bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of amino acid‐based formula added to four‐food elimination in adult eosinophilic esophagitis patients: A randomized clinical trial
Authors: de Rooij Willemijn E. , Vlieg – Boerstra Berber , Warners Marijn J. , Van Ampting Marleen T.J. , van Esch Betty C. A. M. , Eussen Simone R. B. M. , Bredenoord Albert J.
Published: November 2021

Background

Elimination of key foods restricts dietary options in eosinophilic esophagitis (EoE) patients. Addition of amino acid‐based formula (AAF) to an elimination diet might facilitate adherence and, therefore, enhance efficacy of dietary management.

Aim

To evaluate whether addition of AAF to a four‐food elimination diet (FFED) is more effective than FFED alone in decreasing eosinophilia, endoscopic signs, and clinical outcomes.

Methods

This randomized controlled trial enrolled 41 adult patients with active EoE (≥15 eosinophils (eos) per high power field (hpf)) at baseline biopsy. Subjects were randomized (1:1 ratio) to groups given a FFED or FFED with addition of AAF providing 30% of their daily energy needs (FFED + AAF). Histological disease activity, endoscopic signs, symptoms, and disease‐related quality of life (EoEQoL) were measured at baseline and after 6 weeks of intervention.

Results

Patients (60% male, age 34.5 (interquartile range (IQR) 29–42.8 years)) were randomized to FFED (n = 20) or FFED + AAF (n = 21); 40 participants completed the diet. Complete histological remission (<15 eos/hpf) was achieved in 48% of FFED + AAF subjects (n = 21) vs. 25% of FFED subjects (n = 20), respectively (p = 0.204). Peak eosinophil counts (PEC) decreased significantly in both groups between baseline and week 6, but the change in PEC between groups was not different (p = 0.130). A significant but similar endoscopic and symptomatic reduction was observed in both groups (all; p<0.05). Total EoEQoL scores significantly improved in the FFED + AAF group between baseline and week 6 (p = 0.007), and not in the FFED group.

Conclusion

The addition of AAF to a FFED did not lead to a larger decrease in PEC between baseline and 6 weeks, but may result in a significant improvement of QoL in adult EoE patients NL6014 (NTR6778).
Role of the Lumbosacral Transition Vertebra and Vertebral Lamina in the Pathogenesis of Lumbar Disc Herniation
Authors: Jin Lin , Yin Yingchao , Chen Wei , Zhang Ruipeng , Guo Jialiang , Tao Shiwu , Guo Zheming , Hou Zhiyong , Zhang Yingze
Published: November 2021

Objective

To investigate the prevalence of lumbosacral transition vertebrae (LSTVs) in both the normal population and the lumbar disc herniation (LDH) population and to determine the risk factors for LDH.

Methods

Between January 2019 and September 2020, all patients aged 18–39 years and underwent an anteroposterior (AP) X‐ray of the lumbar vertebrae were retrospective reviewed in our institution. Those patients who were diagnosed with LDH were eligible for inclusion in the LDH group. During the same period, those patients admitted to our hospital who underwent an anteroposterior X‐ray of the lumbar spine and had not been diagnosed with LDH were included in the control group. Those patients with disease that might affect the lumbar anatomy were excluded from both groups. The type of LSTV was classified according to the Castellvi classification. The height of the lumbar vertebral lamina was evaluated through the h/H index. The inter‐ and intra‐observer reliability was evaluated by one senior radiologist and one senior orthopedist using intraclass correlation coefficient (ICC). The association between the LSTV and the herniation level was also investigated. Binary logistic regression was used to explore the association of different factors between the LDH group and the control group.

Results

Two hundred LDH patients (115 male and 85 female) and 200 individuals (108 male and 92 female) were investigated retrospectively. The prevalence of LSTVs was 71.5% (n = 143) in the LDH group and 34.0% (n = 68) in the control group. The most frequent LSTV types were type Ib and type IIa. The inter‐ and intra‐observer ICCs of the measurement of “h/H” index and the classification of LSTV were all “excellent” (ICC > 0.90). The median h/H index in the control group was significantly higher than that in the LDH group (0.28 (0.26, 0.31) vs 0.34 (0.31, 0.37), P = 0.000). The distribution of the Castellvi classification in the L4/5 and L5/S1 herniation patients was significantly different (P = 0.048). LSTVs, BMI and the h/H index were closely associated with LDH, with odds ratios of 3.06 (95% CI: 2.12–4.43), 1.23 (95% CI: 1.13–1.33) and 0.09 (95% CI: 0.05–0.15), respectively. The incidence of L4/5 disc herniation in patients with an LSTV was significantly more common than that in patients with L5/S1 disc herniation (P = 0.048).

