375 research outputs found

    PtSi Clustering In Silicon Probed by Transport Spectroscopy

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    Metal silicides formed by means of thermal annealing processes are employed as contact materials in microelectronics. Control of the structure of silicide/silicon interfaces becomes a critical issue when the device characteristic size is reduced below a few tens of nanometers. Here we report on silicide clustering occurring within the channel of PtSi/Si/PtSi Schottky barrier transistors. This phenomenon is investigated through atomistic simulations and low-temperature resonant tunneling spectroscopy. Our results provide evidence for the segregation of a PtSi cluster with a diameter of a few nanometers from the silicide contact. The cluster acts as metallic quantum dot giving rise to distinct signatures of quantum transport through its discrete energy states

    Quantifying the relevance of different mediators in the human immune cell network

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    Immune cells coordinate their efforts for the correct and efficient functioning of the immune system (IS). Each cell type plays a distinct role and communicates with other cell types through mediators such as cytokines, chemokines and hormones, among others, that are crucial for the functioning of the IS and its fine tuning. Nevertheless, a quantitative analysis of the topological properties of an immunological network involving this complex interchange of mediators among immune cells is still lacking. Here we present a method for quantifying the relevance of different mediators in the immune network, which exploits a definition of centrality based on the concept of efficient communication. The analysis, applied to the human immune system, indicates that its mediators significantly differ in their network relevance. We found that cytokines involved in innate immunity and inflammation and some hormones rank highest in the network, revealing that the most prominent mediators of the IS are molecules involved in these ancestral types of defence mechanisms highly integrated with the adaptive immune response, and at the interplay among the nervous, the endocrine and the immune systems.Comment: 10 pages, 3 figure

    Influence of milk somatic cell content on Parmigiano-Reggiano cheese yield

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    The aim of this study was to determine the influence of the somatic cell content (SCC) of milk on Parmigiano-Reggiano cheese yield, produced in commercial cheese factories under field conditions. The study was carried out following the production of 56 batches of Parmigiano-Reggiano in 13 commercial cheese factories by processing milk collected from Italian Friesian cattle herds. The vat-milk (V-milk) used for making each cheese batch was obtained by mixing evening milk (partially skimmed following spontaneous separation of fat overnight, natural creaming) and morning milk. The batches of cheese produced were divided into 5 classes according to the SCC value of the evening milk determined prior to natural creaming (class 1, from 0 to 200 000; 2, 201 000-300 000; 3, 301 000-400 000; 4, 401 000-500 000; 5, over 501 000 cells/ml). The cheese yield was calculated as the amount of 24-h cheese, expressed in kilograms, obtained from 100 kg of V-milk (24 h ACY). The values of fat, crude protein, true protein, casein and 24 h ACY of V-milk were negatively correlated with the somatic cell score (SCS) of the evening milk. Conversely, a positive correlation was observed between chloride and SCS. Fat, protein fractions (crude protein, casein and whey proteins), P and titratable acidity of V-milk were positively correlated with its 24 h ACY, while chloride, pH and SCS showed a negative correlation. A significant drop in 24 h ACY was observed in classes 3, 4 and 5, therefore when the SCC of the evening milk exceeded 300 000 cells/ml. Finally a lower recovery of milk fat in cheese was observed as SCC of evening milk increase

    Effects of Milk Storage Temperature at the Farm on the Characteristics of Parmigiano Reggiano Cheese: Chemical Composition and Proteolysis

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    Parmigiano Reggiano is a Protected Designation of Origin (PDO) cheese whose official production protocol provides that milk cannot be stored at less than 18 °C at the farm. The possibility of refrigerating milk at the farm is highly debated, since it should allow for the limiting of bacterial growth, thus improving the quality of the cheese. The present research aimed to study the influence of storing the milk at 9 °C on the chemical composition and proteolysis during the ripening of Parmigiano Reggiano cheese. The experimentation considered six cheese-making trials, in which both evening and morning milks were subdivided into two parts that were maintained at 9 and 20 °C. After Parmigiano Reggiano cheese-making, one of the twin wheels obtained was analyzed after 21 months of ripening. From each cheese, two different samples were taken, one from the inner zone, and the other from the outer zone. The results of the chemical analyses evidenced that milk storage at 9 °C significantly (p ≤ 0.05) influenced fat, crude protein, soluble nitrogen and peptone nitrogen contents. Nevertheless, the differences observed with respect to the cheese obtained with milk stored under standard condition were very small and should be considered within the “normal variations” of Parmigiano Reggiano chemical characteristics

    Effects of somatic cell count on the gross composition, protein fractions and mineral content of individual ewe’s milk

