4 research outputs found
Motional Feedback in a Bass Loudspeaker: Digital Implementation
No full textThis thesis describes the digital implementation of a motional feedback system for a bass loudspeaker. Motional feedback is used to suppress the linear and non-linear distortions produced by the loudspeaker, especially at the low frequencies. An accelerometer is mounted on the cone of the loudspeaker to provide the feedback signal. The controller which consists of a PI controller and an equalizer are implemented on an FPGA. The equalizer, which is the inverse of the linear model of the loudspeaker, is used to compensate for the linear distortion. The PI controller with negative feedback is used to suppress the non-linear distortion. Not all measurement results are available at the moment of submission of this thesis. However, simulations were carried out on the model of the loudspeakers which show that the linear distortion is fully suppressed. The reduction of the non-linear distortion due to the controller can not be seen in the simulations.Electrical Engineerin
AMMI and GGE biplot analysis of yield of different elite wheat line under terminal heat stress and irrigated environments
No full textWheat crop contributes to a major portion of the agriculture economy of Nepal. It is ranked as the third major cereal crop of the country even though, it faces terminal heat stress which speeds up the grain filling rate and shortens the filling period, causing reduction in grain weight, size, number and quality losses. We can minimize this loss through a genotypic selection of high-yielding lines by understanding the genotype-environment interaction. The objective of this research is to obtain a high yielding line with a stable performance across the environments. In order to do so, we conducted an experiment using eighteen elite wheat lines and two check varieties in alpha-lattice design with two replications in different environments viz. irrigated and terminal heat stress environment from November 2019 to April 2020. The analysis of variance revealed that genotype, environment and their interaction had a highly significant effect on the yield. Furthermore, the which-won–where model indicated specific adaptation of elite lines NL 1179, NL 1420, BL 4407, NL 1368 to the irrigated environment and Bhirkuti to the terminal heat-stressed environment. Similarly, the mean-versus-stability study indicated that elite lines BL 4407, NL 1368, BL 4919, NL 1350, and NL 1420 had above-average yield and higher stability whereas elite lines Gautam, NL 1412, NL 1376, NL 1387, NL 1404, and NL 1381 had below-average yield and lower stability. The ranking of elite lines biplot, PC1 explaining 73.6% and PC2 explaining 26.4% of the interaction effect, showed the rank of elite line, NL 1420 > NL 1368> NL 1350 > other lines, close to the ideal line. On the basis of the obtained results, we recommend NL 1420 with both the high yield and stability is suited across both the environments, while NL 1179 and Bhirkuti is adapted specifically for irrigated and terminal heat stress environment, respectively
Type I Interferon Potentiates IgA Immunity to Respiratory Syncytial Virus Infection During Infancy
Get PDF© 2018, The Author(s). Respiratory syncytial virus (RSV) infection is the most frequent cause of hospitalization in infants and young children worldwide. Although mucosal RSV vaccines can reduce RSV disease burden, little is known about mucosal immune response capabilities in children. Neonatal or adult mice were infected with RSV; a subset of neonatal mice received interferon alpha (IFN-α) (intranasal) prior to RSV infection. B cells, B cell activating factor (BAFF) and IgA were measured by flow cytometry. RSV specific IgA was measured in nasal washes. Nasal associated lymphoid tissue (NALT) and lungs were stained for BAFF and IgA. Herein, we show in a mouse model of RSV infection that IFN-α plays a dual role as an antiviral and immune modulator and age-related differences in IgA production upon RSV infection can be overcome by IFN-α administration. IFN-α administration before RSV infection in neonatal mice increased RSV-specific IgA production in the nasal mucosa and induced expression of the B-cell activating factor BAFF in NALT. These findings are important, as mucosal antibodies at the infection site, and not serum antibodies, have been shown to protect human adults from experimental RSV infection
First-pass perfusion imaging using cardiovascular magnetic resonance in patients with various cardiac implantable electronic devices
No full textMeier C, Bietenbeck M, Theofanidou M, et al. First-pass perfusion imaging using cardiovascular magnetic resonance in patients with various cardiac implantable electronic devices. Clinical Research in Cardiology . 2025.AIMS: The number of patients with cardiac implantable electronic devices (CIEDs) is increasing. However, there is limited experience regarding vasodilator-stress cardiovascular magnetic resonance (CMR) and resulting device artifacts on perfusion images. The aim of this study was to determine CMR image quality in patients with different CIED types for CMR-based perfusion stress testing.; METHODS AND RESULTS: A total of 156 patients with active CIEDs underwent CMR on a 1.5-Tesla scanner. Both conventional steady-state-free-precession (SSFP) and modified spoiled gradient-echo (sGE) protocols under stress and resting conditions were used to evaluate image artifacts in a 16-segment segment model of the heart. The study group comprised 39% conventional pacemaker (PM), 4% cardiac resynchronization therapy-pacemaker (CRT-P), 38% conventional implantable cardioverter-defibrillator (ICD), 6% cardiac resynchronization therapy-ICD (CRT-D), and 13% subcutaneous ICD (S-ICD) patients. PM-carriers showed only minor image artifacts in both perfusion protocols. Artifacts caused by ICDs were predominantly located in the left-ventricular (LV) inferolateral and anterior segments. S-ICDs showed the highest extent of artifacts with an anterolateral accentuation. The artifact extent was significantly reduced when sGE-based perfusion was used compared to SSFP-based sequences. 69% of the patients received a stress-perfusion protocol, and elective coronary angiography confirmed the presence of coronary stenosis in three cases. No major safety-relevant issues occurred.; CONCLUSION: Myocardial perfusion imaging by CMR is safe and feasible with moderate-to-high image quality in patients with all types of CIEDs, including non-conditional devices, ICDs, and S-ICDs. A sGE-based perfusion protocol should be preferred in patients with left-sided ICDs, CRT-Ds, or S-ICDs. © 2025. The Author(s)
