bluuebunny/crossref_metadata_2025 huggingface dataset:
The Systematic Study of Fan-Out Wafer Warpage Using Analytical, Numerical and Experimental Methods
Authors: Gadhiya Ghanshyam , Rzepka Sven , Otto Thomas , Kersjes Sebastiaan , Fernandes Felandorio
Published: December 2020

Low-Density Fan-Out (LDFO) (or fan-out wafer-level packaging) technologies are getting significant attention for heterogeneous system integration in many applications. Despite many studies, excessive wafer warpage is still a challenge for many process steps in these technologies. Therefore, the systematic study is carried out to understand the physics of wafer warpage focusing on the interactions between the silicon (Si) and the epoxy molding compound (EMC). The study started with analytical calculations and finite element (FE) analyses of simple mold/Si bilayer wafer bow for the initial benchmarking. The actual 8″ mold/Si wafer warpage measurements are performed using a newly developed measurement system featuring a 3-point support and an in-situ temperature measurement platform. The finite element model is calibrated with respect to measured wafer warpage showing bifurcation behavior by incorporating the cure shrinkage, mold layer thickness variation, perturbation force, gravity and the actual mold material properties measured by dynamic mechanical analysis (DMA) and thermomechanical analysis (TMA). Also, the FE models with and without rigid contact support are validated showing a good match with measured wafer bow for different silicon thicknesses. Next, the study was further widened to realistic 12″ reconstituted wafers using the validated FE analysis approach. Interestingly, these wafers also exhibit the bifurcation effect and the bifurcation region is analyzed for the relevant range of die and overmold thicknesses for two mold materials. A virtual design of experiments (DOE) quantified these influences for different die and mold thicknesses, die occupation rate and mold materials. These studies provide good practical guidance for the optimal LDFO design to avoid excessive warpage.
Electromigration Analysis of Solder Joints for Power Modules Using an Electrical-Thermal-Stress Coupled Model
Authors: Kato Mitsuaki , Omori Takahiro , Goryu Akihiro , Fumikura Tomoya , Hirohata Kenji
Published: December 2020

Power modules are being developed with the aim of increasing power output. Achieving this aim requires increased current density in power modules. However, at high current densities, power modules can degrade as a result of electromigration, which is a phenomenon where atoms move due to momentum transfer between conducting electrons and metal atoms. In addition, atoms are also moved by mechanical stress gradients and temperature gradients, so it is necessary to consider the combined effects of electrical, thermal, and mechanical stress.

This report describes an electromigration analysis of solder joints for power modules. First, we validated our numerical implementation and showed that it could reproduce the distributions of vacancy concentrations and hydrostatic stress that were almost the same as those in previous studies. We then describe the effects of electromigration in a single solder joint. Due to the appearance of plastic and creep strains, the rate of increase in vacancy concentration was very slow and inelastic strain grew at an increasing rate. This result indicates that inelastic properties may strongly affect electromigration-induced degradation. Next, we present results for the solder joint with a SiC device and substrate. A current crowding appeared at the edge of the solder joint, and a vacancy concentration gradient was generated in not only the thickness direction but also the longitudinal direction. The absolute value of vacancy concentration increased significantly at the edge and did not reach a steady state even after a long time. These results indicate that peripheral components may strongly affect the electromigration-induced degradation. In addition, we modeled the behavior of metal atoms passing through the interface of the solder joint and simulated the growth of the intermetallic layer by electromigration.
Additive Fabricated Compliant Interconnects: Design, Fabrication and Reliability Effects
Authors: Olatunji Tumininu , Huitink David
Published: December 2020

Electronics packaging development is greatly dependent on the magnitude of interconnect and on-chip stress that ultimately limits the reliability of electronic components. Thermomechanical strains occur because of the coefficient of thermal expansion mismatch from different conjoined materials being assembled to manufacture a device. To curb the effect of thermal expansion mismatch, studies have been done in integrating compliant structures between dies, solder balls, and substrates. Initial studies have enabled the design and manufacturing of these structures using a photolithography approach which involves an increased number of fabrication steps depending on the complexity of the structures. This current study involves the fabrication of these structures using a different approach, utilizing additive manufacturing that reduces the number of fabrication steps required to obtain compliant geometries, while also providing a platform for unique compliant structures. This paper discusses the method of fabrication and analyzes the properties and effects of these interconnect structures on a die. Structural finite element thermal cycling simulations between −40 to 125°C show about a 115% increase in the solder joint fatigue life. Additionally, fabricated test structures created directly on a PCB were experimentally characterized for compliance using a micro-indenter tester, showing a mechanical compliance range of 265.95 to 656.78 μ/N for selected design parameters to be integrated into a test vehicle.
Thermal Model of the Package Integrated Cyclone COoler (PICCO): Achieving High Thermal Conductance Using Swirled Two-Phase Flow
Authors: Miorini Rinaldo L. , Sharar Darin J. , deBock Peter
Published: December 2020

The demand for high power density, therefore high heat dissipation, power electronics modules is propelled by applications such as hybrid transportation and asynchronous power generation, among others. Besides a low thermal resistance, these applications require high thermal capacitance to manage transient operations.

