The use of variable coil pitch of helical tube on the hydro-thermal performance improvement

The use of helical tubes in heat transfer appliances is desirable due to their better heat transfer characteristics, but the higher pressure drop decreases the overall performance. The variation of pitch design of a helical tube is proposed to alleviate this situation so that the pitch number does not remain constant in the total tube length. A total of six variable pitch numbers with three different diameters are proposed and investigated on the thermal and fluid characteristics. To better understand the helical tube efficiency, PEC (performance evaluation criteria) is selected as a performance indicator in the present work and simulations are performed in a laminar regime (100 ≤ Re ≤ 1600) at a constant heat flux boundary condition using computational fluid dynamics. The numerical results show that variable radial pitch has higher effects on the overall performance than variable axial pitch, and it can intensify the helical tube performance by up to 10%. The results also indicate that increasing the tube diameter leads to heat transfer and friction factor increment while increasing the Reynolds number deteriorates the overall performance

Stochastic Simulation of Construction Methods for Multi-purpose Utility Tunnels

The traditional method of installing underground utilities (e.g., water, sewer, gas pipes, electrical cables) by burying them under roads has been used for decades. However, the repeated excavations related to this method cause problems, such as traffic congestion and business disruption, which can significantly increase financial and social costs. Multi-purpose Utility Tunnels (MUTs) are a good alternative for buried utilities. Although the initial cost of MUTs is higher than that of the traditional method, social cost savings make them more feasible, especially in dense urban areas. Different factors, such as the specifications of utilities, the location of the MUTs, and the construction method, should be investigated to determine if MUTs can be an economical and practical alternative. The construction method is one of the most important factors to assess to have a successful MUT project and reduce its impact on the surrounding area. Simulation can be used to investigate the different construction methods of MUTs. In this paper, two Stochastic Discrete Event Simulation models depicting two MUT construction methods (i.e., microtunneling and cut-and-cover) are developed to analyze the duration and cost of the MUT projects. Also, 4D simulation models of these methods are developed for constructability assessment of these projects

FuncTeller: How Well Does eFPGA Hide Functionality?

Hardware intellectual property (IP) piracy is an emerging threat to the global supply chain. Correspondingly, various countermeasures aim to protect hardware IPs, such as logic locking, camouflaging, and split manufacturing. However, these countermeasures cannot always guarantee IP security. A malicious attacker can access the layout/netlist of the hardware IP protected by these countermeasures and further retrieve the design. To eliminate/bypass these vulnerabilities, a recent approach redacts the design's IP to an embedded field-programmable gate array (eFPGA), disabling the attacker's access to the layout/netlist. eFPGAs can be programmed with arbitrary functionality. Without the bitstream, the attacker cannot recover the functionality of the protected IP. Consequently, state-of-the-art attacks are inapplicable to pirate the redacted hardware IP. In this paper, we challenge the assumed security of eFPGA-based redaction. We present an attack to retrieve the hardware IP with only black-box access to a programmed eFPGA. We observe the effect of modern electronic design automation (EDA) tools on practical hardware circuits and leverage the observation to guide our attack. Thus, our proposed method FuncTeller selects minterms to query, recovering the circuit function within a reasonable time. We demonstrate the effectiveness and efficiency of FuncTeller on multiple circuits, including academic benchmark circuits, Stanford MIPS processor, IBEX processor, Common Evaluation Platform GPS, and Cybersecurity Awareness Worldwide competition circuits. Our results show that FuncTeller achieves an average accuracy greater than 85% over these tested circuits retrieving the design's functionality.Comment: To be published in the proceedings of the 32st USENIX Security Symposium, 202

Comparison of different cephalometric variables in patients with and without history of snoring

