Efficient Digital Signal Processing Techniques and Architectures for On-Board Processors

In this paper, we present a number of algorithmic and architectural DSP solutions to be incorporated in digital OBPs for communication satellites to boost the system performance primarily in terms of reducing their power consumption. More specifically this article addresses (1) Infinite impulse response (IIR) implementation of digital filters, (2) Efficiency savings in channeliser FFT twiddle storage and multiplications and their reconfigurable implementation (3) Companding of interconnect data, and (4) Critically sampled/reduced over-sampling channelisation. The applicability and efficiency of these approaches were evaluated in detail during our European Space Agency (ESA) funded research project entitled "Efficient Techniques for On-Board Processing”, undertaken by Airbus Defence and Space and the Applied DSP and VLSI Research Group at the University of Westminster. The results demonstrated noteworthy improvements both in terms of power dissipation, and furthermore in the reduction of circuit complexity for future digital OBPs, which will be shown at the summary of results section

On board Processor and Processing Strategies for Next Generation Reconfigurable Satellite Payloads

Today, the increasing demand in higher data rates necessitates new methods as well as higher flexibility for satellite telecommunication payloads in order to address a variety of applications and customers. This paper presents one of these processing strategies that is applicable to today’s processing satellite payloads aiming to meet those demands. For this purpose, a two-tier filter bank is designed as part of a digital onboard processor, which first divides the spectrum at the output of the ADC into a number of sub-bands extracting all the stacked channels in the digital domain. Following the analysis section of the first tier of operations, the extracted channels go under a secondary channelisation process to obtain much finer granularity of 31.25 kHz or 50 kHz depending on the communication standard used for data transmission. The implementation of the channeliser was delivered on a bit-true simulation model and the input and the output of the channelisers were compared and evaluated both in the time and frequency domains

The Design of Low Complexity Low Power Pipelined Short Length Winograd Fourier Transforms

In this paper a novel pipelining approach applicable to Winograd Fourier transforms is presented. The novel approach makes use of reconfigurable multiplier blocks to implement the real multipliers required for the transform as well as sharing the hardware resources among additions. The additions are realized using modified forms of butterfly circuits. The novel approach is tested on a 5-point Winograd Fourier transform and the circuit area and power dissipation of the design are estimated using an in-house power estimation tool and compared to the state-of-the- art approaches

Management and recommendations for the prevention of contrast-induced acute kidney injury. state of the art in clinical practice

Contrast-induced acute kidney injury (CI-AKI) is defined as an acute kidney failure following iodine-based contrast medium administration determining relevant health and socio-sanitary implications. Knowledge of pathophysiology, early diagnosis, and prevention in patients at risk are critical points in CI-AKI management. Determination of risk and functional kidney evaluation must precede every iodine-based contrast medium (CM) administration in order to eventually introduce medical prophylaxis. Furthermore, early laboratoristic evaluation after iodine-based CM exposure should be performed for a prompt identification of acute kidney injury. Therefore, clinicians must know and strictly follow valid recommendations to minimize the development of complications

Ethylene and Chitosan Affected the Seed Yield Components of Onion Depending More on the Dose than Timing of Application

