Dataset for the characterisation of thermal stratification in horizontally configured electric water heaters.

A test station was designed and built to measure the thermal stratification (vertical thermal gradients) in a horizontal 150 L electric water heater storage device for different external environmental and user-emulating inputs, ambient temperature, inlet water temperature, water draw flow rate, thermostat temperature and heating coil active time. Stratification measurement consists of 66 temperature sensors that coarsely map three-dimensional temperature gradients within the horizontally configured heating device, under different operational conditions. Other significant temperatures such as inlet, outlet, ambient, thermostat feedback, and wall temperatures were also recorded. An ambient temperature control (climatic) chamber was built to emulate the environmental conditions. A custom-built controller was used to control thermal actuators, the power to the thermostat and the state of the outlet valve. In addition, it also acted as a data acquisition system, responsible for recording all relevant sensor data that was present in the system as well as the test station operating states. The dataset includes heating and thermostat control data and the corresponding thermal stratification profiles under static operating conditions (no water draw) at different ambient temperatures (20 °C, 30 °C, and 40 °C). Additionally, dynamic operating conditions (with water draw) are recorded, maintaining inlet water temperatures at approximately 10 °C and 30 °C. The dataset highlights thermal profiles with and without thermostat control and ambient cooling data without thermostat control. Existing research primarily focuses on vertically oriented water heaters, with limited attention to thermal modelling and data acquisition in horizontal configurations. This work provides valuable insights into the internal thermal dynamics of horizontally configured electric water heater storage devices, widely used worldwide.

Development of a Nested Quantitative Real-Time PCR for Detecting Phytophthora cinnamomi in Persea americana Rootstocks.

Phytophthora cinnamomi causes Phytophthora root rot (PRR) in avocado (Persea americana), an important disease that causes severe economic losses to the avocado industry globally. To date, no PRR-resistant avocado rootstock variety has been discovered, although certain rootstock varieties have been shown to be more tolerant than others. In this study, we developed an accurate, low cost assay for in planta quantification of P. cinnamomi to evaluate disease tolerance. A nested real-time polymerase chain reaction assay was developed to sensitively detect pathogen DNA in plant tissues. Root samples from a highly tolerant (Dusa) and less tolerant (R0.12) rootstock were collected at 0, 3, 7, 14, and 21 days after inoculation with P. cinnamomi and used for pathogen quantification. Nested primers developed in this study were specific and sensitive and could detect P. cinnamomi in root tissues. The amount of P. cinnamomi quantified in roots was significantly higher in the less-tolerant R0.12 plants when compared with the highly tolerant Dusa plants at all time points. This study has confirmed the known status of disease tolerance of Dusa and R0.12 avocado rootstocks in a quantitative manner and provides a reliable molecular tool to assist with industry breeding programs for the selection of PRR-resistant avocado rootstock varieties.

Characterization of the Mercury pulsed power x-ray source spectrum using multichannel density aerogel Cherenkov detectors.

The Aerogel Cherenkov Detector for Cygnus (ACD/C) is a time-dependent, x-ray spectral detector that uses SiO2 aerogels spanning an index of refraction (n = 1.02-1.07) corresponding to a 1.1-2.3 MeV x-ray energy threshold. The ACD/C was developed for pulsed power x-ray sources like Cygnus located at the Nevada National Site and Mercury located at the Naval Research Laboratory (NRL). Aerogels sit between the measurement capabilities of gas (>2 MeV) and solids such as fused silica (>0.3 MeV). The detector uses an aluminum converter to Compton scatter incoming x-rays and create relativistic electrons, which produce Cherenkov light in an aerogel or a fused silica medium. The ACD/C was fielded at the NRL when Mercury was tuned to produce up to 4.8 MeV endpoint bremsstrahlung. Despite a high radiation and electromagnetic interference background, the ACD/C was able to achieve high signal over noise across five aerogel densities and fused silica, including a signal to noise for a 1.1 MeV aerogel threshold. Previous experiments at Cygnus observed a signal that was comparable to the noise (1×) at the same threshold. The ACD/C observed time-resolved rise and fall times for different energy thresholds of the photon spectrum. Monte Carlo simulations of the ACD/C's aerogel response curves were folded with a simulation of Mercury's photon energy spectrum and agree within the error to the observed result.

