234 research outputs found
A MMIC QPSK Modulator
In this paper a MMIC QPSK modulator is described. The bit rate of the baseband signal is 155 Mbits/sec, while the frequency of the carrier is fLO=10âGHz
. The modulation is performed directly at the RF band and therefore an IF
stage is not necessary. The design contains all the necessary sub-circuits except for the demultiplexer and the low-pass filters, which are used so that the bandwidth of the binary waves can be reduced. The mixers that are contained in the circuit are not the typical Gilbert cells and as a result they occupy a much smaller area (half). The circuit needs no external LO coupler and no RF chocks. The F-20 process of GEC Marconi was used for designing the modulator. The occupied area is approximately 12âmm2
. Section 1 presents fundamentals on Quadriphase Shift Keying (QPSK), while in Section 2 the characteristics of the F-20 process are described. In the following Sections the sub-circuits, the complete circuit, and its simulated results are presented
Classification of Event-Related Potentials Associated with Response Errors in Actors and Observers Based on Autoregressive Modeling
Event-Related Potentials (ERPs) provide non-invasive measurements of the electrical activity on the scalp related to the processing of stimuli and preparation of responses by the brain. In this paper an ERP-signal classification method is proposed for discriminating between ERPs of correct and incorrect responses of actors and of observers seeing an actor making such responses. The classification method targeted signals containing error-related negativity (ERN) and error positivity (Pe) components, which are typically associated with error processing in the human brain. Feature extraction consisted of Multivariate Autoregressive modeling combined with the Simulated Annealing technique. The resulting information was subsequently classified by means of an Artificial Neural Network (ANN) using back-propagation algorithm under the âleave-one-out cross-validationâ scenario and the Fuzzy C-Means (FCM) algorithm. The ANN consisted of a multi-layer perceptron (MLP). The approach yielded classification rates of up to 85%, both for the actorsâ correct and incorrect responses and the corresponding ERPs of the observers. The electrodes needed for such classifications were situated mainly at central and frontal areas. Results provide indications that the classification of the ERN is achievable. Furthermore, the availability of the Pe signals, in addition to the ERN, improves the classification, and this is more pronounced for observersâ signals. The proposed ERP-signal classification method provides a promising tool to study error detection and observational-learning mechanisms in performance monitoring and joint-action research, in both healthy and patient populations
Fuel cell systems and traditional technologies. Part II: Experimental study on dynamic behavior of PEMFC in stationary power generation
Microwave beamforming for non-invasive patient-specific hyperthermia treatment of pediatric brain cancer
Evidence Map of Pancreatic SurgeryâA living systematic review with meta-analyses by the International Study Group of Pancreatic Surgery (ISGPS)
Background: Pancreatic surgery is associated with considerable morbidity and, consequently, offers a large and complex field for research. To prioritize relevant future scientific projects, it is of utmost importance to identify existing evidence and uncover research gaps. Thus, the aim of this project was to create a systematic and living Evidence Map of Pancreatic Surgery. Methods: PubMed, the Cochrane Central Register of Controlled Trials, and Web of Science were systematically searched for all randomized controlled trials and systematic reviews on pancreatic surgery. Outcomes from every existing randomized controlled trial were extracted, and trial quality was assessed. Systematic reviews were used to identify an absence of randomized controlled trials. Randomized controlled trials and systematic reviews on identical subjects were grouped according to research topics. A web-based evidence map modeled after a mind map was created to visualize existing evidence. Meta-analyses of specific outcomes of pancreatic surgery were performed for all research topics with more than 3 randomized controlled trials. For partial pancreatoduodenectomy and distal pancreatectomy, pooled benchmarks for outcomes were calculated with a 99% confidence interval. The evidence map undergoes regular updates. Results: