bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of swaddling and heel warming on pain response to heel stick in neonates: a randomised control trial
Authors: Shu Shao‐Hui , Lee Ying‐Li , Hayter Mark , Wang Ruey‐Hsia
Published: January 2014

Aims and objectives

To determine the efficacy of swaddling and heel warming on pain response in neonates following heel stick.

Background

Swaddling has been suggested to reduce pain response in neonates during heel stick. Heel warming is also often performed for drawing blood easily before heel stick. However, the efficacy of both on pain response is unclear.

Design

A randomised controlled study was used.

Methods

Twenty‐five neonates were randomly assigned to each of the control, swaddling and heel‐warming groups. Heart rate, oxygen saturation Neonatal Infant Pain Scale and duration of crying were used to assess pain reactivity and pain recovery. A greater heart rate and Neonatal Infant Pain Scale increase, or oxygen saturation decrease, indicated higher pain reactivity. A longer duration of heart rate and oxygen saturation changes after heel stick back to baseline indicated a longer pain recovery.

Results

The decrease in oxygen saturation in swaddling group was significantly greater than that in heel‐warming group. The increase in the Neonatal Infant Pain Scale in control group was significantly higher than that in swaddling group. The heart rate recovery time in control group and swaddling group was significantly longer than that in heel‐warming group. The oxygen saturation recovery time in control group was significantly longer than that in heel‐warming group. The duration of crying in control group was significantly longer than those in swaddling group and heel‐warming group.

Conclusion

Both swaddling and heel warming decreased the pain response of neonates during heel stick. Heel warming resulted in a lower pain response than did swaddling for neonates, particularly in terms of pain recovery.

Relevance to clinical practice

Heel warming could become a routine practice to decrease the pain response of neonates during heel stick.
Prehospital emergency care for patients with suspected hip fractures after falling – older patients' experiences
Authors: Aronsson Kenneth , Björkdahl Ida , Wireklint Sundström Birgitta
Published: January 2014

Aims and objectives

To describe and explain older patients' lived experiences of prehospital emergency care in cases of suspected hip fractures after falling.

Background

Falls among the elderly is an issue internationally and a public health problem that seems to be on the increase. In the emergency medical services, older people are frequent patients after having suffered a fall, but there is little information on how older patients experience prehospital emergency care in cases of suspected hip fractures after falling.

Design

Qualitative interview study.

Methods

Ten older patients were interviewed. These depth interviews were tape‐recorded, transcribed verbatim and analysed for meanings.

Results

The comprehensive understanding of the phenomenon is: ‘Glad to have been rescued, despite bad experiences as well as good'. The older patient is offered care in an open and friendly atmosphere concurrently with feeling anxiety about the treatment. Intervention with streamlined care and treatment can thus simultaneously be beneficial as well as doing harm. Patients experience confusion and the need to ask questions about what really happened in the ambulance. Bad experiences remain unexplained. These findings are based on three themes with relevant subthemes: efficiency, concerned encounters and suffering from care.

Conclusions

Our study shows that prehospital emergency care when hip fracture is suspected – from patients' point of view – is insufficient and unsatisfying. Prehospital emergency care for these vulnerable patients could be improved through more compassion being shown towards older patients' existential needs and their increased participation. Furthermore, alternative methods of prehospital pain relief need to be developed.

Relevance to clinical practice

Responsibility for patients' safety regarding pain relief is emphasised. Pain relief in the emergency medical services should be individualised. This development should focus on care that is already good and gradually eradicate compassionless care.
Nursing personnel's attitudes towards fever and antipyresis of adult patients: cross‐sectional survey
Authors: Kiekkas Panagiotis , Konstantinou Evangelos , Psychogiou Kalliopi‐Styliani , Tsampoula Iliana , Stefanopoulos Nikolaos , Bakalis Nick
Published: January 2014

Aims and objectives

To investigate the attitudes of nurses caring for hospitalised adult patients towards fever and antipyresis and to identify the predictors of these attitudes.

Background

Fever is a host defence mechanism, whose harmful effects are limited to specific patients. Findings about antipyretic treatment have further challenged the need for routine or aggressive fever suppression. Unfortunately, nurses continue to be fever phobic, while their attitudes towards fever and antipyresis considerably affect antipyretic practice.

Design

Prospective, cross‐sectional, multicentre survey.

Methods

A convenience sample of registered and assistant nurses employed in surgical/medical wards and intensive care units of nine Greek hospitals was enrolled. The developed questionnaire included 10 multiple‐choice, knowledge‐evaluating items about fever and antipyresis, 10 Likert‐type attitude‐evaluating items towards fever and 10 towards antipyresis. Multiple linear regression analysis was used to identify the predictors of attitudes towards fever and antipyresis.

Results

The attitudes of the 458 participants were found to be relatively positive towards both fever and antipyresis. Lower fever/antipyresis knowledge score predicted both negative attitude towards fever (p = 0·001) and positive attitude towards antipyresis (p < 0·001), while longer professional experience predicted positive attitude towards antipyresis (p = 0·002).

Conclusions

Advancing nurses' evidence‐based knowledge about fever and antipyresis is expected to limit their tendency to overtreat fever and favour fever care based on the assessment of actual patient demands.

