bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Digital Competence on Nurses’ Career Sustainability: A Cross‐Sectional Study
Authors: Zhang Zeyu , Zhao Shuang , Shao Yujiao , Duan Xiaocui , Sun Ping , Chen Lingling , Wang Fei , Yuan Changjiang , Yang Xiumu
Published: November 2024

Aim: This study aimed to elucidate the relationship between digital competence (DC), nurses’ career sustainability (CS), and the moderating role of family‐supportive supervisory behavior.

Background: Nurses’ CS is crucial in promoting medical digital transformation in China. Thus, clarifying the influencing factors of nurses’ CS has become a priority.

Methods: This cross‐sectional investigation was carried out in Anhui Province, China. Eight hundred and fifty‐four nurses received self‐administered questionnaires, which included the Digital Competence Questionnaire, Career Self‐Efficacy Scale, Career Sustainability Scale, and Family‐Supportive Supervisory Behavior Scale. A hierarchical regression analysis was used to test a hypothesized model.

Results: Nurses’ CS is significantly predicted by DC (r = 0.52, p < 0.01), and career self‐efficacy (CSE) mediates this association (β = 0.682, p < 0.01). In addition, family‐supportive supervisor behavior (FSSB) moderates the relationship between DC and CSE (β = 0.146, p < 0.01).

Conclusions: Our study investigates the positive impact of DC on nurses’ CS at both the individual and organizational levels, identifies potential boundary conditions, and advances theoretical research on nurses’ CS while providing a solid foundation for developing effective strategies to improve nurses’ CS.

Implications for Nursing Management: Hospital managers and leaders should focus on organizational support for nurses and their families, formulate intervention measures to increase nurses’ DC and CSE, and improve their CS.
Supplementary Methods from Deconvoluting Mechanisms of Acquired Resistance to RAF Inhibitors in BRAFV600E-Mutant Human Glioma
Authors: Schreck Karisa C. , Morin Andrew , Zhao Guisheng , Allen Amy N. , Flannery Patrick , Glantz Michael , Green Adam L. , Jones Chris , Jones Kenneth L. , Kilburn Lindsay B. , Nazemi Kellie J. , Samuel David , Sanford Bridget , Solomon David A. , Wang Jiawan , Pratilas Christine A. , Nicolaides Theodore , Mulcahy Levy Jean M.
Published: November 2024

Supplementary Methods
Supplemental Table 2 from Deconvoluting Mechanisms of Acquired Resistance to RAF Inhibitors in BRAFV600E-Mutant Human Glioma
Authors: Schreck Karisa C. , Morin Andrew , Zhao Guisheng , Allen Amy N. , Flannery Patrick , Glantz Michael , Green Adam L. , Jones Chris , Jones Kenneth L. , Kilburn Lindsay B. , Nazemi Kellie J. , Samuel David , Sanford Bridget , Solomon David A. , Wang Jiawan , Pratilas Christine A. , Nicolaides Theodore , Mulcahy Levy Jean M.
Published: November 2024

GSEA analysis of paired RNA samples. Samples were analyzed using both the C2 (Curated Gene Sets) and C6 (Oncogenic Signature Gene Sets) MSigDB Collections. Comparisons were made either between the pre- and post-BRAFi samples within the TGFB1-high (Group 1) (tabs Group_1_c2, Group_1_c6) or TGFB1-low (Group 2) (tabs Group_2_c2, Group_2_c6) clusters, and between the post-BRAFi samples (tabs Group_1_vs_2_post-treatment_c2, Group_1_vs_2_post-treatment_c6). We additionally compared all samples without clustering pre- and post-BRAFi (tabs All_pre_vs_post_c2, All_pre_vs_post_c6).
Supplementary Figure 2 from IL13Rα2 Promotes Proliferation and Outgrowth of Breast Cancer Brain Metastases
Authors: Márquez-Ortiz R. Alejandro , Contreras-Zárate Maria J. , Tesic Vesna , Alvarez-Eraso Karen L.F. , Kwak Gina , Littrell Zachary , Costello James C. , Sreekanth Varsha , Ormond D. Ryan , Karam Sana D. , Kabos Peter , Cittelly Diana M.
Published: November 2024

Supplementary Figure 2. Global RNA sequencing was performed in doxycycline-induced 231BR EV vs 231BR shIL13RA2 cells 48 h after DOXY-induction (n=3/group). Ingenuity® Pathway Analysis (IPA®). The p-value (calculated with the Fischer's exact) and Z-score were determined to stablish any probable association between our set of genes and a function. Migration and replication biofunctions are predicted as being activated and repressed, respectively, when IL13Rα2 is downregulated with a high absolute Z-score ({greater than or equal to}2) and a significant p-value (<0.05).
Supplementary Data from The MAGNOLIA Trial: Zanubrutinib, a Next-Generation Bruton Tyrosine Kinase Inhibitor, Demonstrates Safety and Efficacy in Relapsed/Refractory Marginal Zone Lymphoma
Authors: Opat Stephen , Tedeschi Alessandra , Linton Kim , McKay Pamela , Hu Bei , Chan Henry , Jin Jie , Sobieraj-Teague Magdalena , Zinzani Pier Luigi , Coleman Morton , Thieblemont Catherine , Browett Peter , Ke Xiaoyan , Sun Mingyuan , Marcus Robert , Portell Craig A. , Ardeshna Kirit , Bijou Fontanet , Walker Patricia , Hawkes Eliza A. , Mapp Sally , Ho Shir-Jing , Talaulikar Dipti , Zhou Ke-Shu , Co Melannie , Li Xiaotong , Zhou Wenxiao , Cappellini Massimo , Tankersley Chris , Huang Jane , Trotman Judith
Published: November 2024

