bluuebunny/crossref_metadata_2025 huggingface dataset:
Preliminary Fluid Dynamic Analysis of Turbulent Flat and Ribbed Square Duct via CFD Approach
Authors: Mereu Riccardo , Lampitella Paolo , Inzoli Fabio
Published: December 2014

A preliminary numerical study of the fluid dynamic behavior of flat and ribbed square duct is presented. Fluid dynamics of two configurations is analyzed via Reynolds Averaged Navier Stokes (RANS) modeling in order to underline the main characteristics of each configuration and to give some information at global and local level. This kind of modeling is used as base for setting up a more detailed analysis such as Direct Numerical Simulation (DNS).

Flat and ribbed square duct with a Reynolds number based on bulk velocity and hydraulic diameter of 10320 (Reτ=600 for the flat configuration) are analyzed and the results of the flat configuration are compared with available results obtained via DNS approach.

The ribbed square duct is characterized by a two-pass configuration (aligned ribs in the top and bottom walls), with the duct height about six times the height of the obstacles for a blockage ratio of about 30%. Finally a pitch ratio (rib spacing to rib height) of 10 is used in order to obtain a k-type roughness permitting the flow to reattach before the next obstacle.

Advanced U-RANS and RANS models such as Reynolds Stress Models (RSM), Explicit Algebraic Stress Models (EASM), v2f, and two-equation low Reynolds models have been used and compared.

In this direction the validated results obtained for the smooth square duct are used to select the most appropriate RANS models and to evaluate their performance for a ribbed square duct at the same Reynolds number.

A periodic configuration including one rib and considering the flow fully developed is used to reduce computational costs. The results of the ribbed square duct are hence analyzed in order to evaluate characteristics such as domain and mesh size.
Comprehensive Soft Impact Damage Methodology for Advanced High Bypass Ratio Turbofan Engines
Authors: Song Yangkun , Bayandor Javid
Published: December 2014

Foreign object strikes are one of the major aviation incidents that cause tremendous risk to both the aircraft and passengers, the adverse implications of which can ripple through the aviation industry. The demand for air transportation has been on the rise, leading to foreign object ingestion into the engines becoming one of the most threatening scenarios. In January 2009, Flight 1549 took off from LaGuardia Airport in New York City and struck a flock of Canadian Geese during takeoff. Both engines ingested birds, resulting in mid-air catastrophic engine failure. Fortunately, none of the damaged engine components penetrated into the cabin and the aircraft successfully completed an emergency landing on the Hudson River without incurring any casualties.

In this work, explicit finite element strategies have been adopted to model the Fluid-Solid Interactions (FSI) present in a bird ingestion scenario. Taking into account the fluidic composition of bird bodies, a proper methodology to model the Fluid-Solid Interaction was implemented. The investigations were aimed to understand the significance of impact force histograms in an accurately represented model, analyze shockwave propagations and reflections during the impact window, and perform parametric studies to highlight a superior representation for the Fluid-Solid Interaction (FSI). The paper presents a modern explicit finite element methodology adopted to accurately model bird ingestion into a complex turbomachinery forward section and analyze subsequent failure sequencing of the relevant structural components within the system.
Numerical Solution of Wavy-Stratified Fluid-Fluid Flow With the One-Dimensional Two-Fluid Model: Stability, Boundedness, Convergence and Chaos
Authors: Fullmer William D. , Clausse Alejandro , Vaidheeswaran Avinash , Lopez de Bertodano Martin A.
Published: December 2014

In this paper the one-dimensional two-fluid model is used to dynamically simulate slightly inclined fluid-fluid flow in a rectangular channel. By that, it is specifically meant that the solutions exhibit a wavy pattern arising from the inherent instability of the model. The conditions and experimental data of Thorpe (1969) are used for comparison. The linear instability of the model is regularized, i.e., made well-posed, with surface tension and axial turbulent stress with a simple turbulent viscosity model. Nonlinear analysis in an infinite domain demonstrates for the first time one-dimensional two-fluid model chaotic behavior in addition to limit cycle behavior and asymptotic stability. The chaotic behavior is a consequence of the linear instability (the long wavelength energy source) the nonlinearity (the energy transfer mechanism) and the viscous dissipation (the short wavelength energy sink). Since the model is chaotic, solutions exhibit sensitive dependence on initial conditions which results in non-convergence of particular solutions with grid refinement. However, even chaotic problems have invariants and the ensemble averaged water void fraction amplitude spectrum is used to demonstrate convergence and make comparisons to the experimental data.
Behavior of Janus Particles at Liquid Interfaces
Authors: Rezvantalab Hossein , Shojaei-Zadeh Shahab
Published: December 2014

