bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconceptualizing Generativity for a New Generation
Authors: Devies Brittany , Guthrie Kathy L.
Published: May 2024

Recently, the world has experienced multiple pandemics. During these multiple pandemics, including COVID‐19 and a racial reckoning in the United States, leadership has primarily looked like crisis management. As the world continues to evolve, with some looking to return to life as it looked pre‐pandemic and others defining new ways of being, leadership is also changing. As we collectively vision what comes next for generative leadership, it is essential to analyze the shift from crisis management and mere survival to more long‐term visioning and generative leadership practices. With this in mind, the following questions are asked: How do leaders reconceptualize generativity? How are leadership processes grounded in cultures of care, support, and critical hope? How are crisis management and post‐crisis leadership balanced in a world full of multiple complexities? The symposium seeks to explore these questions and more, looking to live in the complexity of reconceptualizing generativity for a new generation.
Presence of SARS‐CoV‐2 RNA in COVID‐19 survivors with post‐COVID symptoms 2 years after hospitalization: The VIPER study
Authors: Fernández‐de‐las‐Peñas César , Torres‐Macho Juan , Ruiz‐Ruigómez Maria , Arrieta‐Ortubay Estibaliz , Rodríguez‐Rebollo Carolina , Akasbi‐Moltalvo Míriam , Pardo‐Guimerá Virginia , Ryan‐Murua Pablo , Lumbreras‐Bermejo Carlos , Pellicer‐Valero Oscar J. , Giordano Rocco , Arendt‐Nielsen Lars , Franco‐Moreno Anabel
Published: May 2024

The SARS‐CoV‐2 VIrus PERsistence (VIPER) study investigated the presence of long‐lasting SARS‐CoV‐2 RNA in plasma, stool, urine, and nasopharyngeal samples in COVID‐19 survivors. The presence of SARS‐CoV‐2 RNA reverse transcription polymerase chain reactions (RT‐PCR) were analyzed within plasma, stool, urine, and nasopharyngeal swab samples in COVID‐19 survivors with post‐COVID symptoms and a comparison group of COVID‐19 survivors without post‐COVID symptoms matched by age, sex, body mass index and vaccination status. Participants self‐reported the presence of any post‐COVID symptom (defined as a symptom that started no later than 3 months after the initial infection). Fifty‐seven (57.9% women, age: 51.1, standard deviation [SD]: 10.4 years) previously hospitalized COVID‐19 survivors with post‐COVID symptoms and 55 (56.4% women, age: 50.0, SD: 12.8 years) matched individuals who had a past SARS‐CoV‐2 infection without post‐COVID symptoms were evaluated 27 (SD 7.5) and 26 (SD 8.7) months after hospital discharge, respectively. The presence of SARS‐CoV‐2 RNA was identified in three nasopharyngeal samples of patients with post‐COVID symptoms (5.2%) but not in plasma, stool, or urine samples. Thus, SARS‐CoV‐2 RNA was not identified in any sample of survivors without post‐COVID symptoms. The most prevalent post‐COVID symptoms consisted of fatigue (93%), dyspnea, and pain (both, 87.7%). This study did not find SARS‐CoV‐2 RNA in plasma, stool, or urine samples, 2 years after the infection. A prevalence of 5.2% of SARS‐CoV‐2 RNA in nasopharyngeal samples, suggesting a potential active or recent reinfection, was found in patients with post‐COVID symptoms. These results do not support the association between SARS‐CoV‐2 RNA in plasma, stool, urine, or nasopharyngeal swab samples and post‐COVID symptomatology in the recruited population.
Aerosol impacts on the East Asian winter monsoon: Insights from TaiESM1 and CMIP6 simulations
Authors: Tsai I‐Chun , Yang Szu‐Wei , Shiu Chein‐Jung , Chen Yi‐Ying , Chen Cheng‐An , Lee Wei‐Liang , Hsu Huang‐Hsiung
Published: May 2024

The East Asian winter monsoon (EAWM) is an important climate pattern in Southeast Asia. This study delved into the aerosol effects on the EAWM by analysing simulations conducted with the Taiwan Earth System Model version 1 (TaiESM1) model, part of the Coupled Model Intercomparison Project Phase 6 (CMIP6). Our assessment, validated against observational and reanalysis data, revealed that TaiESM1 effectively replicates the robust circulation of the EAWM and aerosol concentrations, placing its performance above average level among CMIP6 models. Notably, the simulated global mean aerosol optical thickness exhibited an approximately 20% increase from 1850 to 2014. The increased aerosols corresponded to a weakened Aleutian Low and an intensified Siberian High, leading to a weakened EAWM in the lower atmosphere over extratropical areas. In addition, the cooling across the Northern Hemisphere might affect enhanced northerly winds at approximately 10°N, which are situated in the southern part of the EAWM. An analysis of the near‐surface temperature budget indicated that the aerosol‐induced cooling in East China and India was primarily driven by changes in shortwave and longwave radiation fluxes, albeit slightly offset by sensible heat and latent heat fluxes. Furthermore, our study also reveals that while the mechanisms through which anthropogenic aerosols affect the northern portion of the EAWM vary across most CMIP6 models, their impacts on the tropical region remain consistent.
Necessity entrepreneurship: A journey from unemployment to self‐employment
Authors: Lim Weng Marc , Bansal Sanchita , Kumar Satish , Singh Shifali , Nangia Priya
Published: May 2024