Supplement
Supplementary Data from Diagnostic Accuracy of FEC-PET/CT, FDG-PET/CT, and Diffusion-Weighted MRI in Detection of Nodal Metastases in Surgically Treated Endometrial and Cervical Carcinoma
Authors: Rockall Andrea G. , Barwick Tara D. , Wilson William , Singh Naveena , Bharwani Nishat , Sohaib Aslam , Nobbenhuis Marielle , Warbey Victoria , Miquel Marc , Koh Dow-Mu , De Paepe Katja N. , Martin-Hirsch Pierre , Ghaem-Maghami Sadaf , Fotopoulou Christina , Stringfellow Helen , Sundar Sudha , Manchanda Ranjit , Sahdev Anju , Hackshaw Allan , Cook Gary J. , Stewart Victoria , Farthing Alan , Kyrgiou Maria , Yazbek Joseph , Dina Roberto , Ind Thomas , Barton Desmond , Butler John , Attygalle Ayoma , Hazell Steve , Taylor Alexandra , Lalondrelle Susan , Zerizer Imene , Rosof-Williams Diana , Dobson Mike , Hill Jonathan , Brockbank Elly , Lawrence Alexandra , Jeyarajah Arjun , Oram David , Ganesan Raji , Guest Peter , Davies Mark , Vosper Laura , Coetzee Carike
Published: November 2024

Supplementary data
Supplementary Table S4 from St. Jude Survivorship Portal: Sharing and Analyzing Large Clinical and Genomic Datasets from Pediatric Cancer Survivors
Authors: Matt Gavriel Y. , Sioson Edgar , Shelton Kyla , Wang Jian , Lu Congyu , Zaldivar Peraza Airen , Gangwani Karishma , Paul Robin , Reilly Colleen , Acić Aleksandar , Liu Qi , Sandor Stephanie R. , McLeod Clay , Patel Jaimin , Wang Fan , Im Cindy , Wang Zhaoming , Sapkota Yadav , Wilson Carmen L. , Bhakta Nickhill , Ness Kirsten K. , Armstrong Gregory T. , Hudson Melissa M. , Robison Leslie L. , Zhang Jinghui , Yasui Yutaka , Zhou Xin
Published: November 2024

Associations of haplotypes with cardiomyopathy
Supplementary Figure S8 from St. Jude Survivorship Portal: Sharing and Analyzing Large Clinical and Genomic Datasets from Pediatric Cancer Survivors
Authors: Matt Gavriel Y. , Sioson Edgar , Shelton Kyla , Wang Jian , Lu Congyu , Zaldivar Peraza Airen , Gangwani Karishma , Paul Robin , Reilly Colleen , Acić Aleksandar , Liu Qi , Sandor Stephanie R. , McLeod Clay , Patel Jaimin , Wang Fan , Im Cindy , Wang Zhaoming , Sapkota Yadav , Wilson Carmen L. , Bhakta Nickhill , Ness Kirsten K. , Armstrong Gregory T. , Hudson Melissa M. , Robison Leslie L. , Zhang Jinghui , Yasui Yutaka , Zhou Xin
Published: November 2024

Exporting data for haplotype analysis
Novel index based on inflammatory markers correlates with treatment efficacy of nivolumab for recurrent/metastatic head and neck cancer
Authors: Tada Hiroe , Kawabata-Iwakawa Reika , Takahashi Hideyuki , Chikamatsu Kazuaki
Published: November 2024

Introduction: Immune checkpoint inhibitors provide new treatments for patients with recurrent or metastatic (R/M) head and neck cancers. Herein, we focused on systemic inflammatory markers in peripheral blood, including blood cell fractions, albumin, and C-reactive protein, and determined their association with nivolumab treatment response. We also examined the potential application of inflammatory markers as prognostic tools.
Methods: We assessed pre-treatment systemic inflammatory markers in 61 patients with R/M head and neck cancer treated with nivolumab, determining their association with treatment response using Kaplan–Meier, multivariate, and regression analyses. Using flow cytometry, we investigated circulating T cell subsets in 36 patients with R/M head and neck cancer. Finally, we examined the correlation between each statistically analyzed parameter and peripheral circulating T cell activation.
Results: Systemic inflammatory marker values were used to estimate overall survival time by performing multivariate analysis. Systemic inflammatory markers were assigned importance for each coefficient. Monocyte and lymphocyte counts strongly impacted overall survival. Indices dependent on white blood cell and monocyte counts, lymphocyte percentage, platelet count, albumin levels, and prognostic nutrition index were useful prognostic tools in the regression analysis. The simplest prognostic index was defined as white blood cells (103/μL) +2×lymphocyte percentage (%) +12×number of monocytes (103/μL)+27×serum albumin. A high index that was significantly associated with a better prognosis negatively correlated with CD38/CD8 and ki67/CD8 percentages.
Conclusions: According to the findings of the present study, systemic inflammatory markers may help predict the prognosis, activation, and exhaustion of circulating T cells. In patients with R/M head and neck cancer treated with nivolumab, systemic inflammatory markers could provide new insights into rational strategies in cancer immunotherapy for R/M head and neck cancer.
Rescue Stenting for Failed Mechanical Thrombectomy in Acute Basilar Artery Occlusions: Analysis of the PC-SEARCH Registry
Authors: Ortega-Gutierrez Santiago , Rodriguez-Calienes Aaron , Mierzwa Adam T. , Galecio-Castillo Milagros , Dibas Mahmoud , Al Kasab Sami , Nelson Ashley , Jadhav Ashutosh P. , Desai Shashvat , Toth Gabor , Alrohimi Anas , Abdalkader Mohamad , Klein Piers , Nguyen Thanh N. , Salahuddin Hisham , Pandey Aditya , Koduri Sravanthi , Vora Niraj , Aladamat Nameer , Gharaibeh Khaled , Afreen Ehad , Zaidi Syed , Jumaa Mouhammad
Published: November 2024

