bluuebunny/crossref_metadata_2025 huggingface dataset:
Friend, foe, or forget ‘em?: The quality of LGBTQ adult sibling relationships
Authors: Reczek Rin , Stacey Lawrence , Dunston Chloe
Published: January 2022

Objective

The present study aims to understand how LGBTQ adults characterize the quality of their adult sibling ties, and how the type of sibling relationship (e.g., full, step, half, chosen) informs this characterization.

Background

An intragenerational conflict‐solidarity‐ambivalence frame is developed to theorize and empirically examine sibling relationships.

Methods

Drawing on an intragenerational conflict‐solidarity‐ambivalence frame, we analyze qualitative in‐depth interview data from 67 LGBTQ adults who identify as having a sibling.

Results

The quality of sibling ties was characterized in three primary ways: solidary, wherein an adult sibling perceived their sibling bond(s) as high quality due to exchanges of social/emotional/financial/instrumental support and connection, including LGBTQ support; conflictual, wherein the adult sibling tie is painful because a sibling is problematic, is unsupportive of an LGBTQ identity, or because a sibling creates conflict in a relationship with a parent; and tangential, wherein the sibling relationship was never bonded, is distanced, or siblings have their “own” families and are thus deemed inconsequential. Only full siblings were typified as conflictual, while all sibling types were solidary. Full, step, and half siblings only are characterized as tangential. Differences in sibling quality across gender and sexuality are discussed.

Implications

This study contributes to the growing body of research on the quality of family ties in adulthood, providing further insight into how a socially marginalized group is supported, harmed, or perhaps unfazed by their sibling relationships.
Productive, physiological and nutritional responses of laying hens fed different dietary levels of turmeric powder
Authors: Fawaz Mohamed A. , Südekum Karl‐Heinz , Hassan Hamdy A. , Abdel‐Wareth Ahmed A. A.
Published: January 2022

This study aimed to determine the impact of supplementation of turmeric powder on laying performance, egg quality, nutrient digestibility and some blood metabolites in laying hens. A total of one hundred and twenty Bovans Brown laying hens (55 weeks old) were assigned to one of four treatment diets (n = 30) for 12 weeks including turmeric powder at 0, 2.5, 5 or 7.5 g/kg respectively. The results revealed that egg production, egg weight and egg mass were significantly increased (p < 0.05), and the feed conversion ratio was significantly improved (p < 0.012) with increasing levels of turmeric in the laying hen diet. Egg thickness and Haugh unit were linearly increased (p < 0.01) with increasing supplementation levels. Moreover, compared with the control diet, the levels of turmeric powder supplementation significantly improved nutrient digestibility (p < 0.001). Moreover, the serum metabolic profile revealed that serum total cholesterol, aspartate aminotransferase, creatinine and urea concentrations were linearly decreased with increasing turmeric powder supplementation to hen diets. In conclusion, the inclusion of turmeric powder at 2.5, 5 or 7.5 g/kg diet improved egg production, nutrient digestibility, egg quality and serum metabolic profile and may be used as a feed additive in laying hens' nutrition. However, results indicate that the best improvement was observed when 5 g/kg were supplemented.
Experimental sympatry suggests geographic isolation as an essential reproductive barrier between two sister species ofPedicularis
Authors: Tang Ju , Sun Shi‐Guo , Huang Shuang‐Quan
Published: January 2022

Although mechanical isolation mediated by shared pollinators has been considered as a classic model of pollinator‐mediated floral isolation inPedicularis, a superdiverse genus in Hengduan Mountains, southwest China, there has been no empirical study of interspecific pollen flow between closely related species. We examined reproductive barriers at six different stages betweenPedicularis cranolophaandPedicularis tricolor, two sister species. The two sister species were geographically isolated from each other based on our field survey and the records of herbarium specimens. Translocation experiments showed that flowering phenology partly overlapped and bumblebee pollinators did not discriminate between flowers of the two species. Bumblebee interspecific moves could mediate interspecific pollination as traced using fluorescent powder, in which pollen analogs placed on one species were transferred to the stigmas of the other species in experimental plots containing both species. Heterospecific pollen tubes grew in the style as well as conspecific pollen in hand‐pollination experiments. Reciprocal hybridization between the two species could produce (partially) viable seeds, suggesting weak post‐pollination barriers. Our results showed that geographic isolation was an important barrier of two species, and the total reproductive isolation between two species was incomplete when without geographical isolation. The formation of Big Snow Mountains could introduce an important pre‐zygotic reproductive barrier between the two sister species ofPedicularis; such geographical isolation could be responsible for allopatric speciation, giving a clue to understanding the rapid radiation on mountain areas.
Bear diets and human–bear conflicts: insights from isotopic ecology
Authors: Falconi Nereyda , Carlo Tomás A. , Fuller Todd K. , Destefano Stephen , Organ John F.
Published: January 2022

