The study and performance of a modified conventional refrigerator to serve as a PV powered one

This paper describes the design and development stages to convert a conventional refrigerator to a solar powered one. The development of such a system was effected and the results of this work to provide a cost effective version are given.A conventional refrigerator was chosen and some changes were introduced to reduce the cooling load and consequently the power required. Tests were carried out to study the performance of the refrigerator components and especially the compressor's, as well as the refrigerator as a whole. The latter tests are the well-known pull down tests.The cost effective final product was searched via a PV sizing package developed for the purpose of this project incorporating the LCC analysis.     

A strange convergence property of the lobatto-chebyshev method for the numerical determination of stress intensity factors

The Lobatto-Chebyshev method for the numerical solution of the Cauchy type singular integral equation of crack problems in two-dimensional elasticity, plates and shells and the determination of the values of the stress intensity factors at the crack tips is shown to converge for non-differentiable Hölder-continuous or even discontinuous loading distributions as far as the values of the stress intensity factors are concerned. Moreover, in all cases of differentiable loading distributions it is shown to converge more rapidly than believed up to now. The problems of a simple straight crack and a periodic array of cracks loaded by three non-differentiable loading distributions are used for the application of the present results. The displayed numerical results for these problems verify and further corroborate the theoretical results. The extension of the present results to the Gauss-Chebyshev method is also quite possible.     

Characterisation of certain major polyphenolic antioxidants in grape (<Emphasis Type="Italic">Vitis vinifera</Emphasis> cv. Roditis) stems by liquid chromatography-mass spectrometry

The stem extract, which was shown to contain high amounts of phenolics and significant antioxidant potency, was further analysed employing liquid chromatography-electrospray ionisation mass spectrometry, in an effort to obtain a deeper insight into its polyphenolic composition. The compounds identified were mainly flavanols (a trimer and a galloylated dimer), flavonols (rutin and quercetin 3-O-glucuronide), stilbenes (trans-resveratrol and a resveratrol dehydrodimer) and a dihydroflavonol glycoside (astilbin).     

Identification of lactic acid bacteria isolated from poultry carcasses by high-resolution melting (HRM) analysis

Lactic acid bacteria (LAB) are a complex group of Gram-positive bacteria belonging to different genera with common morphological, metabolic and physiological characteristics. Their classification was initially based on biochemical methods, but nowadays molecular methods are usually applied for the identification of LAB. Herein, real-time PCR assay coupled with high-resolution melting (HRM) analysis was developed for identifying and distinguishing LAB isolates coming from poultry carcasses. The 16S rRNA gene from these isolates was amplified using primers that annealed to conserved regions. The melting curve analysis of the amplicons classified all isolates into ten LAB species and generated ten distinct HRM curve profiles. The results from HRM analysis were compared to those produced by API 50 CH biochemical microkits and ribosomal DNA sequencing, suggesting the superiority of HRM against API. In conclusion, HRM was proven to be a fast, reliable and cost-effective method for identification of LAB isolates. HRM analysis could be used in order to reduce the time needed for the identification assay and the cost of sequencing the entire group of LAB isolates. The melting profile of known LAB species could be used as a reference for the rapid identification of unknown LAB isolates without the need of sequencing.     

Serum and follicular fluid leptin levels are correlated with human embryo quality

This prospective study was undertaken to reassess the prognostic value of leptin during critical stages of in vitro fertilization-embryo transfer (IVF-ET) and address its role in the functional staging of assisted reproductive technologies at the level of embryo quality. Serum and follicular fluid samples of 100 selected women undergoing the long IVF-ET protocol were collected for leptin and embryo quality determination. The highest serum leptin concentration (52.11 +/- 4.27 ng/ml) was observed on ovum pick up day, while follicular fluid leptin was higher than all serum samples examined (62.59 +/- 5.73 ng/ml). Serum leptin above 59.48 +/- 7.6 ng/ml was associated with 'poor' embryo quality and above 56.87 +/- 5.52 ng/ml with pregnancy failure. Elevated leptin concentrations were associated with reduced ovarian stimulation and response, follicle maturation, embryo quality and pregnancy success. Our findings suggest that leptin modulates embryo quality and may serve as a sensitive marker of IVF outcome.     