BACKGROUND:

We aimed to investigate whether rescue stenting (RS) following failed mechanical thrombectomy (MT) for acute basilar artery occlusion results in superior functional outcomes and enhanced safety compared with the natural history of failed MT.

METHODS:

This retrospective cohort study utilized data from the Posterior Circulation Ischemic Stroke Evaluation: Analyzing Radiographic and Intra-Procedural Predictors for Mechanical Thrombectomy registry, encompassing 8 high-volume centers in the United States and covering the period from 2015 to 2021. Patients with basilar artery occlusion who experienced failed MT (modified Thrombolysis in Cerebral Infarction score of 0–2a after at least 1 attempt of clot retrieval) were categorized based on whether they received additional intervention with RS. The primary outcome was a shift analysis of the 90-day modified Rankin Scale. Multivariable logistic regression was used to assess both efficacy and safety outcomes.

RESULTS:

Of a total of 444 patients, 119 presented failed MT and were included in the analysis. The RS group comprised 65 (14.6%) patients, while the control group consisted of 54 (12.2%) patients. After adjusting, the RS group showed a favorable shift in the overall 90-day modified Rankin Scale distribution (adjusted common odds ratio, 4.56 [95% CI, 1.67–12.45];
P
=0.003) and higher rates of 90-day 0 to 3 modified Rankin Scale score (RS: 44.6% versus control: 18.5%; adjusted odds ratio, 7.57 [95% CI, 1.91–30.12];
P
=0.004) compared with the control group. RS also showed lower rates of 90-day mortality (RS: 43.1% versus control: 64.8%; adjusted odds ratio, 0.27 [95% CI, 0.09–0.80];
P
=0.018) and comparable rates of symptomatic intracranial hemorrhage (RS: 3.1% versus control: 13%; adjusted odds ratio, 0.31 [95% CI, 0.05–1.95];
P
=0.214).

CONCLUSIONS:

Our study demonstrated that RS is associated with improved functional outcomes and reduced mortality in basilar artery occlusion patients presenting MT failure. Further randomized trials are needed to validate these findings.
Globalization, Immigrant-Origin Students & the Quest for Educational Equity
Authors: Suárez-Orozco Carola , Suárez-Orozco Marcelo
Published: November 2024

Globalization has come to define the modern world. Originally venerated as a force that would bring humanity to the peak of its flourishing through economic integration and positive cross-cultural exchange, globalization has deepened economic inequities, driven the dangerous degradation of the environment, and destabilized regions over fights for resources. Migration, a natural response to this precarity, has swelled, making the children of immigrants a growing, key demographic in schools across many high- and middle-income countries. The resilience, flexible thinking, and multilingualism of immigrant-origin students make them valuable community members in our globalized world. However, their schools are not always equipped to meet their psychosocial needs. While the current primary focus on language acquisition is an important foundation for supporting these students, an equitable whole-child approach is necessary to address their unique challenges and create an environment in which they can flourish.
Migration & the Quest for Educational Equity in Germany
Authors: Georgi Viola B.
Published: November 2024

Germany has undergone a significant transformation from a nation that saw itself as culturally homogeneous to a society characterized by diversity and immigration. The education system, however, continues to struggle to meet the needs of children and young people from diverse backgrounds. This manifests in forms of unequal treatment and discrimination that impede the effective integration and education of students from different ethnic, linguistic, cultural, and religious groups. This is particularly true for students from nonacademic, low-socioeconomic status backgrounds, as well as for students from immigrant families: categories that frequently overlap. However, there are promising educational interventions and initiatives that address issues of democracy, diversity, and equal opportunity in schools. I provide an overview of select issues in the production and reproduction of inequality in the German school system and in everyday teaching practices, with a focus on including students of immigrant origin.
Multicultural Education in Nigeria
Authors: Obiakor Festus E.
Published: November 2024

Nigeria is the most populous Black nation in the world and richest nation in Africa. It has multiple tribes, cultures, languages, religions, and values. It gained its independence from British colonial rule on October 1, 1960. Even with independence, colonialism has had aftereffects that have exacerbated sociocultural maladies such as tribalism, religious fanaticism, massive corruption, military coups, and devastating conflicts (like the 1967-1970 Biafra-Nigeria War, which took millions of lives). While education is a powerful tool in socioeconomic and political developments, it has not been philosophically changed to respond to the cultural, linguistic, and religious diversities of Nigeria's citizenry. Can an adequate educational foundation be instituted without valuing the multicultural strengths of Nigeria? Can Nigeria's progress be advanced without paradigm and power shifts in the education of all students? Can Nigerians 'freedoms be equalized without respect for all tribes? Nigeria must foster multicultural education to advance itself at all levels.
Disrupted Institutional Pathways for Educational Equity in Conflict-Affected Nations
Authors: Akar Bassel
Published: November 2024