Conclusion

The prevalence of LSTVs was 34.0% in the control group and 71.5% in the LDH group; LSTVs and BMI were positively correlated with LDH, and h/H was negatively correlated with LDH.
Past and Present Intergroup Contact and Conflict Among Inhabitants of Former Mixed Villages of Cyprus: The Role of Individual and Collective Experiences in Predicting Attitudes and Trust
Authors: Kende Judit , Psaltis Charis , Reiter Julia , Fousiani Kyriaki , Cakal Huseyin , G. T. Green Eva
Published: November 2021

Positive attitudes and trust towards former adversaries facilitate reconciliation and peace building. Both historical and current intergroup experiences such as intergroup contact and conflict predict intergroup attitudes and trust, but no previous research has investigated the joint effects of these experiences. Therefore, we study the interplay of positive intergroup contact preceding conflict, negative experiences of the conflict, and positive intergroup contact following conflict. Drawing on social representations theory and using a multilevel design, we highlight the importance of both individual and collective experiences. We examine the effects of such experiences on intergroup attitudes and trust among a large sample of Greek Cypriots (N = 802) and Turkish Cypriots (N = 718) from 54 formerly ethnically mixed villages in the context of a protracted and frozen conflict in Cyprus. Present‐day individual contact related to more positive attitudes and higher trust regardless of participants’ past experiences of conflict or contact. Furthermore, past collective contact experiences predict more positive attitudes and higher trust, whereas past collective conflict experiences predicted more negative attitudes and lower trust. Finally, present‐day contact closes the gap in trust between respondents with low and high past contact. Overall, both current and historical and individual and collective experiences matter.
Molecular phylogeny of fucoxanthin‐chlorophyll a/c proteins from Chaetoceros gracilis and Lhcq/Lhcf diversity
Authors: Kumazawa Minoru , Nishide Hiroyo , Nagao Ryo , Inoue‐Kashino Natsuko , Shen Jian‐Ren , Nakano Takeshi , Uchiyama Ikuo , Kashino Yasuhiro , Ifuku Kentaro
Published: November 2021

Diatoms adapt to various aquatic light environments and play major roles in the global carbon cycle using their unique light‐harvesting system, i.e. fucoxanthin chlorophyll a/c binding proteins (FCPs). Structural analyses of photosystem II (PSII)–FCPII and photosystem I (PSI)–FCPI complexes from the diatom Chaetoceros gracilis have revealed the localization and interactions of many FCPs; however, the entire set of FCPs has not been characterized. Here, we identify 46 FCPs in the newly assembled genome and transcriptome of C. gracilis. Phylogenetic analyses suggest that these FCPs can be classified into five subfamilies: Lhcr, Lhcf, Lhcx, Lhcz, and the novel Lhcq, in addition to a distinct type of Lhcr, CgLhcr9. The FCPs in Lhcr, including CgLhcr9 and some Lhcqs, have orthologous proteins in other diatoms, particularly those found in the PSI–FCPI structure. By contrast, the Lhcf subfamily, some of which were found in the PSII–FCPII complex, seems to be diversified in each diatom species, and the number of Lhcqs differs among species, indicating that their diversification may contribute to species‐specific adaptations to light. Further phylogenetic analyses of FCPs/light‐harvesting complex (LHC) proteins using genome data and assembled transcriptomes of other diatoms and microalgae in public databases suggest that our proposed classification of FCPs is common among various red‐lineage algae derived from secondary endosymbiosis of red algae, including Haptophyta. These results provide insights into the loss and gain of FCP/LHC subfamilies during the evolutionary history of the red algal lineage.
EBUS versus EUS‐B for diagnosing sarcoidosis: The International Sarcoidosis Assessment (ISA) randomized clinical trial
Authors: Crombag Laurence M. M. , Mooij‐Kalverda Kirsten , Szlubowski Artur , Gnass Maciej , Tournoy Kurt G. , Sun Jiayuan , Oki Masahide , Ninaber Maarten K. , Steinfort Daniel P. , Jennings Barton R. , Liberman Moishe , Bilaceroglu Semra , Bonta Peter I. , Korevaar Daniël A. , Trisolini Rocco , Annema Jouke T.
Published: November 2021

Background and objective

Endosonography with intrathoracic nodal sampling is proposed as the single test with the highest granuloma detection rate in suspected sarcoidosis stage I/II. However, most studies have been performed in limited geographical regions. Studies suggest that oesophageal endosonographic nodal sampling has higher diagnostic yield than endobronchial endosonographic nodal sampling, but a head‐to‐head comparison of both routes has never been performed.

Methods

Global (14 hospitals, nine countries, four continents) randomized clinical trial was conducted in consecutive patients with suspected sarcoidosis stage I/II presenting between May 2015 and August 2017. Using an endobronchial ultrasound (EBUS) scope, patients were randomized to EBUS or endoscopic ultrasound (EUS)‐B‐guided nodal sampling, and to 22‐ or 25‐G ProCore needle aspiration (2 × 2 factorial design). Granuloma detection rate was the primary study endpoint. Final diagnosis was based on cytology/pathology outcomes and clinical/radiological follow‐up at 6 months.

Results

A total of 358 patients were randomized: 185 patients to EBUS‐transbronchial needle aspiration (EBUS‐TBNA) and 173 to EUS‐B‐fine‐needle aspiration (FNA). Final diagnosis was sarcoidosis in 306 patients (86%). Granuloma detection rate was 70% (130/185; 95% CI, 63–76) for EBUS‐TBNA and 68% (118/173; 95% CI, 61–75) for EUS‐B‐FNA (p = 0.67). Sensitivity for diagnosing sarcoidosis was 78% (129/165; 95% CI, 71–84) for EBUS‐TBNA and 82% (115/141; 95% CI, 74–87) for EUS‐B‐FNA (p = 0.46). There was no significant difference between the two needle types in granuloma detection rate or sensitivity.

