Development of Devices

The developments of drugs and devices share a common goal of producing products that are safe and effective. However, they differ in the approaches used for product 

---

The development of devices that provide a direct measure of stress or particle velocity led to observations of new rate-dependent mechanical responses and showed the power of such time-resolved measurements. The quartz gauge was the first of these devices with nanosecond time resolution, but its upper operating limit of 4 GPa limited its application. The development of the VISAR has had the most substantial impact on capabilities. VISAR systems, with time-resolution approaching 1 ns and the ability to work to pressures of 100 GPa, provide capabilities that have substantially altered the scientific descriptions of shock-compressed matter. 

The previous chapter outlined how device classification and the use of standards provide the basis for effective regulation of medical devices, with particular focus on the application of design control standards to the development of devices. In this chapter we look at the process for evaluation and authorisation of devices, and see how the regulatory requirements vary depending on the perceived risk of the device as indicated by its classification. It will be noted that there is considerable variation between the approaches adopted in Europe and the US and that, compared to dmgs, practical harmonisation of requirements still remains to be adopted. 

Recently much attention has been directed at the development of devices to control mosquitoes by using products in ambient temperature devices because of their increased safety and ease of use, especially during outdoor activities. This development has resulted in a variety of fan powered mosquito vaporizers and associated formulations which are now being marketed. These devices have limitations in performance that are imposed by the insecticidal activity of the active ingredient used. In order to overcome some of these limitations, we undertook extensive research to find new pyrethroids with higher vapor action which were highly active against mosquitoes. 

Single-centre studies are used where new devices are being developed. For example, the development of devices releasing local anaesthetic or analgesics will require various diverse... 

Among several investigated applications, an interesting one is the development of devices for the microgeneration of power based on a combustion process [35]. 

There are several future trends for the development of passive sampling techniques. The first is the development of devices that can be used to monitor emerging environmental pollutants. Recently, attention has shifted from hydrophobic persistent organic pollutants to compounds with a medium-to-high polarity, for example, polar pesticides, pharmaceuticals, and personal care products.82 147148 Novel materials will need to be tested as selective receiving phases (e.g., ionic liquids, molecularly imprinted polymers, and immunoadsorbents), together with membrane materials that permit the selective diffusion of these chemicals. The sample extraction and preconcentration methods used for these devices will need to be compatible with LC-MS analytical techniques. 

The most welcome technical achievements in life science are the ones that enhance well-being or restore impaired or lost biological functions. Rehabilitation engineering is a research field that has devoted its full spectrum of efforts to compensate for malfunctions and disorders in human biological systems. This includes the development of devices for the rehabilitation of neural disorders which are termed neural prostheses. Neural prostheses directly interface with the central and peripheral nervous system. The most commonly known neural prosthesis is the cardiac pacemaker, which has existed for more than 30 years. A variety of other lesser known devices have been developed to partially restore neural functions in disabled people. 

Chromophores must be thermally robust enough to withstand temperatures encountered in electric field poling and subsequent processing of chromophore/polymer materials. Chromophore decomposition temperatures can be assessed by techniques such as thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA and DSC measurements on neat chromophore samples in air will tend to yield decomposition temperatures lower than those for the same chromophores in hardened polymer lattices. Typically, to be useful for development of device quality materials, a chromophore must exhibit thermal stability of 250 °C or higher (with thermal stability defined as... 

LiNb03 possesses a useful combination of piezoelectric and electro-optical properties that enable the development of devices using visible or near-infrared radiation for the logical processing of information and the routing of channels in telecommunications (see Section 8.3.5). 

In the past five years, many ion conducting polymers and gel electrolytes have been investigated for EDLC application. Figure 15 shows the capacities of various carbon electrodes in SPE or gel electrolytes. The values listed in this figure do not satisfy the requirements for EV. However, it is expected that the requirements of supercapacitors for EV can be achieved by development of devices based on composite electrodes and gel electrolyte systems as described in this chapter. 

In a potentiostatic step experiment on an ultramicrodisc electrode, the current attains a limiting value in a time of the order r ID. In addition to this time scale becoming shorter with decreasing r, the mass transport rate of species to the electrode increases. As a consequence, one motivation for the development of devices using UMEs has been the resulting insensitivity of the limiting current to fluctuations of solution flow rate [62]. Hence UMEs have found widespread use as electrochemical detectors in fluid flow experiments, such as amperometric liquid chromatography (e.g., Ref. [63]) and flow injection analysis (e.g., Ref. [64]). Incidentally, this implies that the current should also be insensitive to vibration. 

There exists a considerable literature on CVD (2) but relatively few attempts have been made to combine chemical and physical rate processes to give a complete representation of the deposition process. Most CVD studies have focused on demonstrating the growth of a particular material or crystal structure. However, the combined analysis is necessary in order to design CVD reactors where it is possible to deposit thin films of constant thickness and uniformity across an entire wafer. This is particularly important in the realization of submicron feature sizes for Very Large Scale Integrated Circuits. The further development of devices based on III-V compounds also depends on CVD reactor design improvements since the composition and thus the electronic properties of these materials vary considerably with process conditions. 

Gastroretentivity of a DF can be achieved by the development of devices that can significantly expand their volume by unfolding or swelling, adhere to intestinal mucosa, or have the suitable density to sink or float over the gastric fluids. 

LSPs are detected as resonance peaks in the absorption or scattering spectra or as dips in the transmission spectra of the metallic nanoparticles. Nanoparticles of very conductive metals like gold, silver, and copper are ideal materials for excitation of localized surface plasmons due to an extremely high ratio of the modulus of the real (Sr) to the imaginary parts (8i) of its dielectric constant. Silver and copper nanoparticles are prone to oxidation and therefore often require coatings of protective over layers. Gold nanoparticles are chemically stable and are employed for the development of devices based on plasmon resonances of nanoparticles. 

Further important technical advances include the development of devices for the automatic scanning of the depolarisation ratio, for measuring Raman CID (circular intensity differentials), for measuring difference Raman spectra (i.e. the difference between the Raman signals from solutions and solvents), for studying optical-fibre Raman spectroscopy, for rapid (i.e. picosecond) Raman spectroscopy and Raman micrography 64). 

Self-regulated insulin device. Because replacement of insulin in diabetic patients by simple injection is not able to prevent the serious consequences of the disease [37], considerable effort is currently being devoted to the development of devices that can release insulin in response to external glucose concentration. 

For this reason, and as already discussed in Sect. 4.2.4, Use of basic excipients, the development of devices that have long erosion times requires the use of a base which will stabilize the interior of a device and only allow erosion to take place in the outer layers from which the base has been depleted by diffusion. Because in early studies we have found that use of water soluble bases such as Na2C03 leads to osmotic imbibing of water with consequent swelling of the device [47], Mg(OH) 2 which has a water-solubility of only 0.8 mg/100 ml was selected. No swelling of devices containing Mg(OH)2 was observed. Thus, this basic salt was used in these studies. 

Recently, the development of devices in which electron energies can be controlled to a reasonable extent has enabled one to discriminate between reactions of these different electronic states. In some favourable cases, the abundances of excited species in primary ion beams are determined fairly accurately as a function of the bombarding electron energy. 

---