Relevance to clinical practice

These findings highlight the need for continuing education programmes to eliminate fever phobia and improve nurses' competency for individualised fever care.
Salt tolerance and polyphyly in the cyanobacterium Chroococcidiopsis (Pleurocapsales)
Authors: Cumbers John , Rothschild Lynn J.
Published: January 2014

Chroococcidiopsis Geitler (Geitler 1933) is a genus of cyanobacteria containing desiccation and radiation resistant strains. Members of the genus live in habitats ranging from hot and cold deserts to fresh and saltwater environments. Morphology and cell division pattern have historically been used to define the genus. To better understand the evolution and ability of the Chroococcidiopsis genus to survive in diverse environments we investigated how salt tolerance varies among 15 strains previously isolated from different locations, and if salt tolerant strains are monophyletic to those isolated from freshwater and land environments. Four markers were sequenced from these 15 strains, the 16S rRNA, rbcL, desC1, and gltX genes. Phylogenetic trees were generated which identified a distinct clade of salt‐tolerant strains. This study demonstrates that the genus is polyphyletic based on saltwater and freshwater phenotypes. To understand the resistance to salt in more details, the strains were grown on a range of sea salt concentrations which demonstrated that the freshwater strains were salt‐intolerant whilst the saltwater strains required salt for growth. This study shows an increased resolution of the phylogeny of Chroococcidiopsis and provides further evidence that the genus is polyphyletic and should be reclassified to improve clarity in the literature.
ON‐LINE MONITORING OF POLLUTION CONCENTRATIONS WITH AUTOREGRESSIVE MOVING AVERAGE TIME SERIES
Authors: Dienes Christopher , Aue Alexander
Published: January 2014

The concentration of aerosol particles, largely caused by traffic volume and often enhanced during temperature inversion episodes in the cold season, can be a concern for human health in the urban environment. This particulate matter is typically recorded as PM10, the total mass of particles below 10  μm in diameter. It is suspected that, within the PM10 class, ultrafine particles ( < 100 nm) may be responsible for causing respiratory and cardiovascular diseases. Because of their low mass, ultrafine particles are hard to detect, and researchers try to utilize PM10 in combination with nitrogen oxides NOx and other trace gases to monitor their dynamic evolution. To meet pollution standards set by national government and European Union regulation, the city of Klagenfurt, Austria, began using calcium magnesium acetate as a deicer on 11 January 2012, hoping to literally glue pollutants to the ground and thereby reducing pollution concentrations. With the statistical methodology developed in this article, the dynamic evolution of PM10 and NOx is traced for the time period starting 4 January and ending 25 January 2012, and a change in dynamics is found. The findings are based on on‐line monitoring procedures that sequentially detect structural breaks in the mean and the parameter values of an autoregressive moving average process. These are defined in terms of model residuals and one‐step ahead predictors. Theoretical properties are studied, and a simulation study shows that the proposed procedures work well in finite samples.
Rapid genetic adaptation precedes the spread of an exotic plant species
Authors: Vandepitte Katrien , de Meyer Tim , Helsen Kenny , van Acker Kasper , Roldán‐Ruiz Isabel , Mergeay Joachim , Honnay Olivier
Published: January 2014

Human activities have increasingly introduced plant species far outside their native ranges under environmental conditions that can strongly differ from those originally met. Therefore, before spreading, and potentially causing ecological and economical damage, non‐native species may rapidly evolve. Evidence of genetically based adaptation during the process of becoming invasive is very scant, however, which is due to the lack of knowledge regarding the historical genetic makeup of the introduced populations and the lack of genomic resources. Capitalizing on the availability of old non‐native herbarium specimens, we examined frequency shifts in genic SNPs of the Pyrenean Rocket (Sisymbrium austriacum subsp. chrysanthum), comparing the (i) native, (ii) currently spreading non‐native and (iii) historically introduced gene pool. Results show strong divergence in flowering time genes during the establishment phase, indicating that rapid genetic adaptation preceded the spread of this species and possibly assisted in overcoming environmental constraints.
Intestinal helminth fauna of striped dolphins (Stenella coeruleoalba) in the western Mediterranean: No effects of host body length, age and sex
Authors: Mateu Paula , Raga Juan Antonio , Fernández Mercedes , Aznar Francisco Javier
Published: January 2014

The intestine of 52 (28 males and 24 females) striped dolphins (Stenella coeruleoalba) from western Mediterranean waters was examined for helminths. Animals were found stranded along the Spanish coasts during the morbillivirus epizootic in 1990. In accordance with observations from other pelagic tetrapods, including cetaceans from other geographical regions, the intestinal helminth community was depauperate. Four helminth species were found: three tetrabothriid cestodes, Tetrabothrius forsteri (prevalence: 96.2%; mean intensity [95% CI]: 47.4 [34.4–68.2]), Trigonocotyle globicephalae (9.6%; 1.8 [1.0–2.2]), and Strobilocephalus triangularis (23.1%; 5.3 [2.9–10.2]), and immature individuals of the acanthocephalan Bolbosoma vasculosum (51.9%; 2.7 [2.0–3.4]). Schluter's variance test indicated a weak, but statistically significant association of occurrence of helminth species in dolphins, suggesting that some tetrabothriid species might use the same intermediate or paratenic hosts. Neither the abundance of helminth species nor infracommunity descriptors were significantly affected by sex, host body length or age. The absence of predictable effects of body size and age on the recruitment rate of helminths could be related to the fact that the host sample was largely composed of adults. This study provides quantitative evidence about helminth community structure of striped dolphins, based on a large sample size.
DEMOCRATIC ACCOUNTABILITY IN PUBLIC–PRIVATE PARTNERSHIPS: THE CURIOUS CASE OF FLEMISH SCHOOL INFRASTRUCTURE
Authors: WILLEMS TOM
Published: January 2014