The Package Integrated Cyclone COoler (PICCO) is an additively manufactured, thermal energy storing cooler codesigned by GE Research (GRC) in collaboration with the US Army Research Lab (ARL). The key aspect of PICCO is its capability to swirl a two-phase coolant, i.e. liquid-gas. The centrifugal field creates a radial pressure gradient inducing buoyancy. The strong radial acceleration to which the fluid is subject forces relatively cold flow outward to reach the hot wall, thus boosting the heat transfer, while hot flow and bubbles migrate inward and the two-phase system is nearly isothermal (thermal storage).

The proposed study models the swirled flow in terms of liquid film heat conductance and critical heat flux predictions. The resulting heat transfer coefficient can be applied to the walls of the cyclone and used as a boundary condition for the heat conduction problem through the cyclone wall and the module layers.
Surface Engineering Through Atomic Layer Deposition on Three-Dimensionally Structured Materials
Authors: Quach Nhi V. , Pham Quang N. , Han Ju-Hwan , Suh Youngjoon , Park Jin-Seong , Won Yoonjin
Published: December 2020

Atomic layer deposition (ALD) is effective in depositing conformal thin films, which is highly favorable for coating various patterned surfaces. These coatings serve as barrier layers in addition to surface modifications to improve wettability of porous structures, such as meshes and membrane channels. However, it has been challenging to conformally deposit hydrophilic thin films on three-dimensionally (3D) designed, more complicated architectures. To understand the effect of surface modifications on 3D structures’ surface properties, we deposit thin silica films via ALD on hydrophobic porous media, which is nickel inverse opal structures in this case. The silica thin film is used to improve hydrophilicity without modifying the geometries of the microporous structure such as porosity, pore size, and metal type. We study the consequences of applying silica coatings to the 3D structure in comparison to flat surface counterpart. The hydrophilicity effects of ALD coating on porous structures and flat nickel surfaces are approximately the same with a result of decreasing apparent static contact angle of approximately 30°. In relation, the Fowkes method reveals the surface energy of the ALD silica samples increases by a factor of 1.3. Thermal stability of the coating is tested, revealing a relative degradation with increasing thermal cycling, most likely associated with the adsorption species on the thin film surface. The droplet spreading rate is analyzed in addition to droplet volume loss to estimate the liquid penetration rate into the structure, if any. Condensation rate and condensate growth show that despite having lower droplet nucleation in comparison to a flat surface, the droplet area growth on inverse opal regions is larger. These findings showcase potential improvements to 3D microporous structures by employing ALD coating for fluid transport through the porous media.
PHM Features for Large Circuit Boards to Be Implemented Into Electric Drivetrain Applications
Authors: Otto A. , Kaulfersch E. , Singh P. , Romano C. , Hildebrandt M. , Rzepka S.
Published: December 2020

Canary structures being used as early warning indicators represent an important tool for condition and health monitoring of electronic components and systems. In this paper, printed circuit boards with canary structures based on SMD 2512 ceramic chip resistors with reduced solder pad sizes were studied. Focus of these investigations was set on thermo-mechanical and mechanical stresses caused by passive thermal cycling as well as by vibrational loads. For this purpose, experimental methods such as deformation analysis and accelerated ageing tests as well as finite element based methods were applied. In addition, an outlook on the implementation of these canary structures into dual inverter electronic control boards for electrical powertrain applications will be given.
Investigation Regarding Thermal Resistance of Surface Mount Type Discrete Power Semiconductor Package
Authors: Nishi Koji
Published: December 2020

Power electronics is becoming more important than before with motor application expansion. For size reduction of inverter integrated motor design, accurate temperature prediction of power devices is becoming critical. For up to several hundred-watt motor system, inverter is designed with discrete power devices with standard package. This paper investigates package thermal resistance of a DPAK package as an example. Firstly, three-dimensional heat conduction simulation only with DPAK package model is conducted. It is found that its package thermal resistance changes by ∼6.2°C/W due to boundary condition variation. After that, simulation not only with DPAK package but also with PCB is conducted to understand package thermal resistance of a real system implementation case. It is found that package thermal resistance varies drastically by copper trace size. “Smallest” case with minimum copper traces shows ∼0.9 °C/W higher value than larger copper trace case and shows ∼1.5 °C/W higher value than the case that copper trace fully covers PCB top surface, in the case that horizontal PCB size is 50 × 50 mm.