This study provides a comprehensive examination of necessity entrepreneurship, a concept distinct from its counterpart, opportunity entrepreneurship. Necessity entrepreneurship emerges from the compelling need to address economic hardship or unemployment, contrasting with opportunity entrepreneurship, which is driven by the pursuit of new market opportunities. The backdrop of this study is anchored in the escalating unemployment crisis and its implications for sustainable economic growth and the attainment of sustainable development goals. Through an integrative review combining bibliometric–content analysis of 96 publications, following the PRISMA protocol, and a detailed case analysis of 10 globally recognized entrepreneurs who embarked on their ventures driven by necessity, this study unravels the critical factors fueling the rise of necessity entrepreneurship. The findings delineate the relationship between necessity and opportunity entrepreneurship, highlighting how an entrepreneurial orientation can serve as a pivotal link. This orientation not only mitigates the adverse effects of unemployment but also propels the economy toward sustainable growth, thereby contributing significantly to the sustainable development goals. The insights derived from this study traverse multiple domains including entrepreneurial orientation, socio‐economic factors, as well as innovation and digitalization, offering a granular perspective on business policy, entrepreneurial ecosystems, the disparate impacts on developed versus developing nations, and the role of innovation in dynamic entrepreneurship. Through a conceptual framework, this study elucidates how entrepreneurial orientation can effectively bridge the gap between the unemployment crisis and sustainable economic growth. Therefore, this study not only enriches the academic discourse on necessity entrepreneurship but also provides pragmatic insights for entrepreneurs, policymakers, and scholars, emphasizing the crucial role of entrepreneurship in navigating economic and social challenges.
Radiomic features of the medial meniscus predicts incident destabilizing meniscal tears: Data from the osteoarthritis initiative
Authors: Villagran Michelle , Driban Jeffrey B. , Lu Bing , MacKay James W. , McAlindon Timothy E. , Harkey Matthew S.
Published: May 2024

The objective of this study was to determine the optimal meniscal radiomic features to classify people who will develop an incident destabilizing medial meniscal tear. We used magnetic resonance (MR) images from an existing case–control study that includes images from the first 4 years of the Osteoarthritis Initiative (OAI). For this exploratory analysis (n = 215), we limited our study sample to people with (1) intact menisci at the OAI baseline visit, (2) 4‐year meniscal status data, and (3) complete meniscal data from each region of interest. Incident destabilizing meniscal tear was defined as progressing from an intact meniscus to a destabilizing tear by the 48‐month visit using intermediate‐weighted fat‐suppressed MR images. One reader manually segmented each participant's anterior and posterior horn of the medial menisci at the OAI baseline visit. Next, 61 different radiomic features were extracted from each medial meniscus horn. We performed a classification and regression tree (CART) analysis to determine the classification rules and important variables that predict incident destabilizing meniscal tear. The CART correctly classified 24 of the 34 cases and 172 out of 181 controls with a sensitivity of 70.6% and a specificity of 95.0%. The CART identified large zone high gray level emphasis (i.e., more coarse texture) from the posterior horn as the most important variable to classify who would develop an incident destabilizing medial meniscal tear. The use of radiomic features provides sensitive and quantitative measures of meniscal alterations, allowing us to intervene and prevent destabilizing meniscal tears.
High prevalence of gastrointestinal disorders in a large cohort of patients with joint hypermobility
Authors: Sood Vibha , Kaul Ajay , El‐Chammas Khalil I. , Mukkada Vincent A. , Sun Qin , Fei Lin , Santucci Neha R.
Published: May 2024

The gastrointestinal (GI) manifestations in children with hypermobile Ehlers–Danlos syndrome/joint hypermobility syndrome (hEDS/JHS) are not well described. We investigated the prevalence of GI disorders in children and young adults with hEDS/JHS through a single‐center retrospective review. Demographic data, clinical history, symptoms, and diagnostic studies were reviewed. Of 435 patients with hEDS/JHS, 66% were females (age 5−28 years). We noted a high prevalence of constipation (61%), dysphagia (32%), dyspepsia and/or gastroparesis (25%), eosinophilic esophagitis (EoE) (21%), and celiac disease (4%) in our cohort. Upper endoscopy and gastric emptying scans had the highest yield to detect abnormalities. Motility studies were abnormal in 31% of the 80 patients who underwent them. Dysphagia symptoms are significantly associated with EoE. Thirty‐three percent of dysphagia patients had EoE, versus 16% of non‐dysphagia patients (p < 0.001). Screening hEDS/JHS patients for GI issues should be routine, with further investigations and referrals guided by identified symptoms.
A phenomenological study of tourists' categories in the Indian Himalayan Region
Authors: Chandra Pramod
Published: May 2024

Tourists visiting the Indian Himalayan Region are categorized from an etic perspective; consequently, they are considered akin to the nature and congruity of the regional destinations. However, evidence indicates that an aberration has occurred in the region's tourism activities, adversely influencing the host communities' cultural and social context. From an emic perspective, this paper presents a new categorization of visiting tourists in the region. This research took a phenomenological stance, and 34 in‐depth interviews were conducted to collect the primary data. Subsequently, a thematic analysis was performed to analyze data. Findings demonstrate that, due to an aberration in the form of tourists, the cultural and social order of the region is experiencing antithetical issues, and host communities are becoming skeptical about the sector's existing tourism model and revenue aspirations; therefore, conflicts are intensifying between tourism development and revenue aspirations in the region. The study concludes by proposing future research directions.
A comparative analysis of surgically excised hereditary and sporadic pheochromocytomas: Insights from a single‐center experience
Authors: Nasiroglu Imga Narin , Deniz Muzaffer Serdar , Tural Balsak Belma Ozlem , Aslan Yilmaz , Tuncel Altug , Berker Dilek
Published: May 2024

