La doctrina de la sustitucion de la Constitucion colombiana es una creacion jurisprudencial que la Corte Constitucional ha desarrollado para controlar materialmente las reformas constitucionales, pese a que la Constitucion prescribe que el control esta circunscrito a los vicios de formacion en el procedimiento. En este articulo se expone la doctrina, sus antecedentes y las premisas sobre las que se apoya, para luego criticarla. La critica apunta, por una parte, a las inconsistencias teoricas de que adolece, desde una perspectiva logica y juridica; por otra, se dirige al efecto disonante que tiene en el concierto de los poderes estatales, especialmente en relacion con los poderes politicos. La critica subraya lo problematico que resulta la posicion de la Corte Constitucional como arbitro de la politica colombiana, y como esta funcion distorsiona el principio de supremacia constitucional y sofoca el ambito de legitima autonomia de lo politico.

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La doctrina de la sustitución de la Constitución en Colombia

Lab-on-PCB devices have been developed for many biomedical and biochemical applications However, much work has to be done towards commercial applications Even so, the research on devices of this kind is rapidly increasing The reason for this lies in the great potential of lab-on-PCB devices to provide marketable devices This review describes the active flow driving methods for lab-on-PCB devices, while commenting on their main characteristics Among others, the methods described are the typical external impulsion devices, that is, syringe or peristaltic pumps; pressurized microchambers for precise displacement of liquid samples; electrowetting on dielectrics; and electroosmotic and phase-change-based flow driving, to name a few In general, there is not a perfect method because all of them have drawbacks The main problems with regard to marketable devices are the complex fabrication processes, the integration of many materials, the sealing process, and the use of many facilities for the PCB-chips The larger the numbers of integrated sensors and actuators in the PCB-chip, the more complex the fabrication In addition, the flow driving-integrated devices increase that difficulty Moreover, the biological applications are demanding They require transparency, biocompatibility, and specific ambient conditions All the problems have to be solved when trying to reach repetitiveness and reliability, for both the fabrication process and the working of the lab-on-PCB, including the flow driving system

Lab-on-PCB and Flow Driving: A Critical Review

In the development of microfluidics, integration of different materials is becoming critical, especially when the integration of fluidic and electronic components is needed. In this work, a hybrid adhesive bonding method combining adhesive and thermal bonding is proposed. It uses a pressure sensitive adhesive (PSA) tape for integration of a polymethyl methacrylate (PMMA) film and printed circuit board (PCB) substrate while a PMMA microchannel layer is bonded with PMMA film through thermal bonding. The simple bonding process can reliably integrate electronic circuits and fluidic components without any expensive equipment. The relationship between pressure applied during adhesive bonding and the bond ratio is investigated as well as the influence of pressure upon the remaining channel depth during thermocompression. The bond strength is also studied with a dead-end channel test and flow rate test ranging from 20 μl min−1 to 500 μl min−1. The results demonstrate a strong bond formed between the two different layers using the hybrid technique. As an application, a microchip for electrophoresis detection is tested. Successful separation of different ions and a comparable level of the relative standard deviation (RSD) for the migration time and the peak height imply the reliability of the bonding protocol and the good potential for a wide range of applications in the future.

A hybrid adhesive bonding of PMMA and PCB with an application on microchip electrophoresis

Lab-on-chip (LOC) is recognised as one of the most affordable solutions for integrating electronics and fluidics devices. In this field, bonding plays a vital role because it provides the means for attaching multiple components onto a substrate, transforming them into a microfluidic circuit. Bonding is an integral step, especially when designing a device that is free from leakage and eventual clogging. A comprehensive review of the latest irreversible bonding technologies is discussed in this paper, in which the focus is on the layered microfluidic systems with large sensor arrays. This review covers microfluidic devices fabricated from a rigid-type glass–fibre-printed circuit board and a thermoplastic flexible printed circuit with 186 references whose development date back three decades ago. The bonding techniques are organised into the following four groups: (a) adhesive bonding, (b) thermal and solvent bonding, (c) surface modification and dry bonding and (d) photoresist groups. Other techniques are available beyond these groupings, but they can be classified into the nearest group to facilitate the discussion. This paper will benefit researchers and practitioners aiming to develop polymer-based LOC devices.

Irreversible bonding techniques for the fabrication of a leakage-free printed circuit board-based lab-on-chip in microfluidic platforms—a review

This paper describes the fabrication opportunities that Printed Circuit Boards (PCBs) offer for electronic and biomedical engineering. Historically, PCB substrates have been used to support the components of the electronic devices, linking them using copper lines, and providing input and output pads to connect the rest of the system. In addition, this kind of substrate is an emerging material for biomedical engineering thanks to its many interesting characteristics, such as its commercial availability at a low cost with very good tolerance and versatility, due to its multilayer characteristics; that is, the possibility of using several metals and substrate layers. The alternative uses of copper, gold, Flame Retardant 4 (FR4) and silver layers, together with the use of vias, solder masks and a rigid and flexible substrate, are noted. Among other uses, these characteristics have been using to develop many sensors, biosensors and actuators, and PCB-based lab-on chips; for example, deoxyribonucleic acid (DNA) amplification devices for Polymerase Chain Reaction (PCR). In addition, several applications of these devices are going to be noted in this paper, and two tables summarizing the layers’ functions are included in the discussion: the first one for metallic layers, and the second one for the vias, solder mask, flexible and rigid substrate functions.

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Printed Circuit Boards: The Layers’ Functions for Electronic and Biomedical Engineering

Teoría de la constitución como ciencia de la cultura

Fabrication process for inexpensive, biocompatible and transparent PCBs. Application to a flow meter

Fabrication method of lab-on-PCB devices using a microheater with a thermo-mechanical barrier

In this paper, an impulsion system for laboratory on printed circuit board (LOP) is described. The proposed system is intended to place the working liquids in a designed location of the LOP. The system is composed of a pressurization system, a microvalve, and a damping chamber. All these parts have been integrated in a microfluidic system to test the behavior of the whole system. The pressurization system allows the storage of mechanical energy to impulse liquids samples. The microvalve releases the pressure of the commented pressurization system toward the damping chamber. The blast wave effect of the microvalve opening has to be dampened. In this regard, the function of the damping chamber is to reduce the effects of the microvalve activation, resulting in good behavior. The materials used for fabricating the device are polymethylmethacrylate and printed circuit board. These materials and the fabrication process can be considered as mass production. The fabricated devices impulse 32.5 $\mu \text{L}$ during about 24s, and 21.3 $\mu \text{L}$ during 10 s, for the proposed microfluidic configurations. The errors for those impulsions are 5.3% and 6.5%, respectively. Finally, the experimental results and simulations show a good behavior of the system regarding liquid placement and time response. [2017-0293]

Emilio Mikunda Franco

Papers

Teoría de la constitución como ciencia de la cultura

Fabrication process for inexpensive, biocompatible and transparent PCBs. Application to a flow meter

Fabrication method of lab-on-PCB devices using a microheater with a thermo-mechanical barrier

Highly Integrable Microfluidic Impulsion System for Precise Displacement of Liquids on Lab on PCBs

La cultura islámica y los derechos humanos