After that, two types of test boards with different trace size for of n-channel MOSFET with DPAK package are prepared. Measurements are conducted to know package thermal resistance variation by copper trace size. Transient thermal impedance curve is obtained from measurement result and is converted to a cumulative Rth-Cth curve to know and discuss the difference by copper trace size of these two test boards. The difference is also discussed with and compared to that of simulation results.
Lasered Roughness to Increase Wicking Rates in Pin-Fin Microstructure
Authors: Hazra Sougata , Liu Tanya , Asheghi Mehdi , Goodson Kenneth
Published: December 2020

In this study, we demonstrate an inexpensive and fast method of creating hybrid microstructures for enhancement of capillary wicking by using UV laser ablation. We have also experimentally observed that capillary wicking rates are greatly increased by laser-machining induced surface roughness in pin-fin microstructures, and in one case the amount of enhancement was as large as 116%. The capillary wicking enhancement is a strong function of the geometry of the largescale pin-fin microstructures as well as the surface roughness of the flat areas. This study will help lead to the better understanding of capillary wicking in hybrid structures that in turn can assist with more informed designing and optimization processes of evaporator wicks in vapor chambers.
Twist Reliability Assessment of Flexible Battery in Wearable Applications
Authors: Lall Pradeep , Jang Hyesoo , Miller Scott
Published: December 2020

Survivability of thinner power sources such as flexible Li-ion batteries (LIB) when exposed to repeated charge-discharge cycles at different operating temperatures along with small mechanical twisting loads encountered in human body applications is relatively unknown. With the advancements in portable and densely packaged electronics, thin power sources, which are reliable and are needed to sustain the daily stresses of motion. The ability of thin form factors to operate reliably in presence of loads such twisting while simultaneously being exposed to different ambient temperatures is the major concern. Development of meaningful test protocols for reliability of the battery requires the replication of human body motion. A twisting test-stand capable of replicating the stresses of daily motion in a lab-environment has been developed for the test. The battery state assessment analyzer comprises of programmable source meter and electronic load, a multi-channel data acquisition system, LabVIEW user interface. A mechanical bending actuator controlled via microcontroller was used for subjecting the LIBs to bending loads. The microcontroller was programmed in a way such that 60 twisting cycles were performed during every discharge phase. A total of 150 charge-discharge cycles are conducted during the life cycle tests where each cycle is comprised of discharging to full depth, bending during discharging, and charging back to full voltage. The degradation of the batteries has been studied. FEM model has been developed for life prediction of the battery and for assessment of acceleration factors between test conditions and use conditions.
Creep Behavior of Various Materials Within PBGA Packages Subjected to Thermal Cycling Loading
Authors: Fahim Abdullah , Hasan Kamrul , Suhling Jeffrey C. , Lall Pradeep
Published: December 2020

Electronic packages are frequently exposed to a thermal cycling environment in real life applications. Particularly, the plastic ball grid array (PBGA) is one of the most widely used electronic package, and consists of various component materials, e.g. solder joint, silicon die, die attachment adhesive, mold compound, solder mask, etc. All of these materials play a significant role on the reliability of the overall package. Failure under creep deformation is one of the significant failure mode for electronic packages. Hence, it is important to study their creep behavior and evolution under the thermal cycling environment. These changes must be evaluated in order to understand and predict their failure behavior due to creep damage in operation.

In our previous study, evolution of mechanical properties of SAC305 solder joints in a PBGA package up to 250 thermal cycles was evaluated using the nanoindentation technique. In this work, nanoindentation technique was utilized to understand the evolution of creep behavior of the SAC305 solder joint, die attachment adhesive, silicon die, and solder mask material for various durations of thermal cycling. Test specimens were first prepared by cross sectioning a PBGA package to reveal the different materials, followed by surface polishing to facilitate SEM imaging and nanoindentation testing. After preparation, the package samples were thermally cycled from T = −40 to 125 °C in an environmental chamber. At various points in the cycling (e.g. after 0, 50, 100, 250 and 500 cycles), the package was taken out from the chamber, and nanoindentation was performed on above mentioned materials to obtain creep behavior at room temperature (25 °C). From the nanoindentation test data, it was found that creep deformation of SAC305 increased upto 500 cycles. Die attachment and solder mask materials showed initial decrease in creep deformation up to 250 cycles and then increased value at 500 cycles. As expected, the silicon die material does not show any significant change in creep deformation behavior upto 500 cycles.
High Strain Rate Low Temperature Properties for SAC-R After Exposure to Isothermal Aging
Authors: Lall Pradeep , Saha Mrinmoy , Suhling Jeff , Blecker Ken
Published: December 2020

Electronic parts in military, automotive, avionics and space applications may be subjected to sustained operation at high temperature in addition to high strain-rate loads. Parts may be stored in non-climate-controlled enclosures prior to deployment. Earlier studies on undoped SAC alloys have shown that the material properties evolve after prolonged period of storage at even modest temperatures. In order to mitigate the aging effects, a number of alloy formulation have been proposed. Data of the mechanical properties of lead-free solder alloys which is used for interconnection in the electronic packaging at high strain rates and at high storage temperature is very essential for design optimization of electronic package sustainability at extreme temperature environment because the SAC solders have shown to have degradation in mechanical properties at prolonged exposure to storage temperature. Industries have come up with a solution to reduce the degradation using dopants in SAC solder. In this study, a doped SAC solder called SAC-R has been subjected to high strain rate testing after extended storage at temperature of 50°C for 1 month, 2 months and 3 months. Samples with no aging and aged samples for up to 3-months have been subjected to uniaxial tensile tests to measure the mechanical properties of SAC-R for High and Low operating temperature ranging from −65°C to +200°C. The material data has been used to compute the constants for the Anand Visco-Plasticity model. The ability of the model to represent the material constitutive behavior has been quantified by comparing the model predictions of the uniaxial tensile test with the experimental data.
High Strain Rate Mechanical Properties of SAC-Q Between -65°C and +200°C After Exposure to Isothermal Aging
Authors: Lall Pradeep , Mehta Vishal , Suhling Jeff , Blecker Ken
Published: December 2020