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    The aim of the research was to evaluate the effect of two somatic cell content (SCC) levels (<265,000 and >265,000 cells/ml) on ewe milk composition, protein fractions and mineral content. Samples were collected during two years, from three different ewe herds. Each herd was surveyed four times per year, one per season. For each survey more than 10 individual milk samples were collected during morning milking and analysed for SCC. On the basis of the results, two individual milk samples were selected: one from a sheep with low milk SCC (up to 265.000 cells/mL; LCC) and one from a sheep with high milk SCC (over 265,000 and less than 1,000,000 cells/mL; HCC). In one herd, it was not possible to collect the milk samples in summer. So, a total of 44 ewe milk samples (22 comparative pairs) were collected. On each milk sample, crude protein, crude whey protein, casein, casein number, non protein nitrogen x 6.38, true protein, true whey protein, fat, lactose, dry matter, ash, phosphorus, calcium, magnesium and chloride were determined. Average SCC in LCC was 170,000 and 466,000 cells/ml in HCC milk. HCC milk had lower lactose (4.05 vs. 4.60 g/100 g), casein (3.91 vs. 4.28 g/100 g), phosphorus (131.31 vs. 138.81 mg/100 g), calcium (157.28 vs. 170.48 mg/100 g) and magnesium (14.59 vs. 15.30 mg/100 g) contents than LCC milk. Additionally, HCC milk had lower casein number (76.53 vs. 79.03%) and higher contents of true whey protein (1.00 vs. 0.92 g/100 g), ash (0.90 vs. 0.87 g/100 g) and chloride (103.57 vs. 93.17 mg/100 g) than LCC milk. Somatic cell content significantly affected ewe milk quality. As a result of the higher lactose, casein, phosphorus, calcium and magnesium contents, LCC milk was more suitable for cheese making than HCC milk.Key words: Ewe milk, milk quality, chemical composition, somatic cell content

    The Mediating Role of Romantic Attachment in the Relationship Between Attachment to Parents and Aggression

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    Background: A secure attachment style could promote more intimacy in romantic relationships, while an insecure attachment style could be correlated with less positive romantic relationships in adulthood. Numerous studies have noted that a secure attachment to parents was correlated with lower levels of aggression, whereas insecure attachments were associated with higher levels of aggression. We aimed to investigate the role of the attachment system as a mediator of the expression of aggressiveness during adolescence. Specifically, we considered that the attachment to parents and peers could influence one's attachment to a romantic partner.Methods: We empirically tested whether there were relationships of parent and peer attachment on aggressiveness mediated by romantic attachment style. Participants of the study included 411 students.Results: Results indicated that for males an insecure father-child attachment style seems to be associated with higher levels of anxiety and avoidance in romantic attachments and then with aggressiveness. For females, an insecure mother-child attachment style seems to be associated with higher levels of aggressiveness.Conclusion: The attachment to parents and to peers plays a key role in defining romantic attachment according to gender, and these dimensions in turn tend to affect the levels of aggressiveness

    Evaluating Semantic Knowledge Through a Semantic Association Task in Individuals With Dementia

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    Conceptual knowledge is supported by multiple semantic systems that are specialized for the analysis of different properties associated with object concepts. Various types of semantic association between concrete concepts—categorical (CA), encyclopedic (EA), functional (FA), and visual-encyclopedic (VEA) associations—were tested through a new picture-to-picture matching task (semantic association task, SAT). Forty individuals with Alzheimer's disease (AD), 13 with behavioral variant of frontotemporal dementia (bv-FTD), 6 with primary progressive aphasia (PPA), and 37 healthy participants were tested with the SAT. Within-group comparisons highlighted a global impairment of all types of semantic association in bv-FTD individuals but a disproportionate impairment of EA and FA, with relative sparing of CA and VEA, in AD individuals. Single-case analyses detected dissociations in all dementia groups. Conceptual knowledge can be selectively impaired in various types of neurodegenerative disease on the basis of the specific cognitive process that is disrupted

    Influence of feeding flavouring-appetizing substances on activity of cows in an automatic milking system

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    Aim of this research was to study the effect of somatic cell count on mineral content and salt equilibria at the level of quarter milk samples. Ten Italian Friesian cows, in which two homologous quarters (front quarters in 1 cow, rear quarters in 6 cows and both rear and front quarters in 3 cows) were characterised by a milk SCC400,000 cells/mL (HC-milk), respectively, were selected. Cows were milked at quarter level during the morning milking and a single sample was collected from each selected quarter, thus, 26 quarter milk samples were collected. Compared to LC-milk, HC-milk was characterised by a lower content of phosphorus and potassium and by a higher content of both sodium and chloride. The equilibrium of calcium, phosphorus and magnesium between the colloidal and soluble phase of milk and the mineralisation degree of the casein micelles, were not different between HC and LC milk

    New insights into the quality characteristics of milk from Modenese breed compared with Italian Friesian

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    This study examined the milk quality of the autochthonous cattle breed Modenese (MO) in comparison with Italian Friesian (IF), at peak and mid lactation, with the aim to support the interest in sustainability of the local cattle breeds in Europe. Forty-eight individual milk samples were collected from 11 MO and 14 IF pluriparous cows, housed in a free stall barn under similar conditions of feeding and management, at 8 and 21 weeks post-calving; daily milk yield (MY) and body condition score (BCS) were individually recorded. Breed differences were observed, being MY lower in MO cows, but BCS, titratable acidity, freezing point, casein (MC), total calcium (Ca), total phosphorus (P) and colloidal P contents were higher compared to IF cows. Time affected BCS, MY, milk protein (MP), MC, urea, casein P and the micellar content of colloidal Ca and colloidal inorganic P. A factorial analysis was performed and four common factors were obtained with a cumulative explained variance of 77.7% of the total original. MO milk showed a nutritionally interesting mineral profile and processing properties suitable for the production of typical cheese that could be interesting for improving the interest in the conservation of animal genetic resources
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