LUMO energy gap was used to determine the electron donating ability of the molecule. The highest values of the HOMO density was found in the vicinity of the functional groups indicating them as most probable adsorption centers.
A schematic representation of the different modes of adsorption of mimosa tannin is presented. The projected molecular area for a particular molecular orientation was compared to the area occupied by
X water molecules displaced from the surface in the process of adsorption.
X was determined from the Flory–Huggins, Dhar–Flory–Huggins and Bockris–Swinkels substitutional adsorption isotherms applied to the data obtained from the gravimetric experiments performed on low carbon steel specimen in 0.1
M H
2SO
4 solution at 30±1
°C. The value of
X≈4, and most probable vertical orientation tannin molecules in the adsorbed state were deduced from these considerations.
Leptospirosis, a spirochaetal zoonosis, occurs in diverse epidemiological settings and affects vulnerable populations, such as rural subsistence farmers and urban slum dwellers. Although ...leptospirosis is a life-threatening disease and recognized as an important cause of pulmonary haemorrhage syndrome, the lack of global estimates for morbidity and mortality has contributed to its neglected disease status.
We conducted a systematic review of published morbidity and mortality studies and databases to extract information on disease incidence and case fatality ratios. Linear regression and Monte Carlo modelling were used to obtain age and gender-adjusted estimates of disease morbidity for countries and Global Burden of Disease (GBD) and WHO regions. We estimated mortality using models that incorporated age and gender-adjusted disease morbidity and case fatality ratios. The review identified 80 studies on disease incidence from 34 countries that met quality criteria. In certain regions, such as Africa, few quality assured studies were identified. The regression model, which incorporated country-specific variables of population structure, life expectancy at birth, distance from the equator, tropical island, and urbanization, accounted for a significant proportion (R(2) = 0.60) of the variation in observed disease incidence. We estimate that there were annually 1.03 million cases (95% CI 434,000-1,750,000) and 58,900 deaths (95% CI 23,800-95,900) due to leptospirosis worldwide. A large proportion of cases (48%, 95% CI 40-61%) and deaths (42%, 95% CI 34-53%) were estimated to occur in adult males with age of 20-49 years. Highest estimates of disease morbidity and mortality were observed in GBD regions of South and Southeast Asia, Oceania, Caribbean, Andean, Central, and Tropical Latin America, and East Sub-Saharan Africa.
Leptospirosis is among the leading zoonotic causes of morbidity worldwide and accounts for numbers of deaths, which approach or exceed those for other causes of haemorrhagic fever. Highest morbidity and mortality were estimated to occur in resource-poor countries, which include regions where the burden of leptospirosis has been underappreciated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Over one hundred and fifty references, one third of which from the last three years.•Cycles are classified into categories according to common features.•Forty-two categories for stand-alone cycles ...and thirty-eight for combined layouts.•Stand-alone (simple) cycles in literature show dispersion of up to 30%.•Stand-alone (simple) cycles in literature show dispersion of up to 50%.
Power cycles running on carbon dioxide at supercritical pressure and temperature were introduced in the late ninety-sixties but, after a warm welcome to the theoretical performance announced, they were later abandoned in favour of standard combustion gas turbines. Nevertheless, the technology was brought forward about a decade ago and has since captured significant attention from the scientific and industrial community. The number of publications has risen exponentially and there are several experimental projects under development today. The performances of these cycles have been deeply analysed in literature, proving to be theoretically competitive.
This paper reviews all the works published in the topic to date. Different cycle concepts (stand-alone and in combination with other cycles using the same or different technologies), layouts, fuels, applications (power only or combined heat and power) and operating conditions are reviewed and categorised according to the configuration of the cycle. This latter feature is thought to be an interesting added value of this paper since, rather than just listing the past work in the area of sCO2 power cycles, it also organises the numerous cycles in different categories and provides a comparison of the claimed performance of each one of them.
This comparison between the performances of the various configurations is based on the values declared in the original papers and thus applies to very different boundary conditions. Obviously, this great heterogeneity of the available data (in particular the temperatures and pressures considered) makes it impossible to establish a fair comparison between the configurations reviewed. Therefore, a future study seems to be mandatory where the performances of all cycles should be compared for the same set of operating conditions.
Shortcuts to adiabaticity (STA) are fast routes to the final results of slow, adiabatic changes of the controlling parameters of a system. The shortcuts are designed by a set of analytical and ...numerical methods suitable for different systems and conditions. A motivation to apply STA methods to quantum systems is to manipulate them on timescales shorter than decoherence times. Thus shortcuts to adiabaticity have become instrumental in preparing and driving internal and motional states in atomic, molecular, and solid-state physics. Applications range from information transfer and processing based on gates or analog paradigms to interferometry and metrology. The multiplicity of STA paths for the controlling parameters may be used to enhance robustness versus noise and perturbations or to optimize relevant variables. Since adiabaticity is a widespread phenomenon, STA methods also extended beyond the quantum world to optical devices, classical mechanical systems, and statistical physics. Shortcuts to adiabaticity combine well with other concepts and techniques, in particular, with optimal control theory, and pose fundamental scientific and engineering questions such as finding speed limits, quantifying the third law, or determining process energy costs and efficiencies. Concepts, methods, and applications of shortcuts to adiabaticity are reviewed and promising prospects are outlined, as well as open questions and challenges ahead.
