bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulpiride‐induced hyperprolactinaemia increases retinal vasoinhibin and protects against diabetic retinopathy in rats
Authors: Adán‐Castro Elva , Siqueiros‐Márquez Lourdes , Ramírez‐Hernández Gabriela , Díaz‐Lezama Nundehui , Ruíz‐Herrera Xarubet , Núñez Francisco Freinet , Núñez‐Amaro Carlos D. , Robles‐Osorio Ma. Ludivina , Bertsch Thomas , Triebel Jakob , Martínez de la Escalera Gonzalo , Clapp Carmen
Published: January 2022

Excessive vasopermeability and angiogenesis compromise vision in diabetic macular oedema (DME) and diabetic retinopathy (DR). Vasoinhibin is a fragment of the hormone prolactin (PRL) that inhibits diabetes‐induced retinal hypervasopermeability and ischaemia‐induced retinal angiogenesis in rodents. Hyperprolactinaemia generated by the dopamine D2 receptor antagonist, levosulpiride, is associated with higher levels of vasoinhibin in the vitreous of patients with DR, implying a beneficial outcome due to vasoinhibin‐mediated inhibition of retinal vascular alterations. Here, we tested whether hyperprolactinaemia induced by racemic sulpiride increases intraocular vasoinhibin levels and inhibits retinal hypervasopermeability in diabetic rats. Diabetes was generated with streptozotocin and, 4 weeks later, rats were treated for 2 weeks with sulpiride or osmotic minipumps delivering PRL. ELISA, Western blot, and Evans blue assay were used to evaluate serum PRL, retinal vasoinhibin, and retinal vasopermeability, respectively. Hyperprolactinaemia in response to sulpiride or exogenous PRL was associated with increased levels of vasoinhibin in the retina and reduced retinal hypervasopermeability. Furthermore, sulpiride decreased retinal haemorrhages in response to the intravitreal administration of vascular endothelial growth factor (VEGF). Neither sulpiride nor exogenous PRL modified blood glucose levels or bodyweight. We conclude that sulpiride‐induced hyperprolactinaemia inhibits the diabetes‐ and VEGF‐mediated increase in retinal vasopermeability by promoting the intraocular conversion of endogenous PRL to vasoinhibin. These findings support the therapeutic potential of sulpiride and its levorotatory enantiomer, levosulpiride, against DME and DR.
Biologic and targeted therapeutics in vitiligo
Authors: Karagaiah Priyanka , Schwartz Robert A. , Lotti Torello , Wollina Uwe , Grabbe Stephan , Goldust Mohamad
Published: January 2022

Background

Vitiligo is a long‐standing progressive autoimmune disease with depigmented macules/patches with significant psychological morbidity to the patients. From being one of the most poorly understood diseases in the past, there has been a rampant advance in determining the molecular and genetic factors influencing the disease process. More light has been shed on the complex intracellular environment and interplay between innate and adaptive immunity. Numerous cytokines and signaling pathways have been associated with disease pathogenesis in the recent past.

Objective

The aim of this review the efficacy of biologic and targeted therapeutics in vitiligo.

Methods

A detailed literature search was conducted on databases like PubMed, COCHRANE Central, EMBASE and Google Scholar using keywords—“biologics,” “vitiligo,” “treatment,” “repigmentation,” “JAK inhibitors,”, “TNF‐ꭤ inhibitors,” and “IL17/23 inhibitors,” Relevant studies and review articles in English were analyzed in detail and report was written. This article aimed at a comprehensive review of all the biologicals and newer targeted therapeutics tried in vitiligo and their efficacy with an insight into the potential complications arising as a result of the therapy.

Results

Most conventional vitiligo treatment modalities are restricted to generalized nonspecific immunosuppressants like topical and oral corticosteroids, calcineurin inhibitors, phototherapy, and surgical modalities. There have been reports and studies on the usage of biologicals in treating vitiligo. JAK inhibitors have shown good efficacy in vitiligo; however, it lacks substantial evidence in the form of randomized control trials. Similarly, the use of targeted therapeutics in treating vitiligo is substantiated by limited evidence and requires more randomized trials for further evidence.

Conclusion

JAK inhibitors have shown promising results and good tolerability; Adjuvant phototherapy can achieve a superior response compared to monotherapy. Though TNF‐ꭤ has been tried in a few cases, it is best used if vitiligo is present in association with other chronic autoimmune diseases for which it is indicated. More in vitro studies and clinical research are required to understand the pathogenesis clearly, and therapy has to be targeted at specific pathways for a better approach toward vitiligo. Treatment aimed at induction and differentiation of melanocytes may be added to achieve faster repigmentation.
The Stockholm CREAtinine Measurements (SCREAM) project: Fostering improvements in chronic kidney disease care
Authors: Carrero Juan Jesus , Elinder Carl Gustaf
Published: January 2022