Conclusion

Granuloma detection rate of mediastinal/hilar nodes by endosonography in patients with suspected sarcoidosis stage I/II is high and similar for EBUS and EUS‐B. These findings imply that both diagnostic tests can be safely and universally used in suspected sarcoidosis patients.
Comparative Risk: Dread and Unknown Characteristics of the COVID‐19 Pandemic Versus COVID‐19 Vaccines
Authors: Wong Jody Chin Sing , Yang Janet Zheng
Published: November 2021

This research characterizes risk perceptions of the COVID‐19 pandemic and the COVID‐19 vaccines based on the dread and unknown dimensions of the psychometric paradigm. We examine if mental risk comparisons of these two risk objects influence risk mitigation behaviors (vaccination intention; vaccine acceptance; preventive behaviors) and emotional responses among unvaccinated and vaccinated Americans. A survey (N = 1532) was conducted based on a nationally representative sample of U.S. adults in May 2021. Results reveal considerable impact of risk comparison, especially along the dread dimension, on the outcomes of interest. In essence, this research reveals critical insights regarding vaccine hesitancy and risk communication about vaccination.
Judging Pharmaceutical Environmental Risk by its Cover? The Effects of Prescription Medication and Disease Severity on Environmental Risk Perception
Authors: Luís Sílvia , Moura Rita , Lima Maria Luísa , Poggio Lucia , Aragonés Juan Ignacio , Camilo Cristina
Published: November 2021

Recent wastewater analyses performed in care homes for the elderly showed high levels of water pollution resulting from pharmaceutical waste. The way people perceive the environmental risk of pharmaceuticals can contribute to reversing this problem, but the factors that influence risk perception remain relatively unknown. The aims of the study are two‐fold. We first focused on exploring the levels of knowledge regarding environment/water pollution due to pharmaceutical residues from the groups responsible for prescribing (health professionals), handling (staff), and consuming pharmaceuticals (residents) in care homes for the elderly. Second, we assessed the environmental risk perception of pharmaceuticals based on two main factors: prescription medication (nonprescribed versus prescribed) and disease severity (milder versus severe disease), accounting for their level of knowledge (deficit versus sufficiency of knowledge). The study was designed based on correlational research. Data were collected in homes for the elderly located in three Southwestern European countries (N = 300), using self‐report surveys. Current knowledge was perceived to be low and the need to know more was perceived to be high, across all groups. As hypothesized, results indicated that to assess the environmental risk, participants made use of information that was unrelated to pharmaceutical persistence, bioaccumulation, and toxicity (PBT). Prescribed pharmaceuticals and/or medication used to treat severe diseases were perceived as being more hazardous for the environment. Simple main effects analysis comparing between knowledge levels confirmed that this effect occurred mostly when participants had knowledge deficit for disease severity but not for prescription medication. These misconceptions might discourage taking an active role in reducing the impact of pharmaceutical residues in the environment.
Throwing performance by playing positions of male handball players during the European Championship 2020
Authors: Pueo Basilio , Tortosa‐Martínez Juan , Chirosa‐Rios Luis J. , Manchado Carmen
Published: November 2021

The aim of this study was to analyze the throwing velocity and effectiveness of elite male handball players during the European Championship 2020. A local positioning system was used for the first time in a European Championship to collect 6568 throw events from 337 players of 24 national teams during 65 matches. ANOVA (F = 80.8, p < 0.01, η2 = 0.058) revealed that back players throws were significantly faster (24.3–26.5 m/s) than the rest of the players (22.2–22.5 m/s). Similarly, throws made from the central zone showed the highest speed values of 28.0 m/s (F = 43.2, p < 0.01, η2 = 0.050). In regard to the goal hit zone, higher speeds were shown for throws in side zones (24.9–26.8 m/s) compared to central zones (23.0–23.8 m/s) (F = 49.0, p < 0.01, η2 = 0.063). Effectiveness was higher in wing players (62%–64%) than the rest (45%–56%) (F = 30.9, p < 0.01, η2 = 0.023). Interestingly, the two higher velocity categories (>22 m/s) showed similar effectiveness (~60%), which were higher than the preceding slower category of 17–22 m/s (39.7%) (F = 175.1, p < 0.01, η2 = 0.074). Regarding court zones, throws from first‐line zones (48%–60%), were more effective than from second line (38%–43%) (F = 13.1, p < 0.01, η2 = 0.016). With respect to the goal hit zone, effectiveness was higher in side (72%–77%) than in central zones (58%–64%) (F = 523.2, p < 0.01, η2 = 0.418). Coaches should improve the throwing velocity of players but also train at submaximal velocities (effective velocity) to save energy and reduce the potential risk of injury. Finally, training should be specialized according to the performance shown by players from different throwing zones, rather than from playing positions.
Effects of 16 weeks of pyramidal and polarized training intensity distributions in well‐trained endurance runners
Authors: Filipas Luca , Bonato Matteo , Gallo Gabriele , Codella Roberto
Published: November 2021