Pheochromocytoma is a tumor that usually originating from adrenal medullary chromaffin cells and producing one or more catecholamines, can manifest as hereditary or sporadic. While the majority pheochromocytomas are sporadic, hereditary forms are often associated with genetic syndromes such as von Hippel–Lindau, multiple endocrine neoplasia type 2, and neurofibromatosis type 1. This study aims to analyze data from our series of surgically excited pheochromocytoma patients and compare the characteristics between hereditary and sporadic cases. We retrospectively evaluated 33 diagnosed pheochromocytoma patients, documenting clinical features, surgical complications, and tumor characteristics in both hereditary and sporadic cases. Among the patients, 21% (7 individuals) had hereditary pheochromocytoma, while 79% (26 individuals) had sporadic cases. During diagnosis, hereditary pheochromocytoma patients exhibited a significantly lower mean age compared to the sporadic group (26.4 ± 9.9 years vs. 50.4 ± 14.0 years; p < 0.001). The maximum tumor size was also lower in hereditary cases compared to sporadic cases (p = 0.004). Adrenal tumor localization analysis showed that 63.6% were right‐sided, 24.2% were left‐sided, and 12.1% were bilateral. Laboratory analysis revealed significantly higher urinary norepinephrine levels in hereditary pheochromocytoma patients (p = 0.021). Our findings suggest that hereditary pheochromocytoma cases are characterized by a younger age at diagnosis, smaller tumor size, and a higher prevalence of multiple bilateral adrenal adenomas. We recommend genetic testing for all pheochromocytoma patients, particularly those with early‐onset disease and bilateral adrenal tumors.
Movement Disorders in Patients with Subacute Sclerosing Panencephalitis: A Systematic Review
Authors: Garg Divyani , Patel Sahil , Sankhla Charulata S. , Holla Vikram V. , Paramanandam Vijayashankar , Kukkle Prashanth L. , Pandey Sanjay , Schneider Susanne A. , Pal Pramod K.
Published: May 2024

Background

Subacute sclerosing panencephalitis (SSPE) is a complication of measles, occurring after a latency of 4–10 years. It continues to occur in developing countries although resurgence is being reported from developed countries. Characteristic features include progressive neuropsychiatric issues, myoclonus, seizures, movement disorders and visual impairment. Electroencephalography (EEG) typically shows periodic generalized discharges, and elevated CSF anti‐measles antibodies are diagnostic. Movement disorders are being increasingly recognized as part of the clinical spectrum, and range from hyperkinetic (chorea, dystonia, tremor, tics) to hypokinetic (parkinsonism) disorders and ataxia.

Objectives

This article aims to comprehensively review the spectrum of movement disorders associated with SSPE.

Methods

A literature search was conducted in PubMed and EMBASE databases in December 2023 and articles were identified for review.

Results

Movement disorders reported in SSPE included hyperkinetic (chorea, dystonia, tremor and tics), hypokinetic (parkinsonism), ataxia and extraocular movement disorders. Myoclonus, a core clinical feature, was the most frequent “abnormal movement.” Movement disorders were observed in all clinical stages, and could also be a presenting feature, even sans myoclonus. Hyperkinetic movement disorders were more common than hypokinetic movement disorders. An evolution of movement disorders was observed, with ataxia, chorea and dystonia occurring earlier, and parkinsonism later in the disease. Neuroradiological correlates of movement disorders remained unclear.

Conclusion

A wide spectrum of movement disorders was observed throughout the clinical stages of SSPE. Most data were derived from case reports and small case series. Multicentric longitudinal studies are required to better delineate the spectrum and evolution of movement disorders in SSPE.
Understanding Anxiety in Cervical Dystonia: An Imaging Study
Authors: Mahajan Abhimanyu , Stoub Travis , Gonzalez David A. , Stebbins Glenn , Gray Gabrielle , Warner‐Rosen Tila , Sugar Dana , Pylypyuk Caroline , Yu Mandy , Comella Cynthia
Published: May 2024

Background

Anxiety may precede motor symptoms in cervical dystonia (CD) and is associated with an earlier onset of dystonia. Our understanding of anxiety in CD is inadequate.

Objective

To investigate brain networks associated with anxiety in CD.

Methods

Twenty‐six subjects with idiopathic CD underwent MRI Brain without contrast. Correlational tractography was derived using Diffusion MRI connectometry. Quantitative Anisotropy (QA) was used in deterministic diffusion fiber tracking. Correlational tractography was then used to correlate QA with State–Trait Anxiety Inventory (STAI) state (STAI‐S) and trait (STAI‐T) subscales.

Results

Connectometry analysis showed direct correlation between state anxiety and QA in tracts from amygdala to thalamus/ pulvinar bilaterally, and trait anxiety and QA in tracts from amygdala to motor cortex, sensorimotor cortex and parietal association area bilaterally (FDR ≤0.05).

Conclusion

Our efforts to map anxiety to brain networks in CD highlight the role of the amygdala in the pathophysiology of anxiety in CD.
Sequential free fibula transfers: Quality of life and systematic review
Authors: Wu Robin T. , Lin Jennifer An‐Jou , Su Chun‐Lin , Wei Fu‐Chan
Published: May 2024

Background

Successive osteoseptocutaneous fibula transfers for jaws reconstruction are rare but important options. This study contributes patient‐reported and clinical outcomes, as well as systematically reviews all existing reports.

