AirMLP: A Multilayer Perceptron Neural Network for Temporal Correction of PM2.5 Values in Turin.

In recent times, pollution has emerged as a significant global concern, with European regulations stipulating limits on PM 2.5 particle levels. Addressing this challenge necessitates innovative approaches. Smart low-cost sensors suffer from imprecision, and can not replace legal stations in terms of accuracy, however, their potential to amplify the capillarity of air quality evaluation on the territory is not under discussion. In this paper, we propose an AI system to correct PM 2.5 levels in low-cost sensor data. Our research focuses on data from Turin, Italy, emphasizing the impact of humidity on low-cost sensor accuracy. In this study, different Neural Network architectures that vary the number of neurons per layer, consecutive records and batch sizes were used and compared to gain a deeper understanding of the network's performance under various conditions. The AirMLP7-1500 model, with an impressive R-squared score of 0.932, stands out for its ability to correct PM 2.5 measurements. While our approach is tailored to the city of Turin, it offers a systematic methodology for the definition of those models and holds the promise to significantly improve the accuracy of air quality data collected from low-cost sensors, increasing the awareness of citizens and municipalities about this critical environmental information.

Field-Flow Fractionation in Molecular Biology and Biotechnology.

Field-flow fractionation (FFF) is a family of single-phase separative techniques exploited to gently separate and characterize nano- and microsystems in suspension. These techniques cover an extremely wide dynamic range and are able to separate analytes in an interval between a few nm to 100 µm size-wise (over 15 orders of magnitude mass-wise). They are flexible in terms of mobile phase and can separate the analytes in native conditions, preserving their original structures/properties as much as possible. Molecular biology is the branch of biology that studies the molecular basis of biological activity, while biotechnology deals with the technological applications of biology. The areas where biotechnologies are required include industrial, agri-food, environmental, and pharmaceutical. Many species of biological interest belong to the operational range of FFF techniques, and their application to the analysis of such samples has steadily grown in the last 30 years. This work aims to summarize the main features, milestones, and results provided by the application of FFF in the field of molecular biology and biotechnology, with a focus on the years from 2000 to 2022. After a theoretical background overview of FFF and its methodologies, the results are reported based on the nature of the samples analyzed.

Monitoring effects of hydrodynamic cavitation pretreatment of sodium oleate on the aggregation of fine diaspore particles through small-angle laser scattering.

Hydrodynamic cavitation (HC) enhanced fine particle aggregation could be largely due to the generation of tiny bubbles and their role in bridging particles. However, the lack of adequate characterizations of aggregates severally limits our further understanding of the associated aggregation behaviors. In this study, the aggregation of fine diaspore particles was comparatively investigated in sodium oleate (NaOl) solutions with and without HC pretreatment through the small-angle laser scattering (SALS) technique in a shear-induced aggregation (SIA) system. Results showed that HC pretreatment caused the formation of bulk nanobubbles (BNBs), which significantly modified the particle interactions and thereby modified the size and mass fractal dimension (Df) of aggregates under different SIA conditions. Although HC pretreatment did not noticeably alter the gradual change trend of aggregate size and structure characteristics under specific variables, BNBs bridging facilitated the aggregation process towards the diffusion-limited cluster aggregation model, resulting in the formation of larger but looser aggregates. This effect was more pronounced under relatively high NaOl concentrations. Apart from BNBs, the aggregation was also affected by cavitation bubbles formed during shear cavitation, which was more significant under high stirring intensity conditions (i.e., 1800 rpm) than the low stirring intensity conditions (i.e., 600 rpm).

Laser scattering centrifugal liquid sedimentation method for the accurate quantitative analysis of mass-based size distributions of colloidal silica.