Background: Obstructive sleep apnea syndrome has a high prevalence among adults. Cephalometric variables can be a valuable method for evaluating patients with this syndrome. The objective of this study is to evaluate and compare the craniofacial variables in subjects with and without snoring by cephalometric analysis.Methods: 40 patients were included in the study who were divided into two groups; group 1 of 20 snoring patients and group 2 control group of 20 non-snoring patients and were evaluated and compared for various cephalometric variables.Results: The distance from the hyoid bone to the mandibular plane (MP-H) was the only variable that showed a statistically significant correlation between two groups.Conclusions: Cephalometric variables are useful tools for evaluating the patients with snoring who are predisposed to obstructive sleep apnoea. The distance from the hyoid bone to the mandibular plane showed a statistically significant correlation between two groups

A TRAP for SAT: On the Imperviousness of a Transistor-Level Programmable Fabric to Satisfiability-Based Attacks

Locking-based intellectual property (IP) protection for integrated circuits (ICs) being manufactured at untrusted facilities has been largely defeated by the satisfiability (SAT) attack, which can retrieve the secret key needed for instantiating proprietary functionality on locked circuits. As a result, redaction-based methods have gained popularity as a more secure way of protecting hardware IP. Among these methods, transistor-level programming (TRAP) prohibits the outright use of SAT attacks due to the mismatch between the logic-level at which SAT attack operates and the switch-level at which the TRAP fabric is programmed. Herein, we discuss the challenges involved in launching SAT attacks on TRAP and we propose solutions which enable expression of TRAP in propositional logic modeling in a way that accurately reflects switch-level circuit capabilities. Results obtained using a transistor-level SAT attack tool-set that we developed and are releasing corroborate that SAT attacks can be launched against TRAP. However, the increased complexity of switch-level circuit modeling prevents the attack from realistically compromising all but the most trivial IP-protected designs

Circumventing the stability problems of graphene nanoribbon zigzag edges

Carbon nanostructures with zigzag edges exhibit unique properties—such as localized electronic states and spins—with exciting potential applications. Such nanostructures however are generally synthesized under vacuum because their zigzag edges are unstable under ambient conditions: a barrier that must be surmounted to achieve their scalable integration into devices for practical purposes. Here we show two chemical protection/deprotection strategies, demonstrated on labile, air-sensitive chiral graphene nanoribbons. Upon hydrogenation, the chiral graphene nanoribbons survive exposure to air, after which they are easily converted back to their original structure by annealing. We also approach the problem from another angle by synthesizing a form of the chiral graphene nanoribbons that is functionalized with ketone side groups. This oxidized form is chemically stable and can be converted to the pristine hydrocarbon form by hydrogenation and annealing. In both cases, the deprotected chiral graphene nanoribbons regain electronic properties similar to those of the pristine nanoribbons. We believe both approaches may be extended to other graphene nanoribbons and carbon-based nanostructures.Research was supported by MCIN/AEI/10.13039/501100011033 (grant nos PID2019-107338RB-C62 (D.P.), PID2019-107338RB-C63 (M.C. and D.G.d.O.) and FJC2019-041202-I (F.S.)); the European Union’s Horizon 2020 programme (grant nos 863098 (D.P.) and 635919 (D.G.d.O.), and Marie Skłodowska-Curie Actions Individual Fellowship no. 101022150 (T.W.)); the Gobierno Vasco (grant no. PIBA_2020_1_0036 (D.G.d.O.)); the Xunta de Galicia (Centro Singular de Investigación de Galicia, 2019–2022, grant no. ED431G2019/03 (D.P.)); the European Regional Development Fund; the Praemium Academie of the Academy of Science of the Czech Republic (GACR project no. 20-13692X (P.J.)); the Czech Nanolab Research Infrastructure supported by MEYS CR (project no. LM2018110 (P.J.)); and the Operational Programme for Research, Development and Education of the European Regional Development Fund (project no. CZ.02.1.01/0.0/0.0/16_019/0000754 (P.J.)).Peer reviewe

Full-thickness resection device (FTRD) for treatment of upper gastrointestinal tract lesions: the first international experience.

