223 research outputs found
Software Implementation of Orthogonal Frequency Division Multiplexing (OFDM)Scheme for Mobile Radio Channel
Orthogonal Frequency Division Multiplexing (OFDM) is a transmission technique which ensures efficient utilization of the spectrum by allowing overlap of carriers. OFDM is a combination of modulation and multiplexing that is used in the transmission of information and data. Compared with the other wireless transmission techniques like Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), OFDM has numerous advantages like high spectral density, its robustness to channel fading, its ability to overcome several radio impairment factors such as effect of AWGN, impulse noise, multipath fading, etc. Due to this it finds wide application in Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB), and Wireless LAN. Most of the wireless LAN standards like IEEE 802.11a or IEEE 802.11g use the OFDM as the main multiplexing scheme for better use of spectrum. In fact in the 4G telecommunication system OFDMA is the backbone of it.
This project deals with the software simulation of this OFDM system in a mobile radio channel using the software tools of MATLAB® and SIMULINK®. From this simulation the performance of OFDM system in mobile radio channel is studied. Apart from this we also compare the OFDM system performance with the performance of the DS-CDMA system in the mobile radio channel
NUMERICAL INVESTIGATION OF THE INFLUENCE OF THE LINK POSITIONING IN THE CORONARY STENT INSIDE THE NORMAL ARTERY: A COMPARATIVE STUDY OF TWO COMMERCIAL STENT DESIGNS
This paper investigates the performance of two commercial stent designs inside the normal artery for induced Von Mises Stress and radial displacement pattern. Investigation focuses on identifying the key design feature of the stent structure responsible for varied stress and displacement pattern. Two commercial stent designs, Supraflex (Stent S) and Yukon Choice (Stent T),are modeled using micro CT images and MIMICS® while idealized models are used for investigation. ANSYS Workbench is used to numerically expand the stent inside an idealized normal artery with inflation pressure. The stent and the artery are modeled using elastic-plastic and hyperelastic material models, respectively. The results suggest crucial influence of the link positioning in inducing an area of higher Von Mises Stress and stress gradient. The locations of a higher stress gradient are those in line with unbound stent crowns. Also, higher and uniform arterial displacement can be observed in the locations in line with the bound crown. Results also suggested a considerable difference in arterial distortion induced by two designs, causes for which can also be attributed to the differences in the link placement. The study suggests that the link connections play a crucial role in setting up stress field/radial displacement. Suitable modification of the link positioning can reduce the higher stress gradient and arterial distortion, which probably can reduce arterial injury
Tracheobronchial adenoid cystic carcinoma treated with radical radiochemotherapy: Case report and review of literature
Adenoid cystic carcinoma (ACC) is a low-grade malignancy of the elderly but has shown aggressive behavior. It is most commonly found in minor salivary glands and rarely in lacrimal glands, tracheobronchial tree, lung parenchyma, breast, cervix, skin, esophagus, prostate. The standard of care of ACC is essentially surgery followed by post-operative adjuvant radiation therapy depending upon various adverse features. Here we report an unusual tracheo-bronchial ACC in a 32-year-old lady who was treated with radical radiotherapy under image guidance along with concurrent chemotherapy using intravenous cisplatin on weekly basis. Response evaluation with 18FDG PET-CECT three months after the completion of treatment showed complete response, and has also remained disease free clinically at 3 years follow-up, without any late radiation toxicity
Agroforestry practices for physiological amelioration of salt aff ected soils
Agroforestry is a sustainable land use system act as an alternative form of biological reclamation in salt affected soils apart from sustainable production, continuous income, and regular employment along with food and nutrition security. In general, salt affected soils get ameliorated by tree species; however, following factors such as nature and type of tree species planted, growth habit, quantity and quality of litter production, planting density, nitrogen fixation, and different management practices are influenced. In the present study, various studies pertaining to soil reclamation in the salt affected soils are reviewed. Overall result showed that trees grown with crops, horticultural crops, pastures resulted in improvement of physical and chemical properties of soil under various agroforestry systems. For instance, reduction of soil pH, electrical conductivity, and exchangeable sodium percentage minimization of salt deposition in the upper layers of the soil, improvement of water permeability and water holding capacity, improvement of infiltration rate and hydraulic conductivity with soil fertility, enhancement of cation exchange capacity, and