Nano ES GEMMA and PDMA, New Tools for the Analysis of Nanobioparticles—Protein Complexes, Lipoparticles, and Viruses

Differential mobility analysis (DMA) is a technique suited for size analysis as well as preparative collection of airborne nanosized airborne particles. In the recent decade, the analysis of intact viruses, proteins, DNA fragments, polymers, and inorganic nanoparticles was possible when combining this method with a nano-electrospray charge-reduction source for producing aerosols from a sample solution/suspensions. Mass analysis of high molecular weight noncovalent complexes is also possible with this methodology due to the linear correlation of the electrophoretic mobility diameter and the molecular mass. In this work, we present the analysis (size and molecular mass) of high molecular weight multimers (noncovalent functional homocomplex) of Jack bean urease in a mass range from 275 kDa up to 2.5 MDa, with mainly present tri- and hexamers but also higher oligomers of the 91 kDa monomer subunit. In a second experiment, the size analysis of intact very-low-density (∼35 nm), low-density (∼22 nm) and high-density lipoparticles (∼10 nm), which are heterocomplexes consisting of cholesterol, lipids, and proteins in different ratios, is presented. Results from mobility analysis were in excellent agreement with particle diameters found in literature. The last presented experiment demonstrates size analysis of a rod-like virus and selective sampling of a selected size fraction of electrosprayed, singly-charged tobacco mosaic virus particles. Sampling and subsequent transmission electron microscopic investigations of a specific size fraction (40 nm electrophoretic mobility diameter) revealed the folding of virus particles during the electrospray and charge reduction (electrical stress) as well as solvent evaporation (mechanical stress) process, leading to an observed geometry of 150 (length) × 35 (width) nm (average cylindrical geometry of unsprayed intact virus 300 × 18 nm)

Enhancing High-concentrated Wastewater Quality on Evaporation Rate from Five-Consecutive Oxidation Ponds as Located in Phetchaburi, Southerly Thailand

This research aimed to examine the environmental factors determining the rates of evaporation, a natural phenomenon contributing to the treatment of wastewater of 5-consecutive oxidation ponds of the King’s Royally Initiated Laem Phak Bia Environmental Research and Development Project. Data collected from the 17th of April to 30th of May 2019 by US Class A Evaporation Pan revealed that the sedimentation pond (Pond 1) has the highest rate, 7.22 mm d-1, the oxidation pond 1 (Pond 2), 5.70 mm d-1, the oxidation pond 3 (Pond 4), 5.56 mm d-1, the stabilization pond (Pond 5), mm d-1, the reference pond at 5.07 mm d-1 and the oxidation pond 2 (Pond 3), 3.59 mm d-1. Concluding the evaporation in domestic wastewater treatment plants is characterized by 1) heat generated from short and long wave radiation emitted by earth and the sun, 2) local wind profiles of the area affected the height differences of the roughness length, and 3) heat generated by the respiration and digestion process of microbial activities and other grey body contaminants. Presenting the day and night variations made for the analysis, the day evaporation was significantly higher resulted by the net radiation were accountable. Wind profile generated from the measurement of speeds and directions at two different sites at 3 and 10 m has explained for the roughness length heights over each pond as lower roughness height have cause the increased in the rates of evaporation in Pond 4 and 5 however, these processes were also suppressed by high ionic bonding molecules effected suggested by the high TDS and EC values. The vertical temperature profile has conveyed the movement in the heat flux that dominated an upward flux movement in Pond 1. This is the exothermic reaction from the digestion process have suggested that extra heat has been added

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

Dextran Nanoparticle Synthesis and Properties.

Dextran is widely exploited in medical products and as a component of drug-delivering nanoparticles (NPs). Here, we tested whether dextran can serve as the main substrate of NPs and form a stable backbone. We tested dextrans with several molecular masses under several synthesis conditions to optimize NP stability. The analysis of the obtained nanoparticles showed that dextran NPs that were synthesized from 70 kDa dextran with a 5% degree of oxidation of the polysaccharide chain and 50% substitution with dodecylamine formed a NP backbone composed of modified dextran subunits, the mean diameter of which in an aqueous environment was around 100 nm. Dextran NPs could be stored in a dry state and reassembled in water. Moreover, we found that different chemical moieties (e.g., drugs such as doxorubicin) can be attached to the dextran NPs via a pH-dependent bond that allows release of the drug with lowering pH. We conclude that dextran NPs are a promising nano drug carrier

