Coexistence of directional and non-directional technologies in 6G wireless dense networks

Dense networks are characterized by the prevalence of wireless access points (APs) in close proximity to a population of user devices on a similar scale. By increasing AP density, the aggregate data consumption of a system can be dramatically increased. In this dissertation we consider dense deployment of directional visible light APs. Firstly, we analyze the performance of a visible light communication (VLC) link and propose algorithmic methods as well as novel receiver structures to enhance its quality. Secondly, we study handover algorithms and investigate an AP placement strategy that ties to the system outage probability. Thirdly, we use a geometric model for an indoor space and a reference optical channel model to formulate an optimization problem that proposes a dynamic field of view (FOV) receiver with a goal of optimizing receiver FOV for maximum signal to noise ratio (SNR). From the promising results we get, we then propose the dynamic FOV technique with receiver tracking capability. Its results show an average SNR increase of up to 40% when compared to a fixed FOV receiver. These results motivate the adoption of dynamic pointing and adaptive FOV at the receiver in order to realize improved performance for mobile devices in an optical wireless dense network. This opts us to study interference in VLC systems and how to mitigate it using our proposed receivers. In the context of multi-user networks, we formulate two main novel optimization problems i) a joint optimization of transmit emission pattern and transmit power while satisfying illumination requirements and ii) an optimization to allocate users, balance the network load and optimize device FOV for best performance. We then evaluate the effect of self-blockage as well as random human blockers on our proposed receivers. Finally, we propose to deploy the VLC system in a hybrid setting of other technologies to evaluate the overall system performance for future 6G networks.2022-01-17T00:00:00

Interference mitigation through user association and receiver field of view optimization in a multi-user indoor hybrid RF/VLC illuminance-constrained network

In this paper we address interference mitigation through user association and receiver field of view (FOV) optimization in a multi-user indoor optical wireless communication (OWC) scenario. We explore several dynamic FOV receiver solutions including steerable (SDFOV) and non-steerable (DFOV) to optimize performance for multiple devices experiencing orientation dynamics. We compare their performance to a baseline fixed FOV receiver (FFOV). Through modeling and simulation we find that SDFOV receivers outperform DFOV by up to 2.6x and FFOV by up to 5.6x in terms of average minimum throughput gain using our test scenario. Similarly, DFOV receivers can achieve up to 2.2x gain over FFOV receivers. For multi-user environments, we compare the performance of coordinated versus distributed system control. Results show that in the worst case, the distributed greedy system performs on average 46%, 16%, and 57% below the coordinated system for SDFOV, DFOV, and FFOV, respectively at a reduced computational complexity compared to the centralized system. We also note that the performance gap in each system diminishes with increasing transmitter Lambertian order. This analysis is done under different room coverage achieved through optimizing the transmitted power to jointly maximize the minimum received power and the standard illuminance range probability at the working plane. Next, we show the impact of self- and random-human blockage at different Lambertian orders on the minimum and average user throughput values. Lastly, we show the gains from employing the hybrid RF/VLC network compared to a VLC-only mode for two different strategies: (1) minimum-throughput-enhancing and (2) sum-throughput-enhancing.https://ieeexplore.ieee.org/abstract/document/9300130Published versio

Detection of Crimean-Congo Haemorrhagic Fever cases in a severe undifferentiated febrile illness outbreak in the Federal Republic of Sudan: A retrospective epidemiological and diagnostic cohort study

