bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Models of Cerebral Aneurysms Using Intravascular Hemodynamic Measurements
Authors: McGah Patrick M. , Aliseda Alberto , Levitt Michael R. , Kim Louis J.
Published: January 2014

The hemodynamic environment of intracranial aneurysms is considered an important promoter of aneurysmal formation, growth and rupture [1]. Flow-diverting stent technology [2] has been developed to reduce blood flow (and hence hemodynamic stress) inside the aneurysm, potentially lowering the rupture risk. Computational fluid dynamics (CFD) modeling of aneurysms and the surrounding cerebral vasculature allows investigators to calculate important hemodynamic characteristics such as wall shear stress (WSS), which have been implicated in aneurysm growth and rupture.
Characterizing Swelling Pressure and Hydration Relationship for Porcine Corneal Stroma
Authors: Hatami-Marbini Hamed , Etebu Ebitimi , Rahimi Abdolrasol
Published: January 2014

The mechanical properties and structure of connective tissues such as the cornea and articular cartilage are derived from the functions and properties of their extracellular matrix, which is a polyelectrolyte gel composed of collagenous fibers embedded in an aqueous matrix. The collagen fibrils in the extracellular matrix of the corneal stroma are arranged in a regular lattice structure, which is necessary for corneal transparency and transmitting the incident light to the back of the eye. This regular pseudo hexagonal arrangement is attributed to the interaction of collagen fibrils with the proteoglycans; these regularities are lost in proteoglycan knock-out mice [1]. Proteoglycans are heavily glycosylated glycoproteins consisting of a core protein to which glycosaminoglycan chains are covalently attached. The main proteoglycan in the corneal stroma is decorin. Decorin is the simplest small leucine-rich proteoglycan with only a single glycosaminoglycan side chain. It has a horse shape core protein and binds collagen fibrils at regular sites. Under normal physiological conditions, these linear carbohydrate polymers are ionized and carry negative charges due to the presence of negatively charged carboxylate and sulfate groups. The presence of these fixed charges creates an imbalance of charge density within the stroma and its surrounding aqueous domain. Therefore, the tissue has a tendency to swell when immersed in a bathing solution. In order to create mathematical models for the corneal mechanics, a proper experimental characterization of the swelling properties of the tissue is necessary.
Thermal Residual Limb Manikin to Test Novel Cooling Technologies for Prosthetic Sockets
Authors: Bates Kathleen J. , Klute Glenn K.
Published: January 2014

Heat and perspiration inside the prosthesis cause discomfort and adherence problems for lower limb amputees. To bench test new prosthetic socket interventions, we developed a thermal residual limb manikin (TRLM) and used it to compare two novel cooling technologies: (1) a vacuum pump which provides ventilation across the skin (FLOW) and (2) a liquid cooling sleeve (SLEEVE). Power to maintain TRLM core temperature was measured to indicate cooling effectiveness. Power increased by 7% and 8% after 90 minutes of convective cooling and evaporative cooling, respectively, with the FLOW system. Power increased by 28% with the SLEEVE system.
The Role of Motion Analysis in Biomedical Engineering Education and Interdisciplinary Research
Authors: Carey Stephanie L. , Lura Derek J. , Dubey Rajiv V.
Published: January 2014

The purpose of this paper is to summarize current motion analysis techniques and described their role in biomedical engineering education as well as in interdisciplinary research. At the University of South Florida (USF), various methods of motion analysis are used for collaborative research in fields such as prosthetics, robotics, rehabilitation, and injury prevention. The motion analysis laboratory is also used in course work in a variety of fields promoting interdisciplinary exchanges among students and faculty.
Interlayer Micromechanics of Semilunar Heart Valve Leaflets
Authors: Buchanan Rachel M. , Sacks Michael S.
Published: January 2014

The aortic and pulmonary semilunar heart valve leaflets (AV and PV respectively) are heterogeneous structures comprised of three distinct tissue layers. All three layers contain varying amounts of collagen, elastin and glycosaminoglycans (GAGs). The fibrosa layer is an undulated structure that faces the aorta comprised primarily of Type 1 collagen highly aligned in the circumferential direction. On the opposite face of the valve is the ventricularis layer that is populated with an organized elastin network. The spongiosa layer resides between the fibrosa and ventricularis and is rich in GAGs. All three layers work in unison at the tissue level to produce effective leaflet mechanical behavior. While the mechanical behavior of the fibrosa and ventricularis layers have been well studied [1], little information exists on the effective mechanical behavior of the GAG rich spongiosa layer.
Racial Differences in the Aging Human Sclera
Authors: Grytz Rafael , Fazio Massimo A. , Libertiaux Vincent , Bruno Luigi , Gardiner Stuart , Girkin Christopher A. , Downs J. Crawford
Published: January 2014

Glaucoma is a leading cause of blindness in the world and is due to the damage of retinal ganglion cell axons. While an abnormally high intraocular pressure (IOP) is the most relevant risk factor for glaucomatous damage, the elderly and persons of African ancestry have a significantly greater tendency for developing glaucoma than younger people and those of European ancestry.
Nycthemeral Rhythm of the Frequency and Biomechanical Energy of High Frequency Intraocular Pressure Fluctuations
Authors: Libertiaux Vincent , Seigfreid William P. , Fazio Massimo A. , Reynaud Juan F. , Burgoyne Claude F. , Downs J. Crawford
Published: January 2014

