bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns of angiotensin converting enzyme insertion/deletion gene polymorphism among an Egyptian cohort of patients with rheumatoid arthritis
Authors: Ahmed Afaf Z. , El‐Shahaly Hassan A. , Omar Aziza S. , Ghattas Maivel H.
Published: September 2012

Aim

This case control study was designed to determine the patterns of angiotensin converting enzyme insertion/deletion (ACE I/D) gene polymorphism in rheumatoid arthritis (RA) patients and healthy controls.

Methods

The study population was divided into two groups: the study group included 66 RA patients diagnosed according to the American College of Rheumatology (ACR) classification criteria for RA, and the control group included 66 healthy adults who were age‐and sex‐matched to the RA group. All RA patients were assessed by Disease Activity Score (DAS28), ACR Classification of Global Functional Disability Status and Sharp's score as outcome measures. Gene investigations for ACE I/D polymorphism were performed by polymerase chain reaction (PCR) in both groups.

Results

The ACE I/D polymorphism was the (D/D) genotype in 60.6% (n = 40) of RA patients, the (I/D) genotype in 31.8% (n = 21) and the (I/I) genotype in 7.6% (n = 5). The frequency of (D) carriage was significantly higher in the RA cases than in the control group (76.5% vs. 53.8%, respectively, P = 0.0002). ACE D allele carriers were at higher risk of RA, 2.8 times higher than (I) carriers and those who had the homozygote (DD) genotype had 5.6 times the possibility of having RA. No correlations were observed between the homozygote (DD) genotype and disease activity or severity in RA patients.

Conclusions

Our study suggests that high frequency of the ACE D allele contributes to the heritability of RA susceptibility compared to other ACE alleles. On the other hand, no association was detected between ACE I/D polymorphism and the severity of RA.
Effects of branched‐chain amino acid granules on serum albumin level and prognosis are dependent on treatment adherence in patients with liver cirrhosis
Authors: Takaguchi Koichi , Moriwaki Hisataka , Doyama Hisashi , Iida Masayuki , Yagura Michiyasu , Shimada Noritomo , Kang Masahiro , Yamada Haruki , Kumada Hiromitsu
Published: September 2012

Aim

To test if the treatment adherence to branched‐chain amino acid (BCAA) granules influences the serum albumin level and prognosis in prospective 2984 patients with decompensated liver cirrhosis who were prescribed BCAA granules containing 952 mg of L‐isoleucine, 1904 mg of L‐leucine and 1144 mg of L‐valine at 4.15 g/sachet three times a day after meals.

Methods

The primary end‐point was the time to the event defined as “hospital admission due to progression of hepatic failure”, and factors affecting this outcome were explored. Changes in serum albumin level were evaluated as the secondary end‐point.

Results

Patients were divided into the good adherence group (those who reported to have taken “nearly all” prescribed doses) and the poor adherence group (those who reported to have taken “approximately half” or “less” doses), because such stratification was validated by treatment responses in plasma BCAA/tyrosine ratio. Factors related to the primary end‐point were age, drug adherence during 6 months of study treatment, previous hepatic cancer, current clinical manifestations, previous clinical manifestations, baseline serum albumin level, platelet count and total bilirubin level. The cumulative event‐free survival was significantly higher in the good adherence group. Increase in the serum albumin level was also greater in the good adherence group.

Conclusion

Higher BCAA treatment adherence better raised the serum albumin level, leading to improvement of event‐free survival. These results indicate the importance of patient instruction for the adequate use of BCAA granules.
Comparison of epirubicin hydrochloride and miriplatin hydrate as anticancer agents for transcatheter arterial chemoembolization of hepatocellular carcinoma
Authors: Aramaki Takeshi , Moriguchi Michihisa , Bekku Emima , Asakura Kouiku , Sawada Akihiro , Endo Masahiro
Published: September 2012

Aim

The aim of this retrospective study was to compare the local control effects of transcatheter arterial chemoembolization (TACE) using epirubicin (EPIR) and that using miriplatin (MPT) for hepatocellular carcinoma (HCC).

Methods

Between January 2010 and July 2011, 218 HCC cases were treated with TACE, including 69 cases using EPIR or MPT as initial treatment. All 69 patients were treated with iodized oil and gelatin sponge particles. The local control rate (modified Response Evaluation Criteria in Solid Tumors [RECIST] ver. 1.0), time to treatment failure (Kaplan–Meier and log–rank test) and adverse events were evaluated.

Results

Forty‐two cases were treated using EPIR, and 27 cases were treated using MPT. All 69 patients had no previous treatment with TACE or hepatic arterial infusion. No serious adverse events were observed in either group. The response rates, including complete response (CR) and partial response (PR), of the EPIR group and the MPT group were 85.7% and 81.5%, respectively, with a time to treatment failure of 5.1 and 7.5 months, respectively. Excluding whole liver TACE cases, time to treatment failure was 5.4 months for the EPIR group and 10.1 months for the MPT group.

