Effect of Bath Depth and Nozzle Geometry on Spout Height in Submerged Gas Injection at Bottom

Metallurgical and Materials Transactions B - Spout height is a widely used parameter to quantitatively analyze the performance of the submerged gas injection in industrial applications. However,...     

Enhancing Post-Stroke Rehabilitation and Preventing Exo-Focal Dopaminergic Degeneration in Rats—A Role for Substance P

Dopaminergic signaling is a prerequisite for motor learning. Delayed degeneration of dopaminergic neurons after stroke is linked to motor learning deficits impairing motor rehabilitation. This study investigates safety and efficacy of substance P (SP) treatment on post-stroke rehabilitation, as this neuropeptide combines neuroprotective and plasticity-promoting properties. Male Sprague Dawley rats received a photothrombotic stroke within the primary motor cortex (M1) after which a previously acquired skilled reaching task was rehabilitated. Rats were treated with intraperitoneal saline (control group, n = 7) or SP-injections (250 µg/kg) 30 min before (SP-pre; n = 7) or 16 h (SP-post; n = 6) after rehabilitation training. Dopaminergic neurodegeneration, microglial activation and substance P-immunoreactivity (IR) were analyzed immunohistochemically. Systemic SP significantly facilitated motor rehabilitation. This effect was more pronounced in SP-pre compared to SP-post animals. SP prevented dopaminergic cell loss after stroke, particularly in the SP-pre condition. Despite its proinflammatory propensity, SP administration did not increase stroke volumes, post-stroke deficits or activation of microglia in the midbrain. Finally, SP administration prevented ipsilesional hypertrophy of striatal SPergic innervation, particularly in the SP-post condition. Mechanistically, SP-pre likely involved plasticity-promoting effects in the early phase of rehabilitation, whereas preservation of dopaminergic signaling may have ameliorated rehabilitative success in both SP groups during later stages of training. Our results demonstrate the facilitating effect of SP treatment on motor rehabilitation after stroke, especially if administered prior to training. SP furthermore prevented delayed dopaminergic degeneration and preserved physiological endogenous SPergic innervation.     

Analysis of microRNAs in Exosomes of Breast Cancer Patients in Search of Molecular Prognostic Factors in Brain Metastases

Brain metastases are the most severe tumorous spread during breast cancer disease. They are associated with a limited quality of life and a very poor overall survival. A subtype of extracellular vesicles, exosomes, are sequestered by all kinds of cells, including tumor cells, and play a role in cell-cell communication. Exosomes contain, among others, microRNAs (miRs). Exosomes can be taken up by other cells in the body, and their active molecules can affect the cellular process in target cells. Tumor-secreted exosomes can affect the integrity of the blood-brain barrier (BBB) and have an impact on brain metastases forming. Serum samples from healthy donors, breast cancer patients with primary tumors, or with brain, bone, or visceral metastases were used to isolate exosomes and exosomal miRs. Exosomes expressed exosomal markers CD63 and CD9, and their amount did not vary significantly between groups, as shown by Western blot and ELISA. The selected 48 miRs were detected using real-time PCR. Area under the receiver-operating characteristic curve (AUC) was used to evaluate the diagnostic accuracy. We identified two miRs with the potential to serve as prognostic markers for brain metastases. Hsa-miR-576-3p was significantly upregulated, and hsa-miR-130a-3p was significantly downregulated in exosomes from breast cancer patients with cerebral metastases with AUC: 0.705 and 0.699, respectively. Furthermore, correlation of miR levels with tumor markers revealed that hsa-miR-340-5p levels were significantly correlated with the percentage of Ki67-positive tumor cells, while hsa-miR-342-3p levels were inversely correlated with tumor staging. Analysis of the expression levels of miRs in serum exosomes from breast cancer patients has the potential to identify new, non-invasive, blood-borne prognostic molecular markers to predict the potential for brain metastasis in breast cancer. Additional functional analyzes and careful validation of the identified markers are required before their potential future diagnostic use.     

Indentation Damage and Residual Stress Field in Alumina-Y2O3-Stabilized Zirconia Composites

Fracture features, residual stresses, and zirconia transformation are studied in indentation strength specimens of alumina-Y₂O₃-stabilized zirconia (3% mol of Y₂O₃, 3YTZP) ceramics in order to analyze the extension of the indentation damage in the bulk of the specimens. Two compositions, 5 vol% 3YTZP (A5) and 40 vol% 3YTZP (A40), have been prepared by stacking tape-casted tapes and sintering. After indentation with loads ranging from 50 to 300 N, samples were fractured in four-point bending and the fracture surfaces were characterized by scanning electron microscopy. Raman and piezospectroscopic techniques were used to determine the monoclinic zirconia fraction and the residual stresses through the fracture surfaces. In the A5 composition, the indentation damage morphology was clearly half-penny, whereas the A40 composition presented Palmqvist crack formation. Zirconia transformation was only observed in the plastically deformed zones underneath the imprints whereas there were significant residual compressive stresses outside the plastic zones due to the indentation damage. The intensity of this residual compressive field was dependent on the level of zirconia transformation due to indentation damage because zirconia transformation induced tensile stress fields superimposed on the compressive stresses.     