SCREAM (Stockholm CREAtinine Measurements project) was initiated in 2010 in collaboration with the healthcare provider of Stockholm County healthcare to quantify potential medication errors, estimate the burden of chronic kidney disease (CKD) and to illustrate the value of incorporating measures of kidney function into the medical decision process. Because most patients are unaware of their CKD and diagnoses are seldom issued, SCREAM took advantage of the commonness of serum/plasma creatinine testing, which can be used to estimate the glomerular filtration rate (eGFR) and classify the stage of CKD severity. SCREAM is periodically updated, and at present contains healthcare information of all residents in Stockholm region during 2006–2019 (about 3 million people), enriched with a broad range of laboratory measurements for those in whom creatinine or albuminuria has been measured (about 1.8 million people). This health information was linked with national administrative and quality registries via the unique personal identification number of each Swedish citizen, conforming the richest characterization in Sweden of the population's journey through health and disease. This review discusses the context of its creation, strengths and weakness, key findings and plans for the future. We summarize our findings related to the burden of CKD in Sweden, its adverse health risks (such as risk of infections, cancer or dementia) and how underlying kidney function alters the risk–benefit ratio of common medications. Results have had clinical impact and demonstrate the importance of population‐based research in the spectrum of clinical research to improve health.
Green firm, brown environment
Authors: Pal Rupayan , Banerjee Prasenjit , Thakkar Pratik , Tanvir Hussain A. M.
Published: January 2022

We develop a theoretical model to examine the implication of a monopolist’s environmental consciousness, which induces it to adopt cleaner technology or to internalize negative environmental externalities of production or both, for the environment. Results show that greater environmental concern of the monopolist may damage the environment more, despite leading to lower emission intensity. This is true regardless of whether consumers value green production or not. This paper also draws implications of technology standard and emission tax as instruments for environmental regulation. This paper provides a theoretical underpinning of therebound effectin production by showing that the voluntary pro‐environmental compliance behavior may not always mitigate the rebound effect. This suggests that a regulator should be cautious while designing regulatory mechanisms.
Blood and Blood: Anti‐retroviral Therapy, Masculinity, and Redemption among Adolescent Boys in the Eastern Cape Province of South Africa
Authors: Gittings Lesley , Colvin Christopher J. , Hodes Rebecca
Published: January 2022

Adolescents living with perinatally acquired HIV are among the first generation in South Africa to grow up with anti‐retroviral therapy and democratic freedoms. In this article, we explore the biosocial lives of adolescent boys and young men living with HIV in the Eastern Cape Province of South Africa. We conducted qualitative research with 36 adolescent boys and young men in 2016‒2018, including life history narratives, semi‐structured interviews, and analysis of health facility files.[masculinity, South Africa, HIV, adolescence]
Citizenship, language tests, and political participation
Authors: Bonotti Matteo , Willoughby Louisa
Published: January 2022

This article critically examines the argument that language testing for citizenship is necessary in order to ensure that naturalized citizens have sufficient language proficiency to participate in democratic life. First, we contend that as they are currently designed, language tests are normally unsuitable to assess the ability of would‐be citizens to participate in the complex linguistic interactions that characterize democratic life. We further claim that if language tests were redesigned in order to meet this challenge, this would unjustly exclude (or exacerbate the exclusion of) many categories of migrants from citizenship, especially humanitarian entrants and adults with low‐level literacy skills. Finally, we argue that language tests and language skills may be unnecessary for political participation, if institutions and social norms are in place which enable speakers of different languages to participate in political life effectively and without fear of prejudice.
Linguistic justice for immigrants
Authors: De Schutter Helder
Published: January 2022

Should speakers of immigrant languages have fewer language rights than members of long‐settled nations? In this article, I argue that the interests of immigrant and native groups are normatively equally recognition‐worthy. Any legitimate differential recognition must follow from the different interests immigrants have in language. I distinguish three categories of immigrants: strictly temporary immigrants, immigrants that have become or are to be citizens and linguistically very wealthy immigrants. The purpose of distinguishing these types is to get a better grasp on the needs and interests of immigrants, by creating sub‐profiles. I argue that the first group is entitled to minimal language recognition. The second group, I argue, should be granted equal consideration of their languageinterests, but that does not necessarily mean equallanguagerecognition. The third group—linguistically very wealthy immigrants such as English‐speaking immigrants—typically outrivals the local population in terms of the fulfilment of their language identity interests. Their language interests warrant the need of integration into the national language(s), not the need for equal language recognition.
Innovative vaccine approaches—a Keystone Symposia report
Authors: Cable Jennifer , Rappuoli Rino , Klemm Elizabeth J. , Kang Gagandeep , Mutreja Ankur , Wright Gavin J. , Pizza Mariagrazia , Castro Sowmya Ajay , Hoffmann Joseph P. , Alter Galit , Carfi Andrea , Pollard Andrew J. , Krammer Florian , Gupta Ravindra K. , Wagner Caroline E. , Machado Viviane , Modjarrad Kayvon , Corey Lawrence , B. Gilbert Peter , Dougan Gordon , Lurie Nicole , Bjorkman Pamela J. , Chiu Christopher , Nemes Elisa , Gordon Stephen B. , Steer Andrew C. , Rudel Thomas , Blish Catherine A. , Sandberg John Tyler , Brennan Kiva , Klugman Keith P. , Stuart Lynda M. , Madhi Shabir A. , Karp Christopher L.
Published: January 2022

