The effects of early post-mortem pH and ultimate pH on level and amount of destructured zones in cooked cured hams

Effects of early (1 h p.m. and 3 h p.m.) and ultimate pH (24 h p.m.) on level and amount of destructured zones in cooked cured hams were evaluated. In experiment 1, electrically stimulated (50 V, 14 Hz, 2 × 90 s) and non-stimulated carcass halves, both in combination with two cooling procedures (2 °C from 30 min p.m. vs. 120 min p.m.) resulted in 1.5–35.2 g/kg destructured zones in silversides and 58.4–120.0 g/kg destructured zones in topsides. A high temperature 1 h p.m. in silversides (P = 0.067) and topsides (P = 0.054) was identified as the most important predictor for the defect. In experiment 2, cooked cured hams from topsides selected according to ultimate pH groups (pH < 5.5, pH 5.5–5.7, pH > 5.7) showed between 12.3 and 61.8 g/kg destructured zones. Ultimate pH was specified as most important, however, statistically still not significant (P = 0.135) predictor for the defect. Chemical analysis resulted in low crude ash and high dry matter content as being characteristic for the defect.     

Long-range dependence and on-chip processor traffic

Long-range dependence is a property of stochastic processes that has an important impact on network performance, especially on the buffer usage in routers. We analyze the presence of long-range dependence in on-chip processor traffic and we study the impact of long-range dependence on networks-on-chip. long-range dependence in communication traces of processor ips at the cycle-accurate level. We also study the impact of long-range dependence on a real network-on-chip using the SocLib simulation environment and traffic generators of our own. Our experiments show that long-range dependence is not an ubiquitous property of on-chip processor traffic and that its impact on the network-on-chip is highly correlated with the low level communication protocol used.     

INCOME/STAR: Methodology and tools for the development of distributed information systems

INCOME/STAR is an experimental environment for the cooperative development of distributed information systems. This paper presents some of INCOME/STAR's innovative features in the area of information systems engineering: First a new type of high-level Petri nets, so-called Nested Relation/Transition nets (NR/T-nets), is described. NR/T-nets allow the modeling of concurrent processes and related complex structured objects in distributed business applications. New concepts for entity and relationship clustering were developed to support a stepwise top-down approach for Entity/Relationship based object modeling. Distributed multi-user simulation and prototyping are used for the evaluation and analysis of NR/T-nets and the involved object schema. Finally, ProMISE — an evolutionary process model for information system development — is introduced. A role-based groupware component is part of the INCOME/STAR architecture to support communication, organization and social interaction in development projects.     

Non-breath-hold fast spin-echo versus breath-hold fast spin-echo and spoiled gradient-recalled echo MR imaging in the detection of hepatic tumors: correlation with surgical findings

OBJECTIVE: Our objective was to compare the sensitivity of non-breath-hold T2-weighted fast spin-echo with and without fat suppression, breath-hold T2-weighted fast spin-echo without fat suppression, and spoiled gradient-recalled echo (GRE) MR imaging for detecting hepatic tumors using surgical findings as the standard of reference. SUBJECTS AND METHODS: Eighteen patients with 36 surgically proven hepatic tumors had non-breath-hold T2-weighted fast spin-echo (6000/117 [TR/effective TE; echo train length, 16) MR imaging with and without fat suppression, breath-hold T2-weighted fast spin-echo MR imaging (2700/105; echo train length, 20), and spoiled GRE images (10.1/1.9; flip angle, 30 degrees) obtained before and after injection of a gadolinium chelate. Images were analyzed separately by two independent readers, with disagreements resolved by consensus reading. RESULTS: Non-breath-hold T2-weighted fast spin-echo MR imaging with and without fat suppression depicted 22 (61%; 95% confidence interval [CI], 43-77%) and 20 (56%; 95% CI, 37-72%) of 36 hepatic tumors, respectively. Breath-hold T2-weighted fast spin-echo imaging allowed detection of 19 (53%; 95% CI, 35-69%) of 36 hepatic tumors. Unenhanced and gadolinium chelate-enhanced spoiled GRE images allowed depiction of 18 (50%; 95% CI, 33-67%) and 29 (81%; 95% CI, 63-91%) of 36 hepatic tumors, respectively. Gadolinium chelate-enhanced spoiled GRE images allowed depiction of significantly more hepatic tumors than any of the other pulse sequences. CONCLUSION: Gadolinium chelate-enhanced spoiled GRE imaging is more sensitive than T2-weighted MR imaging obtained with a breath-hold or a non-breath-hold technique.     

