| 1. |
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| 2. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 3. |
- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 4. |
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- 2019
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Journal article (peer-reviewed)
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| 5. |
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| 6. |
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| 7. |
- Tang, Hu, et al.
(author)
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Boron-Rich Molybdenum Boride with Unusual Short-Range Vacancy Ordering, Anisotropic Hardness, and Superconductivity
- 2020
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In: Chemistry of Materials. - : AMER CHEMICAL SOC. - 0897-4756 .- 1520-5002. ; 32:1, s. 459-467
-
Journal article (peer-reviewed)abstract
- Determination of the structures of materials involving more light elements such as boron-rich compounds is challenging and technically important in understanding their varied compositions and superior functionalities. Here we resolve the long-standing uncertainties in structure and composition about the highest boride (termed MoB4, Mo1-xB3, or MoB3) through the rapid formation of large sized boron-rich molybdenum boride under pressure. Using high-quality single-crystal X-ray diffraction analysis and aberration-corrected scanning transmission electron microscopy, we reveal that boron-rich molybdenum boride with a composition of Mo0.757B3 exhibits P6(3)/mmc symmetry with a partial occupancy of 0.514 in 211 Mo sites (Mol), and direct observations reveal the short-range ordering of cation vacancies in (010) crystal planes. Large anisotropic Young's moduli and Vickers hardness are seen for Mo0.757B3, which may be attributed by its two-dimensional boron distributions. Mo0.757B3 is also found to be superconducting with a transition temperature (T-c) of 2.4 K, which was confirmed by measurements of resistivity and magnetic susceptibility. Theoretical calculations suggest that the partial occupancy of Mo atoms plays a crucial role in the emergence of superconductivity.
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| 8. |
- Alcorn, J, et al.
(author)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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In: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Journal article (peer-reviewed)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 9. |
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| 10. |
- Campbell, PJ, et al.
(author)
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Pan-cancer analysis of whole genomes
- 2020
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In: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
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Journal article (peer-reviewed)abstract
- Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
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| 11. |
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| 12. |
- Gao, X, et al.
(author)
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Longitudinal patient-reported outcomes 1 year after thoracoscopic segmentectomy versus lobectomy for early-stage lung cancer: a multicentre, prospective cohort study protocol
- 2023
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In: BMJ open. - : BMJ. - 2044-6055. ; 13:1, s. e067841-
-
Journal article (peer-reviewed)abstract
- Segmentectomy and lobectomy are the main surgical procedures for early-stage lung cancer. However, few studies have analysed patient-reported outcomes after segmentectomy versus lobectomy. This study aims to compare patient-reported outcomes—such as symptoms, daily functioning and quality of life—between thoracoscopic segmentectomy and lobectomy for early-stage lung cancer during the 1 year after surgery.Methods and analysisOverall, 788 newly diagnosed patients with early-stage lung cancer (tumour size ≤2 cm), who are scheduled to undergo thoracoscopic segmentectomy or lobectomy, will be recruited in this multicentre, prospective cohort study. The patients will receive standardised care after surgery. The Perioperative Symptom Assessment for Lung Surgery—a validated lung cancer surgery-specific scale—will be used to assess the symptoms and functions at baseline, at discharge and monthly after discharge for 1 year. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and Lung Cancer module 29 will be used to assess the patients’ quality of life at the same time points. The primary outcome will be the shortness of breath scores during the first year after thoracoscopic segmentectomy and lobectomy and will be compared using mixed-effects models. The secondary outcomes will include other symptoms, indicators of daily functioning, quality of life scores and traditional clinical outcomes. These will be compared using mixed-effects models and the Student’s t-test, non-parametric test or Χ2test. Propensity score matching will be used to ensure an even distribution of known confounders between the groups.Ethics and disseminationThe Ethics Committee for Medical Research and New Medical Technology of Sichuan Cancer Hospital approved this study (approval number: SCCHEC-02-2022-002). All participants will be instructed to provide informed consent. The manuscript is based on protocol version 3.0. The study results will be presented at medical conferences and published in peer-reviewed journals.Trial registration numberChiCTR2200060753.
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| 13. |
- Gao, Zhihui, et al.
(author)
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Mitochondria chaperone GRP75 moonlighting as a cell cycle controller to derail endocytosis provides an opportunity for nanomicrosphere intracellular delivery
- 2017
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In: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 8:35, s. 58536-58552
-
Journal article (peer-reviewed)abstract
- Understanding how cancer cells regulate endocytosis during the cell cycle could lead us to capitalize this event pharmacologically. Although certain endocytosis pathways are attenuated during mitosis, the endocytosis shift and regulation during the cell cycle have not been well clarified. The conventional concept of glucose-regulated proteins (GRPs) as protein folding chaperones was updated by discoveries that translocated GRPs assume moonlighting functions that modify the immune response, regulate viral release, and control intracellular trafficking. In this study, GRP75, a mitochondria matrix chaperone, was discovered to be highly expressed in mitotic cancer cells. Using synchronized cell models and the GRP75 gene knockdown and ectopic overexpression strategy, we showed that: (1) clathrin-mediated endocytosis (CME) was inhibited whereas clathrinindependent endocytosis (CIE) was unchanged or even up-regulated in the cell cycle M-phase; (2) GRP75 inhibited CME but promoted CIE in the M-phase, which is largely due to its high expression in cancer cell mitochondria; (3) GRP75 targeting by its small molecular inhibitor MKT-077 enhanced cell cycle G1 phase-privileged CME, which provides an opportunity for intracellular delivery of nanomicrospheres sized from 40 nm to 100 nm. Together, our results revealed that GRP75 moonlights as a cell cycle controller and endocytosis regulator in cancer cells, and thus has potential as a novel interference target for nanoparticle drugs delivery into dormant cancer cells.
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| 14. |
- Jacobs, Kevin B, et al.
(author)
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Detectable clonal mosaicism and its relationship to aging and cancer.