The rapid development of COVID‐19 vaccines was the result of decades of research to establish flexible vaccine platforms and understand pathogens with pandemic potential, as well as several novel changes to the vaccine discovery and development processes that partnered industry and governments. And while vaccines offer the potential to drastically improve global health, low‐and‐middle‐income countries around the world often experience reduced access to vaccines and reduced vaccine efficacy. Addressing these issues will require novel vaccine approaches and platforms, deeper insight how vaccines mediate protection, and innovative trial designs and models. On June 28–30, 2021, experts in vaccine research, development, manufacturing, and deployment met virtually for the Keystone eSymposium “Innovative Vaccine Approaches” to discuss advances in vaccine research and development.
Transcranial direct current stimulation in patient with J wave syndrome and implantable cardioverter defibrillator
Authors: Samani Susan , Samimi Sahar , Mollazadeh Reza , Mehrpour Masoud
Published: January 2022

J wave syndrome is a spectrum of proarrhythmic disorders including Brugada syndrome and early repolarization syndrome (ERS), that are prone to ventricular fibrillation and sudden cardiac death (SCD). In this case report we present a patient with ERS and aborted SCD complicated with cognitive impairment. We also investigated whether performing transcranial direct current stimulation to target his cognitive impairment, interfered with the function of his implantable cardioverter defibrillator.
Oxygen saturation targets in pediatric respiratory disease
Authors: Nagakura Akito , Morikawa Yoshihiko , Takasugi Nao , Funakoshi Hanako , Miura Yoko , Ota Tomomi , Shimizu Ayumi , Shimizu Keisuke , Shirane Shoichiro , Hataya Hiroshi
Published: January 2022

Background

The present study aimed to assess the appropriate oxygen saturation target in patients with pediatric respiratory diseases by lowering the oxygen saturation target from SpO2 94% to 90%. No previous study has explored appropriate oxygen saturation targets in respiratory diseases other than bronchiolitis.

Methods

The present, prospective, single‐arm intervention trial enrolled pediatric inpatients with bronchiolitis, bronchitis, pneumonia, and asthma. The oxygen saturation target was lowered from SpO2 94% to 90% after the patients' general condition improved. The patients continued to be observed for 12 h after achieving SpO2 94%. The duration from the first cut‐off point (SpO2 90% for 12 h without oxygen) to the second cut‐off point (SpO2 94% for 12 h) was then evaluated.

Results

In total, 248 patients completed the study. Patients with bronchiolitis, bronchitis, pneumonia, and asthma had an interval between the two cut‐off points of 23.9, 15.5, 19.1, and 13.8 h, respectively, (mean 17.2 h; 95% confidence interval 15.0–19.5).

Conclusions

In generally healthy children, setting the oxygen saturation target at SpO2 90% after confirming improvement in their general condition was safe. The time required for increasing SpO2 from 90% to 94% was longest in the patients with bronchiolitis.
Bi+ adults' daily wellbeing: The roles of relationship status and partner gender
Authors: Vilkin Ellora , Davila Joanne , Dyar Christina , Feinstein Brian A.
Published: January 2022

This study examined whether relationship involvement and partner gender were associated with between‐person differences and within‐person fluctuation in positive and negative affect and alcohol use among people who are attracted to more than one gender or regardless of gender (e.g., bisexual, pansexual, queer; bi+). One hundred and ninety‐eight bi+ individuals (M age 26.97; 73.1% non‐Latinx White) completed a 28‐day diary study. Multilevel regression analyses modeled between‐person differences in daily affect and alcohol use as a function of relationship status and partner gender. ANCOVAs were conducted to examine differences in within‐person fluctuation. Results partially support past findings that relationship involvement may not confer benefits for bi+ people and that mixed‐gender partnerships could be particularly challenging. Future research directions are discussed.
Changes in biochemistry and cellular ultrastructure support different resistance mechanisms to Phytophthora sojae in nonhost common bean and host soybean
Authors: Bi Xiangqi , Song Guangmei , Yu Han , Zhang Zhuoqun , Liu Haixu , Yang Zhiyue , Chen Yufei , Wen Jingzhi
Published: January 2022

Phytophthora root and stem rot of soybean caused by Phytophthora sojae is a destructive disease affecting soybean production worldwide. In nature, soybean is the only economically important cultivated host of P. sojae. The aim of this study was to explain different resistance mechanisms to P. sojae in nonhost common bean and host soybean as a basis for the control of Phytophthora root and stem rot of soybean via nonhost resistance. Observations and measurements of disease resistance‐related variables showed slight differences in structural and biochemical resistance mechanisms between common bean and soybean. P. sojae infection induced a stronger hypersensitive response in nonhost common bean than in host resistant soybean. Moreover, phytoalexin phaseollidin synthesis‐related vestitone reductase gene was extremely highly up‐regulated, and phytoalexin glyceollin synthesis‐related isoflavone reductase gene was slightly less up‐regulated in common bean than in soybean, which resulted in a higher level of phaseollidin and a lower level of glyceollin in common bean. Phaseollidin had stronger inhibitory effects on mycelial growth and oospore formation of P. sojae than glyceollin, and more cell wall depositions and callose accumulated in common bean, which are probably related to the stronger resistance of nonhost common bean to P. sojae.
Progressing the aerospace performance factor toward nonlinear interactions
Authors: Štumbauer Oldřich , Lališ Andrej
Published: January 2022