BACKGROUND: Undifferentiated febrile illness (UFI) is one of the most common reasons for people seeking healthcare in low-income countries. While illness and death due to specific infections such as malaria are often well-quantified, others are frequently uncounted and their impact underappreciated. A number of high consequence infectious diseases, including Ebola virus, are endemic or epidemic in the Federal Republic of Sudan which has experienced at least 12 UFI outbreaks, frequently associated with haemorrhage and high case fatality rates (CFR), since 2012. One of these occurred in Darfur in 2015/2016 with 594 cases and 108 deaths (CFR 18.2%). The aetiology of these outbreaks remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: We report a retrospective cohort study of the 2015/2016 Darfur outbreak, using a subset of 65 of 263 outbreak samples received by the National Public Health Laboratory which met selection criteria of sufficient sample volume and epidemiological data. Clinical features included fever (95.8%), bleeding (95.7%), headache (51.6%) and arthralgia (42.2%). No epidemiological patterns indicative of person-to-person transmission or health-worker cases were reported. Samples were tested at the Public Health England Rare and Imported Pathogens Laboratory using a bespoke panel of likely pathogens including haemorrhagic fever viruses, arboviruses and Rickettsia, Leptospira and Borrelia spp. Seven (11%) were positive for Crimean-Congo haemorrhagic fever virus (CCHFV) by real-time reverse transcription PCR. The remaining samples tested negative on all assays. CONCLUSIONS/SIGNIFICANCE: CCHFV is an important cause of fever and haemorrhage in Darfur, but not the sole major source of UFI outbreaks in Sudan. Prospective studies are needed to explore other aetiologies, including novel pathogens. The presence of CCHFV has critical infection, prevention and control as well as clinical implications for future response. Our study reinforces the need to boost surveillance, lab and investigative capacity to underpin effective response, and for local and international health security

Effect of early tranexamic acid administration on mortality, hysterectomy, and other morbidities in women with post-partum haemorrhage (WOMAN): an international, randomised, double-blind, placebo-controlled trial

Background Post-partum haemorrhage is the leading cause of maternal death worldwide. Early administration of tranexamic acid reduces deaths due to bleeding in trauma patients. We aimed to assess the effects of early administration of tranexamic acid on death, hysterectomy, and other relevant outcomes in women with post-partum haemorrhage. Methods In this randomised, double-blind, placebo-controlled trial, we recruited women aged 16 years and older with a clinical diagnosis of post-partum haemorrhage after a vaginal birth or caesarean section from 193 hospitals in 21 countries. We randomly assigned women to receive either 1 g intravenous tranexamic acid or matching placebo in addition to usual care. If bleeding continued after 30 min, or stopped and restarted within 24 h of the first dose, a second dose of 1 g of tranexamic acid or placebo could be given. Patients were assigned by selection of a numbered treatment pack from a box containing eight numbered packs that were identical apart from the pack number. Participants, care givers, and those assessing outcomes were masked to allocation. We originally planned to enrol 15 000 women with a composite primary endpoint of death from all-causes or hysterectomy within 42 days of giving birth. However, during the trial it became apparent that the decision to conduct a hysterectomy was often made at the same time as randomisation. Although tranexamic acid could influence the risk of death in these cases, it could not affect the risk of hysterectomy. We therefore increased the sample size from 15 000 to 20 000 women in order to estimate the effect of tranexamic acid on the risk of death from post-partum haemorrhage. All analyses were done on an intention-to-treat basis. This trial is registered with ISRCTN76912190 (Dec 8, 2008); ClinicalTrials.gov, number NCT00872469; and PACTR201007000192283. Findings Between March, 2010, and April, 2016, 20 060 women were enrolled and randomly assigned to receive tranexamic acid (n=10 051) or placebo (n=10 009), of whom 10 036 and 9985, respectively, were included in the analysis. Death due to bleeding was significantly reduced in women given tranexamic acid (155 [1·5%] of 10 036 patients vs 191 [1·9%] of 9985 in the placebo group, risk ratio [RR] 0·81, 95% CI 0·65–1·00; p=0·045), especially in women given treatment within 3 h of giving birth (89 [1·2%] in the tranexamic acid group vs 127 [1·7%] in the placebo group, RR 0·69, 95% CI 0·52–0·91; p=0·008). All other causes of death did not differ significantly by group. Hysterectomy was not reduced with tranexamic acid (358 [3·6%] patients in the tranexamic acid group vs 351 [3·5%] in the placebo group, RR 1·02, 95% CI 0·88–1·07; p=0·84). The composite primary endpoint of death from all causes or hysterectomy was not reduced with tranexamic acid (534 [5·3%] deaths or hysterectomies in the tranexamic acid group vs 546 [5·5%] in the placebo group, RR 0·97, 95% CI 0·87-1·09; p=0·65). Adverse events (including thromboembolic events) did not differ significantly in the tranexamic acid versus placebo group. Interpretation Tranexamic acid reduces death due to bleeding in women with post-partum haemorrhage with no adverse effects. When used as a treatment for postpartum haemorrhage, tranexamic acid should be given as soon as possible after bleeding onset. Funding London School of Hygiene & Tropical Medicine, Pfizer, UK Department of Health, Wellcome Trust, and Bill & Melinda Gates Foundation