- 2012
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In: Nature Genetics. - New York : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 44:6, s. 651-658
-
Journal article (peer-reviewed)abstract
- In an analysis of 31,717 cancer cases and 26,136 cancer-free controls from 13 genome-wide association studies, we observed large chromosomal abnormalities in a subset of clones in DNA obtained from blood or buccal samples. We observed mosaic abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of >2 Mb in size in autosomes of 517 individuals (0.89%), with abnormal cell proportions of between 7% and 95%. In cancer-free individuals, frequency increased with age, from 0.23% under 50 years to 1.91% between 75 and 79 years (P = 4.8 × 10(-8)). Mosaic abnormalities were more frequent in individuals with solid tumors (0.97% versus 0.74% in cancer-free individuals; odds ratio (OR) = 1.25; P = 0.016), with stronger association with cases who had DNA collected before diagnosis or treatment (OR = 1.45; P = 0.0005). Detectable mosaicism was also more common in individuals for whom DNA was collected at least 1 year before diagnosis with leukemia compared to cancer-free individuals (OR = 35.4; P = 3.8 × 10(-11)). These findings underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases.
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| 15. |
- Jin, Ying-Hui, et al.
(author)
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Chemoprophylaxis, diagnosis, treatments, and discharge management of COVID-19 : An evidence-based clinical practice guideline (updated version)
- 2020
-
In: Military Medical Research. - : Springer Science and Business Media LLC. - 2054-9369. ; 7:1
-
Journal article (peer-reviewed)abstract
- The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a rapidly spreading illness, coronavirus disease 2019 (COVID-19), affecting more than seventeen million people around the world. Diagnosis and treatment guidelines for clinicians caring for patients are needed. In the early stage, we have issued "A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version)"; now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline. We formed a working group of clinical experts and methodologists. The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas: chemoprophylaxis, diagnosis, treatments, and discharge management. We searched the literature for direct evidence on the management of COVID-19, and assessed its certainty generated recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Recommendations were either strong or weak, or in the form of ungraded consensus-based statement. Finally, we issued 34 statements. Among them, 6 were strong recommendations for, 14 were weak recommendations for, 3 were weak recommendations against and 11 were ungraded consensus-based statement. They covered topics of chemoprophylaxis (including agents and Traditional Chinese Medicine (TCM) agents), diagnosis (including clinical manifestations, reverse transcription-polymerase chain reaction (RT-PCR), respiratory tract specimens, IgM and IgG antibody tests, chest computed tomography, chest x-ray, and CT features of asymptomatic infections), treatments (including lopinavir-ritonavir, umifenovir, favipiravir, interferon, remdesivir, combination of antiviral drugs, hydroxychloroquine/chloroquine, interleukin-6 inhibitors, interleukin-1 inhibitors, glucocorticoid, qingfei paidu decoction, lianhua qingwen granules/capsules, convalescent plasma, lung transplantation, invasive or noninvasive ventilation, and extracorporeal membrane oxygenation (ECMO)), and discharge management (including discharge criteria and management plan in patients whose RT-PCR retesting shows SARS-CoV-2 positive after discharge). We also created two figures of these recommendations for the implementation purpose. We hope these recommendations can help support healthcare workers caring for COVID-19 patients.
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| 16. |
- Lu, Yingchang, et al.
(author)
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Identification of Novel Loci and New Risk Variant in Known Loci for Colorectal Cancer Risk in East Asians
- 2020
-
In: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 29:2, s. 477-486
-
Journal article (peer-reviewed)abstract
- Background: Risk variants identified so far for colorectal cancer explain only a small proportion of milial risk of this cancer, particularly in Asians.Methods: We performed a genome-wide association study (GWAS) of colorectal cancer in East Asians, cluding 23,572 colorectal cancer cases and 48,700 controls. To identify novel risk loci, we selected 60 omising risk variants for replication using data from 58,131 colorectal cancer cases and 67,347 controls European descent. To identify additional risk variants in known colorectal cancer loci, we performed nditional analyses in East Asians.Results: An indel variant, rs67052019 at 1p13.3, was found to be associated with colorectal cancer risk P = 3.9 x 10(-8) in Asians (OR per allele deletion = 1.13, 95% confidence interval = 1.08-1.18). This sociation was replicated in European descendants using a variant (rs2938616) in complete linkage sequilibrium with rs67052019 (P = 7.7 x 10(-3)). Of the remaining 59 variants, 12 showed an association P < 0.05 in the European-ancestry study, including rs11108175 and rs9634162 at P < 5 x 10(-8) and o variants with an association near the genome-wide significance level (rs60911071, P = 5.8 x 10(-8); 62558833, P = 7.5 x 10(-8)) in the combined analyses of Asian- and European-ancestry data. In addition, ing data from East Asians, we identified 13 new risk variants at 11 loci reported from previous GWAS.Conclusions: In this large GWAS, we identified three novel risk loci and two highly suggestive loci for lorectal cancer risk and provided evidence for potential roles of multiple genes and pathways in the iology of colorectal cancer. In addition, we showed that additional risk variants exist in many colorectal ncer risk loci identified previously.Impact: Our study provides novel data to improve the understanding of the genetic basis for colorectal ncer risk.
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| 17. |
- Sung, Yun Ju, et al.
(author)
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A multi-ancestry genome-wide study incorporating gene-smoking interactions identifies multiple new loci for pulse pressure and mean arterial pressure
- 2019
-
In: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 28:15, s. 2615-2633
-
Journal article (peer-reviewed)abstract
- Elevated blood pressure (BP), a leading cause of global morbidity and mortality, is influenced by both genetic and lifestyle factors. Cigarette smoking is one such lifestyle factor. Across five ancestries, we performed a genome-wide gene–smoking interaction study of mean arterial pressure (MAP) and pulse pressure (PP) in 129 913 individuals in stage 1 and follow-up analysis in 480 178 additional individuals in stage 2. We report here 136 loci significantly associated with MAP and/or PP. Of these, 61 were previously published through main-effect analysis of BP traits, 37 were recently reported by us for systolic BP and/or diastolic BP through gene–smoking interaction analysis and 38 were newly identified (P < 5 × 10−8, false discovery rate < 0.05). We also identified nine new signals near known loci. Of the 136 loci, 8 showed significant interaction with smoking status. They include CSMD1 previously reported for insulin resistance and BP in the spontaneously hypertensive rats. Many of the 38 new loci show biologic plausibility for a role in BP regulation. SLC26A7 encodes a chloride/bicarbonate exchanger expressed in the renal outer medullary collecting duct. AVPR1A is widely expressed, including in vascular smooth muscle cells, kidney, myocardium and brain. FHAD1 is a long non-coding RNA overexpressed in heart failure. TMEM51 was associated with contractile function in cardiomyocytes. CASP9 plays a central role in cardiomyocyte apoptosis. Identified only in African ancestry were 30 novel loci. Our findings highlight the value of multi-ancestry investigations, particularly in studies of interaction with lifestyle factors, where genomic and lifestyle differences may contribute to novel findings.