The optic nerve head (ONH) is the site of insult in glaucoma, the second leading cause of blindness worldwide. Intraocular pressure (IOP) is commonly regarded as a major factor in the onset and progression of the disease1 and lowering IOP is the only clinical treatment that has been shown to retard the onset and progression of glaucoma2. However, many patients continue to progress even at an epidemiologically-determined normal level of IOP3. This suggests that in addition to the mean value of IOP, IOP fluctuations could be a factor in glaucomatous pathophysiology. The importance of low frequency fluctuations of clinically-measured mean IOP remains controversial. These studies all rely on snapshot measurements of mean IOP at each time point, and those measurements are taken at relatively infrequent intervals (hourly at the most frequent, but usually monthly or longer). Recently however, there has been some interest in ocular pulse amplitude, or the fluctuation in IOP associated with the cardiac cycle, which can be measured by Dynamic Contour Tonometry (DCT). DCT provides continuous measurement of IOP, but only for a period of tens of seconds in which a patient can tolerate corneal contact without blinking or eye movement, which ironically are two of the most common sources of large high frequency IOP fluctuations according to our telemetric data collected from monkeys4 and previous human studies. In a recent report, continuous IOP telemetry was used in three nonhuman primates to characterize IOP dynamics at multiple time scales for multiple 24-hour periods5.
Novel Tissue-Engineered Heart Valve
Authors: Syedain Zeeshan , Meier Lee , Reimer Jay , Tranquillo Robert
Published: January 2014

Tissue-engineered heart valves (TEHV) have the potential to revolutionize valve replacements therapies, especially for pediatric patients. While much progress has been made toward implanting a TEHV, a major limitation to date has been in vivo leaflet retraction due to the contractile nature of the cells transplanted within the TEHV. This phenomenon has been problematic in numerous studies, particularly for approaches employing the use of a fibrin scaffold (Syedain et al. 2011, Flanagan et al. 2009). Additional challenges in the development of a TEHV include designing a 3D mold that allows for proper coaptation and functionality of engineered leaflets. Herein, we present a novel approach for developing a TEHV from a decellularized engineered tube fabricated from fibrin that is remodeled by entrapped dermal fibroblasts, and matured using a custom pulse flow-stretch bioreactor. This approach has the potential to deliver an off-the-shelf engineered heart valve that exhibits the ability to be readily recellularized in contrast to current clinically employed tissue-based valve replacements.
Spaceflight Related Changes in Structure and Strength of Mouse Trabecular and Cortical Bone From the STS-118 Space Shuttle Mission
Authors: Ortega A. M. , Bateman T. A. , Livingston E. W. , Paietta R. C. , Gonzalez S. M. , Stodieck L. S. , Ferguson V. L.
Published: January 2014

Rapid bone loss during spaceflight is a well-established and continuing medical issue for astronauts. It has been reported that astronauts have displayed bone loss at rates of up to 2.7%/month in weight-bearing bones, or about 6 times that of post-menopausal women [1]. Rodent models have provided a means to further our understanding of the effects of microgravity on bone quality, both from studies in which rodents have flown aboard space missions and those in which weightlessness is simulated on earth through musculoskeletal unloading [2]. Such studies have the potential to not only further our understanding of the cause of decreased bone integrity in space, but also provide an accelerated model for the study of osteo-degenerative diseases affecting the general public, leading to improved treatment methods for both spaceflight and age or illness related osteoporosis.
Green Machine: Electric Yard and Garden Helper
Authors: Grenis Taylor , Hutchings Brian , Sorenson Kolby , Van Horssen Bryan , Williams Clay , De Vries Kenneth Larry , Merryweather Andrew
Published: January 2014

The mean age in the population is rising and the number of individuals age 65 and older is projected to increase prompting the need for technology to aid persons with decreased strength and physical ability 1. Gardening is a form of moderate-intensity aerobic workout, which burns calories and helps maintain flexibility. It has also been shown to be therapeutic and fulfilling. The purpose of the Green Machine is to provide a robotic gardening/yard work assistant to aid with transporting and handling heavy loads during yard and garden work.
Variability in Mechanical Properties of Insect Tracheal Tubes
Authors: Becker Winston R. , Webster Matthew R. , De Vita Raffaella
Published: January 2014

Insects employ a network of tracheal tubes to transport oxygen directly to every cell of the body. During respiration, these tubes undergo localized and rhythmic deformations due to local variation in their structural and mechanical properties. In order to elucidate the mechanisms of insect respiration, mechanical tests on ring sections of tracheal tubes extracted from American Cockroaches were conducted. A total of 33 specimens collected from 14 tracheal tubes located in the upper thorax of the insects were successfully tested. The ultimate tensile strength (22.6 ± 13.3 MPa), ultimate strain (1.57 ± 0.68 %), elastic modulus (1740 ± 840 MPa), and toughness (0.175 ± 0.156 MJm −3) were measured in the radial direction. The mechanical properties of ring sections excised from the same tracheal tube were shown to exhibit less variability than those of ring sections excised from different tracheal tubes. The results of this study will help in determining the relationship between the mechanics and structure of tracheal tube thus ultimately leading to the creation of novel bio-inspired micro-systems.
Multiscale Experimental and Computational Investigation of Cortical Bone Fracture
Authors: Feerick E. M. , McGarry J. P.
Published: January 2014