Hepatic cavernous hemangioma: appearance on T2-weighted fast spin-echo MR imaging with and without fat suppression

OBJECTIVE: The goals of our study were to define the morphologic appearance of cavernous hemangioma of the liver on T2-weighted fast spin-echo MR imaging and to determine if the use of fat suppression may quantitatively and qualitatively modify the MR imaging appearance of cavernous hemangioma. SUBJECTS AND METHODS: Twenty-six patients with cavernous hemangiomas of the liver were prospectively studied with T2-weighted MR imaging with a fast spin-echo technique with and without fat suppression. Thirteen patients had known hemangiomas for more than 2 years, with no change in size or morphology during this period. The remaining 13 patients had diagnoses based on dynamic CT and sonography and an absence of change in the morphology and size of their lesions during follow-up of more than 6 months (range, 6-12 months) after the MR imaging studies. Values for signal intensity and contrast-to-noise (C/N) ratios in cavernous hemangiomas that were obtained with and without fat suppression were compared. Images were qualitatively analyzed separately at identical level and window settings by two interpreters for morphologic features of cavernous hemangiomas. RESULTS: No significant difference was found between signal intensity values obtained using the fat-suppressed fast spin-echo MR imaging technique (5.62 +/- 1.14 [SD]) and those obtained without fat suppression (5.51 +/- 1.23). Values for C/N ratios obtained with the fat-suppressed fast spin-echo MR imaging technique (20.13 +/- 7.63) were significantly superior to those obtained without fat suppression (16.59 +/- 5.31) (p < .001). On T2-weighted fast spin-echo MR imaging without fat suppression, 100% of cavernous hemangiomas were hyperintense relative to the spleen, 90% had well-defined and sharp margins, 55% were isointense to CSF, and 76% were homogeneous. Without fat suppression, 34% of cavernous hemangiomas showed the combination of isointensity to CSF, well-defined margins, and homogeneity. On T2-weighted fast spin-echo MR imaging with fat suppression, all cavernous hemangiomas showed this same combination of features. CONCLUSION: Seventy-six percent of hepatic cavernous hemangiomas were homogeneous on T2-weighted fast spin-echo MR imaging, and 55% were isointense to CSF. However, only 34% of hepatic cavernous hemangiomas showed typical features. Although fat suppression significantly increased the C/N ratio of cavernous hemangiomas of the liver, fat suppression did not affect their morphologic appearance on T2-weighted fast spin-echo MR imaging.     

Medical dictionaries for patient encoding systems: a methodology

Medical language is highly compositional and makes extensive use of common roots, especially Latino-Greek roots. Besides words devoted to common sense, medical language presents some typical characteristics, especially on morphological and semantic aspects of word formation. Morphological decomposition and identification precedes semantic analysis. It is only when these two prerequisites are fulfilled that an attempt to grasp the meaning of a whole expression is made possible. The main aim of the proposed approach is that of coping with 'the lack of coverage of the medical lexical knowledge', in order to help physicians find the correct international classification for diseases (ICD) codes for a written diagnosis. The proposed methodology allows the development of a powerful dynamic dictionary dedicated to natural language processing in the field of diagnoses and narrative procedures. It describes the design of an analyser that can profit from a dictionary. The methods used have proved to be efficient for various classifications, s well as for multiple languages, as the system presently supports French, German, English and Dutch for ICD-9 and ICD-10 classifications.     

Intensity-modulated radiotherapy – a large scale multi-criteria programming problem