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| 18. |
- Wang, Fang, et al.
(author)
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Emerging contaminants: A One Health perspective
- 2024
-
In: Innovation. - 2666-6758. ; 5
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Research review (peer-reviewed)abstract
- Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health. Despite global efforts to mitigate legacy pollutants, the continuous introduction of new substances remains a major threat to both people and the planet. In response, global initiatives are focusing on risk assessment and regulation of emerging contaminants, as demonstrated by the ongoing efforts to establish the UN's Intergovernmental Science-Policy Panel on Chemicals, Waste, and Pollution Prevention. This review identifies the sources and impacts of emerging contaminants on planetary health, emphasizing the importance of adopting a One Health approach. Strategies for monitoring and addressing these pollutants are discussed, underscoring the need for robust and socially equitable environmental policies at both regional and international levels. Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.
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| 19. |
- Wang, Xiang-Gao, et al.
(author)
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HOW BAD OR GOOD ARE THE EXTERNAL FORWARD SHOCK AFTERGLOW MODELS OF GAMMA-RAY BURSTS?
- 2015
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In: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 219:1
-
Journal article (peer-reviewed)abstract
- The external forward shock models have been the standard paradigm to interpret the broadband afterglow data of gamma-ray bursts (GRBs). One prediction of the models is that some afterglow temporal breaks at different energy bands should be achromatic; that is, the break times should be the same in different frequencies. Multiwavelength observations in the Swift era have revealed chromatic afterglow behaviors at least in some GRBs, casting doubts on the external forward shock origin of GRB afterglows. In this paper, using a large sample of GRBs with both X-ray and optical afterglow data, we perform a systematic study to address the question: how bad or good are the external forward shock models? Our sample includes 85 GRBs up to 2014 March with well-monitored X-ray and optical light curves. Based on how well the data abide by the external forward shock models, we categorize them into five grades and three samples. The first two grades (Grade I and II) include 45 of 85 GRBs. They show evidence of, or are consistent with having, an achromatic break. The temporal and spectral behaviors in each afterglow segment are consistent with the predictions (the "closure relations") of the forward shock models. These GRBs are included in the Gold sample. The next two grades (Grade III and IV) include 37 of 85 GRBs. They are also consistent with having an achromatic break, even though one or more afterglow segments do not comply with the closure relations. These GRBs are included in the Silver sample. Finally, Grade V (3/85) shows direct evidence of chromatic behaviors, suggesting that the external shock models are inconsistent with the data. These are included in the Bad sample. We further perform statistical analyses of various observational properties (temporal index alpha, spectral index beta, break time t(b)) and model parameters (energy injection index q, electron spectral index p, jet opening angle theta(j), radiative efficiency eta(gamma), and so on) of the GRBs in the Gold sample, and derive constraints on the magnetization parameter epsilon(B) in the forward shock. Overall, we conclude that the simplest external forward shock models can account for the multiwavelength afterglow data of at least half of the GRBs. When more advanced modeling (e.g., long-lasting reverse shock, structured jets, arbitrary circumburst medium density profile) is invoked, up to >90% of the afterglows may be interpreted within the framework of the external shock models.
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| 20. |
- Wang, Zhaoming, et al.
(author)
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Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33
- 2014
-
In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
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Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.
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| 21. |
- You, Xiaohu, et al.
(author)
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Towards 6G wireless communication networks: vision, enabling technologies, and new paradigm shifts
- 2021
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In: Science China Information Sciences. - : Science Press. - 1674-733X .- 1869-1919. ; 64:1
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Research review (peer-reviewed)abstract
- The fifth generation (5G) wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability, and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation (6G) wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle (UAV) communication networks, thus achieving a space-air-ground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6 GHz, millimeter wave (mmWave), terahertz (THz), and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence (AI) and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.
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| 22. |
- Yu, Sheng-Xiang, et al.
(author)
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Phylogeny of Impatiens (Balsaminaceae) : integrating molecular and morphological evidence into a new classification
- 2016
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In: Cladistics. - : Wiley-Blackwell. - 0748-3007 .- 1096-0031. ; 32:2, s. 179-197
-
Journal article (peer-reviewed)abstract
- Impatiens L. is one of the largest angiosperm genera, containing over 1000 species, and is notorious for its taxonomic difficulty. Here, we present, to our knowledge, the most comprehensive phylogenetic analysis of the genus to date based on a total evidence approach. Forty-six morphological characters, mainly obtained from our own investigations, are combined with sequence data from three genetic regions, including nuclear ribosomal ITS and plastid atpB-rbcL and trnL-F. We include 150 Impatiens species representing all clades recovered by previous phylogenetic analyses as well as three outgroups. Maximum-parsimony and Bayesian inference methods were used to infer phylogenetic relationships. Our analyses concur with previous studies, but in most cases provide stronger support. Impatiens splits into two major clades. For the first time, we report that species with three-colpate pollen and four carpels form a monophyletic group (clade I). Within clade II, seven well-supported subclades are recognized. Within this phylogenetic framework, character evolution is reconstructed, and diagnostic morphological characters for different clades and subclades are identified and discussed. Based on both morphological and molecular evidence, a new classification outline is presented, in which Impatiens is divided into two subgenera, subgen. Clavicarpa and subgen. Impatiens; the latter is further subdivided into seven sections.
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| 23. |
- Zhang, Shuangshuang, et al.
(author)
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Discovery of carbon-based strongest and hardest amorphous material
- 2022
-
In: National Science Review. - : Oxford University Press. - 2095-5138 .- 2053-714X. ; 9:1
-
Journal article (peer-reviewed)abstract
- Carbon is one of the most fascinating elements due to its structurally diverse allotropic forms stemming from its bonding varieties (sp, sp2, and sp3). Exploring new forms of carbon has always been the eternal theme of scientific research. Herein, we report the amorphous (AM) carbon materials with high fraction of sp3 bonding recovered from compression of fullerene C60 under high pressure and high temperature previously unexplored. Analysis of photoluminescence and absorption spectra demonstrates that they are semiconducting with a bandgap range of 1.5–2.2 eV, comparable to that of widely used amorphous silicon. Comprehensive mechanical tests demonstrate that the synthesized AM-III carbon is the hardest and strongest amorphous material known so far, which can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance.