We study the capillary-induced interactions and configuration of spherical and non-spherical Janus particles adsorbed at flat liquid-fluid interfaces. For Janus spheres, the equilibrium orientation results in each hemisphere being exposed to its more favored fluid. However, experimental observations suggest that some of these particles may take a tilted orientation at the interface, giving rise to a deformed interface. On the other hand, Janus ellipsoids with a large aspect ratio or a small difference in the wettability of the two regions tend to tilt even at equilibrium. The overlap of deformed menisci results in energetic interactions between neighboring particles. We numerically calculate the interface shape around the particles by minimizing the total surface energy of the system comprising of the interface and particle-fluid regions. We quantify these interactions through evaluation of capillary energy variation as a function of the orientation and separation distance between the particles. We find that Janus spheres with similar orientations undergo a relative realignment in the interface plane in order to minimize the capillary energy. In case of ellipsoidal particles, the particles assemble in a preferred side-by-side configuration. We evaluate the role of anisotropy and degree of amphiphilicity on the inter-particle force and the capillary torque. The results can be used to predict the migration and oriented assembly of Janus particles with various geometrical and surface properties at liquid-fluid interfaces.
Investigation of the Heat Transfer Process in a PCM During Melting Phase
Authors: Bashar Mohammad , Siddiqui Kamran
Published: December 2014

Thermal energy storage systems are gaining significance due to their potential use to store renewable energy and waste heat. Phase change materials (PCMs) are considered to be an efficient way to store thermal energy. However, the heat transfer process during the phase change is not well understood. We report on an experimental study conducted to investigate the heat transfer process in a PCM during melting phase. A PCM storage system subjected to bottom heating from a horizontal heated cylinder was considered using wax as the PCM. An imaging technique was used to capture the movement of the solid-liquid interface. Temperature was measured at multiple locations to quantify the heat transfer process. The interface was found to move with a relatively uniform velocity throughout the melting process however, the heat transfer rate was significantly enhanced in the melted (liquid) phase. The local heat transfer coefficient was found to decrease with an increase in the liquid fraction.
The Effects of a Passively Actuated Trailing Edge on the Aerodynamics of an Oscillating Wing
Authors: Rushen Jesse , Siala Firas , Totpal Alexander D. , Planck Cameron J. , Liburdy James A.
Published: December 2014

This study examines the use of a passively actuated trailing edge of a thin wing during oscillation motion. The integration of a flexible trailing edge with an oscillating wing has the ability to alter the transient lift and drag characteristics, as well as the time averaged values. The results are obtained for a chord-length based Reynolds number of 0 and 40,000, and at oscillation frequencies of 0.5 and 1 Hz. The non-dimensional heaving amplitude is fixed at 0.25 and the pitching is 20°. The flexibility of the trailing edge is controlled by a torsion rod between the main wing and the trailing edge. Three conditions are evaluated: a very stiff rod (essentially non-flexible trailing edge), a moderately flexible rod and a very flexible rod. Results obtained indicate that lift and drag have a shift in the time averaged values, where the drag and lift both decrease as the trailing edge flexibility increases. These findings have application to both enhanced propulsion and energy harvesting.
Steady-State and Unsteady Simulations of a High Velocity Jet Into a Venturi Shaped Pipe
Authors: Semlitsch Bernhard , Laurendeau Estelle , Mihăescu Mihai
Published: December 2014

A jet pump consists mainly of a convergent-divergent Venturi shaped duct where a primary stream is applied with the role of entraining a secondary jet. Due to their simple and reliable concept, jet pumps are used in miscellaneous applications. Performance optimization of a jet pump has to be performed for various operation conditions. Thus, numerically robust and cheap models, able to predict accurately the performance parameters of such devices are necessary. Reynolds Averaged Navier-Stokes based formulations are computationally efficient to predict the performance of a jet pump. However, these simulations rely on turbulence closure coefficients, which need to be validated with experimental observations. Large Eddy Simulation solves the most energetic structures in the flow field and it can be used to capture the flow dynamics. On the experimental side, confined geometries challenge the investigation capabilities to capture the flow field accurately and in all the details.

The flow field in the jet pump is investigated using Large Eddy Simulation approach and a steady state Reynolds Averaged Navier-Stokes formulation. The flow field solutions obtained with the two numerical tools are compared. A reasonable agreement for the velocity and pressure contours could be achieved. However, the turbulence kinetic energy distribution and the entrained mass flow rate are predicted to be distinct. The difference in entrained mass flow rate leads to differences in jet pump efficiency estimation.
Three Dimensional Simulation of Blood Flow in the Small Arteries of a Truncated Vascular System With Three Levels of Bifurcation
Authors: Kahveci Kamil , Becker Bryan R.
Published: December 2014

Three dimensional blood flow in a truncated vascular system is investigated numerically using a commercially available finite element analysis and simulation software. The vascular system considered in this study has three levels of symmetric bifurcation. Geometric parameters for daughter vessels, such as their diameters and their angles of bifurcation, are specified according to Murray’s law based on the principle of minimum work. The ratio of blood vessel length to diameter is based upon experimental data found in the literature. An experimentally obtained velocity profile, available in the literature, is used as the inlet boundary condition. An outflow boundary model, consisting of a contraction tube to represent the pressure drop of the small arteries, arterioles, and capillaries that would follow the truncated vascular system, is used to specify the boundary condition at the eight outlets. The results show that although the blood flow velocity experiences a sudden decrease after the bifurcation points due to the higher total cross-sectional area of the daughter vessels as compared to the parent vessel, this decrease in velocity is partially recovered due to the tapering of the blood vessels as they approach the next bifurcation point. The results also show that the secondary flow which is typical after the bifurcation of large arteries does not develop after the bifurcation of small arteries due to the presence of laminar blood flow with very low Reynolds number in the small arteries. The numerical model yields pressure distributions and pressure drops along the vascular system that agree quite well with the physiological data found in the literature. Finally, the results show that, immediately following a bifurcation, the blood flow velocity profile is not symmetrical about the longitudinal axes of blood vessel. However, symmetry is recovered as the blood flow proceeds down the vessel.
Design and Experimental Study on the Surge Performance Improvement by the Effects of Bleed Slot Casing of a Centrifugal Compressor
Authors: Kim Hong Won , Chung Jae Hoon , Lee Hyo Seong , Choi Min Ouk
Published: December 2014

