A Wireless LC Sensor Coated with Ba0.9Bi0.066TiO3 for Measuring Temperature

This paper presents a passive LC wireless sensor for measuring temperature. The sensor is designed as a parallel connection of a spiral inductor and an interdigitated capacitor and it was fabricated in a conductive layer using LTCC (Low Temperature Co-fired Ceramic) technology. The inderdigitated capacitor electrodes were coated with a thin film of bismuth doped barium titanate (Ba0.9Bi0.066TiO3), whose permittivity changes with temperature, which directly induces changes in the capacitance of the interdigitated capacitor and consequently changes the resonant frequency of the sensor. The measurements of S-parameter of the sensor were performed using a Vector Network Analyzer (E5071B, Agilent Technologies, Santa Clara, CA, USA), whose port was connected to the antenna coil that was placed around the sensor in order to be able to wirelessly detect temperature, in the temperature range from 25 degrees C to 165 degrees C

Effectiveness of Wharton’s jelly stem cells in gastroschisis repair using the inner surface of the umbilical cord as a patch: Long-term results

Objective This retrospective study was designed to assess and compare the anatomical, functional, and esthetic appearance of the umbilical area in patients after repair of gastroschisis using the inner surface of the umbilical cord (UC) and in patients with omphalocele conservatively treated.Background Our procedure transformed gastroschisis into an ‘artificial–surgical omphalocele’ in which the prolapsed intestine was covered with an umbilical patch, the inner surface of which contained Wharton’s jelly (WJ).Methods We have summarized an experience of 17 years in repairing gastroschisis using the inner surface of the UC. From 1986 to 2003, 21 infants with gastroschisis and one with a ruptured omphalocele were treated with this technique. We used Eagle’s medium to prove the validity of the umbilical stump and the duration of its viability. The inner surface of the umbilical patch is a ‘live’ structure with WJ, which contains mucoid connective tissue and fibroblast-like cells – that is, stem cells producing cutis, adipose, and connective tissue.Results Using our method, early control assessment of 18 of 21 patients with gastroschisis, at intervals of 1–3 months, showed good functional and esthetic results. Clinical long-term results in terms of anatomical, clinical, and functional findings were excellent. Besides clinical testimony, we used high-frequency ultrasonography to make an appraisal of the effectiveness of WJ stem cells in the repair of gastroschisis, and compared our results with healthy volunteers and patients with  omphalocele conservatively treated.Conclusion This paper describes the effect of the local application of WJ – that is, mesenchymal stromal cells derived from the inner surface of the umbilical stump – and its influence on the healing process of the birth defect and wound. Keywords: gastroschisis, high frequency ultrasound imaging, inner surface of umbilical patch, ruptured omphalocele, Wharton’s jell

Novel Cost-Effective Microfluidic Chip Based on Hybrid Fabrication and Its Comprehensive Characterization

Microfluidics, one of the most attractive and fastest developed areas of modern science and technology, has found a number of applications in medicine, biology and chemistry. To address advanced designing challenges of the microfluidic devices, the research is mainly focused on development of efficient, low-cost and rapid fabrication technology with the wide range of applications. For the first time, this paper presents fabrication of microfluidic chips using hybrid fabrication technology—a grouping of the PVC (polyvinyl chloride) foils and the LTCC (Low Temperature Co-fired Ceramics) Ceram Tape using a combination of a cost-effective xurography technique and a laser micromachining process. Optical and dielectric properties were determined for the fabricated microfluidic chips. A mechanical characterization of the Ceram Tape, as a middle layer in its non-baked condition, has been performed and Young’s modulus and hardness were determined. The obtained results confirm a good potential of the proposed technology for rapid fabrication of low-cost microfluidic chips with high reliability and reproducibility. The conducted microfluidic tests demonstrated that presented microfluidic chips can resist 3000 times higher flow rates than the chips manufactured using standard xurography technique

