bluuebunny/crossref_metadata_2025 huggingface dataset:
Strength and Durability Studies on Hybrid Fiber Reinforced High-Performance Concrete for Silica Fume Based Mineral Admixture
Authors: Adanagouda  , Somasekharaiah H.M.
Published: August 2021

This study aims to investigate the strength and durability studies on Hybrid fibers reinforced High-Performance Concrete for Silica fume (SF) based mineral admixture. A constant proportion of 0.25% for polypropylene fibers (PF) and varying proportions of 0%, 0.5%, 0.75% and 1.0% for crimped steel fibers (CF) making a total fiber volume fractions of 0%, 0.75%, 1.0% and 1.25% were used to develop hybrid fiber-reinforced high-performance concrete (HFRHPC). Four replacement levels for hybrid fibers by volume of the binders and four partial replacement levels for Silica fume (0%, 10%, 20% & 30%) by weight of cement have been considered for three different water binder ratios (0.275, 0.325 & 0.375). An aggregate binder ratio of 1.75 was kept constant. The test results reveal a maximum increase of 35.18%, 40.35%, and 71.54% in compressive strength, split tensile strength, and flexural strength, respectively, for a curing period of 28 days. Acid attack tests have been conducted to measure the durability of HFRHPC. Cubes of 100x100x00mm have been cast, cured, and then kept immersed in 5% concentrated solutions of Hydrochloric acid (HCL), Magnesium sulphate (MgSO4), and Sulphuric acid ( H2SO4) for 30,60 and 90 days and then tested to record the residual compressive strength of HFRHPC produced with the Silica fume mineral admixtures. The results have been analyzed, and valid conclusions have been drawn. The results indicate that a combination of 1.25% hybrid fibers and 10% Silica fume mineral admixture gains all the water-binder ratios’ highest strength.
Ternary Blended Geo-Polymer Concrete – A Review
Authors: Khalid S Md , Shobha M S , Tanu H M , Reshma T V
Published: August 2021

The manufacturing of ordinary Portland cement produces carbon di oxide which is responsible for global warming. Geopolymer concrete in the field of construction leads to economic sustainability and reduces adverse effects on environment. Geopolymers are inorganic polymers obtained from chemical reaction between an alkaline activator’s solution and an alumina-silicate material without using cement. Alkali activators are Homogeneous mixture consisting of two (NaOH and Na2SO3) or more chemicals in different proportions are highly corrosive and difficult to handle. There are still some limitations with respect to the alkaline activators in geopolymer concrete. To overcome ordinary portland cement, many wastes materials such as Silica-fume, GGBS, fly ash etc. have been used in recent studies to create eco-friendly cements by geo-polymerization reactions. Geopolymers are economic & good alternative construction material in making concrete This review paper briefly explains on previous literatures, properties, materials of geopolymer concrete, testing and practical applications of geopolymer concrete.
Static and modal analysis of sine-wave-shaped spar
Authors: Elshazly E , Kassem M , Elshafei M A , Kamel M
Published: August 2021

Sine-Wave-shaped Spar (SWS) is recently involved in wing design as one of the corrugated shaped spars that highly improve the torsion and buckling resistance. SWS is an I-beam made of sine wave shaped vertical web fixed to upper and lower flanges. The current research evaluates the behavior of SWS in comparison to the traditional straight-web spar in resisting two cases of loading; static bending loading and static torsion loading. For each case, deformation and stress are analyzed. Modal analysis is also performed for the two spar configurations. For this purpose, a finite element model is developed using Ansys Workbench software for the SWS and the straight web spar. To reach a fair comparison, similar weight is considered for the two spar structures. A parametric study is performed to investigate the effect of web thickness and flange thickness on the bending and torsion deformation and stresses. The effect of thickness variation on the natural frequencies and mode shapes is also considered. The current study can be considered a base to design wing spars that combine the merits of the two spar configurations.
Numerical simulation of temperature field in a C/C composite multidisk brake during aircraft braking
Authors: Ramadan E M , Hussien A E , Youssef A M , El-Badia T M Abd
Published: August 2021

This article presents a finite element method for simulating the heat production during stopping the aircraft. Thermal analysis and simulation in the finite element model are based on the theory of energy transformation and transportation. A commercial software COMSOL Multiphysics 5.5a is used for simulating the braking operation. The internal temperatures of the brake disks were obtained and the variation in temperatures between disks were discussed. Thermomechanical behaviour is studied to show the effect of thermal energy on the contact mechanics for the friction surfaces between the brake disks. Aircraft mass, initial velocity and deceleration rate are responsible for heat generation and consequently the maximum reached temperature during braking. The friction surfaces between disks were the main heat energy source where the heat was concentrating on these layers of friction surfaces. For the selected braking operation, the maximum reached temperature was 1020K. The finite element model was validated against historical data for a Boeing737-400 at constant deceleration for new disk brakes and for RTO brake energy.
Design of a smart energy efficient IoT wireless node
Authors: Nabil M S , Tammamand A F , ElKhatib M M
Published: August 2021