The aim of this study was to investigate the effects of four different training periodizations, based on two different training intensity distributions during a 16‐week training block in well‐trained endurance runners. Sixty well‐trained male runners were divided into four groups. Each runner completed one of the following 16‐week training interventions: a pyramidal periodization (PYR); a polarized periodization (POL); a pyramidal periodization followed by a polarized periodization (PYR → POL); and a polarized periodization followed by a pyramidal periodization (POL → PYR). The PYR and POL groups trained with a pyramidal or polarized distribution for 16 weeks. To allow for the change in periodization for the PYR → POL and POL → PYR groups, the 16‐week intervention was split into two 8‐week phases, starting with pyramidal or polarized distribution and then switching to the other. The periodization patterns were isolated manipulations of training intensity distribution, while training load was kept constant. Participants were tested pre‐, mid‐ and post‐intervention for body mass, velocity at 2 and 4 mmol·L−1 of blood lactate concentration (vBLa2, vBLa4), absolute and relative peak oxygen consumption () and 5‐km running time trial performance. There were significant group × time interactions for relative (p < 0.0001), vBLa2 (p < 0.0001) and vBLa4 (p < 0.0001) and 5‐km running time trial performance (p = 0.0001). Specifically, participants in the PYR → POL group showed the largest improvement in all these variables (~3.0% for relative , ~1.7% for vBLa2, ~1.5% for vBLa4, ~1.5% for 5‐km running time trial performance). No significant interactions were observed for body mass, absolute , peak heart rate, lactate peak and rating of perceived exertion. Each intervention effectively improved endurance surrogates and performance in well‐trained endurance runners. However, the change from pyramidal to polarized distribution maximized performance improvements, with relative representing the only physiological correlate.
SARS Cov‐2 vaccination induces de novo donor‐specific HLA antibodies in a renal transplant patient on waiting list: A case report
Authors: Abu‐Khader Ahmad , Wang Wenjie , Berka Meriam , Galaszkiewicz Iwona , Khan Faisal , Berka Noureddine
Published: November 2021

The ability of COVID‐19 vaccination to induce anti‐HLA antibodies (Abs) formation in renal transplant candidates is not well studied. A 42‐year‐old man on a renal transplant waitlist, with no sensitization history, was tested for DSA before and after COVID‐19 vaccination. Patient has consistently tested negative for COVID‐19 virus. Eighteen days after receiving first dose of mRNA‐based vaccine, flow cytometry crossmatch (FCXM) was strongly positive with de novo donor‐specific Ab (dnDSA) against B57 and de novo non‐DSA against B58. Before vaccination, preliminary FCXM was negative with no anti‐HLA Abs. This event prompted the transplant team to cancel the surgery. COVID‐19 vaccination could be associated with anti‐HLA Abs formation in renal patients on waitlists that could affect future transplantability.
GIScience and neighborhood change: Toward an understanding of processes of change
Authors: Delmelle Elizabeth C.
Published: November 2021

Processes of neighborhood change are the result of the unfolding of events and decisions by multiple actors operating at varying spatial and temporal scales, enabled and constrained upon an unequal urban landscape. The contributions of GIScience toward understanding these processes have evolved from the simple mapping of static, cross‐sectional maps toward an embrace of novel data and methods that enable longitudinal trajectories to be extracted and neighborhood futures to be predicted. In this article, I review these advancements and chart a course forward that considers a future research agenda that is critically cognizant of the potentials and perils of new data sources and method, is representative of the full spectrum of processes operating both visibly and invisibly that give rise to observed neighborhood outcomes, and considers their varying spatial and temporal scales.
Surgical removal of intra‐articular loose bodies from the cervical articular process joints in 5 horses
Authors: Tucker Rachel , Parker Russell A. , Meredith Lauren E. , Hughes Thomas K. , Foote Alastair K.
Published: November 2021

Objective

To describe the surgical removal of intra‐articular loose bodies (LBs) from the cervical articular process joints (APJs) in five horses and to describe the outcome of the surgery.

Study design

Short case series.

Animals

Five client‐owned horses with naturally occurring LBs within the cervical APJs.

Methods

Medical records were reviewed of horses that were diagnosed with LBs of the cervical APJs on computed tomography (CT), where the LBs were subsequently removed surgically. Details of case selection and surgical technique were reviewed along with postoperative complications and clinical outcome. Histopathology was performed on LBs in some cases.

Results

Surgery was performed on six APJs in five horses. Of the 14 LBs identified with CT, 13 were successfully removed from the C4/C5, C5/C6 and C6/C7 articulations. No surgical complications were encountered, and clinical signs of cervical dysfunction improved in all horses. All clinical cases returned to ridden work by 6 months post surgery. Histopathologic examination revealed the removed structures to be osteochondral or chondral loose bodies consisting of cartilaginous proliferation with or without ossification and central necrosis.

Conclusions

Surgical removal of LBs is achievable from the cervical APJs and can result in the resolution of cervical pain. This procedure offers a new treatment option for management of selected horses with cervical pain, following thorough assessment and CT imaging.
A Surrogate Model to Predict Production Performance in Digital Twin-Based Smart Manufacturing
Authors: Chua Ping Chong , Moon Seung Ki , Ng Yen Ting , Ng Huey Yuen
Published: November 2021