TiO2-Based Thick Film pH Sensor

Miniaturized electrochemical pH sensors are increasingly in demand for applications such as online monitoring of water quality and health monitoring. The metal oxides are the best candidates for sensing electrodes of such sensors as they offer high chemical stability. In this paper, we present a novel approach to obtain interdigitated conductimetric pH sensor using screen printing of TiO 2 thick film on an alumina substrate. The microstructural and crystalline properties of the TiO 2 sensitive film were examined with scanning electron microscopy and Raman spectroscopy. The impedance spectroscopic studies of the fabricated thick film sensor were carried out in the frequency range of 5-20 kHz for the test solutions in the pH range of 4-10 and it was observed that the impedance of the film is distinctly dependent on pH. Using the measured impedance data, we have also proposed an equivalent RC network model for the fabricated pH sensor. The physical meaning of the model parameters was determined by electrochemical impedance spectroscopic analysis, and through statistical analysis it was found that all parameters are distinctly pH-dependent

Performance Analysis of Flexible Ink-Jet Printed Humidity Sensors Based on Graphene Oxide

This paper presents design, fabrication, and characterization of flexible capacitive graphene oxide (GO) based humidity sensors, which can be used in many applications, such as environmental protection, civil engineering, and agriculture. They consist of interdigitated electrodes ink-jet printed on a polyimide flexible substrate and GO based sensing layer. Measurement setup for testing and characterization was developed in laboratory conditions. The dependence of the capacitance and resistance of the GO based humidity sensors on the percentage of the applied humidity is presented. The main advantage of developed GO based capacitive humidity sensors is very large variation of capacitance, almost five orders of magnitude, compared with the previously demonstrated sensors. The other advantages of the sensors are fast response-recovery time, excellent reproducibility of the measurement results, and use of cost-effective additive ink-jet technology

Machine Learning Prediction Based Adaptive Duty Cycle MAC Protocol for Solar Energy Harvesting Wireless Sensor Networks

The dynamic nature of energy harvesting rate, arising because of ever changing weather conditions, raises new concerns in energy harvesting based wireless sensor networks (EH-WSNs). Therefore, this drives the development of energy aware EH solutions. Formerly, many Medium Access Control (MAC) protocols have been developed for EH-WSNs. However, optimizing MAC protocol performance by incorporating predicted future energy intake is relatively new in EH-WSNs. Furthermore, existing MAC protocols do not fully harness the high harvested energy to perform aggressively despite the availability of sufficient energy resources. Therefore, a prediction-based adaptive duty cycle (PADC) MAC protocol has been proposed, called PADC-MAC, that incorporates current and future harvested energy information using the mathematical formulation to improve network performance. Furthermore, a machine learning model, namely nonlinear autoregressive (NAR) neural network, is employed that achieves good prediction accuracy under dynamic harvesting scenarios. As a result, it enables the receiver node to perform aggressively better when there is sufficient inflow of incoming harvesting energy. In addition, PADC-MAC uses a self-adaptation technique that reduces energy consumption. The performance of PADC-MAC is evaluated using GreenCastalia in terms of packet delay, network throughput, packet delivery ratio, energy consumption per bit, receiver energy consumption, and total network energy consumption using realistic harvesting data for 96 consecutive hours under dynamic solar harvesting conditions. The simulation results show that PADC-MAC provides lower average packet delay of the highest priority packets and all packets, energy consumption per bit, and total energy consumption by more than 10.7%, 7.8%, 81%, and 76.4%, respectively when compared to three state-of-the-art protocols for EH-WSNs

Defect induced wave-packet dynamics in linear one-dimensional photonic lattices

We study numerically light beam propagation across uniform, linear, one-dimensional photonic lattice possessing one nonlinear defect. Depending on the strength of nonlinear defect, input beam position and phase shift, different dynamical regimes have been identified. We distinguish input parameters set for which a regime of light propagation blockade by the nonlinear defect appears. Obtained results may be useful for all-optical control of transmission of waves in interferometry