Conclusion

In TACE naïve cases, there was no significant difference in local control between EPIR and MPT.
NEWTON AND WOLFF: THE LEIBNIZIAN REACTION TO THE PRINCIPIA, 1716–1763
Authors: STAN MARIUS
Published: September 2012

abstract

Newton rested his theory of mechanics on distinct metaphysical and epistemological foundations. After Leibniz's death in 1716, the Principia ran into sharp philosophical opposition from Christian Wolff and his disciples, who sought to subvert Newton's foundations or replace them with Leibnizian ideas. In what follows, I chronicle some of the Wolffians' reactions to Newton's notion of absolute space, his dynamical laws of motion, and his general theory of gravitation. I also touch on arguments advanced by Newton's Continental followers, such as Leonhard Euler, who made novel attempts to defend his mechanical foundations against the pro‐Leibnizian attack. This examination grants us deeper insight into the fate of Newton's mechanics on the Continent during the early eighteenth century and, more specifically, sheds needed light on the conflicts and tensions that characterized the reception of Newton's philosophy of mechanics among the Leibnizians.
Time‐of‐flight magnetic resonance angiography (TOF‐MRA) of the normal equine head
Authors: MANSO‐DÍAZ G. , GARCÍA‐REAL M. I. , CASTELEYN C. , SAN‐ROMÁN F. , TAEYMANS O.
Published: September 2012

Reasons for performing study: Noncontrast magnetic resonance angiography (MRA) is widely used in human and small animal medicine. However, this technique has not yet been described in the horse, and compared to other angiographic techniques MRA could be more cost efficient and potentially safer.

Objectives: The aim of this study was to provide a comprehensive anatomical reference of the normal equine head vasculature using a noncontrast MRA technique, on both low‐ and high‐field MRI.

Methods: Five healthy adult horses were examined, 4 with a low‐field magnet (0.23T) and the remaining one with a high‐field magnet (1.5T). The magnetic resonance angiography sequence used was TOF (time‐of‐flight) 2D‐MRA and CT images of a vascular corrosion cast were subsequently used as anatomical references.

Results: The MRA imaging protocol provided good visualisation of all major intra‐ and extracranial vessels down to a size of approximately 2 mm in diameter on both low‐ and high‐field systems. This resulted in identification of vessels to the order of 3rd–4th branches of ramification. The visibility of the arteries was higher than of the veins, which showed lower signal intensity. Overall, MRA obtained with the high‐field protocol provided better visualisation of the arteries, showing all the small arterial branches with a superior resolution.

Conclusions: The use of a specific vascular sequence such as TOF 2D‐MRA allows good visualisation of the equine head vasculature and eliminates the need for contrast media for MRA.

Potential relevance: Magnetic resonance angiography allows for visualisation of the vasculature of the equine head. Vessel morphology, symmetry and size can be evaluated and this may possibly play a role in preoperative planning or characterisation of diseases of the head, such as neoplasia or guttural pouch mycosis.
Experiences of poststroke fatigue: qualitative meta‐synthesis
Authors: Eilertsen Grethe , Ormstad Heidi , Kirkevold Marit
Published: September 2012

Aim

To interpret and synthesize stroke survivors' experiences of poststroke fatigue.

Background

Several studies have found fatigue to be a common and distressing difficulty experienced after stroke. This review has synthesized qualitative findings of stroke survivors' experiences of poststroke fatigue with the aim of guiding practice and further research.

Data sources

A computer‐aided search of the PubMed, CINAHL, PsycINFO, and Embase databases was performed up to April 2012.

Design and review methods

Interpretive qualitative meta‐synthesis. Of 167 papers identified, 12 were included.

Findings

Three main themes of the experience of poststroke fatigue were identified. First, five characteristics were identified and interpreted as core characteristics of poststroke fatigue. These did not seem to be influenced by the context. Two additional, distressing characteristics were identified. These were interpreted as being more responsive to the context. Second, we found that the acknowledgement of poststroke fatigue by stroke survivors and their significant others were important for the experience of poststroke fatigue. This theme appeared to be consistent across studies and was interpreted as having a major impact on the third theme identified; coping with poststroke fatigue. Two main coping patterns appeared: one taking the fatigue into account and the other struggling to cope. Lack of acknowledgement of poststroke fatigue complicates the coping process and invokes additional emotional distress.

Conclusion

Poststroke fatigue is a complex phenomenon. Acknowledging its presence and impact is important to cope well with it. Lack of acknowledgement from significant others increases add to the burden.

[Correction added after online publication 3 September 2012: Instances of the word ‘statistically’ have been removed from the Findings and Conclusion in the abstract section.]
Physiological, biochemical and molecular responses to a combination of drought and ozone in Medicago truncatula
Authors: IYER NIRANJANI J. , TANG YUHONG , MAHALINGAM RAMAMURTHY
Published: September 2012

