Voltage cycling process for the electroconversion of biomass-derived polyols

Electrification of chemical reactions is crucial to fundamentally transform our society that is still heavily dependent on fossil resources and unsustainable practices. In addition, electrochemistry-based approaches offer a unique way of catalyzing reactions by the fast and continuous alteration of applied potentials, unlike traditional thermal processes. Here, we show how the continuous cyclic application of electrode potential allows Pt nanoparticles to electrooxidize biomass-derived polyols with turnover frequency improved by orders of magnitude compared with the usual rates at fixed potential conditions. Moreover, secondary alcohol oxidation is enhanced, with a ketoses-to-aldoses ratio increased up to sixfold. The idea has been translated into the construction of a symmetric single-compartment system in a two-electrode configuration. Its operation via voltage cycling demonstrates high-rate sorbitol electrolysis with the formation of H2 as a desired coproduct at operating voltages below 1.4 V. The devised method presents a potential approach to using renewable electricity to drive chemical processes.

Development of a Compartmental Pharmacokinetic Model for Molecular Radiotherapy with 131I-CLR1404

Pharmacokinetic modeling of the radiopharmaceuticals used in molecular radiotherapy is an important step towards accurate radiation dosimetry of such therapies. In this paper, we present a pharmacokinetic model for CLR1404, a phospholipid ether analog that, labeled with 124I/131I, has emerged as a promising theranostic agent. We follow a systematic approach for the model construction based on a decoupling process applied to previously published experimental data, and using the goodness-of-fit, Sobol’s sensitivity analysis, and the Akaike Information Criterion to construct the optimal form of the model, investigate potential simplifications, and study factor prioritization. This methodology was applied to previously published experimental human time-activity curves for 9 organs. The resulting model consists of 17 compartments involved in the CLR1404 metabolism. Activity dynamics in most tissues are well described by a blood contribution plus a two-compartment system, describing fast and slow uptakes. The model can fit both clinical and pre-clinical kinetic data of 124I/131I. In addition, we have investigated how simple fits (exponential and biexponential) differ from the complete model. Such fits, despite providing a less accurate description of time-activity curves, may be a viable alternative when limited data is available in a practical case.

Mathematical modeling of the effects of Wnt-10b on bone metabolism

Bone health is determined by many factors including bone metabolism or remodeling. Wnt-10b has been shown to alter osteoblastogenesis through pre-osteoblast proliferation and differentiation as well as the osteoblast apoptosis rate, which collectively lead to the increase of bone density. To model this change, we adapted a previously published model of bone remodeling. The resulting model is a single compartment system that includes ordinary differential equations for active osteoclasts, pre-osteoblasts, osteoblasts, and osteocytes and a differential equation that tracks the amount of bone present at the remodeling site. Our alterations to the original model consist of extending it past a single remodeling cycle and implementing a direct relationship to Wnt-10b. Four new parameters were estimated and validated using normalized data from mice. The model connects Wnt-10b to bone metabolism and predicts the change in bone volume caused by a change in Wnt-10b. We find that this model predicts the expected increase in pre-osteoblasts and osteoblasts while also pointing to a decrease in osteoclasts when Wnt-10b is increased.

The role of endoplasmic reticulum in in vivo cancer FDG kinetics

A recent result obtained by means of an in vitro experiment with cancer cultured cells has configured the endoplasmic reticulum as the preferential site for the accumulation of 2-deoxy-2-[18F]fluoro-D-glucose (FDG). Such a result is coherent with cell biochemistry and is made more significant by the fact that the reticular accumulation rate of FDG is dependent upon extracellular glucose availability. The objective of the present paper is to confirm in vivo the result obtained in vitro concerning the crucial role played by the endoplasmic reticulum in FDG cancer metabolism. This study utilizes data acquired by means of a Positron Emission Tomography scanner for small animals in the case of CT26 models of cancer tissues. The recorded concentration images are interpreted within the framework of a three-compartment model for FDG kinetics, which explicitly assumes that the endoplasmic reticulum is the dephosphorylation site for FDG in cancer cells. The numerical reduction of the compartmental model is performed by means of a regularized Gauss-Newton algorithm for numerical optimization. This analysis shows that the proposed three-compartment model equals the performance of a standard Sokoloff’s two-compartment system in fitting the data. However, it provides estimates of some of the parameters, such as the phosphorylation rate of FDG, more consistent with prior biochemical information. These results are made more solid from a computational viewpoint by proving the identifiability and by performing a sensitivity analysis of the proposed compartment model.

Attraction and penetration of Musa by the burrowing nematode, Radopholus similis, in an autotrophic bipartite culture system

Summary Our objective was to discover the stages (pre- or post-infection) in which the resistance to burrowing nematode (Radopholus similis) occurs in two resistant banana (Musa spp.) cultivars. An autotrophic in vitro culture system was used to compare R. similis migration towards, and penetration into, the banana roots. A new two-compartment autotrophic in vitro model system was developed using agar-based medium to examine the migration of R. similis to either the susceptible ‘Grande Naine’ or the resistant ‘Yangambi km5’ (‘Ykm5’), when both the Musa genotypes were present at equal distance. The autotrophic in vitro model system was advantageous, because it supported continuous root growth due to the actively photosynthesising shoots growing in the open air, while the in vitro root conditions make it possible to observe and assess the nematode chemotaxis in the transparent medium. Significantly fewer nematodes migrated towards the resistant ‘Ykm5’ plants when compared to both the susceptible ‘Grande Naine’, and another resistant cultivar, ‘Saba’, at 1 h after infection. This signals a possibility of a lower concentration or different composition of nematode attractants in ‘Ykm5’ root exudates. No significant differences were observed in the percentage of R. similis that migrated towards the roots of the susceptible and resistant banana plants at 3, 4 and 6 h after inoculation. No significant differences were observed in the percentages of female penetration in the resistant and susceptible plant roots at 1 and 2 days after inoculation. The results of the two-compartment system confirmed that when a choice is given to migrate towards the resistant and susceptible genotypes, no differences were observed in the percentage of female migration towards both the genotypes.

