bluuebunny/crossref_metadata_2025_split huggingface dataset:
Package-level Evaluation System for 3D Thermal Modelling
Authors: Parameswaran Suresh , Refai-Ahmed Gamal , Ramalingam Suresh , Chang Jonathan 
Published: November 2024

Abstract
Thermal modelling is a very important aspect of the thermal management of semiconductor chips. Developing a reliable 3D thermal model is critical. The 3D model will provide a 3-dimensional representation of the thermal behavior within the chip. 3-dimensional heat generation, distribution and measurement are required for this purpose. In this paper, we present a versatile 3D thermal evaluation vehicle that can serve as an important tool in addressing the above requirement. We have developed two generations of semiconductor chips with thermal evaluation capabilities (2D and 3D) to address the above needs. The chip forms the heart of the thermal evaluation system. The architecture, implementation, operation details, programming aspects and usage model of the 3D thermal evaluation tool are covered in this paper. The usage of the evaluation system in developing a 3D thermal model is covered. This chip has a simple implementation and is easy to program and test — yet has substantial 3D thermal modelling and evaluation capabilities. The applications include the following:
• 3D modelling of thermal behavior of semiconductor chips in development, to evaluate architecture/floorplan
• Calibrating 3D thermal simulation results against chip-level measurement data
• Use 3D thermal modelling to address package and cooling solution development
The chip has ability to do automated on-chip measurements through a test-friendly interface and has been tested on a simple and inexpensive test-platform. A large number of heating profiles were programmed, thermal data was collected and analyzed from this thermal evaluation system. Simulations were also done to model the thermal behavior in each of the above-mentioned cases. Comparison of measured data to numerical model based simulation results were done in each case. It is concluded that this evaluation vehicle can play a significant role in the 3D thermal modelling of a semiconductor chip which can be used throughout its development cycle — architecture, floor planning, cooling solutions, package development, and more.
Effect of Bismuth Concentration on the High Strain Rate Characteristics of Sn-Ag-Cu Solders and Analysis of High-g Level Shock Damage During Extended Sustained Operation at 100°C
Authors: Lall Pradeep , Mehta Vishal , Suhling Jeff , Locker David 
Published: November 2024

Abstract
Electronic components commonly face elevated strain loads in industries such as automotive, oil & gas, and aerospace due to shocks, vibrations, and drop-impact scenarios. These components are routinely exposed to a wide range of surrounding temperatures, fluctuating between −65°C and 200°C. Moreover, they may encounter high strain rates, varying from 1 to 100 per second. The solder joint, being one of the weakest links in electronic components/assemblies, is a crucial consideration. The industry has experimented with dopant addition to SAC solders in an effort to mitigate the harmful effects of prolonged exposure to high temperatures. Recently, various doped solder alloys like SAC-Q, SAC-R, M758, etc., have been introduced into electronic components, incorporating elements such as Bismuth, Nickel, and Antimony as dopants. The current literature does not adequately establish the mechanical characteristics of solder alloys at both very low and high working temperatures, especially for long aging times with high-temperature storage. According to JEDEC standard JESD22-B111 (2003), which defines a test board dimension of 132 × 77 × 1.6 mm, published research frequently focuses on the assessment of PCB-Package assemblies under drop/shock circumstances. Numerous research articles on Drop/Shock events contain investigations using Finite Element analysis that simply take into account the elastic characteristics of solder materials. Tensile specimens from different SAC Solders and subjected to testing at operational temperatures spanning from −65°C to 200°C. The tests are conducted at strain rates of up to 75 per second, and the specimens undergo isothermal aging for up to 1 year at a storage temperature of 100°C. The obtained experimental data is then fitted to the Anand viscoplasticity model. Based on trends of properties vs Bi% and, thermal degradation rates vs Bi%, prediction of mechanical properties of doped SAC solder containing higher Bismuth% (e.g. SAC + 4% Bismuth) was carried out. Anand constants are derived for tested and predicted solders, varying aging durations and subsequently applied to explore the viscoplastic behavior of solder joints. Additionally, FE analyses for drop/shock events at 1500g are conducted for various conditions involving the assembly of CABGA208 packages with the PCB (77 × 77 × 1 mm) - dimensions according to latest JEDEC standard JESD22-B111A (2016).
Sequential High Temperature and Hygrothermal Exposure on the Evolution of Interfacial Fracture Toughness of TIM-Copper and EMC Interfaces
Authors: Lall Pradeep , Kasturi Madhu 
Published: November 2024