Methods

All sequential fibula transfers performed by the senior author were reviewed from a prospectively managed database, including University of Washington quality of life (UWQoL). Systematic review was conducted in PubMed and Cochrane databases for similar publications.

Results

Eighteen patients (average age 51.5 years) received sequential fibulas (mean 4.7 years between reconstructions). Secondary fibulas more often had benign indications (72.2% vs. 33.3%, p = .04), most commonly osteoradionecrosis (38.9%). At a mean follow‐up of 30.5 months, the average interincisal distance increased from 21.8 to 27.6 mm, and 92.3% tolerated an oral diet following the second fibula.

Eight patients completed the UW‐QoL before and after the second fibula, and three prior to the first fibula. Composite physical function was significantly decreased from 96.7 prefibula reconstruction to 63.3 following the first (p < .001) and 64.2 after the second fibula (p < .001). There were no differences in other domains.

The systematic review yielded six articles reporting 56 patients (mean 39 months between fibulas). Secondary fibulas were performed for repeat malignancy (45%) and osteoreadionecrosis (39%), resulting in elevated tube feeding from 20% following the first to 39% following the second, but overall high quality of life in two studies.

Conclusions

Sequential osteoseptocutaneous fibula reconstructions of jaws are often performed for benign indications such as osteoradionecrosis. Overall function and QoL are comparable with those following the first fibula transfer.
The soliton and periodic solutions for the perturbed sine–cosine–Gordon equation
Authors: Yang Deniu
Published: May 2024

In the paper, the existence of soliton and periodic solutions is studied for the perturbed sine–cosine–Gordon equation. The corresponding traveling wave system is converted to a regularly Hamilton system via using bifurcation theory of differential equations and the geometric singular perturbation theory. Then by using Melnikov's method and symbolic computation, periodic wave solutions, solitary solutions, and kink and antikink solutions are obtained. The wave speed selection principles are given, respectively. Numerical simulations are performed to illustrate our theoretical analysis.
Fixed points of multivalued contractions in Hausdorff controlled metric spaces with applications
Authors: Phiangsungnoen Supak
Published: May 2024

In this article, we introduce two multivalued contractive mappings within the framework of Hausdorff controlled metric spaces, employing concepts of admissibility and
‐class functions. The first mapping is a
‐generalized contractive multivalued mapping, and the second is a
‐multivalued mapping. We establish conditions guaranteeing the existence of fixed points for these mappings. To support our theoretical findings, we provide a numerical example, demonstrating the independence of the contractive conditions for the mappings. Furthermore, we apply our results to a specific problem in polynomial equations. These findings complement several existing results in the literature.
On the distributional fractional derivative: From unidimensional to multidimensional
Authors: Saadi Abderachid
Published: May 2024

In this paper, we use the generalized notions of Riemann–Liouville (fractional calculus with respect to a regular function) to extend the definitions of fractional integration and derivative from the functional sense to the distributional sense. First, we give some properties of fractional integral and derivative for the functions infinitely differentiable with compact support. Then, we define the weak derivative, as well as the integral and derivative of a distribution with compact support, and the integral and derivative of a distribution using the convolution product. Then, we generalize those concepts from the unidimensional to the multidimensional case. Finally, we propose the definitions of some usual differential operators.
Whole‐cerebrum guanidino and amide CEST mapping at 3 T by a 3D stack‐of‐spirals gradient echo acquisition
Authors: Wang Kexin , Ju Licheng , Song Yulu , Blair Lindsay , Xie Kevin , Liu Claire , Li Anna M , Zhu Dan , Xu Feng , Liu Guanshu , Heo Hye‐Young , Yadav Nirbhay Narayan , Oeltzschner Georg , Edden Richard A. E. , Qin Qin , Kamson David Olayinka , Xu Jiadi
Published: May 2024

Purpose

To develop a 3D, high‐sensitivity CEST mapping technique based on the 3D stack‐of‐spirals (SOS) gradient echo readout, the proposed approach was compared with conventional acquisition techniques and evaluated for its efficacy in concurrently mapping of guanidino (Guan) and amide CEST in human brain at 3 T, leveraging the polynomial Lorentzian line‐shape fitting (PLOF) method.

Methods

Saturation time and recovery delay were optimized to achieve maximum CEST time efficiency. The 3DSOS method was compared with segmented 3D EPI (3DEPI), turbo spin echo, and gradient‐ and spin‐echo techniques. Image quality, temporal SNR (tSNR), and test–retest reliability were assessed. Maps of Guan and amide CEST derived from 3DSOS were demonstrated on a low‐grade glioma patient.

Results

The optimized recovery delay/saturation time was determined to be 1.4/2 s for Guan and amide CEST. In addition to nearly doubling the slice number, the gradient echo techniques also outperformed spin echo sequences in tSNR: 3DEPI (193.8 ± 6.6), 3DSOS (173.9 ± 5.6), and GRASE (141.0 ± 2.7). 3DSOS, compared with 3DEPI, demonstrated comparable GuanCEST signal in gray matter (GM) (3DSOS: [2.14%–2.59%] vs. 3DEPI: [2.15%–2.61%]), and white matter (WM) (3DSOS: [1.49%–2.11%] vs. 3DEPI: [1.64%–2.09%]). 3DSOS also achieves significantly higher amideCEST in both GM (3DSOS: [2.29%–3.00%] vs. 3DEPI: [2.06%–2.92%]) and WM (3DSOS: [2.23%–2.66%] vs. 3DEPI: [1.95%–2.57%]). 3DSOS outperforms 3DEPI in terms of scan–rescan reliability (correlation coefficient: 3DSOS: 0.58–0.96 vs. 3DEPI: −0.02 to 0.75) and robustness to motion as well.