Characterization of nanosized silica size standards

<p>Nanosized silica size standards produced with a sol–gel synthesis process were evaluated for particle size, effective density, and refractive index in this study. Particle size and effective density measurements were conducted following protocol from the National Institute of Advanced Industrial Science and Technology (AIST) in Japan. Particle sizes were measured via electrical mobility analysis using a differential mobility analyzer (DMA) at sheath flow rates (<i>Q</i>_sh) of 3.0 and 6.0 L/min and a constant aerosol flow rate (<i>Q</i>_a) of 0.3 L/min. The measured mean and mode diameters agreed well with the labeled sizes in the size range 40–200 nm, with differences ranging from 0.03% to 0.8%, well within the labeled expanded uncertainties (95% confidence intervals) of 1.8%–2.2%. The coefficient of variation (CV) of the size distribution was 0.012–0.027 for 40–200 nm. Particle sizes measured for 20 nm and 30 nm standards showed size differences with respect to the certified sizes of 1.7% and 8.3% at <i>Q</i>_sh = 6.0 L/min, but the size distributions were narrow, with CV = 0.047–0.064. The average effective density for the range 40–200 nm measured with an aerosol particle mass analyzer (APM) was 1.9 g/cm³. The real component of the refractive index measured with an optical particle counter (OPC) was 1.41 at a wavelength of 633 nm. All properties (size, effective density, and refractive index) were stable and could be measured with good repeatability. From these evaluations, it was found that the nanosized silica size standards have good characteristics for use as size standards and constitute a feasible alternative to PSL particles.</p> <p>© 2017 American Association for Aerosol Research</p

Assessment of urban green areas towards changing surface energy balance fluxes in tropical study sites, Central Thailand

The surface energy balance is broadly accepted as the interaction of the available energy fluxes that leads to the evaporation of surface water and an increase or decrease in the temperature of the surface and pertinent environment. This concept is widely utilized, shifting the increasing urbanization towards sustainable cities on a scientific basis for the planning and management of urban areas. Understanding the ambient factors governing energy fluxes will help mitigate the environmental burden linked to climate change by optimizing the layout of sustainable townships. For a quantitative description, we applied the eddy covariance method, which is one of the most widely accepted methods of monitoring flux changes, at different land-usage and surface-cover locations in an urban area (Kasetsart University (KU) tower), a rural natural mangrove forest environmental system (LERD project), and a spacious urban park estate (Bangkok, Bangkajao District). The results suggested that urban land usage has led to a shift in the ratios of energy fluxes, in which the proportion of latent heat in the mangrove forest area, Bangkajao Green Urban Park, and KU tower were 41%, 29%, and 22%, respectively. However, sensible heat at the KU tower, which is located in the denser urban areas of Bangkok, was predominant at 39% of the heat flux, whereas the transfer of energy into sensible heat in the LERD project and Bangkajao was 17% and 26%, respectively. This study reveals an increase in sensible heat in urban areas and a decrease in latent heat fluxes. Measurements linked to land-use classification showed that changes in the urban structure significantly contributed to heat in the spatial and temporal scales and indicated necessary avenues for the management of urban heat islands and mitigation of related adverse effects

Analysis of a Common Cold Virus and Its Subviral Particles by Gas-Phase Electrophoretic Mobility Molecular Analysis and Native Mass Spectrometry

Gas-phase electrophoretic mobility molecular analysis (GEMMA) separates nanometer-sized, single-charged particles according to their electrophoretic mobility (EM) diameter after transition to the gas-phase via a nano electrospray process. Electrospraying as a soft desorption/ionization technique preserves noncovalent biospecific interactions. GEMMA is therefore well suited for the analysis of intact viruses and subviral particles targeting questions related to particle size, bioaffinity, and purity of preparations. By correlating the EM diameter to the molecular mass (Mr) of standards, the Mr of analytes can be determined. Here, we demonstrate (i) the use of GEMMA in purity assessment of a preparation of a common cold virus (human rhinovirus serotype 2, HRV-A2) and (ii) the analysis of subviral HRV-A2 particles derived from such a preparation. (iii) Likewise, native mass spectrometry was employed to obtain spectra of intact HRV-A2 virions and empty viral capsids (B-particles). Charge state resolution for the latter allowed its Mr determination. (iv) Cumulatively, the data measured and published earlier were used to establish a correlation between the Mr and EM diameter for a range of globular proteins and the intact virions. Although a good correlation resulted from this analysis, we noticed a discrepancy especially for the empty and subviral particles. This demonstrates the influence of genome encapsulation (preventing analytes from shrinking upon transition into the gas-phase) on the measured analyte EM diameter. To conclude, GEMMA is useful for the determination of the Mr of intact viruses but needs to be employed with caution when subviral particles or even empty viral capsids are targeted. The latter could be analyzed by native MS. (Figure Presented)

Scheme of dextran modifications.

<p>Step 1: Oxidation, leading to opening of the glucose rings. Step 2: Schiff base formation between glucose carbonyl group and aliphatic amine.</p