This article questions the negative outlook on the democratic accountability in public–private partnerships (PPPs). It challenges this widely held perception in the literature with the empirical findings of a case study of Flemish school infrastructure (Belgium). A large design, build, finance, and maintenance (DBFM) programme is compared with the regular subsidizing system through the public agency AGIOn (Agency for School Infrastructure). This case study demonstrates that more accountability forums and actors can be active in the PPP, that they can behave more actively in the PPP, and that they get results in terms of accountability. It provides a critical example of having more accountability in the PPP variant of school infrastructure than in direct public provision, and there are reasons to argue that this also means improved accountability, because internal and latent processes of accountability become external and actual ones.
Host‐induced post‐transcriptional hairpin RNA‐mediated gene silencing of vital fungal genes confers efficient resistance against Fusarium wilt in banana
Authors: Ghag Siddhesh B. , Shekhawat Upendra K. S. , Ganapathi Thumballi R.
Published: January 2014

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is among the most destructive diseases of banana (Musa spp.). Because no credible control measures are available, development of resistant cultivars through genetic engineering is the only option. We investigated whether intron hairpin RNA (ihpRNA)‐mediated expression of small interfering RNAs (siRNAs) targeted against vital fungal genes (velvet and Fusarium transcription factor 1) in transgenic banana could achieve effective resistance against Foc. Partial sequences of these two genes were assembled as ihpRNAs in suitable binary vectors (ihpRNA‐VEL and ihpRNA‐FTF1) and transformed into embryogenic cell suspensions of banana cv. Rasthali by Agrobacterium‐mediated genetic transformation. Eleven transformed lines derived from ihpRNA‐VEL and twelve lines derived from ihpRNA‐FTF1 were found to be free of external and internal symptoms of Foc after 6‐week‐long greenhouse bioassays. The five selected transgenic lines for each construct continued to resist Foc at 8 months postinoculation. Presence of specific siRNAs derived from the two ihpRNAs in transgenic banana plants was confirmed by Northern blotting and Illumina sequencing of small RNAs derived from the transgenic banana plants. The present study represents an important effort in proving that host‐induced post‐transcriptional ihpRNA‐mediated gene silencing of vital fungal genes can confer efficient resistance against debilitating pathogens in crop plants.
Prevalence and Risk Factors of Atopic Eczema in Turkish Adolescents
Authors: Akcay Ahmet , Tamay Zeynep , Ergin Ahmet , Guler Nermin
Published: January 2014

Atopic eczema (AE) is the most common childhood inflammatory skin condition. The aim of this study was to evaluate the prevalence of AE and its relation to various risk factors. In a cross‐sectional study, 9,991 children ages 13 to 14 years in 61 primary schools in 32 districts of Istanbul were evaluated. The prevalence of AE and associated symptoms was assessed using the International Study of Asthma and Allergies in Childhood protocol. The relationship between risk factors and AE was evaluated using multivariate logistic regression analysis. Ten thousand nine hundred eighty‐four questionnaires were distributed to 13‐ and 14‐year‐old children in 61 schools in 32 districts of Istanbul, 9,991 of which were suitable for analysis, for an overall response rate of 91.7%. There were 4,746 boys (47.9%) and 5,166 girls (52.1%) (M/F ratio 0.920). The rates of itchy rash ever, 12‐month itchy rash, and doctor‐diagnosed AE ever were 18.2%, 12.0%, and 2.8%, respectively. The difference between rates for itchy rash ever, 12‐month itchy rash and doctor‐diagnosed AE was high (12.8–31.3, 5.8–24.8, and 0–17.2, respectively) between the districts of Istanbul. Female sex, AE family history, watching television more than 5 hours a day, region of the district, and tonsillectomy history were found to be significantly associated with doctor‐diagnosed AE at p < 0.05 in multivariate analysis. This study found a low prevalence of doctor‐diagnosed AE and related symptoms in Istanbul. Several risk factors were found to be associated with doctor‐diagnosed AE.
The Role of Microsite Conditions in Restoring Trembling Aspen (Populus tremuloides Michx) from Seed
Authors: Schott Kaitlin M. , Karst Justine , Landhäusser Simon M.
Published: January 2014

Encouraging natural regeneration of Populus tremuloides Michx (trembling aspen) from seed is a largely unexplored means for reintroducing the species into reclamation areas. We evaluated the effects of microsite (surface contour and substrate type) on aspen seedling establishment and growth on a reclaimed coal mine. The 4.6 ha study site was divided into six 48 m‐wide strips that had 15 or 40 cm capping material salvaged from a nearby forest floor added to the mine surface. We surveyed 126 m long transects located in the center of each strip for microsite conditions, and the presence and height of aspen seedlings. We found that aspen seedlings generally preferred mineral‐organic substrates and concave microsites. To facilitate the regeneration of aspen by seed, we suggest that land managers increase small‐scale roughness and microtopographic diversity on reclaimed sites.
Molluscan Community Recovery in a New England Back‐Barrier Salt Marsh Lagoon 10 Years after Partial Restoration
Authors: Thiet Rachel K. , Kidd Erica , Wennemer Jodie M. , Smith Stephen M.
Published: January 2014