This paper proposes a laser scattering centrifugal liquid sedimentation (LS-CLS) method for the accurate quantitative analysis of the mass-based size distributions of colloidal silica. The optics comprised a laser diode light source and multi-pixel photon-counting detector for detecting scattered light intensity. The unique optics can only detect the light scattered by a sample through the interception of irradiated light. The developed centrifugal liquid sedimentation (CLS) method comprised a light-emitting diode and silicon photodiode detector for detecting transmittance light attenuation. The CLS apparatus could not accurately measure quantitative volume- or mass-based size distribution of poly-dispersed suspensions, such as colloidal silica, because the detecting signal includes both transmitted and scattered light. The LS-CLS method exhibited improved quantitative performance. Moreover, the LS-CLS system allowed the injection of samples with concentrations higher than that permitted by other particle size distribution measurement systems with particle size classification units using size-exclusion chromatography or centrifugal field-flow fractionation. The proposed LS-CLS method achieved an accurate quantitative analysis of the mass-based size distribution using both centrifugal classification and laser scattering optics. In particular, the system could measure the mass-based size distribution of approximately 20 mg mL-1 poly-dispersed colloidal silica samples, such as in a mixture of the four mono-dispersed colloidal silica, with high resolution and precision, thereby demonstrating high quantitative performance. The measured size distributions were compared with those observed through transmission electron microscopy. The proposed system can be used in practical setups to achieve a reasonable degree of consistency for determining particle size distribution in industrial applications.

Interaction of DPPC liposomes with cholesterol and food protein during in vitro digestion using Dynamic Light Scattering and FTIR spectroscopy analysis.

The influence of cholesterol (CHO), bovine serum albumin (BSA) and lactoferrin (LF), on the phase transition temperature (Tm) and structure of DPPC liposomes during in vitro digestion was investigated using Dynamic Laser Scattering (DLS) and Fourier Transform Infrared Spectroscopy technologies (FTIR). CHO enhanced bilayers thickness and acyl chain order, especially in DPPC:CHO of 6:1, with the average size increase to 1.77 ± 0.20 µm and broaden of phase transition (Tm 45.8 °C). Protein critically impacted on the liposomal structure through formation of hydrogen bonds between in DPPC and protein. Liposomal size and Tm were significantly changed after simulated gastric digestion, whereas the pancreatic incubation can broaden transition phase and weaken functional groups of liposomes. Our data provided a better understanding on structure changes of CHO-containing membrane and protein addition by revealing Tm and chemical bonds details, and added to current knowledge for evaluating the different component on liposomal digestibility in food area.

In Situ Optical Studies on Morphology Formation in Organic Photovoltaic Blends.

The efficiency of bulk heterojunction (BHJ) based organic solar cells is highly dependent on the morphology of the blend film, which is a result of a fine interplay between donor, acceptor, and solvent during the film drying. In this work, a versatile set-up of in situ spectroscopies is used to follow the morphology evolution during blade coating of three iconic BHJ systems, including polymer:fullerene, polymer:nonfullerene small molecule, and polymer:polymer. the drying and photoluminescence quenching dynamics are systematically study during the film formation of both pristine and BHJ films, which indicate that the component with higher molecular weight dominates the blend film formation and the final morphology. Furthermore, Time-resolved photoluminescence, which is employed for the first time as an in situ method for such drying studies, allows to quantitatively determine the extent of dynamic and static quenching, as well as the relative change of quantum yield during film formation. This work contributes to a fundamental understanding of microstructure formation during the processing of different blend films. The presented setup is considered to be an important tool for the future development of blend inks for solution-cast organic or hybrid electronics.

Aerosol Droplet Surface Measurement Methods.

Aerosol droplets play a critical role in the development of weather patterns, yet are notoriously difficult to analyze because of their small size, transient nature and potentially complex composition. As a result, there has been a surge in recent years in the development of analysis techniques aimed at the study of aerosol droplets, namely of their surface tension properties, which are thought to play a great role in aerosol/cloud growth and subsequently having an impact on the resulting weather patterns. To capture the state of the field at this key time, we have collected and described some of the most relevant and influential studies, with a focus on those that have had the most impact. This review will present and describe the most used analytical techniques for studying the surface tension of micrometer-sized aqueous droplets, with a focus on historical trends and how the current techniques are posed to revolutionize the field.

An experimental application of laser-scattering sensor to estimate the traffic-induced PM2.5 in Beijing.