Evaluation of safety performance remains central to any safety and risk management. Currently, there are very few support tools and methods which allow for quantitative approach in this domain. One of the successful methods available to this end is the Aerospace Performance Factor (APF). The method is based on hierarchical clustering of taxonomy‐based safety performance indicators, using simple and intelligible formula to compute the overall safety performance signal. The work presented in this study deals with one of the APF shortcomings, namely the absence of nonlinear relations among the performance indicators to capture more accurately the risk in the assessed system. It proposes an addition of new decision criteria behind the APF method as part of the application of Analytical Hierarchy Process (AHP), namely the impact of respective performance indicator on other indicators, regardless of their hierarchical structure. This addition leads to relative changes of performance indicators significance, where those with the highest potential for nonlinear interactions among the entire set of performance indicators are emphasized and the change in their weight ultimately leads to changes in the overall APF signal. The study results indicate that the extended APF signal is refined in terms of extremes and it draws more accurate picture about the actual safety performance, eventually supporting better identification of deviations from its acceptable values. The study was experimentally carried out in the aviation with data from the European Central Repository (ECR) originating from United Kingdom during the years 2013–2015 and verified further on data sets from Finland and Denmark.
Comparison between peritoneal dialysis and hemodialysis on kidney function recovery in incident kidney failure: A nationwide cohort study
Authors: Kuo George , Chen Jia‐Jin , Cheng Ya‐Lien , Fan Pei‐Chun , Lee Cheng‐Chia , Chang Chih‐Hsiang
Published: January 2022

Background

Patients with kidney failure who start dialysis have a chance of kidney function recovery. Whether the initial dialysis modality affects the possibility of recovery is not fully understood.

Methods

We included patients diagnosed with kidney failure requiring dialysis during 2001–2013 from the Taiwan National Health Insurance Research Database. We excluded diabetic and elderly patients. Kidney function recovery was defined as not receiving dialysis therapy for longer than 3 months. The primary outcome was kidney function recovery, and the secondary outcome was all‐cause mortality during a 3‐year follow up.

Results

A total of 12,619 patients was eligible for analysis, with 981 received PD and 11,638 received HD. Total 620 patients had kidney function recovery during a 3‐year follow up, which represented 4.9% of the entire cohort. After propensity score matching, the PD groups were more likely to experience kidney function recovery (subdistribution hazard ratio [SHR]: 1.64, 95% confidence interval [CI]: 1.19–2.25). The risk of all‐cause mortality between groups did not significantly differ (hazard ratio [HR]: 1.23, 95% CI: 0.89–1.70).

Conclusion

The study found that in nonelderly, nondiabetic patients who received inadequate predialysis nephrology care before kidney failure, PD is associated with a higher chance of kidney function recovery.
A novel approach to discriminate sedimentary characteristics of deltaic tidal flats with terrestrial laser scanner: Results from a case study
Authors: Wang Jie , Dai Zhijun , Fagherazzi Sergio , Long Chuqi
Published: January 2022

Sediments in deltaic tidal flats regulate physical and chemical processes. Grain‐size distribution plays an important role in determining sediment dynamics and substrate properties. However, it is challenging to quantify large‐scale depositional environments in intertidal flats, due to time‐consuming grain‐size analyses and sparse sedimentary information extracted from scattered sediment samples. In this study, a novel terrestrial laser scanner (TLS) based method was developed to characterize the substrate of an intertidal flat. Surface sediment samples in the Nanhui flats in the Yangtze Delta, China, and the corresponding waveform amplitudes of TLS echoes at fixed sampling sites were collected for a total of 22 months. A negative logarithmic relationship was found between the sediment sand fraction, average grain size, D50, and corrected waveform amplitude of TLS echo in different hydro‐meteorological conditions. The mean of average grain size of five sediment sampling sites along a transect was 58.78 μm when measured by traditional grain‐size analysis, and 49.48 μm when calculated with the proposed logarithmic equation. The mean error at each site was up to 21.77%. The mean error for the sand and silt fraction at each location was as high as 27.28% and 21.75%, respectively. The spatial distribution pattern of TLS‐based average grain size in the entire study area was consistent with the measured pattern with a Root Mean Square Error of 13.83 μm. These errors could be caused by the accuracy of the TLS waveform amplitude correction and by limits of the method in recognizing different substrates. The effects produced by the presence of microphytobenthos (for example, cyanobacterial mats or diatom biofilms) or bedforms have not been investigated and may have affected the results. The TLS‐based grain‐size measurements can rapidly and effectively discriminate sediment characteristics, thus avoiding traditional time‐consuming measurements. It is expected that the TLS‐based method proposed here will have wide applications in shoreline studies, especially in inaccessible tidal flats.
From Precollege to Career: Barriers Facing Historically Marginalized Students and Evidence‐Based Solutions
Authors: Thiem Kelsey C. , Dasgupta Nilanjana
Published: January 2022