The primary design goal of a compressor is focused on improving efficiency. Secondary objective is to widen the compressor’s operating range. This paper presents a numerical and experimental investigation of the influence of the bleed slot to enlarge operating range for the 1.2MW class centrifugal compressor installed in a turbocharger. The main design parameters of the bleed slot casing are upstream slot position, inlet pipe slope, downstream slot position and width. The DOE (design of experiment) method was carried out to optimize the casing design. Numerical analyses were done by the commercial code ANSYS-CFX based on the three dimensional Reynolds-averaged Navier-Stokes equations. From the analysis, as the downstream slot position and width are smaller and upstream position is located away from impeller inlet, efficiency and pressure ratio are increased.

Experimental works were done with and without the bleed slot casing. The simulation results were in good agreement with the test data. In case without the bleed slot casing, the surge margin value came out to be only 11.8% but with the optimized bleed slot design, the surge margin reached 23%. Therefore, the surge margin increase of 11.2% was achieved.
Numerical Simulation and Modelling of the Forces Acting on Single and Multiple Non-Spherical Particles
Authors: Ouchene Rafik , Chadil Amine , Fede Pascal , Khalij Mohammed , Tanière Anne , Vincent Stéphane , Estivalezès Jean-Luc , Arcen Boris
Published: December 2014

The paper deals with gas-solid turbulent flows carrying non-spherical particles. The main objective of the present paper is to compute the hydrodynamics forces on non-spherical particles as a function of the particle orientation, for different particle shapes and a large range of particle Reynolds number. Two Direct Numerical Simulations at the scale of the particle are used, i.e. a body-fitted approach and a viscous penalty approach, in the case of a uniform flow with a single ellipsoidal particle. Results are compared with several correlations from the literature and a new proposal for the drag coefficient is given. The study is then extended to the case of a lattice of non-spherical particles to measure the pressure drop and to connect it with the drag coefficient.
Modeling Wave Attenuation With Rigid Vegetation Plants
Authors: Liu Don , Zheng Yonglai
Published: December 2014

Virtual Cylinder Model (VCM) was used to simulate flows over vegetation plants (cylinders) in coastal wetlands. VCM is capable of characterizing the flow field with a few plants as well as numerous plants with high efficiency and accuracy. Numerical results of flow over cylinders at a regular pattern are compared with Direct Numerical Simulations and at irregular patterns are presented with varied resolutions. VCM provides decent accuracy and efficiency without high resolution in tiny mesh. Results demonstrate that it is suitable for large-scale simulation of vegetation resilience to protect coastal wetlands from waves.
Viscoelasticity of vibrated granular suspensions
Authors: Hanotin C. , Kiesgen de Richter S. , Michot L. J. , Marchal Ph.
Published: December 2014

We propose, in this paper, a model for predicting the rheological response of both vibrated and sheared 3D granular suspensions in stationary and nonstationary conditions. The major assumption of this model is the inherent bimodal behavior of chain forces in granular packings. The model is set up from a kinetic equation describing the dynamic exchange between a population of strongly correlated caged particles and a population of slightly correlated free particles. To compare the predictions of the model to experimental results, the kinetic equation is transformed into a differential constitutive equation, relating stress to strain, by including the effect of the interstitial fluid on the suspension. With only four adjustable parameters intrinsic to the system (i.e., independent of the type of rheological test used), the model is in very close agreement with experiments. Despite the fact that our approach remains at a mean-field level, it is able to predict and describe several rheological behaviors, in stationary, nonstationary conditions, linear and nonlinear regimes, including Newtonian and frictional Coulombian regimes, as well as elastic Hookean and viscoelastic Maxwellian behaviors. It then appears that this two-state approach allows capturing both the viscoelastic behavior of dry granular materials and granular suspensions. Vibrated dense suspensions and granular media are thus unified under a common framework.
Use of Inertial Measurement Units to Assess Age-related Changes in Gait Kinematics in an Active Population
Authors: Monda M. , Goldberg A. , Smitham P. , Thornton M. , McCarthy I.
Published: December 2014

