Relationship-Specificity, Spatial Clustering and Production to Order Choice

We study the determinants of the firm-level choice to produce following an order placed by a downstream firm (production to order) or to produce in advance. We rationalize this choice through a simple theoretical model and apply it to a firm-level empirical analysis. Relying on a large dataset of Italian manufacturing firms, we show that two main variables affect this choice: the extent of spatial clustering of the industry, and the degree of product complexity and relationship-specificity of the goods that are traded. The sign of the impact of clustering on the choice of producing to order crucially depends on product complexity. If product complexity is high, production to order prevails when firms are clustered together. On the contrary, clustering is associated to production in advance for sectors where goods are standardized.

Technological activities of Staphylococcus carnosus and Staphylococcus simulans strains isolated from fermented sausages

The aim of this study was to determine the technological properties of 2 strains of Staphylococcus simulans (Ssm12, Ssm21) and 4 strains of S. carnosus (SC28, SC31, SC54 and SC55) for the selection of a potential starter cultures to employ in the processing of dry fermented sausages. The strains were studied to evaluate nitrate reductase, proteolytic, lipolytic, decarboxylase and antioxidant activities as well as growth ability at different temperatures, pH and NaCl concentrations. Nitrate reductase activity was determined at 15, 20 and 30 degrees C. By spectrophotometric method all the strains were able to reduce nitrate to nitrite at the different temperatures but these results were not confirmed by the agar plate method. Antioxidant and lipolytic activities were evaluated by spectrophotometric assay. All the strains showed antioxidative enzymes superoxide dismutase (SOD) and catalase whereas all appeared unable to hydrolyse pork fat. Proteolytic activity was determined by agar plate method, spectrophotometric assay (OPA) and sodium dodecyl sulphate gel-electrophoresis (SDS-PAGE) and all strains appeared to be able to hydrolyse sarcoplasmic proteins but not myofibrillar proteins. Finally, all the strains grew at 15 and 20 degrees C, in presence of 10%, 15% and 20% of NaCl and at pH 5.0 and 5.5 and were unable to produce histamine, cadaverine and putrescine. The results showed that all strains studied possess useful technological activities that would make them eligible as a good starter cultures for fermented sausages

Integrating the Ecosystem Services Framework to Define Dysbiosis of the Breastfed Infant Gut: The Role of B. infantis and Human Milk Oligosaccharides

Mounting evidence supports a connection between the composition of the infant gut microbiome and long-term health. In fact, aberrant microbiome compositions during key developmental windows in early life are associated with increased disease risk; therefore, making pertinent modifications to the microbiome during infancy offers significant promise to improve human health. There is growing support for integrating the concept of ecosystem services (the provision of benefits from ecosystems to humans) in linking specific microbiome functions to human well-being. This framework is widely applied in conservation efforts of macro-ecosystems and offers a systematic approach to guide restoration actions aimed to recover critical ecological functions. The aim of this work is to apply the ecosystem services framework to integrate recent studies demonstrating stable alteration of the gut microbiome of breastfed infants when Bifidobacterium longum subsp. infantis EVC001, a gut symbiont capable of efficiently utilizing human milk oligosaccharides into organic acids that are beneficial for the infant and lower intestinal pH, is reintroduced. Additionally, using examples from the literature we illustrate how the absence of B. infantis results in diminished ecosystem services, which may be associated with health consequences related to immune and metabolic disorders. Finally, we propose a model by which infant gut dysbiosis can be defined as a reduction in ecosystem services supplied to the host by the gut microbiome rather than merely changes in diversity or taxonomic composition. Given the increased interest in targeted microbiome modification therapies to decrease acute and chronic disease risk, the model presented here provides a framework to assess the effectiveness of such strategies from a host-centered perspective

Ser dona, un desafiament; ser home, un avantatge

Abstract not availabl

Colonization of breastfed infants by Bifidobacterium longum subsp. infantis EVC001 reduces virulence gene abundance

The infant gut microbiome is rapidly colonized by bacteria from the environment after birth, and this gut ecosystem can facilitate expansion of potential pathogens. Human milk shapes the infant gut microbiome and has evolved to foster the growth of specific bacteria. Breastfed infants fed the coevolved infant gut symbiont Bifidobacterium longum subsp. infantis EVC001 had significant modifications to their gut metagenome, including a decreased number of virulence factor genes

Current distribution in a parallel configuration superconducting strip-line detector

Superconducting detectors based on parallel microscopic strip-lines are promising candidates for single molecule detection in time-of-flight mass spectrometry. The device physics of this configuration is complex. In this letter, we employ nano-optical techniques to study the variation of current density, count rate, and pulse amplitude transversely across the parallel strip device. Using the phenomenological London theory, we are able to correlate our results to a non-uniform current distribution between the strips, governed by the London magnetic penetration depth. This fresh perspective convincingly explains anomalous behaviour in large area parallel superconducting strip-line detectors reported in previous studies

Reduced colonic mucin degradation in breastfed infants colonized by \u3ci\u3eBifidobacterium longum\u3c/i\u3e subsp. \u3ci\u3einfantis\u3c/i\u3e EVC001

