Identification of Illicit Conservation Treatments in Fresh Fish by Micro-Raman Spectroscopy and Chemometric Methods

In the field of food control for fresh products, the identification of foods subjected to illicit conservation treatments to extend their shelf life is fundamental. Fresh fish products are particularly subjected to this type of fraud due to their high commercial value and the fact that they often have to be transported over a long distance, keeping their organoleptic characteristics unaltered. Treatments of this type involve, e.g., the bleaching of the meat and/or the momentary abatement of the microbial load, while the degradation process continues. It is therefore important to find rapid methods that allow the identification of illicit treatments. The study presented here was performed on 24 sea bass samples divided into four groups: 12 controls (stored on ice in the fridge for 3 or 24 h), and 12 treated with a Cafodos-like solution for 3 or 24 h. Muscle and skin samples were then characterized using micro-Raman spectroscopy. The data were pre-processed by smoothing and taking the first derivative and then PLS-DA models were built to identify short- and long- term effects on the fish's muscle and skin. All the models provided the perfect classification of the samples both in fitting and cross-validation and an analysis of the bands responsible for the effects was also reported. To the best of the authors' knowledge, this is the first time Raman spectroscopy has been applied for the identification of a Cafodos-like illicit treatment, focusing on both fish muscle and skin evaluation. The procedure could pave the way for a future application directly on the market through the use of a portable device

Impact of Beneficial Microorganisms on Strawberry Growth, Fruit Production, Nutritional Quality, and Volatilome

Arbuscular mycorrhizal fungi (AMF) colonize the roots of most terrestrial plant species, improving plant growth, nutrient uptake and biotic/abiotic stress resistance and tolerance. Similarly, plant growth promoting bacteria (PGPB) enhance plant fitness and production. In this study, three different AMF (Funneliformis mosseae, Septoglomus viscosum, and Rhizophagus irregularis) were used in combination with three different strains of Pseudomonas sp. (19Fv1t, 5Vm1K and Pf4) to inoculate plantlets of Fragaria × ananassa var. Eliana F1. The effects of the different fungus/bacterium combinations were assessed on plant growth parameters, fruit production and quality, including health-promoting compounds. Inoculated and uninoculated plants were maintained in a greenhouse for 4 months and irrigated with a nutrient solution at two different phosphate levels. The number of flowers and fruits were recorded weekly. At harvest, fresh and dry weights of roots and shoots, mycorrhizal colonization and concentration of leaf photosynthetic pigments were measured in each plant. The following fruit parameters were recorded: pH, titratable acids, concentration of organic acids, soluble sugars, ascorbic acids, and anthocyanidins; volatile and elemental composition were also evaluated. Data were statistically analyzed by ANOVA and PCA/PCA-DA. Mycorrhizal colonization was higher in plants inoculated with R. irregularis, followed by F. mosseae and S. viscosum. In general, AMF mostly affected the parameters associated with the vegetative portion of the plant, while PGPB were especially relevant for fruit yield and quality. The plant physiological status was differentially affected by inoculations, resulting in enhanced root and shoot biomass. Inoculation with Pf4 bacterial strain increased flower and fruit production per plant and malic acid content in fruits, while decreased the pH value, regardless of the used fungus. Inoculations affected fruit nutritional quality, increasing sugar and anthocyanin concentrations, and modulated pH, malic acid, volatile compounds and elements. In the present study, we show for the first time that strawberry fruit concentration of some elements and/or volatiles can be affected by the presence of specific beneficial soil microorganisms. In addition, our results indicated that it is possible to select the best plant-microorganism combination for field applications, and improving fruit production and quality, also in terms of health promoting properties

Rough surfaces with enhanced heat transfer for electronics cooling by direct metal laser sintering

Experimental evidences are reported on the potential of direct metal laser sintering (DMLS) in manufacturing flat and finned heat sinks with a remarkably enhanced convective heat transfer coefficient, taking advantage of artificial roughness in fully turbulent regime. To the best of our knowledge, this is the first study where artificial roughness by DMLS is investigated in terms of such thermal performances. On rough flat surfaces, we experience a peak of 73 % for the convective heat transfer enhancement (63 % on average) compared to smooth surfaces. On rough (single) finned surfaces, the best performance is found to be 40 % (35 % on average) compared to smooth finned surface. These results refer to setups with Reynolds numbers (based on heated edge) within 3,500 < Re_L < 16,500 (corresponding to 35,000 < Re_D < 165,000 in terms of Reynolds number based on hydraulic diameter). Experimental data are obtained by a purposely developed sensor with maximum and mean estimated tolerance intervals of +/- 7.0 % and +/- 5.4 %, respectively. Following the idea by Gioia et al. [Phys. Rev. Lett. 96 (2006) 044502], we propose that heat transfer close to the wall is dominated by eddies with size depending on the roughness dimensions and the viscous (Kolmogorov) length scale. An excellent agreement between the experimental data and the proposed analytical model is finally demonstrated

