Effect of Weave and Weft Type on Mechanical and Comfort Properties of Hemp-Linen Fabrics.

In this study the influence of fabric weave (plain, twill, and panama) and weft type (flax and hemp yarns) on selected mechanical and comfort properties of six fabrics was analyzed. The results showed that tear and abrasion properties were most affected by the weave. The tensile properties of the linen fabrics were not significantly different when weft hemp yarns were used instead of flax. Fabrics with the same weave seemed to be equally resilient to abrasion regardless of the type of weft. By contrast, the hemp weft yarns favorized the physical and comfort properties of the investigated fabrics. For the same weave, the hemp-linen fabrics were slightly lighter and exhibited lower bulk density, significantly larger air permeability, and improved moisture management properties. Although the results of maximum thermal flux (Qmax) suggested a cooler sensation of the linen fabrics with panama and twill, the hemp-linen fabric with a plain weave seemed to be the optimal choice when a cool sensation was desired. Higher thermal conductivity values also suggested slightly better heat transfer properties of the hemp-linen fabrics, and these were significantly influenced by the weave type. The results clearly indicated the advantages of using hemp for improving physical and specific comfort properties of linen fabrics.

Comparative Analysis of Elastic Polyester Sportswear Fabrics with Printed Graphene Patterns.

In this study two elastic polyester fabrics differentiated by a graphene-printed pattern, called honeycomb (HC) and spider web (SW), were analyzed with a focus on their thermal, mechanical, moisture management and sensorial properties, aiming to identify the fabric with the most elevated heat dissipation and comfort for sportswear. The shape of the graphene-printed circuit did not lead to significant difference between the mechanical properties of the fabrics SW and HC assessed by the Fabric Touch Tester (FTT). Fabric SW outperformed fabric HC with respect of drying time, air permeability, moisture, and liquid management properties. On the other hand, both the Infrared (IR) thermography and FTT-predicted warmness clearly showed that fabric HC dissipates heat faster on its surface along the graphene circuit. This fabric was also predicted by the FTT as smoother and softer than fabric SW and had a better overall fabric hand. The results revealed that both graphene patterns resulted in comfortable fabrics with great potential applications in sportswear fields, in specific use scenario's.

Predicting Compression Pressure of Knitted Fabric Using a Modified Laplace's Law.

The aim of this study is to develop a mathematical model for the prediction of compression pressure based on fabric parameters, such as engineering stress, engineering strain and engineering modulus of elasticity. Four knitted compression fabrics with different fibrous compositions and knit structures were used. Rectangular-cut strips were employed for the force-elongation characterization of the fabrics. The experimental pressure values between the fabric and rigid cylinder were assessed using a Picopress pressure measuring device. The mechanical and physical parameters of the fabric that influence the interface pressure, such as strain, elasticity modulus/stress and thickness, were determined and integrated into Laplace's law. A good correlation was observed between the experimental and calculated pressure values for all combinations of fabrics, mounted with variable tension on the cylinder. Over the considered range of pressures, the difference between the two datasets was generally less than 0.5 mmHg. The effect of washing after five, ten and fifteen washing cycles on the fabric-cylinder interface pressure was found to be significant.

Breathable Textile Rectangular Ring Microstrip Patch Antenna at 2.45 GHz for Wearable Applications.

A textile patch antenna is an attractive package for wearable applications as it offers flexibility, less weight, easy integration into the garment and better comfort to the wearer. When it comes to wearability, above all, comfort comes ahead of the rest of the properties. The air permeability and the water vapor permeability of textiles are linked to the thermophysiological comfort of the wearer as they help to improve the breathability of textiles. This paper includes the construction of a breathable textile rectangular ring microstrip patch antenna with improved water vapor permeability. A selection of high air permeable conductive fabrics and 3-dimensional knitted spacer dielectric substrates was made to ensure better water vapor permeability of the breathable textile rectangular ring microstrip patch antenna. To further improve the water vapor permeability of the breathable textile rectangular ring microstrip patch antenna, a novel approach of inserting a large number of small-sized holes of 1 mm diameter in the conductive layers (the patch and the ground plane) of the antenna was adopted. Besides this, the insertion of a large number of small-sized holes improved the flexibility of the rectangular ring microstrip patch antenna. The result was a breathable perforated (with small-sized holes) textile rectangular ring microstrip patch antenna with the water vapor permeability as high as 5296.70 g/m2 per day, an air permeability as high as 510 mm/s, and with radiation gains being 4.2 dBi and 5.4 dBi in the E-plane and H-plane, respectively. The antenna was designed to resonate for the Industrial, Scientific and Medical band at a specific 2.45 GHz frequency.

