Polyamide 11-Carbon Nanotubes Nanocomposites: Preliminary Investigation

The objective of this research is to develop an improved polyamide 11 (PA11) polymer with enhanced flame retardancy, thermal, and mechanical properties for selective laser sintering (SLS) rapid manufacturing. In the present study, a nanophase was introduced into polyamide 11 via twin screw extrusion. Arkema Rilsan® polyamide 11 molding polymer pellets were used with 1, 3, 5, and 7 wt% loadings of Arkema’s GraphistrengthTM multi-wall carbon nanotubes (MWNTs) to create a family of PA11-MWNT nanocomposites. Transmission electron microscopy and scanning electron microscopy were used to determine the degree and uniformity of dispersion. Injection molded test specimens were fabricated for physical, thermal, mechanical properties, and flammability measurements. Thermal stability of these polyamide 11-MWNT nanocomposites was examined by TGA. Mechanical properties such as ultimate tensile strength, rupture tensile strength, and elongation at rupture were measured. Flammability properties were also obtained using the UL 94 test method. All these different methods and subsequent polymer characteristics are discussed in this paper.Mechanical Engineerin

Relationship between different livestock managements and stress response in dairy ewes

Abstract. The gradual diffusion of intensive and semi-intensive production systems, especially in dairy sheep breeds, has led to the growing concern of consumers about the life conditions of farmed animals. Space allowance and structures of sheep houses are described as the main potential sources of discomfort for housed flocks, together with inappropriate milking procedures and human–animal interactions. The aim of the present study was to evaluate whether the structure relative to milking room could represent a stressor in Sarda dairy ewes. Animals were divided into two groups according to their farm of origin. Group A (n=40) was from a farm whose milking room was an old warehouse with a waiting area limited and located outdoors and at a different level with respect to the milking room. The passageway of the entrance in the milking room was narrow and perpendicular to the milking positioning so the animal must bend 90∘ to enter in the room. Group B (n=40) was from a farm whose milking room was wide and modern with a large waiting area located at the same level. From all animals blood samples were collected at T0 (2h before milking procedure at 06:00), at T1 (immediately after the animals entered the milking room, about 08:00) and at T2 (after milking procedure). In addition plasma cortisol and glucose values were evaluated. Statistical analysis showed significant effect of milking room (P&amp;lt;0.001) and of sampling time (P&amp;lt;0.05) on cortisol and glucose levels. The results obtained in the present study suggest that, in addition to milking, the characteristics of the room where this procedure occurs represent stressful stimuli that could influence negatively the productivity and welfare of dairy ewes.</p

Relationship between different livestock managements and stress response in dairy ewes

The gradual diffusion of intensive and semi-intensive production systems, especially in dairy sheep breeds, has led to the growing concern of consumers about the life conditions of farmed animals. Space allowance and structures of sheep houses are described as the main potential sources of discomfort for housed flocks, together with inappropriate milking procedures and human–animal interactions. The aim of the present study was to evaluate whether the structure relative to milking room could represent a stressor in Sarda dairy ewes. Animals were divided into two groups according to their farm of origin. Group A (n = 40) was from a farm whose milking room was an old warehouse with a waiting area limited and located outdoors and at a different level with respect to the milking room. The passageway of the entrance in the milking room was narrow and perpendicular to the milking positioning so the animal must bend 90° to enter in the room. Group B (n = 40) was from a farm whose milking room was wide and modern with a large waiting area located at the same level. From all animals blood samples were collected at T0 (2 h before milking procedure at 06:00), at T1 (immediately after the animals entered the milking room, about 08:00) and at T2 (after milking procedure). In addition plasma cortisol and glucose values were evaluated. Statistical analysis showed significant effect of milking room (P &lt; 0.001) and of sampling time (P &lt; 0.05) on cortisol and glucose levels. The results obtained in the present study suggest that, in addition to milking, the characteristics of the room where this procedure occurs represent stressful stimuli that could influence negatively the productivity and welfare of dairy ewes

Variable phenotype in 17q12 microdeletions: Clinical and molecular characterization of a new case

Microdeletions of 17q12 including the hepatocyte nuclear factor 1 beta (HNF1B) gene, as well as point mutations of this gene, are associated with the Renal Cysts and Diabetes syndrome (RCAD, OMIM 137920) and genitourinary alterations. Also, microdeletions encompassing HNF1B were identified as a cause of Mayer\u2013Rokitansky\u2013 K\ufcster\u2013Hauser Syndrome (MRKH, OMIM277000) in females and, recently,were associatedwith intellectual disability, autistic features, cerebral anomaly and facial dysmorphisms. In this report, we describe a boywith a deletion in 17q12 region detected by SNP array, encompassing the HNF1B gene, that showed dysmorphic features, intellectual disability (ID), serious speech delay and autistic features. In addition, obesity was observed. In order to study the parental origin of the rearrangement, we analyzed selected SNPs in the deleted area in the patient and his parents, showing Mendelian incompatibilities suggesting a de novo deletion on the chromosome of maternal origin. Our case confirms the incomplete penetrance and variable expressivity of this deletion, its complex clinical variability, and strengthens the evidence that ID and stereotyped behaviors may be part of the phenotypic spectrum characterizing the affected patients. Also, it is useful to further delineate the phenotypes associated to the deletion being the first case in which obesity has been documented. We present a genotype\u2013phenotype correlation discussing the possible role of some genes, encompassed by the deletion, in the etiology of the observed phenotypes