New microsatellite markers for population studies of Phytophthora cinnamomi, an important global pathogen.

Phytophthora cinnamomi is the causal agent of root rot, canker and dieback of thousands of plant species around the globe. This oomycete not only causes severe economic losses but also threatens natural ecosystems. In South Africa, P. cinnamomi affects eucalyptus, avocado, macadamia and indigenous fynbos. Despite being one of the most important plant pathogens with a global distribution, little information is available regarding origin, invasion history and population biology. This is partly due to the limited number of molecular markers available for studying P. cinnamomi. Using available genome sequences for three isolates of P. cinnamomi, sixteen polymorphic microsatellite markers were developed as a set of multiplexable markers for both PCR and Gene Scan assays. The application of these markers on P. cinnamomi populations from avocado production areas in South Africa revealed that they were all polymorphic in these populations. The markers developed in this study represent a valuable resource for studying the population biology and movement of P. cinnamomi and will aid in the understanding of the origin and invasion history of this important species.

Measuring 10-20 T magnetic fields in single wire explosions using Zeeman splitting.

We have shown that the Zeeman splitting of the sodium (Na) D-lines at 5890 Å and 5896 Å can be used to measure the magnetic field produced by the current flowing in an exploding wire prior to wire explosion. After wire explosion, the lines in question are either not visible in the strong continuum from the exploding wire plasma, or too broad to measure the magnetic field by methods discussed in this paper. We have determined magnetic fields in the range 10-20 T, which lies between the small field and Paschen-Back regimes for the Na D-lines, over a period of about 70 ns on a 10 kA peak current machine. The Na source is evaporated drops of water with a 0.171 M NaCl solution deposited on the wire. The Na desorbs from the wire as it heats up, and the excited vapor atoms are seen in emission lines. The measured magnetic field, determined by the Zeeman splitting of these emission lines, estimates the average radial location of the emitting Na vapor as a function of time under the assumption the current flows only in the wire during the time of the measurement.

Measuring 20-100 T B-fields using Zeeman splitting of sodium emission lines on a 500 kA pulsed power machine.

We have shown that Zeeman splitting of the sodium (Na) D-lines at 5890 and 5896 Å can be used to measure the magnetic field (B-field) produced in high current pulsed power experiments. We have measured the B-field next to a return current conductor in a hybrid X-pinch experiment near a peak current of about 500 kA. Na is deposited on the conductor and then is desorbed and excited by radiation from the hybrid X-pinch. The D-line emission spectrum implies B-fields of about 20 T with a return current post of 4 mm diameter or up to 120 T with a return current wire of 0.455 mm diameter. These measurements were consistent or lower than the expected B-field, thereby showing that basic Zeeman splitting can be used to measure the B-field in a pulsed-power-driven high-energy-density (HED) plasma experiment. We hope to extend these measurement techniques using suitable ionized species to measurements within HED plasmas.

Prediction of human mRNA donor and acceptor sites from the DNA sequence.

Artificial neural networks have been applied to the prediction of splice site location in human pre-mRNA. A joint prediction scheme where prediction of transition regions between introns and exons regulates a cutoff level for splice site assignment was able to predict splice site locations with confidence levels far better than previously reported in the literature. The problem of predicting donor and acceptor sites in human genes is hampered by the presence of numerous amounts of false positives: here, the distribution of these false splice sites is examined and linked to a possible scenario for the splicing mechanism in vivo. When the presented method detects 95% of the true donor and acceptor sites, it makes less than 0.1% false donor site assignments and less than 0.4% false acceptor site assignments. For the large data set used in this study, this means that on average there are one and a half false donor sites per true donor site and six false acceptor sites per true acceptor site. With the joint assignment method, more than a fifth of the true donor sites and around one fourth of the true acceptor sites could be detected without accompaniment of any false positive predictions. Highly confident splice sites could not be isolated with a widely used weight matrix method or by separate splice site networks. A complementary relation between the confidence levels of the coding/non-coding and the separate splice site networks was observed, with many weak splice sites having sharp transitions in the coding/non-coding signal and many stronger splice sites having more ill-defined transitions between coding and non-coding.

