Surfactant-loaded capsules as Marangoni microswimmers at the air-water interface: Symmetry breaking and spontaneous propulsion by surfactant diffusion and advection.

We present a realization of a fast interfacial Marangoni microswimmer by a half-spherical alginate capsule at the air-water interface, which diffusively releases water-soluble spreading molecules (weak surfactants such as polyethylene glycol (PEG)), which act as "fuel" by modulating the air-water interfacial tension. For a number of different fuels, we can observe symmetry breaking and spontaneous propulsion although the alginate particle and emission are isotropic. The propulsion mechanism is similar to soap or camphor boats, which are, however, typically asymmetric in shape or emission to select a swimming direction.

From diffusive mass transfer in Stokes flow to low Reynolds number Marangoni boats.

We present a theory for the self-propulsion of symmetric, half-spherical Marangoni boats (soap or camphor boats) at low Reynolds numbers. Propulsion is generated by release (diffusive emission or dissolution) of water-soluble surfactant molecules, which modulate the air-water interfacial tension. Propulsion either requires asymmetric release or spontaneous symmetry breaking by coupling to advection for a perfectly symmetrical swimmer.

Applying circular posterior-hinged craniotomy to malignant cerebral edemas.

Malignant brain edemas are often fatal, regardless of whether they are treated conservatively with sedation, blood pressure management, mannitol-therapy, hyperventilation and hypothermia, or non-conservatively with routine trepanation. Unfortunately, temporal trepanation may result in significant brain damage through herniation of the cerebrum at the edges of the trepanation openings. In one case of a 26-year-old male with severe head injury, a circular posterior-hinged craniotomy (CPHC) was performed after an ineffective unitemporal trepanation for evacuation of an acute subdural hematoma.

[Complications in surgical management of pelvic fractures].

In the care of pelvic injuries complications arise because of organizational and technical factors, some of which are described here. The following measures are important: autotransfusion, emptying the bladder and catheterization, checking and protection of the colon, correct management of the operation table, and prophylactic measures to avoid thrombosis. From an operational/technical point of view, it is most important that a larger with good exposure route be chosen that takes the anatomical structures into account.

[Controlled arched osteotomy for the correction of malposition in healed fractures].

The guided arched osteotomy and the oscillating saws specially developed for this operation have proven to be a competent technique to correct malposition following fractures. Its essential advantage is that the equipment offers the possibility to perform an exact and protective cylindrical cut, which assures exact parallel, relatively large contact areas and hence a favourable postulate for the healing action. Moreover, the saddle-shaped contact area offers protection against unwanted rotation.

[Percutaneous management of intra-articular fractures of the interphalangeal joints of the fingers].

Open reduction of intra-articular fractures of the proximal interphalangeal joints of the fingers requires extensive exposure of the bone. This often leads to disturbance of the delicate mechanics of the joint. The results are, therefore, sometimes not as good as expected.

[Percutaneous management of osseous avulsions of extensor tendons and lateral ligaments of the fingers with the hooked wire].

A new method of percutaneous treatment of some fractures of the fingers is being described. With the use of a magnification table, fitted onto the X-ray intensifier, evulsion fractures of extensor tendons or collateral ligaments can be reduced and fixed by means of a K-wire. After insertion, the end of the wire is being bent in the shape of a hook ("wire hook"), into which a pull-out wire is inserted.

[Pseudarthrosis of the scaphoid].

For the treatment of scaphoid non-unions, innumerable curative and palliative operations have been recommended. Of the curative operations, the various methods of bone grafting give the best results, whereas screw fixation is not satisfactory. Bone pegs with a cortical graft are no longer used because of technical difficulties.

[Partial trisomy 9 with partial retention of the long arm (author's transl)].

A new case of partial trisomy 9 is reported. The characteristic clinical features consist of: 1. Microcephaly, enophthalmos, antimongloid slant of the eyes, hypertelorism, protruding ears, large nose, downward slant of the mouth corners, hypoplasia of phalanges.