The effect of boron incorporation on the structure and properties of glassy carbon

Boron was introduced into glassy carbon by chemical modification and by irradiating the precursor polymer with boron ions. Using chemical modification, a polymer with uniform distribution of boron in the bulk was obtained, whereas irradiation with B³⁺ produced a polymer with boron located in a narrow region under the surface. Following modification with boron, the samples were carbonized at 1273 K and examined using X-ray diffraction, Raman spectroscopy, temperature programmed desorption (TPD) and by hardness measurements. Structural analysis results suggest that boron is mostly substitutionally bonded in the glassy carbon structure regardless of the method used to introduce boron into the polymer precursor. Formation of crosslinks between glassy carbon ribbons during carbonization as a consequence of the recombination of ion beam induced changes in the polymer structure and a high concentration of boron in the subsurface layer is proposed to account for an increase of glassy carbon hardness. An increase in the total amount of surface oxygen groups was observed in the TPD spectra of both boron-modified samples due to an increase in the number of active sites. Results show that the nature of these sites is influenced by the initial distribution of boron in the polymer precursor.     

Development and validation of a quantitative spectrophotometric method to detect the amount of carbon monoxide in treated tuna fish

In recent years carbon monoxide (CO) has been employed by the fishery industry to preserve the fresh appearance of fish products during frozen storage, particularly in vacuum packaged products. CO reacts with oxy-myoglobin to form a stable cherry coloured carboxy-myoglobin complex. We propose a method that allows the quantitative determination of CO in the meat drip of tuna fish by UV–Vis spectroscopy. It consists of: (i) preparations of CO secondary standard solutions titrated against horse heart Mb primary standard solutions; (ii) determination of calibration curves to measure CO concentration in treated and untreated samples. The accuracy of the spectrophotometric method has been evaluated in terms of trueness and precision by using fortified tuna fish samples. The spectroscopic results have been compared with those obtained using a head space gas chromatographic technique (HS-GC–MS). The CO levels measured in tuna fish samples by UV–Vis are substantially lower than those revealed by HS-GC–MS. The origin of this discrepancy is discussed.     

Renal hematoma after shockwave extracorporeal lithotripsy

OBJECTIVE: Renal haematomas after shock wave extracorporeal lithotripsy (SWEL) represent a potentially serious complication. This paper examines those cases of post-SWEL renal haematoma seen in our Centre, analyzing the likely risk factors. PATIENTS AND METHODS: Between May 1988 and June 1996, 12,800 patients were treated with 15100 lithiasis at some level of the urinary tract requiring 16,000 SWEL sessions. All treatments were done with a Dornier HM-4 lithotripter. Voltage applied ranged from 18 to 26 Kv, averaging 2500 waves/session. Complementary testing (ultrasound/computerised tomography) was requested immediately after treatment if clinical complications were suspected. RESULTS: A total of 10 renal haematomas (0.078%) were diagnosed. Six cases were mild, but 4 presented extensive haematoma with significant haemodynamic consequence. Although in one case nephrectomy was undertaken to control haemorrhage, death finally occurred by disseminated intravascular coagulation. Four patients who developed haematoma were hypertensive and 3 had a previously corrected haemostasis alteration. CONCLUSIONS: The possibility of renal haematoma should be taken into account in the face of persistent and unjustified pain after SWEL treatment. Normalization of blood pressure values, correction of urinary infection as well as adequate correction of haemostatic disorders is advisable.     

Metric semantics from partial order semantics

In dealing with denotational semantics of programming languages partial orders resp. metric spaces have been used with great benefit in order to provide a meaning to recursive and repetitive constructs. This paper presents two methods to define a metric on a subset of a complete partial order such that is a complete metric spaces and the metric semantics on coincides with the partial order semantics on when the same semantic operators are used. The first method is to add a ‘length’ on a complete partial order which means a function of increasing power. The second is based on the ideas of [11] and uses pseudo rank orderings, i.e. monotone sequences of monotone functions . We show that SFP domains can be characterized as special kinds of rank orderded cpo's. We also discuss the connection between the Lawson topology and the topology induced by the metric. Received 11 July 1995 / 1 August 1996     

Friendship: An old concept with a new meaning?