Previous experimental studies of cortical bone have investigated cortical bone fracture toughness and crack trajectory as a function of microstructural alignment of osteons [1,2]. The dependence of osteon orientation on screw pullout force and crack propagation trajectory during screw pullout has been demonstrated previously by Feerick and McGarry (2012) [3]. The alternate failure modes for longitudinal and transverse screw pullout observed in the latter study are shown in Figure 1. Using an isotropic damage criterion with crack growth was simulated using an element deletion technique. An explicit representation of cortical bone microstructure was required to replicate experimental observations. The use of such a computational scheme for 3D macro-scale applications is not viable given the requirement of explicit representation of the microstructure. Other computational studies of cortical bone have also developed geometric representations of the microstructure of cortical bone to simulate the fracture and establish crack trajectories [4]. Again, upscaling these detailed microstructural geometries in 3D macroscale simulations of fracture would currently be computationally unfeasible.
Adapting the Cassini Curve to Approximate
In Vivo Irreversible Electroporation Ablations in Porcine Liver
Authors: Garcia Paulo A. , Arena Christopher B. , Neal Robert E. , Goldberg S. Nahum , Ben-David Eliel , Davalos Rafael V.
Published: January 2014

Irreversible electroporation (IRE) is a new minimally invasive non-thermal focal ablation technique that has been used for the treatment of spontaneous tumors in canine and human patients [1, 2]. The procedure typically involves placing two electrodes into or around a tumor and delivering a series of low energy electric pulses to kill tumor tissue with sub-millimeter resolution. The pulses generate an electric field that alters the resting transmembrane potential (TMP) of the cells. Depending on the magnitude of the induced TMP, the electric pulses can have no effect, reversibly increase membrane permeability, or cause cell death in the case of IRE.
Calcium Regulation in Lymphatic Endothelial Cells Under Flow
Authors: Jafarnejad Mohammad , Cromer Walter E. , Kaunas Roland R. , Zawieja David C. , Moore James E.
Published: January 2014

The lymphatic system collects interstitial fluid and proteins and pumps them back to the blood circulatory system. Additionally, it is important in lipid uptake in the mesentery and immune response. Any failure of the system in pumping lymph results in swelling of tissue and/or organ(s), or lymphedema. The lymphatic system consists of initial lymphatic capillaries and larger collecting vessels. The latter contain tubular regions covered with contracting lymphatic muscle cells, which are separated by bi-leaflet valves to ensure unidirectional flow [1].
Microdevice for Delivering Homogeneous Equi-Biaxial Strain to Live Cells Without the Use of Platen Structures
Authors: Wang Qian , Zhao Yi
Published: January 2014

Live cells from most of the membranous tissues such as alveoli are subjected to equi-biaxial strain originated from their extracellular environments. To understand the role of equi-biaxial strain in live cells, a number of engineered methods have been developed for applying such mechanical strain to in vitro cultured cells. Among these methods, deforming a flexible substrate on a circular platen has been widely used [1], and has been miniaturized into millimeter scale for parallel stretching assay (Figure 1a). Nonetheless, the strain homogeneity becomes increasingly challenging at smaller scale, since it requires an ultra-thin membrane, an indentation platen with well controlled dimension, and the highly precise alignment. This obviously increases the fabrication and operation complexities. Devices that deliver homogeneous strain with minimal fabrication and assembling complexities are needed.
Development of a Pediatric Forearm Finite Element Model for Characterizing Mechanical Responses of Backward Fall
Authors: Cai Yun , Mao Haojie , Yang King H.
Published: January 2014

Distal radius and carpal fractures in children and adolescent account for approximately 25% of all pediatric fractures [1]. For the age distribution, 5 to 14 years olds group comprised largest proportion (26%) of all hand and forearm fractures than other age groups. Radius and/or ulna fractures took up the largest proportion of fractures (32.9%) in age group 5 to 14 years old. A population-based study revealed that the incidence rate of forearm fractures in boys and girls aged 5 to 14 years increased dramatically. In particular, the age group 10 to 14 has the highest increase in the period from 1997 to 2009 [1].
Experimental Determination of Pressure Wave Transmission to the Brain During Head-Neck Blast Tests
Authors: Ott Kyle , Voo Liming , Merkle Andrew , Iwaskiw Alexander , Wickwire Alexis , Wester Brock , Armiger Robert
Published: January 2014

Traumatic Brain Injury (TBI) has been the termed the “signature injury” in wounded soldiers in recent military operations [1]. Evidence has shown a strong association between TBI and blast loading to the head due to exposure to explosive events [2, 3]. Head injury mechanisms in a primary blast environment remain elusive and are the subject of much speculation and hypotheses. However, brain injury mechanisms have traditionally been attributed to either a direct impact or a rapid head acceleration or deceleration. Extensive research has been performed regarding the effects of blunt trauma and inertial loading on head injuries [4, 5]. Direct impacts to the head can largely be described based on linear acceleration measurements that correlate to skull fracture and focal brain injuries [6]. Computational head modeling of blunt impact events has shown that the linear acceleration response correlates well with increases in brain pressure [7]. Intracranial pressure, therefore, has been one of the major quantities investigated for correlation to blast induced TBI injury mechanisms [8–14].
Effect of Curvature on Sagittal Plane Moment Arms of Human Neck Muscles
Authors: Suderman Bethany L. , Vasavada Anita N.
Published: January 2014

