Morning surge in sympathetic nervous activity in the indoor environment during the cold winter season.

We addressed to the sympathetic nervous activation of the same people in both their houses and a highly insulated and airtight model house (model house) during the cold winter season. Eight subjects (4 males and 4 females) stayed two nights at each house and were continuously monitored for sympathetic nerve system by calculating LF (low frequency)/HF (high frequency) in the analysis of heart rate variability using a wearable electrocardiography equipment. The room temperatures were kept constant at 20 °C or more in model house, but much lower in their houses. In all subjects, the sleeping duration is longer in model house compared with that in the participants' houses. Four subjects showed a morning surge in sympathetic activity that were more intense at their houses. This morning surge in sympathetic activity in a residential setting suggests the importance of the indoor environment in the management of early morning hypertension.

Temperature dependence of charge separation and recombination in porphyrin oligomer-fullerene donor-acceptor systems.

Electron-transfer reactions are fundamental to many practical devices, but because of their complexity, it is often very difficult to interpret measurements done on the complete device. Therefore, studies of model systems are crucial. Here the rates of charge separation and recombination in donor-acceptor systems consisting of a series of butadiyne-linked porphyrin oligomers (n = 1-4, 6) appended to C(60) were investigated. At room temperature, excitation of the porphyrin oligomer led to fast (5-25 ps) electron transfer to C(60) followed by slower (200-650 ps) recombination. The temperature dependence of the charge-separation reaction revealed a complex process for the longer oligomers, in which a combination of (i) direct charge separation and (ii) migration of excitation energy along the oligomer followed by charge separation explained the observed fluorescence decay kinetics. The energy migration is controlled by the temperature-dependent conformational dynamics of the longer oligomers and thereby limits the quantum yield for charge separation. Charge recombination was also studied as a function of temperature through measurements of femtosecond transient absorption. The temperature dependence of the electron-transfer reactions could be successfully modeled using the Marcus equation through optimization of the electronic coupling (V) and the reorganization energy (λ). For the charge-separation rate, all of the donor-acceptor systems could be successfully described by a common electronic coupling, supporting a model in which energy migration is followed by charge separation. In this respect, the C(60)-appended porphyrin oligomers are suitable model systems for practical charge-separation devices such as bulk-heterojunction solar cells, where conformational disorder strongly influences the electron-transfer reactions and performance of the device.

Single molecule conductance of porphyrin wires with ultralow attenuation.

A series of thioacetate-terminated butadiyne-linked porphyrin oligomers have been synthesized with one to three porphyrin repeat units. Single molecule electrical scanning tunneling microscopy measurements using the I(s) and I(t) methods were used to determine the molecule conductances for this series of oligomers. The molecular conductance shows an exponential falloff with sulfur-sulfur distance with a remarkably low attenuation factor of beta = (0.04 +/- 0.006) A-1.