Drought and tropospheric ozone are escalating climate change problems that can co‐occur. In this study, we observed Medicago truncatula cultivar Jemalong that is sensitive to ozone and drought stress when applied singly, showed tolerance when subjected to a combined application of these stresses. Lowered stomatal conductance may be a vital tolerance mechanism to overcome combined ozone and drought. Sustained increases in both reduced ascorbate and glutathione in response to combined stress may play a role in lowering reactive oxygen species and nitric oxide toxicity. Transcriptome analysis indicated that genes associated with glucan metabolism, responses to temperature and light signalling may play a role in dampening ozone responses due to drought‐induced stomatal closure during combined occurrence of these two stresses. Gene ontologies for jasmonic acid signalling and innate immunity were enriched among the 300 differentially expressed genes unique to combined stress. Differential expression of transcription factors associated with redox, defence signalling, jasmonate responses and chromatin modifications may be important for evoking novel gene networks during combined occurrence of drought and ozone. The alterations in redox milieu and distinct transcriptome changes in response to combined stress could aid in tweaking the metabolome and proteome to annul the detrimental effects of ozone and drought in Jemalong.
The WOX13 homeobox gene promotes replum formation in the Arabidopsis thaliana fruit
Authors: Romera‐Branchat Maida , Ripoll Juan José , Yanofsky Martin F. , Pelaz Soraya
Published: September 2012

The Arabidopsis fruit forms a seedpod that develops from the fertilized gynoecium. It is mainly comprised of an ovary in which three distinct tissues can be differentiated: the valves, the valve margins and the replum. Separation of cells at the valve margin allows for the valves to detach from the replum and thus dispersal of the seeds. Valves and valve margins are located in lateral positions whereas the replum is positioned medially and retains meristematic properties resembling the shoot apical meristem (SAM). Members of the WUSCHEL‐related homeobox family have been involved in stem cell maintenance in the SAM, and within this family, we found that WOX13 is expressed mainly in meristematic tissues including the replum. We also show that wox13 loss‐of‐function mutations reduce replum size and enhance the phenotypes of mutants affected in the replum identity gene RPL. Conversely, misexpression of WOX13 produces, independently from BP and RPL, an oversized replum and valve defects that closely resemble those of mutants in JAG/FIL activity genes. Our results suggest that WOX13 promotes replum development by likely preventing the activity of the JAG/FIL genes in medial tissues. This regulation seems to play a role in establishing the gradient of JAG/FIL activity along the medio‐lateral axis of the fruit critical for proper patterning. Our data have allowed us to incorporate the role of WOX13 into the regulatory network that orchestrates fruit patterning.
Age‐related influence of vision and proprioception on Ia presynaptic inhibition in soleus muscle during upright stance
Authors: Baudry Stéphane , Duchateau Jacques
Published: September 2012

Key points

The observed decrease in balance with ageing, vision suppression and compliance of the support surface may involve differential modulation of Ia afferent feedback from leg muscles.

The modulation of Ia presynaptic inhibition for the soleus muscle was assessed in young and elderly adults when standing in normal and modified visual (eyes closed) and proprioceptive conditions (foam support).

The results suggest that presynaptic inhibition of Ia afferents increased when vision was suppressed and when standing on a foam mat, but more so in elderly adults, for whom the increase in Ia presynaptic inhibition was associated with greater activity of the leg muscles.

Young and elderly adults appear to rely less on segmental muscle afferent feedback to control the activation of leg muscles during upright stance when vision and proprioception are altered.

Abstract  This study investigated the modulation of Ia afferent input in young and elderly adults during quiet upright stance in normal and modified visual and proprioceptive conditions. The surface EMG of leg muscles, recruitment curve of the soleus (SOL) Hoffmann (H) reflex and presynaptic inhibition of Ia afferents from SOL, assessed with the D1 inhibition and single motor unit methods, were recorded when young and elderly adults stood with eyes open or closed on two surfaces (rigid vs. foam) placed over a force platform. The results showed that elderly adults had a longer path length for the centre of pressure and larger antero‐posterior body sway across balance conditions (P < 0.05). Muscle EMG activities were greater in elderly compared with young adults (P < 0.05), whereas the Hmax expressed as a percentage of the Hmax was lower (P = 0.048) in elderly (38 ± 16%) than young adults (58 ± 16%). The conditioned H reflex/test H reflex ratio (D1 inhibition method) increased with eye closure and when standing on foam (P < 0.05), with greater increases for elderly adults (P = 0.019). These changes were accompanied by a reduced peak motor unit discharge probability when standing on rigid and foam surfaces (P ≤ 0.001), with a greater effect for elderly adults (P = 0.026). Based on these latter results, the increased conditioned H reflex/test H reflex ratio in similar sensory conditions is likely to reflect occlusion at the level of presynaptic inhibitory interneurones. Together, these findings indicate that elderly adults exhibit greater modulation of Ia presynaptic inhibition than young adults with variation in the sensory conditions during upright standing.
Vestibular‐mediated synaptic inputs and pathways to sympathetic preganglionic neurons in the neonatal mouse
Authors: Kasumacic Nedim , Glover Joel C. , Perreault Marie‐Claude
Published: September 2012

Key points

When the body is tilted from horizontal to vertical, blood tends to accumulate in the legs, and blood pressure may fall in the upper body and head, a phenomenon known as orthostatic hypotension.

The vestibulosympathetic reflexes triggered by stimulation of vestibular afferents help to counteract orthostatic hypotension, especially during its initial onset.

We used anex vivopreparation of the brainstem and spinal cord of the neonatal mouse, and high‐throughput optical recording to assess when vestibulosympathetic projections become functional postnatally.