Breast cancer management pathways during the COVID-19 pandemic: outcomes from the UK ‘Alert Level 4’ phase of the B-MaP-C study

Abstract: Background: The B-MaP-C study aimed to determine alterations to breast cancer (BC) management during the peak transmission period of the UK COVID-19 pandemic and the potential impact of these treatment decisions. Methods: This was a national cohort study of patients with early BC undergoing multidisciplinary team (MDT)-guided treatment recommendations during the pandemic, designated ‘standard’ or ‘COVID-altered’, in the preoperative, operative and post-operative setting. Findings: Of 3776 patients (from 64 UK units) in the study, 2246 (59%) had ‘COVID-altered’ management. ‘Bridging’ endocrine therapy was used (n = 951) where theatre capacity was reduced. There was increasing access to COVID-19 low-risk theatres during the study period (59%). In line with national guidance, immediate breast reconstruction was avoided (n = 299). Where adjuvant chemotherapy was omitted (n = 81), the median benefit was only 3% (IQR 2–9%) using ‘NHS Predict’. There was the rapid adoption of new evidence-based hypofractionated radiotherapy (n = 781, from 46 units). Only 14 patients (1%) tested positive for SARS-CoV-2 during their treatment journey. Conclusions: The majority of ‘COVID-altered’ management decisions were largely in line with pre-COVID evidence-based guidelines, implying that breast cancer survival outcomes are unlikely to be negatively impacted by the pandemic. However, in this study, the potential impact of delays to BC presentation or diagnosis remains unknown

3D Printing in Sustainable Buildings: Systematic Review and Applications in the United Arab Emirates

Three-dimensional printing (3DP) has been rapidly evolving to be one of the leading technology fields in the coming decades. However, as in the early years of new technologies, 3DP suffers from technical limitations and various implications. This study focuses on the applications of 3DP in the construction industry, emphasizing its environmental, financial, and social sustainability aspects. A systematic bibliographic analysis was carried out for the relevant publications which increased by 25-fold from 2014 to 2021. The 3D-printed construction projects in the United Arab Emirates (UAE) are presented to demonstrate the early 3DP technology penetration into its booming construction sector. The UAE case is of particular interest from a sustainability perspective due to the environmental footprint of the ample construction activities in the country, combined with the ambitious strategic plans to achieve sustainable development goals. This critical analysis shows that, despite the limited literature, 3DP could potentially be a sustainable alternative with up to 49% less environmental footprint and 78% more cost-effectiveness compared to conventional construction techniques. As the social sustainability aspect was the least addressed, this study discusses relevant social impact indicators and systematic assessment criteria. It is evident that 3DP is already reshaping the future of the built environment, especially in cases where 3DP is advantageous, such as customized designs, quick project delivery, and sustainability-oriented constructions

3D Printing in Sustainable Buildings: Systematic Review and Applications in the United Arab Emirates

Three-dimensional printing (3DP) has been rapidly evolving to be one of the leading technology fields in the coming decades. However, as in the early years of new technologies, 3DP suffers from technical limitations and various implications. This study focuses on the applications of 3DP in the construction industry, emphasizing its environmental, financial, and social sustainability aspects. A systematic bibliographic analysis was carried out for the relevant publications which increased by 25-fold from 2014 to 2021. The 3D-printed construction projects in the United Arab Emirates (UAE) are presented to demonstrate the early 3DP technology penetration into its booming construction sector. The UAE case is of particular interest from a sustainability perspective due to the environmental footprint of the ample construction activities in the country, combined with the ambitious strategic plans to achieve sustainable development goals. This critical analysis shows that, despite the limited literature, 3DP could potentially be a sustainable alternative with up to 49% less environmental footprint and 78% more cost-effectiveness compared to conventional construction techniques. As the social sustainability aspect was the least addressed, this study discusses relevant social impact indicators and systematic assessment criteria. It is evident that 3DP is already reshaping the future of the built environment, especially in cases where 3DP is advantageous, such as customized designs, quick project delivery, and sustainability-oriented constructions

