Abstract: A bendable portion for an endoscope includes a bending mechanism which minimizes the bendable portion diameter and allows a large degree of bending. A bending mechanism embodiment uses a shape memory alloy coil encircling the elastic body of the bendable portion. The shape memory alloy coil is heated to define the shape of the bendable portion.

Abstract: A bendable portion for an endoscope includes a bending mechanism which minimizes the bendable portion diameter and allows a large degree of bending. A first bending mechanism embodiment uses fluid pressure in an axially oriented chamber in a elastic body of the bendable portion. Expansion restraining members are used to restrict the expansion of the bendable portion to only the axial direction, and to protect internal members in the bendable portion. A second bending mechanism embodiment uses a shape memory alloy coil encircling the elastic body of the bendable portion. The shape memory alloy coil is heated to define the shape of the bendable portion.

Abstract: A projection lens system which produces a smaller amount of residual chromatic aberrations and which will exhibit satisfactory performance even if it is used as a long-focus lens. The projection lens system is composed of a front group and a rear group. The front group includes, in order from the object side, a positive first lens element, a positive second lens element and a negative third lens element. The lens system satisfies the following conditions:-0.0015<(.theta.2-.theta.3)/(.nu.2-.nu.3)<0where .theta.2 and .nu.2 denote the dispersion index of the second lens element and .theta.3 and .nu.3 denote the dispersion index of the third lens element, with .theta. and .nu. being defined by:.theta.=(ng-nF)/(nF-nC).nu.=(nd-1)/(nF-nC)where ng, nF, nC and nd denote the refractive indices of a lens element at the g, F, C and d lines, respectively.

Abstract: Porous particles of a calcium phosphate compound having a Ca/P ratio of 1.5 to 1.80, which contain open pores having an average pore size of 100 to 4000 .ANG. and are in the form of spherical particles having an average particle size of 1 to 40 .mu.m, and a process for their production. 90% of the total pore volume of the particles is occupied by pores having a pore size that is 0.5 to 2 times larger than the average pore size of the open pores and the total volume is at least 0.5 ml/g of the particles. The porous calcium phosphate particles are particularly useful as packings for liquid chromatography.

Abstract: A surface treating composition for a reflection preventing film comprising at least one surface treating agent selected from the group consisting of a reactive organic polysiloxane compound containing an amino group and a reactive organic polysiloxane compound containing an epoxy group, and a method for treating a reflection preventing film using such a surface treating composition.