bluuebunny/crossref_metadata_2025_split huggingface dataset:
Restoration of Mitochondrial NAD+ Levels Delays Stem Cell Senescence and Facilitates Reprogramming of Aged Somatic Cells
Authors: Son Myung Jin , Kwon Youjeong , Son Taekwon , Cho Yee Sook 
Published: July 2016

Abstract
The fundamental tenet that aging is irreversible has been challenged by the development of reprogramming technology that can restore molecular and cellular age by reversing the progression of aging. The use of cells from aged individuals as sources for reprogramming or transplantation creates a major barrier in stem cell therapy with respect to cell quality and quantity. Here, we investigated the molecular features underlying senescence and rejuvenation during aged cell reprogramming and identified novel factors that can overcome age-associated barriers. Enzymes, such as nicotinamide nucleotide transhydrogenase (NNT) and nicotinamide mononucleotide adenylyltransferase 3 (NMNAT3), that control mitochondrial NAD+ levels appear to be susceptible to aging. In aged cells, mitochondrial NAD+ levels decrease, accompanied by reduced SIRT3 activity; these changes severely impede cell fate transition. However, in cells collected from aged p16 knockout mice, which exhibit delayed cellular senescence, no changes in NNT or NMNAT3 expression were found. Importantly, restoring mitochondrial NAD+ levels by overexpressing NNT and NMNAT3 enhanced reprogramming efficiency of aged somatic cells and extended the lifespan of human mesenchymal stem cells by delaying replicative senescence. These results demonstrate that maintenance of mitochondrial NAD+ levels is critical for reversing the mechanisms of aging and ensuring that cells collected from aged individuals are of high quality.
Surgical Outcomes of Thoracic Myelopathy Secondary to Ossification of Ligamentum Flavum in a Regional Hospital: A Primitive Report and Literature Review
Authors: Eleanor Wen , Ki Ho Ka , Kin Cheung Ka 
Published: July 2016

Introduction Symptomatic thoracic stenosis is an uncommon disease in contrast to cervical and lumbar stenosis. It has been reported that ossification of ligamentum flavum (OLF) is the most common cause of thoracic myelopathy in our locality. Materials and Methods All patients with symptomatic thoracic spinal stenosis secondary to OLF who underwent operative treatment in our institution between January 1999 and December 2013 were retrospectively reviewed for demographic data, causes, complications and surgical outcomes. Results Twenty-six patients who underwent surgical treatment for symptomatic OLF were followed up for an average period of 71.3 months. All patients received decompression with concomitant instrumented fusion in 2 patients (7.7%). In our series, we had 2 cases (7.7%) of early post-operative neurological deterioration secondary to haematoma formation. Four cases (15.4%) were complicated with cerebrospinal fluid leakage. Operative outcome was reported in Frankel classification and modified Japanese Orthopedic Association (JOA) scale for thoracic myelopathy. After operation, 8 patients (30.8%) showed improvement in their Frankel grade, while 16 patients (61.5%) had no change and 2 patients (7.7%) reported deterioration. Mean JOA score showed significant improvement from 5.1 (range 2–8) to 6.9 post-operatively (range 2–11). Discussion and Conclusion OLF is the most common cause of thoracic myelopathy in our locality. Early accurate diagnosis and adequate surgical decompression are important for favourable outcomes despite operative difficulties and possible complications.
Translational Perspective on the Role of Testosterone in Sexual Function and Dysfunction
Authors: Podlasek Carol A. , Mulhall John , Davies Kelvin , Wingard Christopher J. , Hannan Johanna L. , Bivalacqua Trinity J. , Musicki Biljana , Khera Mohit , González-Cadavid Nestor F. , Burnett Arthur L. 
Published: July 2016

ABSTRACT

Introduction
The biological importance of testosterone is generally accepted by the medical community; however, controversy focuses on its relevance to sexual function and the sexual response, and our understanding of the extent of its role in this area is evolving.

Aim
To provide scientific evidence examining the role of testosterone at the cellular and molecular levels as it pertains to normal erectile physiology and the development of erectile dysfunction and to assist in guiding successful therapeutic interventions for androgen-dependent sexual dysfunction.

Methods
In this White Paper, the Basic Science Committee of the Sexual Medicine Society of North America assessed the current basic science literature examining the role of testosterone in sexual function and dysfunction.

Results
Testosterone plays an important role in sexual function through multiple processes: physiologic (stimulates activity of nitric oxide synthase), developmental (establishes and maintains the structural and functional integrity of the penis), neural (development, maintenance, function, and plasticity of the cavernous nerve and pelvic ganglia), therapeutically for dysfunctional regulation (beneficial effect on aging, diabetes, and prostatectomy), and phosphodiesterase type 5 inhibition (testosterone supplement to counteract phosphodiesterase type 5 inhibitor resistance).