The objectives of this study were to determine the metals and arsenic transfer from mining ponds to agricultural and forest soils, and identify the dynamic of metal(loid)s in the soil-plant system ...for a native plant species (Ballota hirsuta) in two old mining districts: La Unión and Mazarrón (Spain). Soils and plants from mining ponds and natural and agricultural areas were collected and analyzed for soil properties, and chemical partitioning of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn and As. Results showed that mine, forest and agricultural soils were contaminated by As, Cd, Cu, Pb, and Zn. Chemical partitioning revealed higher mobility of metals in mining ponds than natural and agricultural soils except for Fe and As which were mostly bound to soil matrix due to the mineralogical compositions of soils. The accumulation of metal(loid)s in B. hirsuta in La Unión decreased as Fe > As > Cr > Ni > Cu > Zn > Cd > Mn > Co > Pb while in Mazarrón was As > Fe > Cr > Pb > Cu > Ni > Co > Mn > Zn > Cd, showing that B. hirsuta has high ability to bio-accumulate Fe, As, Cr, Cu and Ni; and Pb (in Mazarrón), transferring a significant concentration of theses metal(loid)s, except Pb, to edible parts without exceeding the toxicity limits for animals. Therefore, B. hirsuta could be useful as phytoextractor species for Cr, Cu, As and Ni, while it can be used as phytostabilizer species for Zn, Co, Pb and Cd.
Display omitted
•Agriculture soils are enriched in As, Cd, Fe, Pb and Zn from mine wastes.•Higher metals concentration are bound to the labile fraction in mining wastes.•Cr, Ni, Fe, As and Cu were mostly bound to the soil matrix.•Ballota hirsuta accumulates Fe, Cr and As in leaves.•Ballota hirsuta could be useful in phytoremediation in semiarid climates.
Agricultural soils are enriched in metal(loid)s from mine wastes. B. hirsuta accumulates Cr, Cu, As and Ni in leaves.
Graphene quantum dots in analytical science Benítez-Martínez, S.; Valcárcel, M.
TrAC, Trends in analytical chemistry (Regular ed.),
October 2015, 2015-10-00, Letnik:
72
Journal Article
Recenzirano
Odprti dostop
•Graphene quantum dots are fluorescent nanoparticles with unique properties.•Analytical applications of graphene quantum dots.•Graphene quantum dots in development of analytical sensors and ...biosensors.•Development of analytical techniques based on graphene quantum dots.•Analytical methods needed to determine graphene quantum dots.
Graphene quantum dots (GQDs) are small fluorescent nanoparticles with unique properties that make them attractive tools for research in various fields. We review their state of the art in analytical chemistry and summarize their analytical applications. Also, we deal with GQDs as target analytes, a scarcely explored aspect in analytical nanoscience and nanotechnology, and suggest potential future directions for GQD-based analytical research.
The turbine blade test parts were manufactured by the selective laser melting (SLM) process using a nickel-based pre-alloyed Inconel (IN) 718 powder. Various mechanical post-processing techniques, ...such as barrel finishing (BF), shot peening (SP), ultrasonic shot peening (USP), and ultrasonic impact treatment (UIT), were applied to improve the surface layer properties of the SLM-built specimens. Effects of mechanical surface treatments on surface topography, porosity, hardness, and residual stress were studied. In comparison with the SLM-built state the surface roughness (Sa = 5.27 μm) of the post-processed specimens were respectively decreased by 20.6%, 26.2%, and 57.4% after the BF, USP, and UIT processes except for the SP-treated ones. The Sz parameter was reduced in all treated SLM-built specimens except for the SP-treated ones. The surface microhardness of the SLM-built specimen (~390 HV0.025) was increased after the BF (by 14.2%), USP (by 23.8%), UIT (by 50%), and SP (by 66.5%) processes. The deepest hardened layers were formed after the UIT and SP processes. Residual porosity of the SLM-built specimen was decreased by 23.1%, 40.6%, 55%, and 84% after the BF, SP, USP and UIT processes, respectively. The UIT process formed a densified subsurface layer of significantly reduced porosity (0.118%). All mechanical surface treatments successfully transformed the tensile residual stresses generated in SLM-built specimen into the compressive residual stresses (−201.4...510.7 MPa). The thickness of hardened, densified and compressed near-surface layers ranges from ~80 μm after BF to ~140 μm after USP, and ~180 μm after SP and UIT processes, which correlates to the accumulated energy and deformation extent of the treated surface. The effect of the accumulated energy on the outcomes of the applied surface treatments is also addressed.
•The turbine blade test IN 718 parts were manufactured by selective laser melting (SLM)•Mechanical post-processing techniques were applied to improve the surface layer properties•Barrel finishing (BF), shot peening (SP), ultrasonic shot peening (USP), and ultrasonic impact treatment (UIT) were used•Surface texture, roughness, hardness, porosity, and residual stress were studied
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