Vestibulosympathetic synaptic connections are present in the mouse, and are already functional at birth. The organization of the projections includes many of the key features seen in adult mammals.

The demonstration of similarity between vestibulosympathetic pathways in mice and other mammals is exciting because mouse models provide the possibility to use powerful molecular genetic techniques to make discoveries that may be very relevant for human vestibulo‐autonomic dysfunction.

Abstract To assess when vestibulosympathetic projections become functional postnatally, and to establish a preparation in which vestibulosympathetic circuitry can be characterized more precisely, we used an optical approach to record VIIIth nerve‐evoked synaptic inputs to thoracic sympathetic preganglionic neurons (SPNs) in newborn mice. Stimulation of the VIIIth nerve was performed in an isolated brainstem–spinal cord preparation after retrogradely labelling with the fluorescent calcium indicator Calcium Green 1‐conjugated dextran amine, the SPNs and the somatic motoneurons (MNs) in the thoracic (T) segments T2, 4, 6, 8, 10 and 12. Synaptically mediated calcium responses could be visualized and recorded in individual SPNs and MNs, and analysed with respect to latency, temporal pattern, magnitude and synaptic pharmacology. VIIIth nerve stimulation evoked responses in all SPNs and MNs investigated. The SPN responses had onset latencies from 90 to 200 ms, compared with much shorter latencies in MNs, and were completely abolished by mephenesin, a drug that preferentially reduces polysynaptic over monosynaptic transmission. Bicuculline and picrotoxin, but not strychnine, increased the magnitudes of the SPN responses without changing the onset latencies, suggesting a convergence of concomitant excitatory and inhibitory synaptic inputs. Lesions strategically placed to test the involvement of direct vestibulospinal pathwaysversusindirect pathways within the brainstem showed that vestibulosympathetic inputs in the neonate are mediated predominantly, if not exclusively, by the latter. Thus, already at birth, synaptic connections in the vestibulosympathetic reflex are functional and require the involvement of the ventrolateral medulla as in adult mammals.
Low‐fidelity GABA transmission within a dense excitatory network of the solitary tract nucleus
Authors: McDougall Stuart J. , Andresen Michael C.
Published: September 2012

Key points

Successful transmission of information to the brain relies on a balance of excitation and inhibition, and this balance is different across different brain regions.

In the brain areas responsible for initiating homeostatic reflex control of visceral organs, excitation is known to be particularly powerful whereas inhibition is often less obvious.

Using minimal focal activation of single axons, this study shows that elementary inhibitory transmission in this brainstem region is founded on an intrinsically weak process with limited transmitter release that is surprisingly prone to failures.

Strong inhibitory transmission requires multi‐axon convergence of modestly reliable synapses, whereas primary afferent excitation arises from single, multi‐contact axons with highly reliable neurotransmitter release.

The results suggest that the entry of primary afferent information along cranial nerves enjoys a high safety factor in part due to the fundamental weakness of inhibitory transmission at these initial central neurons.

Abstract Visceral primary afferents enter the CNS at the caudal solitary tract nucleus (NTS), and activate central pathways key to autonomic and homeostatic regulation. Excitatory transmission from primary solitary tract (ST)‐afferents consists of multiple contacts originating from single axons that offer a remarkably high probability of glutamate release and high safety factor for ST afferent excitation. ST afferent activation sometimes triggers polysynaptic GABAergic circuits, which feedback onto second‐order NTS neurons. Although inhibitory transmission is observed at second‐order neurons, much less is known about the organization and mechanisms regulating GABA transmission. Here, we used a focal pipette to deliver minimal stimulus shocks near second‐order NTS neurons in rat brainstem slices and directly activated single GABAergic axons. Most minimal focal shocks activated low jitter EPSCs from single axons with characteristics resembling ST afferents. Much less commonly (9% of sites), minimal focal shocks activated monosynaptic IPSCs at fixed latency (low jitter) that often failed (30%) and had no frequency‐dependent facilitation or depression. These GABA release characteristics contrasted markedly to the unfailing, large amplitudes for glutamate released during ST‐EPCSs recorded from the same neurons. Surprisingly, unitary GABAergic IPSCs were only weakly calcium dependent. In some neurons, strong focal shocks evoked compound IPSCs indicating convergent summation of multiple inhibitory axons. Our studies demonstrate that second‐order NTS neurons receive GABAergic transmission from a diffuse network of inhibitory axons that rely on an intrinsically less reliable and substantially weaker release apparatus than ST excitation. Effective inhibition depends on co‐activation of convergent inputs to blunt excitatory drive.
Load Calculation and Life Prediction for Auto Water Pump Bearing
Authors: Li Zhengmei , Zhou Qiong , Tang Jianping , Wang Jianwen , An Qi
Published: September 2012