The Internet of Things (IoT) is gaining greater effect in our life from day to day. Wireless sensor networks (WSN) are embedded into the “Internet of Things” and power saving is one of the problems that it faces. This study introduces a new circuit design for a DC-DC Buck-Boost converter for controlling the output voltage of Energy Harvester (EH) via adaptive Neuro-Fuzzy inference systems (ANFIS) controller. It has proven that there is an effective changes regarding settling time almost being zero, overshoot being negligible and steady state voltage. As an application for the proposed design, an implementation for Precision Agriculture (PA) self-sustainable Wireless Sensor-Node (WS-N) with low power consumption has been presented. A solar power management for Precision agricultural in internet of things system proved to enhance cost-efficiency and increased lifetime for the device. The simulation results are determined by means that of MATLAB/Simulink software. The cloud service of Blynk IoT has been implemented to monitor the collected data on real time. Data on solar cells, batteries and soil were regarded reliable and precise.
Comparative study between cognitive radio techniques in FM broadcasting band
Authors: Hamed I , Elmenyawi M A , Hassan A Y
Published: August 2021

Optimum usage of the existing frequency spectrum is a major requirement due to the large increase in the number of subscribers at the same frequency. The cognitive radio scheme has become an important application used to optimize spectrum utilization, detects spectrum bands that are not occupied by primary users to create communication links between secondary users in the same band. These non-occupied bands are described as white space. In this paper, a spectrum sensing method that is an important stage in cognitive radio communications is discussed. Various spectrum sensing methods such as energy detection (ED) and cyclostationary feature detection (CFD) are used to sense the spectrum in the FM broadcasting band. A comparison of energy detection and cyclostationary feature detection spectrum sensing methods is made to determine the empty bands in the FM broadcasting band. This enables secondary users to transfer information in these empty bands without affecting the primary users of the FM broadcasting system.
Enhanced image encryption algorithm by quantum key distribution
Authors: Mahmoud M A , Mekkawy T , Elbayoumy A D
Published: August 2021

Quantum Key Distribution (QKD) is one type of Quantum Cryptography (QC) which is based on quantum mechanics fundamentals such as Heisenberg’s uncertainty principle and No-cloning theory. The usage of QKD warns the legitimate communicated parties to any attack attempt and this is the most interesting security parameter. Therefore, QKD provides unconditional secure communication method and supports a powerful encryption scheme. The combination between classical communication and QKD creates a new technique called semi quantum key distribution SQKD. Unfortunately, SQKD increases the schemes complexity and requires two steps for ciphering, scramble and encryption. In this paper an enhance image encryption algorithm is proposed based on QKD that eliminates most of the drawbacks of SQKD. The proposed algorithm is simpler than other encryption schemes as it exploits only one encryption step based on the power and the randomness of the generated secret key, which decreases the chance to be cracked. The correctness and efficiency of the proposed algorithm are validated by numerical simulations.
Assessment of top of atmosphere reflectance generation algorithm for world view-2 high resolution images
Authors: Allam M , Mahmoud T , Elsharkawy A , Sheta B
Published: August 2021

Recently, there are many developments in remote sensing techniques using satellite imagery as a result of the variety of remotely sensed image sources with different spatial and spectral resolutions and from different sensors. Optical satellite products are affected by an error of payload, atmosphere (scattering and absorption), and variations relative to positions of Sun, Earth, and satellite during capturing data. Top of Atmosphere (TOA) correction is the process of removing the effects of variations relative to sensor error and positions of Sun, Earth, and satellite. In this paper, maximum benefits from high spectral and spatial resolution images are demonstrated and analyzed or compared with images from different. TOA correction algorithm, which was implemented using Python environment, is applied to high resolution images from WorldView-2 (WV-2) satellite. TOA reflectance is considered the first step in any algorithm dedicated to the change detection process. Reflectance conversion is also performed on the same images using Orfeo ToolBox (OTB), the open-source software. The performance and efficiency of the proposed algorithm are compared with that of the Orfeo ToolBox (OTB) TOA reflectance output. The achieved results show that the proposed algorithm, which is automatically performed, is faster and provides significant results for WV-2 images, and can be adapted to be applied on different optical satellite sensors.
Non-destructive aerial and terrestrial analysis of uranium isotopic activity by sensitive α-spectrometer for El-Sella site
Authors: Sabry M , Omar A , Abdel-Rahman M A , El-Mongy S A
Published: August 2021

Any comprehensive radioactivity surveillance for a specific site should be carried out by a sensitive airborne system (e.g. carried on aircraft) together with terrestrial sampling and analysis. In the framework of ore, environmental and nuclear materials monitoring and investigation, the activity and isotopic compositions signature are considered crucial factors that must be considered, determined and evaluated. In this work and based on previous aerial monitoring, a very sensitive hyper pure germanium detector (Hp-Ge) of 50% efficiency with the Genie 2000 software has been used for spectroscopic non-destructive assay (NDA) of radioactivity content for samples collected from the Egyptian eastern desert (El-Sella Site). The identification of specific signature isotopes through their characteristic gamma lines and a calculation of their specific activities, activity ratios of 235U/238U and 234U/238U and mathematically estimation of the natural enrichment percentage are very vital and nuclear forensic targets. The results of measurements, analysis and calculations show that the Site samples have high radioactivity, natural enrichment origin and high uranium concentration. The obtained results are given tabulated, depicted, discussed and compared with the recent nationally published work and the international levels and limits.
On the unsteady behaviours of the adiabatic endwall film cooling effectiveness
Authors: Qenawy M , Liu Y , Zhou W
Published: August 2021

