107 research outputs found
An Integrated Subharmonic Coupled-Oscillator Scheme for a 60-GHz Phased-Array Transmitter
This paper describes the design of an integrated coupled-oscillator array in SiGe for millimeter-wave applications. The design focuses on a scalable radio architecture where multiple dies are tiled to form larger arrays. A 2 × 2 oscillator array for a 60-GHz transmitter is fabricated with integrated power amplifiers and on-chip antennas. To lock between multiple dies, an injection-locking scheme appropriate for wire-bond interconnects is described. The 2 × 2 array demonstrates a 200–MHz locking range and 1 × 4 array formed by two adjacent chips has a 60-MHz locking range. The phase noise of the coupled oscillators is below 100 dBc/Hz at a 1-MHz offset when locked to an external reference. To the best of the authors’ knowledge, this is the highest frequency demonstration of coupled oscillators fabricated in a conventional silicon integrated-circuit process
Key Information Retrieval in Hyperspectral Imagery through Spatial-Spectral Data Fusion
Hyperspectral (HS) imaging is measuring the radiance of materials within each pixel area at a large number of contiguous spectral wavelength bands. The key spatial information such as small targets and border lines are hard to be precisely detected from HS data due to the technological constraints. Therefore, the need for image processing techniques is an important field of research in HS remote sensing. A novel semisupervised spatial-spectral data fusion method for resolution enhancement of HS images through maximizing the spatial correlation of the endmembers (signature of pure or purest materials in the scene) using a superresolution mapping (SRM) technique is proposed in this paper. The method adopts a linear mixture model and a fully constrained least squares spectral unmixing algorithm to obtain the endmember abundances (fractional images) of HS images. Then, the extracted endmember distribution maps are fused with the spatial information using a spatial-spectral correlation maximizing model and a learning-based SRM technique to exploit the subpixel level data. The obtained results validate the reliability of the technique for key information retrieval. The proposed method is very efficient and is low in terms of computational cost which makes it favorable for real-time applications
Quadrature Subharmonic Coupled Oscillators for a 60GHz SiGe Scalable Phased Array
This paper describes an integrated coupled oscillator array in SiGe for millimeter wave applications. The design focuses on scalable radio architectures where multiple dies are tiled to form larger arrays. A 2 x 2 oscillator array for a 60GHz transmitter is designed with integrated power amplifiers and antennas. The 2 x 2 array demonstrates a 200MHz locking range and 1 x 4 array formed by two adjacent chips has a 60MHz locking range. The phase noise of the array is below -110dBc/Hz at a 1MHz offset
An Integrated Subharmonic Coupled-Oscillator Scheme for a 60-GHz Phased-Array Transmitter
Recommended from our members
Using Social Media to Recruit Seldom-Heard Groups: Reaching Women and Girls with Experience of Violence in Iran
Social media recruitment and online surveys are valuable tools in social science research, but their effectiveness in reaching seldom-heard victims of gender violence in low-middle income (LMI) countries is under-explored. This empirical study aims to: (1) describe violence and abuse experiences and (2) assess the benefits and limitations of using social media to document violence against women and girls (VAWGs) in a LMI country to render visible the experiences of potentially isolated victims. A total of 453 Iranian women (aged 14–59, mean = 28.8, SD = 8.04) responded to an Instagram invitation for a study on women’s health and violence exposure from February 2020 to January 2022. The questionnaire covered general gendered abuse, domestic violence (DV), and forced unemployment. The analysis was performed using Stata 17. Nearly all participants reported abuse, including sexual (85.0%), psychological (83.4%), and technology-facilitated (57.4%) abuse, with 77.4% experiencing multiple forms. The street (62%) and home (52.8%) were common abuse locations. The perpetrators included known individuals (75.9%) and strangers (80.8%), with 56.7% reporting abuse by both. DV was reported by 72.6%, mainly involving psychological (73.1%), physical (53.4%), and/or sexual (17.2%) violence, with fathers (47.8%), husbands (42.7%), and brothers (40.2%) as frequent perpetrators. A quarter reported forced unemployment. Those experiencing DV and/or forced unemployment showed higher depression levels, suicidal ideation, and lower marital satisfaction. The study suggests using social media recruitment for VAWG research but cautions against overgeneralising from these data
Gender-based difference in early mortality among patients with ST-segment elevation myocardial infarction: insights from Kermanshah STEMI Registry.