Induction of heme oxygenase-1 contributes to survival of Mycobacterium abscessus in human macrophages-like THP-1 cells

Mycobacterium abscessus (M.abs) is a rapidly growing mycobacterial species that infects macrophages, and is an important pathogen in patients with cystic fibrosis. We studied the early stages of M.abs infection of macrophages, with emphasis on the role of heme-oxygenase-1 (HO-1) in this infection. THP-1 cells were activated using TPA into macrophage-like cells and infected with M.abs for different time points. M.abs infection robustly induced HO-1 expression in the THP-1 cells. Production of HO-1 was p38 MAPK-dependent, as p38 inhibitors suppressed HO-1 induction. Pretreatment with HO-1 inhibitors tin-protoporphyrin (SnPP) significantly inhibited M.abs growth inside macrophages. Furthermore, inhibiting HO-1 using HO-1 siRNA or the HO-1 upstream signaling molecule; Nrf2 using Nrf2 siRNA resulted in similar inhibition of M.abs. In contrast, inducing HO-1 did not increase M.abs intracellular growth above control. Products of HO-1 metabolism of heme are bilirubin, biliverdin, carbon monoxide (CO) and iron. The addition of either bilirubin or biliverdin, but not CO, completely restored the SnPP inhibitory effect and partially that with HO-1 siRNA. To understand the mechanisms, we used Syto-62 labeled M.abs to infect macrophages. Interestingly, HO-1 inhibition promoted M.abs-containing phagosome fusion with lysosomes, which should enhance M.abs killing. M.abs infection enhanced THP-1 ROS production as demonstrated by increased DHE, DCF fluorescence, and EPR signal. HO-1 inhibition further increased ROS production in infected macrophages. Our results indicate that HO-1 induction is important for M.abs growth during the early stages of infection, and that the HO-1 products bilirubin and biliverdin, perhaps through modulation of intracellular ROS levels, may be involved

Heme Oxygenase-1 Inhibition Modulates Autophagy and Augments Arsenic Trioxide Cytotoxicity in Pancreatic Cancer Cells

Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent form, accounting for more than 90% of all pancreatic malignancies. In a previous study, we found that hypoxia and chemotherapy induced expression of Heme Oxygenase-1 (HO-1) in PDAC cells and tissues. Arsenic trioxide (ATO) is the first-line chemotherapeutic drug for acute promyelocytic leukemia (APL). ATO increases the generation of reactive oxidative species (ROS) and induces apoptosis in treated cells. The clinical use of ATO for solid tumors is limited due to severe systemic toxicity. In order to reduce cytotoxic side effects and resistance and improve efficacy, it has become increasingly common to use combination therapies to treat cancers. In this study, we used ATO-sensitive and less sensitive PDAC cell lines to test the effect of combining HO-1 inhibitors (SnPP and ZnPP) with ATO on HO-1 expression, cell survival, and other parameters. Our results show that ATO significantly induced the expression of HO-1 in different PDAC cells through the p38 MAPK signaling pathway. ROS production was confirmed using the oxygen-sensitive probes DCFH and DHE, N-acetyl cysteine (NAC), an ROS scavenger, and oxidized glutathione levels (GSSG). Both ATO and HO-1 inhibitors reduced PDAC cell survival. In combined treatment, inhibiting HO-1 significantly increased ATO cytotoxicity, disrupted the GSH cycle, and induced apoptosis as measured using flow cytometry. ATO and HO-1 inhibition modulated autophagy as shown by increased expression of autophagy markers ATG5, p62, and LC3B in PDAC cells. This increase was attenuated by NAC treatment, indicating that autophagy modulation was through an ROS-dependent mechanism. In conclusion, our work explored new strategies that could lead to the development of less toxic and more effective therapies against PDAC by combining increased cellular stress and targeting autophagy