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| 24. |
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| 25. |
- Bourdoux, Andre, et al.
(author)
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D1.2 MaMi Channel Characteristics: Measurement Results
- 2015
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Reports (other academic/artistic)abstract
- This deliverable presents channel measurement results for the scenariosOpen exhibition and Crowded auditiorium. The measurement procedureand equipment are described. Massive MIMO (MaMi) channel characteristicsand key parameters are extracted and used in an extended COST 2100channel model for MaMi. The initial validation performed shows that themodel is capable of reproducing the statistics in terms of temporal behaviorof the user separability, singular value spread, capacity and sum-rate anddirectional characteristics. The model can be used for system and link levelMaMi simulations.
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| 26. |
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| 27. |
- Campbell, Peter T, et al.
(author)
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Body Size Indicators and Risk of Gallbladder Cancer : Pooled Analysis of Individual-Level Data from 19 Prospective Cohort Studies.
- 2017
-
In: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 26:4, s. 597-606
-
Journal article (peer-reviewed)abstract
- Background: There are few established risk factors for gallbladder cancer beyond gallstones. Recent studies suggest a higher risk with high body mass index (BMI), an indicator of general heaviness, but evidence from other body size measures is lacking.Methods: Associations of adult BMI, young adult BMI, height, adult weight gain, waist circumference (WC), waist-height ratio (WHtR), hip circumference (HC), and waist-hip ratio (WHR) with gallbladder cancer risk were evaluated. Individual-level data from 1,878,801 participants in 19 prospective cohort studies (14 studies had circumference measures) were harmonized and included in this analysis. Multivariable Cox proportional hazards regression estimated hazard ratios (HR) and 95% confidence intervals (CI).Results: After enrollment, 567 gallbladder cancer cases were identified during 20.1 million person-years of observation, including 361 cases with WC measures. Higher adult BMI (per 5 kg/m2, HR: 1.24; 95% CI, 1.13-1.35), young adult BMI (per 5 kg/m2, HR: 1.12; 95% CI, 1.00-1.26), adult weight gain (per 5 kg, HR: 1.07; 95% CI, 1.02-1.12), height (per 5 cm, HR: 1.10; 95% CI, 1.03-1.17), WC (per 5 cm, HR: 1.09; 95% CI, 1.02-1.17), WHtR (per 0.1 unit, HR: 1.24; 95% CI, 1.00-1.54), and HC (per 5 cm, HR: 1.13; 95% CI, 1.04-1.22), but not WHR (per 0.1 unit, HR: 1.03; 95% CI, 0.87-1.22), were associated with higher risks of gallbladder cancer, and results did not differ meaningfully by sex or other demographic/lifestyle factors.Conclusions: These findings indicate that measures of overall and central excess body weight are associated with higher gallbladder cancer risks.Impact: Excess body weight is an important, and potentially preventable, gallbladder cancer risk factor. Cancer Epidemiol Biomarkers Prev; 26(4); 597-606. ©2017 AACR.
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| 28. |
- Catania, Francesco, et al.
(author)
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Endogenous Mechanisms for the Origins of Spliceosomal Introns
- 2009
-
In: Journal of Heredity. - : Oxford University Press (OUP). - 0022-1503 .- 1465-7333. ; 100:5, s. 591-596
-
Journal article (peer-reviewed)abstract
- Over 30 years since their discovery, the origin of spliceosomal introns remains uncertain. One nearly universally accepted hypothesis maintains that spliceosomal introns originated from self-splicing group-II introns that invaded the uninterrupted genes of the last eukaryotic common ancestor (LECA) and proliferated by “insertion” events. Although this is a possible explanation for the original presence of introns and splicing machinery, the emphasis on a high number of insertion events in the genome of the LECA neglects a considerable body of empirical evidence showing that spliceosomal introns can simply arise from coding or, more generally, nonintronic sequences within genes. After presenting a concise overview of some of the most common hypotheses and mechanisms for intron origin, we propose two further hypotheses that are broadly based on central cellular processes: 1) internal gene duplication and 2) the response to aberrant and fortuitously spliced transcripts. These two nonmutually exclusive hypotheses provide a powerful way to explain the establishment of spliceosomal introns in eukaryotes without invoking an exogenous source.
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| 29. |
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| 30. |
- Chen, Hang, et al.
(author)
-
GRP75 upregulates clathrin-independent endocytosis through actin cytoskeleton reorganization mediated by the concurrent activation of Cdc42 and RhoA
- 2016
-
In: Experimental Cell Research. - : Elsevier BV. - 0014-4827. ; 343:2, s. 223-236
-
Journal article (peer-reviewed)abstract
- Therapeutic macromolecules are internalized into the cell by either clathrin-mediated endocytosis (CME) or clathrin-independent endocytosis (CIE). Although some chaperone proteins play an essential role in CME (e.g. Hsc70 in clathrin uncoating), relatively few of these proteins are functionally involved in CIE. We previously revealed a role for the mitochondrial chaperone protein GRP75 in heparan sulfate proteoglycan (HSPG)-mediated, membrane raft-associated macromolecule endocytosis. However, the mechanism underlying this process remains unclear. In this study, using a mitochondrial signal peptide-directed protein trafficking expression strategy, we demonstrate that wild-type GRP75 expression enhanced the uptakes of HSPG and CIE marker cholera toxin B subunit but impaired the uptake of CME marker transferrin. The endocytosis regulation function of GRP75 is largely mediated by its subcellular location in mitochondria and is essentially determined by its ATPase domain. Interestingly, the mitochondrial expression of GRP75 or its ATPase domain significantly stimulates increases in both RhoA and Cdc42 activation, remarkably induces stress fibers and enhances filopodia formation, which collectively results in the promotion of CIE, but the inhibition of CME. Furthermore, silencing of Cdc42 or RhoA impaired the ability of GRP75 overexpression to increase CIE. Therefore, these results suggest that endocytosis vesicle enrichment of GRP75 by mitochondria trafficking upregulates CIE through an actin cytoskeleton reorganization mechanism mediated by the concurrent activation of Cdc42 and RhoA. This finding provides novel insight into organelle-derived chaperone signaling and the regulation of different endocytosis pathways in cells.