Taking the water pump bearing with one roller row (WR)-type auto water pump bearing as a research sample, an analytical calculation method is developed to improve the accuracy and efficiency of the current calculations for the bearing loads and life in engineering application. Considering the misalignment due to the deflection of the bearing spindle, the bearing internal loads and deformations under the action of the complicated external space loads are obtained. The bearing fatigue life including the lives of the rollers and the balls is also calculated with considering the non-normal load distribution caused by the spindle deflection and the roller tilt. The bearing load and life calculation results are compared with those calculated by the traditional method in which the deflection of the bearing spindle and the roller tilt are ignored. The effects of the bearing spindle deflection on the load distribution and the life of the auto water pump bearing are analyzed and discussed. The life decrease in the auto water pump bearing is significant due to the deflection of the bearing spindle and it is recommended to give more attention to this deflection for the high quality of the bearing design and calculation.
Measurements of Losses and Reynolds Stresses in the Secondary Flow Downstream of a Low-Speed Linear Turbine Cascade
Authors: MacIsaac G. D. , Sjolander S. A. , Praisner T. J.
Published: September 2012

Experimental measurements of the mean and turbulent flow field were preformed downstream of a low-speed linear turbine cascade. The influence of turbulence on the production of secondary losses is examined. Steady pressure measurements were collected using a seven-hole pressure probe and the turbulent flow quantities were measured using a rotatable x-type hotwire probe. Each probe was traversed downstream of the cascade along planes positioned at three axial locations: 100%, 120%, and 140% of the axial chord (Cx) downstream of the leading edge. The seven-hole pressure probe was used to determine the local total and static pressure as well as the three mean velocity components. The rotatable x-type hotwire probe, in addition to the mean velocity components, provided the local Reynolds stresses and the turbulent kinetic energy. The axial development of the secondary losses is examined in relation to the rate at which mean kinetic energy is transferred to turbulent kinetic energy. In general, losses are generated as a result of the mean flow dissipating kinetic energy through the action of viscosity. The production of turbulence can be considered a preliminary step in this process. The measured total pressure contours from the three axial locations (1.00, 1.20, and 1.40Cx) demonstrate the development of the secondary losses. The peak loss core in each plane consists mainly of low momentum fluid that originates from the inlet endwall boundary layer. There are, however, additional losses generated as the flow mixes with downstream distance. These losses have been found to relate to the turbulent Reynolds stresses. An examination of the turbulent deformation work term demonstrates a mechanism of loss generation in the secondary flow region. The importance of the Reynolds shear stresses to this process is explored in detail.
Study of Ductile-to-Brittle Transition in Single Grit Diamond Scribing of Silicon: Application to Wire Sawing of Silicon Wafers
Authors: Wu Hao , Melkote Shreyes N.
Published: September 2012

The ductile-to-brittle cutting mode transition in single grit diamond scribing of monocrystalline silicon is investigated in this paper. Specifically, the effects of scriber tip geometry, coefficient of friction, and external hydrostatic pressure on the critical depth of cut associated with ductile-to-brittle transition and crack generation are studied via an eXtended Finite Element Method (XFEM) based model, which is experimentally validated. Scribers with a large tip radius are shown to produce lower tensile stresses and a larger critical depth of cut compared with scribers with a sharp tip. Spherical tipped scribers are shown to generate only surface cracks, while sharp tipped scribers (conical, Berkovich and Vickers) are found to create large subsurface tensile stresses, which can lead to nucleation of subsurface median/lateral cracks. Lowering the friction coefficient tends to increase the critical depth of cut and hence the extent of ductile mode cutting. The results also show that larger critical depth of cut can be obtained under external hydrostatic pressure. This knowledge is expected to be useful in optimizing the design and application of the diamond coated wire employed in fixed abrasive diamond wire sawing of photovoltaic silicon wafers.
Heat Transfer and Friction Augmentation in High Aspect Ratio, Ribbed Channels With Dissimilar Inlet Conditions
Authors: Slabaugh Carson D. , Tran Lucky V. , Kapat J. S. , Warren Bobby A.
Published: September 2012

This work is an investigation of the heat transfer and pressure-loss characteristics in a rectangular channel with ribs oriented perpendicular to the flow. The novelty of this study lies in the immoderate parameters of the channel geometry and transport enhancing features. Specifically, the aspect ratio (AR) of the rectangular channel is considerably high, varying from 15 to 30 for the cases reported. Also varied is the rib-pitch to rib-height (p/e), studied at two values, 18.8 and 37.3. Rib-pitch to rib-width (p/w) is held to a value of two for all configurations. Channel Reynolds number is varied between approximately 3000 and 27,000 for four different tests of each channel configuration. Each channel configuration is studied with two different inlet conditions. The baseline condition consists of a long entrance section leading to the entrance of the channel to provide a hydrodynamically developed flow at the inlet. The second inlet condition studied consists of a cross-flow supply in a direction perpendicular to the channel axis, oriented in the direction of the channel width (the longer channel dimension). In the second case, the flow rate of the cross-flow supply is varied to understand the effects of a varying momentum flux ratio on the heat transfer and pressure-loss characteristics of the channel. Numerical simulations revealed a strong dependence of the local flow physics on the momentum flux ratio. The turning effect of the flow entering the channel from the cross-flow channel is strongly affected by the pressure gradient across the channel. Strong pressure fields have the ability to propagate farther into the cross-flow channel to “pull” the flow, partially redirecting it before entering the channel and reducing the impingement effect of the flow on the back wall of the channel. Experimental results show a maximum value of Nusselt number augmentation to be found in the 30:1 AR channel with the aggressive augmenter (p/e = 37.3) and a high momentum flux ratio: Nu/Nuo = 3.15. This design also yielded the friction with f/f0 = 2.6.
Analysis of Flutter-Induced Limit Cycle Oscillations in Gas-Turbine Structures With Friction, Gap, and Other Nonlinear Contact Interfaces
Authors: Petrov E. P.
Published: September 2012

