1,954 research outputs found

    Excavations at Tas-Silg, Malta : a preliminary report on the 1996-1998 campaigns conducted by the Department of Classics and Archaeology of the University of Malta

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    The area known as Tas-Silg is situated in the south-eastern part of the island of Malta, close to Marsaxlokk harbour. In reality the place name refers to the small church dedicated to Our Lady of the Snows (hence Tas-Silg) situated at the point where the narrow · road from Zejtun forks out in two directions: to Delimara and Xrobb il-Ghagin due south-east and to Marsaxlokk village due south-west. A British-period fort occupying the highest point of the elongated hill further south along· the first road also carries the same place name. The lower and more compact hill on which the excavations have been conducted is called 'Ta' Berikka' , but since it is so close to the above-mentioned church (only 50 m to the north) the tradition of calling it Tas-Silg is now well established and there is no sense in changing it. The site has a commanding view of the Marsaxlokk harbour to the south and overlooks two other bays, Marsascala and St Thomas's bay, to the north-east. On all sides the slope is broken up by man-made terraced fields There is no doubt that the topography of the site must have been a determining factor in its choice for the establishment of a religious centre in the Temple period of Maltese pehistory (3000--2500 BC), though one must keep in mind that close to Tas-Silg there are three other prehistoric temple sites. each one with a completely different topography. The Temple people were quite introverted in their cultural isolation and do not seem to have been much interested in seafaring and in the outside world. The situation changed radically in the following age, the Bronze Age. when the island was occupied by people who set up villages on naturally defensible hilltops, occasionally fortifying them with artificial ramparts. The Tas-Silg hill with its temple ruins was occupied by these people, but it is not as yet clear for what purpose. The scenario changed again in historical times when the central and western Mediterranean started to be parcelled out among the commercial powers originating in the eastern Mediterranean. The Greeks do not seem to have even tried 10 colonize Malta as they did in neighbouring Sicily. The Phoenicians, however, did occupy the island, apparently through a slow process of peaceful penetration and eventual political and cultural assimi lation. It was in this period that the ruins of the megalithic temple were transformed into a Phoenician extraurban shrine dedicated to Astarte, which in time expanded into a full y-fledged sanctuary with an international reputation. The last chapter in the millennia- long history of the site was written when the colonnaded courtyard in front of the old temple was transformed into an early Christian church. Any use made of the site in the following Arab period is, once again, poorly understood.peer-reviewe

    Optimization and characterization of a microscale thermal field-flow fractionation system

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    Journal ArticleA thorough investigation of the design considerations for microscale thermal field-flow fractionation and characterization of a 25 μm thin microscale thermal field-flow fractionation system is reported. A 4-50 times volume reduction from mesoscale and macroscale systems warrants customized design and operational conditions for microscale separation systems. Theoretical calculations are done to illustrate the importance of the increased dispersion due to extra-column tubing, off-chip detection and sample injection volume with reduced channel dimensions. An optimized microscale thermal field-flow fractionation (ThFFF) channel is fabricated using rapid and cost effective manufacturing and assembly processes. Specifically, improvements in material selection and arrangement are implemented to achieve higher particle retentions. The new instrument arrangement includes high conductivity silicon as the cold wall and a thin polymer layer with low thermal conductivity as the hot wall which results in high temperature gradients (~ 106 ºC/m) across the microchannel and subsequently high retention. Single particle retention separations are carried out with polystyrene nanoparticle samples in an aqueous carrier to characterize the device and demonstrate the improvements

    Glycosylated haemoglobin (HbA1c) and cortisol levels on admission to intensive care as predictors of outcome

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    Objective: To evaluate the predictive value of glycosylated haemoglobin and cortisol on admission, in critical care patients. Design: Prospective, observational, single centre study. Setting: 14 bedded Intensive care unit of a tertiary-level university hospital. Patients: 124 consecutive emergency medical and surgical patients. Methods: Data collected on admission included patient demographics, medical history, medication, diagnosis, type of nutrition, TISS28 score, serum blood glucose, Glycosylated haemoglobin (HbA1c), cortisol, mean arterial blood pressure, and the use of inotropes in the first 24hrs. Daily baseline tests included complete blood count, urea and electrolytes, creatinine, twice weekly liver function tests. The primary outcome measure was intensive care unit mortality. Secondary outcome measures were ITU stay, days of ventilation, peak urea, peak creatinine, lowest platelet count, peak bilirubin, lowest Pa/FiO2, and the number of transfusions. Measurements and results: 124 patients (mean age 56.2 years SD 23.2) were included. Regression analysis was used to identify any potential predictors of outcome: HbA1c levels on admission were not found to be significantly associated with mortality (p=0.51), or any other secondary endpoints listed above. However, subgroup analysis revealed a predictive role of HbA1c with regards to length of ITU stay (p= 0.01) and number of days of ventilation (p=0.007) in those patients with a history of diabetes. Glucose level on admission emerged as an independent marker of mortality (p=0.009). Conclusions: This study suggests that HbA1c may not be a predictor of outcome in the general ITU population but may be of predictive value in diabetic ITU patients. On the other hand, blood glucose levels on admission emerged as a predictor of mortality, whilst no association was found between HbA1c and cortisol levels on admission.peer-reviewe