To study mobility in older populations it can be advantageous to use portable gait analysis systems, such as inertial measurement units (IMUs), which can be used in the community. To define a normal range, 136 active subjects were recruited with an age range of 18 to 97. Four IMUs were attached to the subjects, one on each thigh and shank. Subjects were asked to walk 10 m at their own self-selected speed. The ranges of motion of thigh, shank, and knee in both swing and stance phase were calculated, in addition to stride duration. Thigh, shank, and knee range of movement in swing and stance were significantly different only in the > 80 age group. Regressions of angle against age showed a cubic relationship. Stride duration showed a weak linear relationship with age, increasing by approximately 0.1% per year.
Competitive Bodybuilding: Positive Deviance, Body Image Pathology, or Modern Day Competitive Sport?
Authors: Suffolk Mark T.
Published: December 2014

The sport of competitive bodybuilding is strongly associated with muscle dysmorphia, a body-image-related psychological disorder. This theoretical article draws on existing concepts, namely stereotyping, prejudice, and positive deviance in sport, to explicate the notion that competitive bodybuilding and body-image disturbance may be mistakenly conflated. The perspective offered here goes beyond the countercultural physique to argue that a negative social perception of competitive bodybuilders obscures the pragmatic necessity to develop a hypermesomorphic physique. Competitive bodybuilders (CBs) and athletes in mainstream competitive sport exhibit congruent psychobehavioral tendencies. In a competitive-sport context, behavior among CBs perceived as pathological may primarily represent a response to the ideological sporting ethic of “win at all costs,” not extreme body-image disturbance. Analyzing the psychobehavioral characteristics of CBs within a sporting rather than a pathological framework, allows for a contextual assessment of behaviors to then determine the clinical significance relative to the research population under investigation.
Best Practices for the Use of Inventories in Sport Psychology Consulting
Authors: Anshel Mark H. , Brinthaupt Thomas M.
Published: December 2014

Psychological inventories are ubiquitous and necessary in sport psychology for gathering data to address selected research questions, making clinical diagnoses, and as guidelines for providing effective interventions. However, the improper use of inventories can result in inaccurate or incomplete interpretations of data or diagnoses, thereby compromising the effectiveness of intervention efforts and limiting the contributions of sport psychology consulting. The purposes of this article are to (a) summarize the major terminology associated with the use of psychological inventories, (b) provide an overview of reliability and validity issues relevant to establishing psychometric evidence for psychological inventories, (c) review the most common errors associated with using sport psychology inventories, and (d) provide best practice guidelines for the proper use of psychological inventories in sport psychology. If researchers and practitioners follow these guidelines, they can be more confident in the results and proper use of their interventions and consultations.
Colonization in the Photic Zone and Subsequent Changes during Sinking Determine Bacterial Community Composition in Marine Snow
Authors: Thiele Stefan , Fuchs Bernhard M. , Amann Rudolf , Iversen Morten H.
Published: December 2014

Due to sampling difficulties, little is known about microbial communities associated with sinking marine snow in the twilight zone. A drifting sediment trap was equipped with a viscous cryogel and deployed to collect intact marine snow from depths of 100 and 400 m off Cape Blanc (Mauritania). Marine snow aggregates were fixed and washed
in situ
to prevent changes in microbial community composition and to enable subsequent analysis using catalyzed reporter deposition fluorescence
in situ
hybridization (CARD-FISH). The attached microbial communities collected at 100 m were similar to the free-living community at the depth of the fluorescence maximum (20 m) but different from those at other depths (150, 400, 550, and 700 m). Therefore, the attached microbial community seemed to be “inherited” from that at the fluorescence maximum. The attached microbial community structure at 400 m differed from that of the attached community at 100 m and from that of any free-living community at the tested depths, except that collected near the sediment at 700 m. The differences between the particle-associated communities at 400 m and 100 m appeared to be due to internal changes in the attached microbial community rather than
de novo
colonization, detachment, or grazing during the sinking of marine snow. The new sampling method presented here will facilitate future investigations into the mechanisms that shape the bacterial community within sinking marine snow, leading to better understanding of the mechanisms which regulate biogeochemical cycling of settling organic matter.
Engineering of Glarea lozoyensis for Exclusive Production of the Pneumocandin B
0
Precursor of the Antifungal Drug Caspofungin Acetate
Authors: Chen Li , Yue Qun , Li Yan , Niu Xuemei , Xiang Meichun , Wang Wenzhao , Bills Gerald F. , Liu Xingzhong , An Zhiqiang
Published: December 2014

Pneumocandins produced by the fungus
Glarea lozoyensis
are acylated cyclic hexapeptides of the echinocandin family. Pneumocandin B
0
is the starting molecule for the first semisynthetic echinocandin antifungal drug, caspofungin acetate. In the wild-type strain, pneumocandin B
0
is a minor fermentation product, and its industrial production was achieved by a combination of extensive mutation and medium optimization. The pneumocandin biosynthetic gene cluster was previously elucidated by a whole-genome sequencing approach. Knowledge of the biosynthetic cluster suggested an alternative way to produce exclusively pneumocandin B
0
. Disruption of
GLOXY4
, encoding a nonheme, α-ketoglutarate-dependent oxygenase, confirmed its involvement in
l
-leucine cyclization to form 4
S
-methyl-
l
-proline. The absence of 4
S
-methyl-
l
-proline abolishes pneumocandin A
0
production, and 3
S
-hydroxyl-
l
-proline occupies the hexapeptide core's position 6, resulting in exclusive production of pneumocandin B
0
. Retrospective analysis of the
GLOXY4
gene in a previously isolated pneumocandin B
0
-exclusive mutant (ATCC 74030) indicated that chemical mutagenesis disrupted the
GLOXY4
gene function by introducing two amino acid mutations in GLOXY4. This one-step genetic manipulation can rationally engineer a high-yield production strain.
Improved Antimicrobial Activities of Synthetic-Hybrid Bacteriocins Designed from Enterocin E50-52 and Pediocin PA-1
Authors: Tiwari Santosh Kumar , Sutyak Noll Katia , Cavera Veronica L. , Chikindas Michael L.
Published: December 2014

