Infrared spectroscopy and anharmonic theory of H3 +Ar2,3 complexes: The role of symmetry in solvation.

The vibrational spectra of H3 +Ar2,3 and D3 +Ar2,3 are investigated in the 2000 cm-1 to 4500 cm-1 region through a combination of mass-selected infrared laser photodissociation spectroscopy and computational work including the effects of anharmonicity. In the reduced symmetry of the di-argon complex, vibrational activity is detected in the regions of both the symmetric and antisymmetric hydrogen stretching modes of H3 +. The tri-argon complex restores the D3h symmetry of the H3 + ion, with a concomitant reduction in the vibrational activity that is limited to the region of the antisymmetric stretch. Throughout these spectra, additional bands are detected beyond those predicted with harmonic vibrational theory. Anharmonic theory is able to reproduce some of the additional bands, with varying degrees of success.

[Arrhythmogenic right ventricular dysplasia as a cause of "sudden cardiac death" with survival]. / Arrhythmogene rechtsventrikuläre Dysplasie als Ursache eines überlebten plötzlichen Herztodes.

HISTORY: A 42 year old woman was resuscitated from ventricular fibrillation. 5 months previously she had a syncope. Her nephew had died of sudden cardiac death at the age of 25 years. INVESTIGATIONS: There was no evidence for ST segment elevation, myocardial infarction or pulmonary embolism. The ECG showed right precordial T wave inversion. Coronary artery disease was excluded angiographically. Echocardiography and angiography revealed inferior wall akinesia of the right ventricle with normal left ventricular function and chamber size. Ventricular fibrillation could not be reproduced by programmed stimulation of the right ventricle during an electrophysiologic study. Results of endomyocardial biopsy of the right ventricle showed a focal fibrous infiltration of the myocardium. Magnetic resonance imaging confirmed inferior wall abnormalities of the right ventricle without typical fatty infiltration in the right ventricular myocardium. CLINICAL COURSE: The patient recovered rapidly without neurologic deficits. Arrhythmogenic right ventricular dysplasia was suspected, and a cardioverter defibrillator (ICD) was implanted. Within 6 months after implantation the ICD memory showed no evidence of ventricular fibrillation. CONCLUSION: Arrhythmogenic right ventricular dysplasia is an important cause of ventricular fibrillation with a potential risk of sudden cardiac death in young persons. Concealed arrhythmogenesis as an early manifestation of right ventricular dysplasia is difficult to detect.

[Primary stent implantation in the internal carotid artery]. / Primäre Stent-Implantation in der Arteria carotis interna.

BACKGROUND AND OBJECTIVE: Advances in interventional catheter technology have made it possible to dilate stenoses also in the internal carotid artery (ICA). This may cause cerebral emboli, but primary stent implantation may fixate atherosclerotic material on the vessel wall and thus prevent embolization. PATIENTS AND METHODS: Marked stenosis in the ICA was treated by balloon dilatation in 71 consecutive patients aged between 40 and 85 years (mean 69 +/- 9 years). If possible, a stent was implanted before the first balloon dilatation. RESULTS: A stent was placed before dilatation in 53 of 76 procedures. Dilatation with a small balloon to allow stent placement was necessary in 23. Thus stent implantation before definitive dilatation was successful in all instances. The degree of stenosis was reduced from 79 +/- 11 to 9 +/- 14%. In all procedures the stenosis was reduced to less than 50%. One patient had a severe and two had a mild stroke. One patient died of a myocardial infarction 2 days after the procedure. Thus the neurological complication rate was 3.9% and the death rate 1.3%. Follow-up examination revealed an asymptomatic occlusion of the ICA after two weeks in one patient, a recurrent stenosis after 6 months in two of 46 patients. In all other patients the degree of stenosis was less than 50% at 6 months. CONCLUSION: Primary stent placement before balloon dilatation in ICA stenosis was possible in the majority of patients. This procedure would thus seem to reduce the risk of thromboembolic complications.

Improving the flavor of calcium chloride and lactic acid injected mature beef top round steaks.

The effect of added commercial beef flavoring on the physical and sensory characteristics of CaCl(2) and lactic acid injected cow meat was investigated. A 10% injection of 0.3 M CaCl(2) and 0.3 M lactic acid into hot-boned top rounds (m. semimembranosus) decreased shear forces over traditional top round steaks. The addition of commercial beef flavoring (4% solution) to the CaCl(2) and lactic acid injection did not alter the resulting pH, cook loss or total aerobic plate count (APC) of injected steaks. However, beef flavoring did increase the beef/brothy and oniony aromatics and salt taste, and decreased the soured and medicinal aromatics and bitter tastes of hot-boned, CaCl(2) and lactic acid injected top round steaks.