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| 31. |
- Chen, Zemeng, et al.
(author)
-
Open access dataset integrating EEG and fNIRS during Stroop tasks
- 2023
-
In: Scientific Data. - : Springer Nature. - 2052-4463. ; 10:1
-
Journal article (peer-reviewed)abstract
- Conflict monitoring and processing are crucial components of the human cognitive system, with significant implications for daily life and the diagnosis of cognitive disorders. The Stroop task, combined with brain function detection technology, has been widely employed as a classical paradigm for investigating conflict processing. However, there remains a lack of public datasets that integrate Electroencephalogram (EEG) and functional Near-infrared Spectroscopy (fNIRS) to simultaneously record brain activity during a Stroop task. We introduce a dual-modality Stroop task dataset incorporating 34-channel EEG (sampling frequency is 1000 Hz) and 20-channel high temporal resolution fNIRS (sampling frequency is 100 Hz) measurements covering the whole frontal cerebral cortex from 21 participants (9 females/12 males, aged 23.0 ± 2.3 years). Event-related potential analysis of EEG recordings and activation analysis of fNIRS recordings were performed to show the significant Stroop effect. We expected that the data provided would be utilized to investigate multimodal data processing algorithms during cognitive processing.
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| 32. |
- Chu, Xia, et al.
(author)
-
Multiple Microvascular Alterations in Pancreatic Islets and Neuroendocrine Tumors of a Men1 Mouse Model
- 2013
-
In: American Journal of Pathology. - : Elsevier BV. - 0002-9440 .- 1525-2191. ; 182:6, s. 2355-2367
-
Journal article (peer-reviewed)abstract
- Vascular therapeutic targeting requires thorough evaluation of the mechanisms activated in the specific context of each particular tumor type. We highlight structural, molecular, and functional microvascular aberrations contributing to development and maintenance of pancreatic neuroendocrine tumors (NETs), with special reference to multiple endocrine neoplasia 1 (MEN1) syndrome, using a Men1 mouse model. Tissue samples were analyzed by immunofluorescence to detect vessel density and pericyte distribution within the endocrine pancreas; expression of angiogenic factors was assessed by immunohistochemistry and quantitative real-time PCR in isolated islets and adenomas cultured under normoxic or hypoxic conditions. The increased vascular density of pancreatic NETs developed in Men1 mice was paralleled by an early and extensive redistribution of pericytes within endocrine tissue. These morphological alterations are supported by, and in some cases preceded by, fine-tuned variations in expression of several angiogenic regulators and are further potentiated by hypoxia. By combining two novel ex vivo and in vivo single-islet and tumor perfusion techniques, we demonstrated that both vascular reactivity and blood perfusion of tumor arterioles are significantly altered in response to glucose and L-nitro-arginine methyl ester. Our findings unravel multiple potential molecular and physiological targets differentially activated in the endocrine pancreas of Men1 mice and highlight the need for in-depth functional studies to fully understand the contribution of each component to development of pancreatic NETs in MEN1 syndrome.
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| 33. |
- Deng, Shuiguang, et al.
(author)
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Dynamical Resource Allocation in Edge for Trustable Internet-of-Things Systems : A Reinforcement Learning Method
- 2020
-
In: IEEE Transactions on Industrial Informatics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1551-3203 .- 1941-0050. ; 16:9, s. 6103-6113
-
Journal article (peer-reviewed)abstract
- Edge computing (EC) is now emerging as a key paradigm to handle the increasing Internet-of-Things (IoT) devices connected to the edge of the network. By using the services deployed on the service provisioning system which is made up of edge servers nearby, these IoT devices are enabled to fulfill complex tasks effectively. Nevertheless, it also brings challenges in trustworthiness management. The volatile environment will make it difficult to comply with the service-level agreement (SLA), which is an important index of trustworthiness declared by these IoT services. In this article, by denoting the trustworthiness gain with how well the SLA can comply, we first encode the state of the service provisioning system and the resource allocation scheme and model the adjustment of allocated resources for services as a Markov decision process (MDP). Based on these, we get a trained resource allocating policy with the help of the reinforcement learning (RL) method. The trained policy can always maximize the services' trustworthiness gain by generating appropriate resource allocation schemes dynamically according to the system states. By conducting a series of experiments on the YouTube request dataset, we show that the edge service provisioning system using our approach has 21.72% better performance at least compared to baselines.
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| 34. |
- Du, Jie, et al.
(author)
-
Effects of rainfall intensity and slope on interception and precipitation partitioning by forest litter layer
- 2019
-
In: Catena. - : Elsevier BV. - 0341-8162. ; 172, s. 711-718
-
Journal article (peer-reviewed)abstract
- Rainfall interception and other hydrologic processes affected by the forest litter layer are usually related to litter characteristics and rainfall conditions, with limited studies that consider the influence of slope. To simulate the hydrological functions of the litter layer at different slope gradients, artificial rainfall experiments were conducted at four rainfall intensities (from 30 to 120 mm hr−1) in horizontal and inclined trays (with the slope of 0° 10° 20° and 30°) with litter of Pinus tabuliformis or Quercus variabilis. The results indicated that (1) the dynamic process of litter interception had 3 phases: a rapid intercepted phase within the first 5 min, a moderate intercepted phase and a post-rainfall drainage phase; (2) the maximum interception storage (Cmax) and the minimum interception storage (Cmin) of Q. variabilis were larger than those of P. tabuliformis; (3) Cmax and Cmin were correlated with slope for both types of litter, whereas only Cmax was correlated with rainfall intensity; and (4) lateral flow amount significantly increased with both slope gradient and rainfall intensity only for Quercus variabilis, whereas drainage volume showed significant correlation with rainfall intensity. Moreover, the ratio of lateral runoff and drainage was affected by slope gradient whereas percentage of litter interception had a good relationship with rainfall intensity, rather than slope, with litter interception and drainage contributing the smallest and the largest proportions, respectively. Overall, the results demonstrate the effect of rainfall and slope factors on hydrological processes in the forest litter layer.
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| 35. |
- Dutta, D, et al.