Today many young people form and maintain what they consider friendships through the net. Internet friendship appears to some as modifying the meaning of real friendship and replacing it with something more trivial. In this paper we explore the complexity of online friendship. We start by seeking to gain an understanding of why and how friendship relates to wellbeing. We then look at how friendships are formed, focusing on the concepts of propinquity and homophily and how they play out within the context of online friendships. We delineate the major dimensions of friendship that have emerged in theory and research and then comment on how these features of friendship may be affected by the advent of widespread electronic communication. The differences between offline and online companionship, social support, tangible support and protection, exclusiveness, conflict resolution and relationship stability are also considered. The chapter concludes with a discussion of the challenges of conducting research on the behaviour of children and young people on the Internet and the difficulties in defining the term “friendship.”     

Learning metamorphic malware signatures from samples

Journal of Computer Virology and Hacking Techniques - Metamorphic malware are self-modifying programs which apply semantic preserving transformations to their own code in order to foil detection...     

Functional properties of soybean and lupin protein concentrates produced by ultrafiltration-diafiltration

Ultrafiltration followed by diafiltration (UF-DF) was evaluated for the production of protein products from partially defatted soybean meal or undefatted lupin (Lupinus albus L.2043N) meal. This study determined the effects of UF-DF on functional properties of the extracted proteins and compared the results with those of protein prepared by acid-precipitation (AP). UF-DF produced only protein concentrates (73% crude protein, dry basis, db), while AP produced protein isolates (about 90% crude protein, db). Soybean protein produced by UF-DF showed markedly higher values for solubilities up to pH 7.0, surface hydrophobicity index, emulsion activity index, and foaming capacity than did the AP soybean protein. UF-DF soy protein was also the most heat-stable among all protein samples tested. With lupin proteins, only the surface hydrophobicity and emulsion activity indices were significantly improved by using UF-DF. UF-DF generally had no adverse effects on, and in most cases even improved, the functional properties of soy protein concentrate produced by this method. UF-DF did not produce a comparable improvement in functional properties of lupin proteins as it did for soybean protein.     

Effects of cooking and screw-pressing on functional properties of Cuphea PSR23 seed proteins

This investigation determined the effects of oil processing conditions on some functional properties of Cuphea PSR23 seed proteins to evaluate their potential for value-added uses. Flaked Cuphea seeds were cooked at 82°C (180°F) for 30, 75, or 120 min in the seed conditioner and then screw-pressed to extract the oil. Cooked flakes and press cakes were analyzed for proximate composition and protein functional properties. Results were compared with those of unprocessed ground, defatted Cuphea seeds. Protein from unprocessed Cuphea seeds had excellent emulsifying properties, poor foaming properties, poor solubility (10%) at pH 4–7, and much greater solubility at pH 2 and 10 (57 and 88%, respectively). Solubility profiles showed that cooking the flaked seeds to 82°C for 30 min resulted in a 50–60% reduction in soluble proteins. Cooking for 120 min gave <6% soluble proteins at all pH levels. Cooking for 75 min gave good oil yields but also resulted in <10% soluble proteins at pH 2–7 and 25% soluble proteins at pH 10. Seed cooking and screw pressing during oil extraction had significant detrimental effects on the solubility of Cuphea seed protein but generally improved its foaming capacity and emulsifying activity.     

Using MDA for integration of heterogeneous components in software supply chains

Software product lines are increasingly built using components from specialized suppliers. A company that is in the middle of a supply chain has to integrate components from its suppliers and offer (partially configured) products to its customers. To satisfy both the variability required by each customer and the variability required to satisfy different customers’ needs, it may be necessary for such a company to use components from different suppliers, partly offering the same feature set. This leads to a product line with alternative components, possibly using different mechanisms for interfacing, binding and variability, which commonly occurs in embedded software development.     

Electric strength of vacuum systems with Co-Mo alloy coated Cuelectrodes

The paper presents the results of investigations of the electric strength at 50 Hz AC voltage of vacuum insulation systems that were not subjected to conditioning. The experiments have shown that a Co-Mo alloy coating electrolytically deposited on the surface of copper electrodes causes, at the pressure 2 mPa, >25% increase of electric strength of unconditioned vacuum insulation systems. This breakdown strength decreases with increasing gap spacing between the electrodes, and amounts ~17 kV/mm for systems with Cu electrodes at the electrode gap of 1 mm, and ~9 kV/mm at a gap of 6 mm. Plane electrodes with rounded-off edges of Rogowski's profile were used in the investigations. The electrodes with 50 mm diameter, were made of OFHC Cu. The paper shows the influence of the value of pressure from ~1 mPa to 1 Pa and at constant pressure of ~1 mPa, the length of vacuum gap, and the presence of a Co-Mo alloy layer coating the electrodes