other features are characteristics of soil as influenced by tree species, as well as through agroforestry practices. Various multipurpose tree species such as Acacia auriculiformis, Acacia nilotica, Albizia lebbeck, Terminalia arjuna, Casuarina equisetifolia, Prosopis cineraria, Prosopis juliflora; and fruit trees such as Zizyphus jujuba, Emblica officinalis, Syzygium cumini, and Tamarindus indica ameliorated the different salt affected soils in different agroforestry systems viz., agrisilvicultural system, silvipastoral system, multipurpose wood lot, and agrihorisilvicultural system. Thus, agroforestry system provides an alternative for restoring soil health and amelioration of salt affected soils for further yield improvement. Therefore, these species are suggested for reclamation of salt affected soil through agroforestry systems
Process Study of Joda East Washing Plant, Tata Steel
Tata Steel is planning for 7.0 mtpa of crude steel product-ion from the present level of 4 mtpa.Accordingly, the iron ore requirement will also increase significantly. More-over, to increase the blast furnace productivity, signifi-cant improvement in the quality of the iron ore is requi-red. To meet a parts of this enhanced requirement of iron ore, both in terms of quantity and quality, a process audit study was undertaken at Joda Iron ore washing plant. The objectives of the study was to assess the process capabilities and to identify the gap areas for a) improv-ing product quality with respect to A1203 content, size distribution, and b) increasing plant throughput. The studies were carried out at three different ore ratios. The performance of the various unit operations and ore ratios on beneficiation products are discussed in this
paper
Metal nanoparticle alters adenine induced charge transfer kinetics of vitamin K3 in magnetic field
In this article, we highlight the alterations in the photoinduced electron transfer (ET) and hydrogen atom transfer (HAT) pathways between an anti-tumor drug vitamin-K3 (MQ) and a nucleobase adenine (ADN) in the presence of gold (Au) and iron (Fe) nanoparticles (NPs). Inside the confined micellar media, with laser flash photolysis corroborated with an external magnetic field (MF), we have detected the transient geminate radicals of MQ and ADN, photo-generated through ET and HAT. We observe that the presence of AuNP on the MQ-ADN complex (^(Au)MQ-ADN) assists HAT by limiting the ET channel, on the other hand, FeNP on the MQ-ADN complex (^(Fe)MQ-ADN) mostly favors a facile PET. We hypothesize that through selective interactions of the ADN molecules with AuNP and MQ molecules with FeNP, a preferential HAT and PET process is eased. The enhanced HAT and PET have been confirmed by the escape yields of radical intermediates by time-resolved transient absorption spectroscopy in the presence of MF
Cytoprotective Activated Protein C Averts Nlrp3 Inflammasome–Induced Ischemia-Reperfusion Injury Via Mtorc1 Inhibition
Cytoprotection by activated protein C (aPC) after ischemia-reperfusion injury (IRI) is associated with apoptosis inhibition. However, IRI is hallmarked by inflammation, and hence, cell-death forms disjunct from immunologically silent apoptosis are, in theory, more likely to be relevant. Because pyroptosis (ie, cell death resulting from inflammasome activation) is typically observed in IRI, we speculated that aPC ameliorates IRI by inhibiting inflammasome activation. Here we analyzed the impact of aPC on inflammasome activity in myocardial and renal IRIs. aPC treatment before or after myocardial IRI reduced infarct size and Nlrp3 inflammasome activation in mice. Kinetic in vivo analyses revealed that Nlrp3 inflammasome activation preceded myocardial injury and apoptosis, corroborating a pathogenic role of the Nlrp3 inflammasome. The constitutively active Nlrp3A350V mutation abolished the protective effect of aPC, demonstrating that Nlrp3 suppression is required for aPC-mediated protection from IRI. In vitro aPC inhibited inflammasome activation in macrophages, cardiomyocytes, and cardiac fibroblasts via proteinase-activated receptor 1 (PAR-1) and mammalian target of rapamycin complex 1 (mTORC1) signaling. Accordingly, inhibiting PAR-1 signaling, but not the anticoagulant properties of aPC, abolished the ability of aPC to restrict Nlrp3 inflammasome activity and tissue damage in myocardial IRI. Targeting biased PAR-1 signaling via parmodulin-2 restricted mTORC1 and Nlrp3 inflammasome activation and limited myocardial IRI as efficiently as aPC. The relevance of aPC-mediated Nlrp3 inflammasome suppression after IRI was corroborated in renal IRI, where the tissue protective effect of aPC was likewise dependent on Nlrp3 inflammasome suppression. These studies reveal that aPC protects from IRI by restricting mTORC1-dependent inflammasome activation and that mimicking biased aPC PAR-1 signaling using parmodulins may be a feasible therapeutic approach to combat IRI
Stranding of dolphins along north Andhra Pradesh coast
On 6th November 2021, a Risso’s
Dolphin, Grampus griseus (G. Cuvier,
1812) which measured as 230 cm
in total length was stranded on the
Rushikonda beach, Visakhapatnam.
Reported stranding of this species
from coast of Andhra Pradesh is rare
- …