Background and study aims The Full-Thickness Resection Device (FTRD) provides a novel treatment option for lesions not amenable to conventional endoscopic resection techniques. There are limited data on the efficacy and safety of FTRD for resection of upper gastrointestinal tract (GIT) lesions. Patients and methods This was an international multicenter retrospective study, including patients who had an endoscopic resection of an upper GIT lesion using the FTRD between January 2017 and February 2019. Results Fifty-six patients from 13 centers were included. The most common lesions were mesenchymal neoplasms (n = 23, 41 %), adenomas (n = 7, 13 %), and hamartomas (n = 6, 11 %). Eighty-four percent of lesions were located in the stomach, and 14 % in the duodenum. The average size of lesions was 14 mm (range 3 to 33 mm). Deployment of the FTRD was technically successful in 93 % of patients (n = 52) leading to complete and partial resection in 43 (77 %) and 9 (16 %) patients, respectively. Overall, the FTRD led to negative histological margins (R0 resection) in 38 (68 %) of patients. A total of 12 (21 %) mild or moderate adverse events (AEs) were reported. Follow-up endoscopy was performed in 31 patients (55 %), on average 88 days after the procedure (IQR 68-138 days). Of these, 30 patients (97 %) did not have any residual or recurrent lesion on endoscopic examination and biopsy, with residual adenoma in one patient (3 %). Conclusions Our results suggest a high technical success rate and an acceptable histologically complete resection rate, with a low risk of AEs and early recurrence for FTRD resection of upper GIT lesions

National Estimates for the Percentage of All Readmissions with Demographic Features, Morbidity, Overall and Gender-Specific Mortality of Transcutaneous Versus Open Surgical Tricuspid Valve Replacement/Repair

BACKGROUND: The aim of the study was to determine national estimates for the percentage of all readmissions with demographic features, length of stay (LOS), cost analysis, comorbidities, complications, overall and gender-specific mortality and complications of transcutaneous tricuspid valve replacement/repair (TTVR) vs. open surgical tricuspid valve replacement/repair (open TVR). METHODS: Data were extrapolated from the Nationwide Readmissions Database (NRD) 2015-19. Of the 75,266,750 (unweighted) cases recorded in the 2015 - 2019 dataset, 429 had one or more of the percutaneous approach codes as per the ICD-10 dataset, and 10,077 had one or more of the open approach codes. RESULTS: Overall, the number of cases performed each year through open TVR was higher than TTVR, but there was an increased trend towards the TTVR every passing year. TTVR was performed more in females and advanced age groups than open TVR. The LOS and cost were lower in the TTVR group than in open TVR. Patients undergoing TTVR had more underlying comorbidities like congestive heart failure, hypertension, and uncomplicated diabetes mellitus. Overall mortality was 3.49% in TTVR vs. 6.09% in open TVR. The gender-specific analysis demonstrated higher female mortality in the open TVR compared to TTVR (5.45% vs. 3.03%). Male mortality was statistically insignificant between the two groups (6.8% vs. 4.3%, P-value = 0.15). Patients with TTVR had lower rates of complications than open TVR, except for arrhythmias, which were higher in TTVR. Patients undergoing open TVR required more intracardiac support, such as intra-aortic balloon pump (IABP) and Impella, than TTVR. CONCLUSION: TTVR is an emerging alternative to open TVR in patients with tricuspid valve diseases, especially tricuspid regurgitation. Despite having more underlying comorbidities, the TTVR group had lower in-hospital mortality, hospital cost, LOS, and fewer complications than open TVR

The unfinished agenda of communicable diseases among children and adolescents before the COVID-19 pandemic, 1990-2019: a systematic analysis of the Global Burden of Disease Study 2019