Abstract
In automotive electronics, where high-performance semiconductors are increasingly utilized for advanced driver assistance systems, effective thermal management is crucial to optimize performance and integration density. One significant aspect is managing thermal interface materials (TIM) to enhance heat dissipation from chips to packages and to heat sinks. Exposure to automotive conditions, characterized by wide temperature ranges and humidity conditions, can lead to early fractures at TIM-to-Copper interfaces, escalating thermal resistance and device thermal runaway. The ongoing downsizing and integration of semiconductor devices has resulted in an increase in heat generated per unit volume of the chip. Insufficient understanding of the development of TIM material fracture toughness during extensive environments in automotive applications hampers the creation of predictive models for estimating time to failure. This paper aims to investigate the impact of temperature storage, and hygrothermal exposure on TIM-Copper and EMC-Substrate interfaces, along with evolving fracture toughness, to develop reliable damage models for assessing performance degradation and predicting interface survivability. The bi-material samples are stored first at high temperatures of between 100°C and 150°C for 60 days then stored in a humidity chamber for moisture absorption at 85°C/85% RH, this is called the sequential exposure. The bi-material samples are subjected to monotonic and fatigue loading to measure mode-1 and mode-2 critical stress intensity factors and Paris’s Power Law Exponents. And, the thermal diffusivity, activation energy, and acceleration factors are being investigated for hygrothermal exposure. The % weight loss/gain of the TIMs for all exposed conditions are presented.
Comparative Performance Analysis of Screen-Printed Structures on PET and BPET Substrates Utilizing Low-Temperature ECA and MACA for SMD Component Attachment
Authors: Lall Pradeep , Kulkarni Shriram , Miller Scott 
Published: November 2024

Abstract
Non-sustainable substrates, such as PET and PI, are used for the additive fabrication of FHE due to their excellent thermal, dimensional stability, and mechanical strength. However, their environmental impact is high due to minimal degradation even after decades in landfills. There is a growing global push for sustainable solutions for printed electronics. Recent studies indicate that alternatives like bio-based PET, polylactic acid (PLA), and regenerated cellulose film, all derived from renewable resources, might not only match but, in some instances, surpass the performance of traditional PET. While these materials show promise in certain environments, comprehensive research on their adaptability across various conditions remains inadequate. This research addresses these concerns, focusing on assessing the performance of bio-based PET substrates in FHE applications and comparing the performance with traditional PET substrates. Research Objectives include — (a) To understand the significance of Flexible Hybrid Electronics in the context of sustainable and environmentally friendly electronics. (b) To determine the compatibility and performance of the biodegradable PET substrate during the screen-printing process, especially while printing with water-based inks. (c) To test the performance of printed circuits and calculate the error percentage between the actual and simulated performance.
Warpage Prediction Improvements for Thin Package-on-Package Architectures
Authors: Kothari Nakul , Dhandapani Karthikeyan , Lee Sangjae (Brandon) , Aldrete Manuel , Puliyath Nidheesh 
Published: November 2024