Introduction: This study aimed to evaluate the in-hospital mortality of patients with ST-segment elevation myocardial infarction (STEMI), according to gender and other likely risk factors. Methods: This study reports on data relating to 1,484 consecutive patients with STEMI registered from June 2016 to May 2018 in the Western Iran STEMI Registry. Data were collected using a standardized case report developed by the European Observational Registry Program (EORP). The relationship between in-hospital mortality and potential predicting variables was assessed multivariable logistic regression. Differences between groups in mortality rates were compared using chi-square tests and independent t-tests. Results: Out of the 1484 patients, 311(21%) were female. Women were different from men in terms of age (65.8 vs. 59), prevalence of hypertension (HTN) (63.7% vs. 35.4%), diabetes mellitus (DM) (37.7% vs. 16.2%), hypercholesterolemia (36.7% vs. 18.5%) and the history of previous congestive heart failure (CHF) (6.6% vs. 3.0%). Smoking was more prevalent among men (55.9% vs. 13.2%). Although the in-hospital mortality rate was higher in women (11.6% vs. 5.5%), after adjusting for other risk factors, female sex was not an independent predictor for in-hospital mortality. Multivariable analysis identified that age and higher Killip class (≥II) were significantly associated with in-hospital mortality rate. Conclusion: In-hospital mortality after STEMI in women was higher than men. However, the role of sex as an independent predictor of mortality disappeared in regression analysis. The gender based difference in in-hospital mortality after STEMI may be related to the poorer cardiovascular disease (CVD) risk factor profile of the women
Effects of hair follicle stem cells on partial-thickness burn wound healing and tensile strength
Background: The recent improvements in wound healing have led to new strategies in regenerative medicine. Burn wound healing is an important issue in skin regeneration and has multiple indications for stem cell therapy. HFSCs are a highly promising source of stem cells for healing use, as these cells are accessible, active and pluripotent adult stem cells. Methods: HFSCs of the rat whisker were isolated, cultured, and labeled with DiI. Flow cytometry method was used to detect special markers of HFSCs. Deep partial-thickness burn wound was created, and labeled HFSCs were injected around the wound bed. Wound closure was recorded via digital photographs. The inflicted rats were sacrificed at 3, 7, or 14 days post burn and used for subsequent histological and tensiometry analysis. Results: Our results indicated that HFSCs were positive for Nestin and CD34 markers, but negative for Kr15. Morphological and histological photographs revealed that wound closure rate was accelerated in stem cell-treated group compared with other groups. In addition, faster re-epithelialization and collagen deposition were observed. The immunohistochemical analysis suggested that CD31 expression and vascular density enhanced in the stem cell-treated group. Further, tissue tensile strength increased in HFSCs-treated rats in comparison to the control group. Conclusion: The present study demonstrates that HFSCs could accelerate burn wound healing as well as tensile strength in rats. © 2020, Pasteur Institute of Iran. All rights reserved
Time-Fractional KdV Equation: Formulation and Solution using Variational Methods
In this work, the semi-inverse method has been used to derive the Lagrangian
of the Korteweg-de Vries (KdV) equation. Then, the time operator of the
Lagrangian of the KdV equation has been transformed into fractional domain in
terms of the left-Riemann-Liouville fractional differential operator. The
variational of the functional of this Lagrangian leads neatly to Euler-Lagrange
equation. Via Agrawal's method, one can easily derive the time-fractional KdV
equation from this Euler-Lagrange equation. Remarkably, the time-fractional
term in the resulting KdV equation is obtained in Riesz fractional derivative
in a direct manner. As a second step, the derived time-fractional KdV equation
is solved using He's variational-iteration method. The calculations are carried
out using initial condition depends on the nonlinear and dispersion
coefficients of the KdV equation. We remark that more pronounced effects and
deeper insight into the formation and properties of the resulting solitary wave
by additionally considering the fractional order derivative beside the
nonlinearity and dispersion terms.Comment: The paper has been rewritten, 12 pages, 3 figure
The emerging role of exosomal miRNAs as a diagnostic and therapeutic biomarker in Mycobacterium tuberculosis infection
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), has been the world�s driving fatal bacterial contagious disease globally. It continues a public health emergency, and around one-third of the global community has been affected by latent TB infection (LTBI). This is mostly due to the difficulty in diagnosing and treating patients with TB and LTBI. Exosomes are nanovesicles (40�100 nm) released from different cell types, containing proteins, lipids, mRNA, and miRNA, and they allow the transfer of one�s cargo to other cells. The functional and diagnostic potential of exosomal miRNAs has been demonstrated in bacterial infections, including TB. Besides, it has been recognized that cells infected by intracellular pathogens such as Mtb can be secreting an exosome, which is implicated in the infection�s fate. Exosomes, therefore, open a unique viewpoint on the investigative process of TB pathogenicity. This study explores the possible function of exosomal miRNAs as a diagnostic biomarker. Moreover, we include the latest data on the pathogenic and therapeutic role of exosomal miRNAs in TB. © 2021, The Author(s)
- …