Mucin glycoproteins play an important role in protecting the gut epithelium by keeping gut microbes from direct contact with the gut epithelium while allowing for diffusion of small molecules from the lumen to the epithelium. The mucin glycocalyx can be degraded by gut bacteria such as Bacteroides and Akkermansia, but other bacteria, such as Bifidobacterium longum subsp. Infantis, cannot consume mucin glycans. Untargeted mass spectrometry profiles were compared to microbiome profiles to assess how different gut microbiomes affect colonic mucin degradation. Samples obtained from nine infants colonized by Bifidobacterium infantis EVC001 and from 10 infants colonized by higher levels of mucolytic taxa (controls), including Bacteroides, were compared. Previously performed untargeted nano-high-performance liquid chromatography-chip/time-of-flight mass spectrometry was used to detect and quantify glycans originating from colonic mucin. Colonic mucin-derived O-glycans from control infants composed 37.68% (± 3.14% SD) of the total glycan structure pool, whereas colonic mucin-derived O-glycans made up of only 1.78% (± 0.038% SD) of the total in B. infantis EVC001 samples. The relative abundance of these colonic mucin-derived O-glycans in the total glycan pool was higher among control, 26.98% (± 8.48% SD), relative to B. infantis-colonized infants, 1.68% (± 1.12% SD). Key taxa, such as Bacteroidaceae, were significantly and positively correlated with the abundance of these structures, while Bifidobacteriaceae were significantly and negatively associated with these structures. These results suggest that colonization of infants by B. infantis may diminish colonic glycan degradation and help maintain barrier function in the gastrointestinal tract of infants

Control of bulk superconductivity in a BCS superconductor by surface charge doping via electrochemical gating

The electrochemical gating technique is a powerful tool to tune the surface conduction properties of various materials by means of pure charge doping, but its efficiency is thought to be hampered in materials with a good electronic screening. We show that, if applied to a metallic superconductor (NbN thin films), this approach allows observing reversible enhancements or suppressions of the bulk superconducting transition temperature, which vary with the thickness of the films. These results are interpreted in terms of proximity effect, and indicate that the effective screening length depends on the induced charge density, becoming much larger than that predicted by standard screening theory at very high electric fields

Protease and esterase activity of staphylococci

The aim of this work was to characterize protease and esterase activities of staphylococci in order to establish if they could contribute to the release of amino acids and short-chain fatty acids during ripening of fermented sausages. Eighteen Staphylococcus strains belonging to the species Staphylococcus xylosus (5), S. saprophyticus (3), S. equorum (4), S. carnosus (4) and S. simulans (2), previously isolated from different types of Southern Italian fermented sausages, were screened for proteinase, aminopeptidase and esterase activities. Most of the staphylococci strains lacked detectable levels of proteinase activity against casein-fluorescein isothiocynate. In the active strains, this activity was extracellular or cell-envelope associated. The studied staphylococci strains also showed low levels of aminopeptidase activities, which preferentially hydrolysed substrates containing L-methionine, L-leucine and L-phenylalanine as N-terminal residue. In contrast, all staphylococcal strains possessed significant activity against short-chain fatty acid esters. The maximum esterase activities were detected in whole-cell suspensions and cell-free extracts and to a lesser extent in the extracellular medium. The substrates preferentially hydrolysed were ρ-nitrophenyl (ρ-NP) butyrate and ρ-NP caprylate and, secondly, ρ-NP palmitate. The extracellular extracts of most of the strains were only active against ρ-NP butyrate except for those of S. equorum (SI3, SI4) and S. simulans (Ssm12, Ssm21), which also hydrolysed ρ-NP caprylate and ρ-NP palmitate. The cell-free extracts and whole cells were mainly active against ρ-NP butyrate and ρ-NP caprylate, showing activity levels from 1760 U/mg of proteins to 54 U/mg of proteins and from 12,200 U/mg of proteins to 133 U/mg of proteins respectively. These activities were especially high in the strains that belonged to S. xylosus and S. equorum species. The diversity of the studied metabolic properties and, especially, the esterase activities in different staphylococcal species and even strains of the same species emphasize the relevance of these in vitro characterization studies for a rational selection of new starter cultures

Reproducibility of NIRS Assessment of Muscle Oxidative Capacity in Smokers With and Without COPD

Low muscle oxidative capacity contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). Near-infrared spectroscopy (NIRS) allows non-invasive determination of the muscle oxygen consumption (mV̇O2) recovery rate constant (k), which is proportional to oxidative capacity assuming two conditions are met: 1) exercise intensity is sufficient to fully-activate mitochondrial oxidative enzymes; 2) sufficient O2 availability. We aimed to determine reproducibility (coefficient of variation, CV; intraclass correlation coefficient, ICC) of NIRS k assessment in the gastrocnemius of 64 participants with (FEV1 64 ± 23%predicted) or without COPD (FEV1 98 ± 14%predicted). 10–15 s dynamic contractions preceded 6 min of intermittent arterial occlusions (5–10 s each, ∼250 mmHg) for k measurement. k was lower (P < 0.05) in COPD (1.43 ± 0.4 min−1; CV = 9.8 ± 5.9%, ICC = 0.88) than controls (1.74 ± 0.69 min−1; CV = 9.9 ± 8.4%; ICC = 0.93). Poor k reproducibility was more common when post-contraction mV̇O2 and deoxygenation were low, suggesting insufficient exercise intensity for mitochondrial activation and/or the NIRS signal contained little light reflected from active muscle. The NIRS assessment was well tolerated and reproducible for muscle dysfunction evaluation in COPD