Publisher Summary This chapter discusses the cellular adhesiveness and extracellular substrata. Cell adhesiveness is a fundamental cell property. It plays a role in developmental processes such as cell migration during embryogenesis and morphogenesis in response to particular extracellular matrices; it plays a role in homeostatic processes such as tissue and organ stability, thrombosis, inflammation, and wound healing; and it plays a role in the pathology of various disease states, for instance, in the invasive and metastatic behavior of malignant cells, in disorders of platelet function, and in disorders of leukocyte function. Adhesiveness is common to many different cell types under a variety of conditions, and the underlying mechanisms are analogous for active cell-substratum adhesion occurring in vitro to artificial and to model physiological substrata and in vivo to fibrinogen or fibrin deposits, to the basement membrane, and to other acellular components of the connective tissue.

Cellular adhesiveness and extracellular substrata.

Laboratory demonstrations of spontaneous photoelectrochemical (PEC) solar water splitting cells are reviewed. Reported solar-to-hydrogen (STH) conversion efficiencies range from 10% STH efficiency using potentially less costly materials have been reported. Device stability is a major challenge for the field, as evidenced by lifetimes of less than 24 hours in all but a few reports. No globally accepted protocol for evaluating and certifying STH efficiencies and lifetimes exists. It is our recommendation that a protocol similar to that used by the photovoltaic community be adopted so that future demonstrations of solar PEC water splitting can be compared on equal grounds.

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Experimental demonstrations of spontaneous, solar-driven photoelectrochemical water splitting

Experimental Demonstrations of Spontaneous, Solar-Driven Photoelectrochemical Water Splitting

Photocatalytic decomposition of water at semiconductor electrodes

The efficiency of photoelectrolysis with solar radiation can be greatly enhanced by using simultaneously illuminated n‐ and p‐type electrodes. An energy level scheme for heterotype and homotype p‐n photoelectrolysis cells is presented which explains the enhanced efficiency. Data are presented for the homotype n‐GaP/p‐GaP and the heterotype n‐TiO2/p‐GaP systems which support the energy model. H2 and O2 are produced in the n‐TiO2/p‐GaP cell without the need of an external anodic bias.

p‐n photoelectrolysis cells

FUJISHIMA and Honda1 have described a novel photochemical cell with an open circuit emf of up to 05 V which they indicated had a capability for water photolysis The anode consisted of a TiO2 n-type single crystal which was illuminated by light of wavelength shorter than 415 nm This corresponds to the 30 eV band gap of TiO2 (refs 2–4)

Electricity from photosensitisation of titanium

RECENT publications1,2 report that the mean rotational speed of the Earth's upper atmosphere at altitudes of about 200–400 km is faster than that of the Earth. Rishbeth3 has suggested that an induced electric polarization field at low latitudes plays a part in this “super-rotation”. We offer here an alternative explanation, based on the Scott effect4.

Super-rotation of Upper Atmosphere

PANNELLA1,2 and others3,4 have presented palaeontological counts of the number of days per solar year (N) and per synodic month (n) during geologic time. This method is based on the cyclic growth increments of various fossils and has been confirmed in their modern counterparts1,5. The observations extend back to 1.7 × 109 yr with some incomplete data to 2.8 × 109 yr.

Apparent Loss of Angular Momentum in the Earth–Moon System

Some Observations on the Thermomagnetic Gas-Torque Anomaly

RECENTLY, several new efforts to improve the upper bound on the possible rest mass (m0) of the photon have been made1–3. The theoretical basis is provided by Proca's equations1 (□ + μ2)AK = (4π/c)/JK (1) where charge is assumed conserved and μ = m0c/ħ. The bounds vary from 2 × 10−43 g to 3 × 10−56 g. As Yourgrau and Woodward4 point out, however, a finite mass is implicit in a ‘tired light’ interpretation of the cosmological redshift. When equation (1) is combined with Hubble's law5 dν/dl = −Hν/c (2) it yields μ = H/2c and hence m0 < 10−63 g. Here ν is the photon frequency, l the distance traversed and H is Hubble's constant. In view of this limit a direct demonstration of the existence of a finite photon rest mass does not seem practical at present.

J. Keeney

Papers

Electricity from photosensitisation of titanium

Super-rotation of Upper Atmosphere

Apparent Loss of Angular Momentum in the Earth–Moon System

Some Observations on the Thermomagnetic Gas-Torque Anomaly

Generalisation of Hubble's Law