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Biomedical subjects

A Ney

Publications and source records attributed to A Ney.

11 recordsLinked to original sources

Programmable computing with a single magnetoresistive element.

The development of transistor-based integrated circuits for modern computing is a story of great success. However, the proved concept for enhancing computational power by continuous miniaturization is approaching its fundamental limits. Alternative approaches consider logic elements that are reconfigurable at run-time to overcome the rigid architecture of the present hardware systems. Implementation of parallel algorithms on such 'chameleon' processors has the potential to yield a dramatic increase of computational speed, competitive with that of supercomputers. Owing to their functional flexibility, 'chameleon' processors can be readily optimized with respect to any computer application. In conventional microprocessors, information must be transferred to a memory to prevent it from getting lost, because electrically processed information is volatile. Therefore the computational performance can be improved if the logic gate is additionally capable of storing the output. Here we describe a simple hardware concept for a programmable logic element that is based on a single magnetic random access memory (MRAM) cell. It combines the inherent advantage of a non-volatile output with flexible functionality which can be selected at run-time to operate as an AND, OR, NAND or NOR gate.

Journal Article↗

Magnetologic with alpha-MnAs thin films.

Taking advantage of the spin information in present day computing is expected to yield an enormous increase in efficiency. A promising ferromagnetic material compatible with semiconductors for room temperature applications is MnAs. By sensitive cantilever beam magnetometry, we discovered that alpha-MnAs films on GaAs(001) exhibit an additional small out-of-plane component of the magnetization which is magnetically coupled with the dominant in-plane magnetization. We demonstrate that by regarding the two components as independent inputs, the alpha-MnAs layer can be utilized as a logic gate with nonvolatile output. The logic functionality of the layer can be preselected to be AND or OR at run time, thus offering the perspective for programmable magnetologic devices.

Journal Article↗

Ferromagnetism of MnAs studied by heteroepitaxial films on GaAs(001).

Thin epitaxial films of MnAs--promising candidates for the spin injection into semiconductors--are well known to undergo simultaneously a first-order structural and magnetic phase transition at 10-40 degrees C. The evolution of stress and magnetization of MnAs/GaAs(001), both measured quantitatively with our cantilever beam magnetometer at the coexistence region of alpha-MnAs and beta-MnAs, reveal an orthorhombically distorted unit cell of the ferromagnetic phase, which provides important clues on the origin of ferromagnetism in MnAs.

Journal Article↗

Cardiac troponin T isoforms expressed in renal diseased skeletal muscle will not cause false-positive results by the second generation cardiac troponin T assay by Boehringer Mannheim.

The purpose of this study was to determine whether the two monoclonal anti-cardiac troponin T (cTnT) antibodies (MAbs) used in the second generation cTnT assay by Boehringer Mannheim (BM, capture Ab, M11.7; detection Ab, M7) would detect cTnT isoforms expressed in human skeletal muscle in response to chronic renal disease (CRD). cTnT expression was examined in skeletal muscle biopsies obtained from 45 CRD patients, as well as nondiseased human heart (n = 3) and skeletal muscle (n = 3). cTnT proteins were resolved by modified 7.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with the following anti-cTnT MAbs: M11.7; M7; JS-2, Lakeland Biomedical; and 13-11, Duke University. All four antibodies detected the cTnT isoforms (Ta, Te) expressed in human myocardium. In 20 of 45 skeletal muscle biopsies, MAb M11.7 recognized its epitope in one to three proteins, molecular mass 34-36 kDa, designated Te, Td, and Tc; the strongest signal was that of Te. The same proteins were recognized by MAbs JS-2 and 13-11. The BM M7 antibody did not detect the cTnT isoforms in the molecular mass range of 34-36 kDa. However, MAb M7 did detect a cTnT isoform, molecular mass 39 kDa, in 2 of 45 biopsies. This isoform had an electrophoretic mobility similar to the predominant heart cTnT isoform, Ta. We conclude that cTnT isoforms are expressed in the skeletal muscle of CRD patients. However, given the epitopes recognized by the BM MAbs M7 and M11.7 and the variable presence of these cTnT isoforms in skeletal muscle, the second generation BM cTnT assay will not detect these isoforms if they are released from skeletal muscle into the circulation.

Adult↗

Expression of cardiac troponin T isoforms in skeletal muscle of renal disease patients will not cause false-positive serum results by the second generation cardiac troponin T assay.

The purpose of this study was to determine whether the two monoclonal anti-cardiac troponin T (cTnT) antibodies used in the second generation cTnT assay (capture Ab, M11.7; detection Ab, M7) would detect expression of cTnT isoforms in skeletal muscle from chronic renal disease patients. Skeletal muscle biopsies obtained from 45 chronic renal disease patients (as well as human heart muscles and normal human skeletal muscles) were prepared for Western blot analysis and blotted with the following anti-cTnT antibodies: M 11.7; M7; JS-2, Lakeland Biomedical; 13-11, Duke University) and anti-cTnI antibody JS-1. Using the M11.7 Ab, 20 of 45 renal skeletal muscles demonstrated one to three cTnT isoforms, MW34 39 kDa. These findings were confirmed by both the Lakeland and Duke antibodies. However the BM M7 antibody detected, in two of 45 muscles, only a protein with a MW of approximately 39 kDa. All four antibodies demonstrated equivalence in detection the 39 kDa cTnT isoform expressed in heart muscle. None detected any isoforms in normal skeletal muscle. A single cTnI isoform, MW 25 kDa, was detected by JS-1 only in normal adult myocardium. Based on the antibody configuration of the second generation cTnT assay, we conclude that while cTnT isoforms are expressed in human skeletal muscle obtained from chronic renal disease patients, if released into the circulation, they would not be detected.

Adult↗

Long-term results and complications of renal transplantation: the Hennepin experience.

Approximately one sixth of patients receiving renal transplants have a functioning kidney beyond 20 years. Chronic rejection is the predominant cause of late allograft loss. Malignancy, cardiovascular disease, hepatic failure, and infections are the major causes of late death. Early detection and control of the risk factors that contribute to patient death should favorably influence the long-term success of renal transplantation.

Adult↗

Irradiation of bilateral orbital lymphoma: a non-coplanar technique with case reports.

Bilateral synchronous involvement of the orbits by lymphoma is an uncommon event. Therefore, the irradiation techniques for this disease are not well refined. Depending on the technique used, one has to decide between underdosing the anterior segment of the orbit and the frequently involved lacrimal glands or to tolerate shield related in homogeneities in the range of 40 to 50% as well as higher doses to the midline structures, e.g. the optic chiasma. To avoid the above shortcomings we developed a technique by which half the prescribed dose is delivered by pairs of beams angulated in the transverse plane and the other half by pairs of beams angulated in the sagittal plane. Film dosimetry in a phantom confirms that the entire orbit, including its anterior portion, is well covered, the lens is protected, and the dose to the mid-sagittal structures is not increased. The dose inhomogeneity is in the range of 20% which represents a substantial improvement over alternative methods. Two irradiated patients with bilateral orbital lymphoma are presented with local control and no ophthalmic or other side effects as of last follow-up.

Adult↗