Like many Eastern U.S. salt marshes, East Harbor salt marsh lagoon on Cape Cod was isolated from tidal flow in the 1800s, resulting in near‐freshwater conditions and loss of native salt marsh species. After its partial restoration in 2002, a variety of marine and estuarine fauna recolonized East Harbor, and soft shell clam (Mya arenaria) recolonization was particularly prolific. The goal of our study was to evaluate molluscan community composition, density, and distribution at regular intervals for 10 years following restoration, and to relate molluscan community recovery to various physical properties at the site. In 2007, 2008, and 2011, we sampled mollusks at several points across East Harbor, and we also recorded water salinity and temperature, particle size distribution, and submerged aquatic vegetation density. In 2007 and 2008, we encountered 12 and 11 mollusk species, respectively; M. arenaria was the most abundant species in 2007 and the second most abundant species in 2008. In 2011, we encountered eight mollusk species and M. arenaria was the most abundant species. Mollusk species richness declined from 12 to 8 species between 2008 and 2011. Our results show that mollusk species richness and density have declined significantly since the first few years following restoration; related studies attribute this to high summer water temperatures in the Main Lagoon and severe macroalgal blooms during 2005–2006. This suggests that East Harbor is still equilibrating to baseline conditions and that full tidal restoration may be necessary to sustain a diverse mollusk community at East Harbor.
50th Anniversary Article: Review on Interface Fracture and Delamination of Composites
Authors: Banks‐Sills L.
Published: January 2014

In this review paper, a methodology for measuring the interface fracture toughness of a crack between two isotropic, homogeneous materials and a delamination between two laminae of unidirectional composite materials of differing directions is presented. Four cases are considered. Two isotropic material pairs are described: glass/epoxy and two ceramic clays. Similar studies are presented for two cross‐ply laminates: 0°/90° and +45°/−45. The Brazilian disk specimen was used to carry out mixed mode fracture tests. The load and crack or delamination length at fracture were measured and used in a finite element analysis to determine the displacement field. An interaction energy orM‐integral was used to obtain the stress intensity factors at failure. These in turn were employed to calculate the critical interface energy release rateand two phase anglesψandφ, which measure the mode mixity. For theM‐integral and for each interface crack or delamination, the first term of the asymptotic solution of the fields is required. For two isotropic materials, these solutions are well known. For the laminates described here, they were determined by the Stroh and Lekhnittski formalisms. A failure criterion determined from first principles is presented. The values of,ψandφare used to specify the criterion for each material pair. A statistical analysis is presented, which predicts a 5% probability of failure.
Quantum Cognition: Key Issues and Discussion
Authors: Busemeyer Jerome R. , Wang Zheng
Published: January 2014

Quantum cognition is an emerging field that uses mathematical principles of quantum theory to help formalize and understand cognitive systems and processes. The topic on the potential of using quantum theory to build models of cognition (Volume 5, issue 4) introduces and synthesizes its new development through an introduction and six core articles. The current issue presents 14 commentaries on the core articles. Five key issues surface, some of which are interestingly controversial and debatable as expected for a new emerging field.
Simplified Model for Prediction of Bubble Growth at Nucleation Site in Microchannels
Authors: Kadam Sambhaji T. , Baghel Kuldeep , Kumar Ritunesh
Published: January 2014

Formation of the first bubble at nucleation site is an inception of the two phase flow in pool boiling and flow boiling. Bubble dynamics (bubble nucleation, growth, and departure) plays an important role in heat transfer and pressure drop characteristics during two phase flow in microchannels. In this paper, a simplified model has been developed for predicting bubble growth rate at nucleation cavity in microchannel. It is assumed that heat supplied at nucleation site is divided between the liquid phase and the vapor phase as per instantaneous void fraction value. The energy consumed by the vapor phase is utilized in bubble growth and overcoming resistive effects; surface tension, inertia, shear, gravity, and change in momentum due to evaporation. Proposed model shows a good agreement with available experimental works. In addition, the bubble waiting time phenomenon for flow boiling is also addressed using proposed model. Waiting time predicted by the model is also close to that obtained from experimental data.
Reheat Air-Brayton Combined Cycle Power Conversion Off-Nominal and Transient Performance
Authors: Andreades Charalampos , Dempsey Lindsay , Peterson Per F.
Published: January 2014

Because molten fluoride salts can deliver heat at temperatures above 600 °C, they can be used to couple nuclear and concentrating solar power heat sources to reheat air combined cycles (RACC). With the open-air configuration used in RACC power conversion, the ability to also inject natural gas or other fuel to boost power at times of high demand provides the electric grid with contingency and flexible capacity while also increasing revenues for the operator. This combination provides several distinct benefits over conventional stand-alone nuclear power plants and natural gas combined cycle and peaking plants. A companion paper discusses the necessary modifications and issues for coupling an external heat source to a conventional gas turbine and provides two baseline designs (derived from the GE 7FB and Alstom GT24). This paper discusses off-nominal operation, transient response, and start-up and shutdown using the GE 7FB gas turbine as the reference design.
Osmotic or Chemical Activation of the TRPV4 Ion Channel Enhances the Development of Chondrocyte-Based Tissue Engineered Cartilage
Authors: O’Conor Christopher J. , Benefield Halei C. , Liedtke Wolfgang , Guilak Farshid
Published: January 2014