Two hybrid bacteriocins, enterocin E50-52/pediocin PA-1 (EP) and pediocin PA-1/enterocin E50-52 (PE), were designed by combining the N terminus of enterocin E50-52 and the C terminus of pediocin PA-1 and by combining the C terminus of pediocin PA-1 and the N terminus of enterocin E50-52, respectively. Both hybrid bacteriocins showed reduced MICs compared to those of their natural counterparts. The MICs of hybrid PE and EP were 64- and 32-fold lower, respectively, than the MIC of pediocin PA-1 and 8- and 4-fold lower, respectively, than the MIC of enterocin E50-52. In this study, the effect of hybrid as well as wild-type (WT) bacteriocins on the transmembrane electrical potential (ΔΨ) and their ability to induce the efflux of intracellular ATP were investigated. Enterocin E50-52, pediocin PA-1, and hybrid bacteriocin PE were able to dissipate ΔΨ, but EP was unable to deplete this component. Both hybrid bacteriocins caused a loss of the intracellular concentration of ATP. EP, however, caused a faster efflux than PE and enterocin E50-52. Enterocin E50-52 and hybrids PE and EP were active against the Gram-positive and Gram-negative bacteria tested, such as
Micrococcus luteus
,
Salmonella enterica
serovar Enteritidis 20E1090, and
Escherichia coli
O157:H7. The hybrid bacteriocins designed and described herein are antimicrobial peptides with MICs lower those of their natural counterparts. Both hybrid peptides induce the loss of intracellular ATP and are capable of inhibiting Gram-negative bacteria, and PE dissipates the electrical potential. In this study, the MIC of hybrid bacteriocin PE decreased 64-fold compared to the MIC of its natural peptide counterpart, pediocin PA-1. Inhibition of Gram-negative pathogens confers an additional advantage for the application of these peptides in therapeutics.
Clearance of Escherichia coli O157:H7 Infection in Calves by Rectal Administration of Bovine Lactoferrin
Authors: Kieckens E. , Rybarczyk J. , De Zutter L. , Duchateau L. , Vanrompay D. , Cox E.
Published: December 2014

Enterohemorrhagic
Escherichia coli
(EHEC) strains, of which
E. coli
O157:H7 is the best-studied serotype, are an important group of foodborne pathogens causing severe illness in humans worldwide. The main reservoirs for EHEC are ruminants, mostly cattle, which harbor the bacteria in their intestinal tracts without showing clinical symptoms. In this study, we used bovine lactoferrin, a natural occurring bactericidal and immunomodulating protein, as an antibacterial agent against EHEC infection in cattle. Nine 3-month-old Holstein-Friesian calves were experimentally infected with EHEC (strain NCTC12900). Three animals received a daily rectal spray treatment with bovine lactoferrin, three animals received an oral treatment, and three animals served as a control group. Blood samples were collected weekly and fecal samples twice weekly to monitor antibody responses and fecal excretion, respectively. Animals in the rectal group ceased shedding within 26 days of the experimental treatment and remained negative. This beneficial effect of bovine lactoferrin was not observed in the oral group, where animals were still shedding at the time of euthanasia (day 61). All groups developed serum responses, but no clear differences could be observed between the groups. However, the results indicate that the use of bovine lactoferrin as a rectal treatment can be a useful strategy to preclude further transmission of EHEC infections from cattle to humans.
Life-saving implantable cardioverter defibrillator therapy in cardiac AL amyloidosis
Authors: Patel Ketna S , Hawkins Philip N , Whelan Carol J , Gillmore Julian D
Published: December 2014

Cardiac involvement is the main determinant of prognosis in systemic monoclonal immunoglobulin light chain (AL) amyloidosis. Ventricular arrhythmias and sudden cardiac death are not uncommon. The electrical events that precede sudden death, and their potential to be treated effectively, remain undefined. There are no European guidelines for the use of implantable cardioverter defibrillator (ICD) in amyloidosis. ICDs in general are not usually offered to patients with a life expectancy of less than 1 year. We describe a patient who presented with cardiac AL amyloidosis who underwent prophylactic ICD implantation for the prevention of sudden cardiac death during treatment with chemotherapy, in whom life-threatening ventricular arrhythmia was successfully terminated over a 3-year period.
Fatal lymphomatoid granulomatosis with primary CNS-involvement in an immunocompetent 80-year-old woman
Authors: Olmes David G , Agaimy Abbas , Kloska Stephan , Linker Ralf A
Published: December 2014

