The medicinal use of leeches in Malta

The medical practice based on the Greek doctrine of the four humors considered that disease was due to alterations in the composition of these humors, and therapy was therefore based on attempting to restore the balance. Bleeding was the first resort in the treatment of a large majority of diseases ­ a therapeutic measure that persisted throughout the centuries. Bloodletting generally took the form of using a knife or lancet to open a vein, a procedure referred to as venesection or phlebotomy. A gentler and more desirable form of bleeding was to put a leech on the affected part and to let the animal engorge itself with the bad blood thought to dwell below the point of application. Leeches have been used medically for centuries; in Europe the use of leeches to drain off blood reached its height of popularity in the 19th century. The practice of bloodletting in the Maltese Islands dates at least to about the 2nd century AD. A tomb-slab from the late Roman/Palaeo-Christian period depicts a set of surgical instruments that include two Roman cupping vessels 1. Only 93 kilometers away from Sicily and 290 km from Northern Africa, the Maltese archipelago with its central position in the Mediterranean was an important meeting place for the various cultures that dominated the region. Malta's location at the crossroads of culture is reflected by the medical practices in use throughout the centuries. The practice of venesection in Malta persisted through the ages and during the medieval period (1539), the procedure was being carried out by the barbersurgeons against payment of one unza2. The barber-surgeons or barberotti remained responsible for venesection well into the 19th century and were only removed from the list of medical practitioners in 19213. The gentler form of bloodletting through the use of leeches was also practiced in Malta.peer-reviewe

Microstructural Evolution and Mechanical Property Development of Selective Laser Melted Copper Alloys

Selective Laser Melting (SLM) is an additive manufacturing technology that utilizes a high-power laser to melt metal powder and form a part layer-by-layer. Over the last 25 years, the technology has progressed from prototyping polymer parts to full scale production of metal component. SLM offers several advantages over traditional manufacturing techniques; however, the current alloy systems that are researched and utilized for SLM do not address applications requiring high electrical and thermal conductivity. This work presents a characterization of the microstructural evolution and mechanical property development of two copper alloys fabricated via SLM and post-process heat treated to address this gap in knowledge. Tensile testing, conductivity measurement, and detailed microstructural characterization was carried out on samples in the as-printed and heat treated conditions.A single phase solid solution strengthened binary alloy, Cu-4.3Sn, was the first alloy studied. Components were selectively laser melted from pre-alloyed Cu-4.3Sn powder and heat treated at 873 K (600 °C) and 1173 K (900 °C) for 1 hour. As-printed samples were around 97 percent dense with a yield strength of 274 MPa, an electrical conductivity of 24.1 %IACS, and an elongation of 5.6%. Heat treatment resulted in lower yield strength with significant increases in ductility due to recrystallization and a decrease in dislocation density. Tensile sample geometry and surface finish also showed a significant effect on measured yield strength but a negligible change in measured ductility. Microstructural characterization indicated that grains primarily grow epitaxially with a sub-micron cellular solidification sub-structure. Nanometer scale tin dioxide particles identified via XRD were found throughout the structure in the tin-rich intercellular regions.The second alloy studied was a high-performance precipitation hardening Cu-Ni-Si alloy, C70250. Pre-alloyed powder was selectively laser melted to produce components around 98 percent dense with high mechanical strength and electrical conductivity. Aging heat treatments were carried out at 723 K (450 °C) directly on as-printed samples up to 128 hours. A peak yield strength of around 590 MPa could be attained with an electrical conductivity of 34.2 %IACS after 8 hours of aging. Conductivity continues to increase with further aging while the peak strength appears to be less sensitive to aging time exhibiting a broad range of time where near-peak properties exist. Nanometer-scale silicon-rich oxide particles exist throughout the material and persist during aging. Deformation twinning is observed in the peak age condition after tensile testing and several strengthening mechanisms appear to be active to varying degrees throughout aging, which accounts for the broad range of aging time where nearly the peak mechanical properties exist. The findings of this research are integral to understanding SLM copper alloys and serve as a foundation for future development of new copper alloys tailored to the SLM process

Anodic Aluminum Oxide (AAO) Membranes for Cellular Devices

Anodic Aluminum Oxide (AAO) membranes can be fabricated with a highly tunable pore structure making them a suitable candidate for cellular hybrid devices with single-molecule selectivity. The objective of this study was to characterize the cellular response of AAO membranes with varying pore sizes to serve as a proof-of-concept for an artificial material/cell synapse system. AAO membranes with pore diameters ranging from 34-117 nm were achieved via anodization at a temperature of -1̊C in a 2.7% oxalic acid electrolyte. An operating window was established for this setup to create membranes with through-pore and disordered pore morphologies. C17.2 neural stem cells were seeded onto the membranes and differentiated via serum withdrawal. The data suggests a highly tunable correlation between AAO pore diameter and differentiated cell populations. Analysis of membranes before and after cell culture indicated no breakdown of the through-pore structure. Immunocytochemistry (ICC) showed that AAO membranes had increased neurite outgrowth when compared to tissue culture treated (TCT) glass, and neurite outgrowth varied with pore diameter. Additionally, lower neuronal percentages were found on AAO as compared to TCT glass; however, neuronal population was also found to vary with pore diameter. Scanning electron microscopy (SEM) and ICC images suggested the presence of a tissue-like layer with a mixed-phenotype population. AAO membranes appear to be an excellent candidate for cellular devices, but more work must be completed to understand the surface chemistry of the AAO membranes as it relates to cellular response