(1) Background: the production of onion seeds is limited by the competition between seeds and the vegetative organs and by scape lodging. However, information on the effects of plant growth regulation on onion seed production is scarce. Aim of the present study was to evaluate the seed yield components and germination ability of onion seeds as affected by the timing and dose of an ethylene application, a plant growth regulator able to modulate shoot–flower competition; and chitosan, an elicitor of plant defense mechanisms able to increase its tolerance to various stresses. (2) Methods: Onion was treated with ethylene at the recommended dose (100% RD) of a commercial product, at 150% RD in two contrasting phenological phases or untreated (control), or ‘with’ or ‘without’ chitosan, and the seed yield components and germination trend were measured. (3) Results: 100% RD at an early phase of growth did not influence the seed yield and increased the thousand seed weight (TSW) by 3.2%. The application of 150% RD decreased the seed yield by 33.5%, and this occurred irrespective of the timing of application. Such decreases were due to a reduction in the number of seeds per flower. The application of chitosan did not affect the crop at 100% RD and increased the seed yield and slightly increased, but not significantly, the TSW under 150% RD. Germination of the fresh seed was 92%, and 17 months of aging reduced it by 14%, with no effects of the treatments on the germination pattern. (4) Conclusions: the ethylene application mostly affected TSW but not the yield, whereas high doses of ethylene reduced yields irrespective of the timing of application. Such a result may have been due to a delay in the flowering onset that occurred in a relatively dry month. Chitosan sustained its yield when the yield potential was reduced by 150% RD, and such a result was likely due to physical protection from the transpiration since the synthetic fungicides applied did not likely allow the pathogens to infections. These results have implications for establishing the timing and dose of application of plant growth regulators and elicitors in seed onions to sustain the seed quality

Impact of IFN lambda 3/4 single nucleotide polymorphisms on the cytomegalovirus reactivation in autologous stem cell transplant patients

Cytomegalovirus (CMV) infection represents one of the main cause mortality after Stem Cell Transplantation. Recently, a protective effect of the T allele of rs12979860 IL28B Single Nucleotide Polymorphisms (SNPs) against CMV infection in the allogenic stem cell transplantation was suggested. We investigate whether the rs12979860 IL28B SNP and the relative rs368234815 (IFNλ4) genotype may affect the incidence of active CMV infection in Autologous stem cell transplantation (Auto-SCT) setting. The study included 99 patients who underwent to Auto-SCT. IL28 and IFNΔ4 SNPs were correlated with CMV reactivation along with other clinical and treatment parameters. CMV reactivation by CMV DNAemia was evaluated once a week until day 100 from Auto-SCT. CMV reactivation was documented in 50% (TT-ΔG/ΔG), 35% (CC-TT/TT) and 29.2% (CT-TT/ΔG) of the patients respectively. No differences in CMV copies number were recorded at reactivation between different IL28/IFNλ4 genotypes. The analysis of patients older than 60 years showed a significantly higher incidence of active CMV infection in the TT-ΔG/ΔG (83%) population with respect to CC-TT/TT (21%) and CT-TT/ΔG (40%) patients. Our data suggest a negative role of TT-ΔG/ΔG genotype in the CMV reactivation in Auto-SCT. The exposure to rituximab and the pre-infusion presence of anti CMV IgG also significantly influenced CMV reactivation

Aluminum modulation of proteolytic activities

The effect of aluminum ions on the activity of proteolyic activities, mainly serine proteases and calpains, has been examined. Aluminum affects the biological activity of proteolytic activities either through a direct effect on the enzyme molecule or through a deregulation of the control mechanisms acting on them. Binding of the ion, most likely results in molecular rearrangements affecting both the substrates binding site and the site involved in the recognition of macromolecular inhibitors. As whole, the data reported clearly indicate that aluminum significatively affects the intracellular protein turnover, most likely triggering catastrophic events for the cellular life. The physiopathological significance of these effects has been discussed, in particular for neurological disorders (the Alzheimer's disease included) where an imbalance of proteolytic as well as antiproteolytic systems appears a crucial event both for the formation of neuritic plaques and neurofibrillary tangles which are the major hallmarks of the disease. © 2002 Elsevier Science B.V. All rights reserved