An 80-year-old woman presented with weight loss, fatigue, dizziness and a brain stem lesion. Extensive work-up revealed lymphomatoid granulomatosis (LYG) with primary clinical manifestation in the central nervous system (CNS), a rare Epstein-Barr virus-driven multisystem lymphoproliferative disorder, to be causative for the symptoms. Immunochemotherapy consisting of rituximab and temozolomide was started, but the disease progressed and the patient subsequently died. Histology, diagnostic criteria, differential diagnosis and treatment options for LYG with CNS involvement are discussed. This case demonstrates that LYG with CNS involvement may necessitate more aggressive treatment approaches than combination therapy with rituximab and temozolomide.
Cardiac tamponade in a neonate: a dreadful condition—need for functional echo
Authors: Iyer Venkatesh Harohalli Aswathanarayana , Sharma Deepa Mohan , Charki Siddhu , Mohanty Pankaj Kumar
Published: December 2014

Cardiac tamponade is a clinical emergency. Detection of a swinging heart rate is one of the earliest markers of large pericardial effusion, in which the four cardiac chambers are free to float in a phasic manner. We present a case of a preterm baby, one of the twins, who developed sudden onset of deterioration in the form of swinging heart rate, fluctuation in blood pressure and desaturation, requiring emergency intubation and inotropic support. Bedside functional echo was performed, which demonstrated cardiac tamponade; an immediate echocardiography-guided tap was initiated and fluid was aspirated from the pericardial space.
Metastatic breast cancer presenting as detrusor overactivity
Authors: Balachandran Aswini Aparna , Duckett Jonathan
Published: December 2014

Breast carcinoma metastatic to the bladder is rare and accounts for approximately 3% of all secondary bladder neoplasms. We examine a case of breast cancer metastatic to the bladder with normal findings at cystoscopy. A 53-year-old woman with a history of breast carcinoma presented with a 6-month history of severe urgency and urgency incontinence. Treatment with multiple antimuscarinic therapies was unsuccessful. Vaginal examination demonstrated a non-mobile uterus with a suggestion of parametrial thickening. Urodynamic studies confirmed detrusor overactivity. CT showed a thickened bladder wall and cystoscopy revealed normal bladder mucosa with reduced bladder capacity. Bladder biopsies identified a poorly differentiated adenocarcinoma with strong oestrogen receptor staining. This was reported as a secondary deposit from a primary breast malignancy. The patient is currently under the care of the breast team and undergoing palliative chemotherapy.
Interventions targeting the elderly population to reduce emergency department utilisation: a literature review
Authors: Fan Lijun , Lukin William , Zhao Jingzhou , Sun Jiandong , Hou Xiang-Yu
Published: December 2014

Objective

High utilisation of emergency department (ED) among the elderly is of worldwide concern. This study aims to review the effectiveness of interventions targeting the elderly population in reducing ED utilisation.

Methods

Major biomedical databases were searched for relevant studies. Qualitative approach was applied to derive common themes in the myriad interventions and to critically assess the variations influencing interventions’ effectiveness. Quality of studies was appraised using the Effective Public Health Practice Project (EPPHP) tool.

Results

36 studies were included. Nine of 16 community-based interventions reported significant reductions in ED utilisation. Five of 20 hospital-based interventions proved effective while another four demonstrated failure. Seven key elements were identified. Ten of 14 interventions associated with significant reduction on ED use integrated at least three of the seven elements. All four interventions with significant negative results lacked five or more of the seven elements. Some key elements including multidisciplinary team, integrated primary care and social care often existed in effective interventions, while were absent in all significantly ineffective ones.

Conclusions

The investigated interventions have mixed effectiveness. Our findings suggest the hospital-based interventions have relatively poorer effects, and should be better connected to the community-based strategies. Interventions seem to achieve the most success with integration of multi-layered elements, especially when incorporating key elements such as a nurse-led multidisciplinary team, integrated social care, and strong linkages to the longer-term primary and community care. Notwithstanding limitations in generalising the findings, this review builds on the growing body of evidence in this particular area.
Increased skeletal muscle glucose uptake by rosemary extract through AMPK activation
Authors: Naimi Madina , Tsakiridis Theodoros , Stamatatos Theocharis C. , Alexandropoulos Dimitris I. , Tsiani Evangelia
Published: December 2014

Stimulation of the energy sensor AMP-activated kinase (AMPK) has been viewed as a targeted approach to increase glucose uptake by skeletal muscle and control blood glucose homeostasis. Rosemary extract (RE) has been reported to activate AMPK in hepatocytes and reduce blood glucose levels in vivo but its effects on skeletal muscle are not known. In the present study, we examined the effects of RE and the mechanism of regulation of glucose uptake in muscle cells. RE stimulated glucose uptake in L6 myotubes in a dose- and time-dependent manner. Maximum stimulation was seen with 5 μg/mL of RE for 4 h (184% ± 5.07% of control, p < 0.001), a response comparable to maximum insulin (207% ± 5.26%, p < 0.001) and metformin (216% ± 8.77%, p < 0.001) stimulation. RE did not affect insulin receptor substrate 1 and Akt phosphorylation but significantly increased AMPK and acetyl-CoA carboxylase phosphorylation. Furthermore, the RE-stimulated glucose uptake was significantly reduced by the AMPK inhibitor compound C, but remained unchanged by the PI3K inhibitor, wortmannin. RE did not affect GLUT4 or GLUT1 glucose transporter translocation in contrast with a significant translocation of both transporters seen with insulin or metformin treatment. Our study is the first to show a direct effect of RE on muscle cell glucose uptake by a mechanism that involves AMPK activation.
Repeated sprint performance and metabolic recovery curves: effects of aerobic and anaerobic characteristics
Authors: Aguiar Rafael Alves de , Turnes Tiago , Cruz Rogério Santos de Oliveira , Salvador Amadeo Félix , Caputo Fabrizio
Published: December 2014