With the dynamic arrival of production orders and unforeseen changes in shop-floor conditions within a production system, production scheduling presents a challenge for manufacturing firms to ensure production demands are met with high productivity and low operating cost. Before a production schedule is generated to process the incoming production orders, production planning is performed. Given the large number of input parameters involved in the production planning, it poses the challenge on how to systematically and accurately predict and evaluate production performance. Hence, it is important to understand the interactions of the input parameters between the production planning and the scheduling. This is to ensure that the production planning and the scheduling are coordinated and can be performed to achieve optimal production performance such as minimizing cost effectively and efficiently. Digital twin presents an opportunity to mirror the real-time production status and analyze the input parameters affecting the production performance in smart manufacturing. In this paper, we propose an approach to develop a surrogate model to predict the production performance using input parameters from a production plan using the capabilities of real-time synchronization of production data in digital twin. Multivariate adaptive regression spline (MARS) is applied to construct a surrogate model based on three categories of input parameters, i.e., current production system load, machine-based and product-based parameters. An industrial case study involving a wafer fabrication production is used to develop the surrogate model based on a random sampling of varying numbers of training data set. The proposed MARS model shows a high correlation coefficient and a large reduction in the number of input parameters for both linear and nonlinear cases with relation to three performances, namely flowtime, tardiness, and machine utilization.
Theoretical Analysis on Nonlinear Buckling, Post-Buckling of Slender Beams and Bi-Stable Mechanisms
Authors: Wu Ke , Zheng Gang
Published: November 2021

Compliant mechanisms (CMs) are used to transfer motion, force, and energy, taking advantages of the elastic deformation of the involved compliant members. A branch of special type of elastic phenomenon called (post) buckling has been widely considered in CMs: avoiding buckling for better payload-bearing capacity and utilizing post-buckling to produce multi-stable states. This paper digs into the essence of beam’s buckling and post-buckling behaviors where we start from the famous Euler–Bernoulli beam theory and then extend the mentioned linear theory into geometrically nonlinear one to handle multi-mode buckling problems via introducing the concept of bifurcation theory. Five representative beam buckling cases are studied in this paper, followed by detailed theoretical investigations of their post-buckling behaviors where the multi-state property has been proved. We finally propose a novel type of bi-stable mechanisms termed as pre-buckled bi-stable mechanisms (PBMs) that integrate the features of both rigid and compliant mechanisms. The theoretical insights of PBMs are presented in detail. To the best of our knowledge, this paper is the first study on the theoretical derivation of the kinematic models of PBMs, which could be an important contribution to this field.
Reliability-Based Analysis and Optimization of the Gravity Balancing Performance of Spring-Articulated Serial Robots With Uncertainties
Authors: Nguyen Vu Linh , Kuo Chin-Hsing , Lin Po Ting
Published: November 2021

This article proposes a method for analyzing the gravity balancing reliability of spring-articulated serial robots with uncertainties. Gravity balancing reliability is defined as the probability that the torque reduction ratio (the ratio of the balanced torque to the unbalanced torque) is less than a specified threshold. In this paper, the reliability analysis is performed by exploiting a Monte Carlo simulation (MCS) with consideration of the uncertainties in the link dimensions, masses, and compliance parameters. A reliability-based design optimization (RBDO) method is also developed to seek reliable spring setting parameters for maximized balancing performance under a prescribed uncertainty level. The RBDO is formulated with consideration of a probabilistic reliability constraint and solved by using a particle swarm optimization (PSO) algorithm. A numerical example is provided to illustrate the gravity balancing performance and reliability of a robot with uncertainties. A sensitivity analysis of the balancing design is also performed. Lastly, the effectiveness of the RBDO method is demonstrated through a case study in which the balancing performance and reliability of a robot with uncertainties are improved with the proposed method.
Fundamental Investigation of Effects of Surrounding Conditions on Measurement Uncertainty in Temperature of Surface-Mounted Components by Thermocouples
Authors: Fukue Takashi , Hirasawa Koichi
Published: November 2021

This study describes the development of an evaluation method of uncertainty in temperature measurement of surface-mounted components by several types of thermocouples. When thermocouples conduct the temperature measurement of the surface-mounted components, the components’ temperature decreases because the thermocouples dissipate heat like a pin fin. Temperature measurement techniques for miniaturized electrical components are strongly needed to ensure the operation’s guaranteed temperature. In this report, a heat transfer experiment around thermocouples installed on the surface of the PCBs was conducted while changing the type and the mounting angle of thermocouples. Through the temperature measurement, the decrease of the temperature around the thermocouples was confirmed.
Cold Gas Spray of Copper on Aluminum Nitride as Substrate for Power Electronics
Authors: Guerrero Margie , Quintero Pedro , Ozdemir Ozan , Schwartz Tricia
Published: November 2021

Ceramic substrates for electronic packaging of high-power applications are growing in demand due to their robustness as power and thermal requirements increase. Aluminum nitride (AlN) has excellent thermal and electrical properties with copper currently being bonded to AlN via a direct bond copper (DBC) technique. However, substrates fabricated by DBC are subjected to thermo-mechanical fatigue during fabrication processes and power cycling. DBC substrate’s reliability is negatively affected by the large mismatch in coefficient of thermal expansion that hinders the possibility of thicker substrates, therefore limiting its use for applications above 20 kV. This work employed cold gas spraying (CGS) to mechanically bond Cu on AlN. CGS is a low-temperature additive manufacturing method that accelerates powder particles at near-supersonic velocities to impact a surface causing plastic deformation and mechanical bonding. On ceramic-metal systems CGS has not been widely studied owing to ceramics’ inability to deform plastically, therefore, surface functionalization was performed to enhance the mechanical interlocking mechanism. A factorial design of experiments (DOE) was used to assess the effect of factors: temperature, pressure, stand-off distance, angle of deposition, and travel speed on various substrate surfaces in the CGS fabrication process. These experiments resulted in a successful deposition of copper on AlN.
Reliability of Electronic Drivers: An Industrial Approach
Authors: Watté P. , van Hees G. , Engelen R. , van Driel W. D.
Published: November 2021