Traffic-induced air pollutant emissions are currently rising rapidly. However, measurement of the roadside environment and calculation of the emission factors for traffic-induced PM2.5 are restricted to certain locations and periods due to the limitations of conventional air monitoring techniques. This paper introduces a portable sensor package with a laser light-scattering PM2.5 sensor and an electrochemical CO sensor to measure roadside PM2.5 and CO concentrations. The low-cost sensor package underwent local calibration using reference instruments at the Chinese Research Academy of Environmental Sciences (CRAES). The results showed a high level of correlation (r in the range of 0.94-0.95 and 0.81-0.83 for PM2.5 and CO, respectively) between measurements using the sensor packages and those measured by the reference equipment. The study found that the low-cost sensor packages were able to deliver reliable measurements of PM2.5 and CO concentrations. Four low-cost sensor packages were deployed along a short section of an expressway to measure roadside PM2.5 and CO concentrations. The directly measured concentrations were firstly calibrated with the temperature and humidity. The corrected PM2.5 concentrations from each side of the road were different, while the corrected CO concentrations were similar on both sides of the road. Therefore, only the PM2.5 measurements were applied in this study's box model. The assumption of perfect mixing in order for the box model to be applied was shown by the results to be valid to some extent. The PM2.5 emission factors for opposite sides of the road should be calculated separately based on the direction of traffic flow. The PM2.5 emission factors calculated in this study were variable, being impacted by traffic conditions and meteorological conditions. The paper presents a method for obtaining PM2.5 emission factors based on a box model. This method is a promising way of monitoring air pollution in the roadside environment.

Investigating the potential of utilizing glycerosomes as a novel vesicular platform for enhancing intranasal delivery of lacidipine.

Lacidipine is a potent dihydropyridine calcium channel blocker used for management of hypertension and atherosclerosis. The drug has low and fluctuating oral bioavailability owing to its extensive hepatic first-pass metabolism and reduced water solubility. Accordingly, this work aimed at overcoming the aforementioned challenges through the formulation of intranasal nano-sized lacidipine glycerosomes. Box-Behnken was successfully employed for the formulation and in vitro optimization of the glycerosomes. Statistical analysis revealed that cholesterol concentration exhibited a significant effect on the vesicle size, while Phospholipon® 90G and glycerol concentrations exhibited significant effects on both entrapment efficiency and deformability index. The optimized formulation showed spherical shape, good deformability, vesicular size of 220.25 nm, entrapment efficiency of 61.97%, and enhanced ex vivo permeation by 3.65 fold compared to lacidipine suspension. Confocal laser scattering microscope revealed higher penetration depth via nasal mucosa for rhodamine labelled glycerosomes (up to 60 µm) in comparison to rhoadamine dye solution (26 µm). In addition, the optimized lacidipine glycerosomes caused significant reduction in methylprednisolone acetate-induced hypertension in rats for up to 24 h in comparison to oral drug suspension. Histopathological assessment showed intact nasal mucosal epithelial lining with no signs of inflammation or necrosis confirming the safety and tolerability of the proposed glycerosomes. The declared results highlights the potential of utilizing the proposed glycerosomes as safe and effective platform for intranasal delivery of lacidipine.

Application of a thermophoretic immunoassay in the diagnosis of lupus using outer membrane particles from E. coli.

Thermophoresis is the physical diffusion of molecules from hot to cold induced by a thermal gradient. Thermophoresis has been used to evaluate the interaction of biomolecules in solution. In this study, the outer membrane from E. coli was isolated and used to produce OM particles with a diameter of approximately 100 nm. These prepared OM particles were applied in a thermophoretic immunoassay. First, outer membrane (OM) particles with lipopolysaccharides (LPS) and anti-LPS antibodies were used as a model to demonstrate proof of concept and the difference in E. coli thermophoresis was explained by the changes in the molecular surface area (A) and effective charge (σeff). The hydrodynamic size of the molecules was measured as a changing parameter, molecular surface area (A), by dynamic laser scattering (DLS), and the zeta potential was measured as a changing parameter of effective charge (σeff) and then evaluated by the Soret equation. Using the hydrodynamic size and zeta potential values, the interaction between the antigen (OM particle with LPS) and antibody (anti-LPS antibodies) could be monitored and the results were fitted to the thermophoretic immunoassay using the Soret coefficient and equation. Finally, this OM-based immunoassay was applied to the medical diagnosis of systemic lupus erythematosus. Here, OM particles with Ro and La proteins were used to analyze the autoantibodies in patient and control sera. Thermophoretic immunoassay results were also compared to the fitted analysis using hydrodynamic size and zeta potential values and the Soret coefficient and equation.

