<p>Microparticles have been investigated not only as feedstock spherical or amorphous bulk materials used for shape molding, but also as agents that can perform work in the micron scale. The fabrication of microparticles with active properties of self-propulsion, self-assembly, and mobility with enhanced mechanical, thermal, and chemical properties is of particular interest for emerging technologies such as drug delivery, micro-robotics, micro energy generation/harvesting, and MEMS. Conventional fabrication methods can produce several complex particle shapes in one fabrication session or hundreds of spheroid shaped particles per second. Innovative techniques, as flow lithography, have demonstrated control over particle form and composition for continuous fabrication cycles. In recent years predefined shape polymer microparticles have been fabricated as well as ceramic microparticles through suspension processing with these set of techniques. Even though ceramic materials have been fabricated, there is still a strong need to increment the palette of available materials to be processed via flow lithography. We have pioneered the production of shaped ceramic microparticles by Stop-Flow Lithography (SFL) using preceramic polymers, providing control of particle size and shape in the range of 1 – 1000 μm. The principal arranged technique (SFL) combines aspects of PDMS-based microfluidics and photolithography for the continuous cyclable fabrication of microparticles with predefined shapes. The PDMS microchannel devices used were fabricated with vinyl film molds in a laminar hood avoiding the need for a cleanroom, procedure that reduced fabrication costs. After a fabrication session, the preceramic polymer microparticles were collected, washed, and dried before entering an inert atmosphere furnace for pyrolysis. Additionally, by treating the material initially as liquid polymer, special properties can be added by converting it into an emulsion or a suspension. Microparticles were functionalized by introducing porosity and magnetic nanoparticles in the preceramic polymer matrix. The porous characteristic of a particle leads to an increase in surface area, allowing the particle to be infiltrated with a catalyzer or act as a chemical/physical carrier, and the magnetic behavior of the particles allows a controllable trajectory with defined external magnetic fields. These two properties can be used to fabricate bifunctional microparticles to serve as drug carriers through human arteries and veins for drug delivery purposes. We successfully fabricated solid and functional ceramic microparticles in the 10 – 50 μm range with predefined shapes as hexagons, gears, triangles, and ovals. This system is an economical route to fabricate functional defined shape particles that can serve as microrobots to perform tasks in liquid media.</p>

An analysis of the architecture and spatial organization of the Caral-Chupacigarro complex is compared with Pachacamac and other Central Andean prehispanic settlements and also with Çatal Hüyük in Anatolia. It is concluded that the term "settled ceremonial center" describes these sites better than the term "city". The formal diversity of the architectural spaces that make up these early monumental complexes is explained by the ritual activities carried out at them, including banquets, feasts, dances, offerings, sacrifices, etc. The differences in size, volume, and duration of continuous use of buildings in the same complexes, as well as the ceremonial centers, is believe to have no relationship with the number of permanent settlers at them; rather, it is suggested to be directly proportional to the number of regular visitors, and therefore, to the religious and political prestige of these sites. The construction of monumental ceremonial spaces, jointly used by a single community or by an alliance of several communities, and their maintenance and eventual expansion are, in this context, a mechanism for the materialization of the memory of the ritual kinship relations established and periodically legitimized through shared rituals at these localities. / El análisis de la arquitectura y de la organización espacial del complejo Caral-Chupacigarro en comparación con Çatal Hüyük, por un lado, y con Pachacamac y otros asentamientos complejos prehispánicos en los Andes centrales por el otro, lleva al autor a la conclusión de que la expresión "centro ceremonial poblado" describe mejor sus características que el término "ciudad". La diversidad formal de ambientes arquitectónicos de la que se componen los edificios monumentales tempranos se explicaría por las necesidades involucradas en el culto como, por ejemplo, banquetes, ayunos, bailes, ofrendas y sacrificios. Las diferencias en la extensión, volumen construido y duración del uso continuo tanto entre los edificios del mismo complejo como entre diferentes centros ceremoniales no guardan relación proporcional directa con el número de eventuales habitantes permanentes, pero sí con el de la cantidad de visitantes periódicos y, por ende, con su prestigio religioso y político. En este contexto, la construcción del espacio ceremonial y monumental de manera mancomunada por una comunidad o por una alianza de varias comunidades, su mantenimiento y eventuales ampliaciones se constituyen en el mecanismo de materialización de la memoria sobre los lazos de parentesco ritual establecidos por este medio, el que se legitima periódicamente gracias a determinados rituales compartidos.