In many industries, such as automotive, oil and gas, aerospace, medical technologies, electronic parts can often be exposed to high strain loads during shocks, vibrations and drop-impact conditions. Such electronic parts can often be subjected to extreme low and high temperatures ranging from −65°C to 200°C. Also, these electronic devices can be subjected to strain rates of 1 to 100 per second in the critical environment. Recently, many doped SAC solder alloys are being introduced in the electronic component including SAC-Q, SAC-R, Innolot. SAC-Q is made with addition of Bi in Sn-Ag-Cu composition. Mechanical characteristic results and data for lead-free solder alloys are extremely important for optimizing electronic package reliability, at high temperature storage and elevated strain rates. Furthermore, the mechanical properties of solder alloys can be changed significantly due to a thermal aging, which is causing modification of microstructure. Data for the SAC-Q solder alloy with a high temp aging and testing at extreme low to high operating temperatures are not available. SAC-Q material was tested and analyzed for this study at range of operating temperatures of −65°C to 200°C and at a strain rate up to 75 per second. After the specimens were manufactured and reflowed, specimens were stored at 100°C for the isothermal aging for up to 90 days, before tensile tests were carried out at different operating temperatures. For the wide range of strain rates and test temperatures, stress-strain curves are established. In addition, the measured experimental results and data were fitted to the Anand viscoplasticity model and the Anand constants were calculated by estimating the stress-strain behavior measured in the wide range of operating temperatures and strain rates.
Correlation of Microstructural Evolution With the Dynamic-Mechanical Viscoelastic Properties of Underfill Under Sustained High Temperature Operation
Authors: Lall Pradeep , Kasturi Madhu , Wu Haotian , Davis Ed , Suhling Jeff
Published: December 2020

Automotive underhood electronics are subjected to high operating temperatures in the neighborhood of 150 to 200°C for prolonged periods in the neighborhood of 10-years. Consumer grade off-the shelf electronics are designed to operate at 55 to 85 °C with a lower use-life of 3 to 5 years. Underfill materials are used to provide supplemental restraint to fine-pitch area array electronics and meet the reliability requirements. In this paper, a number of different underfill materials are subjected to automotive underhood temperatures to study the effect of long time isothermal exposure on microstructure and dynamic-mechanical properties. It has been shown that isothermal aging oxidizes the underfill, which can change the mechanical properties of the material significantly. The oxidation of underfill was studied experimentally by measuring oxidation layer thickness using polarized optical microscope. The effect on the mechanical properties was studied using the dynamic mechanical properties of underfill with DMA (Dynamic Mechanical Analyzer). Two different underfill materials were subjected to three different isothermal exposure, which are below, near and above the glass transition temperature of the underfills. The dynamic mechanical viscoelastic properties like storage modulus, loss modulus, tan delta and their respective glass transition temperatures were investigated. Three point bending mode was used in the DMA with a frequency of 1 Hz operating at 3 °C/min.
Reliability Assessment of Cu-Al WB Under High Temperature and High Voltage Bias Application
Authors: Lall Pradeep , Jung Sungmo
Published: December 2020

Electronics in automotive underhood environments may be subjected to high temperature in the range of 125–200°C. Transition to electric vehicles has resulted in need for electronics capable of operation under high voltage bias. Automotive electronics has simultaneously transitioned to copper wire-bond from gold wire-bond for first-level interconnections. Copper has a smaller process window and a higher propensity for corrosion in comparison with gold wire bonds. There is scarce information on the reliability of copper wire bonds in presence of high voltage bias under operation at high temperature. In this paper, a multiphysics model for micro galvanic corrosion in the presence of chlorine is introduced. The diffusion cell is used to measure the diffusivity of chlorine in different pH values and different temperatures. Diffusivity measurements are incorporated into the 3D ionic transport model to study the effect of different environmental factors on the transport rate of chlorine. The tafel parameters for copper, aluminum and intermetallics have been extracted through measurements of the polarization curves. The multiple physics of ionic transport in presence of concentration gradient, potential gradient is coupled with the galvanic corrosion.
Feature Vector Identification and Prognostics of SAC305 PCB’s for Varying Conditions of Temperature and Vibration Loads
Authors: Lall Pradeep , Thomas Tony , Blecker Ken
Published: December 2020