G+C-rich tract in 5' end of human introns.

Analysis of an artificial neural network trained to classify DNA as coding or non-coding revealed compositional differences between sequence parts translated into protein and those that were not. The 5' end of human introns was found to have a base composition that was non-random to an extent matching the non-randomness in the 3' end that contains the polypyrimidine tract. The prevailing nucleotides in the initial 50 nucleotides of human introns are guanine and cytosine, the trinucleotide GGG was found to occur almost four times as frequently as it would in sequences with a uniform distribution of the nucleotides. The initial part of terminal exons and their associated terminal introns were shown to have a very special base composition deviating strongly from the normal picture in other exons and introns.

Neural network model of the genetic code is strongly correlated to the GES scale of amino acid transfer free energies.

A neural network trained to classify the 61 nucleotide triplets of the genetic code into 20 amino acid categories develops in its internal representation a pattern matching the relative cost of transferring amino acids with satisfied backbone hydrogen bonds from water to an environment of dielectric constant of roughly 2.0. Such environments are typically found in lipid membranes or in the interior of proteins. In learning the mapping between the codons and the categories, the network groups the amino acids according to the scale of transfer free energies developed by Engelman, Goldman and Steitz. Several other scales based on internal preference statistics also agree reasonably well with the network grouping. The network is able to relate the structure of the genetic code to quantifications of amino acid hydrophobicity-hydrophilicity more systematically than the numerous attempts made earlier. Due to its inherent non-linearity, the code is also shown to impose decisive constraints on algorithmic analysis of the protein coding potential of DNA.

Chelator effect on ion diffusion in ferrous-sulfate-doped gelatin gel dosimeters as analyzed by MRI.

Ferrous-sulfate-doped gelatin gel dosimeters are useful tools for the measurement of three-dimensional absorbed radiation dose distributions. The diffusion of ferric ions through these gels causes degradation with time of the dose distribution image. It would be useful to reduce ferric ion diffusion without decreasing gel sensitivity. The amount of ferric ion diffusion is a function of the time delay after radiation, the gel temperature, and the gel concentration. These effects can be quantified by measuring the ferric ion diffusion coefficient. Determination of the diffusion coefficient by irradiating the lower section of a cylinder of gel, which was then imaged repeatedly over time with a clinical magnetic resonance imager, is described. Analysis of the edge spread function formed at each of several times after irradiation by drawing a profile over the imaged junction between the irradiated and unirradiated halves of the cylinder, gave estimates of the variance of the edge spread function. These variances were used to obtain an estimate of the ferric ion diffusion coefficient for the gel. A method of reducing ferric ion diffusion by adding a chelator and the cross linkage agent formaldehyde is suggested. The chelators investigated were 1,10 phenanthroline, xylenol orange, and bathophenanthroline disulfonic acid. These reduced diffusion to varying extents, and influenced the gel sensitivity. The diffusion coefficient in gels containing xylenol orange was found to be 0.44 mm2h-1. The gel sensitivity was 0.0093 s-1Gy-1. This compared with a diffusion coefficient of 0.82 mm2h-1 for the base line gel that did not contain formaldehyde or chelators. The sensitivity of this base line gel was 0.0129 s-1Gy-1. The addition of xylenol orange produced the most improved gel dosimeter of the gels studied. This gel had a decreased ferric ion diffusion coefficient and a decreased sensitivity. It was still sensitive enough to be useful.

Evolution equations and ultrasonic wave propagation in biological tissues.