(author)
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Nuclear transparency with the gamma n ->pi(-)p process in He-4
- 2003
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 68:2: 021001
-
Journal article (peer-reviewed)abstract
- We have measured the nuclear transparency of the fundamental process gamman-->pi(-)p in He-4. These measurements were performed at Jefferson Lab in the photon energy range of 1.6-4.5 GeV and at theta(cm)(pi)=70degrees and 90degrees. These measurements are the first of their kind in the study of nuclear transparency in photoreactions. They also provide a benchmark test of Glauber calculations based on traditional models of nuclear physics. The transparency results suggest deviations from the traditional nuclear physics picture. The momentum transfer dependence of the measured nuclear transparency is consistent with Glauber calculations that include the quantum chromodynamics phenomenon of color transparency.
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| 36. |
- Fanidi, Anouar, et al.
(author)
-
Circulating Folate, Vitamin B6, and Methionine in Relation to Lung Cancer Risk in the Lung Cancer Cohort Consortium (LC3)
- 2018
-
In: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 110:1
-
Journal article (peer-reviewed)abstract
- Background: Circulating concentrations of B vitamins and factors related to one-carbon metabolism have been found to be strongly inversely associated with lung cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The extent to which these associations are present in other study populations is unknown.Methods: Within 20 prospective cohorts from the National Cancer Institute Cohort Consortium, a nested case-control study was designed including 5364 incident lung cancer case patients and 5364 control subjects who were individually matched to case patients by age, sex, cohort, and smoking status. Centralized biochemical analyses were performed to measure circulating concentrations of vitamin B6, folate, and methionine, as well as cotinine as an indicator of recent tobacco exposure. The association between these biomarkers and lung cancer risk was evaluated using conditional logistic regression models.Results: Participants with higher circulating concentrations of vitamin B6 and folate had a modestly decreased risk of lung cancer risk overall, the odds ratios when comparing the top and bottom fourths (OR 4vs1 ) being 0.88 (95% confidence interval [CI] = 0.78 to 1.00) and 0.86 (95% CI = 0.74 to 0.99), respectively. We found stronger associations among men (vitamin B6: OR 4vs1 = 0.74, 95% CI = 0.62 to 0.89; folate: OR 4vs1 = 0.75, 95% CI = 0.61 to 0.93) and ever smokers (vitamin B6: OR 4vs1 = 0.78, 95% CI = 0.67 to 0.91; folate: OR 4vs1 = 0.87, 95% CI = 0.73 to 1.03). We further noted that the association of folate was restricted to Europe/Australia and Asia, whereas no clear association was observed for the United States. Circulating concentrations of methionine were not associated with lung cancer risk overall or in important subgroups.Conclusions: Although confounding by tobacco exposure or reverse causation cannot be ruled out, these study results are compatible with a small decrease in lung cancer risk in ever smokers who avoid low concentrations of circulating folate and vitamin B6.
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| 37. |
- Fanidi, Anouar, et al.
(author)
-
Is high vitamin B12 status a cause of lung cancer?
- 2019
-
In: International Journal of Cancer. - : John Wiley & Sons. - 0020-7136 .- 1097-0215. ; 145:6, s. 1499-1503
-
Journal article (peer-reviewed)abstract
- Vitamin B supplementation can have side effects for human health, including cancer risk. We aimed to elucidate the role of vitamin B12 in lung cancer etiology via direct measurements of pre‐diagnostic circulating vitamin B12 concentrations in a nested case–control study, complemented with a Mendelian randomization (MR) approach in an independent case–control sample. We used pre‐diagnostic biomarker data from 5183 case–control pairs nested within 20 prospective cohorts, and genetic data from 29,266 cases and 56,450 controls. Exposures included directly measured circulating vitamin B12 in pre‐diagnostic blood samples from the nested case–control study, and 8 single nucleotide polymorphisms associated with vitamin B12 concentrations in the MR study. Our main outcome of interest was increased risk for lung cancer, overall and by histological subtype, per increase in circulating vitamin B12 concentrations. We found circulating vitamin B12 to be positively associated with overall lung cancer risk in a dose response fashion (odds ratio for a doubling in B12 [ORlog2B12] = 1.15, 95% confidence interval (95%CI) = 1.06–1.25). The MR analysis based on 8 genetic variants also indicated that genetically determined higher vitamin B12 concentrations were positively associated with overall lung cancer risk (OR per 150 pmol/L standard deviation increase in B12 [ORSD] = 1.08, 95%CI = 1.00–1.16). Considering the consistency of these two independent and complementary analyses, these findings support the hypothesis that high vitamin B12 status increases the risk of lung cancer.
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| 38. |
- Felbinger, Jonathan, 1984, et al.
(author)
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Fabrication and Characterization of Thin-Barrier Al05Ga05N/AlN/GaN HEMTs
- 2011
-
In: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 32:7, s. 889-891
-
Journal article (peer-reviewed)abstract
- The growth, fabrication, and performance of AlGaN/AlN/GaN high-electron-mobility transistors (HEMTs) with a total barrier thickness of 7 nm are reported. An optimized surface passivation and an Ohmic recess etch yield HEMTs exhibiting 0.72 S/mm peak extrinsic DC transconductance at a current density of 0.47 A/mm. Devices with a gate length of 90 nm achieve 78 GHz unity-current-gain frequency and up to 166 GHz maximum frequency of oscillation. The minimum noise figure at 10 GHz is 0.52 dB with an associated gain of 9.5 dB.
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| 39. |
- Flordelis, Jose, et al.
(author)
-
Exploiting antenna correlation in measured massive MIMO channels
- 2016
-
In: 2016 IEEE 27th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2016. - 9781509032549
-
Conference paper (peer-reviewed)abstract
- We investigate antenna correlation of an M-antenna massive multiple-input multiple-output (MIMO) setup with the purpose of obtaining a low-rank representation of the instantaneous massive MIMO channel. Low-rank representation bases using short-term and long-term antenna correlation statistics are defined, and their performance is evaluated with data sets obtained from channel measurements in both indoor and outdoor environments at 2.6 GHz. Our results indicate that the short-term bases can capture a larger amount of the channel energy compared to the long-term ones, but they have a limited timespan, one coherence time or less. On the other hand, the long-term bases are stable over time-spans of a few seconds. Hence, they can be obtained relatively easily. We also investigate a rank-p vector-scalar LMMSE channel estimator that exploits antenna correlation. Our results show that the investigated estimator can achieve a performance similar to that of full-rank LMMSE at a (2p + 1)/M times lower cost. The investigated estimator may be used in conjunction with estimators that exploit correlation in the frequency and time domains or, alternatively, in situations in which these estimators cannot be used, e.g., when pilot separation is larger than the channel coherence bandwidth or time.