Although the United States population is growing increasingly diverse, the diversity within higher education is not keeping pace. Contributing to the underrepresentation of students from historically marginalized groups are a variety of interconnected systemic barriers that prevent students from entering college, from thriving while there, and from persisting through to graduation. Here, we use the stereotype inoculation model as a guiding framework not only to identify these barriers and their psychological effects on students but also to highlight evidence‐based solutions that colleges and universities can implement to lower these barriers. As a function of our chosen model, we focus on features of educational environments that signal a lack of psychological fit among students from historically marginalized groups. Furthermore, we highlight interventions that can be implemented at the institutional level to change the educational environment and make higher education settings more inclusive and equitable.
Impact of COVID‐19 in hematopoietic stem cell transplant recipients: A systematic review and meta‐analysis
Authors: Shahzad Moazzam , Chaudhary Sibgha Gull , Zafar Muhammad U. , Hassan Maha A. , Hussain Ali , Ali Fatima , Anwar Iqra , Ahmed Mamoon , Ahmed Nausheen , Khurana Sharad , Rauf Muhammad A. , Anwar Faiz , Hematti Peiman , Callander Natalie S. , Abhyankar Sunil H. , McGuirk Joseph P. , Mushtaq Muhammad Umair
Published: January 2022

Background

Hematopoietic stem cell transplant (HSCT) recipients are at increased risk of mortality and morbidity with coronavirus disease 2019 (COVID‐19) due to severe immune dysfunction.

Methods

A literature search was performed on PubMed, Cochrane, and Clinical trials.gov from the date of inception to 12/08/2021. We identified 19 original studies reporting data on COVID‐19 in HSCT recipients after screening 292 articles. Data were extracted following preferred reporting items for systematic reviews and meta‐analysis guidelines. Quality evaluation was done using the National Institutes of Health (NIH) quality assessment tool. Inter‐study variance was calculated using Der Simonian–Laird Estimator. Pooled analysis was conducted using MetaXL. A random‐effects model was used to estimate the proportions with 95% confidence intervals (CI).

Results

Of 6711 patients in 19 studies, 2031 HSCT patients with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection were analyzed. The median age of patients was 56.9 (range 1–81.6) years, and 63% patients were men according to 14 studies. The median time from transplant to SARS‐CoV‐2 infection for autologous (auto) and allogeneic (allo) HSCT patients was 23.2 (0.33–350.5) months and 16.4 (0.2–292.7) months, respectively. The median follow‐up time after COVID‐19 diagnosis was 28 (0–262) days. The COVID‐19 mortality rate was 19% (95% CI 0.15–0.24, I2 = 76%, n = 373/2031). The pooled mortality rate was 17% (95% CI 0.12–0.24, I2 = 78%, n = 147/904) in auto‐HSCT patients and 21% (95% CI 0.16–0.25, I2 = 60%, n = 231/1103) in allo‐HSCT patients.

Conclusions

HSCT recipients have a high risk of mortality and clinical complications due to COVID‐19. There is a need for ongoing vigilance, masks, and social distancing, vaccination, and aggressive management of SARS‐CoV‐2 infection in HSCT recipients.
Evaluation of Adhesive Interface Properties in Honeycomb Sandwich Structure Using Guided Waves
Authors: Negi Parambeer Singh , Koodalil Dileep , Balasubramaniam Krishnan
Published: January 2022

A method is presented to evaluate the interfacial weakness of aluminium-based honeycomb sandwich structure (HSS) using Shear Horizontal (SH) guided wave. SH guided waves are sensitive to the interfacial properties since the wave particles vibration is oriented parallel to the adhesive-adherent joints. Periodic permanent magnet (PPM) electromagnetic acoustic transducers (EMATs) are used to excite and detect SH-guided waves. A semi-analytical finite element method is developed to simulate the SH wave propagation in HSS. The boundary stiffness approach is used to model the adhesive-adherent interface. The excitation parameters are chosen such that only SH0 mode is generated in the structure. The interaction of the fundamental SH0 wave mode with various defects and the different interface stiffness is analyzed. The frequency-wavenumber analysis is used to study the effect of interface stiffness on SH wave propagation. The analysis reveals that in a perfect bond, SH0 and S0 guided modes are present. The interaction of SH0 mode with the honeycomb core results in the genesis of S0 mode. Thus, the presence or absence of the S0 mode can be used as an indicator of bond quality.

The findings from the FE simulation are validated against the experiment. The analysis shows a reliable non-destructive evaluation of the interface joint and classifying them as good or bad bonds.
Evaluating the Degree of Nonlinearity by Applying the Nonlinear SPC-I Technique in the FEM Simulation of Materials With Breathing Cracks
Authors: Park SeHyuk , Alnuaimi Hamad , Amjad Umar , Kundu Tribikram
Published: January 2022

Detecting internal defects such as fatigue cracks in their early stages is critically important to avoid catastrophic failures. However, detection of micro-scale defects poses a challenge to NDT/SHM (Non-Destructive Testing & Structural Health Monitoring) community. Conventional linear ultrasonic techniques that use absolute time of flight and attenuation to monitor damage progression encounter difficulty in detecting small defects. On the other hand, nonlinear ultrasonic techniques have been proven to be more reliable and sensitive to micro-scale defects. This study uses the nonlinear Sideband Peak Count Index (SPC-I) technique to evaluate the nonlinearity of the material. The problem is simulated using the finite element method (FEM). Fatigue cracks are simulated as breathing cracks. The problem is modeled as an infinite medium to minimize the geometrical effects such as reflections from the boundaries. A narrow band signal is excited and propagated through the material in a single sided excitation/detection setup. The degree of nonlinearity caused by breathing cracks is investigated for multiple configurations. First, the problem is modeled with no cracks to be taken as a reference condition. Then thick crack and thin crack (breathing crack) are modeled, analyzed, and compared. Finally, problems with different number of breathing cracks are simulated and analyzed. All simulated results are compared to investigate the dependence of the degree of nonlinearity on the density and orientation of the cracks.
Linear and Nonlinear Analysis of Additively Manufactured Material With Different Porosity Induced by Varying Material Printing Speed Using Guided Acoustic Waves
Authors: Park SeHyuk , Alnuaimi Hamad , Hayes Anna , Sitkiewicz Madison , Amjad Umar , Muralidharan Krishna , Kundu Tribikram
Published: January 2022