Dynamic mechanical loading can enhance the formation of engineered cartilage, potentially through secondary biophysical effects such as changes in interstitial osmolarity. This study examined the effects of daily osmotic loading, as well as direct activation of the osmosensitive ion channel TRPV4, on the biochemical and functional properties of chondrocyte-laden cartilage constructs. Osmotic loading, as well as exposure to the TRPV4-specific agonist GSK1016790A, enhanced extracellular matrix (ECM) accumulation, and TRPV4 activation enhanced the functional properties of the constructs. This study implicates the Ca ++-permeable TRPV4 ion channel in the metabolic response of articular chondrocytes to osmotic and mechanical loading. Furthermore, these results suggest that targeting TRPV4, either directly with channel agonists, or indirectly via osmotic loading, may provide a novel strategy for enhancing tissue engineered cartilage construct maturation.
Effect of Vascular Network on Conventional Cryosurgery and Nano-Cryosurgery
Authors: Yu Qianfeng , Zhao Gang , Ding Weiping , Gao Dayong
Published: January 2014

Cryosurgery is a physical therapy of tumor treatment, which is becoming more and more popular recent years due to its important clinical merit1. However, in many clinical cases, treatment by cryosurgery has high recurrence rate, especially for tumors in some internal organs, such as liver. Most of these recurrent cases are caused by the low freezing efficiency, for example, it can’t destroy all the tumor cells especially the cells in the edge of the tumor or near the vascular network during conventional cryosurgery process. In view of this, Liu et al. proposed a new surgical strategy, “nano-cryosurgery”, to enhance freezing efficiency2.
Assessment of an Exponential Scaling Relationship for Backflow Length in Brain Tissue
Authors: Orozco Alejandro , Smith Joshua H. , García José J.
Published: January 2014

Convection enhanced delivery is a protocol to deliver large volumes of drugs over localized zones of the brain for the treatment of diseases and tumors. Brain infusion experiments at higher flow rates showed backflow, in which an annular zone is formed outside the catheter and the infused drug preferentially flows toward the surface of the brain rather than through the tissue in the direction of the area targeted for delivery. The foundational model of Morrison et al. [1] considered the deformation of the tissue around the external boundary of the catheter, the axial flow in the annular gap formed around the cannula, and the radial flow from this annular region into the porous tissue in the development of an exponential correlation for backflow length L: (1)L∝Q0.6R0.8rc0.8G-0.6μ-0.2, where Q is the infusion flow rate, R is a tissue hydraulic resistance, rc is the catheter radius, G is the tissue shear modulus, and μ is the fluid viscosity. However, this formula was derived under some limiting assumptions, such as considering the solid phase of the infused tissue as a linearly elastic material under infinitesimal deformations, whereas mechanical testing has shown large deformations under physiological loadings [2, 3].
Practical Challenges in Collecting Head Impact Biomechanics Data in Real-World Scenarios via a Helmet-Based Accelerometer System
Authors: Allison Mari A. , Kang Yun Seok , Maltese Matthew R. , Bolte John H. , Arbogast Kristy B.
Published: January 2014

Recent studies have shown that mild traumatic brain injury (mTBI) can have long-term neurological consequences and may cause permanent damage to the brain [1,2]. Given estimates that millions of these injuries occur each year [3], this knowledge has created a demand for countermeasures to prevent mTBI. In order to create countermeasures, the biomechanical inputs leading to mTBI, which are still a matter of debate, must be better understood in both children and adults.
Finite Element Modeling of Mouse Cornea and Studying Formation of Spiral Patterns on Epithelium
Authors: Mohammad Nejad Talisa , Foster Craig D.
Published: January 2014

The cornea is a transparent tissue covering the front of the eye that refracts the light rays and therefore plays a great role in focusing ability of the eye (1). A slight change in the geometry of the cornea leads to a notable change in its focusing function. Therefore, the understanding of cornea mechanics is of utmost importance to better analyze the focusing ability of the eye.
Effects of Wall Distensibility on the Numerical Simulation of Arteriovenous Fistulae
Authors: McGah Patrick M. , Aliseda Alberto , Leotta Daniel F. , Beach Kirk W.
Published: January 2014

Arteriovenous fistulae are created surgically to provide an adequate access for dialysis in patients with End-Stage Renal Disease (ESRD). Producing an autogenous shunt linking an artery and a vein in the peripheral circulation bypasses the high resistance capillary bed in order to provide the necessary flow rates at sites easily accessible for dialysis. It has long been recognized that hemodynamics constitute the primary external influence on the remodeling process of anastomosed vascular tissue [1, 2]. The high flow rate, together with the exposure of the venous tissue to the high arterial pressure, leads to a rapid process of wall remodeling that may lead to a mature access or end in failure. Recent hemodynamic simulations [3, 4] have computed very high viscous wall shear stresses within dialysis access fistulae; Stresses >15 Pa have been reported. These are much higher than what is typically considered normal or homeostatic (i.e. ≈ 1–1.5 Pa). The abnormal stresses in the fistulae have been hypothesized to cause pathological venous remodeling (i.e. intimal hyperplasia) which causes stenoses and threatens fistula patency. Given the high failure rate of dialysis access sites (up to 50% require surgical revision within one year), understanding the dynamics of blood flow within the fistula is a necessary step in understanding remodeling, and ultimately, in improving clinical outcomes.
Assembly and Characterization of 3D, Vascularized Breast Cancer Tissue Mimics
Authors: Marshall Lauren , Frost Andra , Fee Tim , Berry Joel
Published: January 2014