Conclusion

The 3DSOS CEST technique shows promise for whole‐cerebrum CEST imaging, offering uniform contrast and robustness against motion artifacts.
Finite element modeling of thermal‐hydro‐mechanical coupled processes in unsaturated freezing soils considering air‐water capillary pressure and cryosuction
Authors: Norouzi Emad , Li Biao
Published: May 2024

This paper presents a comprehensive computational model for analyzing thermo‐hydro‐mechanical coupled processes in unsaturated porous media under frost actions. The model employs the finite element method to simulate multiphase fluid flows, heat transfer, phase change, and deformation behaviors. A new soil freezing characteristic curve model is proposed to consider the suctions from air‐water capillary pressure and water‐ice cryosuction. A total pore pressure with components from liquid water pressure, air pressure, and ice pressure is used in the effective stress law. Vapor and dry air are considered miscible gases, utilizing the ideal gas law and Dalton's law. The governing equations encompass the linear momentum balance equation, the energy balance equation, and mass conservation equations for water species (ice, liquid, and vapor) and dry air. Weak forms are formulated based on primary variables of displacement, water pressure, air pressure, and temperature. The spatial discretization is achieved through the finite element method, while temporal discretization employs the fully implicit finite difference method, resulting in a system of fully coupled nonlinear equations. To verify the proposed computational model, a numerical implementation is developed and validated against a set of experimental data from the literature. The successful verification demonstrates the robustness of the model. A detailed discussion of the contributions from phase change strain and different sources of pore pressure is also addressed.
The shadow of institutional racism on people of color's involvement in membership associations
Authors: AbouAssi Khaldoun , Berlan David , Wright James
Published: May 2024

Membership associations are membership owned; they serve their members but play a critical role in the society. This study examines association membership and volunteering behaviors to identify differences in how people of color experience these organizations. Results detect continued barriers to engagement by people of color in terms of volunteering opportunities, and less so for joining these associations. People of color tend to engage in more activities but dedicate less time to these engagements, creating unbalanced results; yet they find more satisfaction from these engagements compared to their White counterparts. Associations themselves must continue to identify and remove barriers to fair participation rooted in racism.
Characterization of discordance between mismatch repair deficiency and microsatellite instability testing may prevent inappropriate treatment with immunotherapy
Authors: Geurts Birgit S , Zeverijn Laurien J , van Berge Henegouwen Jade M , van der Wijngaart Hanneke , Hoes Louisa R , de Wit Gijs F , Spiekman Ilse AC , Battaglia Thomas W , van Beek Daphne M , Roepman Paul , Jansen Anne ML , de Leng Wendy WJ , Broeks Annegien , Labots Mariette , van Herpen Carla ML , Gelderblom Hans , Verheul Henk MW , Snaebjornsson Petur , Voest Emile E
Published: May 2024

In the Drug Rediscovery Protocol (DRUP), patients with cancer are treated based on their tumor molecular profile with approved targeted and immunotherapies outside the labeled indication. Importantly, patients undergo a tumor biopsy for whole‐genome sequencing (WGS) which allows for a WGS‐based evaluation of routine diagnostics. Notably, we observed that not all biopsies of patients with dMMR/MSI‐positive tumors as determined by routine diagnostics were classified as microsatellite‐unstable by subsequent WGS. Therefore, we aimed to evaluate the discordance rate between routine dMMR/MSI diagnostics and WGS and to further characterize discordant cases. We assessed patients enrolled in DRUP with dMMR/MSI‐positive tumors identified by routine diagnostics, who were treated with immune checkpoint blockade (ICB) and for whom WGS data were available. Patient and tumor characteristics, study treatment outcomes, and material from routine care were retrieved from the patient medical records and via Palga (the Dutch Pathology Registry), and were compared with WGS results. Initially, discordance between routine dMMR/MSI diagnostics and WGS was observed in 13 patients (13/121; 11%). The majority of these patients did not benefit from ICB (11/13; 85%). After further characterization, we found that in six patients (5%) discordance was caused by dMMR tumors that did not harbor an MSI molecular phenotype by WGS. In six patients (5%), discordance was false due to the presence of multiple primary tumors (n = 3, 2%) and misdiagnosis of dMMR status by immunohistochemistry (n = 3, 2%). In one patient (1%), the exact underlying cause of discordance could not be identified. Thus, in this group of patients limited to those initially diagnosed with dMMR/MSI tumors by current routine diagnostics, the true assay‐based discordance rate between routine dMMR/MSI‐positive diagnostics and WGS was 5%. To prevent inappropriate ICB treatment, clinicians and pathologists should be aware of the risk of multiple primary tumors and the limitations of different tests. © 2024 The Pathological Society of Great Britain and Ireland.
Catalytic cyanate resin with polysulfide cation catalyst and its ultra‐high molecular weight polyethylene fiber composites for radome
Authors: Jiang Jingyu , Geng Hongbo , Xu Ke , Wang Hao , Zhou Yijia , Guo Xu , Zhang Chunhua
Published: May 2024