A frequency-domain method has been developed to predict and comprehensively analyze the limit-cycle flutter-induced vibrations in bladed disks and other structures with nonlinear contact interfaces. The method allows, for the first time, direct calculation of the limit-cycle amplitudes and frequencies as functions of contact interface parameters and aerodynamic characteristics using realistic large-scale finite element models of structures. The effects of the parameters of nonlinear contact interfaces on limit-cycle amplitudes and frequencies have been explored for major types of nonlinearities occurring in gas-turbine structures. New mechanisms of limiting the flutter-induced vibrations have been revealed and explained.
Analysis of Unsteady Flows Past Horizontal Axis Wind Turbine Airfoils Based on Harmonic Balance Compressible Navier-Stokes Equations With Low-Speed Preconditioning
Authors: Campobasso M. Sergio , Baba-Ahmadi Mohammad H.
Published: September 2012

This paper presents the numerical models underlying the implementation of a novel harmonic balance compressible Navier-Stokes solver with low-speed preconditioning for wind turbine unsteady aerodynamics. The numerical integration of the harmonic balance equations is based on a multigrid iteration, and, for the first time, a numerical instability associated with the use of such an explicit approach in this context is discussed and resolved. The harmonic balance solver with low-speed preconditioning is well suited for the analyses of several unsteady periodic low-speed flows, such as those encountered in horizontal axis wind turbines. The computational performance and the accuracy of the technology being developed are assessed by computing the flow field past two sections of a wind turbine blade in yawed wind with both the time-and frequency-domain solvers. Results highlight that the harmonic balance solver can compute these periodic flows more than 10 times faster than its time-domain counterpart, and with an accuracy comparable to that of the time-domain solver.
Turbine Hub and Shroud Sealing Flow Loss Mechanisms
Authors: Zlatinov Metodi Blagoev , Sooi Tan Choon , Montgomery Matthew , Islam Tito , Harris Melissa
Published: September 2012

Purge air is injected through seals in the hub and shroud of axial turbines in order to prevent hot gas ingestion into the inter-stage gaps. An investigation into the losses involved with the injection of purge air has been undertaken, with the objectives of answering where the losses are generated, how they are generated, and what are the most effective ways for reducing them. In order to address these questions, a consistent framework for interpreting entropy generation as a measure of loss is developed for turbomachinery applications with secondary air streams. A procedure for factoring out distinct effects is also presented. These tools, applied to steady computations, elucidate four mechanisms by which change in loss generation is brought about due to injection of purge air: a shear layer between purge and main streams, interaction with the passage vortex system that generates radial velocity gradients, changes in wetted loss and tip clearance flow due to an increased degree of reaction, and the potential for reducing tip clearance flow for the case of purge flow injected from the shroud. An emphasis is placed on tracing these effects to specific purge flow characteristics that drive them. The understanding gained provides a rationale for the observed sensitivity of purge flow losses to the design parameters purge air mass fraction and swirl, compared to purge slot axial inclination and gap width. Preswirling of purge flow is less effective in mitigating losses in the case of shroud-injection, since there is a tradeoff with the tip clearance flow suppression effect.
Low Pressure Turbine Secondary Vortices: Reynolds Lapse
Authors: Kuerner Matthias , Reichstein Georg A. , Schrack Daniel , Rose Martin G. , Staudacher Stephan , Gier Jochen , Engel Karl
Published: September 2012

A two-stage turbine is tested in a cooperation between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines GmbH (MTU). The experimental results taken in the Altitude Test Facility (ATF) are used to assess the impact of cavity flow and leakage on vortex structures. The analysis focuses on a range of small Reynolds numbers, from as low as 35,000 up to 88,000. The five hole probe area traverse data is compared to steady multistage CFD predictions behind the second vane. The numerical model compares computations without and with cavities modeled. The simulation with cavities is superior to the approach without cavities. The vortex induced blockage is found to be inversely proportional to the Reynolds number. The circulation of the vortices is dependent on the Reynolds number showing a reversing trend to the smallest Reynolds numbers. The steady numerical model as of yet is unsuitable to predict these trends. A first unsteady simulation suggests major improvements.
Numerical Investigation of Low Solidity Vaned Diffuser Performance in a High-Pressure Centrifugal Compressor—Part III: Tandem Vanes
Authors: Oh JongSik , Buckley Charles W. , Agrawal Giri L.
Published: September 2012

