Radimir Vrba

Integrated smart sensor networking framework for sensor-based appliances

This paper presents an integrated, sensor networking framework stemming from the IEEE 1451 smart transducer interface standard. This object-based networking model is complemented by the Virtual Interface Architecture (VIA), a Compaq-Intel-Microsoft approach to Internet messaging, and by the Internet Protocol (IP) multicast communication, mediating efficient and unified access from Internet to smart sensors. An application of networked sensors that offers a reusable design pattern for a class of sensor-based appliances is analyzed. The kernel of the paper focuses utilization of this framework for a computer-based pressure measurement systems developing environment as a real-world project while stressing smart pressure sensor and Internet connectivity architectures.

Executable specifications for embedded distributed systems

Combining hardware components with an executable specification language facilitates the specification prototyping of embedded distributed systems. The specification language should cover process management, timing, and communication commands that real-time executive and communication task services of every node prototype can interpret. We use a technique that employs attribute grammars and either a macro processor or Prolog to execute the language.

Bio-sensing of cadmium(II) ions using Staphylococcus aureus.

Cadmium, as a hazardous pollutant commonly present in the living environment, represents an important risk to human health due to its undesirable effects (oxidative stress, changes in activities of many enzymes, interactions with biomolecules including DNA and RNA) and consequent potential risk, making its detection very important. New and unique technological and biotechnological approaches for solving this problems are intensely sought. In this study, we used the commonly occurring potential pathogenic microorganism Staphylococcus aureus for the determination of markers which could be used for sensing of cadmium(II) ions. We were focused on monitoring the effects of different cadmium(II) ion concentrations (0, 1.25, 2.5, 5, 10, 15, 25 and 50 μg mL−1) on the growth and energetic metabolism of Staphylococcus aureus. Highly significant changes have been detected in the metabolism of thiol compounds—specifically the protein metallothionein (0.79–26.82 mmol/mg of protein), the enzyme glutathione S-transferase (190–5,827 μmol/min/mg of protein), and sulfhydryl groups (9.6–274.3 μmol cysteine/mg of protein). The ratio of reduced and oxidized glutathione indicated marked oxidative stress. In addition, dramatic changes in urease activity, which is connected with resistance of bacteria, were determined. Further, the effects of cadmium(II) ions on the metabolic pathways of arginine, β-glucosidase, phosphatase, N-acetyl β-d-glucosamine, sucrose, trehalose, mannitol, maltose, lactose, fructose and total proteins were demonstrated. A metabolomic profile of Staphylococcus aureus under cadmium(II) ion treatment conditions was completed seeking data about the possibility of cadmium(II) ion accumulation in cells. The results demonstrate potential in the application of microorganisms as modern biosensor systems based on biological components.

New Role for L-Arginine in Regulation of Inducible Nitric-Oxide-Synthase-Derived Superoxide Anion Production in Raw 264.7 Macrophages

Dietary supplementation with L-arginine was shown to improve immune responses in various inflammatory models. However, the molecular mechanisms underlying L-arginine effects on immune cells remain unrecognized. Herein, we tested the hypothesis that a limitation of L-arginine could lead to the uncoupled state of murine macrophage inducible nitric oxide synthase and, therefore, increase inducible nitric-oxide-synthase-derived superoxide anion formation. Importantly, we demonstrated that L-arginine dose- and time dependently potentiated superoxide anion production in bacterial endotoxin-stimulated macrophages, although it did not influence NADPH oxidase expression and activity. Detailed analysis of macrophage activation showed the time dependence between LPS-induced iNOS expression and increased O2∙− formation. Moreover, downregulation of macrophage iNOS expression, as well as the inhibition of iNOS activity by NOS inhibitors, unveiled an important role of this enzyme in controlling O2∙− and peroxynitrite formation during macrophage stimulation. In conclusion, our data demonstrated that simultaneous induction of NADPH oxidase, together with the iNOS enzyme, can result in the uncoupled state of iNOS resulting in the production of functionally important levels of O2∙− soon after macrophage activation with LPS. Moreover, we demonstrated, for the first time that increased concentrations of L-arginine further potentiate iNOS-dependent O2∙− formation in inflammatory macrophages.

New CMOS potentiostat as ASIC for several electrochemical microsensors construction

Purpose – The purpose of this paper is to design and create a potentiostat that can be integrated and encapsulated within a microelectrode as a low‐cost electrochemical sensor. Recently, microsystems on sensors or lab on a chip using electrochemical detection of substances matters are pushing forward into the area of analysis. For providing electrochemical analysis, the microsystem has to be equipped with an integrated potentiostat.Design/methodology/approach – The integrated potentiostat with four current ranges (from 1 μA to 1 mA) was designed in the CADENCE software environment using the AMIS CMOS 0.7 μm technology and fabricated under the Europractice program. Memory cells of 48 bytes are implemented with the potentiostat using VERILOG.Findings – The characteristics of integrated potentiostat are strictly linear; the measured results confirm the simulated values. The potentiostat measurements error is about 1.5 percent and very low offsets are reached by the offset‐zeroing circuitry.Research limitatio...