Cyanate (CE) resin and ultrahigh‐molecular‐weight polyethylene (UHMWPE) fiber are respectively important matrix and reinforcing material for lightweight and high wave‐transparent composites. However, the preparation and application of the composites is limited by the mismatch of molding temperature between CE resin and UHMWPE fiber. The best method to solve this problem is to catalyze the CE resin curing reaction and reduce its molding temperature from 270 to 135°C, which is the upper heat‐resistance temperature of UHMWPE fiber. In this study, the polysulfide catalyst (PSC) was used to catalyze CE resin curing reaction, reduce the curing reaction activation energy and the molding temperature. The apparent activation energy of the CE‐PSC resin decreases from 107.2 to 60.7 kJ mol−1, and the glass transition temperature of the CE‐PSC resin is 257.2°C, flexural strength and tensile strength are 120.2 and 60.8 MPa, respectively. As a result, the CE‐PSC/UHMWPE fiber composites, which are molded at the matching temperature of 135°C, have low density of 1.05 g cm−3, low dielectric constant of 2.4, low dielectric loss of 0.006, and high wave transmittance of 92.2%. Therefore, the CE‐PSC/UHMWPE fiber composites have wide application prospect in the field of light weight and high wave‐transparent composites.

Highlights

A novel catalytic CE resin can be cured at 135°C with low dielectric properties.

The processing temperature mismatch between CE and UHMWPE fiber was solved.

Catalytic CE/UHMWPE composites have lightweight and high wave‐transparent properties.
Printability and mechanical properties of solution impregnated continuous jute yarn reinforced acrylonitrile butadiene styrene composites fabricated by fused deposition modeling
Authors: Razavi‐Nouri Mohammad , Afsharkohan Mohammad Saleh , Rezadoust Amir Masood , Zaredar Zahra
Published: May 2024

This work aimed to check the influence of solution impregnated (SIP) jute yarn on printability and mechanical properties of 3D printed continuous jute yarn reinforced biocomposites. Acrylonitrile butadiene styrene (ABS) was employed as the matrix and the biocomposites were fabricated by in‐nozzle melt impregnation fused deposition modeling (FDM). The thermoplasic polyurethane (TPU), polystyrene (PS) and ABS solutions with the concentration of 2 and 10 wt% were prepared for making the SIP jute yarn. The best tensile strength and pull‐out results were obtained for the single strand composed of ABS and jute in which the yarn was impregnated with the solution containing 2 wt% TPU (TPU2%) before processing. The three printing parameters of layer height, print speed and nozzle diameter were changed to compare the process window of the composite specimens fabricated using the solution unimpregnated (SUIP) and SIP jute yarn with TPU2%. The results indicated that the print speed could be higher for the SIP one than that of its counterpart. The tensile and short beam shear tests of the non‐dried (ABS/NDJ) and dried ABS/Jute (ABS/DJ) composites revealed that the influence of drying was more obvious on the tensile properties results than those of on the short beam shear test. In addition, the yield stress, elastic modulus and tensile strength of ABS/DJ were 24, 17 and 12% higher than for ABS/NDJ, respectively. However, the highest tensile properties and short beam shear test results were acquired for the composites fabricated by jute yarn SIP with TPU2%.

Highlights

Printability of ABS/impregnated continuous jute yarn composites was studied by FDM

TPU, PS and ABS of 2 and 10 wt% solutions were used to impregnate the jute yarn

Three printing parameters were altered to find the process window for FDM process

Best mechanical properties was obtained for ABS/Jute filament impregnated by TPU2%

Process window was wider for the impregnated than that for unimpregnated composite
Tensile and compressive properties of bamboo scrimber under different temperature conditions
Authors: Deng Jie , Wei Yang , Chen Si , Chen Jiawei , Zhao Kang , Li Guofen
Published: May 2024

Bamboo scrimber demonstrates vulnerability to environmental temperature fluctuations, such as exposure to cold or fire, when deployed in structural applications. Consequently, its mechanical properties can substantially diverge from the intended design values under varying thermal conditions. This study aims to study the tensile and compressive properties of bamboo scrimber under different temperatures to provide data support for studying bamboo scrimber under low and high temperatures. The compressive properties of bamboo scrimber under temperatures ranging from −30°C to 250°C and the tensile properties under −20°C to 250°C were determined by a series of tests with a total of 125 specimens. The results show that the mass loss of bamboo scrimber increases gradually with the increase in temperature, and the increasing trend intensifies after 120°C. With the increase of temperature, the failure mode of the specimens under compression changes from the bottom compression cracking damage to the local destabilization of longitudinal fibers, while the tensile damage modes aren't influenced by temperature, and both “straight‐line” and “folded‐line” types of damage modes occur at different temperatures. The tensile and compressive strengths and elastic modulus of the specimens decreased with the increase in temperature, and the strength was more susceptible to the temperature than the elastic modulus: a rise in temperature from 20°C to 250°C resulted in a reduction of compressive strength and tensile strength by 80.80% and 84.11%, respectively, the compressive modulus and tensile modulus experienced decreases of 49.51% and 53.28%. Furthermore, equations of temperature influence coefficients of strength and elastic modulus were established based on the test results.

Highlights

Bamboo scrimber's mechanical properties under different temperatures are studied.

Tendency and explanation of temperature influence coefficients are analyzed.