As Part III, following the authors’ previous studies, the aerodynamic performance of two different tandem LSDs (low solidity diffusers), Tandem (A) and (B), in a high-pressure centrifugal compressor was numerically investigated over flow rates from impeller choke to minimal flows available in computation. Tandem (A) was of conventional design where the first row came directly from the authors’ previous studies (Part I Oh and Agrawal, 2007, “Numerical Investigation of Low Solidity Vaned Diffuser Performance in a High-Pressure Centrifugal Compressor - Part I : Influence of Vane Solidity,” ASME Paper No. GT2007-27260, and Part II: Oh et al., 2008, “Numerical Investigation of Low Solidity Vaned Diffuser Performance in a High-Pressure Centrifugal Compressor - Part II : Influence of Vane Stagger,” ASME Paper No. GT2008-50178) selected as the highest efficiency vane at design flow, and the second row was designed to be added considering flow conditions at the exit of the first row vane. Tandem (B) followed a creative patent-pending concept where the number of the first row vanes was doubled with much smaller vane chord keeping a low solidity. A position parameter of RCP (relative circumferential position) was introduced to see the effect of the relative location of the second row vane. Using an in-house Navier-Stokes solver with finite volume time marching methods, overall performance was predicted to be compared with each other. Detailed investigation on the behavior of the static pressure recovery and the total pressure loss coefficient in both diffuser designs helps determine why Tandem (A) design is better and the case of RCP = 0.3 gives the best performance.
Particle Image Velocimetry Analysis on the Effect of Stator Loading on Transonic Blade-Row Interactions
Authors: Reynolds Scott B. , Gorrell Steven E. , Estevadeordal Jordi
Published: September 2012

Experiments were performed to investigate interactions between a loaded stator and transonic rotor. The blade row interaction (BRI) rig was used to simulate an embedded transonic fan stage with realistic geometry (thin trailing edge), which produces a wake through diffusion. Details of the unsteady flow field between the stator and rotor were obtained using PIV. Flow-visualization images and PIV data that facilitate analysis of vortex shedding, wake motion, and wake-shock-interaction phenomena are presented. Stator wake and rotor-bow-shock interactions were analyzed for three stator/rotor axial spacings and two stator loadings. Specific shed vortices and wake topological features were isolated for each configuration. The data analysis focuses on measuring the vortex size, strength, and location as it forms on the stator trailing edge and propagates downstream into the rotor passage. It was observed that vortex shedding is synchronized to the passing of a rotor bow shock. Results show that the circulation of a vortex increased by 19% to 23% from far to close spacing due to the increased strength of the rotor bow shock impacting the stator trailing edge. Reduction in stator loading decreased shed vortex circulation for the same stator/rotor axial spacing by 20% to 25%. Pitchwise radius of vortices also decreased by 13% to 19% from far to close spacing. Such changes in vortex size and strength should be accounted for to predict the effect of unsteady blade-row interactions on transonic compressor performance.
On Shil’nikov Analysis of Homoclinic and Heteroclinic Orbits of the T System
Authors: Algaba Antonio , Fernández-Sánchez Fernando , Merino Manuel , Rodríguez-Luis Alejandro J.
Published: September 2012

In the referenced paper, the authors use the undetermined coefficient method to analytically construct homoclinic and heteroclinic orbits in the T system. Unfortunately their method is not valid because they assume odd functions for the first component of the homoclinic and the heteroclinic orbit whereas these Shil'nikov global connections do not exhibit symmetry.
A Generalized Component Mode Synthesis Approach for Flexible Multibody Systems With a Constant Mass Matrix
Authors: Pechstein Astrid , Reischl Daniel , Gerstmayr Johannes
Published: September 2012

A standard technique to reduce the system size of flexible multibody systems is the component mode synthesis. Selected mode shapes are used to approximate the flexible deformation of each single body numerically. Conventionally, the (small) flexible deformation is added relatively to a body-local reference frame which results in the floating frame of reference formulation (FFRF). The coupling between large rigid body motion and small relative deformation is nonlinear, which leads to computationally expensive nonconstant mass matrices and quadratic velocity vectors. In the present work, the total (absolute) displacements are directly approximated by means of global (inertial) mode shapes, without a splitting into rigid body motion and superimposed flexible deformation. As the main advantage of the proposed method, the mass matrix is constant, the quadratic velocity vector vanishes, and the stiffness matrix is a co-rotated constant matrix. Numerical experiments show the equivalence of the proposed method to the FFRF approach.
A New Extended Multiple Car-Following Model Considering the Backward-Looking Effect on Traffic Flow
Authors: Yang Shuhong , Liu Weining , Sun Dihua , Li Chungui
Published: September 2012

To make full use of the newly available information provided by the intelligent transportation system (ITS), we presented a new car-following model applicable to automated driving control, which will be realized in the near future along with the rapid development of ITS. In this model, the backward-looking effect and the information inputs from multiple leading cars in traffic flow are considered at the same time. The linear stability criterion of this model is obtained using linear stability theory. Furthermore, the nonlinear analysis method is employed to derive the modified Korteweg-de Vries (mKdV) equation, whose kink-antikink soliton solution is then used to describe the occurrence of traffic jamming transitions. The numerical simulation of the presented model is carried out. Both the analytical analysis and numerical simulation show that the traffic jam is suppressed efficiently by just considering the information of two leading cars and a following one.
Giant mesenteric cyst: a rare cause of abdominal distension diagnosed with CT and managed with ultrasound-guided drainage
Authors: Ma Alexander , Ayre Karyn , Wijeyekoon Sanjaya
Published: September 2012