Drug development platforms such as two-dimensional (2D) in vitro cell culture systems and in vivo animal studies do not accurately predict human in vivo effectiveness of candidate therapeutics [1]. Cell culture systems have limited similarities to primary human cells and tissues as only one cell type is employed and animal studies have a generally limited ability to recapitulate human drug response as different species have differences in metabolism, physiology, and behavior. Mike Leavitt, a former U.S. Secretary of Health and Human Services, has stated that “currently, nine out of ten experimental drugs fail in clinical studies because we cannot accurately predict how they will behave in people based on laboratory and animal studies” [2]. Therefore, this research project is focused on developing an in vitro platform to test candidate therapeutics for more efficacious predictions of human response. We have fabricated a three-dimensional (3D) breast cancer tissue volume containing a vascular network. This vascular network is necessary because current in vitro systems (e.g., rotating bioreactors, suspension of spheroids, and growth on a porous scaffold) are limited in size (1–2 mm) by their absence of micrometer-scale blood flow micro-channels that allow for oxygen and nutrient diffusion into the tissue [4]. The extracellular matrix scaffold has been developed to mimic the native extracellular matrix and includes relevant cell types (e.g., human breast cancer epithelial cells and human breast fibroblasts) along with the prefabricated vascular network (prevascularization). These systems are intended to support long-term growth, recapitulate physiological tissue function, and accurately model response to treatment. It is hypothesized that the development of reproducible tissue volumes will transform breast cancer drug development by providing reliable, cost-effective models that can more accurately predict therapeutic efficacy than current preclinical in vivo and in vitro models.
Strength of Materials Based Prediction of Critical Stresses at the Proximal Femur: Validation by Finite Element Analysis
Authors: Tsai Andrew G. , Ashworth Timothy , Akkus Ozan
Published: January 2014

A small but significant fraction of screw placement in the proximal femur for hip fractures results in iatrogenic fractures associated with the screw hole [1]. There is evidence that the failure occurs under fatigue, and it is likely that those individuals experiencing failure have greater stresses in the proximal femur as dictated by key morphometric variables, such as cortical thickness and bone size. Finite element analysis (FEA) could greatly facilitate fracture risk assessment in the presurgical phase by predicting the local stresses, however, executing FEM in a patient customized fashion would be costly, time consuming, and technically difficult for surgeons to perform.
Finite Element Simulation of Pelvic Fractures in a UAB-CIREN Crash Case of an Automotive Side Impact
Authors: Kim Young-Ho , Kim Jong-Eun , Untaroiu Costin D. , Griffin Russell , Eberhardt Alan W.
Published: January 2014

The University Hospital at the University of Alabama at Birmingham (UAB) is the only Level I Trauma Center in the state of Alabama. Roughly 3,500 patients are admitted each year from the Birmingham Regional Emergency Medical Services System (BREMSS) region, which has a population of approximately 1.3 million. The UAB Crash Injury Research Engineering Network (CIREN) Center has agreed to enroll cases and work with CIREN engineering resources to determine injury causation.
Biaxial Mechanical Testing of Porcine Sclera Using Ultrasound Speckle Tracking for Strain Measurement
Authors: Cruz-Perez Benjamin , Morris Hugh J. , Tang Junhua , Hart Richard T. , Pan Xueliang , Liu Jun
Published: January 2014

Glaucoma is a leading cause of blindness worldwide and is associated with characteristic optic nerve damage (Clark 2012). Intraocular pressure (IOP) induced deformation of the optic nerve head (ONH) and posterior sclera may be involved in the etiology of glaucomatous damage.
Patient-Specific Stented Coronary Bifurcations: Numerical Analysis of Near-Wall Quantities and the Bulk Flow
Authors: Chiastra Claudio , Morlacchi Stefano , Gallo Diego , Morbiducci Umberto , Cárdenes Rubén , Larrabide Ignacio , Frangi Alejandro F. , Dubini Gabriele , Migliavacca Francesco
Published: January 2014

The mechanisms and the causes of the in-stent restenosis process in coronary arteries are not fully understood. One of the most relevant phenomena, which seems to be associated to this process, is an altered hemodynamics in the stented wall region [1]. In vivo local measurements of velocities and their gradients in human coronary arteries are very difficult and can hardly be applied to successfully investigate the fluid dynamic field [1]. Alternatively, virtual models of blood flow in patient-specific coronary arteries allow the study of local fluid dynamics and the computation of the wall shear stress (WSS) and other quantities which can be related to the risk of restenosis.
Designing for Crosslinked UHMWPE Implants: Clinical Consequences of Stress Concentrations
Authors: Ansari Farzana , Patten Eli , Chang Jennifer , Chou Suzanne , Mehdizadeh Amir , Kury Matt , Huddleston James , Jewett Brian , Mickelson Dayne , Kim Hubert , Ries Michael , Pruitt Lisa
Published: January 2014