Creating an Artificial 3-Dimensional Ovarian Follicle Culture System Using a Microfluidic System

We hypothesized that the creation of a 3-dimensional ovarian follicle, with embedded granulosa and theca cells, would better mimic the environment necessary to support early oocytes, both structurally and hormonally. Using a microfluidic system with controlled flow rates, 3-dimensional two-layer (core and shell) capsules were created. The core consists of murine granulosa cells in 0.8 mg/mL collagen + 0.05% alginate, while the shell is composed of murine theca cells suspended in 2% alginate. Somatic cell viability tests and hormonal assessments (estradiol, progesterone, and androstenedione) were performed on days 1, 6, 13, 20, and 27. Confocal microscopy confirmed appropriate compartmentalization of fluorescently-labeled murine granulosa cells to the inner capsule and theca cells to the outer shell. Greater than 78% of cells present in capsules were alive up to 27 days after collection. Artificially constructed ovarian follicles exhibited intact endocrine function as evidenced by the production of estradiol, progesterone, and androstenedione. Oocytes from primary and early secondary follicles were successfully encapsulated, which maintained size and cellular compartmentalization. This novel microfluidic system successfully encapsulated oocytes from primary and secondary follicles, recapitulating the two-compartment system necessary for the development of the mammalian oocyte. Importantly, this microfluidic system can be easily adapted for sterile, high throughput applications.

Effect of a Freezing-thawing Cycle on Overall and Inter-variability of Runoff and Soil Loss Components for a Loess Soil

Background: Because control of runoff generation as well as soil loss is influenced by freezing-thawing, proper knowledge and insight into the freezing-thawing process in combination with other hydrological processes is essential for executives and planners. However, such dynamic phenomenon and corresponding consequences have not been studied adequately. The present study was therefore planned to comparatively analyze the effects of a freezing-thawing cycle on hydrologic behaviors of loess soil from northeast of Iran. Towards that, the small-size (0.5×0.50×0.30 m) erosion plots were subjected to a freezing-thawing cycle in accordance with governing conditions on the region of the origin soil. The plots were subjected to a freezing-thawing treatment through inducing cold air until temperature declined to below -20 °C and lasted for three days using a large cooling compartment system, and then were kept in the laboratory with ambient temperature of above 10 °C for two days. The treated plots as well as untreated (control) plots were then exposed to a simulated rainfall with an intensity of 72 mm h-1 and 0.5 h duration while they were placed on a slope of 20%. Results: The results indicated that the hybrid processes of freezing-thawing, and splash and interrill erosions significantly affected runoff generation and soil loss at small plots. So that the time to runoff reduced by 1.65 times in the freezing-thawing treatment compared to that reported for the control treatment. The runoff volume and soil loss also increased at tune of 1.38 and 2.90 times in treated plots in comparison with those measured for the untreated plots. Laboratorial results indicated significant differences (p< 0.006) between runoff and soil loss behaviors in plots subjected to a freezing-thawing cycle and those of control condition. Conclusion: The performance of ice lenses and freezing fronts and creating near-saturation moisture after completing the cycle were evaluated as the most important factors affecting the different soil behaviors under frozen-thawed cycle.

Ensuring the eco safety of mixing departments steel melting shops

Introduction. Mixer branches of metallurgical enterprises are an intermediate link between blast furnace and steelmaking workshops. They are equipped with mixers – footer containers for storing cast iron melt. In Ukraine, mixers with a capacity of 1300 or 2500 tons are used. Technological operations are accompanied by emissions of finely dispersed brown smoke and large-dispersed graphite dust into the atmosphere. Problem. Mixer compartments of Ukrainian factories are equipped with aspiration systems that dimity emissions from cast iron pouring and draining units with the help of fume tubes, then emissions pass the dust collector and discharge into the atmosphere through a chimney. The main impact of mixer compartments on the environment is: disorganized emission through an aerodynamic dust lamp, which is not allotted by the aspiration system; organized emission through a smoke pipe of dust not caught by a dust collector; solid waste from gas cleaning and dust hoppers settling on the floor and structures of the mixer compartment from the disorganized ejection that did not come out through the lantern. The main problems are insufficient aspiration (disorganized emission) and low emission purification efficiency (emission through the chimney). A separate problem is the disposal of caught dust. The degree of aspiration in the factories of Ukraine is about 0.7 for the filling unit in the mixer and 0.8 for the drain unit from the mixer at the power of the aspiration system 150-250 thousand tons. This does not meet modern requirements. Results. Cyclones are used as a dust collector in most factories, which completely capture graphite, but are not effective enough for brown smoke. Therefore, it is proposed to use sleeve filters or electro filters. It is also possible to introduce the suppression of brown smoke with nitrogen. The use of nitrogen is possible in accordance with cyclones (for existing systems) or compatible with filters (during reconstruction or new construction). The use of suppression of brown smoke with nitrogen allows to solve the problem of disposal of caught dust, because nitrogen supply leads to enrichment of dust with graphite. The content of graphite increases from 15% to more than 30%, which converts dust from care to commodity product. Keywords: mixer, cast iron pouring, cast iron drainage, dust suppression by nitrogen, aspirational mixer compartment system.

Existence of positive solutions for a fractional compartment system

In this article, we investigate the existence of positive solutions of a boundary value problem for a system of fractional differential equations. The resilience of a fractional compartment system is also studied to demonstrate the application of the result.