Brachial artery approach for transluminal angioplasty of the internal carotid artery.

One possible problem in internal carotid angioplasty is inaccessibility of the lesion due to elongation of the aortic arch, the brachiocephalic trunk, or the carotid artery itself. A new approach to performing angioplasty of the right or left internal carotid artery utilizing the brachial artery was used after failure of the transfemoral approach in 5 lesions (4 patients). The common carotid artery was cannulated with performed 5F catheters. Angioplasty was performed with a conventional balloon dilatation catheter. If required, a Wall stent was implanted to optimize the angiographic result. After failure of the conventional transfemoral technique, the brachial technique permitted successful angioplasty of the ipsilateral internal carotid artery in 4 lesions and the contralateral internal carotid artery in 1 lesion. In 1 patient, a stent was implanted. No complications occurred. The mean stenosis diameter decreased from 77.8 +/- 6.3% to 17.8 +/- 9.1%. Doppler sonography performed 4-6 months later showed no restenosis. The brachial artery approach seems to be a suitable alternative to the femoral technique.

Organizational empowerment through self-governed teams. An application in long-term care.

In the previous article, Barbara Tebbitt presented a framework for demystifying organizational empowerment. The authors of this manuscript discuss the application of Tebbitt's work in their long-term care facility.

Dental implants placed in a patient with multiple myeloma: report of case.

A 69-year-old male, under active treatment for multiple myeloma, fractured his left maxillary second premolar palatal abutment tooth and requested treatment because his upper partial denture no longer fit. Several other teeth were deemed hopeless, and construction of a maxillary complete denture presented problems. There are general contraindications regarding dental implant surgery in the terminally ill patient; however, in this case, the patient wished to maximize his quality of life and opted to undergo implant surgery. With close management, the treatment was successful.

Empirical models of the electron temperature and density in the nightside venus ionosphere.

Empirical models of the electron temperature and electron density of the late afternoon and nightside Venus ionosphere have been derived from Pioneer Venus measurements acquired between 10 December 1978 and 23 March 1979. The models describe the average ionosphere conditions near 18 degrees N latitude between 150 and 700 kilometers altitude for solar zenith angles of 80 degrees to 180 degrees . The average index of solar flux was 200. A major feature of the density model is the factor of 10 decrease beyond 90 degrees followed by a very gradual decrease between 120 degrees and 180 degrees . The density at 150 degrees is about five times greater than observed by Venera 9 and 10 at solar minimum (solar flux approximately 80), a difference that is probably related to the effects of increased solar activity on the processes that maintain the nightside ionosphere. The nightside electron density profile from the model (above 150 kilometers) can be reproduced theoretically either by transport of 0(+) ions from the dayside or by precipitation of low-energy electrons. The ion transport process would require a horizontal flow velocity of about 300 meters per second, a value that is consistent with other Pioneer Venus observations. Although currently available energetic electron data do not yet permit the role of precipitation to be evaluated quantitatively, this process is clearly involved to some extent in the formation of the nightside ionosphere. Perhaps the most surprising feature of the temperature model is that the electron temperature remains high throughout the nightside ionosphere. These high nocturnal temperatures and the existence of a well-defined nightside ionopause suggest that energetic processes occur across the top of the entire nightside ionosphere, maintaining elevated temperatures. A heat flux of 2 x 10(10) electron volts per square centimeter per second, introduced at the ionopause, is consistent with the average electron temperature profile on the nightside at a solar zenith angle of 140 degrees .

Electron temperatures and densities in the venus ionosphere: pioneer venus orbiter electron temperature probe results.

Altitude profiles of electron temperature and density in the ionosphere of Venus have been obtained by the Pioneer Venus orbiter electron temperatutre probe. Elevated temperatutres observed at times of low solar wind flux exhibit height profiles that are consistent with a model in which less than 5 percent of the solar wind energy is deposited at the ionopause and is conducted downward through an unmagnetized ionosphere to the region below 200 kilomneters where electron cooling to the neutral atmosphere proceeds rapidly. When solar wind fluxes are higher, the electron temperatures and densities are highly structured and the ionopause moves to lower altitudes. The ionopause height in the late afternoon sector observed thus far varies so widely from day to (day that any height variation with solar zenith angle is not apparent in the observations. In the neighborhood of the ionopause, measuremnents of plasma temperatures and densities and magnetic field strength indicate that an induced magnetic barrier plays an important role in the pressure transfer between the solar wind and the ionosphere. The bow, shock is marked by a distinct increase in electron current collected by the instrument, a featutre that provides a convenient identification of the bow shock location.