Integrated Laser Sensor (ILS) for Remote Surface Analysis: Application for Detecting Explosives in Fingerprints.

Here, we describe an innovative Integrated Laser Sensor (ILS) that combines four spectroscopic techniques and two vision systems into a unique, transportable device. The instrument performs Raman and Laser-Induced Fluorescence (LIF) spectroscopy excited at 355 nm and Laser-Induced Breakdown Spectroscopy (LIBS) excited at 1064 nm, and it also detects Laser Scattering (LS) from the target under illumination at 650 nm. The combination of these techniques supplies information about: material change from one scanning point to another, the presence of surface contaminants, and the molecular and elemental composition of top target layers. Switching between the spectroscopic techniques and the laser wavelengths is fully automatic. The instrument is equipped with an autofocus, and it performs scanning with a chosen grid density over an interactively-selected target area. Alternative to the spectroscopic measurements, it is possible to switch the instrument to a high magnification target viewing. The working distances tested until now are between 8.5 and 30 m. The instrument is self-powered and remotely controlled via wireless communication. The ILS has been fully developed at ENEA for security applications, and it was successfully tested in two outdoor campaigns where an automatic recognition of areas containing explosives in traces had been implemented. The strategies for the identification of nitro-compounds placed on various substrates as fingerprints and the results obtained at a working distance of 10 m are discussed in the following.

Parallel chromatography and in situ scattering to interrogate competing protein aggregation pathways.

Protein aggregation can follow different pathways, and these can result in different net aggregation rates and kinetic profiles. α-chymotypsinogen A (aCgn) was used as a model system to quantitatively and qualitatively assess an approach that combines ex situ size-exclusion chromatography (SEC) with in situ laser scattering (LS) to monitor aggregation vs. time. Aggregation was monitored for a series of temperatures and initial dimer (ID) levels for starting conditions that were primarily (> 97%) monomer, and under initial-rate conditions (limited to low monomer conversion-less than 20% monomer mass loss), as these conditions are of most to interest to many pharmaceutical and biotechnology applications. SEC results show that modest decreases of ID levels can greatly reduce monomer loss rates, but do not affect the effective activation energy for aggregation. The normalized aggregation rates determined from LS were typically ∼ 1 order of magnitude higher than the corresponding rates from SEC. Furthermore, LS signals vs. time became variable and highly nonlinear with decreasing ID level, temperature, and/or total protein concentration. Temperature-cycling LS experiments showed this corresponded to conditions where dimer/oligomer "seeding" was suppressed, and high levels of reversible oligomers ("prenuclei") were formed prior to "nucleation" and growth of stable aggregates. In those conditions, aggregation rates inferred from LS and SEC are greatly different, as the techniques monitor different stages of the aggregation process. Overall, the results illustrate an approach for interrogating non-native protein aggregation pathways, and potential pitfalls if one relies on a single method to monitor aggregation-this holds more generally than the particular methods here.

Direct determination of carbapenem-resistant Enterobacteriaceae and Pseudomonas aeruginosa from positive blood cultures using laser scattering technology.

Delays in appropriate antimicrobial treatment contribute to increased mortality of septic patients. We aimed to develop a methodology for detection of carbapenem resistance in Gram-negative bacteria directly from positive blood cultures (BCs). Initially, meropenem-resistant Enterobacteriaceae (n = 13) and Pseudomonas aeruginosa (n = 32) isolates as well as the same numbers of meropenem-susceptible isolates were used to establish the detection of carbapenem resistance from agar cultures. Growth-based phenotypic detection of meropenem resistance was performed by a laser scattering (LS) method using a BacterioScan™216R instrument. A subset of the strain collection consisting of meropenem-susceptible and -resistant isolates (each comprising seven P. aeruginosa and three Klebsiella pneumoniae) was used for determination of carbapenem resistance directly from positive BCs. Lysis/centrifugation and filtration/dilution methods were investigated for processing of positive BCs. Four different statistical approaches to discriminate between susceptible and resistant bacteria in real-time were applied and were compared regarding their sensitivity and specificity. After 3 h and 4 h of incubation, respectively, detection of carbapenem resistance in Enterobacteriaceae (sensitivity, 100%; specificity, 100%) and P. aeruginosa (sensitivity, 100%; specificity, ≥90%) agar cultures was attainable. Detection of carbapenem resistance directly from positive BCs was achievable with 100% sensitivity and 100% specificity after 4 h and 5 h, respectively, applying lysis/centrifugation and filtration/dilution methods. In conclusion, LS technology combined with lysis/centrifugation and appropriate statistical real-time analyses represents a promising option for rapid detection of carbapenem resistance in Gram-negative rods directly from positive BCs.