    Characterization of a microscale thermal-electrical field-flow fractionation system

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    ManuscriptA microscale thermal-electrical field-flow fractionation (ThElFFF) channel is reported for the first time and preliminary characterization results show high retention at certain operating conditions including relatively high flow rates when compared to standard microscale electrical or thermal field-flow fractionation instruments. A new design is presented that simplifies manufacturing and assembly of the prototype and that can provide both an electrical field and a high temperature gradient (~ 106 ?C/m). Monodisperse particle retention is carried out with polystyrene nanoparticle samples to characterize the device. Retention ratios as low as 0.045 are observed with the ThElFFF instrument. Size selectivity of 1.77 was achieved for ThElFFF. The comparison with theory shows a marked deviation from the existing theory. Separation of a mixture of polystyrene particles is demonstrated for first time using a ThElFFF system by separating 130 nm carboxylated polystyrene and 209 nm polystyrene particles

    National Database on Biodiversity : a tool contributing to a better understanding of the flora and fauna of the Maltese Islands

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    The National Database on Biodiversity (NDB) project was initiated in 1991 within the framework of the Biological Diversity and Genetic Resources Network of the Malta Council for Science and Technology (MCST), in partnership with the Department of Biology of the University of Malta. This project is concerned with the collection and cataloguing of information on Maltese biodiversity and with making this information accessible to a wide range of potential users in the form of a computer database. In the pilot and building phases of the project, data on the flora and fauna of the Maltese Islands was structured in an appropriate format and a customised database with data entry, editing, management and querying facilities was created using Corel® Paradox® 8; the database currently holds some 450 species records and can be expanded to cover the entire range of MaItese species. The problems and opportunities in setting up such a database are discussed.peer-reviewe

    Determination of V(V) & Cr(VI) in Presence of Chloride

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    The impact of DM on MHC class II–restricted antigen presentation can be altered by manipulation of MHC–peptide kinetic stability

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    DM edits the peptide repertoire presented by major histocompatibility complex class II molecules by professional antigen-presenting cells (APCs), favoring presentation of some peptides over others. Despite considerable research by many laboratories, there is still significant uncertainty regarding the biochemical attributes of class II–peptide complexes that govern their susceptibility to DM editing. Here, using APCs that either do or do not express DM and a set of unrelated antigens, we found that the intrinsic kinetic stability of class II–peptide complexes is tightly correlated with the effects of DM editing within APCs. Furthermore, through the use of kinetic stability variants of three independent peptides, we demonstrate that increasing or decreasing the kinetic stability of class II–peptide complexes causes a corresponding alteration in DM editing. Finally, we show that the spontaneous kinetic stability of class II complexes correlates directly with the efficiency of presentation by DM+ APCs and the immunodominance of that class II–peptide complex during an immune response. Collectively, these results suggest that the pattern of DM editing in APCs can be intentionally changed by modifying class II–peptide interactions, leading to the desired hierarchy of presentation on APCs, thereby promoting recruitment of CD4 T cells specific for the preferred peptides during an immune response

    Expression Pattern of the Alpha-Kafirin Promoter Coupled with a Signal Peptide from Sorghum bicolor L. Moench

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    Regulatory sequences with endosperm specificity are essential for foreign gene expression in the desired tissue for both grain quality improvement and molecular pharming. In this study, promoters of seed storage α-kafirin genes coupled with signal sequence (ss) were isolated from Sorghum bicolor L. Moench genomic DNA by PCR. The α-kafirin promoter (α-kaf) contains endosperm specificity-determining motifs, prolamin-box, the O2-box 1, CATC, and TATA boxes required for α-kafirin gene expression in sorghum seeds. The constructs pMB-Ubi-gfp and pMB-kaf-gfp were microprojectile bombarded into various sorghum and sweet corn explants. GFP expression was detected on all explants using the Ubi promoter but only in seeds for the α-kaf promoter. This shows that the α-kaf promoter isolated was functional and demonstrated seed-specific GFP expression. The constructs pMB-Ubi-ss-gfp and pMB-kaf-ss-gfp were also bombarded into the same explants. Detection of GFP expression showed that the signal peptide (SP)::GFP fusion can assemble and fold properly, preserving the fluorescent properties of GFP
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