Short Communication: Improvements to INRIM Johnson Noise Thermometer

This paper presents a progress report for the Johnson noise thermometry experiment which is under development at the Istituto Nazionale di Ricerca Metrologica. In order to aim at an uncertainty level better than 10⁻⁵ and to reduce the measurement time, a new setup has been developed. In particular, several modifications have been applied to the experiment described by Callegaro et al. (Metrologia 46: 409, 2009) to improve the traceability to voltage, resistance and frequency standards, and new amplifiers have been designed in order to expand the working frequency range up to 20 kHz, with a sensing resistor of 1 kΩ, while maintaining amplifier induced systematic errors to an acceptable level.     

Electrodeposition of Cu–Zn alloy coatings from citrate baths containing benzotriazole and cysteine as additives

Alternative electrolytes, such as citrate baths, are now studied, aiming to reduce the toxicity and the cost of the electroplating process while maintaining the decorative qualities and anticorrosive properties of the coatings. For this purpose, brightening and/or leveling compounds are usually added to the base citrate bath. In this work, Cu–Zn alloys were electroplated on mild steel substrates from electrolytes containing sodium citrate and additives (benzotriazole and cysteine) at constant stirring speed. The results showed that coatings produced from baths containing additives were brighter than those obtained from the base citrate bath. Additionally, the presence of benzotriazole directly influenced the coating composition and the properties of the deposited alloy: the amount of zinc in this coating increased excessively, and the coating/substrate corrosion presented a poor anticorrosive performance.     

Fatty acids profile of oil from nine varieties of Macadamia nut

The fatty acids profile and lipids content of the Macadamia integrifolia and Macadamia tetraphylla varieties and interspecies hybrids, M. integrifolia and M. tetraphylla were analyzed. Total lipids content ranged from 70.9 to 79.7 g of oil per 100 g^?1 dry-solids. Gas chromatography/mass spectrophotometry identified 20 fatty acids, the most abundant of which were oleic acid (40 to 51%), palmitoleic acid (24 to 36%), and palmitic acid (8.4 to 13.1%). Fatty acids concentration differed between varieties and hybrids (Multivariate analysis of variance, F = 13.89, p < 0.0001). A ratio of monounsaturated fatty acids:saturated fatty acid values ranged from 2.8 to 4.6. The Huatusco variety (M. integrifolia and M. tetraphylla) exhibited the highest percentage of lipids (79.7 g of oil per 100 g^?1 DS) and the highest monounsaturated fatty acids:saturated fatty acid (4.6), thus highlighted its potential applications within the food industry. The Cate variety (M. integrifolia and M. tetraphylla) had the lowest monounsaturated fatty acids:saturated fatty acid, suggesting potential uses in the cosmetics industry.     

Evaluation of vehicle side airbag effectiveness in Victoria,Australia

Side airbag systems were first introduced into vehicles around 1995 to help protect occupants from injury in side impact crashes. International studies have shown that side airbags are effective in reducing the risk of death and injury, however, serious injuries can still occur even when side airbags deploy. The objective of this study was to use detailed injury information from insurance injury compensation claims data linked to Police reported crash data to determine the effectiveness of side airbags in reducing the risk of death or injury for occupants involved in side impact crashes in Victoria, Australia based on the specific body regions that side airbag systems are designed to protect. It was found that head and torso-protecting dual airbag systems designed to protect the head, neck, face, chest and abdomen are highly effective in reducing driver death or injury due to near side crashes. They were associated with a statistically significant reduction of 41.1% (25.9%, 53.2%) in the odds of death or injury across all body regions; and a 48.0% (28.0%, 62.4%) reduction in the odds of death or injury to the head, neck, face, chest and abdomen. The study did not find any evidence that torso-protecting airbags alone are effective in reducing death or injury. Analysis results indicate that head and torso-protecting side airbag systems in vehicles are a highly effective technology for reducing the risk of death or injury to vehicle occupants in near side crashes. The magnitude of the injury reduction benefits estimated indicate that fitment of this technology to all vehicles should be a high priority and will yield significant savings in overall road trauma.     

Design and Performance of a High-Efficiency Commercial

A gas-fired commercial water heater has been developed which achieves a steady-state efficiency of over 95 percent and can obtain overall service efficiencies above 90 percent in many applications. These high levels of efficiency are obtained by operating in the condensing mode over a substantial portion of the duty cycle. The use of a power burner and a coil-type heat exchanger results in a compact configuration which produces both high efficiency and low emissions. The design, operating principles, and performance characteristics of the water heater are described.     

Dependability issues in visual–haptic interfaces

Dependability of a system is commonly referred to its reliability, its availability and its maintenability (RAM), but when this concept is applied to user interfaces there is no common agreement on what aspects of user–system interaction are related to a satisfactory RAM level for the whole system. In particular, when dealing with haptic systems, interface dependability may become a crucial issue in medical and in military domains when life-critical systems are to be manipulated or where costly remote control operations are to be performed, like in industrial processes control or in aerospace/automotive engineering and manufacturing. This paper discusses the role of dependability in haptic user interfaces, aiming to the definition of a framework for the assessment of the usability and dependability properties of haptic systems and their possible correlations. The research is based on the analysis of a visual–haptic-based simulator targeted to maintenance activity training for aerospace industry which is taken as a case study. As a result, we propose a novel framework able to collect and then process relevant interaction data during the execution of haptic tasks, enabling to analyze dependability vs. usability correlations.     

