A Novel Inverse-Magnetostrictive Force Sensor

The change in magnetic permeability of a material under stress (inverse magnetostriction) offers the potential for a high-performance, low-cost force sensor capable of being used in harsh real-world environments. The existing force sensor technologies are limited in their use in commercial products by either cost issues or susceptibility to electromagnetic noise. Inverse Magnetostriction has been used to measure strain in controlled environments since its discovery by Joule in 1847, but not in practical applications due to a lack of data on how magnetic material properties change with environmental conditions such as temperature. Utilizing an innovative noise-reducing self-inductance design, this paper presents the basis for an inverse-magnetostrictive compressive load sensor. A lumped-parameter model for the change in sensor inductance under load, due to both mechanical and magnetic effects, is derived. The material properties of a magnetostrictive iron alloy are empirically determined over a broad range of loads and temperatures. The model and material properties are confirmed by testing a prototype force sensor. The prototype measures compressive forces from 100 to 25 000 N over a temperature range of 20 degC to 120 deg with a typical error of +/-2% (4% max). The sensor does experience significant thermal hysteresis for which the model does not currently account. This work was motivated by the need for a force sensor in an automobile electric brake system and used a single iron alloy (50% Ni), but the model and testing procedure provide a roadmap for future research to improve the performance and capabilities of such a sensor     

Transferability of results of small scale experiments to real structures

Numerical evaluations in combination with experiments on the basis of the J-integral methods are a necessary step in the chain of transferability from small specimens to real structures.For three cases, single-edge notched specimens of different thicknesses, flat plates under tension containing two through-cracks and side-grooved compact specimens of various steels, both finite element calculations including crack growth and experiments using the partial unloading technique were performed.The results show a good agreement of the experimental and numerical J-values and confirm the experimental procedure to evaluate J from the work done on the specimen.Moreover, for the single-edge notched specimen the strong influence of the angular stiffness of the loading system on the specimen behaviour is demonstrated.     

Antiestrogen action: differential nuclear retention and extractability of the estrogen receptor

Since there is a much longer uterine nuclear retention of the U-11, 100A (antiestrogen) receptor complex (UARC) than of the estradiol receptor complex (ERC) at 4-12 hrs after injection, experiments were designed to determine if there is a difference between the relative nuclear affinities for the two RCs as determined by extraction with various ionic strength mediums. Although the UARC was retained longer in the nuclear fraction in vivo, the UARC was completely extractable with 0.3M KCl or 50mM spermine, whereas the ERC demonstrates a salt-resistant form. This suggests that the ERC is more tightly bound to nuclear components through this salt-resistant form of the receptor. In addition, various intercalating agents were used to distinguish the different nuclear chromatin DNA sites where the UARC and ERC may be binding. With actinomycin D (50 uM) more ERC than UARC was retained in the nuclear fraction. However, with ethidium bromide (100uM) less ERC than UARC was retained. Also, the ERC selectively released by ethidium bromide is precisely that fraction not released by salt. These results indicate that the UARC and ERC bind to different chromatin loci.     

In vivo quantification of brain volumes in subcortical vascular dementia and Alzheimer''s disease. An MRI-based study

Ibuprofen is one of the most effective and widely used non-steroidal analgesic and anti-inflammatory agent. It is marketed as a racemic mixture though it is known that the pharmacological activity resides in the (S)-(+)-enantiomer only. Several direct/indirect liquid chromatographic methods involving a variety of chiral/achiral phases along with their possible role in resolution, chiral and achiral agents used for derivatisation have been discussed with special reference to ibuprofen, and mentioning their application to the resolution of other 2-aryl-propionic acids/profens.     

Exploring the Potential of Norbornene‐Modified Mannosamine Derivatives for Metabolic Glycoengineering

Metabolic glycoengineering (MGE) allows the introduction of unnaturally modified carbohydrates into cellular glycans and their visualization through bioorthogonal ligation. Alkenes, for example, have been used as reporters that can react through inverse‐electron‐demand Diels–Alder cycloaddition with tetrazines. Earlier, norbornenes were shown to be suitable dienophiles; however, they had not previously been applied for MGE. We synthesized two norbornene‐modified mannosamine derivatives that differ in the stereochemistry at the norbornene (exo/endo linkage). Kinetic investigations revealed that the exo derivative reacts more than twice as rapidly as the endo derivative. Through derivatization with 1,2‐diamino‐4,5‐methylenedioxybenzene (DMB) we confirmed that both derivatives are accepted by cells and incorporated after conversion to a sialic acid. In further MGE experiments the incorporated sugars were ligated to a fluorophore and visualized through confocal fluorescence microscopy and flow cytometry.     

