Determining casting defects in near-net shape casting aluminum parts by computed tomography

Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.     

Phosphatidylserine Supplementation as a Novel Strategy for Reducing Myocardial Infarct Size and Preventing Adverse Left Ventricular Remodeling

Phosphatidylserines are known to sustain skeletal muscle activity during intense activity or hypoxic conditions, as well as preserve neurocognitive function in older patients. Our previous studies pointed out a potential cardioprotective role of phosphatidylserine in heart ischemia. Therefore, we investigated the effects of phosphatidylserine oral supplementation in a mouse model of acute myocardial infarction (AMI). We found out that phosphatidylserine increases, significantly, the cardiomyocyte survival by 50% in an acute model of myocardial ischemia-reperfusion. Similar, phosphatidylserine reduced significantly the infarcted size by 30% and improved heart function by 25% in a chronic model of AMI. The main responsible mechanism seems to be up-regulation of protein kinase C epsilon (PKC-ε), the main player of cardio-protection during pre-conditioning. Interestingly, if the phosphatidylserine supplementation is started before induction of AMI, but not after, it selectively inhibits neutrophil’s activation, such as Interleukin 1 beta (IL-1β) expression, without affecting the healing and fibrosis. Thus, phosphatidylserine supplementation may represent a simple way to activate a pre-conditioning mechanism and may be a promising novel strategy to reduce infarct size following AMI and to prevent myocardial injury during myocardial infarction or cardiac surgery. Due to the minimal adverse effects, further investigation in large animals or in human are soon possible to establish the exact role of phosphatidylserine in cardiac diseases.     

Comparison and Validation of Different Magnetic Force Microscopy Calibration Schemes

The future of consumer electronics depends on the capability to reliably fabricate nanostructures with given physical properties. Therefore, techniques to characterize materials and devices with nanoscale resolution are crucial. Among these is magnetic force microscopy (MFM), which transduces the magnetic force between the sample and a magnetic oscillating probe into a phase shift, enabling the locally resolved study of magnetic field patterns down to 10 nm. Here, the progress done toward making quantitative MFM a common tool in nanocharacterization laboratories is shown. The reliability and ease of use of the calibration method based on a magnetic reference sample, with a calculable stray field, and a deconvolution algorithm is demonstrated. This is achieved by comparing two calibration approaches combined with numerical modeling as a quantitative link: measuring the probe's effect on the voltage signal when scanning above a nanosized graphene Hall sensor, and recording the MFM phase shift signal when the probe scans across magnetic fields produced by metallic microcoils. Furthermore, in the case of the deconvolution algorithm, it is shown how it can be applied using the open‐source software package Gwyddion. The estimated magnetic dipole approximation for the most common probes currently in the market is also reported.     

Lead, cadmium, and zinc concentrations in plaster and mortar from structures in Jasper and Newton Counties, Missouri (Tri-State Mining District)

The primary goal of this study was to evaluate anecdotal evidence that within Jasper and Newton Counties, Missouri, two counties within the Tri-State Mining District, granular mine tailings were commonly used in place of river sands in wall plasters and mortar. Interior wall plaster and mortar samples from structures in this mining district were analyzed for lead, cadmium, and zinc, and compared to samples from Springfield, MO (comparison site). The Jasper and Newton County samples showed elevated concentrations of the three elements, consistent with the inclusion of mine tailings, with a number of samples containing lead and cadmium at concentrations greater than EPA remediation targets for yard soil. X-ray diffraction studies showed the presence of the zinc ore minerals, sphalerite and hemimorphite, in high level samples. Thin section optical studies identified the major component of the aggregate as chert, a mineral abundant within the tailing piles. Because dust from crumbling plaster and mortar could represent an avenue for significant heavy metal exposure to building occupants, we suggest that there may be associated health consequences that should be further evaluated.     

