Miniaturization

In this paper, we present preliminary results showing the response of glucose-sensitive hydrogels, confined in micro-pressure sensors, to the changes in environmental glucose concentration. The glucose concentrations were incrementally varied between 20 and 0mM in 0.15M PBS solution at 7.4 pH and bovine serum at 7.4 pH at room temperature and response of the sensor was recorded. The micro sensors demonstrate a response time of 10 minutes in both PBS and serum. Tissue response after 55 days of subcutaneous implantation of a EtO sterilized sensor in mice is presented. The preliminary analysis of the surrounding tissue shows inflammation which is believed not to interfere with the sensor performance.

In this paper, we present design of a transdermal drug delivery system for treatment of cardiovascular or hemodynamic disorders such as hypertension. The system comprises of integrated control electronics and microelectromechanical system devices such as micropump, micro blood pressure sensor and microneedle array. The objective is to overcome the limitations of oral therapy such as variable absorption profile and the need for frequent dosing, by fabricating a safe, reliable and cost effective transdermal drug delivery system to dispense various pharmacological agents through the skin for treatment of hemodynamic dysfunction such as hypertension. Moreover, design optimization of a piezoelectrically actuated valveless micropump is presented for the drug delivery system. Because of the complexity in analysis of piezoelectric micropump, which involves structural and fluid field couplings in a complicated geometrical arrangement, finite element (FE) numerical simulation rather than an analytical system has been used. The behavior of the piezoelectric actuator with biocompatible polydimethylsiloxane membrane is first studied by conducting piezoelectric analysis. Then the performance of the valveless micropump is analyzed by building a three dimensional electric-solid-fluid model of the micropump. The effect of geometrical dimensions on micropump characteristics and efficiency of nozzle/diffuser elements of a valveless micropump is investigated in the transient analysis using multiple code coupling method. The deformation results of the membrane using multifield code coupling analysis are in good agreement with analytical as well as results of single code coupling analysis of a piezoelectric micropump. The analysis predicts that to enhance the performance of the micropump, diffuser geometrical dimensions such as diffuser length, diffuser neck width and diffuser angle need to be optimized. Micropump flow rate is not strongly affected at low excitation frequencies from 10 to 200 Hz. The excitation voltage is the more dominant factor that affects the flow rate of the micropump as compared with the excitation frequency. However, at extremely high excitation frequencies beyond 8,000 Hz, the flow rate drops as the membrane exhibits multiple bending peaks which is not desirable for fluid flow. Following the extensive numerical analysis, actual fabrication and performance characterization of the micropump is presented. The performance of the micropump is characterized in terms of piezoelectric actuator deflection and micropump flow rate at different operational parameters. The set of multifield simulations and experimental measurement of deflection and flow rate at varying voltage and excitation frequency is a significant advance in the study of the electric-solid-fluid coupled field effects as it allows transient, three dimensional piezoelectric and fluid analysis of the micropump thereby facilitating a more realistic multifield analysis. The results of the present study will also help to conduct relevant strength duration tests of integrated drug delivery device with micropump and microneedle array in future.

The aim of this meta-analysis was to examine the clinical effectiveness of miniscrew implants (MI) used for anchorage reinforcement compared with that of conventional orthodontic means, as well as to assess the success rates of MIs and the possible risk factors affecting their clinical effectiveness. Literature searches were conducted, and, using specific inclusion and exclusion criteria, two independent investigators performed data extraction and analysis. Overall pooled estimates with 95% confidence intervals (CI) were obtained with the random-effects model. Eight out of 3183 original papers met the inclusion criteria. The mean difference of anchorage loss between the MI and conventional anchorage group was −2.4 mm (95% CI = −2.9 mm to −1.8 mm, p = 0). MIs significantly decreased or negated loss of anchorage. Anchorage loss seemed to be less in the mandible, when the MIs were inserted between the second premolar and the first molar, when 2 MIs were inserted per patient jaw, when they were directly connected, as well as when treatment lasted more than 12 months. MIs presented a success rate of 87.7%, with no significant differences between the various subgroups. However, the results of this meta-analysis should be interpreted with some caution because of the number, quality, and heterogeneity
of the included studies.