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| 40. |
- Flordelis, Jose, et al.
(author)
-
Initial Characterization of Massive Multi-User MIMO Channels at 2.6 GHz in Indoor and Outdoor Environments
- 2015
-
Conference paper (other academic/artistic)abstract
- The channel properties have a large influence on user separability in massive multi-user multiple-input multiple-output (massive MIMO) systems. In this paper we present spatio-temporal characteristics obtained from massive MIMO channel measurements at 2.6 GHz. The results are based on data acquired in both indoor and outdoor scenarios where a base station equipped with 64 dual-polarized antenna elements communicates simultaneously with nine single-antenna users. In the outdoor scenarios the base station is placed at two rooftops with different heights and the users are confined to a five-meter diameter circle and move rando mly at pedestrian speeds. In the indoor scenarios, the users are located close to each other in a lecture theater and the base station is placed at various locations in the room. We report on the observed distribution of the delay spreads and angular spreads. Furthermore, the multi-user performance in terms of singular value spread of the MU-MIMO channel is also reported. Finally, statistics of the coherence time and coherence bandwidth of the propagation channel in various scenarios are given. The results are important for the design and analysis of massive MU-MIMO systems, as well as in the development of realistic massive MU-MIMO channel models.
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| 41. |
- Flordelis, Jose, et al.
(author)
-
Spatial Separation of Closely-Located Users in Measured Massive MIMO Channels
- 2018
-
In: IEEE Access. - 2169-3536. ; 6, s. 40253-40266
-
Journal article (peer-reviewed)abstract
- We investigate the ability of Massive multiple-input multiple-output (MIMO) systems to spatially separate up to eighteen users located close to one another in line-of-sight (LOS) propagation conditions, in both indoor and outdoor environments. For that, we use fully-synchronous measured channels at 2.6 GHz of single-antenna users moving within a small area and concurrently communicating with a base station (BS) equipped with a compact 128-port array. To quantify the degree of spatial user separability, we use three scalar metrics, namely, the achievable sum-rates, the condition number of the channel matrix, and the angle to interference factor. Our results show that Massive MIMO with zero-forcing (ZF) or regularized ZF (RZF) can spatially separate nine, even eighteen, concurrent users at practical SNR values even in the challenging case of dominant LOS propagation. In particular, signal-to-noise ratio losses relative to ideal (non-interfering and equally strong) channels can be reduced dramatically compared with standard multiuser MIMO systems, which typically have the same number of users as BS antennas. Our findings suggest that with RZF or ZF the ratio of BS antennas to number of served users should be at least three to four, to harvest most of the available spatial gains that the environment can offer. Although orthogonality and array gains complement each other, for the suggested ratios of antennas to users, the main contribution to improving system performance, measured in sum-rates, comes from the orthogonality gain.
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| 42. |
- Flordelis, Jose, et al.
(author)
-
Spatial Separation of Closely-Spaced Users in Measured Massive Multi-User MIMO Channels
- 2015
-
In: 2015 IEEE International Conference on Communications (ICC). ; , s. 1441-1446
-
Conference paper (peer-reviewed)abstract
- Fully-synchronous measurements of a massive multi-user multiple-input multiple-output (MU-MIMO) radio propagation channel are presented. We evaluate the ability of a massive MIMO system to spatially separate users located close to each other in line-of-sight (LOS) propagation conditions. The system consists of a base-station (BS) antenna array equipped with 64 dual-polarized antenna elements (128 ports) arranged in a cylindrical configuration, and eight single-antenna users. The users are confined to a five-meter diameter circle and move randomly at pedestrian speeds. The BS antenna array is located on top of a 20 m tall building and has LOS to the users. We examine user separability by studying singular value spread of the MU-MIMO channel matrix for several subsets of BS antenna array ports, along with sum-rate capacity and achievable sum-rates with both zero-forcing and matched-filtering linear precoders. We also analyze the performance of the user with the lowest rate. Finally, a comparison between the performance offered by the massive MIMO system and that of a conventional MU-MIMO system is provided. To the best of our knowledge, this is the first report of fully-synchronous dynamic measurements of a massive MIMO system. Our investigation shows that even users located close to each other in LOS propagation conditions can be spatially separated in a massive MIMO system.
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| 43. |
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| 44. |
- Gao, Ruo Bin, et al.
(author)
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A Wideband Co-Linearly Polarized Composite Antenna with High Isolation
- 2023
-
In: IEEE Antennas and Wireless Propagation Letters. - 1536-1225. ; , s. 1-5
-
Journal article (peer-reviewed)abstract
- In this paper, a high-isolation two-port co-linearly polarized (co-LP) composite antenna is proposed. Dipole and W8JK array modes with co-LP omnidirectional patterns can be simultaneously supported by a plate with two etched back-to-back tapered slots. A microstrip differential and a T-divider coupling feeding networks are developed to selectively excite the dipole and W8JK modes, which results in a high isolation and low correlation between two co-LP ports without using any decoupling structures. Reflecting ground is applied to realize the directional radiation. Measurement results show that the overlapped operating band of the antenna can cover 3.4 - 4.1 GHz with low measured envelope correlation coefficients (< 2.5 × 10-3) and high isolation (> 20 dB). Dual-polarized four-port element with good performances can be easily obtained based on the proposed co-LP antenna. The simulated results of the four-port prototype indicate that the proposed antenna is a promising candidate for the future compact massive MIMO array antenna.
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| 45. |
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| 46. |
- Gao, Xiang, et al.