BACKGROUND: Communicable disease control has long been a focus of global health policy. There have been substantial reductions in the burden and mortality of communicable diseases among children younger than 5 years, but we know less about this burden in older children and adolescents, and it is unclear whether current programmes and policies remain aligned with targets for intervention. This knowledge is especially important for policy and programmes in the context of the COVID-19 pandemic. We aimed to use the Global Burden of Disease (GBD) Study 2019 to systematically characterise the burden of communicable diseases across childhood and adolescence. METHODS: In this systematic analysis of the GBD study from 1990 to 2019, all communicable diseases and their manifestations as modelled within GBD 2019 were included, categorised as 16 subgroups of common diseases or presentations. Data were reported for absolute count, prevalence, and incidence across measures of cause-specific mortality (deaths and years of life lost), disability (years lived with disability [YLDs]), and disease burden (disability-adjusted life-years [DALYs]) for children and adolescents aged 0-24 years. Data were reported across the Socio-demographic Index (SDI) and across time (1990-2019), and for 204 countries and territories. For HIV, we reported the mortality-to-incidence ratio (MIR) as a measure of health system performance. FINDINGS: In 2019, there were 3·0 million deaths and 30·0 million years of healthy life lost to disability (as measured by YLDs), corresponding to 288·4 million DALYs from communicable diseases among children and adolescents globally (57·3% of total communicable disease burden across all ages). Over time, there has been a shift in communicable disease burden from young children to older children and adolescents (largely driven by the considerable reductions in children younger than 5 years and slower progress elsewhere), although children younger than 5 years still accounted for most of the communicable disease burden in 2019. Disease burden and mortality were predominantly in low-SDI settings, with high and high-middle SDI settings also having an appreciable burden of communicable disease morbidity (4·0 million YLDs in 2019 alone). Three cause groups (enteric infections, lower-respiratory-tract infections, and malaria) accounted for 59·8% of the global communicable disease burden in children and adolescents, with tuberculosis and HIV both emerging as important causes during adolescence. HIV was the only cause for which disease burden increased over time, particularly in children and adolescents older than 5 years, and especially in females. Excess MIRs for HIV were observed for males aged 15-19 years in low-SDI settings. INTERPRETATION: Our analysis supports continued policy focus on enteric infections and lower-respiratory-tract infections, with orientation to children younger than 5 years in settings of low socioeconomic development. However, efforts should also be targeted to other conditions, particularly HIV, given its increased burden in older children and adolescents. Older children and adolescents also experience a large burden of communicable disease, further highlighting the need for efforts to extend beyond the first 5 years of life. Our analysis also identified substantial morbidity caused by communicable diseases affecting child and adolescent health across the world. FUNDING: The Australian National Health and Medical Research Council Centre for Research Excellence for Driving Investment in Global Adolescent Health and the Bill & Melinda Gates Foundation

Global estimates on the number of people blind or visually impaired by diabetic retinopathy: a meta-analysis from 2000 to 2020

Objectives To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by diabetic retinopathy and their proportion of the total number of vision-impaired individuals. Methods Data from population-based studies on eye diseases between 1980 to 2018 were compiled. Meta-regression models were performed to estimate the prevalence of blindness (presenting visual acuity <3/60) and moderate or severe vision impairment (MSVI; <6/18 to ≥3/60) attributed to DR. The estimates, with 95% uncertainty intervals [UIs], were stratified by age, sex, year, and region. Results In 2020, 1.07 million (95% UI: 0.76, 1.51) people were blind due to DR, with nearly 3.28 million (95% UI: 2.41, 4.34) experiencing MSVI. The GBD super-regions with the highest percentage of all DR-related blindness and MSVI were Latin America and the Caribbean (6.95% [95% UI: 5.08, 9.51]) and North Africa and the Middle East (2.12% [95% UI: 1.55, 2.79]), respectively. Between 2000 and 2020, changes in DR-related blindness and MSVI were greater among females than males, predominantly in the super-regions of South Asia (blindness) and Southeast Asia, East Asia, and Oceania (MSVI). Conclusions Given the rapid global rise in diabetes and increased life expectancy, DR is anticipated to persist as a significant public health challenge. The findings emphasise the need for gender-specific interventions and region-specific DR healthcare policies to mitigate disparities and prevent avoidable blindness. This study contributes to the expanding body of literature on the burden of DR, highlighting the need for increased global attention and investment in this research area.publishedVersio