Abstract
The Package-on-Package (PoP) architecture gained widescale popularity for its relatively lower power consumption and smaller form-factor compared to traditional flip-chip (FC) packages and wafer level FC packages. This was because it effectively shortened the interconnection distance between processor chip and low power double data rate (LPDDR) memory. While the extent of CTE mismatch increased in this architecture, posing significant warpage driven yield loss, researchers have successfully developed finite elements-based simulation methods to predict warpage accurately. Some of the regular Finite Element warpage modeling assumptions made for a traditional Flip Chip Package-on-Package (FC PoP) architectures fail when it comes to thinner PoP architectures. The significantly reduced overall package height for thinner PoP architecture has made its warpage behavior extremely sensitive to the extent of copper content in the package. This high sensitivity is what makes finite elements modeling based warpage prediction challenging. The limited body of published work in this area does point to use of process-based approach for warpage prediction. While promising results and methods have been reported, this methodology is found to be quite cumbersome. Also, the accuracy of the warpage prediction at Room Temperature (RT) and High Temperature (HT) is found to be extremely reliant on one having full access to the detailed process steps which often changes from OSAT vendor to OSAT vendor, and many times deemed confidential, making this approach even more challenging. This paper demonstrates a modified version of the traditional End-of-Line (EoL) Finite Elements based simulation approach to predict warpage shape and magnitude for an already highly sensitive thin PoP architectures. A detailed methodology has been described, alongside step-by-step comparison of warpage prediction improvements from the conventional method to the modified version.
Adherence Support Strategies for Physical Activity Interventions in People With Chronic Musculoskeletal Pain—A Systematic Review and Meta-Analysis
Authors: Heisig Julia , Lindner Nicole , Kornder Nele , Reichert Wiebke , Becker Annette , Haasenritter Jörg , Viniol Annika , van der Wardt Veronika 
Published: November 2024

Background: Chronic musculoskeletal (MSK) pain significantly impacts individuals’ quality of life. Regular physical activity is an important key to therapy. However, adherence to exercise is often below the intended levels. This systematic review aims to assess the effectiveness of adherence support strategies in physical activity randomized controlled trials (RCTs) for patients with chronic MSK pain, to address the challenge of motivation and adherence in this population. Methods: Ovid and CINAHL databases were searched for MSK “chronic pain,” “adherence” and “physical activity” (in various synonyms) for RCTs with a follow-up of at least 6 months. After a screening process that included several team members, a narrative synthesis and a meta-analysis on adherence and effect sizes of different outcomes were performed. Results: An initial database output of 5816 articles resulted in 76 RCTs that remained for analysis. These RCTs showed high heterogeneity of intervention design and outcome data. Adherence to exercise varied widely, with 21 RCTs achieving rates of 80% or higher using strategies like education, goal setting, self-monitoring, and personal feedback. The meta-analysis, based on 29 out of 76 RCTs, indicated a nonsignificant correlation between adherence levels and an improved outcome (eg, pain or quality of life). No individual strategy emerged as superior, emphasizing the complexity and diversity of intervention designs. Conclusions: This review offers strategies, such as information/education and individual goal setting/feedback that may be beneficial for enhancing physical activity in patients with chronic MSK pain. Future research should focus on including promising adherence support strategies and providing data for adherence calculations.
Exploring the interplay between yeast cell membrane lipid adaptation and physiological response to acetic acid stress
Authors: Wu Fei , Bettiga Maurizio , Olsson Lisbeth 
Published: November 2024

ABSTRACT

Acetic acid is a byproduct of lignocellulose pretreatment and a potent inhibitor of yeast-based fermentation processes. A thicker yeast plasma membrane (PM) is expected to retard the passive diffusion of undissociated acetic acid into the cell. Molecular dynamic simulations suggest that membrane thickness can be increased by elongating glycerophospholipids (GPL) fatty acyl chains. Previously, we successfully engineered
Saccharomyces cerevisiae
to increase GPL fatty acyl chain length but failed to lower acetic acid net uptake. Here, we tested whether altering the relative abundance of diacylglycerol (DAG) might affect PM permeability to acetic acid in cells with longer GPL acyl chains (DAG

EN

). To this end, we expressed diacylglycerol kinase α (
DGKα
) in DAG

EN

. The resulting DAG

EN

_Dgkα strain exhibited restored DAG levels, grew in medium containing 13 g/L acetic acid, and accumulated less acetic acid. Acetic acid stress and energy burden were accompanied by increased glucose uptake in DAG

EN

_Dgkα cells. Compared to DAG

EN

, the relative abundance of several membrane lipids changed in DAG

EN

_Dgkα in response to acetic acid stress. We propose that the ability to increase the energy supply and alter membrane lipid composition could compensate for the negative effect of high net acetic acid uptake in DAG

EN

_Dgkα under stressful conditions.