The film cooling technique is introduced in modern gas turbines to protect the blade from the high temperature of the incoming hot gases by forming a thin coolant blank over the blade surface. However, it is known as a jet in crossflow (JICF), where coolant and mainstream interact intensively and generate complex vortices leading to highly unsteady coolant coverage over the blades surface. In this study, a fast-response pressure-sensitive paint technique (fast-PSP) was used to measure the coolant unsteadiness with a high-resolution camera. The measurements were performed in a novel single-passage transonic wind tunnel to uncover the unsteady effectiveness of the endwall surface. Such effectiveness was dramatically influenced by the blowing ratios (M), showing attached flow at a low blowing ratio and lift-off at a high blowing ratio. The effectiveness was asymmetrically distributed due to the pressure gradients, jet compounding angle, and associated complex flows. The unsteady effectiveness was highly influenced by the energetic vortical structures, which interacted with the mainstream flow immediately behind the holes. It was featured by secondary structures (horseshoe, passage, and counter vortices) beside the JICF structures. Meanwhile, the unsteadiness was originated from the middle of the passage behind the holes. It is suggested to pay close attention to the locations of the holes for further optimization. This study could help the designers to understand the characteristics of unsteady effectiveness, promoting advanced cooling strategies for enhanced protection of future gas turbines.
Modeling, simulation and controller design for a typical bent axis electrohydraulic servo motor
Authors: Yousef M A , El-Sanabawy M , Rabie G , Rateb R A
Published: August 2021

Bent axis electrohydraulic servo motors are one of the Electrohydraulic Servo Motors (EHSMs) family which are used in high frequency, speed, and precision applications such as aerospace applications as well as many military weapon system applications. Therefore, it is essential to understand how such motors affect the whole performance of the system which makes modeling of these motors is an important task to be achieved. Once an accurate model is obtained, an optimum controller can be applied. This paper introduces detailed mathematical modeling of a typical bent axis (EHSM). MATLAB SIMULINK package is used to simulate and control such (EHSM) using PID controller. The PID controller gains were tuned using PD-PI controller to obtain the precision response for the (EHSM). The validity of mathematical modeling was reviewed through some practical experiments.
PID tuning approaches for quadrotors unmanned aerial vehicles
Authors: Mahfouz M , Taiomour A , Ashry M M , Elnashar G
Published: August 2021

In this paper, a comparative study between different PID tunning techniques is presented. The proposed techniques are applied to solve the formation configuration problem for a cooperative team of unmanned vehicles. The formation problem for the cooperative team is divided into two levels of control, one is the backstepping control technique for the stabilization of the team members positions as a higher controller. Simultaneously, PID controller receives the desired position to stabilize the attitude control as a lower controller to track the desired planning trajectories. The main contribution of this paper is the comparison between the different control approaches in tunning the PID gains to stabilize attitude control for the leader quadrotor. Simulation results present the assessment of the proposed PID control technique compared with different PID tuning approaches such as local optimal control, fraction order, Ziegler-Nichols and genetic algorithm. Moreover, disturbance rejection and white noise attenuation criterions are inspected to evaluate the ability of the proposed controllers to preserve the stability of the system.
Design, test and build of a monopropellant thruster using 85% hydrogen peroxide
Authors: Deif A , El-S Makled A , Khalil M K , Elshaar Y
Published: August 2021

The objective of this research is to design, build, and test about a 5N Hydrogen Peroxide(H2O2) monopropellant thruster (MPT). It is utilized in remote sensing satellites for attitude control and orbit manoeuvres. The MPT uses high test peroxide (HTP) of 85 % concentration. Firstly, H2O2 ≈85% concertation by weight is prepared in the laboratory. A distillation and filtration units are built. The distillation and filtration processes are performed. Next, the design of the monopropellant thruster is done based on the developed mathematical model using NASA CEA rocket performance code. The test facility is developed which consists of the thruster, the feeding system, static test stand and data acquisition system with measuring sensors. An experimental test stand is designed and fabricated with Pendulum thrust mechanism for measurements of thrust. Finally, the silver catalyst is prepared and packed inside the MPT chamber where silver screens of high purity 99.96 % are used. The 10-firing tests are conducted under atmospheric conditions. The firings performed without heating are not completely successful. The analysis of the results shows that the thruster has a thrust range from 3.8-4.2 N. The performance of thruster starts to decay after consuming 6 kg of stabilized H2O2. The specific impulse (Is) is evaluated to be ≈93-97s at decomposition pressure of ≈10 bars and mass flow rate conf≈4.18 g/s. The performance evaluation is judged to be successful. However, using the whole potential of the 85% concentrated H2O2, is expected to increase (Is) up to ≈111.5s.
Effects of post heat treatment on the microstructure evolution of Inconel 718 manufactured by selective laser melting
Authors: Song Tao , Xue Zhixiang , Ma Guanbing , Chen Yang , Yuan Shuxian , Li Chenglin , Hu Yangsen , Zhang Jun
Published: August 2021