(author)
-
Adenosine A(1)-receptor deficiency diminishes afferent arteriolar and blood pressure responses during nitric oxide inhibition and angiotensin II treatment
- 2011
-
In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 301:6, s. R1669-R1681
-
Journal article (peer-reviewed)abstract
- Adenosine mediates tubuloglomerular feedback responses via activation of A(1)-receptors on the renal afferent arteriole. Increased preglomerular reactivity, due to reduced nitric oxide (NO) production or increased levels of ANG II and reactive oxygen species (ROS), has been linked to hypertension. Using A(1)-receptor knockout (A(1)(-/-)) and wild-type (A(1)(+/+)) mice we investigated the hypothesis that A(1)-receptors modulate arteriolar and blood pressure responses during NO synthase (NOS) inhibition or ANG II treatment. Blood pressure and renal afferent arteriolar responses were measured in nontreated mice and in mice with prolonged N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or ANG II treatment. The hypertensive responses to L-NAME and ANG II were clearly attenuated in A(1)(-/-) mice. Arteriolar contractions to L-NAME (10(-4) mol/l; 15 min) and cumulative ANG II application (10(-12) to 10(-6) mol/l) were lower in A(1)(-/-) mice. Simultaneous treatment with tempol (10(-4) mol/l; 15 min) attenuated arteriolar responses in A(1)(+/+) but not in A(1)(-/-) mice, suggesting differences in ROS formation. Chronic treatment with L-NAME or ANG II did not alter arteriolar responses in A(1)(-/-) mice, but enhanced maximal contractions in A(1)(+/+) mice. In addition, chronic treatments were associated with higher plasma levels of dimethylarginines (asymmetrical and symmetrical) and oxidative stress marker malondialdehyde in A(1)(+/+) mice, and gene expression analysis showed reduced upregulation of NOS-isoforms and greater upregulation of NADPH oxidases. In conclusion, adenosine A(1)-receptors enhance preglomerular responses during NO inhibition and ANG II treatment. Interruption of A(1)-receptor signaling blunts L-NAME and ANG II-induced hypertension and oxidative stress and is linked to reduced responsiveness of afferent arterioles.
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| 47. |
- Gao, Xiang, et al.
(author)
-
Adenosine A1 receptor-dependent and independent pathways in modulating renal vascular responses to angiotensin II
- 2015
-
In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 213:1, s. 268-276
-
Journal article (peer-reviewed)abstract
- AIM: Renal afferent arterioles are the effector site for autoregulation of glomerular perfusion and filtration. There is synergistic interaction between angiotensin II (ANG II) and adenosine (Ado) in regulating arteriolar contraction, however, the mechanisms are not clear. In this context, this study investigated the contribution of A1 receptor dependent and independent signaling mechanisms.METHODS: Isolated perfused afferent arterioles from transgenic mice (A1+/+ and A1-/-) were used for vascular reactivity studies. Cultured vascular smooth muscle cells (VSMC) were used for phosphorylation studies of signaling proteins that induce arteriolar contraction.RESULTS: Maximal arteriolar contraction to ANG II was attenuated in A1-/- (22%) compared with A1+/+ (40%). Simultaneous incubation with low dose Ado (10-8 mol/L) enhanced ANG II-induced contraction in A1+/+ (58%), but also in A1-/- (42%). An Ado transporter inhibitor (NBTI) abolished this synergistic effect in A1-/-, but not in wild-type mice. Incubation with Ado+ANG II increased p38 phosphorylation in aortic VSMC from both genotypes, but treatment with NBTI only blocked phosphorylation in A1-/-. Combination of ANG II+Ado also increased MLC phosphorylation in A1+/+ but not significantly in A1-/-, and NBTI had no effects. In agreement, Ado+ANG II-induced phosphorylation of p38 and MLC in rat preglomerular VSMC was not affected by NBTI. However, during pharmacological inhibition of the A1 receptor simultaneous treatment with NBTI reduced phosphorylation of both p38 and MLC to control levels.CONCLUSION: Interaction between ANG II and Ado in VSMC normally involves A1 receptor signaling, but this can be compensated by receptor independent actions that phosphorylate p38 MAPK and MLC.
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| 48. |
- Gao, Xiang, et al.
(author)
-
Anchoring the ethylene-forming enzyme to photosystem-related proteins to improve ethylene production in engineered Synechocystis PCC 6803
- 2022
-
In: Bioresource Technology Reports. - : Elsevier. - 2589-014X. ; 19
-
Journal article (peer-reviewed)abstract
- Ethylene production in engineered cyanobacteria offers a sustainable alternative to the traditional production from fossil resources. Protein fusions and anchoring strategies are promising routes to augment the stability of recombinant proteins. Here we attempted to anchor the ethylene-forming enzyme (Efe) to several photosystemrelated proteins (including D1, PetF, and PsaE) in order to improve the ethylene producing capability in engineered cells of Synechocystis PCC 6803. Generated strains harboring fused Efe with D1 or PetF showed respectively 1.6- and 1.5-fold increase in ethylene production compared to a control strain harboring only Efe. Additionally, strains co-expressing a non-fused Efe with PsaE or PetF showed respectively 3.5- and 3.1-fold increase in ethylene production compared to the control strain. This work demonstrates the feasibility to incorporate (anchor or co-express) target enzyme(s) with specific photosystem components for facilitating highly efficient production of bulk chemicals in engineered cyanobacteria.
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| 49. |
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| 50. |
- Gao, Xiang, et al.
(author)
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Biotechnological Production of the Sunscreen Pigment Scytonemin in Cyanobacteria : Progress and Strategy
- 2021
-
In: Marine Drugs. - : MDPI. - 1660-3397. ; 19:3
-
Research review (peer-reviewed)abstract
- Scytonemin is a promising UV-screen and antioxidant small molecule with commercial value in cosmetics and medicine. It is solely biosynthesized in some cyanobacteria. Recently, its biosynthesis mechanism has been elucidated in the model cyanobacterium Nostoc punctiforme PCC 73102. The direct precursors for scytonemin biosynthesis are tryptophan and p-hydroxyphenylpyruvate, which are generated through the shikimate and aromatic amino acid biosynthesis pathway. More upstream substrates are the central carbon metabolism intermediates phosphoenolpyruvate and erythrose-4-phosphate. Thus, it is a long route to synthesize scytonemin from the fixed atmospheric CO2 in cyanobacteria. Metabolic engineering has risen as an important biotechnological means for achieving sustainable high-efficiency and high-yield target metabolites. In this review, we summarized the biochemical properties of this molecule, its biosynthetic gene clusters and transcriptional regulations, the associated carbon flux-driving progresses, and the host selection and biosynthetic strategies, with the aim to expand our understanding on engineering suitable cyanobacteria for cost-effective production of scytonemin in future practices.
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