Rapid Phenotypic Detection of Microbial Resistance in Gram-Positive Bacteria by a Real-Time Laser Scattering Method.

We developed a methodology for antimicrobial susceptibility testing (AST) based on the BacterioScanTM216R laser scattering technology, using methicillin resistance in Staphylococcus aureus and vancomycin resistance in enterococci as exemplar for important resistance phenotypes. Fifty methicillin-resistant (MRSA) and 50 methicillin-susceptible (MSSA) S. aureus, as well as 50 vancomycin-resistant enterococci (VRE) and 50 vancomycin-susceptible enterococci (VSE) isolates were used for the study. Optimal test conditions were derived by investigating the effects of inoculum size, medium, incubation temperature and broth filtration. We proposed four different statistical approaches for rapid discrimination between resistant and susceptible bacteria. The statistical approach based on raw measurements of bacterial concentrations delivered sensitivity of 100% and specificity of 94% for discrimination between MRSA and MSSA already after 3 hours of incubation. Categorical agreement of ≥90% was achieved after 140 min with this approach. Differentiation between VRE and VSE was possible with 98% sensitivity and 92% specificity after 3 hours, using a sophisticated statistical approach based on concentration slopes derived from the raw concentration measurements. This approach provided categorical agreement of ≥90% after 165 min. The sensitivity and specificity estimates were confirmed by leave-one-out cross validation. In conclusion, the phenotypic AST methods developed in this study are promising for rapid detection of MRSA and VRE. The development and application of this technology would allow early detection of the resistant pathogens, thus facilitating swift change to the targeted antimicrobial treatment as well as timely initiation of appropriate infection control measures. Further studies are warranted to validate this approach for the detection of other resistance phenotypes, including direct testing from clinical specimens.

Identifying protein aggregation mechanisms and quantifying aggregation rates from combined monomer depletion and continuous scattering.

Parallel temperature initial rates (PTIR) from chromatographic separation of aggregating protein solutions are combined with continuous simultaneous multiple sample light scattering (SMSLS) to make quantitative deductions about protein aggregation kinetics and mechanisms. PTIR determines the rates at which initially monomeric proteins are converted to aggregates over a range of temperatures, under initial-rate conditions. Using SMSLS for the same set of conditions provides time courses of the absolute Rayleigh scattering ratio, IR(t), from which a potentially different measure of aggregation rates can be quantified. The present report compares these measures of aggregation rates across a range of solution conditions that result in different aggregation mechanisms for anti-streptavidin (AS) immunoglobulin gamma-1 (IgG1). The results illustrate how the two methods provide complementary information when deducing aggregation mechanisms, as well as cases where they provide new mechanistic details that were not possible to deduce in previous work. Criteria are presented for when the two techniques are expected to give equivalent results for quantitative rates, the potential limitations when solution non-idealities are large, as well as a comparison of the temperature dependence of AS-IgG1 aggregation rates with published data for other antibodies.

Dynamic measurement of starch granule swelling during microwave heating.

The size of starch granules in dilute aqueous suspension was measured in-line during gelatinization in a microwave-heated, well-mixed system. The results were compared with those of a previous study conducted with conventional heating. For the starches used (common corn, waxy maize, and cross-linked waxy maize), no significant difference was found between microwave and conventional heating in terms of maximum diameter, temperature of maximum rate of diameter increase, or diameter vs. temperature behavior. These results suggest that there are no differences in the swelling behavior of common and modified maize starches between microwave and conventional heating.

Effects of halide ions on the acceptor phase in spontaneous chemical oscillations in donor/membrane/acceptor systems.