Guided acoustic wave based techniques have been found to be very effective for damage detection, and both quantitative and qualitative characterization of materials. In this research, guided acoustic wave techniques are used for porosity evaluation of additively manufactured materials. A metal 3D printer, Concept Laser Mlab 200 R Cusing™, is used to manufacture 316L additively manufactured (AM) stainless steel specimens. Two levels of porosity are investigated in this study, which was controlled by a suitable combination of scan speed and laser power. The sample with lower level of porosity is obtained with a low scanning speed. Lead Zirconate Titanate (PZT) transducers are used to generate guided acoustic waves. The signal is excited and propagated through the specimens in a single sided transmission mode setup. Signal processing of the recorded signals for damage analysis involves both linear and nonlinear analyses. Linear ultrasonic parameters such as the time-of-flight and magnitude of the propagating waves are recorded. The nonlinear ultrasonic parameter, the Sideband Peak Count Index (SPC-I) is obtained by a newly developed nonlinear analysis technique. Results obtained for both specimens are analyzed and compared using both linear and nonlinear ultrasonic techniques. Finally, the effectiveness of SPC-I technique in monitoring porosity levels in AM specimens is discussed.
Detection of Defects in Titanium Using Shear Horizontal Guided Waves
Authors: Peyton Christian , Edwards Rachel S. , Dixon Steve , Dutton Ben , Vesga Wilson
Published: January 2022

This paper investigates the interaction behaviour between the fundamental shear horizontal guided wave mode and small defects, in order to understand and develop an improved inspection system for titanium samples. In this work, an extensive range of defect sizes have been simulated using finite element software. The SH0 reflection from a defect has been shown previously to depend on its length as the total reflection consists of reflections from both the front and back face. However, for small defect widths, this work has found that the width also affects this interference, changing the length at which the reflection is largest. In addition, the paper looks at how the size of the defect affects the mode converted S0 reflection and SH0 diffraction. The relationship between the SH0 diffraction and defect size is shown to be more complex compared to the reflections. The mode converted S0 reflection occurs at an angle to the incident wave direction; therefore, the most suitable angle for the detection has been found. Simultaneous measurement of multiple waves would bring benefits to inspection.
A Remote Solitary Wave–based Technique for Monitoring Corrosion in Steel Structures: Numerical Analysis and Experimental Validation
Authors: Jalali Hoda , Rizzo Piervincenzo
Published: January 2022

A new corrosion monitoring technique based on the generation and propagation of highly nonlinear solitary waves in 1D granular crystals has been developed recently. In this method, a monoperiodic array of spherical particles, interacting via Hertzian contact forces, is in point contact with the structure or material to be inspected. The array is part of a wireless unit used to induce the wave in the chain and record the solitary waveform remotely. Compared to classical NDE techniques used for thickness monitoring, the developed method is low cost, portable, and simple. This study presents a numerical and an experimental investigation of the sensitivity of solitary waves to localized corrosion. In the experimental study, a corroding steel plate was monitored using solitary waves to examine the effect of corrosion in the plate on the solitary waves interacting with the plate. Furthermore, a discrete element model was coupled with a finite element model to numerically predict the effect of localized corrosion on the delay and the amplitude of the reflected solitary waves formed at the chain-plate interface. The plate was studied in both pristine and corroded conditions. Furthermore, the study investigated customizing the granular chain design to achieve solitary wave-based sensors that can be used in high-temperature environments with maximum sensitivity to corrosion. The numerical results were in good agreement with experimental results and showed that the reflected solitary waves are affected by the presence and the propagation of corrosion in the plate. It was also shown that the sensitivity of the method increases for thinner plates or when the depth of corrosion exceeds half of the plate thickness.
Evaluating Temper Embrittlement in HY-80 Steel Using Magnetic Barkhausen Noise and Microstructural Characterization
Authors: Roberts Michael , D’Ambra Charles , Schibler Jason , Manuel Michele , Krause Thomas W. , Saleem Aroba
Published: January 2022