Influence of bulla volume on postbullectomy outcome

Objective: To quantify the contribution of the resected volume and the presence of associated, functionally significant emphysema to the postoperative improvement of pulmonary function after resection of giant lung bullae. Design: Patients undergoing elective surgery for giant bullae who had complete pulmonary function and radiographic studies performed were reviewed retrospectively. Setting: All 25 patients underwent surgery at the thoracic surgery unit of the University of Pisa, Pisa, Italy. Methods: Pulmonary function was assessed before and 12 months after surgery. On the chest radiograph, the location of bullae, and the signs of compression and emphysema were evaluated. The radiographic total lung capacity (TLCX-ray) and the volume of bullae were measured according to the ellipse method. Postoperatively, functional and radiographic changes were analyzed. The percentage change in forced expiratory volume in 1 s(ΔFEV1%) after surgery was the main outcome measure. The influence of factors related to emphysema and bulla volume on the functional improvement postbullectomy was assessed by stepwise multiple regression. Results: Before surgery, the TLCx-ray overestimated the TLC measured by nitrogen washout, with a mean difference between the two measurements of 1.095 L. A close relationship was found between the TLCx-ray and the plethysmographic TLC (n=6; r=0.95). After surgery, dyspnea lessened (P<0.05) and FEV1 increased (P<0.01). Statistically, the radiographic bulla volume was the single most important factor determining the ΔFEV1% (r=0.80, P<0.0001). Conclusions: These findings suggest that the preoperative size of bullae is the most important contributor to the improvement in ventilatory capacity after bullectomy, and that it is possible to predict the expected increase of postoperative FEV1 from preoperative bulla volume

Adherence in HIV-positive patients treated with single-tablet regimens and multi-pill regimens: findings from the COMPACT study

The use of Combination AntiRetroviral Therapy (cART) has decreased the morbidity and mortality of patients infected with HIV. However, adherence to cART remains crucial to prevent virological failure and disease progression. The aim of this study was to assess adherence to treatment among patients treated with Single Tablet Regimen (STR) or with multi-pill regimens based on Protease Inhibitors (PI), Non-Nucleoside Reverse-Transcriptase Inhibitors (NNRTI), or raltegravir (RAL). An observational retrospective cohort analysis based on administrative and clinical databases was conducted at the National Institute for Infectious Diseases (Rome, Italy). HIV-positive patients treated with a cART between Jan 1st, 2008&#x2013;Dec 31st, 2010 were included. Patients were followed-up for one year since the first prescription during the inclusion period or up to death or switch of at least one drug of the regimen. Adherence and selective non-adherence (days without backbone or 3rd drug) were calculated using pharmacy refill compliance [1]. cART regimens were classified based on number of daily pills (STR vs multi-pill regimen) and on type of third drug. Viral Load (VL) and CD4 cell counts at the end of the follow-up were evaluated. A total of 1,604 patients were analyzed, 70.0% male, age 45.0&#x00B1;8.7, 14.3% newly treated. Patients on STR were 159 (9.9%), PI 878 (54.7%), NNRTI 523 (32.6%), RAL 44 (2.7%). Presence of at least one AIDS-defining conditions (according to Centers for Disease Control classification) was 30% in the STR group, 34% PI, 26% NNRTI, 34% RAL (p=n.s.). Adherence was 80.4&#x00B1;14.7% for STR, 71.8&#x00B1;21.8% PI, 77.1&#x00B1;20.3% NNRTI, 74.0&#x00B1;22.4% RAL. Selective non-adherence was 5.5% (18 days) PI, 2.8% (8 days) NNRTI, 12.5% (43 days) RAL (Figure 1). At the end of the follow-up, VL/CD4 values were available among 709 patients (44%); CD4 count &#x003E;500 cell/mm3 was observed among 61% of patients on STR, 44% PI, 48% NNRTI, 42% RAL and VL &#60; 50 copies/ml was observed among 96% of patients on STR, 78% PI, 88% NNRTI, 87% RAL. Interruptions in cART refill remain a relevant problem across all cART regimens. Patients on STR displayed a higher adherence rate compared to multi-pill regimes (PI, NNRTI, and RAL), primarily due to lack of selective non-adherence. Patients on STR experienced also higher rates of VL &#60; 50 and CD4 &#x003E; 500. The use of an STR regimen appears an effective therapeutic option to avoid selective non-adherence and, consequently, to prevent virological failure and disease progression