In this work, the microstructure, precipitations, crystal orientation and texture of an Inconel 718 superalloy manufactured by selective laser melting (SLM) are investigated by performing post heat treatment. Horizontal and vertical reference faces are examined in the as-built condition, solution conditions for 0.5 and 1 h, and aging condition, respectively. In the as-built condition, Inconel 718 superalloy exhibited cellular and columnar dendrites, a large amount of the fine Laves phase, and several γ′ phases. During post treatment, the grain size on the horizontal face is changed, which is ranged from 502.23 to 523.55 μm2 per grain. Meanwhile, grains coarsened distinctly on the vertical face. The average area of the grain is 739.48 μm2 in the as-built condition and increases to 898.19 μm2 in the aging condition. Additionally, the amount of MC carbides, γ′, and γ″ strengthening phases increased as well during the post heat treatment process, while that of the Laves phase decreased after solution treatment. The preferred orientation on the horizontal face was 〈111〉//X, 〈001〉//Y in the as-built condition, and 〈101〉//Z in the solution and aging conditions. The preferred orientation on the vertical face was 〈001〉//X, 〈101〉//Y in the as-built condition, 〈101〉//Y in the solution condition, and 〈001〉//X in the aging condition. The orientation distribution function (ODF) analysis showed that the main textures in the as-built and solution conditions were {110}〈110〉 and {110}〈112〉, respectively, which transformed to {001}〈100〉 and {001}〈110〉 during aging. The values of multiples of uniform density (mud) in both horizontal and vertical reference faces the aforementioned preferred orientation and texture increased during post heat treatment. Application of post heat treatment can lead to an ideal microstructure Inconel 718 superalloy manufactured by SLM.
The Final Chapter of the Demise of the Pure Absolute Doctrine of State Immunity in English Law: A Swedish vignette
Authors: Beatson Jack
Published: August 2021

A comment on the insight Johnny Veeder’s historical sense and the insight he derived from his research in archives gave him in understanding the final chapter of the story of the demise in the common law of the UK of the pure, absolute, doctrine of state or sovereign immunity in the I Congreso del Partido
Swords into Plowshares: A Pilgrimage for the CSS Alabama
Authors: Park William W
Published: August 2021

During the American Civil War, Britain sold ships to the Southern Confederacy in breach of neutrality obligations, triggering a dispute with the United States carrying threats of armed conflict. Some American politicians saw the dispute as an opportunity to annex Canada, then a weak assemblage of British colonies. Ultimately, arbitration in Geneva averted war, opening an era of long Anglo-American cooperation. The historical consequence of this landmark 1872 arbitration remains difficult to overstate. In addition to its diplomatic importance, the case introduced significant procedural precedents for international arbitration, including dissenting options, reasoned awards, party-appointed arbitrators, collegial deliberations, and arbitrators’ declarations on their own jurisdiction. The saga of the CSS Alabama, the vessel from which the arbitration took its name, provides a narrative as griping in detail as the arbitral proceedings prove meaningful in legal legacy.
Functional network topology in drug resistant and well-controlled idiopathic generalized epilepsy: a resting state functional MRI study
Authors: Pegg Emily J , McKavanagh Andrea , Bracewell R Martyn , Chen Yachin , Das Kumar , Denby Christine , Kreilkamp Barbara A K , Laiou Petroula , Marson Anthony , Mohanraj Rajiv , Taylor Jason R , Keller Simon S
Published: August 2021

Despite an increasing number of drug treatment options for people with idiopathic generalized epilepsy (IGE), drug resistance remains a significant issue and the mechanisms underlying it remain poorly understood. Previous studies have largely focused on potential cellular or genetic explanations for drug resistance. However, epilepsy is understood to be a network disorder and there is a growing body of literature suggesting altered topology of large-scale resting networks in people with epilepsy compared with controls. We hypothesize that network alterations may also play a role in seizure control. The aim of this study was to compare resting state functional network structure between well-controlled IGE (WC-IGE), drug resistant IGE (DR-IGE) and healthy controls. Thirty-three participants with IGE (10 with WC-IGE and 23 with DR-IGE) and 34 controls were included. Resting state functional MRI networks were constructed using the Functional Connectivity Toolbox (CONN). Global graph theoretic network measures of average node strength (an equivalent measure to mean degree in a network that is fully connected), node strength distribution variance, characteristic path length, average clustering coefficient, small-world index and average betweenness centrality were computed. Graphs were constructed separately for positively weighted connections and for absolute values. Individual nodal values of strength and betweenness centrality were also measured and ‘hub nodes’ were compared between groups. Outcome measures were assessed across the three groups and between both groups with IGE and controls. The IGE group as a whole had a higher average node strength, characteristic path length and average betweenness centrality. There were no clear differences between groups according to seizure control. Outcome metrics were sensitive to whether negatively correlated connections were included in network construction. There were no clear differences in the location of ‘hub nodes’ between groups. The results suggest that, irrespective of seizure control, IGE interictal network topology is more regular and has a higher global connectivity compared to controls, with no alteration in hub node locations. These alterations may produce a resting state network that is more vulnerable to transitioning to the seizure state. It is possible that the lack of apparent influence of seizure control on network topology is limited by challenges in classifying drug response. It is also demonstrated that network topological features are influenced by the sign of connectivity weights and therefore future methodological work is warranted to account for anticorrelations in graph theoretic studies.
Role of caveolin-1 in human organ function and disease: friend or foe?
Authors: Pang Liwei , Yang Shaojie , Dai Wanlin , Wu Shuodong , Kong Jing
Published: August 2021