Conclusion
Despite controversies concerning testosterone with regard to sexual function, basic science studies provide incontrovertible evidence for a significant role of testosterone in sexual function and suggest that properly administered testosterone therapy is potentially advantageous for treating male sexual dysfunction.
It's Not Just a Visit: Receiving Government Officials’ Visits and Firm Performance in China
Authors: Li Weiwen , Tsang Eric W. K. , Luo Danglun , Ying Qianwei 
Published: July 2016

ABSTRACTDrawing upon signaling theory, we propose that a specific form of non-market action, receiving government officials’ visits, reduces transaction costs between firms and their potential exchange partners and thus contributes to firms’ competitive advantage in China. We also contend that severity of information asymmetry and availability of alternative ways of reducing transaction costs moderate the relationship between receiving government officials’ visits and company financial performance in opposite directions. The former factor increases the ex ante value of receiving government officials’ visits and strengthens its positive impact on financial performance, while the latter factor decreases the ex post value of receiving government officials’ visits and reduces its positive impact. Our conceptual framework is supported by analyses that draw on a sample of listed manufacturing firms in China. Our study contributes to a more in-depth understanding of non-market actions in emerging economies, their contingencies, and their performance implications.
Asymptotic behavior of the node degrees in the ensemble average of adjacency matrix
Authors: HAYASHI YUKIO 
Published: July 2016

AbstractVarious important and useful quantities or measures that characterize the topological network structure are usually investigated for a network, then they are averaged over the samples. In this paper, we propose an explicit representation by the beforehand averaged adjacency matrix over samples of growing networks as a new general framework for investigating the characteristic quantities. It is applied to some network models, and shows a good approximation of degree distribution asymptotically. In particular, our approach will be applicable through the numerical calculations instead of intractable theoretical analyses, when the time-course of degree is a monotone increasing function like power law or logarithm.
Systems biology analyses of the dynamic host response to Toxoplasma gondii infection in a murine model
Authors: KHO MEE TECK , CHONG CHUN WIE , LIM ERIN SWEE HUA , ISMAIL NOR HADIANI , DRAPER LACHLAN OLIVER , YAM WAI KEAT , LIM PATRICIA KIM CHOOI , MAK JOON WAH , YAP IVAN K. S. 
Published: July 2016

SUMMARYToxoplasmosis affects a third of the global population and is of particular concern for immunologically compromised individuals. Toxoplasmosis induces host physiological events ranging from immunological to metabolic responses across multiple biological compartments. To understand the sequence of host responses during acute and chronicToxoplasma gondiiinfection, eight male BALB/c mice were infected with 2000T. gondiiME49 tachyzoites with a further eight uninfected mice used as controls. Plasma cytokines status, urinary metabolic profiling and fecal microbial profiles were characterized to monitor temporal variation related toT. gondiiinfection. The results showed elevated serum interferon-γ(IFN-γ), interleukin-12p40 and necrosis factor-αduring acute phase of infection with concomitant perturbation in host energy metabolism and host-gut microbiome co-metabolism of phenolics and a shift in microbial composition. However, the differences were less pronounced during the putative chronic phase of infection with elevated IFN-γ, differences in urinaryN-acetyls andO-acetyls of glycoproteins with no shift in gut microbial composition. Structural equation modelling on the current data showed host immune responses as the main driver for changes observed in urinary metabolites and gut microbial composition. Such an approach can be applied to other models of infectious diseases to aid understanding of host–pathogen interactions and potential biomarker discovery.
Overflow behavior in queues with many long-tailed inputs
Authors: Mandjes Michel , Borst Sem 
Published: July 2016