Areas and systems affected by compounded crises, protracted conflicts, and structural violence often struggle to reform education for social reconstruction. At the forefront, we observe tireless and ambitious ventures among donor agencies, government institutions, and international and local organizations. However, in many of these cases, we also witness deepening political gridlock, stagnation, and marginalization that undermine the progress of an empowering education for citizenship that upholds principles of human rights. Causal factors to these institutional failures are often either overlooked, redacted, or undocumented in research. Evidence from Morocco, Iraqi Kurdistan, and, most of all, Lebanon illustrates the extent to which governance systems in education can either hinder or even prevent equity in education.
Predicting Human Translation Difficulty with Neural Machine Translation
Authors: Lim Zheng Wei , Vylomova Ekaterina , Kemp Charles , Cohn Trevor
Published: November 2024

Human translators linger on some words and phrases more than others, and predicting this variation is a step towards explaining the underlying cognitive processes. Using data from the CRITT Translation Process Research Database, we evaluate the extent to which surprisal and attentional features derived from a Neural Machine Translation (NMT) model account for reading and production times of human translators. We find that surprisal and attention are complementary predictors of translation difficulty, and that surprisal derived from a NMT model is the single most successful predictor of production duration. Our analyses draw on data from hundreds of translators operating across 13 language pairs, and represent the most comprehensive investigation of human translation difficulty to date.
Peng Chun Chang and the Justification for Human Rights in East Asia
Authors: O’Dwyer Shaun
Published: November 2024

This paper reviews recent scholarship on P.C. (Peng Chun) Chang’s pivotal roles as a Confucian and diplomat in the drafting of the 1948 Universal Declaration of Human Rights to argue that he articulated a pioneering Confucian justification for human rights, distinctive from then-influential Western, Christian justifications. However, it also argues that theorizing the human rights advocacy of mid-20th-century Confucians like Chang does not suffice on its own to advance the compatibilist case for Confucianism and human rights, especially when it is recalled how Chang’s advocacy was forgotten. Relative to the influential human rights advocacy of East Asian churches, Confucianism also suffers from a reputational deficit in East Asian human rights thought due to its lack of civic visibility and its negative associations with developmental authoritarianisms in East Asia. The paper concludes that Confucians aiming for a more authoritative Confucian advocacy of human rights must also acknowledge and confront this reputational deficit.
2. Interests
Authors: Weatherson Brian
Published: November 2024

This chapter sets out the primary argument that knowledge is interest-relative. It describes a simple kind of game, and argues that orthodox philosophical approaches to knowledge are committed to judging clearly irrational ways to play the game to be rational. It also sets out more carefully just what the interest-relative view is, and what the orthodox view it seeks to overturn is, as well as describe two other alternatives (to both interest-relativity and orthodoxy) that should be considered.
5. Inquiry
Authors: Weatherson Brian
Published: November 2024

On the theory of this book, if something is known, it is available to use as a starting point in inquiry. It is natural to move from that view to the view that it is irrational to inquire into what one already knows. But recent work on inquiry shows that this isn’t right; depending on what one wants to do in an inquiry one may want to deliberately set aside some things one knows. And that might mean inquiry into what one already knows, what we ordinarily call double-checking, is reasonable. This fact is used to respond to an influential objection by Jessica Brown to the style of argument I use in chapter 2.
Urological Cancers in Douala (Cameroon): Epidemiological and Histological Profile
Authors: Guy Epoupa , Stéphane Nwaha , Oriol Mbouché , Quentin Essomba , Nkeng Glenda , Aristide Soppo , Paterson Atangana , Hervé Moby , Joseph Fouda
Published: November 2024

Background: According to Globocan 2020, the global burden of cancer has increased to 19.3 million cases and 10 million cancer deaths. The International Agency for Research on Cancer estimates that, in the world, one in five people develop cancer during their lifetime. Urinary tract cancers are common in urology. They are most often of a bad prognosis. While the epidemiology of urological cancers is well known in the Northern Countries, data on these conditions are little available or insufficient. The purpose of this study was to determine the frequency of urological cancers, describe their clinical presentation and classification. Methodology: We conducted a transversal study in the urology, oncology and pathology anatomy departments of the Douala General Hospital (DGH) and the Douala Laquintinie Hospital (DLH). Medical records and pathology reports of biopsies carried out on patients with urological cancer and hospitalized over a period of 10 years from January 1, 2010 to December 31, 2019 were included. Results: A total of 93 cases were selected. The sex ratio of 8:1. The average age was 64.7±11.51 years for men and 45.8±23 years for women (p=0.030). Smoking was the main comorbidity (30.1%). Low back pain, hematuria and urine retention were the main modes of revelation. Prostate cancer was found in 75.3%. Prostate adenocarcinoma was the most found histological type (94.1%) Kidney, bladder and penis cancer were found in 16.1%; 7.5% and 1% of cases. More than half of patients with prostate cancer (68.6%) had metastasis at the time of diagnosis. Conclusion: urological cancers affect men more. The symptomatology is dominated by the signs of the upper and lower urinary tract. Prostate adenocarcinoma is the most found histological type.
Alterations in the biorheological features of some soft tissues after limb lengthening
Authors: Huang Kun , Zeng Yanjun , Xia Hetao , Liu Changgui
Published: November 2024