Bears, Ursidae, are considered omnivores, except for giant pandas Ailuropoda melanoleuca and polar bears Ursus maritimus. However, omnivory includes a wide range of dietary variation and trophic positions, making bear dietary ecology unclear. We inferred bear trophic positions from δ15N (‰) values and examined their correlation with diets reported in the literature, including frequency of human–bear conflicts (livestock predation and crop damage incidents). Overall, 15N signatures were consistent with diet estimates. Bear species with higher 15N signatures differed more from each other, including cases of large regional intraspecific variance, than bear species with lower 15N signatures. Bear trophic position and frequency of reports of human–bear conflicts were uncorrelated, suggesting that livestock predation by bears is an opportunistic behaviour rather than a response to food availability dynamics.
Death and Dying in Carceral America: The Prison Hospice as an Inverted Space of Exception
Authors: Sharp Lesley A.
Published: January 2022

In America's prisons, long‐term incarceration carries fears that one could die in prison alone and abandoned. Death by incarceration looms as inescapable for myriad inmates who are terminally ill or “graying” in prison. These realities inform this study of a prison‐based hospice program staffed by male inmate volunteers in a mixed medium/maximum security facility. Of special concern are the experiences of the men who sit by the bedside of others who are dying. I begin with the assumption that prisons loom as states of exception, epitomized by the realities of substandard prison medicine, the devaluation of care as anathema to prison survival, and the persistent neglect of the ill and aging. The ethos and practices associated with inmate‐driven end‐of‐life care demarcate an inverted space of non‐judgmental praxis that simultaneously envelopes the dying man while also instigating self‐reflection, change, and self‐care among inmate hospice volunteers.
Revisiting old truths: The evolution of male coloration in guppies as a function of predation
Authors: Fuller Rebecca C.
Published: January 2022

The Trinidadian guppy, Poecilia reticulata, is a long‐studied model for the evolution of trade‐offs in male nuptial coloration as a function of female mating preferences vs. predation risk. Previous work suggests that female mating preferences favour the evolution of increased conspicuous male coloration in low predation populations. In contrast, high predation risk shifts the balance towards reduced conspicuous coloration. In a From the Cover article in this issue of Molecular Ecology, Yong, Croft, Troscianko, Ramnarine, and Wilson (2021) use visual detection models to estimate the “conspicuousness” of male colour patterns as seen by guppies and their predators. The study fails to find robust patterns of increased conspicuousness in low predation populations. Only one of eight measures of conspicuousness showed parallel changes between high and low predation regimes, forcing us to reconsider the validity and repeatability of this classic example of parallel evolution.
Patients' perspectives on medical students' professionalism: Blind spots and opportunities
Authors: Haney Simon , Rowland Paula , Ginsburg Shiphra
Published: January 2022

Background

Research has acknowledged the value of patients as essential stakeholders in medical education, yet educators have not adequately incorporated patients' perspectives into medical students' developing professionalism. Our purpose was to explore patients' perceptions of professional behaviour in medical students as a first step to considering patients' potential roles in assessing professionalism.

Methods

Building on the existing framework of the ‘disavowed curriculum’, we used a constructivist grounded theory approach to interview and analyse data from 19 patients (11 W, 8 M) at one urban hospital. Each participant watched five video scenarios that depict professionally challenging situations commonly faced by medical students, after which they were asked to put themselves in the position of both the patient and the student depicted in each scenario, and to discuss what they felt would be appropriate or inappropriate behaviours from each perspective.

Results

Patients' responses replicated all elements of the disavowed curriculum, including principles of professionalism, the student's affect or internal factors, and potential implications of actions. Their responses reflected avowed, unavowed and disavowed rationales. Participants also identified novel principles, including hide dissension in the ranks, respect privacy, advocate for yourself and have trust in the system. Patients conveyed an understanding of the multiple competing factors students must balance (e.g., providing optimal care while maximising educational opportunities) and appeared to empathise with some of the pressures students face.

Conclusions

Our findings point to significant blind spots in previous research based on faculty and student perspectives of professionalism. Knowing what patients perceive as important will allow educational and assessment efforts to be refined to reflect their values. Our work begins the process of understanding how best to include patients in the assessment of medical learners.
One‐Stage Closed Intramedullary Nailing for Delayed Femoral Fracture in Multiple Injured Patients
Authors: Yan Ruijian , Wu Yifan , Qi Yiying , Li Hang , Dong Shurong , Feng Gang
Published: January 2022

Objective

To tackle the challengeable dilemma of delayed femoral fracture, a technique of fixator‐assisted closed reduction and intramedullary nailing at one stage was introduced herein and its clinical results were investigated.

Methods

A retrospective study was conducted on delayed femoral shaft fracture between February 2008 and January 2017. The multiple injured patients aged from 18 to 60 years with delayed femoral fracture was included. All patients were treated by one‐stage internal fixation technique and followed up for more than 1 year. Outcome measures including the operation time, intraoperative blood loss and limb alignment, healing time of fracture, visual analog scale (VAS), and range of knee motion were recorded and evaluated.

Results

A total of 13 patients (16 sides) with a mean injury severity score (ISS) of 32.77 ± 9.98 (range, 19 to 52) participated in the investigation. The median length of time‐after‐fracture was 38 days (range, 21 to 110 days). The average shortening distance of the fracture ends was 35.48 ± 19.24 mm (range, 10.00 to 79.00 mm). The average surgery time was 192.19 ± 29.38 min for unilateral femoral fracture, with blood loss of 587.50 ± 232.02 ml. The postoperative discrepancy of lower limb was 3.87 ± 2.52 mm. No patient had vascular and neurologic complications due to the lengthening. All fractures healed successfully with a mean time of 2.98 ± 0.57 months. The mean VAS and maximal knee flexion were 1.63 ± 1.09 and 131.25° ± 5.32° at final follow‐up, respectively.