Reliability of electronic drivers, or systems, is crucial for the business of Signify. We manufacture and sell more than a million drivers per year. Field returns taught us what failure modes are important, but this is not sufficient to provide lifetime claims for our products. Being in this business for almost a century, in order to provide detailed lifetime claims, we have established an internal reliability tool. This tool provides our designers the correct information for flawless driver development. The specially developed Electronics Reliability Tool (ERT) uses on the one hand FIT tables provided by handbooks like e.g., Telcordia and on the other hand also considers wear-out mechanisms due to e.g., lightning strikes. Validation and verification of our predictions is performed by collecting sold quantities, field returns, do extensive failure analysis and compare these values with calculated ones. Each internally designed driver is subjected to an ERT calculation. The forecasted lifetime is used as a yard stick to witness the drivers’ targeted lifetime. In our presentation we will demonstrate the tool. In this paper, we describe details of how ERT calculates failure rates. We will also present the comparison between field performance and calculated values of our electronic drivers.
Thermal and Electrical Co-Optimization of a Multi-Chip Double-Sided Cooled GaN Module
Authors: Carlton Hayden , Hossain Md Maksudul , Ur Rashid Arman , Chen Yuxiang , Mantooth Alan , Imran Asif , Luo Fang , Harris John , Krone Alexis , Huitink David
Published: November 2021

The need for high power density electrical converters/inverters dominates the power electronics realm, and wide bandgap semiconducting materials, such as gallium nitride (GaN), provide the enhanced material properties necessary to drive at higher switching speeds than traditional silicon. However, lateral GaN devices introduce packaging difficulties, especially when attempting a double-sided cooled solution. Herein, we describe optimization efforts for a 650V/30A, GaN half-bridge power module with an integrated gate driver and double-sided cooling capability. Two direct bonded copper (DBC) substrates provided the primary means of heat removal from the module. In addition to the novel topology, the team performed electrical/thermal co-design to increase the multi-functionality of module. Since a central PCB comprised the main power loop, the size and geometry of the vias and copper traces was analyzed to determine optimal functionality in terms of parasitic inductance and thermal spreading. Thermally, thicker copper layers and additional vias introduced into the PCB also helped reduce hot spots within the module. Upon fabrication of the module, it underwent electrical characterization to determine switching performance, as well as thermal characterization to experimentally measure the total module’s thermal resistance. The team successfully operated the module at 400 V, 30 A with a power loop parasitic inductance of 0.89 nH; experimental thermal measurements also indicated the module thermal resistance to be 0.43 C/W. The overall utility of the design improved commensurately by introducing simple, yet effective electrical/thermal co-design strategies, which can be applied to future power modules.
BER Illusion Methodology: A Novel, Open Sourced and Scalable Approach to Troubleshooting High Radix Photonics Interconnects in a Modern Hyperscale Datacenter
Authors: Rao Shreyas , Chakravarty Abhijit , Jani Dharmesh
Published: November 2021

Facebook Datacenter consists of a large number of servers that run diverse Facebook services aggregated to serve any given user request. To allow this aggregation, servers have to interact with each other via different traffic flows which are managed by networking fabric. The underlying connection powering this fabric consists of a large number of pluggable optical interconnects and On Board Optical (OBO) modules carrying production data. This connectivity at scale requires fast and reliable detection of the link failures to ensure resolution. In the first generation of the deployments, detection of the link failure was sequential and a slow process. The troubleshoot process was equally tedious as the available tools required characterizing one optical transceiver at a time. Further, the failure analysis also presented a majority of resolution with no failed optics as a root cause resulting in high No Trouble Found (NTF) rate.

In this paper we introduce a novel link failure detection and resolution method that improves on the previous method across three dimensions: faster resolution, reliable troubleshooting and scalable implementation. We introduce BER Illusion Methodology (BIM) that is a highly scalable and resource efficient solution that significantly reduces the time taken to troubleshoot pluggable optical interconnects. This is also scalable to next-gen OBO modules at Facebook datacenters aiming to lower the NTF rate and optimally utilizing the available resources. BIM, which is based on Open Compute Platform (OCP) network switches, can be used to troubleshoot 128 QSFP28, 64 QSFP56 or 32 OBO modules simultaneously in under 30 minutes. The tool is easy to implement and capable of also reporting diagnostics on the transceiver such as Transmitter Power, Transmitter Bias Current, Receiver Power, Case Temperature, Bit Error Rate result per channel, Vendor information and Manufacturing part number. This additional test data report along with true failure indication helps optic suppliers gain confidence and build customer credibility. The open-source nature and the universal applicability of this tool offers possibility for other users to adopt and further customize it for their networking needs.
Interaction of Surface Preparation and Cure-Parameters on the Interface Reliability of Flexible Encapsulation in FHE Applications
Authors: Lall Pradeep , Choudhury Padmanava , Miller Scott
Published: November 2021