Metabolic and hormonal adaptation in Bubalus bubalis around calving and early lactation

Pregnancy and lactation are physiological periods that result in an increased metabolic demand that, if not satisfied, could provoke a threat to homeostasis. In this study changes in the values of Non-Esterified Fatty Acids (NEFA) and β-hydroxybutyrate (BHB), glucose, insulin, thyroid hormones, milk composition and yield were investigated in buffaloes during the late pregnancy and early lactation. From a total of 50 buffaloes, blood samples were collected -7±5 days before expected calving; +7±5; +30±5 and +50±5 days post-partum; milk samples were collected at the same post-partum time points. On serum samples, the values of Non-Esterified Fatty Acids (NEFA), β-hydroxybutyrate (BHB), glucose, insulin, Triiodothyronine (T3), Thyroxine (T4) and Thyroid-stimulating hormone (TSH) were evaluated. On milk, fat %, protein %, lactose %, somatic cells score (SCS), milk yield and daily milk production (DMP) were assessed. Peripartum period significantly influenced all studied parameters (P<0.05). Milk constituents and productivity statistically changed throughout monitoring period (P<0.005). Milk yield resulted positively correlated with insulin and TSH values, negatively correlated with NEFA and BHB. Insulin was negatively correlated with lactose % and positively correlated with SCS. The obtained results showed that the peripartum period and lactation are accompanied by marked changes in some biochemical variables and in the thyroid hormones values in Italian Mediterranean Buffaloes. Moreover, the relationship found between TSH values and milk yield seems to suggest a possible role of thyroid gland on the maintenance of lactogenesis. This study underlines the importance of monitoring the hormonal status of buffalo during the transition period in order to understand when adjustments of regulatory mechanisms break through physiological limits predisposing the buffalo to metabolic problems

Infinitesimal and local convexity of a hypersurface in a semi-Riemannian manifold

Given a Riemannian manifold M and a hypersurface H in M, it is well known that infinitesimal convexity on a neighborhood of a point in H implies local convexity. We show in this note that the same result holds in a semi-Riemannian manifold. We make some remarks for the case when only timelike, null or spacelike geodesics are involved. The notion of geometric convexity is also reviewed and some applications to geodesic connectedness of an open subset of a Lorentzian manifold are given.Comment: 14 pages, AMSLaTex, 2 figures. v2: typos fixed, added one reference and several comments, statement of last proposition correcte

New mathematical framework for spherical gravitational collapse

A theorem, giving necessary and sufficient condition for naked singularity formation in spherically symmetric non static spacetimes under hypotheses of physical acceptability, is formulated and proved. The theorem relates existence of singular null geodesics to existence of regular curves which are super-solutions of the radial null geodesic equation, and allows us to treat all the known examples of naked singularities from a unified viewpoint. New examples are also found using this approach, and perspectives are discussed.Comment: 8 pages, LaTeX2

Coherence and Consciousness: Study of Fronto-Parietal Gamma Synchrony in Patients with Disorders of Consciousness

Evaluation of consciousness needs to be supported by the evidence of brain activation during external stimulation in patients with unresponsive wakefulness syndrome (UWS). Assessment of patients should include techniques that do not depend on overt motor responses and allow an objective investigation of the spontaneous patterns of brain activity. In particular, electroencephalography (EEG) coherence allows to easily measure functional relationships between pairs of neocortical regions and seems to be closely correlated with cognitive or behavioral measures. Here, we show the contribution of higher order associative cortices of patients with disorder of consciousness (N\ua0=\ua026) in response to simple sensory stimuli, such as visual, auditory and noxious stimulation. In all stimulus modalities an increase of short-range parietal and long-range fronto-parietal coherences in gamma frequencies were seen in the controls and minimally conscious patients. By contrast, UWS patients showed no significant modifications in the EEG patterns after stimulation. Our results suggest that UWS patients can not activate associative cortical networks, suggesting a lack of information integration. In fact, fronto-parietal circuits result to be connectively disrupted, conversely to patients that exhibit some form of consciousness. In the light of this, EEG coherence can be considered a powerful tool to quantify the involvement of cognitive processing giving information about the integrity of fronto-parietal network. This measure can represent a new neurophysiological marker of unconsciousness and help in determining an accurate diagnosis and rehabilitative intervention in each patient