Conclusions

Our findings indicated that fixator‐assisted closed reduction and intramedullary nailing at one stage is an effective treatment for delayed femoral fracture with satisfactory functional recovery.
Is Plating Fixation Through the Kocher–Langenbeck Approach for Associated Posterior Wall Fragment Indispensable in Both‐Column Acetabular Fractures?
Authors: Tian Siyu , Zhang Ruipeng , Liang Shaobo , Yin Yingchao , Ma Lijie , Liu Guodong , Guo Xiaodong , Hou Zhiyong , Zhang Yingze
Published: January 2022

Objective

The treatment methods for posterior wall (PW) in both‐column acetabular fractures are controversial. The purpose of this study was to compare reduction quality, clinical outcomes, and complications of nonfixation for posterior wall fragment and plating via the Kocher–Langenbeck (KL) approach after anterior surgical procedures in both‐column acetabular fractures.

Methods

Forty‐nine patients with both‐column acetabular fractures associated with PW fixed via iliac fossa and Stoppa approaches from October 2012 to October 2017 were recruited into this study and were divided into two groups: Nonfix group (nonfixation for PW) and KL group (PW plating through the KL approach). Operation duration, intraoperative blood loss, reduction quality, fracture healing, and relevant complications of patients were reviewed. Merle d'Aubigné scores were used for assessing functional outcome.

Results

The mean blood loss and operation durations were lower in Nonfix group than in KL group (both p < 0.05). The mean hospital stay durations were (18.54 ± 6.42) days and (21.17 ± 7.32) days in groups Nonfix and KL, respectively (p = 0.186). All fractures healed well with no significant difference in union time between the two groups (p = 0.210). The rates of satisfactory reduction were 84.62% (22/26) in Nonfix group and 86.96% (20/23) in KL group (p = 1.000). The mean Merle d'Aubigné scores were 15.62 ± 2.28 in Nonfix group and 16.17 ± 2.19 in KL group (p = 0.388). The complication rates were 7.69% (2/26) in Nonfix group and 34.78% (8/23) in KL group (p = 0.046).

Conclusions

For both‐column acetabular fractures associated with PW fragment, although fixation of PW was not performed after anterior surgical procedures, satisfactory outcomes could also be obtained. However, nonfixation was a less invasive choice with a lower complication rate.
Aus rice root architecture variation contributing to grain yield under drought suggests a key role of nodal root diameter class
Authors: Liao Qiong , Chebotarov Dmytro , Islam Mohammad S. , Quintana Marinell R. , Natividad Mignon A. , De Ocampo Marjorie , Beredo Joseph C. , Torres Rolando O. , Zhang Zhenhua , Song Haixing , Price Adam H. , McNally Kenneth L. , Henry Amelia
Published: January 2022

The aus rice variety group originated in stress‐prone regions and is a promising source for the development of new stress‐tolerant rice cultivars. In this study, an aus panel (~220 genotypes) was evaluated in field trials under well‐watered and drought conditions and in the greenhouse (basket, herbicide and lysimeter studies) to investigate relationships between grain yield and root architecture, and to identify component root traits behind the composite trait of deep root growth. In the field trials, high and stable grain yield was positively related to high and stable deep root growth (r = 0.16), which may indicate response to within‐season soil moisture fluctuations (i.e., plasticity). When dissecting component traits related to deep root growth (including angle, elongation and branching), the number of nodal roots classified as 'large‐diameter' was positively related to deep root growth (r = 0.24), and showed the highest number of colocated genome‐wide association study (GWAS) peaks with grain yield under drought. The role of large‐diameter nodal roots in deep root growth may be related to their branching potential. Two candidate loci that colocated for yield and root traits were identified that showed distinct haplotype distributions between contrasting yield/stability groups and could be good candidates to contribute to rice improvement.
Intracellular Ca2+ accumulation triggered by caffeine provokes resistance against a broad range of biotic stress in rice
Authors: Park Jong‐Chan , Yoo Youngchul , Lim Hyemin , Yun Sopheap , Win Kay Tha Ye Soe , Kim Kyung‐Min , Lee Gang‐Seob , Cho Man‐Ho , Lee Tae Hoon , Sano Hiroshi , Lee Sang‐Won
Published: January 2022

Chemical pesticides are still frequently overused to diminish such crop loss caused by biotic stress despite the threat to humans and the environment. Thus, it is urgent to find safer and more effective defense strategies. In this study, we report that caffeine, implanted through a transgenic approach, enhances resistance against variable biotic stresses in rice without fitness cost. Caffeine‐producing rice (CPR) was generated by introducing three N‐methyltransferase genes involved in the biosynthesis of caffeine in coffee plants. The CPR plants have no differences in morphology and growth compared to their wild‐type counterparts, but they show strongly enhanced resistance to both bacterial leaf blight, rice blast, and attack of white‐backed planthoppers. Caffeine acts as a repellent agent against rice pathogens. Moreover, caffeine triggers a series of Ca2+ signalling‐like processes to synthesize salicylic acid (SA), a hormone associated with plant resistance. In CPR, phosphodiesterase was inhibited by caffeine, cAMP and cGMP increased, intracellular Ca2+ increased, phenylalanine lyase (PAL) was activated by OsCPK1, and SA synthesis was activated. This finding is a novel strategy to improve resistance against the biotic stresses of crops with a special type of defense inducer.
Use of DCD organs: Expanding the donor pool to increase pediatric transplantation
Authors: Hwang Christine S. , MacConmara Malcolm , Dick André A. S.
Published: January 2022