Flexible devices, considered to be the next wave of electronics industry, require flexible encapsulation for protection while conforming to flexibility-needs in end applications. The characteristics of flexible electronics is not only reduced production cost but also thinner, lightweight and non-breakable which creates a new form application for the electronic devices. One such application is use to electronic devices in daily environment to monitor the vitals of one’s body. These devices are often expose to dust, sweat and moisture also they are generally subjected to flexing and folding motion which accrues stresses in those devices. These stresses and the harsh environment are often mitigated by using potting compounds, encapsulants to improve their survivability of the devices. In our study, we have chosen five different formulation of encapsulant subjected it various cure profiles to determine the adhesive strength of the various encapsulant. The benchmark peel strength was developed using a FE-model of the AU-biometric band and encapsulant peel strength at experimental conditions were compared to give us the best performing material. This paper includes the sample geometry which consists of five different encapsulants and two different substrate namely, polyimide and pet tested at four different cure schedule while the substrates were cleaned using two different cleaning methods. The encapulants are compared among each other to create a rank for possible future applications in FHE devices.
Property Evolution and Reliability of Underfills Under Sustained High Temperature Storage
Authors: Lall Pradeep , Kasturi Madhu , Wu Haotian , Suhling Jeff , Davis Edward
Published: November 2021

Automotive underhood electronics may be exposed to high temperature in the neighborhood of 100°C–200°C. Property evolution may impact reliability and accuracy of predictive models to assure desired use life. In this paper, evolution of properties of two underfill material properties are studied using DMA (Dynamic Mechanical Analyzer). The underfills are exposed to three different operational temperatures in the range of 100°C to 140°C for the measurements. The dynamic mechanical properties such as storage modulus (E′), loss modulus (E″), tangent delta (tan δ), and respective glass transition temperatures (Tg) are studied using DMA. Study of viscoelastic behavior of underfills is achieved by performing TTS (time-temperature superposition) experiments at 7 discrete frequencies 0.1, 0.21, 0.46, 1, 2.15, 4.64, and 10 Hz using DMA in three-point bend mode. From the selected reference temperatures, the master curves were constructed for storage moduli, loss moduli and tan delta as a function of frequency using TTS results. Using the WLF (Williams-Landel-Ferry) equation, the shift factors as a function of temperature were determined along the frequency axis. The relaxation modulus as a function of temperature and time can be obtained using the master curves of storage and loss moduli. A simple and detailed procedure has been established to find the Prony series constants.
Additively Printed Flexible Temperature Sensor for Wearable Applications
Authors: Lall Pradeep , Jang Hyesoo , Narangaparambil Jinesh , Goyal Kartik , Hill Curtis
Published: November 2021

The flexible sensor has the capability to be mounted on any curved surfaces of applications and be used for portable devices. Additively printed sensors have received attention owing to their compact design and ability of application to non-planar surfaces. Wearable applications require capability of integration into a variety of surfaces with ability to flex, fold, twist and stretch under the stresses of daily motion. There is scarcity of data on the interaction of the process parameters with the realized performance. In addition, there is need for data focused on sensor accuracy, repeatability, and reliability. In this study, experimental analysis on function of the fabricated sensing board is conducted. The temperature sensors are made by direct write printing method with nScrypt printer. A calibration of the sensors has been conducted to confirm that resistance is well related to actual temperature and find TCR (temperature coefficient to resistance). The evolution of resistance has been correlated with the environmental temperature. The sensor hysteresis has been quantified using upswing and downswing of the environmental temperature. In addition, the effect of humidity on the temperature sensor accuracy and performance has been quantified. The effect of a polymide coat on the sensor to prevent humidity effects has also been quantified.
Mechanical noise and vibration control
Authors: Lilly Jerry G.
Published: November 2021

This presentation is intended to provide basic training for entry-level and early-career acoustical consultants in the area of mechanical equipment noise and vibration control in buildings. The seminar will address the following topics: (1) general design guidelines and noise and vibration criteria; (2) basics of fan, pump, and compressor noise generation and vibration isolation; (3) HVAC ductwork and piping design; (4) evaluating manufacturer sound data; (5) laboratory measurement of mechanical equipment; and (6) conducting field measurements and calculations. References to past projects from the speaker’s 40 + years of consulting experience will be included to emphasize specific points, as appropriate.
Bubble effects on upper ocean acoustics under wind-driven seas
Authors: Deane Grant B. , Vishnu Hari , Chitre Mandar
Published: November 2021

Dense clouds of bubbles—ranging in scale from 10s of micrometers to cm—are generated by breaking waves on wind-driven seas. Wave-induced bubbles increase ocean albedo and play an important role in air-sea exchange processes by enhancing the transfer of gases and generating sea spray aerosol. Because bubbles both scatter sound efficiently and generate pulses of sound on formation, they create important acoustical effects, including the generation of ambient sound, the attenuation and scattering of sound forward scattered from the sea surface, and enhanced surface backscattering at low grazing angles. Examples of these effects will be illustrated along with the treatment of a bubble cloud acoustical scattering regime characterized by low absorption but high phase distortion relevant to high-frequency, coherent acoustic communications. [Work supported by ONR Ocean Acoustics.]
Predictions of acoustic backscattering from oceanic stratification interfaces
Authors: Weidner Elizabeth , Weber Thomas C.
Published: November 2021