In musculoskeletal models of the cervical spine, muscles are often modeled as straight paths from origin to insertion [ e.g., 1]. However, muscle paths in the neck are constrained by bone and other soft tissues, and some studies have found that applying curvature to muscle paths improves anatomical accuracy [2; 3] and affects muscle parameters such as moment arm [3] and moment [4]. Currently, data available in the literature for neck muscle moment arms (MA) are sparse. In this study we estimated in-vivo moment arms using MRI-derived neck muscle paths modeled with curvature and those modeled as straight paths, for head and neck rotation in the sagittal plane (flexion-extension motion). We hypothesize that moment arm estimates for curved paths will be significantly different from estimates for straight paths.
An Instrumented Mouthguard to Measure Head Accelerations Due To Impact
Authors: Birmingham Grant , Smith Lilan , Brock Jennifer M. , Lund John , Paris Anthony J.
Published: January 2014

In the long term, quantitative measurements indicating the magnitude and nature of head impacts will be essential to understanding the biomechanics of head injury. Tools are needed that can quantitatively measure the levels of head acceleration experienced by athletes in a variety of situations in order to assess these risks. The current research is aimed at developing instrumentation that is comfortable enough to use in the field and which can measure head accelerations from blows to the head repeatably and accurately. Soccer is a unique sport in that the unprotected head is deliberately used to direct the motion of the ball during play, which makes it practical to study in a controlled laboratory setting. While the possible long-term effects of heading are still subject to debate [1,2], there is evidence which suggests that it is responsible for transient neurocognitive deficits [3] and transient concussion symptoms [4].
The Feasibility of Using Millimeter Wave Heating for Non-Invasive Measurement of Skin Blood Flow in Humans
Authors: Nelson D. A. , Leavesley S. J. , Hamlin G. T. , Downey J. M.
Published: January 2014

A non-contacting method to measure skin blood flow (SkBF) in human extremities that is both simple and accurate could be invaluable in the diagnosis and management of several clinical conditions. For excample, measurement of SkBF in the digit(s) can be useful in the diagnosis and management of Peripheral Arterial Disease, often associated with Type 2 diabetes (Petrofsky et al., 2008). Skin blood flow in the foot can be an indicator of successful infrainguinal revascularization surgery in patients with lower limb ischemia (Saucy et al., 2006; Yamada et al., 2008). Assessment of peripheral perfusion can be useful in determining hemodynamic stability of patients suffering from acute circulatory shock (Lima et al., 2009) or circulatory failure (Lima and Bakker, 2005).
Incorporating single‐side sparing in models for predicting parotid dose sparing in head and neck IMRT
Authors: Yuan Lulin , Wu Q. Jackie , Yin Fang‐Fang , Jiang Yuliang , Yoo David , Ge Yaorong
Published: January 2014

Purpose:

Sparing of single‐side parotid gland is a common practice in head‐and‐neck (HN) intensity modulated radiation therapy (IMRT) planning. It is a special case of dose sparing tradeoff between different organs‐at‐risk. The authors describe an improved mathematical model for predicting achievable dose sparing in parotid glands in HN IMRT planning that incorporates single‐side sparing considerations based on patient anatomy and learning from prior plan data.

Methods:

Among 68 HN cases analyzed retrospectively, 35 cases had physician prescribed single‐side parotid sparing preferences. The single‐side sparing model was trained with cases which had single‐side sparing preferences, while the standard model was trained with the remainder of cases. A receiver operating characteristics (ROC) analysis was performed to determine the best criterion that separates the two case groups using the physicianˈs single‐side sparing prescription as ground truth. The final predictive model (combined model) takes into account the single‐side sparing by switching between the standard and single‐side sparing models according to the single‐side sparing criterion. The models were tested with 20 additional cases. The significance of the improvement of prediction accuracy by the combined model over the standard model was evaluated using the Wilcoxon rank‐sum test.

Results:

Using the ROC analysis, the best single‐side sparing criterion is (1) the predicted median dose of one parotid is higher than 24 Gy; and (2) that of the other is higher than 7 Gy. This criterion gives a true positive rate of 0.82 and a false positive rate of 0.19, respectively. For the bilateral sparing cases, the combined and the standard models performed equally well, with the median of the prediction errors for parotid median dose being 0.34 Gy by both models (p = 0.81). For the single‐side sparing cases, the standard model overestimates the median dose by 7.8 Gy on average, while the predictions by the combined model differ from actual values by only 2.2 Gy (p = 0.005). Similarly, the sum of residues between the modeled and the actual plan DVHs is the same for the bilateral sparing cases by both models (p = 0.67), while the standard model predicts significantly higher DVHs than the combined model for the single‐side sparing cases (p = 0.01).