Blood transcriptomics of drug-na\uefve sporadic Parkinson's disease patients

BACKGROUND: Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder that is clinically defined in terms of motor symptoms. These are preceded by prodromal non-motor manifestations that prove the systemic nature of the disease. Identifying genes and pathways altered in living patients provide new information on the diagnosis and pathogenesis of sporadic PD. METHODS: Changes in gene expression in the blood of 40 sporadic PD patients and 20 healthy controls ("Discovery set") were analyzed by taking advantage of the Affymetrix platform. Patients were at the onset of motor symptoms and before initiating any pharmacological treatment. Data analysis was performed by applying Ranking-Principal Component Analysis, PUMA and Significance Analysis of Microarrays. Functional annotations were assigned using GO, DAVID, GSEA to unveil significant enriched biological processes in the differentially expressed genes. The expressions of selected genes were validated using RT-qPCR and samples from an independent cohort of 12 patients and controls ("Validation set"). RESULTS: Gene expression profiling of blood samples discriminates PD patients from healthy controls and identifies differentially expressed genes in blood. The majority of these are also present in dopaminergic neurons of the Substantia Nigra, the key site of neurodegeneration. Together with neuronal apoptosis, lymphocyte activation and mitochondrial dysfunction, already found in previous analysis of PD blood and post-mortem brains, we unveiled transcriptome changes enriched in biological terms related to epigenetic modifications including chromatin remodeling and methylation. Candidate transcripts as CBX5, TCF3, MAN1C1 and DOCK10 were validated by RT-qPCR. CONCLUSIONS: Our data support the use of blood transcriptomics to study neurodegenerative diseases. It identifies changes in crucial components of chromatin remodeling and methylation machineries as early events in sporadic PD suggesting epigenetics as target for therapeutic intervention

Surface Microstructuring for Control of Cellular Activities and Bio-Synthesized Cellulose Biolithography