Einfluss einer elektronischen Patientenakte (EPA) auf das Arzt-Patienten-Verhältnis: eine systematische Übersicht der medizinethischen Implikationen

Background

In a model project, the implementation of a comprehensive, personal electronic patient record (PEPA) shall not only improve consistency of care, but also realize the right to informational self-determination to the effect that every patient is made administrator of a data-cloud containing all his medical data. A systematic literature review on the topic “electronic health records (EHR)” anticipates possible ethical challenges in connection with the mentioned PEPA. Of the initial 2487 publications, 51 articles were analyzed: 30 empirical studies, 10 medical ethics analyses, and 11 comments.

Results

In the empirical studies, a more comprehensive medical record was described as an initial effect. The option for access to the EMR by the patient resulted in a better understanding of the needed medical care and thereby higher compliance by the patient. An improvement of the quality of medical care was attributed to prevention of medical errors through the access to records by the patient, a more effective utilization of physician–patient visitations and an improved understanding of the therapeutic concept. Studies also showed a strengthening of the bond of trust in the physician–patient relationship. Concerns were related to data security, possible decline in the personal physician–patient relationship and potential excessive demands on the patient.

Discussion

In an assessment of the EMR, weighing beneficence against patient autonomy plays a major role. Concerns by medical ethics pertaining to a loss of trust or a disturbance of the physician–patient relationship could not be proven empirically. The feared risks to data security were weighed by those affected in favor of the potential benefits of the EMR. Provided that data are protected, the PEPA has the potential to influence the physician–patient relationship positively through participation of the patient. The specific ethical challenges associated with the co-administration of PEPA will be examined in the pilot project.

     

An improved method of scaling for real-time signal processingapplications

Implementing digital signal processing algorithms using fixed-point arithmetic is a difficult task, involving trade-offs to balance the efficiency and noise performance of a given realization. One of the most important components of such design is to minimize the noise generated by quantization and over flow effects. This is generally accomplished by the scaling of signals and coefficients in the fixed-point realization based upon knowledge of signal features and statistics. This paper presents a new method for structuring this design task. It uses a model based on scaled-fractional numbers to simplify both the concepts required to realize fixed-point arithmetic versions of algorithms, as well as the real effort required for such implementations. This model has been implemented as a data type in a high level computer language to allow direct implementation of fixed-point arithmetic versions of algorithms     

Comparison of functional MR-venography and EPI-BOLD fMRI at 1.5 T

Functional magnetic resonance imaging (fMRI) of the brain using blood oxygenation level dependent (BOLD) contrast relies on the changes of paramagnetic deoxyhemoglobin concentration, which affects brain parenchyma and draining venous vessels. These changes in deoxyhemoglobin concentration in venous vessels can also be monitored using a high-resolution susceptibility-based MR-venography technique. Four volunteers participated in the study in which functional MR-venograms were compared with conventional echo-planar imaging (EPI)-BOLD-fMRI. In all cases, small venous vessels could be identified close to the areas of activation detected by conventional fMRI. In the venograms, task performance (finger tapping) resulted in a loss of venous vessel contrast compared to the resting state, which is consistent with a local decrease of deoxyhemoglobin concentration. MR-venography allows a direct visualization of the BOLD-effect at high spatial resolution. In combination with conventional fMRI, this technique may help to separate the contribution of brain parenchyma and venous vessels in fMRI studies.     

Benign prostate hyperplasia: evaluation of treatment response with DCE MRI

Benign prostate hyperplasia (BPH) is a major disease and its non-surgical therapy a major area of interest. The purpose of this study was to establish perfusion parameters in beagles with BPH using dynamic contrast-enhanced (DCE) MRI and to investigate changes due to the effects of finasteride treatment. Twelve male beagles (mean age 4.4±0.9,years) were divided into a control and treatment group that received a daily dose of 1 mg/kg finasteride. DCE MRI was carried out in a clinical scanner using a 3D spoiled gradient echo sequence prior to and during treatment. 0.2 mmol/kg contrast agent (gadoteridol) was administered with an injection rate of 0.2 ml/s followed by a 15 ml flush of saline. Contrast enhancement was evaluated by pharmacokinetic mapping of a two-compartment model with colour overlay images in addition to regional ROI analysis. Quantitative parameters were defined by the amplitude of contrast enhancement A, the exchange rate k_ep and the time to maximum signal enhancement. Dynamic contrast-enhanced MRI investigations of the prostate revealed two distinct zones, an inner, periurethral zone and an outer, parenchymal zone. The periurethral zone is highly vascularized, whereas the parenchymal zone is moderately vascularized when compared to other parenchymal organs. During treatment, in the parenchymal zone the intensity of enhancement (amplitude A) and the time to maximum signal enhancement increased, while the exchange rate k_ep decreased. Dynamic contrast-enhanced MRI of BPH reveals distinct differences between individual zones within the prostate. Moreover, changes during successful treatment suggest increased blood volume per volume of tissue and decreased vessel leakiness.