Dental implant treatment can restore oral function to edentulous patients. Recently, mini implants have been shown to be successful in minimally invasive treatment. There are initial reports of mini implants retaining removable prostheses and supporting fixed partial and complete dentures. This article reviews the treatment of edentulous patients with prostheses and mini implants and offers guidelines for successful outcomes.

The well-acknowledged etch profile drift problem in chip production was investigated with a more accurate means of measuring actual etch thickness to monitor and correct this drift. Using a high-aspect ratio, 0.1m -Si gate structure, the investigation was specifically focused on the control of transition timing in the critical interval from main etch (ME) to over etch (OE). This required reliable endpoint detection of -Si which was achieved through the development of a method employing a Kalman–Bucy filter with a real-time spectroscopic ellipsometer (RTSE). The robustness of our endpoint detection technique was tested and demonstrated under the actual physical and chemical disturbance environments of the etching process. Application of this endpoint detection technique to the etch of a 0.1-m patterned -Si gate also achieved a significant improvement on the etch profile repeatability.

A composite self-excited PZT-glass cantilever (4 mm in length and 2 mm wide) was fabricated and used to measure the binding and unbinding of model proteins. A key feature of the cantilever is that its resonant frequency is dependent on its mass. The fabricated cantilever has mass change sensitivity in liquid of 7.2 × 10−11 g/Hz. Resonant frequency change was measured as protein reacted or bound with the sensing glass cantilever surface. Protein concentrations, 0.1 and 1.0 mg/mL, which resulted in nanogram mass change were successfully detected. The mass change sensitivity gave a total mass change of 54 ± 0.45 ng for the binding of anti-rabbit IgG (biotin conjugated) to rabbit IgG immobilized cantilever and the subsequent binding of captavidin. The unbinding of anti-rabbit IgG and captavidin gave a total mass change of 54 ± 1.70 ng. Fluorescence based assays showed the combined mass of both proteins in the released samples was 54 ± 2.24 ng. The binding kinetics of the model proteins is modeled as first order. The initial binding rate constant of anti-rabbit IgG to rabbit IgG was 1.36 ± 0.02 (min (mg/mL))−1. The initial binding rate constant of captavidin to biotinylated anti-rabbit IgG was (2.57 × 10−1) ± 0.003 (min (mg/mL))−1. The significance of the results we report here is that millimeter-sized PZT-actuated glass cantilevers have the sensitivity to measure in real-time protein–protein binding, and the binding rate constant.

Biotechnology process development involves strain testing and improvement steps aimed at increasing yields and productivity. This necessitates the high-throughput screening of many potential strain candidates, a task currently mainly performed in shake flasks or microtiter plates. However, these methods have some drawbacks, such as the low data density (usually only end-point measurements) and the lack of control over cultivation conditions in standard shake flasks. Microbioreactors can offer the flexibility and controllability of bench-scale reactors and thus deliver results that are more comparable to large-scale fermentations, but with the additional advantages of small size, availability of online cultivation data and the potential for automation. Current microbioreactor technology is analyzed in this review paper, focusing on its industrial applicability, and directions for future research are presented.

Estelle Galbois, « Le colossal et la miniature comme modes d'expression du pouvoir : le portrait royal dans le monde grec antique (IVe-Ier s. avant J.-C.) », dans J.-M. Guillouët et F. Queyrel (coord.), Mini / Maxi : questions d’échelles, Histoire de l'art 77, 2016, p. 7-18.

