Effect of ratio between volume and surface area of airships

The ratio between the volume and the surface area also exerts an influence on other secondary characteristics of airships, which I will here briefly indicate

Replacing the weight of materials consumed on airships

Two methods to replace the weight of gas lost on long airship flights are discussed: condensing the water of combustion and thermic sustentation. In the present article we will discuss the first method, leaving the second to be examined in a subsequent article

Structural and Economic Limits to the Dimensions of Airships

In opposition to the advantage of larger dimensions, there is one disadvantage, namely, the weight of the structure increases more rapidly than the buoyancy. It is not possible, however, to determine a general law. In order to formulate one having the merit of simplicity, we will divide the structure into two parts: one subject to tensile and compressive stresses, varying directly as the ascensional or lifting forces; the other subject to varying stresses of the surface areas

Studies on the Biosynthesis of Some Furocoumarins Present in Ruta graveolens

The biosynthesis of some furocoumarins present in Ruta graveolens has been studied administering labeled psoralen, xanthotoxin, rutaretin, marmesin and 7-hydroxycoumarin-derivatives. The results obtained indicate that the biosynthetic pathway involves not only psoralen, but also xanthotoxin and bergapten, by means of methoxylation or demethoxylation reactions. Moreover results achieved from administering rutaretin demonstrate that this substance is a new very effective natural precursor for xanthotoxin; in a parallel way marmesin is incorporated into psoralen. The reported results indicate that also at the stage of natural 4′,5′-dihydrofurocoumarins intermediates an interconversion can occur. Finally the essential role of umbelliferone in the biosynthesis of furocoumarins has been confirmed

Contribution of polymorphic variation of inositol hexakisphosphate kinase 3 (IP6K3) gene promoter to the susceptibility to late onset Alzheimer's disease

Maintenance of electric potential and synaptic transmission are energetically demanding tasks that neuronal metabolism must continually satisfy. Inability to fulfil these energy requirements leads to the development of neurodegenerative disorders, including Alzheimer's disease. A prominent feature of Alzheimer's disease is in fact neuronal glucose hypometabolism. Thus understanding the fine control of energetic metabolism might help to understand neurodegenerative disorders. Recent research has indicated that a novel class of signalling molecules, the inositol pyrophosphates, act as energy sensors. They are able to alter the balance between mitochondrial oxidative phosphorylation and glycolytic flux, ultimately affecting the cellular level of ATP. The neuronal inositol pyrophosphate synthesis relies on the activity of the neuron enriched inositol hexakisphosphate kinase 3 (IP6K3) enzyme. To verify an involvement of inositol pyrophosphate signalling in neurodegenerative disorders, we performed tagging single nucleotide polymorphism (SNP) analysis of the IP6K3 gene in patients with familial and sporadic late onset Alzheimer's disease (LOAD). Two SNPs in the 5'-flanking promoter region of the IP6K3 gene were found to be associated with sporadic LOAD. Characterizing the functionality of the two polymorphisms by luciferase assay revealed that one of them (rs28607030) affects IP6K3 promoter activity, with the G allele showing an increased activity. As the same allele has a beneficial effect on disease risk, this may be related to upregulation of IP6K3 expression, with a consequent increase in inositol pyrophosphate synthesis. In conclusion, we provide the first evidence for a contribution of genetic variability in the IP6K3 gene to LOAD pathogenesis

A Simple Microwave Imaging System for Food Product Inspection through a Symmetry-Based Microwave Imaging Approach

In the food industry, there is a growing demand for cost-effective methods for the inline inspection of food items able to non-invasively detect small foreign bodies that may have contaminated the product during the production process. Microwave imaging may be a valid alternative to the existing technologies, thanks to its inherently low-cost and its capability of sensing low-density contaminants. In this paper, a simple microwave imaging system specifically designed to enable the inspection of a large variety of food products is presented. The system consists of two circularly loaded antipodal Vivaldi antennas with a very large operative band, from 1 to 15 GHz, thus allowing a suitable spatial resolution for different food products, from mostly fatty to high water-content foods. The antennas are arranged in such a way as to collect a signal that can be used to exploit a recently proposed real-time microwave imaging strategy, leveraging the inherent symmetries that usually characterize food items. The system is experimentally characterized, and the achieved results compare favorably with the design specifications and numerical simulations. Relying on these positive results, the first experimental proof of the effectiveness of the entire system is presented confirming its efficacy