MEMS Carbon Nanotubes Field Emission Pressure Sensor With Simplified Design: Performance and Field Emission Properties Study

The pressure sensor application gained recently substantial interest in many fields of basic and applied research and applications. In this paper, microelectromechanical system (MEMS)-based pressure sensor contains nanostructured electrode consisting of carbon nanotube (CNT) array. CNTs are directly grown on such electrode by plasma-enhanced chemical vapor deposition method using microwave plasma torch at atmospheric pressure. This growth method enables us to use a simple electrode structure without need of buffer layer and time-consuming lithography process. Combination of CNTs field emission and MEMS membrane mechanical properties make possible to enhance sensitivity of the sensor. Field emission properties of CNTs are measured by newly developed system enabling us precise measurement of expecting properties, such as dependence on diaphragm (upper electrode) distance, applied voltage, and stability of the sensor. Measured values are compared with a numerical modeling of the membrane system in CoventorWare software by finite-element method. We also suggest encapsulating the sensor using glass frit bonding because such method is more suitable for high vacuum requirements of the field emission operation.

Wireless temperature data logger

Knowledge of temperature course during a certain time is needed in scientific, medical and industrial applications. In some applications, however, the recorded temperature course should be read wirelessly. This paper describes main principles applied in a set of mobile temperature data logger and portable reader/writer with wireless transfer of digitized temperature values. A mobile temperature data logger with RFID features was designed for applications, where portability and wireless data transfer is inevitable. Communicating reader/writer can be mounted on the wall or can be portable, too. Two main modes of operation during temperature data logging may be remotely chosen for a tag. Mode 1 - standard storing of data in preprogrammed regular acquisition time intervals (100 milliseconds up to 2 hours) with number of samples limited only by a data EEPROM memory size. Mode 2 - more memory size reducing method, when only breaking lower and upper temperature limits initiates storing the date and time stamp. However, the following date and time stamp is stored only when the temperature returns back into the temperature band between lower and upper temperature predefined limits. This mode 2 corresponds with a structure of data stored in data EEPROM memory. Enhanced mode can be set when the maximum or minimum temperature between breaking and returning points of a sampling temperature course is stored, too. This is a typical example for monitoring of food transport, where the time stamp and maximum temperature after breaking the limit are proofs to define the offender who damaged the transported goods.

Wireless communication in automation

The paper shows the challenges associated with attempts to utilize Bluetooth communication interface for automation purposes like control and data acquisition. The paper describes major challenges, selected approach, first tests, first experiences with Bluetooth on Linux. and first prototypes of embedded devices used for testing. Moreover the paper discusses some specific challenges associated with utilization of wireless communication techniques (focused to Bluetooth) in automation. Finally the paper presents ideas (formal methods) that could be used to analyze, and improve reliability of such system, and approach (time triggered approach with clock synchronization) that could be used to improve the deterministicity of wireless communication channels.

An integrated framework for Internet-based applications of smart sensors

This paper presents an application of networked sensors that offers a reusable design pattern for a class of sensor-based appliances. It deals with an integrated, sensor networking framework stemming from the IEEE 1451 smart transducer interface standard, an object-based networking model, complemented by the Virtual Interface Architecture (VIA), a Compaq-Intel-Microsoft approach to Internet messaging, and by the Internet Protocol (IP) multicast communication, mediating efficient and unified access from Internet to smart sensors. The kernel of the paper focuses on utilization of this framework for a computer-based pressure measurement systems development environment as a real-world project while stressing smart pressure sensor and Internet connectivity architectures.

Coupling architectures for low-level fieldbusses

This paper deals with hierarchical, multiple fieldbus-based architectures using four case studies that present some concepts reusable in developing the interconnections of intelligent sensors and actuators. The single-master, low-level fieldbusses considered involve (1) ASI (Actuator-Sensor-Interface), which is an example of a lowest-level industrial interconnection; (2) NBIP (Nine-Bit Inter-processor Protocol), which is an example of a special purpose link-layer protocol for microcontrollers; and (3) Bitbus, which is an example of well-established fieldbus utilized for almost 20 years in various applications. The paper begins with classification issues; particularly, coupling architectures are treated both from the viewpoint of more classical interconnections of wide-area and local-area networks, and from the viewpoint of fieldbus domain. Next part introduces the ASI and NBIP protocols while the well-known Bitbus is reviewed in applications. To offer more complex insight, implementation tools-developed particularly to support low-level fieldbus interconnecting experiments-are also mentioned. Four case studies demonstrating consequently NBIP-ASI, ASI-ASI, and two different Bitbus-NBIP hierarchical coupling structures create the kernel of the paper. Finally, brief notes about origins, results, and current targets of the project conclude the contribution.