Caveolin-1 (Cav-1) is a structural protein component of caveolae, which are invaginations of the plasma membrane involved in various cellular processes, including endocytosis, extracellular matrix organization, cholesterol distribution, cell migration and signaling. Mounting evidence over the last 10–15 years has demonstrated a central role of Cav-1 in many diseases, such as cancer, diabetes and fibrosis. Cav-1 plays positive and negative roles in various diseases through its different regulation pathways. Here, we review the current knowledge on Cav-1 in different diseases and discuss the role of this protein in human organs and diseases.
An introduction to inverse probability of treatment weighting in observational research
Authors: Chesnaye Nicholas C , Stel Vianda S , Tripepi Giovanni , Dekker Friedo W , Fu Edouard L , Zoccali Carmine , Jager Kitty J
Published: August 2021

In this article we introduce the concept of inverse probability of treatment weighting (IPTW) and describe how this method can be applied to adjust for measured confounding in observational research, illustrated by a clinical example from nephrology. IPTW involves two main steps. First, the probability—or propensity—of being exposed to the risk factor or intervention of interest is calculated, given an individual’s characteristics (i.e. propensity score). Second, weights are calculated as the inverse of the propensity score. The application of these weights to the study population creates a pseudopopulation in which confounders are equally distributed across exposed and unexposed groups. We also elaborate on how weighting can be applied in longitudinal studies to deal with informative censoring and time-dependent confounding in the setting of treatment-confounder feedback.
Psychological Features in the Inflammatory Bowel Disease–Irritable Bowel Syndrome Overlap: Developing a Preliminary Understanding of Cognitive and Behavioral Factors
Authors: Petrik Megan , Palmer Brooke , Khoruts Alexander , Vaughn Byron
Published: August 2021

Background

Inflammatory bowel disease (IBD) patients in clinical remission may experience ongoing symptoms, such as diarrhea and abdominal pain, attributed to IBD–irritable bowel syndrome (IBS) overlap. This study aims to characterize the psychosocial needs of patients with IBD–IBS overlap, particularly in regard to cognitive and behavioral functioning.

Methods

Adults with an established IBD diagnosis were recruited from a gastroenterology clinic. Participants completed self-report questionnaires about psychological functioning and quality of life. The Rome IV Diagnostic Questionnaire for Adults-IBS Module assessed IBS criteria. The treating gastroenterologist completed a clinician rating of IBD activity to determine clinical disease activity. Biomarkers of inflammation collected in routine care within 90 days of the research encounter were obtained via medical record review to further contextualize IBD activity status. Participants were separated into the following groups: “inactive IBD” (IBD activity rating indicating inactive disease and no IBS criteria met), “active IBD” (IBD activity rating indicating mild, moderate, or severe regardless of IBS criteria), or “IBD–IBS overlap” (IBD activity rating indicating inactive disease and IBS criteria met).

Results

One hundred and seventeen participants were recruited. Those with IBD–IBS overlap reported no significant differences in ratings of anxiety, depression, somatization, catastrophic thinking patterns, and behavioral avoidance, to patients with active IBD whereas participants with inactive IBD reported significantly lower ratings on these factors. However, a significant portion of participants with IBD–IBS overlap who were rated as inactive on IBD activity measures had laboratory or endoscopic findings indicating mild inflammation within 90 days of the research encounter.

Conclusions

The study findings provide preliminary evidence that suggests patients with IBD–IBS overlap display similar rates of psychological distress, catastrophic thinking, and avoidance behaviors as those with active IBD. Those with mild ongoing inflammation despite meeting a definition for clinical remission may have similar psychological needs compared to those with moderate-to-severely active IBD. Incorporating a mental health provider with training in psychogastroenterology can help a patient with IBD learn how to effectively with these cognitive and behavioral patterns.
The Limited Scope of the Democratic Peace: What We Are Missing
Authors: Owsiak Andrew P , Vasquez John A
Published: August 2021

The democratic peace program arguably constitutes one of the most successful empirical research programs in the discipline. Its main empirical finding motivated extensive theorizing (e.g., challengers, as well as distinct theoretical enterprises), sparked further debate about how to conceptualize and operationalize democracy, and shifted the foreign policy discourse, particularly in the United States. Lost in these successes, however, is a critical unanswered question: how much interstate peace can the democratic peace potentially explain? We explore these limits (i.e., scope, or empirical coverage) in this study. We first identify the peaceful dyadic relationships—namely those that never go to war across long historical periods. We next classify these dyads as democratic (i.e., both members are democracies) or nondemocratic. The empirical analysis then examines this democracy–peace relationship across three time periods, three distinct samples (which address potential false positives), two definitions of “peace,” and two thresholds for democracy. Regardless of how we approach the data, only 4–26 percent of all peaceful dyads qualify as “democratic.” Because we control for the obvious trivial explanation (insufficient capabilities due to distance), some other (set of) factor(s) must account for the majority of interstate peace. We close with a discussion about where future research might search for these factors, as well as the larger policy implications of the study.
Antidiabetic Drug Approved to Reduce Risk of Kidney Disease
Authors: Aschenbrenner Diane S.
Published: August 2021

