Design and Applications of Minimally Invasive All-Pole Analog Filters

A new design technique for minimally invasive all-pole analog lowpass filters is introduced and the concept of minimally invasive filtering has been generalized for higher orders both in voltage-mode and current-mode operations. The proposed fully differential solution has minimal impact on the in-band signal in terms of added noise and nonlinearity, whereas it has comparable performance for out-of-band signals using smaller number of active devices. Extending the concept of current-mode minimally invasive filters, a novel baseband circuit with third order filtering has been designed, which has comparable linearity and noise with approximately half the power consumption when compared to the conventional solution. The proposed baseband circuit has a bandwidth of 10MHz, achieves 44dB rejection at 50MHz (40dB in post-layout simulations), low broad-band input impedance of 10.16ohm with a comparable noise and linearity at a lower power consumption when compared to a third order conventional circuit. The circuit has been designed in TSMC 130nm technology and is integrated with a broad-band receiver front-end including an LNA and a mixer

Rheological Studies of Injectable Thermoresponsive Biodegradable Hydrogels and Porcine Ocular Tissues

This research has evaluated the rheological properties of two types of materials which include (i) semi-synthetic polymer-based injectable hydrogels [P(NIPAAm-co-DEX-Lactate HEMA) and P(NIPAAm-co-HA-AEMA)], and (ii) biological tissues (porcine ocular tissues). A series of thermoresponsive and biodegradable in situ hydrogel based on N-isopropyacrylamide (NIPAAm) monomer and hydrolytically degradable oligolactate Dextran-lactate-HEMA or Hyaluronic acid (HA)-AEMA macromer were investigated as encapsulation matrices (scaffolds) for DPSCs/ADSCs and assess their applicability in dental/retinal tissue engineering. The rheological properties of the hydrogels were strongly dependent on the reaction conditions and composition of the hydrogels. Both the hydrogels exhibited linear viscoelasticity, and the values of storage moludus (G´) at 1 Hz appeared in the range of 15-35 Pa for P(NIPAAm-co-DEX-Lactate HEMA) gels and 20-40 Pa for P(NIPAAm-co-HA-AEMA) gels at 15 mg·mL-1 concentration. No significant differences were found for the hydrogels prepared with the HA or dextran at the same concentration and monomer to macromer ratio (19:1). The hydrogels were nontoxic to DPSCs and ADSCs at a concentration up to 15 mg·mL-1, and in vitro survival studies using MTT and DAPI indicated that both DPSCs and ADSCs have favorably adhered and proliferated within the dextran and HA-based hydrogels. Survival of the DPSCs/ADSCs in the hydrogels, growth and morphology make these scaffolds a viable option for using as a biological scaffold for tissue engineering. Since the functionality of the ocular tissues closely depends on their biomechanical properties, the rheological properties of the ocular tissues at different stages of development (preterm, neonatal and adult stage) is of therapeutic interest and has not been thoroughly investigated. This study has investigated the shear properties of porcine cornea, sclera and vitreous under strain and frequency sweep. All three tissue types at different stages have shown linear viscoelastic region under strain sweep. The G´ of cornea and vitreous weakly varied between neonatal and preterm, however, the adult cornea (~1.3-fold) and vitreous (~1.8-fold) showed significant higher moduli. On the other hand, the G´ of the sclera increased significantly with the developmental stage of the tissue, (preter

Hierarchical approach for character recognition

This research mainly focuses on recognizing the handwritten character. Several efficient algorithms have been developed by us so far to separate: the handwritten characters from printed text character, the lines, the words, and each character. In this thesis, we concentrate on how to increase the efficiency of recognition of segmented handwritten characters. Certain characters share common features unique to each other, different from the rest of characters. These subsets of characters with common features are then further analyzed by the classifier thereby reducing the number of comparisons that are required. This results increasing the speed of character recognition

Optimizing The Machining Parameters For Minimum Surface Roughness In Turning Al/6% SiC/6%RHA Hybrid Composites

AbstractThis paper discusses the use of the Taguchi experimental design technique to find the optimal parameters while machining Al/6% SiCp/6%RHAp metal matrix hybrid composites. The hybrid composites were fabricated using the stir casting technique. The objective of this work is to investigate the effect of the controllable variables like spindle speed, feed and depth of cut on surface roughness while turning the hybrid composite. Taguchi's L9, orthogonal arrays under different combinations are used for experimentation. The influence of the parameters is also evaluated using signal to noise (S/N) ratio analysis. Optimum parameters which give minimum surface roughness are obtained. S/N plot is drawn and the results are validated using analysis of variance (ANOVA) and the percentage of contribution of each parameter is determined. The scanning electron microscope was used to investigate the worn machined surface of the hybrid composites and the related mechanisms are explained and presented. The 3D surface topography parameter (roughness, skewness, Kurtosis) is also analyzed to predict the worn machined surface of hybrid composites using SPIP software