We consider a fluid queue fed by the superposition of n homogeneous on-off sources with generally distributed on and off periods. The buffer space B and link rate C are scaled by n, so that we get nb and nc, respectively. Then we let n grow large. In this regime, the overflow probability decays exponentially in the number of sources n. We specifically examine the scenario where b is also large. We obtain explicit asymptotics for the case where the on periods have a subexponential distribution, e.g., Pareto, Lognormal, or Weibull.The results show a sharp dichotomy in the qualitative behavior, depending on the shape of the function v(t) := - logP(A* > t) for large t, A* representing the residual on period. If v(.) is regularly varying of index 0 (e.g., Pareto, Lognormal), then, during the path to overflow, the input rate will only slightly exceed the link rate. Consequently, the buffer will fill ‘slowly’, and the typical time to overflow will be ‘more than linear’ in the buffer size. In contrast, if v(.) is regularly varying of index strictly between 0 and 1 (e.g., Weibull), then the input rate will significantly exceed the link rate, and the time to overflow is roughly proportional to the buffer size.In both cases there is a substantial fraction of the sources that remain in the on state during the entire path to overflow, while the others contribute at their mean rates. These observations lead to approximations for the overflow probability. The approximations may be extended to the case of heterogeneous sources. The results provide further insight into the so-called reduced-load approximation.
Part 1 — Introduction to the concept of axiomatic aerodynamic modelling
Authors: Hancock G. J. , Lam J. S. Y. 
Published: July 2016

SummaryThe aim of axiomatic aerodynamic modelling is introduced, namely to understand the validity of aerodynamic modelling in the context of aircraft dynamics with particular emphasis on understanding the relationship between full-scale flight behaviour as compared with that predicted from data based on wind tunnel tests.
A new boundary layer wind tunnel
Authors: Roach P. E. 
Published: July 2016

SummaryThe procedures employed for the design of a closed-circuit, boundary layer wind tunnel are described. The tunnel was designed for the generation of relatively large-scale, two-dimensional boundary layers with Reynolds numbers, pressure gradients and free-stream turbulence levels typical of the turbomachinery environment. The results of a series of tests to evaluate the tunnel performance are also described. The flow in the test section is shown to be highly uniform and steady, with very low (natural) free-stream turbulence intensities. Measured boundary layer mean and fluctuating velocity profiles were found to be in good agreement with classical correlations. Test-section free-stream turbulence intensities are presented for grid-generated turbulence: agreement with expectation is again found to be good. Immediate applications to the tunnel include friction drag reduction and boundary layer transition studies, with future possibilities including flow separation and other complex flows typical of those found in gas turbines.
A guide to classical flutter
Authors: Niblett L. T. 
Published: July 2016

SummaryFirst essentials of classical flutter are demonstrated by a comprehensive study of the behaviour of a lifting surface with two degrees of freedom under the action of airforces limited to those in phase with displacement. Structural coupling between the coordinates is eliminated by taking the normal modes to be the deflection coordinates, and this results in conditions for stability with particularly concise forms. It is shown that the flutter stability can be seen to be very much a matter of the relative amplitudes of heave and pitch in the normal modes.In-quadrature airforces are then introduced and it is shown that they have little effect when the flutter is severe. They are of more importance in the milder forms of flutter, the extreme of which are shown to be little different from instabilities in a single degree of freedom.
Computational analysis of unsteady supersonic cavity flows driven by thick shear layers
Authors: Zhang X. , Edwards J. A. 
Published: July 2016

AbstractSupersonic cavity flows driven by a thick shear layer at Mach 1·5 and 2·5 are studied by solving the two-dimensional unsteady compressible Navier-Stokes equations in terms of mass-averaged variables. The length to depth ratio of the rectangular cavity is three. The numerical scheme used is the finite-difference algorithm by Brailovskaya. A two-layer eddy-viscosity turbulence model is used. The results are compared with experimental data. The computations show the self-sustained oscillations at Mach 1·5 and 2·5. The continuous formation and downstream shedding of leading edge vortices is demonstrated. The oscillatory modes are correctly predicted. The first mode is attributed to a large unsteady trailing edge vortex moving in the transverse direction. Based on the analysis, it is considered that the oscillation in the length to depth ratio three cavity is a longitudinal one and is controlled by a fluid dynamic mechanism rather than a purely acoustic one.
The relation between losses and entry-flow conditions in short dump diffusers for combustors
Authors: Klein A. 
Published: July 2016

SummaryAn experimental correlation is presented between the losses and the inlet flow conditions in short dump diffusers for turbojet combustors. Cascades of compressor blades upstream of the diffuser were used to make the flow field at inlet similar to that in a real jet engine. The flow field was altered in two ways — by varying the distance between the cascades and the diffuser inlet plane and by changing the blade aspect ratio. The measurements show clearly that distortions in the radial direction affect the losses to a much larger extent than non-uniformities in the circumferential direction. In consequence, the performance can be correlated to a satisfactory degree of accuracy simply by using the radial blockage factor at inlet.
The boundary element method for analysing repair patches on cracked finite sheets
Authors: Young A. , Cartwright D. J. , Rooke D. P. 
Published: July 2016