Dapagliflozin (Farxiga) is now approved to reduce the risk of declining kidney function, kidney failure, cardiovascular death, and hospitalization for heart failure in adults with chronic kidney disease with or without type 2 diabetes.
Preventing Violence to Achieve Peaceful and Inclusive Societies
Authors: Cipriano Pamela F. , Blanchard Katie Ann , Rosa William E.
Published: August 2021

This article is one in a series in which contributing authors discuss how the United Nations (UN) Sustainable Development Goals (SDGs) are linked to everyday clinical issues; national public health emergencies; and other nursing issues, such as leadership, shared governance, and advocacy. The 2030 Agenda for Sustainable Development, a 15-year plan of action to achieve the goals, was unanimously adopted by all UN member states in September 2015 and took effect on January 1, 2016. The Agenda consists of 17 SDGs addressing social, economic, and environmental determinants of health and 169 associated targets focused on five themes: people, planet, peace, prosperity, and partnership. The SDGs build on the work of the UN Millennium Development Goals, which were in effect from 2000 to 2015. The current article highlights SDG 16: “Promote peaceful and inclusive societies for sustainable development, provide access to justice for all, and build effective, accountable, and inclusive institutions at all levels.”
Florence Nightingale as an Applied Statistician
Authors: Hassmiller Susan B.
Published: August 2021

Updated several times a week with posts by a wide variety of authors, AJN's blog Off the Charts allows us to provide more timely—and often more personal—perspectives on professional, policy, and clinical issues. Best of the Blog is a regular column to draw the attention of AJN readers to posts we think deserve a wider audience. To read more, please visit: www.ajnoffthecharts.com.
Incidence and Diagnostic Challenges of Bowel Ischemia after Continuous-flow Left Ventricular Assist Device Therapy
Authors: Choi Ashley Y. , Anand Jatin , Bishawi Muath , Halpern Samantha E. , Contreras Fabian J. , Mendiola Michelle A. , Daneshmand Mani A. , Schroder Jacob N. , Vatsaas Cory , Agarwal Suresh M. , Milano Carmelo A.
Published: August 2021

Long-term continuous-flow left ventricular assist device (CFLVAD) therapy is limited by complications. Compared with stroke and renal dysfunction, post-CFLVAD bowel ischemia is poorly characterized. Adult patients who underwent first-time durable CFLVAD implantation at our institution between 2008 and 2018 were identified and screened for bowel ischemia using Current Procedural Terminology codes for abdominal surgical exploration and International Classification of Disease codes for intestinal vascular insufficiency. Patients who developed biopsy-proven bowel ischemia (cases) were matched to controls (1:1, nearest neighbor, caliper = 0.29) based on preoperative characteristics. Incidences of postoperative right heart failure and renal replacement therapy were compared using McNemar’s test. One year survival was estimated using the Kaplan-Meier method. Overall, 711 patients underwent CFLVAD implantation. Nineteen (2.7%) developed bowel ischemia (cases) median 17 days postimplantation (IQR 8–71). The majority of cases were male (78.9%), Black (63.2%), received HeartMate II (57.9%), treated as destination therapy (78.9%), and had a history of hypertension (89.5%), chronic kidney disease (84.2%), hyperlipidemia (84.2%), smoking (78.9%), and atrial fibrillation (57.9%). Post-LVAD, case patients were more likely to develop moderate-severe right heart failure (89.5% vs. 68.4%, p = 0.005), require renal replacement therapy (21.1% vs. 0%, p < 0.001), and less likely to survive to discharge (52.6% vs. 89.5%, p = 0.02) compared with controls. Case subjects demonstrated worse 1 year survival. While less common than stroke and renal dysfunction, post-CFLVAD bowel ischemia is associated with high 1 year mortality. Multi-institutional registries should consider reporting abdominal complications such as bowel ischemia as an adverse event to further investigate these trends and identify predictors of this complication to reduce patient mortality.
Case Report: Subconjunctival Triamcinolone Acetate–associated Scleral Necrosis: Is It Really Obsolete?
Authors: Agarwal Rinky , Bafna Rahul Kumar , Chetan Chetan , Sharma Namrata
Published: August 2021

SIGNIFICANCE

Recent studies have established the safety of subconjunctival steroids for anterior scleritis, refuting scleral necrosis as a potential complication. However, presently, we report a rare case of scleral necrosis associated with subconjunctival triamcinolone acetate.

PURPOSE

The purpose of this study was to report a case of scleral necrosis after subconjunctival triamcinolone acetate administration for nonresponsive anterior nodular scleritis.