Conclusions:

The combined model for predicting parotid sparing that takes into account single‐side sparing improves the prediction accuracy over the previous model.
TRAIL-Blazing Therapy Against Circulating Tumor Cells
Authors: Chow Edward Kai-Hua
Published: January 2014

Nanoparticle-mediated functionalization of leukocytes is effective against circulating tumor cells.
Shiva the Destroyer: Targeting the Destruction of RNA Polymerase for Cancer Treatment
Authors: Narla Goutham
Published: January 2014

A new drug with a unique mechanism of action intercalates into GC-rich ribosomal DNA, blocking RNA polymerase I and inhibiting tumor growth.
“It’s ARAP” for Type II Diabetes
Authors: Neale Benjamin M.
Published: January 2014

Increased
ARAP1
expression is a risk factor for type II diabetes.
Breast malignancy masquerading under the cloak of acute urticaria
Authors: O'Donnell Erin , Havyer Rachel
Published: January 2014

Urticaria is a common disorder characterised by well-demarcated and intensely pruritic erythematous skin swellings. Common triggers include infection, allergic reactions or medications. While often idiopathic, the presence of urticaria can be associated with underlying systemic disease. We report a case of a patient who presented with diffuse and refractory urticaria. A thorough workup was conducted to determine the aetiology including routine age-appropriate cancer screening. Mammography revealed four lesions in the patient's left breast with biopsy consistent with invasive ductal carcinoma. Disappearance of the urticarial lesions with mastectomy suggests an association between breast malignancy and urticaria. Thus, refractory urticaria with unknown cause should prompt a thorough history, physical examination and review of age-appropriate cancer screening.
Evaluation of usefulness of myeloperoxidase index (MPXI) for differential diagnosis of systemic inflammatory response syndrome (SIRS) in the emergency department
Authors: Cha Yong Sung , Yoon Jeong Min , Jung Woo Jin , Kim Yong Won , Kim Tae Hoon , Kim Oh Hyun , Cha Kyoung Chul , Kim Hyun , Hwang Sung Oh , Lee Kang Hyun
Published: January 2014

Background

The myeloperoxidase index (MPXI) is elevated in infection. We ascertained whether MPXI might be useful in differentiation of sepsis versus non-infectious systemic inflammatory response syndrome (SIRS) in emergency department (ED).

Methods

After exclusion of patients with an age of <18 years, trauma, haematological disease and on anticancer chemotherapy, 444 consecutive cases with SIRS (sepsis: 224, 50.3%; and non-infectious SIRS: 220, 49.7%) diagnosed and treated at the ED of The Wonju Severance Christian Hospital from May 2012 to June 2012 were retrospectively reviewed.

Results

Median MPXI was higher in sepsis versus non-infectious SIRS (0.1 (IQR: −3.1 to 2.5) vs −1.2 (−4.1 to 1.6), respectively, p=0.020). Median white cell count, neutrophil percentage, C reactive protein level and δ neutrophil index were also higher. However, MPXI resulted as not statistically useful for differential diagnostic parameter in analysis.

Conclusions

MPXI is higher in sepsis than in non-infectious SIRS. However, there is currently no evidence that the MPXI adds any additional benefit to differentiate sepsis from non-infectious SIRS in the ED. Therefore, further study will be needed.
Triaging older major trauma patients in the emergency department: an observational study
Authors: Lukin William , Greenslade Jaimi H , Chu Kevin , Lang Jacelle , Brown Anthony F T
Published: January 2014

Background

The objective of this study was to compare the triage category assigned to older trauma patients with younger trauma patients upon arrival to the emergency department. The focus was to examine whether older major trauma patients were less likely to be assigned an emergency triage category on arrival to the emergency department after controlling for relevant demographics, injury characteristics and injury severity.

Methods

This was an observational study using data from the Queensland Trauma Registry. All trauma patients aged 15 years and older who presented to contributing hospitals between 1 January 2005 and 31 December 2009 with an Injury Severity Score (ISS)>15 were included. Logistic regression analysis examined the odds of assignment to emergency (Australasian Triage Scale (ATS) 1 or 2) versus urgent (ATS 3–5) treatment for patients across various age categories after adjustment for relevant demographics, injury characteristics and injury severity.

Results

The study used data on 6923 patients with a median (IQR) age of 43 (26–62) years and a mortality of 11.4% (95% CI 10.7% to 12.2%). Compared with individuals aged 15–34, the adjusted odds of being assigned an ATS category 1 or 2 were 30% lower (OR=0.68, 95% CI 0.57 to 0.81) for individuals aged 55–75 years and were 50% lower (OR=0.46, 95% CI 0.37 to 0.56) for individuals aged 75 years or older.

Conclusions

Among patients with an ISS>15, older major trauma patients were less likely to be assigned an emergency triage category compared with younger patients. This suggests that the elderly may be undertriaged and provides a potential area of study for reducing mortality and morbidity in older trauma patients.
Current practice regarding seizure prophylaxis in aneurysmal subarachnoid hemorrhage across academic centers
Authors: Dewan Michael C , Mocco J
Published: January 2014

Object

The objective of this study was to determine current practices regarding seizure prophylaxis in aneurysmal subarachnoid hemorrhage (aSAH).

Methods

An eight question survey was sent to 25 US centers with high volume aSAH cases (>100 annually). Respondents were asked about institutional practices regarding use, duration, and type of seizure prophylaxis.