Ultrahigh molecular weight polyethylene (UHMWPE) remains the polymer bearing of choice for total joint replacements (TJR) [1]. However, the long-term performance of this polymer has been limited by in vivo wear: UHMWPE wear debris generated in the joint space can travel into the periprosthetic bone, initiating osteolysis and implant loosening [2]. Crosslinked UHMWPE (through ionizing radiation) has demonstrated increased wear resistance [3], but at the cost of reduced fatigue crack propagation and fracture resistance [4]. Additionally, radiation processes can release free radicals which, when not eliminated through thermal treatment, can increase UHMWPE susceptibility to oxidation and mechanical embrittlement [5]. Such tradeoffs present clinical concerns when implant designs incorporate stress concentrations that experience elevated stresses under loading. These compromises are evaluated through the failure analysis of several crosslinked UHMWPE retrievals that fractured in vivo.
Extending the Useable Range of Active Orthotic Exoskeletons by Recapture of Walking Energy
Authors: Fisher Keith B.
Published: January 2014

Most people don’t think twice about the energy required for walking, except when interested in burning calories during exercise. However, someone needing to depend on active orthotics, or prosthetics, due to partial paralysis or other weakness of the lower extremities, would find energy efficiency of great interest if it meant the range of use was limited by the energy required to power the assistive devices.
A High Fidelity, Micro-Structural and Anatomically Accurate 3D Finite Element Model for Functioning Heart Mitral Valve
Authors: Lee Chung-Hao , Oomen Pim J. A. , Rabbah Jean Pierre , Saikrishnan Neela , Yoganathan Ajit , Gorman Robert C. , Gorman Joseph H. , Sacks Michael S. , Amini Rouzebeh
Published: January 2014

Many surgeons have come to view mitral valve (MV) repair as the treatment of choice in patients with mitral regurgitation (MR) [1]. However, recent long-term studies have indicated that the recurrence of significant MR after repair may be much higher than previously believed, particularly in patients with (ischemic mitral regurgitation) IMR [2]. Since a significant number of these failures result from chordal, leaflet and suture line disruption, it has been suggested that excessive tissue stress and the resulting strain-induced tissue damage are important etiologic factors. We thus hypothesize that the restoration of homeostatic normal MV leaflet tissue stress levels in IMR repair techniques ultimately leads to improved repair durability through restoration of normal MV responses. Therefore, the objective of this study is to develop a novel high-fidelity and micro-anatomically accurate 3D finite element (FE) model that incorporates detailed collagen fiber architecture, realistic constitutive models, and micro-anatomically accurate valvular geometry to connect the cellular function of the MV tissues with the organ level mechanical responses, and to aid in the design of MV repair procedures.
A Novel Framework to Assess ACL Injury Risk Based on Validated Personalized Finite Element Models
Authors: Kiapour A. M. , Kiapour A. , Demetropoulos C. K. , Goel V. K.
Published: January 2014

The anterior cruciate ligament (ACL) is one of the most frequently injured ligaments of the knee, with a prevalence estimated to be 1 in 3000 in the U.S. population. Current approaches to biomechanical finite element (FE) modeling of the knee are at a crossroads. While the ideal scenario for clinically applicable FE modeling would be a subject-specific approach with detailed, image-based anatomic reconstruction of the joint, the computational intensity of such an approach would almost certainly preclude its clinical applicability. The assumption that an accurate assessment of an individual’s ACL injury risk profile can be attained through generalized FE models also has yet to be tested. The current study aims to test a novel framework in which the developed, validated generic FE model will be customized to each specimen based on quantified ACL structural properties (mechanical and anatomical). We hypothesized that personalized FE models using the proposed framework will result in more accurate predictions of ACL strain (as an established measure of injury risk) compared to the generic FE model. Thus, these models may serve as individual-based injury risk assessment tools.
Relationship Between Meniscal Sample Swelling and the Compressive Properties of Bovine Menisci
Authors: Andrews Stephen H. J. , Shrive Nigel G. , Ronsky Janet L.
Published: January 2014

The menisci are anisotropic hydrated connective tissues, situated in the tibiofemoral joint. The menisci transmit approximately 50% of the load across this joint [1, 2]. In this tissue, compression would only be experienced in the axial (vertical) direction, and as such, many studies have tested samples in the axial direction to determine the compressive properties [3–5]. The material behaviour of the menisci has been described as biphasic, meaning the response of the tissue to applied load is time dependent and determined by both the solid constituents and their interaction with the fluid component [3]. Due to the low permeability of the tissue, deformation results in relative movement of the solid matrix and the fluid it contains, resulting in the creation of drag forces between the two phases. Fluid exudation from the matrix governs the viscoelastic behaviour of the tissue, including stress relaxation and creep [6]. The swelling behaviour of meniscal samples in varying osmotic environments was evaluated in our lab (unpublished data), where they swelled significantly, approximately 30% volumetrically in iso-osmotic phosphate buffered saline (PBS). It was hypothesized that the material properties of the tissue would be affected by this significant swelling. To date, no study has evaluated the effect of sample swelling, due to sample preparation and storage, on the behaviour of the menisci in compression. Therefore, the purpose of this study was to evaluate this relationship. We hypothesized that meniscal samples would be less stiff and more permeable in a swollen state than when they are compressed to the ‘fresh’, non-swollen, thickness prior to initiation of the protocol.
Detecting Associations Between Knee Rotational Laxity and Kinematics in a Healthy Population
Authors: Baghoolizadeh Mahta , Zabala Michael , Keiper Alison , Andriacchi Thomas
Published: January 2014

