CuO Nanoparticles and Microaggregates: An Experimental and Computational Study of Structure and Electronic Properties

The link between morphology and properties is well-established in the nanoparticle literature. In this report, we show that different approaches in the synthesis of copper oxide can lead to nanoparticles (NPs) of different size and morphology. The structure and properties of the synthesized NPs are investigated with powder X-ray diffraction, scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS). Through detailed SEM analyses, we were able to correlate the synthetic pathways with the particles' shape and aggregation, pointing out that bare hydrothermal pathways yield mainly spheroidal dandelion-like aggregates, whereas, if surfactants are added, the growth of the nanostructures along a preferential direction is promoted. The effect of the morphology on the electronic properties was evaluated through DRS, which allowed us to obtain the electron bandgap in every system synthesized, and to find that the rearrangement of threaded particles into more compact structures leads to a reduction in the energy difference. The latter result was compared with Density Functional Theory (DFT) computational models of small centrosymmetric CuO clusters, cut from the tenorite crystal structure. The computed UV-Vis absorption spectra obtained from the clusters are in good agreement with experimental findings.

[Effect of application of cow manure and green manure on corn yield and soil physical-chemical properties in land restoration area]

The effects of cow manure and green manure on maize yield, soil respiration and soil physical-chemical properties in land restoration area was evaluated through field experiments. The results indicated that the maize yield and thousand-grain mass with cow manure were increased by 7.2%-29.9% and 2.5%-18.2%, respectively compared with the application of chemical fertilizer (CF), while the soil active organic carbon and organic matter contents of cow manure were 5.3%-34.6% and 8.0%-17.6% higher than that obtained in CF. The maize yield and thousand-grain mass were increased by 10.8%-15.6% and 4.5%-8.4% with application of green manure, respectively compared with CF. The content of active organic carbon in green manure was 14.1%-48.6% higher than that detected in CF. In the second year, the content of organic matter in green manure treatment was 7.2% higher than that of CF. The soil respiration rates under cow manure and green manure treatments increased by 20.0%-69.3% compared with CF. CF and green manure could improve the soil bulk density and increase the aggregate ratios of ＜0.01 mm and 0.05-1 mm fractions, respectively. On the other hand, the cow manure and green manure could decrease the soil total porosity and the capillary porosity. In conclusion, the application of cow manure and green manure in land restoration region could increase maize yield during the two consecutive seasons, which showed a positive response to improvement of soil physical-chemical properties.

Evaluation of confocal laser scanning microscopy for enumeration of virus-like particles in aquatic systems

Abundances of virus-like particles (VLPs, mostly bacteriophages) are high in aquatic environments; therefore, techniques for precise enumeration are essential in ecological monitoring. VLPs were determined after staining with SYBR Gold by conventional epifluorescence microscopy and compared to enumerations performed by confocal laser scanning microscopy (CLSM). In order to assess the potential of CLSM for viral direct counts (VDCs), we processed samples from different freshwater and marine systems. Optical sectioning by CLSM and production of an overlay picture of multiple scans enables the often uneven whole investigated filter area to be brought to the plane of focus. This allows for subsequent image analysis of digitally created high-quality images. Another advantage using the CLSM was that the short spot excitation of the stain via laser beam minimized fading of the stain. The VDC results show that there is no significant difference between the two methods. Regarding the known difficulties of viral abundance estimates on particulate material, CLSM was further applied to enumerate VLPs on a small set of marine transparent exopolymeric particles sampled from the Atlantic Ocean. Our data suggest that CLSM is a useful tool to count viruses in water samples as well as attached to certain types of aquatic aggregates.

Elevated atmospheric carbon dioxide increases soil carbon

The general lack of significant changes in mineral soil C stocks during CO₂ -enrichment experiments has cast doubt on predictions that increased soil C can partially offset rising atmospheric CO₂ concentrations. Here, we show, through meta-analysis techniques, that these experiments collectively exhibited a 5.6% increase in soil C over 2-9 years, at a median rate of 19 g C m^-2  yr^-1 . We also measured C accrual in deciduous forest and grassland soils, at rates exceeding 40 g C m^-2  yr^-1 for 5-8 years, because both systems responded to CO₂ enrichment with large increases in root production. Even though native C stocks were relatively large, over half of the accrued C at both sites was incorporated into microaggregates, which protect C and increase its longevity. Our data, in combination with the meta-analysis, demonstrate the potential for mineral soils in diverse temperate ecosystems to store additional C in response to CO₂ enrichment.

Early motor dysfunction and striosomal distribution of huntingtin microaggregates in Huntington's disease knock-in mice

Huntington's disease (HD) is characterized by a progressive loss of neurons in the striatum and cerebral cortex and is caused by a CAG repeat expansion in the gene encoding huntingtin. Mice with the mutation inserted into their own huntingtin gene (knock-in mice) are, genetically, the best models of the human disease. Here we show for the first time that knock-in mice with 94 CAG repeats develop a robust and early motor phenotype at 2 months of age, characterized by increased rearing at night. This initial increase in repetitive movements was followed by decreased locomotion at 4 and 6 months, despite a normal life span. The decrease in striatal enkephalin mRNA that is known to occur at 4 months was not present at 2 months, when increased rearing was observed. Both the hyperactive and hypoactive phases of motor dysfunction preceded the detection of nuclear microaggregates of mutated huntingtin in striatal neurons. Nuclear microaggregates, defined as small huntingtin-positive punctas detected by light microscopy, were very rare at 4 months but became widely distributed in striatal neurons at 6 months. Nuclear inclusions did not appear until 18 months. When present, nuclear microaggregates predominated in the striosomal compartment of the striatum, providing a possible explanation for the different neuronal vulnerability of striatal compartments observed in humans. The early motor phenotype observed in the knock-in mouse is reminiscent of repetitive movements often observed in early HD and provides a novel opportunity to assess the ability of therapies to prevent the initial effects of the mutation in vivo.

The role of blood microfilters in clinical practice

Blood filters have been available since the 1930s. In this review we evaluate the role of microaggregate filters (MF) in certain transfusion complications, namely non-haemolytic febrile transfusion reactions (NHFTR), pulmonary injury, thrombocytopenia, fibronectin depletion and histamine release. We review the latest generation of leucocyte depleting filters and discuss their role in preventing alloimmunisation, immunosuppression and CMV transmission. Finally, we provide a rationale for the role of blood microfiltration in the present day practice of intensive care medicine.