The number of children being listed for transplant continues to be greater than the number of available organs. In fact, over the past decade, rates of liver and kidney transplants in pediatric transplantation are essentially unchanged (Am J Transplant. 2020;20:193 and Am J Transplant. 2020;20:20). The use of DCD donors offers a potential solution to organ scarcity; however, the use of DCD organs in pediatric transplantation remains a rare event. Pediatric transplants done using carefully chosen DCD donor organs have shown to have outcomes similar to those seen with the use of donation after brain death (DBD) donors. Herein, we review the literature to examine the utilization of DCD livers and kidneys, outcomes of these allografts, and assess if DCD organs are a viable method to increase organ availability in pediatric transplantation.
Vascular traits of stem galls: Cell increment versus morphogenetic constraints in wood anatomy
Authors: Jorge N. d. C. , Freitas M. d. S. C. , Caffaro R. M. , Vale F. H. A. , Lemos‐Filho J. P. , Isaias R. M. d. S.
Published: January 2022

Eremanthus erythropappus hosts globoid stem galls induced by Neolasioptera sp. (Diptera: Cecidomyiidae) close to the stem apex, which do not compromise the shoot apical meristem (SAM). We hypothesize that maintenance of the SAM, as well as the increasing number of leaves per branch and of galled stem lengths and diameters, are a consequence of alterations in vascular cells and, consequently, in the priority for water flow from non‐galled stems to the stem galls. Our study focuses on the globoid stem galls to evaluate if gall induction and development promote changes in structure and function of secondary xylem cells.

Anatomical, cytological, histometric and physiological methods were used to analyse non‐galled stem branches (NGS), mature globoid stem galls and stem portions below and above the galls.

These analyses revealed that vessel elements are larger in stem galls and in stem portions above the galls. Under Neolasioptera sp. induction activity, the vascular cambium of E. erythropappus produces less numerous but larger vessel elements and overproduces parenchyma cells.

Contrary to the vascular constriction hypothesis proposed for bacterial galls, the vascular traits of the Neolasioptera sp. stem galls on E. erythropappus result in priority for water flow to galls and the non‐galled portions above the galls, allowing the maintenance of galled stem growth and development.
Phoma black stem severity and phytoestrogen production in annual Medicago spp. is primarily determined by interaction of cultivar and pathogen isolate
Authors: Omidvari Mahtab , Flematti Gavin R. , You Ming Pei , Abbaszadeh‐Dahaji Payman , Barbetti Martin J.
Published: January 2022

Phoma black stem and leaf spot disease (caused by Phoma medicaginis) not only diminishes forage and seed yield but stimulates production of detrimental phytoestrogens in annual Medicago spp. This study aimed to evaluate relationships between disease development from five isolates of P. medicaginis on 16 cultivars with production of coumestrol and 4′‐O‐methylcoumestrol. In the presence of P. medicaginis, Sava had the highest coumestrol and 4′‐O‐methylcoumestrol (640 and 85 mg/kg, respectively) followed by Caliph (253 and 15 mg/kg, respectively). In the absence of P. medicaginis, Jemalong and Paragosa showed highest and lowest coumestrol (137 and 0 mg/kg, respectively). 4′‐O‐methylcoumestrol was not produced in disease‐free plants, but coumestrol was. Disease incidence and severity on leaves and on petiole/stems, and consequent leaf yellowing severity ranged from 5%–98.7%, 0%–100%, 4.4%–98.7%, 1.7%–100%, and 0%–85%. Sava, Paraponto, Harbinger, and Serena were most susceptible, while Tornafield and Caliph were least susceptible. There was significant overall positive correlation of disease incidence/severity factors across cultivars (p < 0.01) with both coumestrol and 4′‐O‐methylcoumestrol. Jemalong was least responsive and Paragosa and Sava most responsive to coumestrol production following P. medicaginis inoculation. Coumestrol in inoculated Paragosa increased to 373 mg/kg in comparison with 0 mg/kg in controls. These findings are of critical importance towards developing less disease‐susceptible annual Medicago spp. producing less detrimental phytoestrogens. Least susceptible cultivars like Tornafield and Caliph can be used to manage yield loss, whilst least responsive cultivars to phytoestrogen production like Caliph also can help to reduce phytoestrogen production.
A novel experimental method to characterise the shear strength of concrete based on pre‐stressed samples
Authors: Forquin Pascal , Abdul‐Rahman Reem , Saletti Dominique
Published: January 2022

The present paper describes a novel experimental method for characterising the confined shear strength of concrete or rock‐like materials based on the use of pre‐stressed sample. This method, called PS‐PTS (Pre‐Stressed Punch‐Through‐Shear), employs a metallic confinement cell that is first quasi‐statically deformed so the concrete sample can be introduced in between the cell jaws. The confinement force is transmitted to the sample in the unloading stage. It is shown that this initial pre‐load level can be predicted by an elastic closed‐form solution. Strain‐gauges glued on the cell allow the confinement level applied to the sample to be experimentally measured during the pre‐stressing stage and the shear stage. In the next stage, the central part of the sample is subjected to a differential displacement towards the lateral parts by means of a hydraulic press so the confined shear strength of the tested material can be deduced. The results are compared to the data previously obtained with an “oedometric” confinement cell in terms of confinement stresses and shear strength.