This rare cystic lesion has an approximate incidence of 1 in 200 000. This patient complained of abdominal distension and was diagnosed with a giant mesenteric cyst measuring 26 cm in height using CT imaging. She underwent a successful ultrasound-guided drainage, which is not previously reported in the literature. This represents utilisation of an established procedure in a novel situation.
Paradoxical reaction to antitubercular therapy in miliary tuberculosis
Authors: Gupta Ankush , Srivastava Vijay Kumar , Khanna Vibhu Narain , Rizvi Imran
Published: September 2012

An 18-year-old boy presented with fever, weight loss and loss of appetite for 6 months duration. Investigation revealed raised erythrocyte sedimentation rate, negative sputum smear examination for acid-fast bacilli, x-ray and high-resolution CT chest showed bilateral, diffuse infiltration of lung parenchyma with miliary shadows. The patient was treated as a case of miliary tuberculosis with antitubercular therapy (ATT). On the 10th day of treatment the patient developed high-grade fever, cough and breathlessness. Chest x-ray showed an increased infiltration of lung parenchyma. The patient was diagnosed as a case of paradoxical reaction to ATT and was managed successfully with steroids.
Focal cemento-osseous dysplasia of mandible
Authors: Cankaya Abdülkadir Burak , Erdem Mehmet Ali , Olgac Vakur , Firat Deniz Refia
Published: September 2012

Fibro-osseous lesions are disturbances in bone metabolism in which normal bone is replaced by a connective tissue matrix that then gradually develops into cemento-osseous tissue. Typically, the lesion is asymptomatic and is detected on routine radiographic examination. Radiologically, this lesion has three stages of maturation: pure radiolucent, radiopaque/mixed radiolucent, and radiopaque appearance. During these stages the lesion can be misdiagnosed. In this case report a 69-year- old patient with a a complaint of painless swelling of the left mandibular molar and premolar area is presented along with a review of the differential diagnoses considered in order to reach a final diagnosis of focal cemento-osseous dysplasia.
Spontaneous haemorrhage and rupture of third ventricular colloid cyst
Authors: Ogbodo Elisha , Kaliaperumal Chandrasekaran , Bermingham Niamh , O'Sullivan Michael
Published: September 2012

Acute bleeding within a colloid cyst of the third ventricle represents a rare event causing sudden increase in the cyst volume that may lead to acute hydrocephalus and rapid neurological deterioration. We report a case of spontaneous rupture of haemorrhagic third ventricular colloid cyst and its management. A 77-year-old ex-smoker presented with unsteady gait, incontinence and gradually worsening confusion over a 3-week period. Brain CT scan findings were highly suggestive of a third ventricular colloid cyst with intraventricular rupture. He underwent cyst excision and histopathology, which confirmed the radiological diagnosis with evidence of haemorrhage within the cyst. A ventriculo peritoneal shunt was performed for delayed hydrocephalus. Surgical management of these patients must include emergency ventriculostomy followed by prompt surgical removal of the haemorrhagic cyst.
Are complementary therapies and integrative care cost-effective? A systematic review of economic evaluations
Authors: Herman Patricia M , Poindexter Beth L , Witt Claudia M , Eisenberg David M
Published: September 2012

Objective

A comprehensive systematic review of economic evaluations of complementary and integrative medicine (CIM) to establish the value of these therapies to health reform efforts.

Data sources

PubMed, CINAHL, AMED, PsychInfo, Web of Science and EMBASE were searched from inception through 2010. In addition, bibliographies of found articles and reviews were searched, and key researchers were contacted.

Eligibility criteria for selecting studies

Studies of CIM were identified using criteria based on those of the Cochrane complementary and alternative medicine group. All studies of CIM reporting economic outcomes were included.

Study appraisal methods

All recent (and likely most cost-relevant) full economic evaluations published 2001–2010 were subjected to several measures of quality. Detailed results of higher-quality studies are reported.

Results

A total of 338 economic evaluations of CIM were identified, of which 204, covering a wide variety of CIM for different populations, were published 2001–2010. A total of 114 of these were full economic evaluations. And 90% of these articles covered studies of single CIM therapies and only one compared usual care to usual care plus access to multiple licensed CIM practitioners. Of the recent full evaluations, 31 (27%) met five study-quality criteria, and 22 of these also met the minimum criterion for study transferability (‘generalisability’). Of the 56 comparisons made in the higher-quality studies, 16 (29%) show a health improvement with cost savings for the CIM therapy versus usual care. Study quality of the cost-utility analyses (CUAs) of CIM was generally comparable to that seen in CUAs across all medicine according to several measures, and the quality of the cost-saving studies was slightly, but not significantly, lower than those showing cost increases (85% vs 88%, p=0.460).

Conclusions

This comprehensive review identified many CIM economic evaluations missed by previous reviews and emerging evidence of cost-effectiveness and possible cost savings in at least a few clinical populations. Recommendations are made for future studies.