Optical gap and fundamental gap of oligoynes and carbyne.

The optoelectronic properties of various carbon allotropes and nanomaterials have been well established, while the purely sp-hybridized carbyne remains synthetically inaccessible. Its properties have therefore frequently been extrapolated from those of defined oligomers. Most analyses have, however, focused on the main optical transitions in UV-Vis spectroscopy, neglecting the frequently observed weaker optical bands at significantly lower energies.

The Fritsch-Buttenberg-Wiechell rearrangement: modern applications for an old reaction.

The Fritsch-Buttenberg-Wiechell rearrangement of carbene/carbenoid intermediates has evolved into a valuable synthetic methodology for the preparation of polyyne structures. Various synthetic routes toward the formation of the corresponding precursors, alkynyl-substituted dibromoolefins, have been developed. Additionally, the scope of this methodology is expanded significantly by the development of functional group-tolerant one-pot procedures.

Synthesis of tri- and tetraynes using a butadiynyl synthon.

Using a one-pot protocol, triynes and tetraynes are formed from the reaction of a dibromovinyl triflate and a terminal alkyne under palladium-catalyzed cross-coupling conditions.

Synthesis of diacetylene-containing peptide building blocks and amphiphiles, their self-assembly and topochemical polymerization in organic solvents.

A series of functional iodoacetylenes was prepared and converted into the corresponding diacetylene-substituted amino acids and peptides via Pd/Cu-promoted sp-sp carbon cross-coupling reactions. The unsymmetrically substituted diacetylenes can be incorporated into oligopeptides without a change in the oligopeptide strand's directionality. Thus, a series of oligopeptide-based, amphiphilic diacetylene model compounds was synthesized, and their self-organization as well as their UV-induced topochemical polymerizability was investigated in comparison to related polymer-substituted macromonomers.

Consecutive conformational transitions and deaggregation of multiple-helical poly(diacetylene)s.

The polymerization of diacetylene macromonomers based on oligopeptide-polymer conjugates yields conjugated polymers with multiple-helical quaternary structures. These polymers exhibit a rich dynamic folding behavior upon the addition of protic cosolvents. Thus, a helix-helix transition under helix-sense inversion was followed by a reversible helix-coil transition.

A general concept for the preparation of hierarchically structured pi-conjugated polymers.

Typical biopolymers exhibit structures and order on different length scales. By contrast, the number of synthetic polymers with a similar degree of hierarchical structure formation is still limited. Starting from recent investigations on the structures of amyloid proteins as well as research activities toward nanoscopic scaffolds from synthetic oligopeptides and their polymer conjugates, a general strategy toward hierarchically structured pi-conjugated polymers can be developed.

Functional, hierarchically structured poly(diacetylene)s via supramolecular self-assembly.

The supramolecular self-assembly of macromonomers may serve as a first step to prepare well-defined, highly functionalized, hierarchically structured, conjugated polymers. Functional diacetylene macromonomers equipped with an oligopeptide segment designed to promote self-assembly into parallel beta-sheet type structures and a polydisperse, aliphatic coil segment to prevent global ordering give rise to supramolecular polymers with a tubular double-helical quarternary structure in organic solution. These supramolecular polymers may then be converted into the corresponding poly(diacetylene)s by UV irradiation under retention of their hierarchical structure.

Medical technology management: from planning to application.

Appropriate deployment of technological innovation contributes to improvement in the quality of healthcare delivered, the containment of cost, and access to the healthcare system. Hospitals have been allocating a significant portion of their resources to procuring and managing capital assets; they are continuously faced with demands for new medical equipment and are asked to manage existing inventory for which they are not well prepared. To objectively manage their investment, hospitals are developing medical technology management programs that need pertinent information and planning methodology for integrating new equipment into existing operations as well as for optimizing costs of ownership of all equipment.

Risk assessment - hospital view in selecting medical technology.

Appropriate deployment of technological innovation contributes to improvement in the quality of healthcare delivered, the containment of cost, and access to the healthcare system. Hospitals have been allocating a significant portion of their resources to procuring and managing capital assets; they are continuously faced with demands for new medical equipment and are asked to manage existing inventory for which they are not well prepared. To objectively direct their investment, hospitals are developing medical technology management programs that need pertinent information and planning methodology for integrating new equipment into existing operations as well as for mitigating patient safety issues and costs of ownership.

Percutaneous (nonsurgical) supported angioplasty in unprotected left main disease and severe left ventricular dysfunction.

A 69-year-old patient with the equivalent of severe, unprotected left main coronary artery disease associated with marked left ventricular dysfunction with ventricular aneurysm who had Class IV angina, underwent supported angioplasty utilizing a total percutaneous approach. The patient tolerated occlusion of his main left coronary artery for a total of 7 minutes without difficulty, during dilatation of left anterior descending and two circumflex lesions. He was discharged the following day, symptom free.

Left ventricular pseudoaneurysm secondary to infection after coronary bypass surgery.

We present a case of left ventricular pseudoaneurysm following coronary bypass surgery. The cause was infection, dating from the bypass procedure 1 1/2 years before. Repair of pseudoaneurysm in a patient with a bypass is complicated by the presence of grafts which should be protected from injury.

Myocardial revascularization in patients with chronic renal failure.

Symptomatic coronary artery disease in patients with chronic renal failure can complicate their management in a dialysis program. Hypotension associated with hemodialysis and the anemia of chronic renal disease can produce anginal episodes refractory to medical management. Untreated coronary artery disease may be a contraindication to renal transplantation in an otherwise acceptable candidate.

Spontaneous closure of residual ventricular septal defect following surgical repair of ventricular septal defect complicating acute myocardial infarction.

Spontaneous closure of ventricular septal defects in patients with congenital heart disease is well documented. Also, successful closure of ventricular septal defects complicating myocardial infarction performed in the acute phase have been reported, although the mortality rate is high. Intra-aortic balloon pumping has been helpful in this regard, as it was in our patient.

Bypass of the right and circumflex coronary arteries with the internal mammary artery.

Our experience with the internal mammary artery (IMA) for coronary bypass grafting in the past 3 years includes 323 grafts in 253 patients. After an initial group of IMA to left anterior descending (LAD) coronary artery grafts, we began using the IMA to bypass circumflex and small right coronary arteries (RCA). This report describes our experience with IMA bypass of coronary vessels other than the LAD.

The rechargeable cardiac pacemaker. A clinical evaluation in 25 patients.

After five years of laboratory development and in vivo testing, a rechargeable cardiac pacemaker with R-wave inhibited demand circuitry was introduced into clinical use in February 1973. We have used the rechargeable pacemaker in 25 patients in the past 1 1/2 years. The series includes 14 women and 11 men, with an age range of 38 to 80 years.

Objective elaluation of bypass surgery in patients with acute coronary artery disease.

80 patients with acute coronary artery disease, including 70 patients with PIA, 8 patients with acute myocardial infarction, and 2 patients with cardiogenic shock, underwent bypass surgery. The surgical mortality rate was 1.4% in patients with PIA and during an average follow-up period of 15 months none of the patients died of cardiac disease.