IL-4 induced MUC4 enhancement in respiratory epithelial cells in vitro is mediated through JAK-3 selective signaling

BACKGROUND: Recent studies have identified MUC4 mucin as a ligand for activation of ErbB2, a receptor tyrosine kinase that modulates epithelial cell proliferation following epithelial damage in airways of asthmatics. In this study, we investigated the potential role of IL-4, one of the Th2 inflammatory cytokines persistent in asthmatic airways, in regulating MUC4 expression using a cell line NCI-H650. METHODS: Real time PCR analysis was performed to determine concentration and time dependent effects of IL-4 upon MUC4 expression. Nuclear run on experiments were carried out to explore potential transcriptional modulation. Western blotting experiments using a monoclonal antibody specific to ASGP-2 domain of MUC4 were performed to analyze MUC4 glycoprotein levels in plasma membrane fractions. To analyze potential signal transduction cascades, IL-4 treated confluent cultures were co-incubated, separately with a pan-JAK inhibitor, a JAK-3 selective inhibitor or a MEK-1, 2 (MAPK) inhibitor at various concentrations before MUC4 transcript analysis. Corresponding transcription factor activation was tested by western blotting using a monoclonal p-STAT-6 antibody. RESULTS: MUC4 levels increased in a concentration and time specific fashion reaching peak expression at 2.5 ng/ml and 8 h. Nuclear run on experiments revealed transcriptional enhancement. Corresponding increases in MUC4 glycoprotein levels were observed in plasma membrane fractions. Pan-JAK inhibitor revealed marked reduction in IL-4 stimulated MUC4 levels and JAK3 selective inhibitor down-regulated MUC4 mRNA expression in a concentration-dependent fashion. In accordance with the above observations, STAT-6 activation was detected within 5 minutes of IL-4 stimulus. No effect in MUC4 levels was observed on using a MAPK inhibitor. CONCLUSION: These observations signify a potential role for IL-4 in MUC4 up-regulation in airway epithelia

Smallholder Farmers’ Perception and Adaptation to Climate Change in Kurmuk District, Ethiopia

Ethiopia is among the countries experiencing frequent drought and highly vulnerable to climate change associated impacts. Adaptation to climate change impacts are key element for sustainable development of economy. The objective of the study was analysis determinates of smallholder farmer’s climate change perception and adaptation options in Kurmuk district. For the study both primary and secondary data sources were employed. The primary data collected from 160 randomly selected sample households. The binary logit and multinomial logit model were employed to identify the factor that determines smallholder farmers’ climate change perception and adaptation strategies respectively.  Results revealed that sex, extension service, credit access, climate information and distance from market are significantly affects smallholder farmers’ perception to climate change in kurmuk district, While, sex, education, cultivated land, access to credit services, climate information, access to market, extension service, distance from farm, off-farm income and on-farm income are found statistically significant affected adaptation options of smallholder farmers. Therefore, strengthening extension services, access credit services, disseminating climate and market information, diversification of farmer’s income are among the recommendable mechanisms to advance their perception and adaptation to climate change

Design and Applications of Minimally Invasive All-Pole Analog Filters

A new design technique for minimally invasive all-pole analog lowpass filters is introduced and the concept of minimally invasive filtering has been generalized for higher orders both in voltage-mode and current-mode operations. The proposed fully differential solution has minimal impact on the in-band signal in terms of added noise and nonlinearity, whereas it has comparable performance for out-of-band signals using smaller number of active devices. Extending the concept of current-mode minimally invasive filters, a novel baseband circuit with third order filtering has been designed, which has comparable linearity and noise with approximately half the power consumption when compared to the conventional solution. The proposed baseband circuit has a bandwidth of 10MHz, achieves 44dB rejection at 50MHz (40dB in post-layout simulations), low broad-band input impedance of 10.16ohm with a comparable noise and linearity at a lower power consumption when compared to a third order conventional circuit. The circuit has been designed in TSMC 130nm technology and is integrated with a broad-band receiver front-end including an LNA and a mixer

Advances in Plasma Arc Welding: A Review

The nature of welding in the aeronautical industry is characterized by low unit production, high unit cost, extreme reliability and severe service conditions. These characteristics point towards more expensive and more concentrated heat sources such as plasma arc, laser beam and electron beam welding as the processes of choice for welding of critical components. Among various precision welding processes, Plasma Arc welding has gained importance in small and medium scale industries manufacturing bellows , diaphragms etc because of less expensive and easy to operate. This paper reviews the works on Plasma Arc welding and associated phenomena such as Micro Plasma Arc Welding, Variable Polarity Plasma Arc welding and Keyhole Plasma Arc Welding. The review covers works carried out by various researchers on various metals using different modes of plasma arc