Highlights

A Pre‐Stressed Punch‐Through‐Shear technique is proposed based on pre‐loaded cell.

A close‐form solution predicts the level of pre‐load applied to the sample.

The cell is instrumented with strain gauges, so the applied forces are measured.

The technique is applied to characterise the confined shear strength of concrete.

Results are compared to those obtained with the ‘Oedo‐PTS’ testing method.
Measuring user experience of care among caregivers of sick children: Validation and descriptive analysis in a sample of 75 health facilities in rural Tanzania
Authors: Clarke‐Deelder Emma , Eliakimu Eliudi , Mbatia Redempta , Bohren Meghan A. , Mashasi Irene , Larson Elysia
Published: January 2022

Objective

User experience is an important aspect of quality of care that is highly valued by patients. However, there are currently no validated tools for measuring user experience among caregivers of sick children in low‐ and middle‐income countries. We aimed to develop and validate a measure of user experience in this population in primary healthcare facilities in rural Tanzania, where major quality improvement efforts to date have not included a large focus on user experience. We then aimed to describe variation in user experience between and within facilities.

Methods

Informed by theory and formative qualitative research, we developed questions to measure user experience across three domains: prompt care, respect, and communication. We then conducted interviewer‐administered surveys with caregivers of sick children. Using survey data, we conducted psychometric analyses to inform the development of a composite measure of user experience. Finally, we used multilevel models to describe variation in user experience and examine associations with facility, patient, and caregiver characteristics.

Results

Surveys were completed by 1085 caregivers across 75 facilities. In exploratory factor analysis, user experience items did not group according to theoretical domains. We therefore assessed items individually and designed a single 8‐item additive measure of user experience. Using this composite measure, and adjusting for differences in case mix across facilities, we found that 69% of variation in user experience was within facilities and 31% was between facilities. Smaller facility size and more caregiver education were positively associated with user experience.

Conclusions

We found that user experience varied significantly across health facilities in rural Tanzania, highlighting opportunities for improvement. Measurement tools are needed to inform efforts to improve user experience and monitor changes over time. The scale developed in this study could serve as a starting point for the measurement of user experience among caregivers in similar settings.
Mechanical Responses of the Fingertip During Grasp-and-Lift Tasks
Authors: Kimmelman Jay S. , Dennerlein Jack Tigh , Howe Robert D.
Published: January 2022

The human fingertip and its viscoelastic fingertip pad mediate much of our mechanical interaction with the environment. In manipulation tasks like grasping and lifting, soft-tissue deformation and passive joint rotation of the fingertip may be an important component for fine motor control and dexterity. Johansson and Westling [1] have extensively studied fingertip forces and neural responses during grasp-and-lift tasks, but their work is mainly limited to the description of how force develops throughout the lift. Pawluk [2] and Serina et al. [4] have examined fingertip pad deformations under compressive loading only. Our goal is to develop a more complete model of fingertip response during grasp-and-lift, including changing pressure distributions, soft-tissue deformation, orientation of the fingertip, and their effects on manipulation. We hypothesize that during a typical grasp and lift task, the centroid of pressure of the fingertip moves upward due to fingertip pad deformation as well as passive rotation of the metacarpal and interphalangeal joints.
Developing a Finite Element Model of a Human Femur From Magnetic Resonance Images
Authors: Murphy Benjamin M. , Todd Beth A. , Cuttino James F. , Shackelford Linda C.
Published: January 2022

Under the conditions of weightlessness, astronauts have a tendency to exhibit bone mineral loss in their spines and lower extremities (Oganov et al., 1992). According to Wolf’s law, bone adapts to functional demands by remodeling to reflect the distribution of stress placed on the bone (Bentzen et al., 1987). To prevent remodeling, NASA has suggested a plan of resistive exercises to produce the appropriate stress distributions to counteract the remodeling process. Prolonged bed rest studies are used by NASA to simulate a zero gravity environment on earth. During these bed rest studies, different exercises are performed on a device called the horizontal exercise machine (HEM). These exercises are the same type as those that are proposed for space flight.
Strain Fields of the Inferior Glenohumeral Ligament Surface in a Subluxed Shoulder: A Stereoradiogrammetric Study
Authors: Malicky David M. , Soslowsky Louis J. , Bey Michael J. , Mouro Cameron M. , Kuhn John E.
Published: January 2022