Passive knee laxity, which is determined by the soft tissues and articular structures of the knee, allows for the translation and rotation of the knee 1. While laxity increases following soft tissue injury, there is a lack of clinical evidence demonstrating a relationship between increased passive laxity and subsequent clinical problems such as osteoarthritis. However, there is increasing evidence that abnormal active rotational kinematics during walking are a potential risk factor for osteoarthritis (OA) initiation and progression 2. Establishing a relationship between passive knee laxity and active knee kinematics is therefore clinically important, but at present there is a paucity of information on the interaction between passive and active knee rotational movement.
In Vivo Validation of Irreversible Electroporation Electric Field Threshold for Prostate Tissue
Authors: Neal Robert E. , Kavnoudias Helen , Rosenfeldt Franklin , Ou Ruchong , Marron James , Davalos Rafael V. , Thomson Kenneth R.
Published: January 2014

Irreversible electroporation (IRE) is a non-thermal focal ablation technique that uses needle electrodes to deliver a series of brief (100μs duration) electric pulses into the targeted region. These alter cellular transmembrane potentials, destabilizing the membranes in a manner that kills the cells while sparing major vasculature and other sensitive structures. IRE can therefore be used in regions ineligible for surgical resection or thermal ablation. Treatments result in rapid lesion creation and resolution [1], are unaffected by the blood perfusion “heat sink”, can be planned with numerical modeling [2], and its effects can be readily monitored with various imaging modalities [3]. Therapeutic ire has proven effective in the treatment of experimental [4] and clinical tumors. A human safety study attained complete regression in 46 of 69 tumors ineligible or unresponsive to conventional treatment [5], and veterinary case studies convey its utility in large difficult tumors [6, 7].
NF-κB Mediates Cartilage Degradation Induced by Trauma Injury and Interleukin-1
Authors: Kashyap Meghana , Carter Kristen T. , Sauer Brent C. , Chen Christopher T.
Published: January 2014

Chondrocyte death, induced by impact injury (necrosis) and/or apoptotic inducers such as cytokines, and high level of nitric oxide, is important for the development of post-traumatic arthritis (PTA) [1–3]. The upregulation of pro-inflammatory cytokines, such as interleukin −1 (IL-1) and Tumor necrosis factor (TNF) α, is known to mediate cartilage degradation in inflammatory diseases and after trauma injury [1,2, 6–9]. IL-1 induces the degradation of proteoglycan (PG) in cartilage through NF-κB and Mitogen-activated protein kinases (MAPK: p38, ERK and JNK) pathways [1,2,6]. IL-1 is highly upregulated in synovial joint after impact injury, but the role of IL-1 induced chondrocyte death and matrix/PG degradation in injured cartilage is not completely clear.
Targeting the Tumor-Draining Lymph Node With Adjuvant Nanoparticles for Cancer Immunotherapy
Authors: Thomas Susan N.
Published: January 2014

Immunotherapy-based approaches for cancer treatment are of increasing clinical interest. Principles of drug delivery and the emerging field of material design for immunomodulation might hold significant promise for novel approaches in cancer immunotherapy since biomaterials engineering strategies enable enhanced delivery of immune modulatory agents to tissues and cells of the immune system1. One tissue of significant clinical interest in a cancer setting is the tumor-draining lymph node (TDLN), which participates in cancer progression by enabling both metastatic dissemination as well as tumor-induced immune escape. Hence, the TDLN represents a novel target for drug delivery schemes for cancer immunotherapy. We hypothesize that targeted delivery of adjuvants (Adjs) to the TDLN using a biomaterials-based approach might promote antitumor immunity and hinder tumor growth.
Dependence of Higher Frequency Components on Bone Tissue Alterations in the Rat-Tail Model
Authors: Kim Brian , Goenka Shilpi , Peelukhana Srikara V. , Stringer Keith F. , Kim Jay H. , Banerjee Rupak K.
Published: January 2014

Through a recently conducted rat-tail vibration experiment, we have been able to determine that the tested frequencies of vibration have a significant effect on biochemical damage signified by nitro-tyrosine (NT) staining on trabecular bone, while structural damage quantified through a Hematoxylin and Eosin (H&E) stain on cortical bone exhibited statistical significance only for the 250 Hz group compared to the control group. These results seem to indicate a relationship between the growing quantities of biochemical damage when increasing the excitation frequency, thus further experimentation for frequencies between 250 Hz and 400 Hz is recommended.
Liver Perfusion Analysis Model for Transplantation Using Hybrid Computational Fluid Dynamics Model With Porous Media
Authors: Yamaguchi Takayuki , Obara Hiromichi , Matsuno Naoto , Numano Tomokazu , Sekine Norio , Enosawa Shin , Mizunuma Hiroshi
Published: January 2014

Liver has complex structure of blood vessels. There are two inlets of the blood flow in a liver. One is hepatic artery in which the blood flow from a heart to supply oxygen. Another is portal vein in which the blood flow from the digestive organs to maintain the metabolic and the detoxification processes. These vessels join at hepatic lobule which is consisted by hepatocyte. The hepatic lobule has a central vein and the central veins drain the blood flow into a hepatic vein. The hepatic vein is unique outlet of the blood flow of the liver.