The aim of this study was to investigate the effects of a surgical limb lengthening procedure on the biorheological features of some lengthened soft tissues. In this procedure external fixators were applied to goats’ right radius to stretch the tissues. The right forelegs of goats were lengthened by 2, 4 cm, respectively. After lengthening ceased, the goats were examined after different periods of time. The lengthened median nerves, arteries and veins were harvested and used to study their biorheological features. Tensile strength of lengthened and control specimens were measured and their stress relaxation features and stress‐strain relationships were studied. Results showed that at the beginning of recovery, the stress‐strain curves, relaxation curves and tensile strengths of the lengthened specimens began to deviate from those of their controls. However, with increasing recovery time, the curves and tensile strength of the lengthened specimens reverted to those of their controls. All the tissues studied exhibited the same behavior.
On the viscoelastic character of liver tissue: experiments and modelling of the linear behaviour
Authors: Liu Zizhen , Bilston Lynne
Published: November 2024

This paper presents the results of recent investigations into the viscoelastic character of liver tissue, especially the linear response. The linear domain of liver tissue has been determined by a strain sweep oscillation test. The fluid‐like viscoelastic behaviour of liver tissue was confirmed by stress relaxation experiments. To demonstrate the consistency and quality of the experimental data, the relaxation spectrum was used to reconstruct the relaxation modulus, as well as the storage and loss moduli. The generalised Maxwell model was successfully employed to model the mechanical behaviour in the linear viscoelastic domain.
Inhibition of polymer‐induced red blood cell aggregation by poloxamer 188
Authors: Toth K. , Wenby R.B. , Meiselman H.J.
Published: November 2024

Previous reports have suggested that non‐ionic poloxamer surfactants of appropriate molecular mass and composition can reduce red blood cell (RBC) aggregation in whole blood and in RBC‐plasma suspensions. We have thus evaluated this phenomenon for RBC aggregated by several water‐soluble polymers, using poloxamer 188 (P188), a non‐ionic, tri‐block molecule (total molecular mass of 8.40 kDa, 80% polyoxyethylene). Human RBC were washed, then re‐suspended in isotonic solutions of dextran 70 (70.3 kDa), dextran 500 (476 kDa), PVP (360 kDa) or P‐L‐GLU (61.2 kDa); density‐separated RBC were also studied. RBC aggregation was quantitated via a computerized Myrenne Aggregometer (extent, strength) and by the Microscopic Aggregation Index (MAI) method. Over the range of 0.5 to 5 mg/ml, poloxamer 188 inhibited both the extent and strength of aggregation in a dose‐dependent manner, with the magnitude of the decrease related to polymer type (e.g., at 5 mg/ml, 62% decrease for dextran 70 vs. 14% decrease for P‐L‐GLU); MAI results with dextran 70 also showed a dose‐dependent decrease. Poloxamer 188 at 5 mg/ml was more effective with younger, less‐dense cells. Based upon the depletion model for polymer‐induced aggregation, these findings suggest that poloxamer 188 acts by penetrating the depletion layer near the glycocalyx, thereby reducing the osmotic gradient between the intercellular gap and the suspending medium. Regardless of the specific mechanism(s) of action, poloxamers appear to offer interesting approaches for future basic science and clinical studies, and thus the possibility for greater insight into RBC aggregation.
Flow around cells adhered to a microvessel wall. I. Fluid stresses and forces acting on the cells
Authors: Sugihara‐Seki Masako
Published: November 2024

To evaluate the fluid forces acting on cells adhered to a microvessel wall, we numerically studied the flow field around adherent cells and the distribution of the stresses on their surfaces. For simplicity, the cells were modeled as rigid particles attached to a wall of a circular cylindrical tube regularly in the flow direction, in a row or two rows. It was found that not the detailed shape of the model cells but their height from the vessel wall is a key determinant of the fluid forces and torque acting on them. In both arrangements of one row and two rows, the axial spacing between neighboring adherent cells significantly affects the distributions of the stresses on them, which results in drastic variations of the fluid forces with the axial spacing and the relative positions with respect to their neighboring cells. The drag force acting on an adherent cell in the vessel was evaluated to be larger than the value in the 2D chamber flow at the same wall shear stress, mainly due to much larger variations of the pressure distribution on the cell surface in the vessel flow.
Aggregation behavior and electrophoretic mobility of red blood cells in various mammalian species
Authors: Baskurt Oguz K. , Bor‐Kucukatay Melek , Yalcin Ozlem , Meiselman Herbert J.
Published: November 2024

Differences of red blood cell (RBC) aggregation among various mammalian species has been previously reported for whole blood, for RBC in autologous plasma, and for washed RBC re‐suspended in polymer solutions. The latter observation implies the role of cellular factors, yet comparative studies of such factors are relatively limited. The present study thus investigated RBC aggregation and RBC electrophoretic mobility (EPM) for guinea pigs, rabbits, rats, humans and horses; RBC were re‐suspended in isotonic 500 kDa dextran solutions for the EPM and aggregation measurements, with aggregation studies also done in autologous plasma. Salient results included: (1) species‐specific RBC aggregation in both plasma and dextran (horse > human > rat > rabbit ≅ guinea pig) with a significant correlation between aggregation in the two media; (2) similar EPM values in PBS for rat, human and horse, a lower value for guinea pig, and a markedly reduced EPM for rabbit RBC; (3) EPM values in dextran with a rank order identical to that for cells in PBS; (4) relative EPM results indicating formation of a polymer‐poor, low viscosity depletion layer at the RBC surface (greatest depletion for horse RBC). EPM‐aggregation correlations were evident and generally consistent with the Depletion Model for aggregation, yet did not fully explain differences between species; additional studies at various ionic strengths and with various dextran fractions thus seem warranted.
Visualization of flow‐dependent concentration polarization of macromolecules at the surface of a cultured endothelial cell monolayer by means of fluorescence microscopy
Authors: Naiki Takeru , Karino Takeshi
Published: November 2024