Comparative Analysis of Thermophysiological Comfort-Related Properties of Elastic Knitted Fabrics for Cycling Sportswear.

This research focused on the investigation of the thermophysiological comfort properties of four selected knitted fabrics of different fiber blend ratios suitable for cycling wear. Comfort-related properties of the fabrics were determined and compared including air permeability, moisture management properties, drying time, thermal conductivity, and water vapor permeability. For those comfort properties of the fabric to be correlated, fabric structural properties, fabric density, fabric weight, and fabric thickness have been considered. Suited fabrics should have good air permeability, thermal conductivity, moisture management properties, and a short drying time. According to the measurement results, the fabric polyamide/elasane (58/42 PA6.6/EL) with good air permeability, thermal conductivity, moisture management properties, and short drying time was more suited for summer cycling clothing. Furthermore, this paper provides a new understanding of considerations that are needed for several end uses involving specific activity levels.

The echocardiographic assessment of the right ventricle: what to do in 2010?

For many years, the echocardiographic quantitative assessment of right ventricular (RV) function has been difficult owing to the complex RV anatomy. Identifying an accurate and reliable echocardiographic parameter for the functional assessment of the RV still remains a challenge. The review presents a summary of the most studied and presently used parameters of RV function, with their reported normal values, as well as advantages and limitations of use. Combinations of these parameters are used in daily clinical practice, each one offering only partial information about the status of the RV. Myocardial velocity and strain rate imaging have promising results in the assessment of RV function. There is hope that novel myocardial deformation parameters and three-dimensional echocardiography-derived parameters may add value to the examination of the RV, but validation studies are still needed.

[ Study of exo-enzymatic profile and cytotoxic effect of bacterial culture supernatants in different growth phase]. / Studiul profilului exo-enzimatic si al citotoxicitatii supernatantelor de culturi bacteriene în diferite faze de crestere.

Bacterial quorum-sensing represents an ubiquitary regulating system in which the pheromones (small molecules with different chemical structures, i.e. homoserin-lactones, octapeptides, aminoacids) act as extracellular mediators of signaling and intercellular communication. This chemical system is implicated in the regulation of different physiological processes dependent on the cell density (i.e. biolumniscence, virulence factors expression, sporulation, conjugation, antibiotic secretion etc). It is also mentioned in the literature the implication of bacterial pheromones in the modulation of eukariotic cells division rate. The objectives of this study were: a) to determine the exo-enzymatic profile of bacterial cultures in different growth phase in order to establish potential relationships between the phenotypic expression of some virulence factors on one side and the growth phase and bacterial culture density, on the other side; b) to determine de cytotoxic effect and the influence of bacterial culture supernatants on the HEp-2 cell division rate. Supernatants of bacterial cultures in nutrient broth of 2, 5 and 24 hrs of Staphylococcus aureus and Proteus sp. were tested directly and also, after thermic inactivation (at 100 degrees C, for 5 minutes) for the presence of different enzymatic activities known as virulence factors (spot and Kanagawa haemolysins, CAMP-like factor, caseinase, amilase, lipase, lecithinase, mucinase, DNA-ase). The exo-enzymatic profile of bacterial cultures of 2 and 5 hrs proved to be similar, the tested supernatants exhibiting haemolytic activity, and for Staphylococcus aureus, amilase and caseinase activities. Supernatants of and 5 hrs bacterial cultures exhibited also cytotoxic effect on HEp-2 cells. Supernatants of bacterial cultures of 24 hrs exhibited neither enzymatic activities, nor cytotoxic effect on HEp-2 cells, probably due to the inhibition of phenotypic expression of enzymatic activities at high bacterial densities through the activation of the quorum-sensing system. Bacterial supernatants did not significantly influence the HEp-2 cells division rate.