Implants and medical devices constitute an essential part of state of the art medical treatments and therapies, contributing substantially to extend the average life expectancy and to improve its quality. The increment of age-related diseases and medical conditions together with the release of new medical products is expected to further boost the already growing trend of implantations. The increasing prevalence of these implants and the necessity of safe and efficient performances over long time periods demand for optimized solutions, not simply providing functionality in the short term. In fact, the design of the basic functionality of implants and medical devices (e.g. provide the desired flow rate for a pumping device or bear a specific maximum mechanical load for an orthopedic implant) is a challenging, but often solvable, issue. Not so is the integration of foreign objects in the human body. In fact, this has proven to be a limiting factor for their performances and long term efficiency. Integration in the body is an extremely complex issue: it is determined by the interplay between chemical, biochemical, mechanical and biological factors. Therefore each detail concerning the design of artificial device simultaneously and directly influences the outcome of such process. The complexity of the boundary conditions imposed by the human body, in which a device must work safely and efficiently, translates into the necessity to deal concurrently with different tissues and substances, in an complex transitioning between varying mechanical, chemical, thermal properties. This thesis aims at tackling the issue of integration of foreign materials in the human body, with special focus on the multiplicity of interfaces that medical devices expose to the living organisms. This complex problem is talked through with a multidisciplinary approach, combining the development of state of the art fabrication processes in the field of micro and nano engineering and biomaterials with principles of applied biology and mechanobiology. The research approach starts from the design of materials, continues with the detailing of a functional surface topography and a wide in vitro testing, to eventually end with an in vivo validation of the in vitro results and establishment of a robust proof of principle. In the first chapter, the problem of unspecific interaction between implantable materials and blood in devices assisting cardiac blood circulation is solved through the generation and sustenance under flow of a confluent and stable endothelial monolayer covering the luminal device surface, in a process defined as endothelialization. This process was supported by appropriate surface micro-structuring and that made it compatible with the supraphysiological wall shear stress (WSS) levels similar to those generated within vascular assist devices (VADs). Endothelialization could be achieved at supraphysiological WSS levels only by means of proper surface micro-structuring, not necessary at physiological WSS levels. Moreover, this work tested for the first time in a reliable and repeatable manner the exposure of endothelial cell layers to supraphysiological WSS conditions. This allowed to unravel a specific collective behavior of endothelial cells in these extreme conditions, with the cell layer pre-polarized by mean of microstructures orienting itself in the direction perpendicular to flow. In the following chapters, the focus of this work moves from the luminal surface to the external surface of implantable device, trying to provide novel insights and solutions to the issue of integration in soft tissues. In particular, the development of a new technology to produce and microstructure a biomaterial, namely bacterial or biosynthesized cellulose, its testing in vitro and in vivo are discussed. Particularly, in the second chapter, a powerful methodology to transfer functional topographies to the surface of bacterial cellulose membranes is presented. This method, named guided assembly-based biolithography (GAB), exploits the natural glucose fermentation process taking place in a static culture of Acetobacter xylinum to generate natively microstructured cellulose mats. The introduction of a surface-structured polydimethylsiloxane (PDMS) mold at the gas–liquid interface directed the deposition of cellulose nanofibers, generating a three-dimensional assembly with features replicating the ones on the elastomeric mold. GAB allowed to faithfully transfer micropatterns, achieving a certain degree of control on directional alignment of individual nanofibers. Preliminary in vitro testing with fibroblasts and keratinocytes not only proved the non-cytotoxicity of surface-structured bacterial cellulose, but also showed efficient control of cellular activities which are fundamental in skin wound healing and tissue regeneration. The implantation of surface-structured bacterial cellulose substrates in model animals proved also the high durability and low inflammatory response to the material. In the third chapter, GAB is extensively shown to produce textures able to significantly reduce cell adhesion. Biosynthesized cellulose is known to have very low affinity for proteins, offering therefore very limited and unstable binding sites for eukaryotic cells. The addition of appropriate surface microstructure significantly enhanced the already noteworthy reduction of cell adhesion on biosynthesized cellulose. Textures composed of isotropically distributed micro wells, ranging from 3 μm to 20 μm, were investigated using elastomeric PDMS samples and biosynthesized cellulose membranes. With such an approach, the effect of surface topography was completely decoupled from the role played by the other constitutive properties of the material. Considering the complex interplay of chemical signaling and mechanical cues characterizing the response of the body to any foreign material, the proposed patterns were tested in vitro with human dermal fibroblasts (HDFs) and THP-1 macrophages. A significant reduction of cell adhesion was observed for both fibroblasts and macrophages on microstructured cellulose, 63% and 80% respectively with respect to unstructured cellulose. Moreover, fibroblasts showed an unusual and not physiological morphology, with a pronounced reduction in proliferation. Macrophages presented a spherical shape, indicating low activation state, and gene expression confirmed no pro-inflammatory effect of biosynthesized cellulose, independently from the surface topography. Finally, the material proved durable and resistant to the in vivo environment, with clearly visible native microstructures after 3 months of dwelling in the thorax of a pig. Continuing on the same path, the fourth chapter is dedicated to the presentation of the in vivo pre-clinical study in large animals of a big surface microstructured biosynthesized cellulose membrane to reduce the formation of fibrotic tissue surrounding pacemakers. The study was performed in large animals, with full scale commercial devices and state of the art surgical tools and procedures. Microstructured biosynthesized cellulose membranes caused a reduction of approximately 45% of the thickness of the layer of fibrotic tissue encapsulating the devices. Importantly, the material did not cause a systematic increment of the inflammatory response, remaining physically stable and unchanged for periods as long as 13 weeks in large animals. Moreover, in addition to the reduction of the thickness of the fibrotic capsule, the newly developed concept and surgical procedure offer a completely new opportunity to surgeons for a facile revision surgical procedure or for battery exchange procedure

Ettore Majorana. Aspects of his Scientific and Academic Activity

none2GUERRA F; N. ROBOTTIGuerra, F; Robotti, Nadi

Enrico Fermi e il quaderno ritrovato: 20 marzo 1934 : la vera storia della scoperta della radioattività indotta da neutroni

La scoperta della radioattività indotta da neutroni ha aperto all'umanità nuove frontiere nel campo della conoscenza scientifica. Il ritrovamento del corrispondente quaderno di laboratorio di Enrico Fermi ha permesso una precisa ricostruzione di tale scoperta, finora basata essenzialmente su testimonianze dirette o indirette, con tutti i limiti tipici del ricordo personale