Sucrose hydrolysis by gelatin-immobilized inulinase from Kluyveromyces marxianus var. bulgaricus

The crude cell-free medium from a culture of Kluyveromyces marxianus var. bulgaricus was immobilized in a gelatin-water support, with an immobilization yield of 82.60% for inulinase activity. The optimum pH for both free and immobilized inulinase was the same (3.5) and the optimum temperatures were 55 °C for the free and 60 °C for the immobilized enzyme. The Arrhenius plots were linear and activation energies were 56.20 (free enzyme) and 20.27 kJ/mol K (immobilized enzyme). The kinetic parameters were calculated by Lineweaver–Burk plots and the V_max and K_m were 37.60 IU/mg protein and 61.83 mM for the free inulinase and 31.45 IU/mg protein and 149.28 mM for the immobilized enzyme, respectively. The operational stability of the immobilized inulinase was studied in a continuous fixed-bed column reactor for 33 days, at the end of which the sucrose conversion was 58.12%.     

Passive Treatment of Circumneutral Mine Drainage from the St. Louis Mine Tunnel,Rico, CO: Part 1—Case Study: Characteristics of the Mine Drainage

This publication is a case study of the seasonal variability of mine water drainage from the Saint Louis Tunnel (SLT) at the inactive Rico-Argentine mine site located in southwestern Colorado. It is an introductory paper for the two passive water treatment system technology evaluations contained in this issue. Mine water chemistry changes from baseflow to a snowmelt runoff event (SMRE) where snowmelt runoff follows preferential migration pathways to flush acidic weathering products from the upper mine workings to the SLT. Baseflow mine drainage is characterized as circumneutral, with Zn, Cd, Mn, and Ni concentrations primarily in the dissolved form. Dissolved Zn, Mn, Fe, and potentially Cd illustrate equilibrium with carbonate minerals. Total concentrations of Fe, Cu, Pb, and As are primarily in the suspended form and suggest sorption to Fe oxides. Mine water chemistry during the SMRE reflects mixing of circumneutral baseflow waters with more acidic waters flushing the upper mine workings. Geothermal activity provides for a consistently warm mine water discharge from the SLT. The two seasons that provide the most challenge to passive water treatment of SLT mine drainage are the SMRE period and the low flow stage of the Dolores River. Mine water flow and chemistry during SMRE are highly correlated with Dolores River flow and this site conceptual model was and will be used to assist in pilot project evaluation, water treatment system design, monitoring system design, a seasonal compliance approach, and water management.

     

Optimal experimental conditions for hydrogen production using low voltage electrooxidation of organic wastewater feedstock

The dependence of electrooxidation on experimental conditions of organic molecules was investigated to optimize the production of hydrogen from potential wastewater sources using low voltage sources (∼1 V dc). Electrooxidation on platinum, gold, and stainless steel anodes with hydrogen production on the cathode was investigated using several different organic reductants, including: methanol, ethanol, glycerol, isopropanol, propanal, glycerol, glucose, sucrose, citric acid, and propionic acid. The electrolyte pH was varied from 2 to 12 in a 1 M Na₂SO₄ supporting solution. At 1 V, glycerol, citric acid, ethanol and methanol were found to yield the highest currents at low pH values (pH 2 and 7) on platinum electrode, glucose on gold electrode at pH 12 in 1 M Na₂SO₄ solution produced the highest total current density at 1 V with measured Faradaic efficiency for 1 M glucose of 70%. The hydrogen energy production efficiency was 86%. Practical limitations of glucose oxidation at optimum experimental conditions are discussed.     

Detection and analysis of triterpenic compounds in apple extracts

A new technique for the rapid detection and analysis of triterpenic compounds in apple extracts using HPLC was developed and validated. The main advantage of this technique is the short duration of the analysis – this makes this technique superior to others currently applied for the routine HPLC analysis of triterpenic compounds. The developed, optimized, and validated technique was used for the evaluation of triterpenic compounds in samples of different cultivars of apples, their peels, and flesh. In total, four triterpenic compounds were isolated and identified. Ursolic acid was the dominant compound in all the tested apple samples. The highest amounts of triterpenic compounds were detected in the peels of the ‘Lodel’ apple cultivar, and thus apples of this cultivar may be potentially useful for the isolation of individual compounds and the production of functional food and dietary supplements.     

Curing behavior of a UV-curable inkjet ink: Distinction between surface-cure and deep-cure performance

Safety requirements and the need of low-migration UV inks have received increasing attention in the packaging industry. Crucial for the development and design of low-migration UV inkjet inks for migration-sensitive applications is the polymerization degree. In this study, curing-behavior of a black, high purity packaging ink (HPP-ink) was monitored using ATR-FTIR spectroscopy. UV irradiation of HPP-ink led to changes in specific absorption bands of the FTIR spectra due to crosslinking reaction of double bonds. Changes in absorptions bands at 1,408 and 1,321 cm⁻¹ permitted the determination of CC conversion of acrylic and vinyl double bond, independently of one another. In addition, a method was developed which allows the investigation of surface-cure and deep-cure behavior, separately.     

Predicting the damage development in epoxy resins using an anisotropic damage model

For fiber-reinforced plastics, the strain-rate dependent response is governed by the matrix behavior. In this work, the Goldberg model is considered for the epoxy matrix constitutive material model. Moreover, the strain-rate dependency is achieved by direct influence on the elastic modulus, the inelastic strain, and the material strain to failure. In addition, an anisotropic damage response is implemented and extended through a strain-rate dependent definition. Since the constitutive model relies on nonphysical parameters, a parameter study is further performed. Additional numerical investigations using a micro-mechanical model are performed. Tension and shear loading conditions are evaluated and the influence of different strain rates is explored. Furthermore, the implemented anisotropic damage model is compared and discussed against an isotropic damage model.