Fundamental research in ultrasonic diagnostics is often limited by the relatively simple models of propagation invoked in what is largely an empirical science. Careful discussion of the problem reveals the need for more sophisticated propagation theories as the basis of measurement techniques and for the interpretation of experimental results. It is thus important for dialogue between theoreticians and experimentalists in the field. The complexity of ultrasonic wave propagation in tissue arises from a combination of factors. First, there is the biochemical sophistication of the media concerned. Second, there is the variety of physical phenomena involved: the diffractive nature of the ultrasonic field, the presence of absorption, the presence of large scale inhomogeneities and small scale scatterers, and the possibility of finite amplitude propagation effects. It has tended to be the custom to deal with each of these problems on an individual basis with a second feature being introduced as a perturbation of the results obtained for the first. The present authors have been concerned to find a unified approach which will permit each of the effects to be taken into account in relation to the others. This approach is based on the application of two-dimensional evolution equations modelling ultrasonic propagation in non-cavitating soft tissues. The model incorporates all the propagation phenomena known from experimental studies, indicating a need for knowledge of nine material parameters for a complete description. It thus provides a basis for numerical investigation of the relative significance of the parameters under different conditions. This will permit identification of those that should be known experimentally with high precision and those that have a minor role in the propagation phenomena.

Technical note: computed tomography imaging with a radiotherapy simulator.

An inexpensive system for obtaining cross-sectional information and accurate body outlines of patients destined for radiotherapy, using a radiotherapy simulator without any major modifications, has been investigated. The image intensifier of the simulator was moved laterally and a narrow fan beam of X-rays passed through the phantom onto the intensifier. Several television (TV) lines of the video signal from the TV camera were digitized by a frame grabber and stored for reconstruction. Multiple projections were acquired by rotating the gantry of the simulator. The field of view was enlarged by increasing the offset distance of the image intensifier and taking two sets of projections. Reconstruction was carried out by using the convolution and back-projection method. The gradient between pixel values in the reconstructed images was used to detect the outlines of structures in the images. The accuracy of outline detection was evaluated with images of a Rando phantom. The outlines of the images were compared with the actual outlines of the phantom. The spatial resolution of the simulator computed tomography (CT) was measured to be 4.05 mm. Large inhomogeneities could be clearly seen. The average difference between the measured and the actual outlines was 3.0 mm with a maximum difference of 10.0 mm at sharp curves in the outline. The simulator CT provides an inexpensive, alternative method of obtaining body outlines and does not require any modifications to the simulator. Data acquisition, processing and display can be performed on a personal computer with image processing facilities.

[More power for patients: the patients' forum--a joint platform for the medical profession and patient self-help groups]. / Mehr Power für Patienten: Patientenforum--Gemeinsame Plattform von Arzteschaft und Patientenselbsthilfe.

New ways of cooperation between doctors and representatives of patients are followed with the help of the patients' forum which was founded on the initiative of the German Medical Association. Members of the German Association 'Help for the Handicapped People', the 'Forum of the Chronic Ill and Handicapped People' of the 'Equal Charitable Organisation' (Paritätischer Wohlfahrtsverband), the 'German Association of Self-Help Groups' as well as representatives of the committees and the management of the German Medical Association and the National Association of Statutory Health Insurance Physicians form the patients' forum. The major aim of this cooperation is to discuss the possibilities and the ways to improve the quality in health care. A direct participation of patients' representatives is for the moment planned in the evaluation of the quality of medical information for the lay public. In cooperation with the Agency for Quality in Medicine--a joint institution of the German Medical Association and the National Association of Statutory Health Insurance Physicians--the quality of information on health care that is published in the internet should be examined. The patients' information service which was developed by the Agency for Quality in Medicine and is found under www.patienten-information.de is the basis for this examination.

A neural network method for identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites.

We have developed a new method for the identification of signal peptides and their cleavage sites based on neural networks trained on separate sets of prokaryotic and eukaryotic sequences. The method performs significantly better than previous prediction schemes, and can easily be applied to genome-wide data sets. Discrimination between cleaved signal peptides and uncleaved N-terminal signal-anchor sequences is also possible, though with lower precision. Predictions can be made on a publicly available WWW server: http://www.cbs.dtu.dk/services/SignalP/.

The posterior interosseous flap for soft-tissue cover of the hand.

The management of soft-tissue defects of the hand with exposed bone and tendons may be difficult. The posterior interosseous flap is a fasciocutaneous island from the dorsal forearm, based on the posterior interosseous vessels. We have used this flap as a one-stage procedure to cover soft-tissue defects of the hand in 6 patients. It provides excellent cover without sacrificing a major blood vessel such as the radial artery. Although the vascular anatomy of the flap is normally consistent, variations exist. This prevented elevation of 1 of the flaps in our series.