Activated Transcription of the Human Neuropeptide Y Gene in Differentiating SH-SY5Y Neuroblastoma Cells Is Dependent on Transcription Factors AP-1, AP-2Α, and NGFI

Activated transcription of the human neuropeptide Y gene ( NPY ) was investigated in SH-SY5Y neuroblastoma cells at the onset of sympathetic neuronal differentiation induced by 12- O -tetradecanoylphorbol 13-acetate (TPA) and serum or by nerve growth factor (NGF). As determined by transient expression, two NGF response elements (REs) were required for transcription induced by NGF in SH-SY5Y cells with stable expression of an exogenous NGF receptor TRK-A gene (SH-SY5Y/trk). TPA treatment in the presence of serum induced NPY transcription in both wild-type SH-SY5Y (SH-SY5Y/wt) and SH-SY5Y/trk cells. A TPA RE (TRE), overlapping the proximal NGF RE, was identified by expression of the v-Jun oncoprotein that enhanced NPY transcription. Suppression of TPA-induced NPY transcription was obtained by expression of a dominant negative Jun protein, selective protein kinase C inhibition, or introduction of a mutated TRE, whereas NGF-induced NPY transcription was inhibited to a lesser degree. The transcription factor AP-2Α was shown to bind cooperatively to the NPY promoter with either AP-1 or NGFI-A to the shared TRE and NGF RE and to the distal NGF RE, respectively. These results show that transcription factors AP-1, AP-2Α, and NGFI-A are involved in activated NPY transcription during the onset of neuronal differentiation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65864/1/j.1471-4159.1998.70051887.x.pd

Trick or Heat? Manipulating Critical Temperature-Based Control Systems Using Rectification Attacks

Temperature sensing and control systems are widely used in the closed-loop control of critical processes such as maintaining the thermal stability of patients, or in alarm systems for detecting temperature-related hazards. However, the security of these systems has yet to be completely explored, leaving potential attack surfaces that can be exploited to take control over critical systems. In this paper we investigate the reliability of temperature-based control systems from a security and safety perspective. We show how unexpected consequences and safety risks can be induced by physical-level attacks on analog temperature sensing components. For instance, we demonstrate that an adversary could remotely manipulate the temperature sensor measurements of an infant incubator to cause potential safety issues, without tampering with the victim system or triggering automatic temperature alarms. This attack exploits the unintended rectification effect that can be induced in operational and instrumentation amplifiers to control the sensor output, tricking the internal control loop of the victim system to heat up or cool down. Furthermore, we show how the exploit of this hardware-level vulnerability could affect different classes of analog sensors that share similar signal conditioning processes. Our experimental results indicate that conventional defenses commonly deployed in these systems are not sufficient to mitigate the threat, so we propose a prototype design of a low-cost anomaly detector for critical applications to ensure the integrity of temperature sensor signals.Comment: Accepted at the ACM Conference on Computer and Communications Security (CCS), 201

Mars Riometer System

A riometer (relative ionospheric opacity meter) measures the intensity of cosmic radio noise at the surface of a planet. When an electromagnetic wave passes through the ionosphere collisions between charged particles (usually electrons) and neutral gases remove energy from the wave. By measuring the received signal intensity at the planet's surface and comparing it to the expected value (the quietday curve) a riometer can deduce the absorption (attenuation) of the trans-ionospheric signal. Thus the absorption measurements provide an indication of ionisation changes occurring in the ionosphere. To avoid the need for orbiting sounders riometers use the cosmic noise background as a signal source. Earth-based systems are not subject to the challenging power, volume and mass restriction that would apply to a riometer for Mars. Some Earth-based riometers utilise phased-array antennas in order to provide an imaging capability

Project Status of the Polish Synchrotron Radiation Facility Solaris

Abstract in Undetermined The Polish synchrotron radiation facility Solaris is being built at the Jagiellonian University in Krakow. The project is based on an identical copy of the 1.5 GeV storage ring being concurrently built for the MAX IV project in Lund, Sweden. A general description of the facility is given together with a status of activities. Unique features associated with Solaris are outlined, such as infrastructure, the injector and operational characteristics