HY80 steel is a low-carbon steel known for embodying high strength and toughness properties. This steel is used in submarine applications. Temper embrittlement, which is the reduction of fracture toughness, occurs in steels when subject to aging and drastic temperature fluctuations. These changes occur in submarines over time while in underwater environments. During temper embrittlement, impurity atoms and carbides migrate to grain boundaries, which make the steel more susceptible to fracture. A non-destructive testing (NDT) method is desirable to assess the temper embrittlement damage in HY80. Magnetic Barkhausen Noise (MBN) is of interest as being a potential NDT method for analyzing HY80. Focusing on microstructural characterization and its effect on MBN could have implications for establishing an MBN based method to detect varied stages of temper embrittlement in HY80 steel. In this research, samples of HY80 were prepared and heat treated for 16–336 hours to mimic various degrees of temper embrittlement. Microstructural changes with heat treatment were characterized and connected to the MBN produced at each holding time. Methods consisted of performing scanning electron microscopy (SEM) and using an MBN measurement system. It was observed that as holding time increases, grain size increases and carbide density within the grains decreases. These carbides, which act as pinning sites, make it more difficult for domain walls to move, consequently affecting MBN energy.
Edge Illumination X-Ray Phase Contrast Imaging and Ultrasonic Attenuation for Porosity Quantification in Composite Structures
Authors: Shoukroun Dana , Olivo Sandro , Fromme Paul
Published: January 2022

Carbon fiber reinforced composites are widely used in the aerospace industry, due to their low weight and high strength. Porosity often occurs during the manufacturing of composite structures, which can compromise the structural integrity of the part and affect its mechanical properties. In the aerospace industry a typical requirement for structural components is for the porosity content to be kept below 2%. Non-destructive evaluation (NDE) techniques are used to estimate the porosity content in composite components, the most common being ultrasonic attenuation and X-ray computed tomography (CT).

Planar Edge Illumination X-ray Phase Contrast Imaging (EI XPCI) was used to quantify the porosity content in woven carbon fiber reinforced composite plates with porosity ranging between 0.7% and 10.7%. A new metric was introduced, the standard deviation of the differential phase (STDVDP) signal, which represents the variation of inhomogeneity in the plates for features of a scale equal to or above the system resolution (here 12μm). The SDTVDP was found to have a very high correlation with porosity content estimated from matrix digestion and ultrasonic attenuation, hence providing a promising new methodology to quantify porosity in composite plates.
Combined Inductive and Capacitive NDE Technique for Insulator-Conductor Hybrid Structures
Authors: Zhu Ting , Wen Kaijie , Deng Chengjie , Yin Xiaokang , Zhang Xiaorui , Yuan Xinan , Li Wei , Chen Guoming
Published: January 2022

This paper presents a new inductance-capacitance non-destructive detection technique with a form of planar dual-mode sensor. The detection principle of the sensor in mode-L and mode-C was analyzed, and the feasibility of this new combination of inductance and capacitance nondestructive detection technique was demonstrated. A PCB sensor was designed and manufactured, a further research on the characteristic physical field of the designed sensor using finite element simulation software was presented. A suitable detection system was developed to realize this new dual-mode detection technique using this dual-mode detection sensor. Typical test pieces were prepared and tested. The detection results show that the proposed new inductance-capacitance technique can detect typical defects in both insulator and conductor layers of the insulator-conductor hybrid structure with a good balance of inductance and capacitance performance, indicating that this new detection technique can be further used for insulator-conductor hybrid structures non-destructive testing with the potential for structure detection, quantitative evaluation, damage imaging and other applications.
Aboveground Storage Tanks Leak Detection Through Acoustic Emission Sensor Nodes
Authors: Bogomolov Denis , Testoni Nicola , de Marchi Luca , Borzone Tommaso , Terribile Antonio , Giunta Giuseppe , Marzani Alessandro
Published: January 2022

In oil depots and fuel storage facilities, undetected storage tanks damages can lead to the leakage of the oil stored in the soil leading to pollution and economical losses. Leaks are generally due to the perforation of the storage tank floor due to corrosion. The detection of corrosion and leaks is a complicated task, especially for operative tanks with inaccessible floor for detailed inspections and is generally attempted by mean of acoustic emission systems operating from the outer skin of the tank. In this paper, we present a compact sensor node (SN) designed for long-term and real-time acoustic emission monitoring. The SN exploits up to three inexpensive low-frequency sensors based on piezoelectric diaphragms, and it is capable by means of built-in Digital Signal Processing functionalities to process the acquired time waveforms extracting the AE features usually required by testing protocols. An experimental validation on a floating-roof aboveground storage tank 17 m high and 18 m in diameter, filled with water to a level of about 6.2 m, is proposed. Leaks were induced by opening and closing a drainage valve existing at the bottom skirt of the storage tank while acoustic emission signals were recorded at three sensors and processed in real time. Designed nozzles of different diameter, from 1 mm to 9 mm, where used to simulate leakages of different entities.

The results confirm the possibility of detecting and monitoring leaks of various diameters in the low-frequency region 1–2 kHz not traditionally considered by state-of-art acoustic-emission monitoring systems.
Studies on Novel Hyperlens Concept for Ultrasonic Non Destructive Evaluation
Authors: Kumar Pradeep , Syed Akbar Ali Mohamed Subair , Rajagopal Prabhu
Published: January 2022