This study focuses on the feature vector identification of SAC305 solder alloy PCB’s of two different configurations during varying conditions of temperature and vibration. The feature vectors are identified from the strain signals, that are acquired from four symmetrical locations of the PCB at regular intervals during vibration. The changes in the vibration characteristics of the PCB are characterized by three different types of experiments. First type of analysis emphasizes the vibration characteristic for varying conditions of acceleration levels keeping the temperature constant during vibration. The second analysis studies the characteristics changes for varying temperature levels by keeping the acceleration levels constant. Finally, the third analysis focuses on the combined changes in temperature and acceleration levels for the board during vibration. The above analyses try to imitate the actual working conditions of an electronic board in an automobile which is subjected to varying environments of temperature and vibration. The strain signals acquired during each of these experiments are compared based on both time and frequency domain characteristics. Different statistical and frequency based techniques were used to identify the variations in the strain signal with changes in the environment and loading conditions. The feature vectors of failure at a constant working condition and load were identified and as an extension to the previous work, the effectiveness of the feature vectors during these varying conditions of temperature and acceleration levels are investigated using the above analyses. The feature vector of a PCB under varying conditions of temperature and load are identified and compared with different operating environments.
Evaluation of the Creep Response of Lead Free Solder Materials Subjected to Thermal Cycling
Authors: Hasan S. M. Kamrul , Fahim Abdullah , Suhling Jeffrey C. , Lall Pradeep
Published: December 2020

In the electronic assembly arena, lead is being targeted due to the concern regarding environmental pollutants. So, the lead-free solder and its reliability are getting highlighted. During qualification testing or actual use lead-free solders in electronic assemblies, they are often subjected to thermal cycling. In the lead-free solder material, microstructural evolution and material property degradation occurs due to the thermal aging phenomena during dwell periods at the high temperature extreme of thermal cycling. In addition, during ramping between low and high temperature extreme, lead-free solders can experience additional aging phenomena. In our prior work, we have compared material properties (stiffness and strength) degradation of lead-free solder materials in isothermal aging and five different thermal cycling exposures. Changes in material properties were higher for all the thermal cycling exposures compared to the aging. In addition, microstructural evolution and material property degradation were exacerbated as the ramp rate decreased in the thermal cycling.

In this study, the creep behavior evolutions occurring in SAC305 lead free solder subjected to isothermal aging and slow thermal cycling exposures have been investigated. Uniaxial test specimens were prepared by reflowing solder in rectangular cross-section glass tubes with a controlled temperature profile. Afterwards, the reflowed samples were exposed to either isothermal aging at 125 °C, or to thermal cycling from −40 to +125 °C, under a stress-free condition (no load) for various durations in an environmental chamber. A slow thermal cycling profile, e.g. 150 minutes cycle with 45 minutes ramps and 30 minutes dwells, was chosen for this study as it was found in our previous work that it caused the most detrimental effects on the mechanical behavior evolution. The thermally exposed samples were isothermally aged for 0, 1, 2, and 5 days; or were thermally cycled for 0, 48, 96, and 240 slow thermal cycles, which had the same aging times at the high temperature extreme of T = 125 °C.

After aging or cycling, creep testing was performed at room temperature on the thermally exposed samples at three different stress levels (10, 12, 15 MPa). The evolutions of the secondary creep strain rate were obtained as a function of the stress level, as well as the net aging time at the high temperature extreme, and then compared. Results showed that secondary creep strain rate increased dramatically with equivalent aging time, and that the degradation effects were larger for slow thermal cycling than for pure aging. For example, the creep rate increased by 3.0–3.4X for 5 days of pure aging at T = 125 °C; while they increased by 10.9–13.1X for 240 thermal cycles, when there had been 5 days of equivalent aging at the T = 125 °C high temperature extreme.
Deformation Behavior of SAC305 Solder Joints With Multiple Grains
Authors: Mondal Debabrata , Fahim Abdullah , Hassan KM Rafidh , Suhling Jeffrey C. , Lall Pradeep
Published: December 2020

Lead-free solder joints are the most widely used interconnects in electronic packaging industries. Usually solder joints in most of the electronic devices are exposed to an environment where variation of temperature exists, which indicates cyclic thermal loading to be a very common type of external loading. Moreover, due to difference in the coefficient of thermal expansion (CTE) among dissimilar contact materials, shear stress develops in junctions under thermal loading, which significantly deteriorates the overall reliability. Hence, characterization of lead-free solder materials under thermal loading is essential to predict the performance and deformation behavior of joints in practical applications. A significant portion of the studies in this field are concerned with thermal loading of lead-free solder interconnects, each of which has a very small diameter, in sub-millimeter range. Although the solder balls have very small dimensions, most of the analyses considered them as a bulk material with homogeneous and isotropic properties. However, with the decrease of specimen dimensions, size effects and material directionality play a significant role in deformation mechanisms. Since a very few grains exist in a small specimen, individual grain properties play a vital role on overall material response. Therefore, modeling from the grain structure and orientation point of view could be an effective and more accurate way to predict solder joint deformation behavior under thermal loading.