The inferior glenohumeral ligament serves as a critical restraint to anteroinferior dislocation. This study utilizes a biomechanical model to determine the strain field in the inferior glenohumeral ligament (IGHL) in a subluxed shoulder. Spherical lead object markers were carefully attached to the IGHL surface in a grid pattern. Two capsular configurations were used for strain field calculations: a “nominal” state and a “strained” state. For the nominal state, the capsule was inflated in neutral rotation with low pressure air. For the strained state, the humerus was externally rotated and anteroinferiorly subluxed. Stereoradiographs were taken of both configurations and markers digitized. Three-dimensional coordinates of object markers were reconstructed and strain fields calculated. Maximum principal strains on the glenoid side of the IGHL were significantly greater than the humeral side, and strain fields were highly variable over the region studied. This study reports an accurate method for measuring planar strains in a three-dimensional membrane.
Artery Wall Adaptation in Health and Disease
Authors: Zarins Christopher K.
Published: January 2022

Artery walls respond to hemodynamic influences of blood flow and blood pressure. Flow and pressure are critical during growth and development as well as adult life. Blood vessels adapt and respond with changes in diameter and wall thickness to accommodate changing hemodynamic environments and needs. Pathologic processes such as: aneurysmal wall degeneration, aneurysm formation and intimal hyperplasia, are similarly influenced by hemodynamic conditions. Hemodynamic factors such as wall shear-stress, particle residence time and heart rate can profoundly influence plaque localization. Hemodynamic conditions can be markedly altered by exercise or drug manipulation and may significantly influence clinical manifestation of vascular disease. The hemodynamic factors important in atherosclerotic vascular disease and the rationale for the beneficial effect of exercise will be emphasized.
Evaluation of Valvular Regurgitation in a Porcine Bioprosthetic Valve
Authors: Smith Barry K. , Anayiotos Andreas S. , Kolda Michal , Nanda Navin C.
Published: January 2022

The diagnosis and quantification of valvular regurgitation in patients is important in clinical decision making. The purpose of this study is to define precise and practical methods to predict regurgitant flow through a defective porcine bioprosthetic valve by non-invasive ultrasound based modalities. The investigation combines studies of the velocity flowfield by Doppler Ultrasound as well as the regurgitant orifice morphology by 3-D echocardiography.
CFD-Based Design Optimization of a Three-Dimensional Turbo Blood Pump
Authors: Burgreen Greg W. , Antaki James F.
Published: January 2022

The analysis capabilities of CFD are beginning to be recognized by the biomedical community as a means to effect design improvements. Specifically, CFD is being used as a tool to help designers suggest improvements in the fluid dynamic behavior within prosthetic devices or pertaining to a surgical procedure. Some flow problems that have been analyzed with this intent in mind include blood pumps of rotary [1,2] and positive displacement [3] types and vascular grafts and stents [4].
Determination of Microscopic Wall Shear Stress Distribution on Endothelial Cell Model
Authors: Fukushima Shuichiro , Deguchi Takaaki , Nishida Masahiro , Kaibara Makoto , Oka Kotaro , Tanishita Kazuo
Published: January 2022

Wall shear stress induced by blood flow affects morphology and physiology of endothelial cells. The specific mechanisms alternating shapes and functions have not been identified in endothelial cells, because of the lack of a detailed description of the flow near the cell surface. To clarify the mechanism, an analysis of the flow on subcellular scale is required. We therefore developed velocimetry using expanded cell model (Fukushima et al. 1997). The method, however, needs some improvements in order to discuss wall shear stress distribution on subcellular scale. In this paper we deal with determination of three-dimensional velocity field and wall shear stress distribution and verify the reliability by comparing experimental results with theoretical solution.
Mechanistic Model of Arterial Thrombosis in Collagen-Coated Stenoses
Authors: Wootton David M. , Markou Christos P. , Hanson Stephen R. , Ku David N.
Published: January 2022

A mechanistic model of arterial thrombosis has been developed, based on platelet transport by convection and shear-enhanced diffusion, and platelet adhesion at a lumped kinetic rate. The model is compared to platelet deposition on collagen-coated stenoses in an ex vivo thrombosis experiment that uses non-anticoagulated blood. In the converging regions of the stenosis, the model reproduces the spatial platelet deposition pattern, and matches deposition rates reasonably well. The model suggests that platelet thrombosis on type I collagen in stenotic arterial flow is transport-dominated.
Numerical Simulation of Antibody Penetration in a Solid Tumor Nodule Using Finite Element Method
Authors: Banerjee Rupak K. , Praxmaraer Meinrad , Dilber Ilhan , Bungay Peter , van Osdol William , Sung Cynthia
Published: January 2022

The high binding specificity that monoclonal antibodies exhibit has led to great interest in using them to target tumor-associated antigens. The antibody may be coupled to a radionuclide or cytotoxic drug to create a tumor-targeted reagent that can be used to identify sites of metastatic disease and/or deliver a lethal substance to the tumor cells. However, successful application of these compounds in a clinical setting has been hindered by a poor understanding of the factors that govern antibody accumulation in a tumor. We have used a finite element method to develop a pharmacokinetic model describing the uptake of systemically-administered antibody in an early, prevascular spherical tumor nodule embedded in normal tissue. The model incorporates such processes as plasma kinetics, transcapillary transport, interstitial diffusion, binding reactions, lymphatic clearance, and antigen internalization.
Clinical Applications of CFD, Visualization and Virtual Reality in Cardiovascular Medicine
Authors: Taylor Charles A.
Published: January 2022

The introduction of computational tools to construct and evaluate models of the anatomy and physiology of human biological systems can enable researchers to test hypotheses regarding abnormal conditions, examine treatments, and, in the long term, enable clinicians to predict the outcome of alternative treatment plans. The computational methods underlying diagnostic imaging are prevalent in clinical environments. However, this diagnostic information, typically expensive to acquire, is provided to the physician without the tools necessary to evaluate the outcome of various treatments. The individual variability and inherent complexity of human biological systems is such that imaging data alone is insufficient to predict the outcome of a given treatment.

