Structural and magnetic properties of bulk Mn2PtSn.

Interplay between structural and magnetic order parameters is one of the key mechanisms of tuning properties of materials intended for device applications in spintronics. Here, using density functional calculations, we study combined effects of tetragonal distortion and non-collinear magnetic order in Mn2PtSn. We show that this material has two energetically close energy minimums corresponding to tetragonal lattice. In one of these phases, Mn2PtSn exhibits ferrimagnetic order with nearly fully compensated total magnetic moment, while in the other phase that corresponds to the lowest energy, a non-collinear magnetic arrangement emerges, with very large canting angle of the Mn local magnetic moments. The non-collinear alignment is explained through the interplay of exchange couplings between nearest and next nearest neighbor Mn atoms. Results are compared with those reported in recent literature, both experimental and theoretical.

Left subclavian flap aortoplasty for coarctation of the aorta: effects on forearm vascular function and growth.

This study evaluated vascular function and growth of the forearm in nine children (mean age 9.2 years) who had undergone left subclavian flap aortoplasty for the infantile type of coarctation of the aorta many years (mean 9.0) earlier. Variables used to investigate bilateral forearm vascular function included forearm blood flow and resistance measured by strain gauge plethysmography under rest conditions, in response to 30 s of static handgrip exercise at 40% maximal voluntary contraction and in response to 10 min of forearm arterial occlusion (that is, the reactive hyperemic blood flow response). Forearm growth was ascertained by measuring right and left forearm volumes, lengths, circumferences and skinfold thickness. Mean arterial pressure at rest in the right and left arms differed by 9% (right 78.2 +/- 2.1, left 71.0 +/- 2.7 mm Hg; p less than 0.05). Forearm blood flow, however, was not significantly different between the surgically altered left arm and the normal right arm under any of the study conditions. Likewise, forearm vascular resistance was not statistically different under any conditions, although the left arm tended to have a lower resistance at rest (right 23.5 +/- 3.2, left 18.7 +/- 2.0 mm Hg.min.100 ml/ml; p = 0.057). Left forearm anthropometric measurements showed a 9% reduction in volume and a 3% reduction in circumference and length. In addition, skinfold thickness tended to be larger on the left arm, suggesting that this limb had a smaller muscle mass. In conclusion, early repair with a subclavian flap does not impair vascular function in the altered limb and is associated with only minor reductions in forearm growth variables. Hence, left subclavian flap aortoplasty appears to be a safe and effective procedure for repair of coarctation of the aorta.

Muscle acidosis during static exercise is associated with calf vasoconstriction.

In this study we measured (n = 6) the phosphocreatine-to-inorganic phosphate ratio (PCr/Pi), Pi, and pH with 31P-nuclear magnetic resonance (31P-NMR) in the human forearm during static work at 30% of maximal voluntary contraction (MVC) for 2 min followed immediately by 3 min of circulatory arrest (forearm arterial occlusion). Static exercise, with its central volitional and skeletal muscle metabolic and mechanical afferent components, caused a rise in heart rate (HR, 32%), blood pressure (BP, 29%), and calf vascular resistance (calf R, 30%). During forearm occlusion after static exercise, HR returned to base line, the increase in BP was attenuated by 30%, and calf R remained elevated and unchanged. The percent change in calf R was correlated with forearm cellular pH (R = 0.56, P less than 0.001) but only weakly associated with PCr/Pi (R = 0.33, P less than 0.042). 30% MVC for 1 min followed by arterial occlusion (3 min) reduced PCr/Pi by 65% and pH by 0.16 U (P less than 0.05). Calf R was unchanged. Circulatory arrest alone (20 min) caused no change in either pH or calf R but large changes in PCr/Pi (50% reduction). We conclude that 1) there is an association between forearm cellular acidosis and calf vasconstriction during static forearm exercise and 2) large changes in PCr/Pi without concomitant changes in pH are not associated with changes in calf R.

Summary of ICD-9-CM Coordination and Maintenance Committee meeting.

The ICD-9-CM Coordination and Maintenance Committee, cosponsored by the National Center for Health Statistics (NCHS) and the Health Care Financing Administration (HCFA), recently met in Baltimore, MD. Donna Pickett, RRA (NCHS), and Patricia Brooks, RRA (HCFA), cochaired the meeting. Proposed modifications to ICD-9-CM were presented and are summarized below. Unless otherwise indicated, the audience generally supported the proposed changes.

AHIMA provides testimony on coding/classification issues pertaining to HIPAA (Health Insurance Portability and Accountability Act of 1996) implementation.

In summary, AHIMA has identified the following key issues: Uniformity and consistency must be required of all health-care organization, payers, and other data users. A central authority, comprised of representatives from the public and private sector, should be created to ensure compliance with and enforcement of coding system rules and official coding guidelines. A realistic implementation plan for the introduction of any new coding system, including migration to a single procedural classification system, must be established. Since data quality is based on the data source, clinical vocabulary, and classification system, it is important not to focus on only one component. A standard data set must be established. It is important to maintain data comparability with other nations in order to conduct global research studies. AHIMA has had a long-standing relationship working with the department on coding and classification issues and is committed to providing assistance to carry out out the requirements of the law.