IMPORTANCE
In the present study, we successfully engineered a yeast strain that could grow under high acetic acid stress by regulating its diacylglycerol metabolism. We compared how the plasma membrane and total cell membranes responded to acetic acid by adjusting their lipid content. By combining physiological and lipidomics analyses in cells cultivated in the absence or presence of acetic acid, we found that the capacity of the membrane to adapt lipid composition together with sufficient energy supply influenced membrane properties in response to stress. We suggest that potentiating the intracellular energy system or enhancing lipid transport to destination membranes should be taken into account when designing membrane engineering strategies. The findings highlight new directions for future yeast cell factory engineering.
Tail-specific protease is an essential
Chlamydia
virulence factor that mediates the differentiation of elementary bodies into reticulate bodies
Authors: Banerjee Arkaprabha , Jacobs Kaylee R. , Wang Yihui , Doud Emma H. , Toh Evelyn , Stein Barry D. , Mosley Amber L. , Zhong Guangming , Morrison Richard P. , Morrison Sandra G. , Hu Shuai , Brothwell Julie A. , Nelson David E. 
Published: November 2024

ABSTRACT

Tail-specific proteases (Tsp) are members of a widely distributed family of serine proteases that commonly target and process periplasmic proteins in Gram-negative bacteria. The obligately intracellular, Gram-negative
Chlamydia
encode a highly conserved Tsp homolog whose target and function are unclear. We identified a
Chlamydia muridarum
mutant with a nonsense mutation in
tsp
. Differentiation of the
tsp
mutant elementary bodies into vegetative reticulate bodies was delayed at 37°C and completely blocked at 40°C. Tsp localized to
C. muridarum
cells but was not detected outside the inclusion, suggesting that it targets chlamydial rather than host proteins. The abundance of key chlamydia outer membrane complex and virulence-related proteins differed in wild-type and
tsp
mutant elementary bodies, consistent with the possibility that Tsp regulates developmental cycle progression. The altered abundances of chlamydial structural and virulence factors could explain why the mutant, but not an isogenic recombinant with wild-type
tsp
, was highly attenuated in a mouse intravaginal infection model. Thus, chlamydial Tsp is required for timely differentiation of elementary bodies into reticulate bodies
in vitro
and is an essential virulence factor
in vivo
.
Gene expression profiling reveals host defense strategies for restricting
Candida albicans
invasion and gastritis to the limiting ridge of the murine stomach
Authors: Zeise Karen D. , Falkowski Nicole R. , Metcalf Joseph D. , Brown Christopher A. , Huffnagle Gary B. 
Published: November 2024

ABSTRACT

Candida albicans
is a fungal constituent of the human gastrointestinal microbiota that can tolerate acidic environments like the stomach, where it can be associated with ulcers and chronic gastritis. In mice,
C. albicans
induces gastritis without concurrent intestinal inflammation, suggesting that the stomach is particularly prone to fungal infection. We previously showed that
C. albicans
invasion in the limiting ridge does not extend to or elicit an inflammatory response in the adjacent glandular region, indicating regionalized gastritis in the murine stomach. However, the molecular pathways involved in the host response to
C. albicans
specifically in the limiting ridge have not been investigated. Here, we found that gastric dysbiosis was associated with
C. albicans
limiting ridge colonization and gastritis. We isolated the limiting ridge and evaluated the expression of over 90 genes involved in mucosal responses.
C. albicans
infection triggered a type 3 immune response marked by elevated
Il17a
,
Il17f
,
Il1b
,
Tnf
, and
Il36g
, as well as an upregulation of
Il12a
,
Il4
,
Il10
, and
l13
. Chemokine gene induction (including
Ccl2
,
Ccl3
,
Ccl4
,
Ccl1l
,
Cxcl1
,
Cxcl2
,
Cxcl9
, and
Cxcl10
) coincided with an influx of neutrophils, monocytes/macrophages, and eosinophils. Hyphal invasion caused tissue damage, epithelial remodeling, and upregulation of genes linked to epithelium signaling and antimicrobial responses in the limiting ridge. Our findings support a need for continued exploration into the interactions between the immunological milieu, the host microbiota, and clinical interventions such as the use of antibiotics and immunotherapeutic agents and their collective impact on invasive candidiasis risk.
Applying Beer’s Law in the undergraduate cell biology laboratory: examining the mathematical relationship between optical density, cell concentration, and cell size using budding yeast
Authors: Brito Stacey O. , Rohan Wryn P. , Buffum-Robbins Isobel , Reyes Osorio Patricia Ruby , Tribble Andrea , Segarra Verónica A. 
Published: November 2024