To substantiate the occurrence of flow‐dependent concentration or depletion of atherogenic lipoproteins, which has been theoretically predicted to take place at a blood/endothelium boundary, we have studied the effects of perfusion pressure and wall shear rate on the accumulation and uptake of microspheres by cultured vascular endothelial cells in a monolayer. The study was carried out by flowing a cell culture medium containing fetal calf serum and fluorescent microspheres through a parallel‐plate flow chamber having a cultured bovine aortic endothelial cell (BAEC) monolayer on one wall of the chamber. The microspheres had a nominal diameter of 19 nm, approximately the same as that of low‐density lipoproteins, and thus served as models and tracers of plasma proteins and lipoproteins. Experiments were carried out in steady flow in the physiological range of wall shear rate and water filtration velocity at the monolayer, while monitoring the intensity of fluorescence of the spheres accumulated at and taken up by the endothelial cells. It was found that in a perfusate containing only fluorescent microspheres, due to increased phagocytic activity of the endothelial cells, the intensity of fluorescence which reflected the number of the microspheres taken up by the endothelial cells, increased almost linearly with time and independently of wall shear rate. However, with perfusates containing fetal calf serum, this abnormal phenomenon did not occur, and the intensity of fluorescence increased with increasing perfusion pressure and decreasing wall shear rate. It was also found that the number of fluorescent microspheres accumulated at and taken up by the BAEC monolayer was shear‐dependent only at low wall shear rates, and increased sharply when the flow rate was reduced to zero. These results provided solid experimental evidence that flow‐dependent concentration or depletion of macromolecules occurs at the luminal surface of the endothelium at physiological wall shear rates and water filtration velocities, and strongly supports the hypothesis that flow‐dependent concentration polarization of lipoproteins plays an important role in the localization of atherosclerosis and intimal hyperplasia in man by facilitating the uptake of atherogenic lipoproteins by endothelial cells.
The “black hole” phenomenon in ultrasonic backscattering measurement under pulsatile flow with porcine whole blood in a rigid tube
Authors: Cao Pei‐Jie , Paeng Dong‐Guk , Shung K.K.
Published: November 2024

The “black hole” phenomenon was further investigated with porcine whole blood under pulsatile flow conditions in a straight rigid tube 120 cm long and of 0.95 cm diameter. A modified Aloka 280 commercial scanner with a 7.5 MHz linear array was used to collect the radio frequency (RF) signal of backscattering echoes from the blood inside the tube. The transducer was located downstream from the entrance and parallel to the longitudinal direction of the tube. The experimental results showed that higher hematocrits enhanced the black hole phenomenon, leading to a more apparent and larger diameter black hole. The black hole was not apparent at hematocrits below 23%. The highest hematocrit used in the experiment was 60%. Beat rates of 20, 40 and 60 beats per minute (bpm) were used, and the black hole became weaker in amplitude and smaller in diameter when the peak flow velocity was increased at each beat rate. These results are consistent with the suggestion in previous work that the black hole arises from insufficient aggregation of red blood cells (RBCs) at the center of the tube because of the low shear rate. At 20 and 40 bpm, the peak flow velocity ranges were 10∼25 cm/s and 18∼27 cm/s, respectively. The black hole was very clear at the minimal peak flow velocity but almost disappeared at the maximal velocities for each beat rate. At 60 bpm, experiments were only performed at one peak flow velocity of 31 cm/s and the black hole was clear. The results showed that the black hole was more pronounced at higher beat rates when the peak velocity was the same. This phenomenon cannot be explained by previous hypotheses. Acceleration seems to be the only flow parameter that varies at different beat rates when peak velocities are the same. Therefore, the influence of acceleration on the structural organization and orientation of RBC rouleaux might be another factor involved in the formation of the black hole in addition to the shear rate. As the entrance length was changed from 110 to 15 diameters (D) in seven steps at the hematocrit of 60%, it was found that a position farther downstream yielded a black hole with a greater contrast relative to the surrounding region, while the backscattering power at the central hypoechoic zone did not increase with increasing entrance length.
Alterations in the adhesion behavior of osteoblasts by titanium particle loading: Inhibition of cell function and gene expression
Authors: Kwon Soon Yong , Lin Tong , Takei Hiroshi , Ma Qingjin , Wood Douglas J. , O'Connor Daniel , Sung K.‐L. Paul
Published: November 2024