Microelectronics for the thumb-size ultrasound measurement system

This thesis presents building blocks and strategies to reach the goal of a thumb-size autonomous ultrasound measurement system with wireless communication capabilities. The design of modern electronics is based on the possibility to accurately predict system behavior by the use of simulation tools. This paradigm can be extended to components such as sensors attached to the electronics. The ability to simulate mechanical components and electronics together renders possible effective optimization at system level, i.e. minimizing size, cost and power consumption. All of these parameters are important for measurement systems aiming at the rapidly growing field of sensor networking and ambient intelligence. The work in this thesis connects the mechanics of piezoelectric transducers with the design of on-chip microelectronics. Throughout the work, SPICE models of the ultrasound system are used within the design tool for integrated circuits. Improvements and verifications of existing SPICE models for ultrasound equipment is described and applied in the design of integrated electronics for an ultrasound measurement system. The overall aim has been to achieve minimal system size and power consumption through interdisciplinary work based on knowledge within both ultrasonics and electronics. The thesis is divided into introductional chapters and eight attached papers. The introductional chapters give an overview of ultrasound devices, measurement technology, and simulation models. Tools and design flow for analog and mixed signal integrated circuits are discussed. Finally, an overview of the electronics in a pulse-echo ultrasound system is given. The attached papers cover various topics required to reach the goals presented above. The first three papers are closely related to the SPICE models of the piezoelectric devices and the ultrasound propagation media. First, a design strategy towards an area optimized driver stage for piezoelectric crystals with the help of SPICE simulations is presented. A prototype chip design has been made and it is shown that simulations and measured performance agree well. Second, diffraction loss for ultrasound pulses is included in the SPICE models for the ultrasound propagation medium. It is shown that this enables accurate simulations of absolute amplitudes in a pulse-echo ultrasound system with its associated electronics. Third, the influence of parasitic components stemming from cabling in the system are simulated and shown to agree well with measured data. Analog to digital converters and comparators are useful components in a pulse echo ultrasound system. The design of these blocks with focus on low power consumption is presented in two papers. The fourth paper presents a low power, high resolution sigma delta A/D converter, while the fifth paper introduces the deign of a delay-time stable time-continuous comparator suitable for use in time quantization A/D converters. The last three papers address three aspects of system level design of the ultrasound measurement system. The sixth paper presents the mounting of the electronics chip directly onto the piezoelectric crystal using wire bond technology. The setup enables precise pulse control and results in a very compact design. The seventh paper discusses the design of a complete embedded internet system (EIS) confined in the space 25x23x5 mm^3. The system incorporates an integrated web server, Bluetooth communication, and TCP/IP stack and is intended to serve as a base for Internet connected sensors. Finally, the eighth paper introduces a complete on-chip solution for the transmission and reception of ultrasound pulses with a piezoelectric crystal. The chip is designed in a high voltage process, and incorporates an inductive boost pump to achieve a high voltage for the excitation of the crystal. An integrated amplifier is used to amplify incoming pulses. The chip is controlled by a digital state machine used to achieve intermittent operation of the amplifier for minimum power consumption.Godkänd; 2004; 20061025 (haneit

Optimization of a piezoelectric crystal driver stage using system simulations

Using SPICE, successful efforts have previously been made in modeling piezoelectric devices and their functionality. In this paper the piezoelectric device is simulated together with MOS transistor models. The design of a CMOS piezoelectric crystal driver stage is presented. Measurements on a manufactured chip verify the chosen design approach and the performance predicted by the simulations. In the work, achieving small silicon area while maintaining maximum possible output ultrasound pulse amplitude has been a key criterion. The driver stage has been implemented using a 0.6 μm CMOS process. Measurements and simulations have been performed using PZ-27 crystals without backing. Results clearly show that the performance of a complete system comprising both piezoelectric and electronical devices can be predicted with good accuracy using the proposed SPICE simulation approach.Godkänd; 2000; 20061101 (ysko