Hemodynamic conditions, including velocity, shear, and pressure, play an important role in the modulation of vascular adaptation and the localization of vascular disease. Consequently, understanding the local hemodynamic environment in a region of the vascular system has been an important field of research in the last two decades. In the coming years, computational fluid dynamics methods will move beyond the academic research domain and be implemented in Computer Aided Surgical Planning software. These methods will augment the information available from medical diagnostic imaging to define patient-specific predictive computer models.

Critical issues in the application of CFD, Visualization and Virtual Reality to Cardiovascular Medicine are examined. A software system developed for Computer Aided Surgical Planning which provides an integrated set of tools to test hypotheses regarding the effect of alternate treatment plans on vascular hemodynamics is described.
The Role of Spinal Catheters in Anesthetic Maldistribution
Authors: Myers Matthew R. , Rinaldi Jean E.
Published: January 2022

The ability of small-diameter catheters to uniformly distribute anesthetic within the subarachnoid space of the spinal column was studied, both experimentally and computationally. It was found that there is minimal anesthetic mixing associated with the smallest catheters, both in the free jet emanating from the catheter and the flow interacting with the boundaries of the subarachnoid space. These results may help explain recent occurrences of neurological injuries associated with the use of small-bore catheters for continuous spinal anesthesia.
Comparison Between Calculated Physiologic and Measured Phasic Pressure Gradients Across Human Stenoses Remodeled by Coronary Angioplasty
Authors: Banerjee Rupak K. , Back Lloyd H.
Published: January 2022

The coupling of computational hemodynamics to endovascular diagnostics in human coronary artery stenoses during angioplasty procedures was evaluated. Calculated mean pressure gradients were much lower for physiologic flow than measured mean pressure gradients. The narrower flow cross-section with the catheter present effectively introduced a tighter stenosis than the enlarged residual stenoses after balloon angioplasty; thus elevating the pressure gradient and reducing blood flow during the measurements.
Human Drop Tests of Restrained Occupants in a Small Passenger Car Compartment
Authors: Friedman Keith , Friedman Donald
Published: January 2022

The paper describes experiments involving restrained human volunteer tests in drop tests involving velocities up to 4.2 meters/sec.

The effect of roof crush on restrained occupants has often been discussed without regard to the headroom available, effectiveness of belts, and location of roof crush. In this paper the question of the ability to protect a simply restrained occupant in an environment in which the roof does not crush is addressed.

The results show that, with an effectively designed occupant rollover protection system, restrained occupants of various sizes do not experience serious injurious neck injuries without roof crush.
Dynamic Bending Strength of the Human Forearm
Authors: Pintar Frank A. , Yoganandan Narayan , Voo Liming , Kleinberger Mike
Published: January 2022

The present study was conducted to determine the dynamic bending strength of the human forearm. A total of 30 human cadaver forearm specimens were tested using a three-point bending method to failure at 3.3 to 7.6 m/s speeds. Results indicated significantly (p < 0.01) greater mean failure moment for males (113 ± 39 Nm) compared to females (66 ± 25 Nm). The mean failure bending moment for all specimens was 94 Nm. The smaller sized occupant with lower bone mineral however, has one-half of this strength (approximately 45 Nm). The failure moment of the human forearm was found to be most highly correlated to bone mineral density and forearm weight. The present investigation offers quantitative information regarding strength of the human forearm useful for design of injury-mitigating devices.
Impact Severity During a Fall Is Decreased by Lower Extremity Muscle Contractions During Descent
Authors: Sandler Reuben , Robinovitch Stephen N.
Published: January 2022

Falls are a major cause of injury in the elderly, including the vast majority of hip and wrist fractures, and a considerable portion of vertebral fractures. In the event of a fall, one’s risk for such an injury depends on bone strength, and the configuration and kinetic energy (KE) of the body at the instant it contacts the ground. Consideration of acts such as sitting and squatting suggests that a major determinant of KE is the amount of energy “absorbed” (or negative work performed) during the descent phase of the fall by eccentrically-contracting lower extremity muscles. In the present study, we used a computational model of backwards falling to address the following questions: (1) what degree of impact energy attenuation might be achieved through muscle contraction during the descent phase of falling? and (2) what is the relative importance of muscle contractions at the hip, knee, and ankle in attenuating impact energy?
Development and Validation of a Porohyperelastic Finite Element Model of a Mouse Tail Disc to Investigate Tissue Remodelling
Authors: Duncan Neil A. , Colliou Olivier K. , Lotz Jeffrey C.
Published: January 2022

We developed a porohyperelastic finite element model of the intervertebral disc of a mouse tail. The model prediction of the axial stress-strain response was in good agreement with our experimental results. The stresses in the inner annulus were predicted to be dramatically altered by creep loading. These changes, when compared with our in vivo animal model of disc degeneration in a mouse tail disc, suggested that the biologic changes observed in the inner annulus are consistent with remodelling of the tissue due to an altered stress environment.
Regional Load Sharing in Cervical Spine Intervertebral Disc
Authors: Kumaresan Srirangam , Yoganandan Narayan , Pintar Frank A. , Maiman Dennis J.
Published: January 2022