CASE REPORT

A 45-year-old man diagnosed with nodular anterior scleritis was administered subconjunctival triamcinolone acetate (4 mg) adjacent to the nodule after noting nonresponse for 4 months. Worsening of congestion was noted 3 weeks after the injection. Slit-lamp examination revealed diffuse congestion, 10 clock hours of anterior scleral necrosis, superior whitish depot of subconjunctival triamcinolone acetate, anterior segment flare, and few posterior synechiae. Ultrasound biomicroscopic imaging and contrast-enhanced computerized tomography showed a localized outpouching of sclera and buckling of anterior scleral wall superiorly. The result of the comprehensive blood profile and systemic evaluation undertaken to rule out any underlying autoimmune disorders and herpes zoster ophthalmicus was found negative. A diagnosis of subconjunctival triamcinolone acetate–associated scleral necrosis was made, and the patient was managed conservatively. Gradual improvement with dissolution of subconjunctival triamcinolone acetate and no recurrences till 2 years of follow-up were noted.

CONCLUSIONS

Scleral necrosis is a potential complication of subconjunctival triamcinolone acetate. Judicious and cautious use of subconjunctival triamcinolone acetate is advocated for nonresolving anterior scleritis.
Devosia beringensis sp. nov., isolated from surface sediment of the Bering Sea
Authors: Zhang Yu-Xin , Yu Yong , Luo Wei , Zeng Yin-Xin , Du Zong-Jun , Li Hui-Rong
Published: August 2021

Strain S02T was isolated from a surface sediment sample collected from the Bering Sea (64.3361° N, 170.9541° W). The cells were Gram-stain-negative, motile and rod-shaped. The temperature range for growth was 4–25 °C and the pH for growth was 5.5–9.0, with optimum growth occurring at 20–25 °C and pH 7.0–8.0. Growth occurred in the presence of 0–7 % (w/v) NaCl (optimum, 2–5 %). Strain S02T had menaquinone-8 as the major respiratory quinone and summed feature 8 (C18 : 1
 ω7c and/or C18 : 1
 ω6c), C16:0, C17 : 0 cyclo, summed feature 3 (C16 : 1
 ω7c /C16 : 1
 ω7c), C17 : 0 and C18 : 0 as major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and two glycolipids. The genomic DNA G+C content was approximately 63.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S02T belonged to the genus

Devosia

. Strain S02T showed the highest sequence similarities to

Devosia psychrophila

Cr7-05T (97.5 %),

Devosia naphthalenivorans

CM5-1T (97.7 %),

Devosia submarina

KMM 9415T (97.4 %),

Devosia epidermidihirudinis

E84T (97.44 %),

Devosia euplotis

LIV5T (97.1 %) and

Devosia limi

DSM 17137T (96.7 %). On the basis of phylogenetic analyses and phenotypic characteristics, a novel species of the genus

Devosia

, Devosia beringensis sp. nov., is proposed, with the type strain S02T (=JCM 33772=CCTCC AB 2019343).
Comparative analyses of FDA EUA-approved rapid antigen tests and RT-PCR for COVID-19 quarantine and surveillance-based isolation
Authors: Wells Chad R. , Pandey Abhishek , Moghadas Seyed M. , Singer Burton H. , Krieger Gary , Heron Richard J.L. , Turner David E. , Abshire Justin P. , Phillips Kimberly M. , Michael Donoghue A. , Galvani Alison P. , Townsend Jeffrey P.
Published: August 2021

Background

Rapid antigen (RA) tests are being increasingly employed to detect SARS-CoV-2 infections in quarantine and surveillance. Prior research has focused on RT-PCR testing, a single RA test, or generic diagnostic characteristics of RA tests in assessing testing strategies.

Methods

For 18 RA tests with emergency use authorization from the United States of America FDA and an RT-PCR test, we conducted a comparative analysis of the post-quarantine transmission, the effective reproduction number during serial testing, and the false-positive rates. To quantify the extent of transmission, we developed an analytical mathematical framework informed by COVID-19 infectiousness, test specificity, and temporal diagnostic sensitivity data.

Results

We demonstrate that the relative effectiveness of RA and RT-PCR tests in reducing post-quarantine transmission depends on the quarantine duration and the turnaround time of testing results. For quarantines of two days or shorter, conducting a RA test on exit from quarantine reduces onward transmission more than a single RT-PCR test (with a 24-h delay) conducted upon exit. Applied to a complementary approach of performing serial testing at a specified frequency paired with isolation of positives, we have shown that RA tests outperform RT-PCR with a 24-h delay. The results from our modeling framework are consistent with quarantine and serial testing data collected from a remote industry setting.

Conclusions

These RA test-specific results are an important component of the tool set for policy decision-making, and demonstrate that judicious selection of an appropriate RA test can supply a viable alternative to RT-PCR in efforts to control the spread of disease.

Plain language summary

Previous research has determined optimal timing for testing in quarantine and the utility of different frequencies of testing for disease surveillance using RT-PCR and generalized rapid antigen tests.

