Orientational effects in the polarized absorption spectra of molecular aggregates.

We present a detailed theoretical analysis of polarized absorption spectra and linear dichroism of cyanine dye aggregates whose unit cells contain two molecules. The studied threadlike ordered system with a molecular exciton delocalized along its axis can be treated as two chains of conventional molecular aggregates, rotated relative to each other at a certain angle around the aggregate axis. Our approach is based on the general formulas for the effective cross section of light absorption by a molecular aggregate and key points of the molecular exciton theory. We have developed a self-consistent theory for describing the orientational effects in the absorption and dichroic spectra of such supramolecular structures with nonplanar unit cell. It is shown that the spectral behavior of such systems exhibits considerable distinctions from that of conventional cyanine dye aggregates. They consist in the strong dependence of the relative intensities of the J- and H-type spectral bands of the aggregate with a nonplanar unit cell on the angles determining the mutual orientations of the transition dipole moments of constituting molecules and the aggregate axis as well as on the polarization direction of incident light. The derived formulas are reduced to the well-known analytical expressions in the particular case of aggregates with one molecule in the unit cell. The calculations performed within the framework of our excitonic theory combined with available vibronic theory allow us to quite reasonably explain the experimental data for the pseudoisocyanine bromide dye aggregate.

Manifestation of the anisotropic properties of the molecular J-aggregate shell in the optical spectra of plexcitonic nanoparticles.

The theoretical studies of light absorption and scattering spectra of the plexcitonic two-layer triangular nanoprisms and three-layer nanospheres are reported. The optical properties of such metal-organic core-shell and core-double-shell nanostructures were previously explained within the framework of pure isotropic models for describing their outer excitonic shell. In this work, we show that the anisotropy of the excitonic shell permittivity can drastically affect the optical spectra of such hybrid nanostructures. This fact is confirmed by directly comparing our theory with some available experimental data, which cannot be treated using conventional isotropic shell models. We have analyzed the influence of the shell anisotropy on the optical spectra and proposed a type of hybrid nanostructure that seems the most convenient for experimental observation of the effects associated with the anisotropy of the excitonic shell. A strong dependence of the anisotropic properties of the J-aggregate shell on the material of the intermediate spacer layer is demonstrated. This allows proposing a new way to effectively control the optical properties of metal-organic nanostructures by selecting the spacer material. Our results extend the understanding of physical effects in optics of plexcitonic nanostructures to more complex systems with the anisotropic and multi-excitonic properties of their molecular aggregate shell.

Patients' views on residual blood use for research purposes.

In order to document patients' views on residual blood use for research purposes, a questionnaire survey was conducted at Aichi Cancer Center Hospital in October 1997. Subjects were patients who had undergone blood tests at a central blood sampling room in the morning during the week of the study enrollment. The questionnaire was handed out and collected at a waiting area in front of the blood sampling room. Of the 583 patients to whom we tried to hand out the questionnaire, 558 participated (258 males, 294 females, and 6 of sex unknown) and 25 refused. Those who regarded research to improve health care as important were 76.7% of those sampled. Only 28 patients (5.0%) answered that they would not permit the use of their residual blood for research purposes. Although logistic analysis did not detect significant factors influencing the giving of permission, the percentage who would not permit the use of their residual blood for research purposes was significantly higher in cancer outpatients (6.7%) than in inpatients (1.0%). It seems desirable for hospitals to establish an open policy concerning residual blood use for research purposes.

Patients' expectations of information provided at cancer hospitals in Japan.

In order to survey patients' views on disease and treatment information that should be provided at hospitals, an anonymous self-administered questionnaire was distributed to patients at Aichi Cancer Center Hospital in 1995. All eligible first-visit outpatients (97 persons), randomly selected revisit outpatients (99 persons; about one in ten refused), and all except six eligible inpatients in good condition at discharge (97 persons) responded. Out of 293 patients (115 males, 174 females and 4 unspecified), 74% answered that they wanted to be informed of their diagnosis irrespective of circumstances, 20% answered that they would want to be informed only in certain circumstances, and 2% did not want to be informed at all. There were no significant differences in response among the three sources of patients. Inpatients wanted more (81%) to be explained about recommended therapy than either first-visit outpatients (67%) or revisit outpatients (67%). The majority considered that about a 30-minute explanation was needed using pamphlet-like written materials or video. When asked what information was needed when choosing a cancer hospital, 71% specified information on the specialty of the hospital, 57% the content of the care provided, 23% the name and specialty of the doctors, 20% the waiting period before scheduled admission, 13% the average admission period, 11% the number of patients with the same disease, 10% the waiting time at the outpatient clinic, 6% the meal menu, and 4% the number of private wards. Forty-three percent wanted an information service covering all hospitals in the region through an information center. The results revealed that patients at this cancer hospital required information on their disease, treatment, and hospital specialty.