An anatomically accurate, fully three-dimensional, geometrically and materially nonlinear, and experimentally validated finite element model of the human lower cervical spine was used to study the intervertebral disc biomechanics. The internal axial and shear forces resisted by the ventral, middle and dorsal regions of the intervertebral disc under the axial and eccentric loading modes were quantified. The ventral region resisted higher axial forces with considerable variation from compression-flexion to compression-extension loading. This may explain the higher incidence of osteophytes in this region of the cervical spine. The higher shear forces resisted by the dorsal region of the disc coupled with the presence of bilateral uncovertebral joint anatomy may account for the occurrence of disc herniation in the dorso-lateral region of the spine.
Biomechanical Stability of Multi-Level Inter-Body Cervical Strut-Graft Fusion With Posterior Plating Instrumentation
Authors: DiAngelo Denis J. , Vossel Keith A. , Foley Kevin T. , Rampersaud Y. Raja
Published: January 2022

Strut-graft fusion with supplemental instrumentation is an accepted surgical treatment for multi-level cervical disease. There are many surgical methods for decompressing and reconstructing the cervical spine, e.g., anterior: multi-level discectomy, multi-level interbody strut-graft fusion (SG), multi-level strut-graft with anterior plate instrumentation, or posterior: multi-level laminectomy with posterior lateral mass plating instrumentation. A relatively new surgical approach that combines these methods is multi-level strut-graft fusion with posterior plating instrumentation (SGPP). Although the surgery should restore the mechanical integrity of the operated spine, little is known of the load-sharing mechanics between the SG and posterior instrumentation. Clinically, strut-grafted constructs fail by pistoning of the SG into the adjacent vertebrae, dislodgment of the SG at the vertebral interfaces, SG fracture, hardware breakage, or screw-plate extrusion. The objective of the study was to determine the biomechanical stability of SGPP spinal constructs and to study the influence of posterior plates on strut-graft loading mechanics in vitro.
The Interaction of Muscle Forces With Constraints of Passive Elements in the Knee Joint
Authors: Liu Wen , Maitland Murray
Published: January 2022

A two-dimensional knee model was developed to determine the interaction between muscle forces and passive constraints of the knee joint. The simulated results showed that increased hamstring muscle force reduced anterior shift of the tibia in ACL-deficient knee at the mid-stance of gait. However, it may not be realistic to maintain normal joint position in ACL deficient knee.
Representation of Anisotropy in Constitutive Models of Biological Soft Tissues
Authors: Gardiner John C. , Weiss Jeffrey A.
Published: January 2022

Biological soft tissues are constructed of varying amounts of collagen and elastin fibers embedded in a ground substance matrix holding large amounts of trapped water. This microstructure imparts complicated material behavior to these tissues. Biological soft tissues are anisotropic, nearly incompressible, viscoelastic, nonlinear, inhomogeneous, and undergo large deformations. This combination of properties makes accurate modeling of their behavior a challenge.
Application of a Fiber-Reinforced Continuum Theory to Multiple Deformations of the Annulus Fibrosus
Authors: Klisch Stephen M. , Lotz Jeffrey C.
Published: January 2022

We applied a fiber-reinforced continuum theory to multiple experimental deformations of annulus fibrosus. Both separate and simultaneous regressions were performed while including the traction-free boundary conditions from tensile experiments.
Predicting Biaxial Behavior of the Soft Tissues Using Uniaxial Tensile Tests
Authors: Taban Faruk , Luo Shen-Yi , Evrensel Cahit A. , Mitra Aniruddha
Published: January 2022

The stress-strain curves of the fabric flexible composites and the soft tissues under various biaxial loads appear to be similar. They all contain curved fibers in soft matrices. Because of the curved fibers, inhomogeneous deformation occurs within the material. Most researchers believe that the uniaxial data cannot be used to characterize multiaxial behavior of the soft tissues in general. The constitutive equation obtained using data regression method usually gives a good description of the stress-strain behavior for the homogeneous material. It gives no physical meaning of these input values obtained for the soft tissues. Thus, these constitutive relations are highly dependent on the experimental procedure and cannot be generalized.
Strain Distribution and Relaxation Behaviour of Rat Spinal Cord
Authors: Fiford Rodney J. , Bilston Lynne E.
Published: January 2022

Uniaxial testing of rat spinal cord was performed to investigate the viscoelastic behaviour of spinal cord in tension. Stress relaxation and stress-strain data is presented, and strain distribution within the material is investigated using video analysis and surface markings.
Tensile Properties of Bovine Proximal Tibial Growth Plate Cartilage
Authors: Williams John L. , Do Pat D. , Schmidt Thomas L.
Published: January 2022

Seventy-one microtensile samples of bone-cartilage-bone from the lateral, central and medial portions of the proximal tibial growth plate were tested to failure at three speeds. Tensile strength, toe modulus, tangent modulus, and strain energy density varied by both location and strain rate, being stronger and stiffer on the lateral side and at higher strain rates. No differences could be detected in the ultimate strains by either region or strain rate.