Ultrasonic imaging is widely preferred in the field of non-destructive evaluation, medical diagnostics, and underwater inspection because it offers various advantages such as safety and versatility. However, conventional ultrasonic imaging methods suffer from the poor resolution limit imposed by the loss of information on fine features within the near-field. Metamaterial concepts have attracted much research interest in recent years, yielding extraordinary benefits such as super-resolution imaging, vibration damping, and cloaking. In the context of imaging, Metalenses allow the successful transfer of the information carried by the evanescent waves to far-field by amplifying them and hence help in overcoming the resolution limit. Hyperlenses enable subwavelength resolution along with spatial magnification by transforming evanescent waves scattered past a material artifact into propagating waves at the far-field ‘imaging’ end of the medium. This paper discusses novel radially symmetric ultrasonic hyperlens for imaging defects in the context of non-destructive evaluation, a topic that has not been studied much. The effect of parameters such as defect extent and distance between the lens on the subwavelength imaging of the hyperlens is studied using numerical simulations. This study investigates the magnification achievable using the proposed hyperlens and the effectiveness of this approach for nondestructive evaluation using cost-effective ‘everyday’ transducers.
Biological Mechanisms Underlying the Aging Process: The Ideas and Techniques of Genetics Are Being Used to Obtain New Insight into the Problems of Aging
Authors: Curtis Howard J.
Published: January 2022

In this article the several theories put forward to explain the biological mechanisms underlying the aging process are examined. The only ones which attack the problem from the point of view of basic biological mechanisms are the wear-and-tear theory and the somatic mutation theory. The finding that radiation accelerates the aging process is a potent tool for attacking the problem experimentally. Experiments with mice specifically designed to verify the wear-and-tear theory showed conclusively that stress per se does not contribute to aging, and no experimental evidence could be found to support the theory.

On the other hand, a great deal of evidence now available indicates that mutations in somatic cells play a dominant role in aging. It is further shown that the organs having cells which frequently undergo cell division take part in the aging process very little, if at all. Organs having cells which seldom, if ever, divide have no opportunity to throw off either spontaneous or induced mutations, and it is these organs which are responsible for the aging of the animal. Spontaneous mutations build up at a rapid rate in these organs. A cell may continue to function normally long after it has suffered a deleterious mutation, and this accounts for much of the delay in the expression of radiation damage. It is suggested that the mutation rates for somatic cells are very much higher than the rates for gametic cells, and that this circumstance insures the death of the individual and the survival of the species.

Reproduced with permission from
Science
. Copyright 1963 American Association for the Advancement of Science.
Review Lectures on Senescence: I. The Causes of Aging
Authors: Smith J. Maynard
Published: January 2022

Aging processes are defined as those that increase the susceptibility of individuals as they grow older to the factors that may cause death. Various possible theories of aging are considered, and evidence that may help to decide between them is discussed. Changes in different organ systems may be merely symptoms of some single aging process, or they may be largely independent and synchronized by natural selection. Even if different organ systems age independently, they may do so as a result of similar changes at a cellular level. Cellular theories of aging may have to take into account the effects of selection between the cells in a tissue.

The effects of radiation and somatic mutation theories of aging are discussed. It is suggested that radiation shortens life by inducing somatic mutations but that normal aging is not to any important extent caused by somatic mutations, although it may result from changes in cells that have effects on the physiology of the individual similar to those of somatic mutations. Evidence is presented that in
Drosophila
and in mice there are two phases in the life-span. In
Drosophila
, there is an initial “aging” phase, which is irreversible and occurs at a rate approximately independent of temperature, and a second “dying” phase, which is temperature-dependent in rate and reversible at lower temperatures.

Reproduced by permission.

J. Maynard Smith, Review Lectures on Senescence: I. The Causes of Aging.
Proc. R. Soc. London Ser. B
157
, 115-127 (1962).
Evolution of Human Longevity and the Genetic Complexity Governing Aging Rate
Authors: Cutler Richard G.
Published: January 2022

The genetic complexity of processes governing the aging rate of humans was estimated by determining the maximum rate at which life-span has evolved along the hominid ancestral-descendant sequence. Maximum life-span potential was found to have increased approximately twofold over the past 3 million years, reaching a maximum rate of increase of 14 years per 100,000 years about 100,000 years ago. It is estimated that about 0.6% of the total functional genes have received substitutions leading to one or more adaptive amino acid changes during this 100,000-year time-period. This suggests that aging is not the result of the expression of a large number of independently acting processes. Instead, primary aging processes appear to exist in which only a few genetic changes are necessary to uniformly decrease the aging rate of many different physiological functions.

Reproduced by permission.

Richard G. Cutler, Evolution of Human Longevity and the Genetic Complexity Governing Aging Rate.
Proc. Natl. Acad. Sci. U.S.A.
72
, 4664-4668 (1975).
Action of food restriction in delaying the aging process
Authors: Masoro E. J. , Yu B. P. , Bertrand H. A.
Published: January 2022

Food restriction has long been known to prolong life in rodents, and recent studies have shown it to have antiaging effects in regard to a variety of physiologic and pathologic processes. It has been suggested that these actions of food restriction relate to the reduction of metabolic rate per unit of body mass brought about by this dietary regimen. Data are presented in this report showing that food restriction can have a marked life-prolonging action in rats without reducing caloric intake per gram of body weight. Moreover, the food-restricted rats consumed a greater number of calories per gram of body weight during their lifetimes than did the rats fed ad lib, yet they lived longer. Thus, the data in this report do not support the concept that food restriction slows the rate of aging by decreasing the metabolic rate.

E. J. Masoro, B. P. Yu, H. A. Bertrand, Action of food restriction in delaying the aging process.
Proc. Natl. Acad. Sci. U.S.A.
79
, 4239-4241 (1982).