Temperature coefficient equations for strength and elastic modulus are proposed.
Experimental characterization and numerical prediction for mechanical aging of epoxy and its carbon fiber‐reinforced composite under hydrothermal conditions
Authors: Zhang Wanrui , Liu Meiyu , Zou Jianchao , Han Zhibin , Xiong Yifeng , Liang Biao , Zhang Weizhao
Published: May 2024

The Aqueous environment impairs the mechanical performance of carbon fiber‐reinforced polymers (CFRPs) and decreases the durability of engineering structures made of CFRPs primarily by degrading the resin matrix. Hence, the objective of this study is to investigate and accurately predict the influence of hydrothermal aging on the epoxy and its carbon fiber reinforced polymer (CFRP). Particularly, this work developed a modeling method that combined Fick's model, empirical aging model and elastoplastic constitutive model to predict the mechanical behavior of hydrothermally aged epoxy matrix. After the experimental characterization, this epoxy modeling method demonstrated its predictive capability on the mechanical response of the deteriorated epoxy under different hydro‐thermal‐salt conditions, with the mean absolute percent error (MAPE) of approximately 4.61%. Furthermore, the transverse compressive behavior of unidirectional (UD) CFRPs could be predicted by using the representative volume element (RVE) model with the degraded matrix behavior predicted via this epoxy modeling method. Integrated with this CFRP modeling, results from mechanical tests and fracture analysis further demonstrated that the hydrothermal aging effect on the transverse compressive performance of the UD CFRPs was dominated by the deterioration of their resin matrix. Therefore, this study demonstrates the feasibility of the finite element analysis (FEA) for mechanical aging of the epoxy matrix and its CFRP under hydrothermal conditions via employing the proposed integrated modeling method.

Highlights

Degradation of epoxy polymer under hydro‐thermal‐salt aging conditions.

Integrated model to predict mechanical response of hydrothermally aged epoxy.

RVE model to predict the mechanical behavior of hydrothermally aged CFRP.

Hydrothermal aging on the transverse compressive behavior of UD CFRP.
Quantitative detection of aging damage of solid propellant based on frequency impedance spectroscopy combined with CARS‐SVM algorithm
Authors: Duan Leiguang , Wang Xueren , Zhang Binbin , Qiang Hongfu
Published: May 2024

Solid propellant, as the energy source for solid rocket engines, it is of great significance to achieve accurate quantitative detection of aging damage of solid propellant. In this paper, a novel approach based on frequency impedance spectroscopy impedance combined with CARS‐SVM algorithm was proposed. First, the temperature, humidity, and pressure of environmental information around the solid rocket motor were sampled, and then the impedance at corresponding frequencies of the propellant was obtained by AD5933 chip. Second, the processed experimental data were subjected to abnormal sample detection before further variables selection using uninformative variables elimination (UVE) competitive adaptive reweighted sampling (CARS), respectively. Finally, support vector machine (SVM), UVE‐SVM and CARS‐SVM quantitative calibration methods were established. The results showed that the determination coefficient (R2), root mean square error (RMSE), and mean absolute percentage error (MAPE) of CARS‐SVM model were 0.9919, 0.7540, and 0.0480, respectively. Therefore, the results prove that impedance of solid propellant combined with CARS‐SVM model can effectively achieve high precision quantitative detection of aging damage of solid propellant, which lays a new method for the application of solid propellants aging damage in the online quantitative detection.
A numerical determination of complex solid gun propellant burn rates through closed bomb simulation
Authors: Houthuysen Christopher , Parziale Nicholaus
Published: May 2024

Closed bomb testing is a prominent means of characterizing the combustion behavior of solid gun propellants. This sub‐scale test allows the propellant to burn in a constant volume environment, where the resulting pressure‐time trace can be collected via a pressure transducer. Historically, numerical procedures have been developed to determine the burn rates of the gun propellants from these pressure‐time traces; however, no standardized procedure exists to determine the burn rates of grains with variable surface thermochemistry and ignition criteria. To address this capability gap, a non‐linearly constrained, multivariate optimization algorithm has been developed to decouple propellant grain surfaces and determine surface‐specific burn rates [1]. In this work, the optimization algorithm as well as the legacy Excel‐based Closed Bomb (XLCB) program [2] were used to determine the burn rates of homogeneous, deterred, and layered propellants from experimental data. Closed bomb simulations using these burn rates were then conducted with the two‐phase, multidimensional, interior ballistics solver, iBallistix [3]. The maximum mean error between the simulated and experimental pressure‐time curves was 6.8 % for the optimization algorithm and 23.8 % for XLCB, showing a marked improvement with our new approach. Furthermore, the approach discussed herein improves burn rate predictions of complex solid gun propellants when compared with legacy closed bomb data reduction analysis programs.
Hydroxyl‐terminated polybutadiene(HTPB) propellants cross‐linked by dimer acid diisocyanate (DDI): Cross‐linking network and properties
Authors: Xin Kai , Yang Rongjie , Yang Kairui , Li Jianmin , Zhai Jinxian
Published: May 2024