Bioluminescence ATP monitoring as a surrogate marker for microbial load on hands and surfaces in the home

To evaluate the validity and reliability of adenosine triphosphate (ATP) monitoring as a surrogate marker for cleanliness, the kitchen table surface in 225 inner-city homes was sampled by microbiologic culture and by two types of biomass monitoring systems (HY-LiTEtrade mark 2 ATP System and HY-RiSE Colour Hygiene Test Strip, EM Science, Gibbstown, New Jersey, USA). A randomly selected hand of the homemaker (n = 225) was also cultured and sampled with the ATP monitoring system immediately after handwashing. Log microbial counts on hands ranged from 3.2 to 7.0 and from the table, 1.0 to 5.5. While the traditional ATP readings (HY-LiTE) and the color strips were significantly correlated (R = 0.18, P = 0.01), there was no significant correlation between the ATP monitor readings and the colony-forming units counts on either the hands (R = 0.03, P = 0.62) or the table (R = 0.04, P = 0.58). Such biomass measurements are not a substitute for quantitation of microbial load.     

High-voltage photography: a new method for optical detection of moisture distribution in wood and wood-based panel products

This study is based on experiments in which the distribution of moisture in freshly wood, oven-dried wood and various wood-based panel products was observed at different moisture contents. High-voltage photography was used to analyze cross sections of branches from Picea abies under different water conditions (60, 43, 19, 0%), determined gravimetrically by oven-drying at 103 °C after having taken the photographs. The voltage photographs show significant moisture differences between heartwood and sapwood which are usually not visible in trees with colourless heartwood. Moreover, moisture differences between compression wood and normal wood were clearly shown to exist. With regard to wood-based panel products moisture variations between different products as well as between the different components of one product were significantly observed by voltage photography and correlated to gravimetric measurements.     

Cathodic preconcentration of f-elements on a mercury film carbon fiber disk microelectrode

Field detection and quantification of f-elements is an important problem in radioanalytical chemistry requiring small, portable devices. Here, characterization of a 10 μm Hg film carbon fiber disk microelectrode to accumulate f-elements is described. Accumulation was performed by cathodic deposition and evaluated by anodic stripping and subsequent ICPMS analyses. La(3+) was used as the model element, and subsequent studies were conducted on a 17 element mixture (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th). In the model studies, La(3+) undergoes a sorption phenomenon, and as in other studies and confirmed by ICPMS, a monolayer of atoms on the electrode surface is formed. Dissolved O(2) was found to have no effect on the cathodic accumulation of La(3+). Consideration of electrode reaction conditions is made, and reactions are hypothesized. The limit of detection (LOD) was found to be 10(-7) M with mass detection of 10(9) atoms, approximately 5 orders of magnitude less than at conventionally sized electrodes. To solve a dilution problem in follow-on analyses, a suggestion to use microelectrode chip-based sensors was made.     

Copper‐Catalyzed Direct Arylselenation of Anilines by C?H Bond Cleavage

We describe here an efficient and regioselective synthesis of arylselanyl anilines by copper‐catalyzed direct arylselenation of arylamines. Using a catalytic amount of copper iodide in dimethyl sulfoxide at 110 °C under an air atmosphere, a range of arylselanyl anilines was obtained directly from substituted diaryl diselenides in moderate to good yields via C H bond cleavage of aryl amines.

     

Increased neopterin in patients with chronic and acute coronary syndromes

The effect of aprotinin on Schistosoma mansoni miracidial penetration process, by its direct topical application on Biomphalaria alexandrina snails, was studied The snails were exposed to S. mansoni miracidial suspension which was mixed with aprotinin at concentrations ranging from 0.02 to 20 Kallikrein inactivator units (KIU)/ml of applied solution. Results showed that aprotinin had marked inhibitory effect on miracidial penetration of the snails. The concentration that resulted in 50% inhibition of the miracidial penetration into B. alexandrina snails (LD50) was 2.4 KIU/ml while (LD96) was 20 KIU/ml of the applied solution. Thus, aprotinin may be one of the important methods in the control of schistosomiasis.