Out of 30, 860 articles reviewed, 328 randomized controlled trials on 35, 600 patients and 332 systematic reviews were included and grouped into 76 research topics. Most randomized controlled trials were from Europe (46%) and most systematic reviews were from Asia (51%). A living meta-analysis of 21 out of 76 research topics (28%) was performed and included in the web-based evidence map. Evidence gaps were identified in 11 out of 76 research topics (14%). The benchmark for mortality was 2% (99% confidence interval: 1%â2%) for partial pancreatoduodenectomy and <1% (99% confidence interval: 0%â1%) for distal pancreatectomy. The benchmark for overall complications was 53% (99%confidence interval: 46%â61%) for partial pancreatoduodenectomy and 59% (99% confidence interval: 44%â80%) for distal pancreatectomy. Conclusion: The International Study Group of Pancreatic Surgery Evidence Map of Pancreatic Surgery, which is freely accessible via www.evidencemap.surgery and as a mobile phone app, provides a regularly updated overview of the available literature displayed in an intuitive fashion. Clinical decision making and evidence-based patient information are supported by the primary data provided, as well as by living meta-analyses. Researchers can use the systematic literature search and processed data for their own projects, and funding bodies can base their research priorities on evidence gaps that the map uncovers. © 2021 The Author
PRISMA for abstracts: best practice for reporting abstracts of systematic reviews in Endodontology
An abstract is a brief overview of a scientific, clinical or review manuscript as well as a standâalone summary of a conference abstract. Scientists, clinicianâscientists and clinicians rely on the summary information provided in the abstracts of systematic reviews to assist in subsequent clinical decisionâmaking. The Preferred Reporting Items for Systematic Reviews and MetaâAnalyses (PRISMA) for Abstracts checklist was developed to improve the quality, accuracy and completeness of abstracts associated with systematic reviews and metaâanalyses. The PRISMA for Abstracts checklist provides a framework for authors to follow, which helps them provide in the abstract the key information from the systematic review that is required by stakeholders. The PRISMA for Abstracts checklist contains 12 items (title, objectives, eligibility criteria, information sources, risk of bias, included studies, synthesis of results, description of the effect, strength and limitations, interpretation, funding and systematic review registration) under six sections (title, background, methods, results, discussion, other). The current article highlights the relevance and importance of the items in the PRISMA for Abstracts checklist to the specialty of Endodontology, while offering explanations and specific examples to assist authors when writing abstracts for systematic reviews when reported in manuscripts or submitted to conferences. Strict adherence to the PRISMA for Abstracts checklist by authors, reviewers and journal editors will result in the consistent publication of highâquality abstracts within Endodontology
Acute diverticulitis in immunocompromised patients: evidence from an international multicenter observational registry (Web-based International Register of Emergency Surgery and Trauma, Wires-T)
Background: Immunocompromised patients with acute diverticulitis are at increased risk of morbidity and mortality. The aim of this study was to compare clinical presentations, types of treatment, and outcomes between immunocompromised and immunocompetent patients with acute diverticulitis. Methods: We compared the data of patients with acute diverticulitis extracted from the Web-based International Registry of Emergency Surgery and Trauma (WIRES-T) from January 2018 to December 2021. First, two groups were identified: medical therapy (A) and surgical therapy (B). Each group was divided into three subgroups: nonimmunocompromised (grade 0), mildly to moderately (grade 1), and severely immunocompromised (grade 2). Results: Data from 482 patients were analyzedâ229 patients (47.5%) [M:F = 1:1; median age: 60 (24â95) years] in group A and 253 patients (52.5%) [M:F = 1:1; median age: 71 (26â94) years] in group B. There was a significant difference between the two groups in grade distribution: 69.9% versus 38.3% for grade 0, 26.6% versus 51% for grade 1, and 3.5% versus 10.7% for grade 2 (p < 0.00001). In group A, severe sepsis (p = 0.027) was more common in higher grades