Non-Destructive Characterization of Magnetic Polymeric Scaffolds using Terahertz Time-of-Flight Imaging

Magnetic Scaffolds MagS are 3D composite materials, in which magnetic nanoparticles (MNPs) are used to load a polymeric matrix. Due to their wide use in various medical applications, there is an increasing demand of advanced techniques for non-destructive quality assessment procedures aimed at verifying the absence of defects and, more generally, dedicated to the characterization of MagS. In this framework, the use of TeraHertz (THz) waves for the non-destructive characterization of multifunctional scaffolds represents an open challenge for the scientific community. This paper deals with an approach for the characterization of MagS by means of a THz time-domain system used in reflection mode. THz analyses are performed on poly($\epsilon$ - capprolactone) (PCL) scaffolds magnetized with iron oxide (Fe $_{3}$ O$_{4}$) MNPs through a drop-casting deposition and tuned to obtain different distributions of MNP in the biomaterial. The proposed data processing approach allows a quantitative characterization MagS, in terms of their (estimated) thickness and refractive index. Moreover, the proposed procedure allows to identify the areas of the scaffold wherein MNP are mainly concentrated and thus, it gives us information about MNP spatial distribution

IP6K3 and IPMK variations in LOAD and longevity: evidence for a multifaceted signaling network at the crossroad between neurodegeneration and survival

Several studies reported that genetic variants predisposing to neurodegeneration were at higher frequencies in centenarians than in younger controls, suggesting they might favor also longevity. IP6K3 and IPMK regulate many crucial biological functions by mediating synthesis of inositol poly- and pyrophosphates and by acting non-enzymatically via protein–protein interactions. Our previous studies suggested they affect Late Onset Alzheimer Disease (LOAD) and longevity, respectively. Here, in the same sample groups, we investigated whether variants of IP6K3 also affect longevity, and variants of IPMK also influence LOAD susceptibility. We found that: i) a SNP of IP6K3 previously associated with increased risk of LOAD increased the chance to become long-lived, ii) SNPs of IPMK, previously associated with decreased longevity, were protective factors for LOAD, as previously observed for UCP4. SNP-SNP interaction analysis, including our previous data, highlighted phenotype-specific interactions between sets of alleles. Moreover, linkage disequilibrium and eQTL data associated to analyzed variants suggested mitochondria as crossroad of interconnected pathways crucial for susceptibility to neurodegeneration and/or longevity. Overall, data support the view that in these traits interactions may be more important than single polymorphisms. This phenomenon may contribute to the non-additive heritability of neurodegeneration and longevity and be part of the missing heritability of these traits

Preliminary In-Line Microwave Imaging Experimental Assessment for Food Contamination Monitoring

Food producers must deal with contaminants (wood, plastic, glass) inside packaged products that could lead to customer dissatisfaction. The assessed technologies fail to detect some of these contaminants, leading to the need for new technologies with different signal qualities, such as microwave sensing. This paper presents a preliminary result of a microwave imaging system designed for industrial applications. The measurement system was designed for and works on an industrial conveyor belt where packaged products are scanned. The scanned signals are processed to obtain an accurate 3D image of the size and position of the contaminant inside the food package. In addition to the results, we describe the implemented system and some considerations on data acquisition

Cancellation of vorticity in steady-state non-isentropic flows of complex fluids

In steady-state non-isentropic flows of perfect fluids there is always thermodynamic generation of vorticity when the difference between the product of the temperature with the gradient of the entropy and the gradient of total enthalpy is different from zero. We note that this property does not hold in general for complex fluids for which the prominent influence of the material substructure on the gross motion may cancel the thermodynamic vorticity. We indicate the explicit condition for this cancellation (topological transition from vortex sheet to shear flow) for general complex fluids described by coarse-grained order parameters and extended forms of Ginzburg-Landau energies. As a prominent sample case we treat first Korteweg's fluid, used commonly as a model of capillary motion or phase transitions characterized by diffused interfaces. Then we discuss general complex fluids. We show also that, when the entropy and the total enthalpy are constant throughout the flow, vorticity may be generated by the inhomogeneous character of the distribution of material substructures, and indicate the explicit condition for such a generation. We discuss also some aspects of unsteady motion and show that in two-dimensional flows of incompressible perfect complex fluids the vorticity is in general not conserved, due to a mechanism of transfer of energy between different levels.Comment: 12 page