Maltese national birth weight for gestational age centile values

The relevance of using literature derived birth weight for gestational age centile charts for the Maltese population is debatable. The study set out to develop national weight for gestational age centile charts and compare these to other populations. Method: Anonymised birth weight for gestational age data with relevant maternal and neonatal observations over the period 1995-2009 were obtained from national statistics. The formats were standardised and imported into an SQL database that enabled filtration for single live births and grouping by sex. The data was scrutinized manually for obvious keying errors. The best estimate of gestational age from the last menstrual period (LMP) and expected date of delivery (EDD) was selected using established guidelines. A Box-Cox gamma transform was used to fit the model and generate separate centile charts. The data was compared to previous birth weight data reported in Maltese newborns in previous decades and to data from other countries. Results: A total of 58,899 neonates were included in the study and birth weight for gestational age centile charts were generated between 23 and 42 weeks of gestation using Revolution R with VGAM. There has been a statistically significant gradual fall in mean birth weight in Maltese newborns over the last four decades. There are also statistically significant differences between the Maltese data and those from other countries. Conclusion: The observed differences make the use of national birth weight for gestational age centile charts desirable both for routine clinical assessment and epidemiological studies.peer-reviewe

Medicinal and other leeches (Annelida, Hirudinea) in the Maltese Islands

The identity and possible provenance of the leeches used medicinally in the Maltese Islands since the sixteenth century and particularly during the nineteenth century is discussed. Two haematophagous species have been identified as possible medicinal imports. Five other non-medicinal species of leeches have been identified as either presently occurring in the Maltese Islands, or as having been possibly introduced in the past.peer-reviewe

The CFHT Open Star Cluster Survey II -- Deep CCD Photometry of the Old Open Star Cluster NGC 6819

We present analysis of deep CCD photometry for the very rich, old open star cluster NGC 6819. These CFH12K data results represent the first of nineteen open star clusters which were imaged as a part of the CFHT Open Star Cluster Survey. We find a tight, very rich, main-sequence and turn-off consisting of over 2900 cluster stars in the V, B-V color-magnitude diagram (CMD). Main-sequence fitting of the un-evolved cluster stars with the Hyades star cluster yields a distance modulus of (m-M)v = 12.30 +/- 0.12, for a reddening of E(B-V) = 0.10. These values are consistent with a newly calculated theoretical stellar isochrone of age 2.5 Gyrs, which we take to be the age of the cluster. Detailed star counts indicate a much larger cluster extent (R = 9.5' +/- 1.0'), by a factor of ~2 over some previous estimates. Incompleteness tests confirm a slightly negatively sloped luminosity function extending to faint (V ~ 23) magnitudes which is indicative of a dynamically evolved cluster. Further luminosity function and mass segregation tests indicate that low mass objects (M < 0.65Mo) predominate in the outer regions of the cluster, 3.5 < R < 9.5. The estimation of the number of white dwarfs in NGC 6819 are in good agreement with the observed number. For those white dwarf candidates which pass both a statistical and image classification tests, we show comparisons to white dwarf isochrones and cooling models which suggest the need for spectroscopy to confirm the white dwarf nature of the brighter objects.Comment: 15 Figures and 6 Tables available in higher resolution from ADS. Accepted for Publication in AJ -- Kalirai et al. 2001b, 122, 266. Update

Clinical characteristics, treatment patterns and outcomes of Hispanic hypertensive patients

Hispanics are the largest and fastest-growing minority population in the United States, currently comprising about 16.3% (52 million) of the total population. With an increased prevalence of metabolic risk factors in this population, the rate of uncontrolled hypertension (HTN) in Hispanics significantly exceeds the rates observed among non-Hispanic blacks and whites. Unfortunately, data on HTN in Hispanics remains limited due to the under-representation of Hispanics in clinical trials; with most of the data primarily restricted to observational and retrospective subgroup analyses. This article aims to review the available data on prevalence, awareness and control of HTN, risk factors and some of the challenges unique to the Hispanics population. We also discuss treatment strategies derived from large HTN trials that included Hispanics

Models for Pop I stars: implications for age determinations

Starting from a few topical astrophysical questions which require the knowledge of the age of Pop I stars, we discuss the needed precision on the age in order to make progresses in these areas of research. Then we review the effects of various inputs of the stellar models on the age determination and try to identify those affecting the most the lifetimes of stars.Comment: 10 pages, 6 figures, 2 tables, IAU Symp. 258, D. Soderblom et al. ed