In this study, the effect of grain size and orientation of SAC305 is investigated for predicting anisotropic behavior of solder joints under thermal load. A simplified three-dimensional model of beach-ball configuration solder joint was generated and simulated using ABAQUS finite element (FE) software. Experimentally obtained directional properties such as elastic modulus and CTE were assigned to the computational geometry to create material anisotropy. The effects of material anisotropy were studied for varying grain size specimens, as well as for specimens with varying grain orientation.
Comparison of IOTA three-step strategy and logistic regression model LR2 for discriminating between benign and malignant adnexal masses
Authors: Hidalgo Juan José , Llueca Antoni , Zolfaroli Irene , Veiga Nadia , Ortiz Ester , Alcázar Juan Luis
Published: December 2020

Aims: To compare the diagnostic performance of two ultrasound-based diagnostic systems for the classification of benign or malignant adnexal masses, the three-step strategy and the predictive logistic regression model LR2, both proposed by the International Ovarian Tumour Analysis (IOTA) Group. Material and methods: Prospective observational study at a single centre that included patients diagnosed with a persistent adnexal mass by transvaginal ultrasound over a period of two years. They were evaluated by a non-expert sonographer by applying the three-step diagnostic strategy and the LR2 predictive model to classify the masses as benign or malignant. Patients were treated surgically or followed up for at least one year, taking as the standard reference for benignity or malignancy the histological diagnosis of the lesion or ultrasound changes suggestive of malignancy during the follow-up period. Sensitivity, specificity, positive and negative likelihood ratios and overall accuracy of both systems was calculated and compared. Results: One hundred patients were included, with a mean age of 50.6 years (range 18-87). Surgery was performed on 62 (62%) patients and 38 (38%) were managed expectantly. Eighty-three (83%) lesions were benign and 17 (17%) were malignant. The IOTA three-step strategy presented sensitivity of 94.1% (95%CI, 86.7-98.3%) and specificity 97.6% (95%CI, 94.8-99%). The LR2 logistic regression model showed sensitivity 94.1% (95%CI, 73-98.9%) and specificity 81.9% (95%CI 72.3-88.7%). Comparison of the two systems showed a statistically significant dif-ference in specificity in favour of the three-step strategy. Conclusions: The IOTA three-step strategy, in addition to being sim-ple to use in clinical practice, has a high diagnostic accuracy for the classification of benignity and malignancy of the adnexal masses, overtaking that of other predictive models such as the LR2 logistic regression model.
Concurrent Validity Between Electronically Administered Physical Activity Questionnaires and Objectively Measured Physical Activity in Danish Community-Dwelling Older Adults
Authors: Larsen Rasmus T. , Korfitsen Christoffer B. , Juhl Carsten B. , Boje Andersen Henning , Langberg Henning , Christensen Jan
Published: December 2020

Aim: To investigate the concurrent validity of the International Physical Activity Questionnaire-short form (IPAQ-SF) and the Nordic Physical Activity Questionnaire-short (NPAQ-short) when compared with objectively measured daily steps among older adults. Methods: Spearman’s ρ between IPAQ-SF and NPAQ-short and objectively measured steps using Garmin Vivofit 3 physical activity monitors. Results: A total of 54 participants were included. The IPAQ-SF subscales’ moderate physical activity (PA), moderate to vigorous PA (MVPA), and sedentary time showed little or no correlation with daily steps. The NPAQ-short subscales’ vigorous PA, moderate PA, and MVPA showed little or no correlation. The IPAQ-SF subscales’ vigorous PA and walking showed fair correlation. Only the IPAQ-SF metabolic equivalent of task minutes showed moderate to good correlation with daily steps. The IPAQ-SF categories and NPAQ-short categorization of World Health Organization compliance were significantly different, but the magnitudes were small and distributions indicated problems with the categorization. Conclusion: The concurrent validity is low, as the scores did not reflect objectively measured daily steps.
Femtosecond quantification of void evolution during rapid material failure
Authors: Coakley James , Higginbotham Andrew , McGonegle David , Ilavsky Jan , Swinburne Thomas D. , Wark Justin S. , Rahman Khandaker M. , Vorontsov Vassili A. , Dye David , Lane Thomas J. , Boutet Sébastien , Koglin Jason , Robinson Joseph , Milathianaki Despina
Published: December 2020

Ultrabright x-rays capture the sequence of material damage accumulation during high strain rate catastrophic failure.
Rewritable color nanoprints in antimony trisulfide films
Authors: Liu Hailong , Dong Weiling , Wang Hao , Lu Li , Ruan Qifeng , Tan You Sin , Simpson Robert E. , Yang Joel K. W.
Published: December 2020

Large refractive index changes in Sb
2
S
3
phase-change material promise nonvolatile ultrathin displays.
The nuclear DICER–circular RNA complex drives the deregulation of the glioblastoma cell microRNAome
Authors: Bronisz A. , Rooj A. K. , Krawczyński K. , Peruzzi P. , Salińska E. , Nakano I. , Purow B. , Chiocca E. A. , Godlewski J.
Published: December 2020

A novel circRNA withholds the microRNA assembly line by arresting the manufacturing foreman in the nucleus of a cancer cell.
Metasurface enabled quantum edge detection
Authors: Zhou Junxiao , Liu Shikai , Qian Haoliang , Li Yinhai , Luo Hailu , Wen Shuangchun , Zhou Zhiyuan , Guo Guangcan , Shi Baosen , Liu Zhaowei
Published: December 2020

Remotely switchable edge imaging is demonstrated on the basis of the metasurface illuminated by polarization-entangled photons.
Modeling the breakup of tabular icebergs
Authors: England Mark R. , Wagner Till J. W. , Eisenman Ian
Published: December 2020