The ocean is primarily composed of a series of increasingly dense fluid layers, defined by density stratification interfaces where medium properties, such as temperature and salinity, drive changes in medium density and compressibility. The transport of dissolved constituents (e.g., oxygen, heat, salt) between these oceanic fluid layers is strongly influenced by the intensity of the stratification interface. Active acoustics allow for high resolution observations of these interfaces, offering continuous data collection over broad spatial scales. In this work, we present a one-dimensional acoustic scattering model for predicting acoustic backscatter from stratification interfaces. The model is widely applicable to acoustic water column data collected with ship-mounted sonars and preliminary results, based on hydrographic profiles, suggest that, in many oceanic cases, sound speed perturbations drive the majority of acoustic scattering. Additionally, modeling results predict a frequency modulated backscattering intensity based on the sharpness of the stratification interface, suggesting the potential for remote estimation of medium properties through broadband acoustic inversion.
The impact of lipid shell composition of perfluorocarbon nanodroplets on size distribution and acoustic droplet vaporization and cavitation dynamics
Authors: Welch Phoebe J. , Forest Craig R. , Shi Chengzhi
Published: November 2021

Perfluorocarbon nanodroplets are ultrasound contrast agents that phase transition from liquid to gas when activated by lasers or insonated with a high intensity ultrasound pulse. The dynamics of perfluorocarbon nanodroplets can vary drastically depending on the nanodroplet shell and/or core composition. In this work, we investigated the role of varying lipid shell compositions and how this impacts the acoustic droplet vaporization and inertial cavitation dynamics of these nanodroplets when insonated with high intensity focused ultrasound. We also examined the role of lipid shell composition on the size distribution of these nanodroplets. Nanodroplets with a higher concentration of PEGylated lipids had larger diameters and exhibited greater variance in size distribution. Perfluorocarbon nanodroplets with a lipid shell composed of 50:50 PEGylated to non-PEGylated lipids yielded the highest intensity and duration ultrasound signal as well as the greatest pressure differential between acoustic droplet vaporization onset and inertial cavitation onset. These findings can help guide researchers to fabricate perfluorocarbon nanodroplets with optimized parameters for their specific applications, including ultrasound imaging, drug delivery, and tissue ablation.
Bubble cloud progression in fibrous tissue mimicking hydrogels at different histotripsy sonications
Authors: Nanda Kumar Yashwanth , Singh Zorawar , Wang Yak-Nam , Schade George R. , Kreider Wayne , Bruce Matthew , Vlaisavljevich Eli , Khokhlova Tatiana D. , Maxwell Adam
Published: November 2021

Polyacrylamide-alginate hydrogels (85/15, 90/10, 95/5 by weight ratio) have been developed with similar mechanical and acoustic properties to human benign prostatic hyperplasia tissue. Although the phantoms are similar to other gels in stiffness, they have much greater toughness and require >10 times the dose to liquify by histotripsy. The purpose of this study was to evaluate differences in bubble dynamics and bubble cloud behavior with different histotripsy sonication in the gels, and how these might affect lesion formation. All gels were treated with a 700 kHz histotripsy transducer at pulse repetition frequencies of 10 or 500 Hz and pulse-durations of 20 or 3 cycles at identical acoustic pressures P+ 108 MPa, P− 20 MPa. The bubble cloud generated over 2000 pulses was captured using high-speed camera and were analyzed for bubble density and temporal changes from pulse to pulse. In low-toughness agarose gel, there was a dense cloud formation, leading to a defined lesion as pulse count progressed. In the polyacrylamide-alginate gel, a dense focal cloud surrounded by a sparse uniform cloud towards the transducer was observed throughout, with both PRFs. This sparse cloud potentially explains the increased dosage required to treat hybrid gels. [Work supported by R01-DK119310 and L30-DK122509.]
Histotripsy bubble dynamics in anisotropic hydrogels
Authors: Elliott Jacob C. , Simon Julianna , Arguelles Andrea
Published: November 2021

Collagenous, anisotropic tissues such as tendon have demonstrated resistance to fractionation by histotripsy. B-mode imaging verifies the creation of bubbles, but oscillation and collapse of these bubbles does not cause fractionation. The objective of this work is to evaluate effects of anisotropy on bubble dynamics in tissue-mimicking hydrogels. Polyacrylamide, fibrin, and collagen hydrogels were fabricated. Axial sound speeds were measured in each direction to evaluate degree of anisotropy. Hydrogels were exposed to 1.5-MHz focused ultrasound with 10-ms pulses repeated at 1-Hz with p+ = 89 MPa, p− = 26 MPa. Cavitation activity was monitored with high-speed photography and passive cavitation imaging with a Philips/ATL L7-4 transducer and Vantage® ultrasound system. Preliminary results show violent cavitation activity and rapid fractionation in polyacrylamide, collagen, and fibrin hydrogels which have low degrees of anisotropy (<1.2); such behavior is unlike what is observed in collagenous tissues. To make a gel more similar to collagenous tissues, fibrin gels were dehydrated and a >90% reduction of water content resulted in a 55% reduction in peak cavitation emission energy and a 260% increase in anisotropy. This suggests an influence from anisotropy, and therefore varying axial elastic moduli, on cavitation activity that will be explored further. [Work supported by NIH R21EB027886.]