Stabilization of linear systems with limited information

We show that the coarsest, or least dense, quantizer that quadratically stabilizes a single input linear discrete time invariant system is logarithmic, and can be computed by solving a special linear quadratic regulator problem. We provide a closed form for the optimal logarithmic base exclusively in terms of the unstable eigenvalues of the system. We show how to design quantized state-feedback controllers, and quantized state estimators. This leads to the design of hybrid output feedback controllers. The theory is then extended to sampling and quantization of continuous time linear systems sampled at constant time intervals. We generalize the definition of density of quantization to the density of sampling and quantization in a natural way, and search for the coarsest sampling and quantization scheme that ensures stability. Finally, by relaxing the definition of quadratic stability, we show how to construct logarithmic quantizers with only finite number of quantization levels and still achieve practical stability of the closed-loop system     

A New Human Platelet Lysate for Mesenchymal Stem Cell Production Compliant with Good Manufacturing Practice Conditions Preserves the Chemical Characteristics and Biological Activity of Lyo-Secretome Isolated by Ultrafiltration

Recently, we proposed a Good Manufacturing Practice (GMP)-compliant production process for freeze-dried mesenchymal stem cell (MSC)-secretome (lyo-secretome): after serum starvation, the cell supernatant was collected, and the secretome was concentrated by ultrafiltration and freeze-dried, obtaining a standardized ready-to-use and stable powder. In this work, we modified the type of human platelet lysate (HPL) used as an MSC culture supplement during the lyo-secretome production process: the aim was to verify whether this change had an impact on product quality and also whether this new procedure could be validated according to GMP, proving the process robustness. MSCs were cultured with two HPLs: the standard previously validated one (HPL-E) and the new one (HPL-S). From the same pool of platelets, two batches of HPL were obtained: HPL-E (by repeated freezing and thawing cycles) and HPL-S (by adding Ca-gluconate to form a clot and its subsequent mechanical wringing). Bone marrow MSCs from three donors were separately cultured with the two HPLs until the third passage and then employed to produce lyo-secretome. The following indicators were selected to evaluate the process performance: (i) the lyo-secretome quantitative composition (in lipids and proteins), (ii) the EVs size distribution, and (iii) anti-elastase and (iv) immunomodulant activity as potency tests. The new HPL supplementation for MSCs culture induced only a few minimal changes in protein/lipid content and EVs size distribution; despite this, it did not significantly influence biological activity. The donor intrinsic MSCs variability in secretome secretion instead strongly affected the quality of the finished product and could be mitigated by concentrating the final product to reach a determined protein (and lipid) concentration. In conclusion, the modification of the type of HPL in the MSCs culture during lyo-secretome production induces only minimal changes in the composition but not in the potency, and therefore, the new procedure can be validated according to GMP.     

Engineering stability into Escherichia coli secreted Fabs leads to increased functional expression

The recombinant expression of immunoglobulin domains, Fabs and scFvs in particular, in Escherichia coli can vary significantly from antibody to antibody. We hypothesized that poor Fab expression is often linked to poor intrinsic stability. To investigate this further, we applied a novel approach for stabilizing a poorly expressing anti-tetanus toxoid human Fab with a predisposition for being misfolded and non-functional. Forty-five residues within the Fab were chosen for saturation mutagenesis based on residue frequency analysis and positional entropy calculations. Using automated screening, we determined the approximate midpoint temperature of thermal denaturation (TM) for over 4000 library members with a maximum theoretical diversity of 855 unique mutations. This dataset led to the identification of 11 residue positions, primarily in the Fv region, which when mutated enhanced Fab stability. By combining these mutations, the TM of the Fab was increased to 92 degrees C. Increases in Fab stability correlated with higher expressed Fab yields and higher levels of properly folded and functional protein. The mutations were selected based on their ability to increase the apparent stability of the Fab and therefore the exact mechanism behind the enhanced expression in E.coli remains undefined. The wild-type and two optimized Fabs were converted to an IgG1 format and expressed in mammalian cells. The optimized IgG1 molecules demonstrated identical gains in thermostability compared to the Fabs; however, the expression levels were unaffected suggesting that the eukaryotic secretion system is capable of correcting potential folding issues prevalent in E.coli. Overall, the results have significant implications for the bacterial expression of functional antibody domains as well as for the production of stable, high affinity therapeutic antibodies in mammalian cells.     

Myoclonic absence-like seizures and chromosome abnormality syndromes

PURPOSE: We explored the relationship between myoclonic absence seizures (MAS) and underlying chromosome disorders. METHODS: Among 14 patients with MAS observed in three centers, 5 had typical cryptogenic myoclonic absence epilepsy (MAE), 2 had MAS associated with other seizure types (1 with signs of a neuronal migration abnormality and 1 with signs of a metabolic disorder), and 7 had MAS, with or without other seizure types, complicating a chromosome abnormality syndrome-2 with trisomy 12p, 4 with Angelman syndrome, and 1 with inv dup (15). RESULTS: In the 7 patients with chromosomopathy, MAS appeared at a mean age of 2.9 years (range 4 months to 6 years 6 months), had a duration of 4-20 s, and were accompanied by reduced awareness and rhythmic myoclonic jerks involving proximal limb muscles. Ictal EEG showed 2- to 3-Hz generalized spike-and-wave discharges. CONCLUSIONS: In these patients, MAS differed slightly from those of typical MAE: age of onset was earlier, absences were of shorter duration, and no clear increase in muscular tone was noted. Abnormal expression of genes codifying for the subfamily of K+ channels and for gamma-aminobutyric acid-3 subunit receptors (GABRB3), both located in the chromosome segments involved in the chromosomopathies presented by our patients, could be responsible for the same generalized seizure type. Chromosome analysis should be performed in patients with mental retardation and MAS, especially when the ictal pattern does not completely overlap that observed in MAE.