of immunodeficiency. Patients with grade 2 needed longer hospitalization (p = 0.005). In group B, a similar condition was found in terms of severe sepsis (p = 0.002), quick Sequential Organ Failure Assessment score > 2 (p = 0.0002), and Mannheim Peritonitis Index (p = 0.010). A Hartmannâs procedure is mainly performed in grades 1â2 (p < 0.0001). Major complications increased significantly after a Hartmannâs procedure (p = 0.047). Mortality was higher in the immunocompromised patients (p = 0.002). Conclusions: Immunocompromised patients with acute diverticulitis present with a more severe clinical picture. When surgery is required, immunocompromised patients mainly undergo a Hartmannâs procedure. Postoperative morbidity and mortality are, however, higher in immunocompromised patients, who also require a longer hospital stay
Polymorphisms in transcription factor binding sites and enhancer regions and pancreatic ductal adenocarcinoma risk
Genome-wide association studies (GWAS) are a powerful tool for detecting variants associated with complex traits and can help risk stratification and prevention strategies against pancreatic ductal adenocarcinoma (PDAC). However, the strict significance threshold commonly used makes it likely that many true risk loci are missed. Functional annotation of GWAS polymorphisms is a proven strategy to identify additional risk loci. We aimed to investigate single-nucleotide polymorphisms (SNP) in regulatory regions [transcription factor binding sites (TFBSs) and enhancers] that could change the expression profile of multiple genes they act upon and thereby modify PDAC risk. We analyzed a total of 12,636 PDAC cases and 43,443 controls from PanScan/PanC4 and the East Asian GWAS (discovery populations), and the PANDoRA consortium (replication population). We identified four associations that reached study-wide statistical significance in the overall meta-analysis: rs2472632(A) (enhancer variant, OR 1.10, 95%CI 1.06,1.13, p = 5.5 Ă 10â8), rs17358295(G) (enhancer variant, OR 1.16, 95%CI 1.10,1.22, p = 6.1 Ă 10â7), rs2232079(T) (TFBS variant, OR 0.88, 95%CI 0.83,0.93, p = 6.4 Ă 10â6) and rs10025845(A) (TFBS variant, OR 1.88, 95%CI 1.50,1.12, p = 1.32 Ă 10â5). The SNP with the most significant association, rs2472632, is located in an enhancer predicted to target the coiled-coil domain containing 34 oncogene. Our results provide new insights into genetic risk factors for PDAC by a focused analysis of polymorphisms in regulatory regions and demonstrating the usefulness of functional prioritization to identify loci associated with PDAC risk.</p
Polymorphisms in transcription factor binding sites and enhancer regions and pancreatic ductal adenocarcinoma risk
Genome-wide association studies (GWAS) are a powerful tool for detecting variants associated with complex traits and can help risk stratification and prevention strategies against pancreatic ductal adenocarcinoma (PDAC). However, the strict significance threshold commonly used makes it likely that many true risk loci are missed. Functional annotation of GWAS polymorphisms is a proven strategy to identify additional risk loci. We aimed to investigate single-nucleotide polymorphisms (SNP) in regulatory regions [transcription factor binding sites (TFBSs) and enhancers] that could change the expression profile of multiple genes they act upon and thereby modify PDAC risk. We analyzed a total of 12,636 PDAC cases and 43,443 controls from PanScan/PanC4 and the East Asian GWAS (discovery populations), and the PANDoRA consortium (replication population). We identified four associations that reached study-wide statistical significance in the overall meta-analysis: rs2472632(A) (enhancer variant, OR 1.10, 95%CI 1.06,1.13, p = 5.5 Ă 10â8), rs17358295(G) (enhancer variant, OR 1.16, 95%CI 1.10,1.22, p = 6.1 Ă 10â7), rs2232079(T) (TFBS variant, OR 0.88, 95%CI 0.83,0.93, p = 6.4 Ă 10â6) and rs10025845(A) (TFBS variant, OR 1.88, 95%CI 1.50,1.12, p = 1.32 Ă 10â5). The SNP with the most significant association, rs2472632, is located in an enhancer predicted to target the coiled-coil domain containing 34 oncogene. Our results provide new insights into genetic risk factors for PDAC by a focused analysis of polymorphisms in regulatory regions and demonstrating the usefulness of functional prioritization to identify loci associated with PDAC risk.</p
A performance comparison of static VAr compensator based on Goertzel and FFT algorithm and experimental validation
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