A bacteriophage reagent for Salmonella: molecular studies on Felix 01

Felix 01 (F01) is a bacteriophage originally isolated by Felix and Callow which lyses almost all Salmonella strains and has been widely used as a diagnostic test for this genus. Molecular information about this phage is entirely lacking. In the present study, the DNA of the phage was found to be a double-stranded linear molecule of about 80 kb. 11.5 kb has been sequenced and in this region A + T content is 60%. There are relatively few restriction endonuclease cleavage sites in the native genome and clones show this is due to their absence rather than modification. A restriction map of the genome has been constructed. The ends of the molecule cannot be ligated although they contain 5' phosphates. At least 60% of the genome must encode proteins. In the sequenced portion, many open reading frames exist and these are tightly packed together. These have been examined for homology to published proteins but only 1 to 17 shows similarity to known proteins. F01 is therefore the prototype of a new phage family. On the basis of restriction sites, codon usage and the distribution of nonsense codons in the unused reading frames, a strong case can be made for natural selection that reacts to mRNA structure and function.     

Biocompatibility of a lab-on-a-pill sensor in artificial gastrointestinal environments

In this paper, we present a radiotelemetry sensor, designed as a lab-in-a-pill, which incorporates a two-channel microfabricated sensor platform for real-time measurements of temperature and pH. These two parameters have potential application for use in remote biological sensing (for example they may be used as markers that reflect the physiological environment or as indicators for disease, within the gastrointestinal tract). We have investigated the effects of biofouling on these sensors, by exploring their response time and sensitivity in a model in vitro gastrointestinal system. The artificial gastric and intestinal solutions used represent a model both for fasting, as well as for the ingestion of food and subsequent digestion to gastrointestinal chyme. The results showed a decrease in pH sensitivity after exposure of the sensors for 3 h. The response time also increased from an initial measurement time of 10 s in pure GI juice, to ca. 25 s following the ingestion of food and 80 s in simulated chyme. These in vitro results indicate that changes in viscosity in our model gastrointestinal system had a pronounced effect on the unmodified sensor.     

Differential atrial filling after Mustard and Senning repairs. Detection by transcutaneous Doppler ultrasound

The dominance of Mustard's operation for transposition of the great arteries has been challenged by the recent revival of Senning's repair because it promises better long-term results in terms of venous obstruction and atrial haemodynamics. These hypotheses were tested by recording jugular venous flow waveforms transcutaneously in 24 postoperative patients with simple complete transposition using a bidirectional Doppler blood velocimeter. Eight patients had undergone Mustard's operation and 16 the Senning alternative; all had previously had a postoperative cardiac catheterisation. Both groups of patients had similar left ventricular, pulmonary arterial, and systemic venous atrial pressures. No child showed any evidence at catheterisation of either mitral regurgitation or of superior vena caval pathway obstruction. These two findings were endorsed by the transcutaneous Doppler recordings. Jugular venous flow in normal children exhibits two maxima, one of atrial filling during ventricular systole, the other of ventricular filling occurs once the tricuspid valve has opened. Both operative procedures diminished the size of the former phase, but the Mustard did so more. After Mustard's operation forward flow during the atrial filling phase was absent in approximately half the cardiac cycles recorded, and severely diminished in the rest. By contrast, there was approximately a 90 per cent appearance of atrial filling waves after Senning's operation which also provided significantly better atrial function than Mustard's procedure in terms of peak velocity of blood entering the atrium and total atrial filling. It is therefore concluded that both procedures compromise atrial volume and compliance but Senning's repair to a much lesser extent.     

Audit Contract Provisions and Real-Time Cost Reporting in Construction Contracting

With the advent of contracting methods in the construction industry that result in the owner compensating a contractor for “actual costs” as opposed to a lump-sum payment, the owner must protect its interest by taking on the responsibility of confirming amounts actually incurred by the contractor and determining if these amounts are allowable under the terms of the contract. To succeed at such an endeavor, an owner must have a general understanding of contract interpretation, the risk of not incorporating an express audit provision in its contract, and the implications of not implementing a real-time reporting structure. This paper sets forth the benefits of requiring a real-time reporting structure in the owner-contractor agreement.     

Real-Time Signal Estimation From Modified Short-Time Fourier Transform Magnitude Spectra

An algorithm for estimating signals from short-time magnitude spectra is introduced offering a significant improvement in quality and efficiency over current methods. The key issue is how to invert a sequence of overlapping magnitude spectra (a ldquospectrogramrdquo) containing no phase information to generate a real-valued signal free of audible artifacts. Also important is that the algorithm performs in real-time, both structurally and computationally. In the context of spectrogram inversion, structurally real-time means that the audio signal at any given point in time only depends on transform frames at local or prior points in time. Computationally, real-time means that the algorithm is efficient enough to run in less time than the reconstructed audio takes to play on the available hardware. The spectrogram inversion algorithm is parameterized to allow tradeoffs between computational demands and the quality of the signal reconstruction. The algorithm is applied to audio time-scale and pitch modification and compared to classical algorithms for these tasks on a variety of signal types including both monophonic and polyphonic audio signals such as speech and music.     

Atrial fibrillation: overview of therapeutic trials

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia treated by physicians, and a plethora of therapeutic trials deal with selected aspects of its management. This overview attempts to categorize and summarize the available studies. A key to management of AF is a clinical classification schema that provides a framework for application of the available treatment modalities. Such a classification is provided. Antithrombotic trials have demonstrated the remarkable efficacy of warfarin and more modest effect of acetylsalicylic acid for prevention of stroke; these data are summarized. Cardioversion to restore sinus rhythm is an important aspect of management of AF, particularly of persistent and new onset AF. In this review pharmacological cardioversion is emphasized. The data concerning the use of various drugs for pharmacological cardioversion are reviewed. Many, but not all, agents have been shown to have efficacy in this regard, but efficacy with drugs is lower than that with electrical cardioversion and, in the case of amiodarone, may be delayed. For recurrent AF, the two major rhythm management approaches are maintenance of rhythm and heart rate control. Trials of pharmacological and nonpharmacological therapies for these purposes are reviewed and summarized. Management of AF is an active area of research, and the present review is intended as a foundation upon which new information can be added.