New model of giant Antarctic icebergs produces simulations that match satellite observations, with implications for climate.
Heterogeneous sensing in a multifunctional soft sensor for human-robot interfaces
Authors: Kim Taekyoung , Lee Sudong , Hong Taehwa , Shin Gyowook , Kim Taehwan , Park Yong-Lae
Published: December 2020

Heterogeneous sensing mechanisms enabled a multifunctional compact soft sensor to decouple multiple deformation modes.
Skin-inspired quadruple tactile sensors integrated on a robot hand enable object recognition
Authors: Li Guozhen , Liu Shiqiang , Wang Liangqi , Zhu Rong
Published: December 2020

A robot hand integrated with quadruple tactile sensors can recognize a diverse set of objects for garbage sorting.
Acute nephrotoxicity and neurotoxicity associated with concentrated star fruit juice consumption
Authors: Prado de Negreiros Nogueira Maduro Isolda , Brandão Alba Regina Jorge , Israel Karla Cristina Petruccelli
Published: December 2020

Star fruit toxicity has been hugely described in patients with chronic kidney disease, either on conservative or renal replacement therapy. This is a case report of a man, without prior kidney or neurological dysfunction, who appeared to develop nephrotoxicity and neurotoxicity less than 12 hours after drinking concentrated star fruit juice (approximately 20 units of the fruit). He received timely renal replacement therapy and renal function fully recovered after discharge.
Adult male patient with severe intellectual disability caused by a homozygous mutation in the HNMT gene
Authors: Verhoeven Willem M A , Egger Jos I M , Janssen Paddy K C , van Haeringen Arie
Published: December 2020

Histamine is involved in various physiological functions like sleep–wake cycle and stress regulation. The histamine N-methyltransferase (HNMT) enzyme is the only pathway for termination of histamine neurotransmission in the central nervous system. Experiments with HNMT knockout mice generated aggressive behaviours and dysregulation of sleep–wake cycles. Recently, seven members of two unrelated consanguineous families have been reported in whom two different missense HNMT mutations were identified. All showed severe intellectual disability, delayed speech development and mild regression from the age of 5 years without, however, any dysmorphisms or congenital abnormality. A diagnosis of mental retardation, autosomal recessive 51 was made. Here, we describe a severely mentally retarded adolescent male born from second cousins with a homozygous mutation in HNMT. His phenotypic profile comprised aggression, delayed speech, autism, sleep disturbances and gastro-intestinal problems. At early age, regression occurred. Treatment with hydroxyzine combined with a histamine-restricted diet resulted in significant general improvement.
COVID-19-associated takotsubo cardiomyopathy
Authors: Gomez Joanne Michelle Dumlao , Nair Gatha , Nanavaty Prema , Rao Anupama , Marinescu Karolina , Suboc Tisha
Published: December 2020

The novel COVID-19 has had an unprecedented and devastating spread internationally. COVID-19 infection can lead to a number of cardiovascular sequelae, including heart failure, which may portend worse clinical outcomes. Here, we report a rare case of a 57-year-old woman who developed acute left ventricular systolic dysfunction with apical ballooning consistent with takotsubo cardiomyopathy (TCM), and mixed cardiogenic and septic shock in the setting of COVID-19 disease. We briefly review the pathophysiology and diagnosis of TCM (also described as apical ballooning syndrome and stress-induced cardiomyopathy). Additionally, this case highlights the importance of a multidisciplinary approach to clinical decision-making and resource allocation in diagnosis and management of critical illness in the setting of the ongoing international COVID-19 pandemic.
‘Should have gone to …’: bilateral papilloedema with normal CSF pressure due to vestibular schwannoma
Authors: Ronan Geoffrey Peter , Gailani Gaafar , Costello Ciara , Sweeney Brian
Published: December 2020

A 24-year-old woman presented with bilateral blurring of her distance vision and ‘dizzy spells’. She had no other neurological symptoms or medical history. She consulted an optometrist, and optical coherence tomography (OCT) was performed, which demonstrated papilloedema. She was referred to the local eye clinic for assessment and from there was referred for neurological assessment.

Her initial investigations revealed no abnormalities, and brain imaging was reported to be normal. In the absence of an alternative diagnosis, idiopathic intracranial hypertension (IIH) was considered and a lumbar puncture was performed. This showed elevated protein but normal cerebrospinal fluid (CSF) pressure. MRI of the brain the next day revealed a large cerebellopontine lesion in keeping with vestibular schwannoma. She was referred to neurosurgery for operative management.