To examine the influence of aerobic and anaerobic indices on repeated sprint (RS) performance and ability (RSA), 8 sprinters (SPR), 8 endurance runners (END), and 8 active participants (ACT) performed the following tests: (i) incremental test; (ii) 1-min test to determine first decay time constant of pulmonary oxygen uptake off-kinetics and parameters related to anaerobic energy supply, lactate exchange, and removal abilities from blood lactate kinetics; and (iii) RS test (ten 35-m sprints, departing every 20 s) to determine best (RSbest) and mean (RSmean) sprint times and percentage of sprint decrement (%Dec). While SPR had a 98%–100% likelihood of having the fastest RSbest(Cohen’s d of 1.8 and 1.4 for ACT and END, respectively) and RSmean(2.1 and 0.9 for ACT and END, respectively), END presented a 97%–100% likelihood of having the lowest %Dec (0.9 and 2.2 for ACT and SPR, respectively). RSmeanwas very largely correlated with RSbest(r = 0.85) and moderately correlated with estimates of anaerobic energy supply (r = –0.40 to –0.49). RSmeanadjusted for RSbest(which indirectly reflects RSA) was largely correlated with lactate exchange ability (r = 0.55). Our results confirm the importance of locomotor- and anaerobic-related variables to RS performance, and highlight the importance of disposal of selected metabolic by-products to RSA.
Synthesis and application of a novel magnetic metal-organic framework nanocomposite for determination of Cd, Pb, and Zn in baby food samples
Authors: Ghorbani-Kalhor Ebrahim , Hosseinzadeh-Khanmiri Rahim , Babazadeh Mirzaagha , Abolhasani Jafar , Hassanpour Akbar
Published: December 2014

This work describes the synthesis and application of a novel magnetic metal-organic framework (MOF) [(Fe3O4-2,5-dimercapto-1,3,4-thiadiazole)/Cu3(benzene-1,3,5-tricarboxylate)2] to preconcentrate trace amounts of Cd(II), Pb(II), and Zn(II) ions. A Box–Behnken design was used to find the parameters affecting the preconcentration procedure through response surface methodology. Three variables including sorption time, amount of the magnetic sorbent, and sample pH were selected as affecting factors in the sorption step, and four parameters including type, volume, concentration of the eluent, and elution time were selected in the elution step for the optimization study. These values were 33 mg, 11 min, 5.7 EDTA, 4.3 mL, 0.64 mol L–l EDTA solution, 16 min, for amount of the magnetic sorbent, sorption time, sample pH, type, volume, and concentration of the eluent, and elution time, respectively. Following the sorption and elution steps, the ions were quantified by FAAS. The limits of detection were 0.10, 0.15, and 0.75 ng mL−1 for Cd(II), Zn(II), and Pb(II) ions, respectively. The relative standard deviations (RSD) of the method were less than 8.3% for five separate batch experiments in the determination of 25 μg L−1 of Cd(II), Zn(II), and Pb(II) ions. The sorption capacity of the magnetic MOF nanocomposite was 155 mg g−1 for Cd(II), 173 mg g−1 for Pb(II), and 190 mg g−1 for Zn(II). Finally, the magnetic MOF nanocomposite was successfully applied to rapidly extract trace amounts of heavy metal ions in baby food samples.
Influence of soil temperature on growth traits of European beech seedlings
Authors: Štraus Ines , Mrak Tanja , Ferlan Mitja , Železnik Peter , Kraigher Hojka
Published: December 2014

European beech (Fagus sylvatica L.) is an economically and ecologically important forest tree species in Europe. Expected future temperature increases due to global climate change may significantly affect growth of beech trees and consequently influence carbon cycling in beech forests. We tested the hypothesis that soil temperature influences the growth of both belowground and aboveground parts of beech seedlings. One-year-old seedlings were transferred into rhizotrons and subjected to two different soil temperatures for 2 years while the soil moisture level was kept constant. The main effect of the soil temperature was a changed biomass of the woody part of the seedlings. Soil temperature significantly influenced the biomass of shoots and roots and diameter of the stem, which were the highest for the seedlings grown in conditions of soil temperatures maintained in the range of summer soil temperatures from the site of origin of the seedlings. Increased soil temperature also resulted in increased specific root length and specific root tip density. Root-to-shoot ratio and leaf parameters (leaf mass, number of leaves, and specific leaf area), except for leaf area ratio, were not influenced by soil temperature.
An Approximation Method for Blocking Probabilities in M/D/1/K1→ ⋅/D/1/K2Queues
Authors: Seo Dong-Won , Lee Jinpyo , Chang Byeong-Yun
Published: December 2014