Total joint replacement prostheses are required to withstand corrosive environments and sustain millions of loading and articulation cycles during their term of implantation. Wear debris generation has been implicated as one of the primary causes of periprosthetic osteolysis and subsequent implant loosening in total joint replacements. Particulate debris consisting of metals, polyethylene, ceramics, and bone cement have each been shown to provoke a biological response in joint tissues. The major cell types within the interfacial granulomatous fibrous tissues consist of fibroblasts, macrophages, lymphocytes, and foreign‐body giant cells. Osteoblasts are one of the principal cell types in the bone tissue adjacent to prostheses, maintaining physiologic bone remodeling through the balanced coordination of bone formation and resorption in concert with osteoclasts. To date the phenomenon of osteoblast phagocytosis of titanium particles has been suggested, but has not been sufficiently studied or confirmed. This study seeks to clarify the influence of titanium particles on osteoblast adhesion, deformability, proliferation, and gene expression profile. These studies were accomplished by performing biorheological testing, Northern blot analysis and RNase protection assay. The uptake of metallic particles by the osteoblast resulted in a particle–filament complex formation, which induced a series of variations in cell function. Understanding these variations is critical to expanding our knowledge of implant loosening and elucidating the nature of prosthetic joint failure. This study suggests that the impact of titanium particles on osteoblast function and subsequent implant loosening may have been previously underestimated.
Theoretical and experimental analysis of the sedimentation kinetics of concentrated red cell suspensions in a centrifugal field: Determination of the aggregation and deformation of RBC by flux density and viscosity functions
Authors: Lerche Dietmar , Frömer Dirk
Published: November 2024

The flow properties of blood are mostly determined using various viscometric approaches, and described in terms of a shear rate or shear stress dependent apparent viscosity. The interpretation of results are rather difficult, especially at low shear rates when particle sedimentation and migration within the viscometer gap are significant. By contrast, analysing the separation process in concentrated RBC suspensions in a centrifugal field also yields information about the viscosity function, including particle–particle interaction and deformation parameters. In this paper, the sedimentation process is approached by means of the theory of kinematic waves and theoretically described by solving the corresponding one‐dimensional quasi‐linear partial differential equation based on viscosity/flow function as a function of volume concentration. The sedimentation kinetics of rigid spherical RBC suspended in saline and normal RBC suspended in Dx‐saline solutions were investigated by means of a separation analyser (LUMiFuge 114). The instrument detects the light transmission over the total length of the cell containing the suspension. During centrifugation the analyser automatically determines the position of the particle free fluid/suspension interface or the sediment by mans of a special algorithm. The data obtained with sedimentation of rigid spherical RBC at different volume concentrations demonstrate that, in the case of suspensions rotated in containers of constant cross section, there is good agreement between the theory of kinematic waves developed by Anestis and Schneider (1983) and the results of the experiments. Such good agreement was obtained even though a restrictive one‐dimensional model was used to obtain the theoretically derived sedimentation time course. In addition, we describe an algorithm enabling the experimental determination of the viscosity and related flux density function to be made for any suspension. Through this approach, we investigated in detail the rheological behavior of suspended rigid spheres at low Reynolds numbers ranging from 10−6 to 10−3. The method here introduced also enabled us to investigate RBC suspensions with respect to the deformability and interactions of the cells by means of the separation analysis. Normal, rigid as well as aggregating RBC exhibited marked differences in the sedimentation kinetics, which were quantified by means of the flux and viscosity functions based on the theory of kinematic waves.
A theoretical model for the elastic properties of very soft tissues
Authors: Secomb T.W. , El‐Kareh A.W.
Published: November 2024

A theoretical model is developed to predict the elastic properties of very soft tissues such as glands, tumors and brain. Tissues are represented as regular arrays of polyhedral (cubic or tetrakaidecahedral) cells, surrounded by extracellular spaces of uniform width. Cells are assumed to be incompressible, with very low resistance to shear deformation. Tissue shear rigidity is assumed to result mainly from the extracellular matrix, which is treated as a compressible elastic mesh of interconnected fibers. Small‐strain elastic properties of tissue are predicted using a finite‐element method and an analytical method. The model can be used to estimate the compressibility of a very soft tissue based on its Young's modulus and extracellular volume fraction.
The thixotropic effect of the synovial fluid in squeeze‐film lubrication of the human hip joint
Authors: Hlaváček M.
Published: November 2024

The thixotropic (shear‐thinning) effect of the synovial fluid in squeeze‐film lubrication of the human hip joint is evaluated, taking into account filtration of the squeezed synovial film by biphasic articular cartilage. A porous, homogeneous, elastic cartilage matrix filled with the interstitial ideal fluid, with the intact superficial zone (of lower permeability and stiffness in compression) already disrupted or worn away, models an early stage of arthritis. Due to a high viscosity of the normal synovial fluid at very low shear rates, the squeezed synovial film at a fixed time after the application of a steady load is found to be much thicker in a small central part of the lubricated contact area. In the remaining part, the film is thin as it corresponds to the Newtonian fluid with the same high‐shear‐rate viscosity. Filtration is lower for the normal cartilage with the intact superficial zone due to its lower permeability and compression stiffness. But even in the fictitious case of zero filtration, calculations show that the effect of thixotropy on the increase of the minimum synovial film thickness would manifest itself as late as after several tens of seconds since the physiologic load application. At that time, this thickness would be as low as about 0.3 μm. It follows that thixotropy of the normal synovial fluid (and so much more of the inflammatory fluid) is irrelevant in squeeze‐film lubrication of both the normal and arthritic human hip joints.
Rheology of hyaluronan solutions under extensional flow
Authors: Mo Yunqian , Nishinari Katsuyoshi
Published: November 2024