Screen-Printing of Cotton with Natural Pigments: Evaluation of Color and Fastness Properties of the Prints

Eleven natural pigments were selected for the production of environment-friendly cotton prints. Physicochemical properties pH, conductivity, viscosity of the printing pastes were measured in order to evaluate their stability and suitability for printing. Quality control standard tests and color measurements were carried out for all the prints with their fastness properties ranging from poor to very good in some cases.     

Estimating the diagnostic accuracy of three culture-dependent methods for the Listeria monocytogenes detection from a Bayesian perspective

The objective of this study was to estimate the test accuracy measures (classification probabilities [CPs], predictive values [PVs], likelihood ratios [LRs] and area under receiving operating characteristic curve [AUC]) of three different culture-dependent methods, commonly used during routine analysis for the detection of the foodborne pathogen Listeria monocytogenes, from a Bayesian perspective. Data from a previous study by Andritsos et al. (2010) were used to define measures of accuracy for the diagnostic tests. Samples of minced pork meat obtained from local markets were tested for L. monocytogenes presence by parallel testing using selective media (PALCAM, ALOA and RAPID'L.mono). Dirichlet distribution, which is the multivariate expression of a Beta distribution, was used to analyze the data. Bayesian analysis determines characteristics of the posterior distribution from available prior information. Results showed that all methods were best at ruling in L. monocytogenes presence than ruling it out. PALCAM seemed to have better performance based on positive PV, positive LR and AUC, but it was not so sensitive as RAPID'L.mono was. Results also showed that none of the media were perfect in detecting L. monocytogenes, i.e. sensitivity and specificity equal to one. Besides, the problem of observing zero counts may be overcome by applying Bayesian analysis, making the determination of a test performance feasible.     

Three-dimensional weft-knitted textile fabrics-based capacitors

Wearable electronics have evolved from electronic components secured on the human body with straps and belts to partial electronic components integration onto textile structures. Cables and standard components defeat the purpose of the wearable approach by being bulky, rigid and especially not being able to withstand standard textile cleaning/care methods (washing, dry-cleaning, etc.). New 3D textile structures can provide a promising solution. In this research project, we examined the capacitive behaviour of specially prepared 3D weft knitted textile fabrics. The samples knitted specially for this project incorporated conductive outer layers and an insulating inner layer. The outer layers form the plates of the capacitor and the insulating layer plays a role of the dielectric material between the two plates. The structure of these 3D knits allows for inherent capacitive behaviour of the material. These 3D weft-knitted fabrics can be produced on usual existing knitting machines, without any need of dedicated, specialized or expensive equipment. The expected values of the capacitance, based on theoretical calculations, satisfactorily approach the values derived from the measuring process. The ability to customize the structure and hence the capacitance of the 3D fabrics-based capacitors is a positive point towards the design of the textile-based electronics systems in the future. Therefore, the development of textile capacitors based on the 3D fabrics is expected to be an essential contribution to the integration of the wearable system concept.     

Probiotic and Technological Properties of Facultatively Heterofermentative Lactobacilli from Greek Traditional Cheeses

Nineteen isolates of facultatively heterofermentative lactobacilli from Feta, Graviera, and Kasseri cheeses were identified by SDS-PAGE of whole-cell proteins as L. paracasei subsp. paracasei (12 strains) and L. plantarum (7 strains) and differentiated at strain level by RAPD-PCR. Properties of technological interest, such as acidification ability, proteolytic activity, and enzyme activities, were also studied. The test strains exhibited a low acidification activity, with significant interstrain differences after growth in milk for 24 h. They were also characterized by different casein breakdown ability, with around 50% of them accumulating amino acids at low amounts in the milk. Lactobacilli isolates differed in respect of enzyme activities, with β-galactosidase being the strongest activity found. Their probiotic potential was evaluated with in vitro studies on the resistance to low pH, bile salts, and pancreatin. The isolates from Feta showed a better survival than those from Kasseri and Graviera at low pH and viable cells were detected even after 3 h at pH 2.0. All strains tolerated bile salts at 0.3% and retained viability in the presence of pancreatin at 0.1%. Different patterns of antibacterial activities were recorded. The strains inhibited preferentially LAB species and some of them clostridia, E. coli O44 and B. cereus. Distinguished strains are promising probiotic candidates as adjuncts and deserve further studies.