ABSTRACT

Undergraduate students majoring in the life sciences benefit from experience with data analyses that connect mathematical calculations to the biological systems they are studying. Monitoring the optical density and cell number of
Saccharomyces cerevisiae
liquid cultures allows students to gain quantitative experience generating standard curves and trendlines that capture the relationship between optical density and cell concentration for a given
S. cerevisiae
strain. Data comparisons across multiple strains can yield insights into the biophysical properties of cells that drive light absorbance and scattering. In this Tips and Tools article, we share a laboratory module that allows students to experience cell biology tools, laboratory measurements, and data analysis to determine the mathematical relationship between optical density and cell concentration in liquid microbial cultures. This module could be integrated into undergraduate classes ranging from general biology to upper-level cell biology or microbiology and can be a starting point for more complex investigations of microbial growth.
Novel virulence determinants in VP1 regulate the assembly of enterovirus-A71
Authors: Zhang Wenjing , Li Quanjie , Yi Dongrong , Zheng Ruifang , Liu Guihua , Liu Qian , Guo Saisai , Zhao Jianyuan , Wang Jing , Ma Ling , Ding Jiwei , Zhou Rui , Ren Yongcheng , Sun Tingting , Zhang Ao , Li Xiaoyu , Zhang Yongxin , Cen Shan 
Published: November 2024

ABSTRACT

Enterovirus-A71 (EV-A71) is the second most common causative agent after coxsackievirus A16 of hand, foot, and mouth disease. The capsids of EV-A71 consist of 60 copies of each of the four viral structural proteins (VP1–VP4). VP1 is highly exposed and surface accessible, playing a central role in virus particle assembly, attachment, and entry. To gain insight into the role of highly conserved residues at positions 75, 78, and 88 in the capsid protein VP1 in these processes, an alanine-scanning analysis was performed using an infectious cDNA clone of EV-A71. Our study revealed that the substitutions of VP1-T75A, VP1-T78A, and VP1-G88A could affect the assembly of the virus capsid proteins, resulting in the production of abnormal virions with reduced infectivity. Specifically, the substitution of VP1-T75A affected the maturation cleavage of the VP0 precursor, leading to deficiencies in binding to receptor scavenger receptor class B2 (SCARB2), viral attachment, internalization, and even uncoating. For the mutants of T78A and G88A, a significant reduction in virion-associated genomic RNA was observed, suggesting that more noninfectious empty particles were produced during viral assembly. Interestingly, the VP1-T75A variant showed weak replication in cell cultures but demonstrated increased virulence in BALB/c neonatal mice, which might be due to the difference in viral receptors among mammalian species. Taken together, our data revealed the important role of the highly conserved residues T75, T78, and G88 in VP1 protein in the infectivity of EV-A71. Characterizing these novel determinants of EV-A71 virulence would contribute to rationally developing effective treatments and broadly protective vaccine candidates.

IMPORTANCE
EV-A71 causes hand, foot, and mouth disease in children. In this study, we discovered three highly conserved residues at positions 75, 78, and 88 of the capsid protein VP1 as the potential virulence determinants of EV-A71, which can influence viral replication by regulating the assembly of EV-A71. Mechanistic studies revealed that VP1-T75A could affect the maturation cleavage of the VP0 precursor, resulting in deficiencies in binding to the receptor SCARB2, viral attachment, internalization, and even uncoating. For the mutants of T78A and G88A, more noninfectious empty particles were produced during viral assembly. The discovery of these novel determinants of EV-A71 virulence will promote the study of the pathogenesis of enteroviruses.