Results

13 (52%) respondents endorsed the utility of seizure prophylaxis while 10 (40%) did not, and two (8%) were unsure. Among respondents using prophylaxis, levetiracetam was the firstline medication for the majority (94%) while phenytoin was used as a primary agent at one (4%) center and as a secondary agent at four (16%) centers. Duration of levetiracetam prophylaxis ranged from 1 day to 6 weeks following SAH (mean 13.2; median 11). Only a single center employed EEG routinely in all aSAH patients but most supported EEG use when the neurologic examination was unreliable or inexplicably declining. 24 (96%) respondents agreed that a trial randomizing patients to levetiracetam or no antiseizure medication is warranted at this time, and all 25 (100%) believed that such a trial would be appropriate or ethically sound.

Conclusions

The routine use of seizure prophylaxis following aSAH is controversial. Among a sampling of 25 major academic centers, most administer prophylaxis, while a significant proportion does not. The majority believes a trial randomizing patients to receive seizure prophylaxis is both timely and ethical.
Hepatoprotective effects of apple polyphenol extract on aluminum-induced liver oxidative stress in the rat
Authors: Cheng Dai , Zhu Chunqiu , Wang Cuntang , Xu Huiling , Cao Jiankang , Jiang Weibo
Published: January 2014

This study was undertaken to determine the effectiveness of apple (Ralls) polyphenol extract (APE) in modulating aluminum chloride (AlCl3) induced hepatotoxicity in rats. The rats were distributed among 4 groups and fed different diets with or without AlCl3(171.8 mg Al·kg−1·day−1) and APE (200 mg·kg−1·day−1) for 10 weeks. The activities of superoxide dismutase and catalase as well as the levels of glutathione and ATP synthesis were decreased by comparison with the control, while the activities of transaminases in serum, the levels of Al, and ATP hydrolysis were increased significantly in the liver of the Al-treated group. Furthermore, abnormal changes in the histological structure of the liver were observed in the Al-treated group. However, these toxic effects of Al were significantly reduced when the rats were fed diets supplemented with APE. This suggests that APE plays a role in the reduction of the toxic effects from Al in rats.
QUALITATIVE AND QUANTITATIVE STUDY OF TRACE ELEMENTS IN DRUGS (OPIUM, HASHISH, ECSTASY PILL) BY PIXE AND NAA
Authors: FAKHAR F. EBRAHIMI , MOALEMI S. , RACHTI M. LAMEHI , OLIAIY P. , ESMAEILI N. , SHOKOUHI F. , GHODS H. , TAHANI V.
Published: January 2014

In investigating drug addiction and its side effects from a social health point of view, the attention is usually focused on the drug itself. Yet trace amounts of other elements may have side effects no less harmful than addiction itself. The knowledge of these elements can be of help in the cure of drug addiction. The purpose of this study is to determine the trace elements in some drugs by methods of nuclear analysis. In this study, the Proton Induced X-ray Emission (PIXE) and Neutron Activation Analysis (NAA) techniques have been applied to measure the elemental composition and concentration of 55 opium, hashish and ecstasy pill samples. PIXE analysis shows the samples contain various elements including Mg, Al, Si, P, S, Cl, K, Ca, Ti, Fe, Cu, Zn, Rb and Sr .
DONAGI–MARKMAN CUBIC FOR THE GENERALIZED HITCHIN SYSTEM
Authors: BRUZZO UGO , DALAKOV PETER
Published: January 2014

Donagi and Markman (1993) have shown that the infinitesimal period map for an algebraic completely integrable Hamiltonian system (ACIHS) is encoded in a section of the third symmetric power of the cotangent bundle to the base of the system. For the ordinary Hitchin system the cubic is given by a formula of Balduzzi and Pantev. We show that the Balduzzi–Pantev formula holds on maximal rank symplectic leaves of the G-generalized Hitchin system.
Invariant trilinear forms on spherical principal series of real rank one semisimple Lie groups
Authors: Ben Said Salem , Koufany Khalid , Zhang Genkai
Published: January 2014

Let G be a connected semisimple real-rank one Lie group with finite center. We consider intertwining operators on tensor products of spherical principal series representations of G. This allows us to construct an invariant trilinear form [Formula: see text] indexed by a complex multiparameter [Formula: see text] and defined on the space of smooth functions on the product of three spheres in 𝔽n, where 𝔽 is either ℝ, ℂ, ℍ, or 𝕆 with n = 2. We then study the analytic continuation of the trilinear form with respect to (ν1, ν2, ν3), where we locate the hyperplanes containing the poles. Using a result due to Johnson and Wallach on the so-called "partial intertwining operator", we obtain an expression for the generalized Bernstein–Reznikov integral [Formula: see text] in terms of hypergeometric functions.
QUANTUM GROUP-TWISTED TENSOR PRODUCTS OF C*-ALGEBRAS
Authors: MEYER RALF , ROY SUTANU , WORONOWICZ STANISŁAW LECH
Published: January 2014

We put two C*-algebras together in a noncommutative tensor product using quantum group coactions on them and a bicharacter relating the two quantum groups that act. We describe this twisted tensor product in two equivalent ways, based on certain pairs of quantum group representations and based on covariant Hilbert space representations, respectively. We establish basic properties of the twisted tensor product and study some examples.
Lattice Boltzmann simulations of flapping wings: The flock effect and the lateral wind effect
Authors: De Rosis Alessandro
Published: January 2014