Obtaining exact blocking probabilities for tandem queues with finite capacities is not a trivial problem. In this paper, we propose a computational approximation method using max-plus algebra for computing blocking probability in a Poisson-driven 2-node tandem queue with finite capacities and constant service times. The blocking probability of a finite-capacity queueing system can be obtained from either the tail probability of stationary waiting time or the difference between two expected stationary waiting times at the first node of the corresponding extended 3-node tandem queue. The computational results in this study show that the proposed approach provides a good approximation of the blocking probability, and in particular, it works well under moderately to heavily loaded situations. The proposed approach is not limited to a particular blocking policy, system structure, or service time; hence, it is applicable to general queues with finite buffer capacities and various blocking policies.
On characterizing the set of martingale measures in discrete time
Authors: Berkaoui Abdelkarem
Published: December 2014

We state necessary and sufficient conditions on a set of probability measures to be the set of martingale measures for a vector valued, bounded and adapted process. In the absence of the maximality condition, we prove the existence of the smallest set of martingale measures. We apply such results to the finite sample space case.
Framework for a Knowledge Management System for Curriculum Development Process
Authors: Tarnekar Seema A.
Published: December 2014

In this paper, a framework to facilitate development of knowledge management (KM) system for curriculum development process is suggested. It was validated through experts' opinions with thirty two experts. The components of the framework were supported by the experts by emphasizing their necessity and importance in the curriculum development process. Some model curricula and related guidelines were studied to identify components of good curriculum. The curriculum development process was studied through various models for curriculum development proposed by researchers and description of the process by researchers. By the analysis of these models and processes, the Phases in curriculum development process life cycle were identified. Use of knowledge management in business organizations and other disciplines was also studied. Based on all this, this researcher could identify components of a good KM system for curriculum development. This framework will help in implementing a KM system for curriculum development process. It will streamline the process, improve quality of curriculum, save time and efforts by using existing knowledge and avoid repetition of work.
A Framework to Identify Service Quality Determinants of IT Enabled Scalable Ventures: A Study from Indian Context
Authors: Basu Rana , Bhola Prabha
Published: December 2014

The introduction of information and communication technology (ICT) has altered the service delivery around the world by making it more accessible and cost effective across e-service markets. In a country like India the problem of health is an enormous one where a majority of poor are outside the effective medical network. In order to address these problems many information and technology (IT) oriented new ventures have been established to eliminate the gap in health inequity by creating network of hospitals exclusively in non-urban areas. Despite of huge popularity of these services, identifying the quality of such services need careful attention. Exhaustive review of literature highlights that there exists little understanding for such a study in IT enabled Indian healthcare domain in context to new ventures/start-ups with an emergence of a gap. With the increasing rise of technology enabled new healthcare ventures there have been high rates of failure too due to lack of providing quality service, so it has become imperative to prioritize the contextual and sectoral specific settings of service quality issues as it is being felt increasingly that it is the quality that would ultimately decide the value of services. This paper thus attempts to prioritize the context specific service quality dimensions in IT enabled scalable healthcare ventures from Indian context with focus in non-urban regions by deploying technique for order preference by similarity to ideal solution (TOPSIS) methodology as multi-criteria decision making technique. Further this paper proposed a conceptual model as conjectural understanding of the antecedents to the start-ups and as a guide that can provides new entrepreneurial insights to the service managers who can better apportion their resource in order to build quality and scalability.
Cryptocurrencies, smart contracts, and artificial intelligence
Authors: Omohundro Steve
Published: December 2014

Recent developments in "cryptocurrencies" and "smart contracts" are creating new opportunities for applying AI techniques. These economic technologies would benefit from greater real world knowledge and reasoning as they become integrated with everyday commerce. Cryptocurrencies and smart contracts may also provide an infrastructure for ensuring that AI systems follow specified legal and safety regulations as they become more integrated into human society.
Simulated Annealing Technique for Routing in a Rectangular Mesh Network
Authors: Adzhar Noraziah , Salleh Shaharuddin
Published: December 2014

In the process of automatic design for printed circuit boards (PCBs), the phase following cell placement is routing. On the other hand, routing process is a notoriously difficult problem, and even the simplest routing problem which consists of a set of two-pin nets is known to be NP-complete. In this research, our routing region is first tessellated into a uniformNx×Nyarray of square cells. The ultimate goal for a routing problem is to achieve complete automatic routing with minimal need for any manual intervention. Therefore, shortest path for all connections needs to be established. While classical Dijkstra’s algorithm guarantees to find shortest path for a single net, each routed net will form obstacles for later paths. This will add complexities to route later nets and make its routing longer than the optimal path or sometimes impossible to complete. Today’s sequential routing often applies heuristic method to further refine the solution. Through this process, all nets will be rerouted in different order to improve the quality of routing. Because of this, we are motivated to apply simulated annealing, one of the metaheuristic methods to our routing model to produce better candidates of sequence.