Résumé

Des études récentes témoignent d’un engouement pour les questions liées à la taille et à l’échelle des productions artistiques et littéraires dans le monde antique. Dans cet article, nous nous proposons de nous intéresser à un aspect particulier de l’imagerie hellénistique : le portrait royal. Après avoir brièvement rappelé l’héritage macédonien et évoqué les discours de Posidippe de Pella, poète à la cour d’Alexandrie au IIIe siècle av. J.-C., sur les œuvres d’art colossales et miniatures, nous évoquerons les formes, les usages et les enjeux des portraits colossaux et des portraits de petites, voire de très petites dimensions, des souverains lagides.

Mots-clés : portrait, colosse, miniature, Lagides, mode de représentation, mise en scène, perception, diffusion, théories des arts

The intrusion of an overerupted maxillary molar using traditional orthodontic treatment is a real challenge. The aim of this study was to investigate the envelope of intrusive movements of a maxillary molar in cases using mini-implants as anchorage with partial or full-mouth fixed edgewise appliances. The cusp tips of the pretreatment and postintrusion dental casts were recorded by a three-dimensional (3D) digitizer. The 3D data of the serial dental casts were analyzed to distinguish the direction and magnitude of individual tooth movement. The mean intrusive movement of the maxillary first molars was three to four mm, with a maximum of over eight mm. For the adjacent maxillary second molars and second premolars, the amount of intrusion was two mm and 1-2 mm, respectively. This study demonstrated that significant true intrusion of maxillary molars could be obtained in a well-controlled manner by using fixed appliances with titanium mini-implants as bony anchorage.

The nineteenth-century ‘panstereorama’ was an urban relief model placed on display as a public spectacle. In this article, I consider first two affiliated forms that help to explain the genre, namely panorama paintings and plans-reliefs. I then go on to consider urban regional practices of city modelling in London and Paris before examining in detail panstereoramas representing Paris and New York. It is argued that this form of model urban cartography served as proxy for the view obtained from the increasingly popular balloon trip and that it accordingly provided virtual travel to, and a map of, the cities depicted.

Free-flow electrophoresis (FFE) separation methods have been developed and investigated for around 50 years and have been applied not only to many types of analytes for various biomedical applications, but also for the separation of inorganic and organic substances. Its continuous sample preparation and mild separation conditions make it also interesting for online monitoring and detection applications. Since 1994 several microfluidic, miniaturized FFE devices were developed and experimentally characterized. In contrast to their large-scale counterparts microfluidic FFE (μ-FFE) devices offer new possibilities due to the very rapid separations within several seconds or below and the requirement for sample volumes in the microliter range. Eventually, these μ-FFE systems might find application in so-called lab-on-a-chip devices for real-time monitoring and separation applications. This review gives detailed information on the results so far published on μ-FFE chips, comprising its four main modes, namely free-flow zone electrophoresis (FFZE), free-flow IEF (FFIEF), free-flow ITP (FFITP), and free-flow field-step electrophoresis (FFFSE). The principles of the different FFE modes and the basic underlying theory are given and discussed with special emphasis on miniaturization. Different designs as well as fabrication methods and applied materials are discussed and evaluated. Furthermore, the separation results shown indicate that similar separation quality with respect to conventional FFE systems, as defined by the resolution and peak capacity, can be achieved with μ-FFE separations when applying much lower electrical voltages. Furthermore, innovations still occur and several approaches for hyphenated, more integrated systems have been proposed so far, some of which are discussed here. This review is intended as an introduction and early compendium for research and development within this field.

Two new, extremely small land snail species, Angustopila coprologos Páll-Gergely, Jochum & Hunyadi n. sp. and Angustopila psammion Páll-Gergely, Vermeulen & Anker n. sp. are described from northern Vietnam and northern Laos, respectively. The former is characterized by a rough surface sculpture and bears tiny mud granules arranged in a pattern of radial lines on its shell surface. The latter species is the new global record-holder of the tiniest land snail title, with a shell width of 0.6–0.68 mm and a shell height of 0.46–0.57 mm. These measurements surpass the former records of Angustopila pallgergelyi and Acmella nana.