In this paper, numerical analysis aiming at simulating biological organisms immersed in a fluid are carried out. The fluid domain is modeled through the lattice Boltzmann (LB) method, while the immersed boundary method is used to account for the position of the organisms idealized as rigid bodies. The time discontinuous Galerkin method is employed to compute body motion. An explicit coupling strategy to combine the adopted numerical methods is proposed. The vertical take-off of a couple of butterflies is numerically simulated in different scenarios, showing the mutual interaction that a butterfly exerts on the other one. Moreover, the effect of lateral wind is investigated. A critical threshold value of the lateral wind is defined, thus corresponding to an increasing arduous take-off.
Seeing about soil — management lessons from a simple model for renewable resources
Authors: Lichtenegger Klaus , Schappacher Wilhelm
Published: January 2014

Employing an effective cellular automata model, we investigate and analyze the build-up and erosion of soil. Depending on the strategy employed for handling agricultural production, in many cases we find a critical dependence on the prescribed production target, with a sharp transition between stable production and complete breakdown of the system.

Strategies which are particularly well-suited for mimicking real-world management approaches can produce almost cyclic behavior, which can also either lead to sustainable production or to breakdown.

While designed to describe the dynamics of soil evolution, this model is quite general and may also be useful as a model for other renewable resources and may even be employed in other disciplines like psychology.
A variational model of interaction between continuum and discrete systems
Authors: Alicandro Roberto , Ansini Nadia
Published: January 2014

We consider a variational model which describes a complex system composed, in its reference configuration, of a periodic distribution of "small" interacting particles immersed in a continuous medium. We describe its macroscopic limit via Gamma-convergence, highlighting different regimes. In particular, we show how the interplay between the particles and the continuum leads, for a critical size of the particles, to a capacitary term. Eventually, we discuss how the presence of a continuum affects the properties of the ground states of the system of particles in terms of the validity or not of the so-called "Cauchy–Born" rule.
hp-Version discontinuous Galerkin methods on polygonal and polyhedral meshes
Authors: Cangiani Andrea , Georgoulis Emmanuil H. , Houston Paul
Published: January 2014

An hp-version interior penalty discontinuous Galerkin method (DGFEM) for the numerical solution of second-order elliptic partial differential equations on general computational meshes consisting of polygonal/polyhedral elements is presented and analyzed. Utilizing a bounding box concept, the method employs elemental polynomial bases of total degree p (𝒫p-basis) defined on the physical space, without the need to map from a given reference or canonical frame. This, together with a new specific choice of the interior penalty parameter which allows for face-degeneration, ensures that optimal a priori bounds may be established, for general meshes including polygonal elements with degenerating edges in two dimensions and polyhedral elements with degenerating faces and/or edges in three dimensions. Numerical experiments highlighting the performance of the proposed method are presented. Moreover, the competitiveness of the p-version DGFEM employing a 𝒫p-basis in comparison to the conforming p-version finite element method on tensor-product elements is studied numerically for a simple test problem.
Quasistatic evolution models for thin plates arising as low energy Γ-limits of finite plasticity
Authors: Davoli Elisa
Published: January 2014

In this paper we deduce by Γ-convergence some partially and fully linearized quasistatic evolution models for thin plates, in the framework of finite plasticity. Denoting by ε the thickness of the plate, we study the case where the scaling factor of the elasto-plastic energy is of order ε2α-2, with α ≥ 3. These scalings of the energy lead, in the absence of plastic dissipation, to the Von Kármán and linearized Von Kármán functionals for thin plates. We show that solutions to the three-dimensional quasistatic evolution problems converge, as the thickness of the plate tends to zero, to a quasistatic evolution associated to a suitable reduced model depending on α.
The geometric origin of Lie point symmetries of the Schrödinger and the Klein–Gordon equations
Authors: Paliathanasis Andronikos , Tsamparlis Michael
Published: January 2014

We determine the Lie point symmetries of the Schrödinger and the Klein–Gordon equations in a general Riemannian space. It is shown that these symmetries are related with the homothetic and the conformal algebra of the metric of the space, respectively. We consider the kinematic metric defined by the classical Lagrangian and show how the Lie point symmetries of the Schrödinger equation and the Klein–Gordon equation are related with the Noether point symmetries of this Lagrangian. The general results are applied to two practical problems: (a) The classification of all two- and three-dimensional potentials in a Euclidean space for which the Schrödinger equation and the Klein–Gordon equation admit Lie point symmetries; and (b) The application of Lie point symmetries of the Klein–Gordon equation in the exterior Schwarzschild spacetime and the determination of the metric by means of conformally related Lagrangians.
Optical, electrochemical, third-order nonlinear optical, and excited state dynamics studies of thio-zinc phthalocyanine
Authors: Swain Debasis , Singh Varun K. , Krishna Narra V. , Giribabu L. , Rao S. Venugopal
Published: January 2014