The effects of halide ions on the acceptor phase in the chemical oscillation in donor/membrane/acceptor systems were examined. The transfer of cetyltrimethylammonium (CTA(+)) ions from the donor phase and their adsorption and desorption at the membrane/acceptor interface led to spontaneous, nonlinear oscillations of the electric potential. Chloride ions stabilized the adsorption of CTA(+) ions and gave rise to a large-amplitude, long-interval, and a long relaxation-time constant. On the contrary, iodide ions, which are more hydrophobic than chloride ions, demonstrated opposite results. This mechanism was proposed based on the simultaneous time-resolved measurements of the interfacial tensions at both the donor/membrane and membrane/acceptor interfaces and observation of the convective flow due to Marangoni instability.

Rapid identification and classification of Campylobacter spp. using laser optical scattering technology.

Campylobacter jejuni and Campylobacter coli are the two important species responsible for most of the Campylobacter infections in humans. Reliable isolation and detection of Campylobacter spp. from food samples are challenging due to the interferences from complex food substances and the fastidious growth requirements of this organism. In this study, a novel biosensor-based detection called BARDOT (BActerial Rapid Detection using Optical scattering Technology) was developed for high-throughput screening of Campylobacter colonies grown on an agar plate without disrupting the intact colonies. Image pattern characterization and principal component analysis (PCA) of 6909 bacterial colonies showed that the light scatter patterns of C. jejuni and C. coli were strikingly different from those of Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. Examination of a mixed culture of these microorganisms revealed 85% (34/40) accuracy in differentiating Campylobacter from the other three major foodborne pathogens based on the similarity to the scatter patterns in an established library. The application of BARDOT in real food has been addressed through the analysis of Campylobacter spiked ground chicken and naturally contaminated fresh chicken pieces. Combined with real-time PCR verification, BARDOT was able to identify Campylobacter isolates from retail chicken. Moreover, applying passive filtration to food samples facilitated the isolation of pure Campylobacter colonies and therefore overcame the interference of the food matrix on BARDOT analysis.

An integrated buccal delivery system combining chitosan films impregnated with peptide loaded PEG-b-PLA nanoparticles.

Peptide (insulin) loaded nanoparticles (NPs) have been embedded into buccal chitosan films (Ch-films-NPs). These films were produced by solvent casting and involved incorporating in chitosan gel (1.25% w/v), NPs-Insulin suspensions at three different concentrations (1, 3, and 5mg of NPs per film) using glycerol as plasticiser. Film swelling and mucoadhesion were investigated using 0.01M PBS at 37°C and texture analyzer, respectively. Formulations containing 3mg of NPs per film produced optimised films with excellent mucoadhesion and swelling properties. Dynamic laser scattering measurements showed that the erosion of the chitosan backbone controlled the release of NPs from the films, preceding in vitro drug (insulin) release from Ch-films-NPs after 6h. Modulated release was observed with 70% of encapsulated insulin released after 360h. The use of chitosan films yielded a 1.8-fold enhancement of ex vivo insulin permeation via EpiOral™ buccal tissue construct relative to the pure drug. Flux and apparent permeation coefficient of 0.1µg/cm(2)/h and 4×10(-2)cm(2)/h were respectively obtained for insulin released from Ch-films-NPs-3. Circular dichroism and FTIR spectroscopy demonstrated that the conformational structure of the model peptide drug (insulin) released from Ch-films-NPs was preserved during the formulation process.

Effects of lung exposure to carbon nanotubes on female fertility and pregnancy. A study in mice.

We studied the effects of preconceptional exposure to multiwalled carbon nanotubes (MWCNTs): mature, female C57BL/6J mice were intratracheally instilled with 67µg NM-400 MWCNT, and the following day co-housed with mature males, in breeding pairs. Time to delivery of the first litter, litter parameters, maternal inflammation and histopathology of lung and liver were recorded. In male offspring, locomotor activity, startle response, and daily sperm production (DSP) were assessed. In the dams, lung and liver bore evidence of MWCNT exposure when assessed 6 weeks and 4 months after exposure. A short delay in the delivery of the first litter was observed in exposed females. Litter parameters, behavior and DSP were similar in control and exposed groups. In conclusion, instillation of a single dose of MWCNT induced long lasting pathological changes in dam lung and liver. Theoretically, lung inflammation due to particle exposure could interfere with female reproductive parameters. Whether the observed lag in delivery of a first litter was in fact caused by exposure to MWCNT should be addressed in a study designed specifically to elucidate effects on the early processes involved in establishment of pregnancy. Exposure was not associated with changes in the assessed gestational or offspring parameters.