Abstract. Radiation therapy planning is often a tight rope walk between dangerous insufficient dose in the target volume and life threatening overdosing of organs at risk. Finding ideal balances between these inherently contradictory goals challenges dosimetrists and physicians in their daily practice. Todays inverse planning systems calculate treatment plans based on a single evaluation function that measures the quality of a radiation treatment plan. Unfortunately, such a one dimensional approach cannot satisfactorily map the different backgrounds of physicians and the patient dependent necessities. So, too often a time consuming iterative optimization process between evaluation of the dose distribution and redefinition of the evaluation function is needed. In this paper we propose a generic multi-criteria approach based on Pareto's solution concept. For each entity of interest – target volume or organ at risk – a structure dependent evaluation function is defined measuring deviations from ideal doses that are calculated from statistical functions. A reasonable bunch of clinically meaningful Pareto optimal solutions are stored in a data base, which can be interactively searched by physicians. The system guarantees dynamic planning as well as the discussion of tradeoffs between different entities. Mathematically, we model the inverse problem as a multi-criteria linear programming problem. Because of the large scale nature of the problem it is not possible to solve the problem in a 3D-setting without adaptive reduction by appropriate approximation schemes. Our approach is twofold: First, the discretization of the continuous problem results from an adaptive hierarchical clustering process which is used for a local refinement of constraints during the optimization procedure. Second, the set of Pareto optimal solutions is approximated by an adaptive grid of representatives that are found by a hybrid process of calculating extreme compromises and interpolation methods. Correspondence to: K.-H. Küfer     

Development of alternative plasma sources for cavity ring-down measurements of mercury

We have been exploring innovative technologies for elemental and hyperfine structure measurements using cavity ring-down spectroscopy (CRDS) combined with various plasma sources. A laboratory CRDS system utilizing a tunable dye laser is employed in this work to demonstrate the feasibility of the technology. An in-house fabricated sampling system is used to generate aerosols from solution samples and introduce the aerosols into the plasma source. The ring-down signals are monitored using a photomultiplier tube and recorded using a digital oscilloscope interfaced to a computer. Several microwave plasma discharge devices are tested for mercury CRDS measurement. Various discharge tubes have been designed and tested to reduce background interference and increase the sample path length while still controlling turbulence generated from the plasma gas flow. Significant background reduction has been achieved with the implementation of the newly designed tube-shaped plasma devices, which has resulted in a detection limit of 0.4 ng/mL for mercury with the plasma source CRDS. The calibration curves obtained in this work readily show that linearity over 2 orders of magnitude can be obtained with plasma-CRDS for mercury detection. In this work, the hyperfine structure of mercury at the experimental plasma temperatures is clearly identified. We expect that plasma source cavity ring-down spectroscopy will provide enhanced capabilities for elemental and isotopic measurements.     

Self-diffusion of transition metals in (Ti,W,Cr)B2 solid solutions

The self-diffusivities of Ti and Cr were determined in (Ti _x W _y Cr _z )B₂ ceramics which are a model system for the development of in-situ reinforced boride ceramics by tailored precipitate formation. Homogeneous solid solutions of composition (Ti_0.3W_0.5Cr_0.2)B₂, (Ti_0.5W_0.3Cr_0.2)B₂, and (Ti_0.4W_0.5Cr_0.1)B₂ were studied in the temperature interval between 1100 and 1500°C, using ion implanted stable ⁴⁹Ti and ⁵⁴Cr isotopes and secondary ion mass spectrometry (SIMS). The diffusivities of each element obey an Arrhenius law. The Cr diffusivities of all three compounds can be fitted to a unique Arrhenius line with an activation enthalpy of 3.5 eV and a low pre-exponential factor of 2×10⁻⁷ m²/s. The Ti diffusivities are smaller by 1–2 orders of magnitude than the Cr diffusivities, showing, however, higher activation enthalpies of 3.9 eV and approximately the same pre-exponential factors. The consequences of the results for the formation kinetics of precipitates in supersaturated (Ti _x W _y Cr _z )B₂ solid solutions are discussed.     

Temperature dependent study of the microwave performance of0.25-μm gate GaAs MESFETs and GaAs pseudomorphic HEMTs

We report on the noise figure, associated gain, and the current gain cutoff frequency for comparable 0.25-μm gate GaAs MESFETs and GaAs pseudomorphic HEMTs (p-HEMTs) as a function of cryogenic temperature. Contrary to previously published results which suggest that p-HEMTs should have a higher electron velocity and a lower noise figure than MESFETs due to the effects of the two-dimension electron gas (2-DEG), we have experimentally verified that this is not the case. We show clear evidence that the transport properties of the 2-DEG in p-HEMTs do not make a significant contribution to the speed enhancement and noise reduction during high-frequency operation of these devices. It is the fundamental InGaAs material properties, specifically the Γ-L valley separation in the conduction band and associated effective mass of the electron in either GaAs or InGaAs channel, which limits the high-field electron velocity and thus the speed and noise performance of the devices