However, these strategies can depend on the specific rapid antigen test used. By examining 18 rapid antigen tests, we demonstrate that a single rapid antigen test performs better than RT-PCR when quarantines are two days or less in duration. In the context of disease surveillance, the ability of a rapid antigen test to provide results quickly counteracts its lower sensitivity with potentially more false positives. These analytical results based on highly controlled test validation were consistent with real-world data obtained from quarantine and serial testing in an industrial setting.
Woodsmoke particulates alter expression of antiviral host response genes in human nasal epithelial cells infected with SARS-CoV-2 in a sex-dependent manner
Authors: Brocke Stephanie A. , Billings Grant T. , Taft-Benz Sharon , Alexis Neil E. , Heise Mark T. , Jaspers Ilona
Published: August 2021

We have previously shown that exposure to particulate air pollution, both from natural and anthropogenic sources, alters gene expression in the airways and increases susceptibility to respiratory viral infection. Additionally, we have shown that woodsmoke particulates (WSP) affect responses to influenza in a sex-dependent manner. In the present study, we used human nasal epithelial cells (hNECs) from both sexes to investigate how particulate exposure could modulate gene expression in the context of SARS-CoV-2 infection. We used diesel exhaust particulate (DEP) as well as WSP derived from eucalyptus or red oak wood. HNECs were exposed to particulates at a concentration of 22 μg/cm2 for 2 h then immediately infected with SARS-CoV-2 at a MOI (multiplicity of infection) of 0.5. Exposure to particulates had no significant effects on viral load recovered from infected cells. Without particulate exposure, hNECs from both sexes displayed a robust upregulation of antiviral host response genes, though the response was greater in males. However, WSP exposure before infection dampened expression of genes related to the antiviral host response by 72 h post infection. Specifically, red oak WSP downregulated IFIT1, IFITM3, IFNB1, MX1, CCL3, CCL5, CXCL11, CXCL10, and DDX58, among others. After sex stratification of these results, we found that exposure to WSP prior to SARS-CoV-2 infection downregulated anti-viral gene expression in hNECs from females more so than males. These data indicate that WSP, specifically from red oak, alter virus-induced gene expression in a sex-dependent manner and potentially suppress antiviral host defense responses following SARS-CoV-2 infection.
Unique spatiotemporal fMRI dynamics in the awake mouse brain
Authors: Atulkumar Singh Neha , Gutierrez-Barragan Daniel , Alvino Filomena , Coletta Ludovico , Rocchi Federico , De Guzman Elizabeth , Galbusera Alberto , Panzeri Stefano , Uboldi Mauro , Gozzi Alessandro
Published: August 2021

Human imaging studies have shown that spontaneous brain activity exhibits stereotypic spatiotemporal reorganization in awake, conscious conditions with respect to minimally conscious states. However, whether and how this phenomenon can be generalized to lower mammalian species, remains unclear. Leveraging a robust protocol for resting-state fMRI (rsfMRI) mapping in non-anesthetized, head-fixed mice, we investigated functional network topography and dynamic structure of spontaneous brain activity in wakeful animals. We found that rsfMRI networks in the awake state, while anatomically comparable to those observed under anesthesia, are topologically configured to maximize interregional communication, departing from the underlying community structure of the mouse axonal connectome. We further report that rsfMRI activity in wakeful animals exhibits unique spatiotemporal dynamics characterized by a state-dependent, dominant occurrence of coactivation patterns encompassing a prominent participation of arousal-related forebrain nuclei, and functional anti-coordination between visual-auditory and polymodal cortical areas. We finally show that rsfMRI dynamics in awake mice exhibits a stereotypical temporal structure, in which state-dominant coactivation patterns are configured as network attractors. These findings suggest that spontaneous brain activity in awake mice is critically shaped by state-specific involvement of basal forebrain arousal systems, and document that its dynamic structure recapitulates distinctive, evolutionarily-relevant principles that are predictive of conscious states in higher mammalian species.
Assembly history modulates vertical root distribution in a grassland experiment
Authors: Alonso-Crespo Inés M. , Weidlich Emanuela W.A. , Temperton Vicky M. , Delory Benjamin M.
Published: August 2021

The order of arrival of plant species during assembly can affect the structure and functioning of grassland communities. These so-called priority effects have been extensively studied aboveground, but we still do not know how they affect the vertical distribution of roots in the soil and the rooting depth of plant communities. To test this hypothesis, we manipulated the order of arrival of three plant functional groups (forbs, grasses and legumes) in a rhizobox experiment. Priority effects were created by sowing one functional group 10 days before the other two. Rhizoboxes in which all functional groups were sown simultaneously were used as controls. During the experiment, the mean rooting depth of plant communities was monitored using image analysis and a new methodological approach using deep learning (RootPainter) for root segmentation. At harvest, we measured aboveground (community and species level) and belowground (community level) biomass, and assessed the vertical distribution of the root biomass in different soil layers. At the community level, all scenarios where one functional group was sown before the other two had similar shoot and root productivity. At the species level, two forbs (Achillea millefoliumandCentaurea jacea) benefited from arriving early, and one legume (Trifolium pratense) had a disadvantage when it was sown after the grasses. Priority effect treatments also affected the vertical distribution of roots. When grasses were sown first, plant communities rooted more shallowly than when forbs or legumes were sown first,. In addition, roots moved down the soil profile 24% more slowly in grasses-first communities. Our results highlight that plant functional group order of arrival in grassland communities can affect the vertical distribution of roots in the soil and this may have implications for species coexistence.