The extensional viscosity and the steady shear viscosity of sodium type hyaluronan (NaHA) in water with sodium chloride and/or sucrose and in DMSO solvent were measured. The extensional viscosities for HA in aqueous solution (0.05, 0.1, 0.3 w/v%) were constant at lower extensional rates, and then became strain thinning above a critical extensional rate. However, on adding sodium chloride, the extensional viscosity decreased and became strain thickening at higher extensional rates. Sodium ions shield the electrostatic repulsion between carboxyl residues of HA molecules and constrict the coil dimensions. The strain thickening of HA solution in the presence of sodium chloride at higher extension rates is due to the coil stretching. The addition of sucrose increased the extensional viscosity and shifted the critical extensional rate to lower strain rates. With increasing strain (shear) rates, extensional (shear) viscosities for HA aqueous solutions remained constant up to a critical extension (shear) rate; but they showed no plateau and decreased linearly in DMSO. It is clear that molecular interaction of HA in DMSO is stronger than that in aqueous solution. This should be attributed to the different conformations of HA in DMSO and in aqueous solutions.
Cell cytoskeleton and tensegrity
Authors: Volokh K.Yu. , Vilnay O. , Belsky M.
Published: November 2024

The role of tensegrity architecture of the cytoskeleton in the mechanical behavior of living cells is examined by computational studies. Plane and spatial tensegrity models of the cytoskeleton are considered as well as their non‐tensegrity counterparts. Local buckling including deep postbuckling response of the compressed microtubules of the cytoskeleton is considered. The tensioned microfilaments cannot sustain compression. Large deformation of the whole model is accounted and fully nonlinear analysis is performed. It is shown that in the case of local buckling of the microtubules non‐tensegrity models exhibit qualitatively the same linear stiffening as their tensegrity counterparts. This result raises the question of experimental validation of the local buckling of microtubules. If the microtubules of real cells are not straight, then tensegrity (in a narrow sense) is not a necessary attribute of the cytoskeleton architecture. If the microtubules are straight then tensegrity is more likely to be the cytoskeletal architecture.
Deformation properties of articular chondrocytes: A critique of three separate techniques
Authors: Bader D.L. , Ohashi T. , Knight M.M. , Lee D.A. , Sato M.
Published: November 2024

This paper presents a series of techniques, which examine the deformation characteristics of bovine articular chondrocytes. The direct contact approach employs well established methodology, involving AFM and micropipette aspiration, to yield structural properties of local regions of isolated chondrocytes. The former technique yields a non‐linear response with increased structural stiffness in a central location on a projected image of the chondrocyte. A simple viscoelastic model can be used with data from the micropipette aspiration technique to yield a mean value of Young's modulus, which is similar to that recently reported (Jones et al., 1999). An indirect approach is also described, involving the response of chondrocytes seeded within compressed agarose constructs. For 1% agarose constructs, the resulting cell strain, yields a gross cell modulus of 2.7 kPa. The study highlights the difficulties in establishing unique mechanical parameters, which reflect the deformation behaviour of articular chondrocytes.
Factors influencing the nonuniform localization of monocytes in the arterial wall
Authors: Truskey George A. , Barber Kevin M. , Rinker Kristina D.
Published: November 2024

Adhesion of monocytes to arterial endothelium may contribute to the asymmetric distribution of atherosclerotic lesions. Possible mechanisms for adhesion in the relatively high shear stress environment found in arteries include greater monocyte deformation and/or more frequent penetration of microvilli through steric and charge barriers. In vivo, secondary flows generate forces acting normal to the endothelial cell surface. These forces may cause compression of the microvilli or enable cells to overcome steric or electrostatic barriers, increasing adhesion. To investigate this, we examined monocyte adhesion to activated endothelium in recirculating flow. Adhesion was characterized by short arrests in a narrow region on either side of the reattachment line. The median arrest time was longer than that observed at comparable shear stresses in a linear shear flow. The lifetimes of adhesion were analyzed using a model for multiple bond formation. For cells adhering near the reattachment line, the bond number per cell was greater than the value found for similar shear stresses under shear flow. Thus, multiple bond formation arising from greater normal forces in recirculating flow permits monocytes to adhere at higher shear stresses.
A 3D unsteady flow analysis in a doubly constricted arterial vessel
Authors: Kumar B.V. Rathish , Yamaguchi T. , Liu H. , Himeno R.
Published: November 2024

The aim of this study is to examine the interaction between two mild atherosclerotic proliferations spaced apart by a distance S by analyzing their influence on flow structure, pressure drop and stress field in an arterial vessel under pulsatile flow conditions. This has been achieved numerically by employing a time accurate, cell centered finite volume method in solving the Navier–Stokes equations governing the 3D unsteady flow dynamics in a conceptual model of an multiply constricted arterial vessel. In comparison to the pressure drop across a single stenosis, nearly a 50% increase in the late systolic and early diastolic pressure drops has been observed across the two mild constrictions when they are spaced within a distance of S≤4. When S≤4, more than a 25% reduction in the peak systolic wall shear stress (WSS) on the downstream constriction is noted.
A simple computational model of the right coronary artery on the beating heart – effects of the temporal change of curvature and torsion on the blood flow
Authors: Hayashi Hiroyuki , Yamaguchi Takami
Published: November 2024

A computational fluid dynamics study was conducted using a simplified model of the right coronary artery, which deforms with contraction of the heart. The right coronary artery was modeled using an ordinary helix, whose torsion and curvature changed in time with the contraction and dilatation of the heart which was modeled as a cylinder. In the computational result, the flow in the model right coronary artery was thought to be more affected by the change of the curvature compared to that of the torsion.