Considering the high toxicity of toluene diisocyanate (TDI) and the low reactivity of isophorone diisocyanate (IPDI), a low‐toxicity curing agent, dimer acid diisocyanate (DDI), was used to cross‐link HTPB elastomers and propellants. The unique long‐chain structure of DDI not only ensures the elastic modulus and tensile strength of the elastomer, but also improves the flexibility to some extent. The long flexible chains promote the segment movement, which is very important for the formation of hydrogen bonds between segments. The chemical cross‐linking network and hydrogen bonding association play a significant role in the mechanical properties of the HTPB/DDI system. The relationship between the mole ratio of ‐NCO to ‐OH (R‐value) and the mechanical properties of HTPB/DDI elastomers were also investigated. In the range of R‐value from 0.85 to 1.2, the elastic modulus and tensile strength first increase and then decrease, and the elongation at break first decreases and then increases. Under the same curing conditions, the elastic modulus and tensile strength of the HTPB/DDI propellant are similar to the HTPB/TDI propellant. For the HTPB/AP/Al propellants and HTPB/AP/RDX/Al propellants, the HTPB/DDI system has lower burning rates in the range of 5–19 MPa than the HTPB/TDI system and HTPB/IPDI system. The application of DDI can reduce the burning rates of the propellant without adding any burning rate modifiers. It is considered that DDI can replace TDI and IPDI as a new curing agent with low toxicity and moderate reactivity for HTPB systems.
Analysis of thermomechanical coupled accelerated aging of HTPB propellants
Authors: Zeng Yi , Huang Wei , Chen Jia‐Xing , Xu Jin‐Sheng , Chen Xiong , Wu Rui , Song Qi‐Xuan
Published: May 2024

This study employed macroscopic uniaxial compression tests at low and medium strain rates, coupled with microscopic electron microscopy, to extensively analyse the impact of thermomechanical coupled aging on the accelerated aging of Hydroxyl‐terminated Polybutadiene (HTPB) propellants, contrasting it with the effects of isolated factors such as heat and dynamic reciprocating force. Results indicate that at various environmental temperatures (323 K, 343 K, and 363 K), thermomechanical coupled aging more significantly affects HTPB propellants than isolated factors. This effect is macroscopically evident in increased ease of deformation, permanent deformation during aging, continual increase in dissipated energy, and a decrease in average stress and ultimate strain post‐aging. Microscopically, the effect predominantly arises from the interplay between matrix thermal degradation and particle fragmentation, which rapidly accumulate and substantially impact the material's macroscopic mechanical properties. Furthermore, as the aging temperature rises, the alterations in both macroscopic mechanical properties and microscopic morphology of HTPB propellants become more pronounced. However, overly high temperatures may swiftly result in substantial material performance deterioration. Consequently, while elevating temperature effectively accelerates thermomechanical aging, the potential adverse effects on material performance must be judiciously considered. This underscores the necessity of balancing temperature regulation with aging efficiency enhancement in HTPB propellants to ensure effective control and quantitative assessment of the aging process, while minimizing material degradation.
Characterization of the interaction between the Sec61 translocon complex and ppαF using optical tweezers
Authors: Robeson Luka , Casanova‐Morales Nathalie , Burgos‐Bravo Francesca , Alfaro‐Valdés Hilda M. , Lesch Robert , Ramírez‐Álvarez Carolina , Valdivia‐Delgado Mauricio , Vega Marcela , Matute Ricardo A. , Schekman Randy , Wilson Christian A. M.
Published: May 2024

The Sec61 translocon allows the translocation of secretory preproteins from the cytosol to the endoplasmic reticulum lumen during polypeptide biosynthesis. These proteins possess an N‐terminal signal peptide (SP) which docks at the translocon. SP mutations can abolish translocation and cause diseases, suggesting an essential role for this SP/Sec61 interaction. However, a detailed biophysical characterization of this binding is still missing. Here, optical tweezers force spectroscopy was used to characterize the kinetic parameters of the dissociation process between Sec61 and the SP of prepro‐alpha‐factor. The unbinding parameters including off‐rate constant and distance to the transition state were obtained by fitting rupture force data to Dudko–Hummer–Szabo models. Interestingly, the translocation inhibitor mycolactone increases the off‐rate and accelerates the SP/Sec61 dissociation, while also weakening the interaction. Whereas the translocation deficient mutant containing a single point mutation in the SP abolished the specificity of the SP/Sec61 binding, resulting in an unstable interaction. In conclusion, we characterize quantitatively the dissociation process between the signal peptide and the translocon, and how the unbinding parameters are modified by a translocation inhibitor.
Engineering G protein‐coupled receptors for stabilization
Authors: Velloso João Paulo L. , de Sá Alex G. C. , Pires Douglas E. V. , Ascher David B.
Published: May 2024

G protein‐coupled receptors (GPCRs) are one of the most important families of targets for drug discovery. One of the limiting steps in the study of GPCRs has been their stability, with significant and time‐consuming protein engineering often used to stabilize GPCRs for structural characterization and drug screening. Unfortunately, computational methods developed using globular soluble proteins have translated poorly to the rational engineering of GPCRs. To fill this gap, we propose GPCR‐tm, a novel and personalized structurally driven web‐based machine learning tool to study the impacts of mutations on GPCR stability. We show that GPCR‐tm performs as well as or better than alternative methods, and that it can accurately rank the stability changes of a wide range of mutations occurring in various types of class A GPCRs. GPCR‐tm achieved Pearson's correlation coefficients of 0.74 and 0.46 on 10‐fold cross‐validation and blind test sets, respectively. We observed that the (structural) graph‐based signatures were the most important set of features for predicting destabilizing mutations, which points out that these signatures properly describe the changes in the environment where the mutations occur. More specifically, GPCR‐tm was able to accurately rank mutations based on their effect on protein stability, guiding their rational stabilization. GPCR‐tm is available through a user‐friendly web server at https://biosig.lab.uq.edu.au/gpcr_tm/.