SPICE modeling of ultrasound systems : improvements and verifications

The success of modern electronics is built on the possibility to accurately predict system behavior by the use of simulation tools. This paradigm can be extended to components such as sensors attached to the electronics. The ability to simulate both sensors (mechanical components) and electronics together renders possible effective optimizations at system level, i.e. minimizing size, cost and power consumption. In this thesis the simulation of a combined electronics and ultrasound sensor system is explored. The environment used is compatible with the electronic simulation tool SPICE. Improvements and verifications of existing SPICE models for ultrasound equipment is described, and applied in the design of integrated analog electronics for an ultrasound measurement system. Emphasis is put on the interdependence between acoustic performance and electronics design. The goal is to improve precision in the simulations to a level where real systems can be implemented from simulation results alone. The thesis is divided into introduction and three attached papers. In the introduction, an overview of ultrasound devices, measurement technology and simulation is given. Tools and design flow for analog integrated circuits are discussed. The first paper shows that system simulations can be used to minimize the size of the transistors used to excite an ultrasound transducer, while keeping maximum output ultrasound energy. A design of an ASIC (Application Specific Integrated Circuit) driver stage for piezoelectric crystals is made and performance of the system is predicted using system simulations. Measurements and simulations are compared, showing that the optimum transistor size can be chosen from simulation data with very good precision. The goal with paper number two is to achieve absolute amplitude correctness in PSpice simulations of ultrasonic systems. Previously published models of the ultrasound propagation medium include viscoelastic loss but disregard loss due to diffraction, i.e. beam spreading. This paper presents a method to include diffraction loss in the models. Measurements and simulations have been performed using a pulse echo system in water. Results show that the simulated amplitude of the returned echo differs less than 10% from measured values in both near and far fields. In paper number three, the influence of parasitic electrical components on measurements and simulations is investigated. It is shown that simulation of excitation pulses can be done with very high accuracy if parasitics are taken into account. The coaxial cable which connects the electronics and the transducer represents one of the major parasitic components in the system. As the cable length is varied, pulse echo amplitudes and time delays shift. It is shown that simulations can be used to predict these effects with good accuracy.Godkänd; 2001; 20070313 (ysko

Incorporation of mechanical noise in the SPICE model of a piezoelectric transducer

SPICE models of a piezoelectric device and the ultrasound propagation medium can be used in a simulator intended for electronic circuits and IC design to make efficient system level optimizations. This paper presents the inclusion of mechanical noise in the SPICE model of an ultrasound system. The modeling of the noise is based on the mechanical thermal noise which is equivalent to electronic Johnson (thermal) noise. For a system with a high-Q piezoelectric device designed into a medium-Q transducer the main energy loss, and thus also the main noise contribution, will occur in backing and sound propagation media. Thus, the modeling of the mechanical noise is performed by including electrical noise generation in the resistors that model these media in the electrical equivalent circuit. The resulting output voltage noise follows theoretical derivations of transducer noise as published by Farlow and Hayward. Simulations of a 4 MHz Pz27 piezoelectric disc with a diameter of 8 mm give a peak spectral noise density over 1 nV / √Hz, which is comparable to that achievable with low-noise preamplifiers.Godkänd; 2008; 20070403 (heering

Energy and pulse control possibilities using ultra-tight integration of electronics and piezoelectric ceramics

This paper reports on investigations of the electrical energy needed to generate ultrasound pulses with piezoelectric crystals and compares measurements with system simulations using SPICE models. The piezoelectric device used is a 16 mm diameter Pz27 crystal with a nominal resonance frequency f/sub oos,nom/ of 4.4 MHz. An optimized ASIC driver stage with 5 V supply voltage is mounted directly on the piezoelectric crystal to generate square-wave excitation pulses. The absence of wiring between driver and crystal provides excellent pulse control possibilities. It is shown that the power consumption varies with the excitation pulse width, which also affects the received ultrasound energy in a pulse echo system. To achieve maximum output ultrasound energy, an excitation pulse width of 100 ns= 0.44/f/sub osc,nom/ should be used. At a repetition rate of 1 kHz, the power consumption including losses in the driver stage varies from 96 /spl mu/W for an excitation pulse width of 240 ns, up to 126 /spl mu/W for an excitation pulse width of 130 ns. The performed SPICE simulations agree well with measured data.Godkänd; 2004; 20060929 (ysko)</p