This case highlights three interesting points: the aetiology of her papilloedema without raised intracranial pressure, the decision to perform a lumbar puncture in suspected IIH and community OCT as a clinical adjunct.
Spontaneous pneumomediastinum, pneumothorax and subcutaneous emphysema in COVID-19 pneumonia: a rare case and literature review
Authors: Elhakim Tarig Sami , Abdul Haleem S , Pelaez Romero Carlos , Rodriguez-Fuentes Yoandy
Published: December 2020

Spontaneous pneumomediastinum (SPM) and pneumothorax (PNX) unrelated to positive pressure ventilation has been recently reported as an unusual complication in cases of severe COVID-19 pneumonia. The presumed pathophysiological mechanism is diffuse alveolar injury leading to alveolar rupture and air leak. We present a case of COVID-19 pneumonia complicated on day 13 post admission by SPM, PNX and subcutaneous emphysema in a patient with no identifiable risk factors for such complication. The patient received medical treatment for his COVID-19 infection without the use of an invasive or non-invasive ventilator. Moreover, he is a non-smoker with no lung comorbidities and never reported a cough. He was eventually discharged home in stable condition. A comprehensive literature review revealed 15 cases of SPM developing in patients with COVID-19 pneumonia.
Histamine causes an imbalance between pro-angiogenic and anti-angiogenic factors in the retinal pigment epithelium of diabetic retina via H4 receptor/p38 MAPK axis
Authors: Lee Byung Joo , Byeon Hye Eun , Cho Chang Sik , Kim Young Ho , Kim Jin Hyoung , Che Jeong-Hwan , Seok Seung Hyeok , Kwon Jung-Won , Kim Jeong Hun , Lee Kihwang
Published: December 2020

Introduction

Systemic histaminergic activity is elevated in patients with diabetes mellitus. There are a few studies suggesting that histamine is implicated in the pathogenesis of diabetes, but the exact role of histamine in the development of diabetic retinopathy is unclear. The aim of this study was to investigate the role of histamine receptor H4 (HRH4) in the regulation of retinal pigment epithelium (RPE)-derived pro-angiogenic and anti-angiogenic factors under diabetic conditions.

Research design and methods

The levels of vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), histamine and histidine decarboxylase (HDC) in the serum and vitreous samples of patients with diabetes were compared with those of patients without diabetes. The effect of hyperglycemia on expression levels of HRH4, VEGF, IL-6 and pigment epithelium-derived factor (PEDF) in the RPE was determined. The role of HRH4 in high glucose-induced regulation of VEGF, IL-6 and PEDF in ARPE-19 cells and the underlying regulatory mechanism were verified using an RNA interference-mediated knockdown study.

Results

The serum and vitreous levels of VEGF, IL-6, histamine and HDC were more increased in patients with diabetic retinopathy than in patients without diabetes. HRH4 was overexpressed in RPE both in vitro and in vivo. Histamine treatment upregulated VEGF and IL-6 and downregulated PEDF expression in ARPE-19 cells cultivated under hyperglycemic conditions. Hyperglycemia-induced phosphorylation of p38 and subsequent upregulation of VEGF and IL-6 and downregulation of PEDF were dampened by small interfering RNA-mediated knockdown of HRH4 in ARPE-19 cells.

Conclusions

Taken together, HRH4 was a critical regulator of VEGF, IL-6 and PEDF in the RPE under hyperglycemic conditions and the p38 mitogen-activated protein kinase pathway mediated this regulatory mechanism.
Person-centered diabetes care and patient activation in people with type 2 diabetes
Authors: Rutten Guy E H M , Van Vugt Heidi , de Koning Eelco
Published: December 2020

Introduction

The American Diabetes Association and the European Association for the Study of Diabetes advocate a person-centered approach to enhance patient engagement in self-care activities. To that purpose, people with diabetes need adequate diabetes knowledge, motivation, skills and confidence. These prerequisites are captured by the concept ‘patient activation’. The Dutch Diabetes Federation implemented a person-centered consultation model for the annual diabetes review. To assess its relationship with patient activation, we measured thechangein patient activation, and in person and disease-related factors in people with type 2 diabetes after their second person-centered annual review.

Research design and methods

Observational study in 47 primary care practices and six outpatient hospital clinics. Follow-up: 1 year. From 2.617 people with diabetes and capable of completing questionnaires (no additional exclusion criteria) 1.487 (56.8%) participated, 1366 with type 2 diabetes. Main outcome: patient activation (13-item Patient Activation Measure, score 0–100). Before the first and after the second review, participants completed questionnaires. Medical data were retrieved from electronic records. We performed a repeated measure analysis using a linear mixed model in 1299 participants, who completed the first set of questionnaires.

Results

In 1299 participants (41.6% female, mean age 66 years, median diabetes duration 10 years, median glycated hemoglobin (HbA1c) 6.8%/51 mmol/mol), the mean baseline activation level was 58.9 (SD 11.7). Independent of actual diabetes care, activation levels increased 1.53 units (95% CI 0.67 to 2.39, p=0.001). Several diabetes perceptions improved significantly; diabetes distress level decreased significantly. Body mass index (−0.22, 95% CI −0.33 to −0.10, p<0.001) and low-density lipoprotein cholesterol (−2.71 mg/dL, 95% CI −4.64 to −0.77, p=0.004) decreased, HbA1c increased 0.08% (95% CI 0.03 to 0.12) (p=0.001).

Conclusions

Person-centered diabetes care was associated with a slightly higher patient activation level, improved diabetes perception and small improvements in clinical outcomes. Person-centered care may enhance patient engagement, but one should not expect substantial improvement in patient outcomes in the short term.