Zinc phthalocyanine with S-aryl groups at α-positions have been synthesized and its optical, emission, electrochemical and third-order nonlinear optical properties were investigated. Both the Soret and Q-bands were red-shifted and obeyed Beer–Lambert's law. Electrochemical properties indicated that both oxidation and reduction processes were ring centered. Emission spectra were recorded in different solvents and the fluorescence yields obtained were in the range of 0.02 while time-resolved fluorescence data revealed lifetimes of typically few ns. Excited state dynamics in this novel thio-zinc phthalocyanine molecule has been investigated using femtosecond (fs) degenerate pump-probe spectroscopy. Nonlinear optical properties of this molecule have been examined using the Z-scan technique with picosecond (ps) and fs pulses. Both open and closed aperture Z-scan curves were recorded with ~2 ps/~150 fs laser pulses at a wavelength of 800 nm and nonlinear optical coefficients were extracted from both the studies. Degenerate pump-probe data performed at 600 nm suggested a single long lifetime of ~300 ps, possibly originating from the non-radiative decay of S1 state.
Early-Starting Conduct Problems: Intersection of Conduct Problems and Poverty
Authors: Shaw Daniel S. , Shelleby Elizabeth C.
Published: January 2014

The current article reviews extant literature on the intersection between poverty and the development of conduct problems (CP) in early childhood. Associations between exposure to poverty and disruptive behavior are reviewed through the framework of models emphasizing how the stressors associated with poverty indirectly influence child CP by compromising parent psychological resources, investments in children's welfare, and/or caregiving quality. We expand on the best-studied model, the family stress model, by emphasizing the mediating contribution of parent psychological resources on children's risk for early CP, in addition to the mediating effects of parenting. Specifically, we focus on the contribution of maternal depression, in terms of both compromising parenting quality and exposing children to higher levels of stressful events and contexts. Implications of the adapted family stress model are then discussed in terms of its implications for the prevention and treatment of young children's emerging CP.
Overnutrition induces β-cell differentiation through prolonged activation of β-cells in zebrafish larvae
Authors: Li Mingyu , Maddison Lisette A. , Page-McCaw Patrick , Chen Wenbiao
Published: January 2014

Insulin from islet β-cells maintains glucose homeostasis by stimulating peripheral tissues to remove glucose from circulation. Persistent elevation of insulin demand increases β-cell number through self-replication or differentiation (neogenesis) as part of a compensatory response. However, it is not well understood how a persistent increase in insulin demand is detected. We have previously demonstrated that a persistent increase in insulin demand by overnutrition induces compensatory β-cell differentiation in zebrafish. Here, we use a series of pharmacological and genetic analyses to show that prolonged stimulation of existing β-cells is necessary and sufficient for this compensatory response. In the absence of feeding, tonic, but not intermittent, pharmacological activation of β-cell secretion was sufficient to induce β-cell differentiation. Conversely, drugs that block β-cell secretion, including an ATP-sensitive potassium (KATP) channel agonist and an L-type Ca2+ channel blocker, suppressed overnutrition-induced β-cell differentiation. Genetic experiments specifically targeting β-cells confirm existing β-cells as the overnutrition sensor. First, inducible expression of a constitutively active KATP channel in β-cells suppressed the overnutrition effect. Second, inducible expression of a dominant-negative KATP mutant induced β-cell differentiation independent of nutrients. Third, sensitizing β-cell metabolism by transgenic expression of a hyperactive glucokinase potentiated differentiation. Finally, ablation of the existing β-cells abolished the differentiation response. Taken together, these data establish that overnutrition induces β-cell differentiation in larval zebrafish through prolonged activation of β-cells. These findings demonstrate an essential role for existing β-cells in sensing overnutrition and compensating for their own insufficiency by recruiting additional β-cells.
An Improved Topology-Potential-Based Community Detection Algorithm for Complex Network
Authors: Wang Zhixiao , Zhao Ya , Chen Zhaotong , Niu Qiang
Published: January 2014

Topology potential theory is a new community detection theory on complex network, which divides a network into communities by spreading outward from each local maximum potential node. At present, almost all topology-potential-based community detection methods ignore node difference and assume that all nodes have the same mass. This hypothesis leads to inaccuracy of topology potential calculation and then decreases the precision of community detection. Inspired by the idea of PageRank algorithm, this paper puts forward a novel mass calculation method for complex network nodes. A node’s mass obtained by our method can effectively reflect its importance and influence in complex network. The more important the node is, the bigger its mass is. Simulation experiment results showed that, after taking node mass into consideration, the topology potential of node is more accurate, the distribution of topology potential is more reasonable, and the results of community detection are more precise.
Modyfication of the Rigid Polyurethane-Polyisocyanurate Foams
Authors: Czupryński Bogusław , Liszkowska Joanna , Paciorek-Sadowska Joanna
Published: January 2014

The effect of polyethylene glycol 1500 on physicomechanical properties of rigid polyurethane-polyisocyanurate (PUR-PIR) foams has been studied. It was found that application of polyethylene glycol 1500 for synthesis of foams in amount from 0% to 20%w/whad an effect on reduction of brittleness and softening point, while the greater the increase in compressive strength the higher its content in foam composition was. Wastes from production of these foams were ground and subjected to glycolysis in diethylene glycol with the addition of ethanolamine and zinc stearate. Liquid brown products were obtained. Properties of the resulting products were defined in order to determine their suitability for synthesis of new foams. It was found that glycolysate 6 was the most suitable for reuse and its application in different amounts allowed us to prepare 4 new foams (nos. 25, 26, 27, and 28). Properties of foams prepared in this manner were determined and, on their basis, the suitability of glycolysates for production of rigid PUR-PIR foams was evaluated.