SummaryThe boundary element method is combined with the method of compatible deformations to obtain stress intensity factors for a cracked sheet reinforced with a repair patch. The method is applied to the analysis of a circular patch over a central crack in a rectangular uniaxially stressed sheet. It is shown that the proximity of the edges of the sheet to the patch edge has a negligible effect on the stress intensity factor of a crack completely under the patch.
The air-injection method of fixing boundary-layer transition and investigating scale effects
Authors: Ashill P. R. , Fulker J. L. , Weeks D. J. 
Published: July 2016

SummaryThe paper describes the air-injection method of fixing transition in wind-tunnel tests on a two-dimensional aerofoil and a swept panel at high subsonic free-stream speeds. The method is shown to provide a repeatable level of disturbance which, for a given flow condition, may be generated without interrupting the test and which appears not to cause a significant excess drag. Examples are given illustrating the effectiveness of the technique in demonstrating scale-sensitive features of flows, and a correlation is presented which allows the minimum value of air-injection mass flow needed to fix transition to be estimated from a knowledge of the behaviour of natural laminar flow on the wing.
Flow visualisation on rolling models using minitufts
Authors: O'Leary C. O. , Drew W. 
Published: July 2016

SummaryMinitufts are increasingly used for flow visualisation on static wind tunnel models because they can be applied in larger numbers for increased detail and with less interference compared with conventional tufts. This Memorandum describes an extension of their use to continuously rotating models where the heavier conventional tufts are inadequate.Tests on two combat aircraft models in the 4 m x 2.7 m Low Speed Wind Tunnel are described. Measured variations of rolling moment are explained with the aid of the minituft photographs.
Stress analysis of a cylindrical shell with a variable wall thickness
Authors: Chehil D. S. , Jategaonkar R. , Dhaliwal R. S. 
Published: July 2016

SummaryWhile the bending analysis of cylindrical containers with wall thickness varying linearly has attracted much attention, it seems the general variation in wall thickness has not been considered. This is because of the difficulties which have been encountered due to the complex nature of the differential equations involved. In this paper, the container’s wall thickness is chosen to be of general variation and the differential equation is perturbed to give rise to a sequence of differential equations. It is shown that this sequence can be easily solved when the form of variation in wall thickness is specified. A complete solution is obtained in a particular case when the wall thickness varies linearly and the tank is subjected to hydrostatic pressure. For this particular case the numerical results are compared with the ones available in the literature which seem to be in good agreement.
The use of reliability techniques in civil aircraft structural airworthiness — a CAA view
Authors: James D. O. N. 
Published: July 2016

The safety of civil aircraft is regulated through a process of airworthiness certification and the application of operational regulations. The main elements of airworthiness are:(i) certification of the design,(ii) compliance with airworthiness requirements,(iii) maintenance and reaction to service problems -continued airworthiness.The airworthiness requirements are developed through a process of discussion and consultation with all interested parties. Whilst the result is largely a consensus view, the ultimate authority rests with the airworthiness authority. In recent years there have been increased efforts to reduce national differences with the aim of producing a single international code. At present there are two, with European and US international pressures tending to work against ‘improving’ requirements unless there is a clearly recognised need.
A summary of measurements of steady and oscillatory pressures on a rectangular wing
Authors: Mabey D. G. , Welsh B. L. , Pyne C. R. 
Published: July 2016

SummaryThis paper describes a series of steady and time-dependent pressure measurements on a half-model of a rectangular wing of aspect ratio 4. The wing was mounted on a half-body attached to a sidewall of the RAE 8 x 8 ft wind tunnel and the tests were made at Mach numbers of 0·20, 0·42, 0·70, 0·80 and 0·85 with fixed transition and a Reynolds number of about 2·5 x 106at the highest Mach number. The wing was oscillated about its mid-chord axis at four frequencies giving frequency parameters up to 1·15 at M = 0·20 and 0·25 at M = 0·85. The static angle of incidence was varied from –10° to + 10°.Selected mean and oscillatory measurements are offered as a challenge to computational fluid dynamicists for this simple three-dimensional configuration. Comparisons are made with calculations by means of subsonic linearised theory and recent transonic small perturbation methods. The measurements are of particular interest at transonic speeds, where both attached and incipient separated flows are considered.
Comparison of Euler and Navier-Stokes solutions for vortex flow over a delta wing
Authors: Rizzi A. , Müller B. 
Published: July 2016

SummaryA numerical method has been developed recently to solve the Navier-Stokes equations for laminar compressible flow around delta wings. A large-scale Navier-Stokes solution on a mesh of 129 × 49 × 65 points for transonic flow Mx = 0·85, α = 10° and Rex = 2·38 × 106 around a 65° swept delta wing with round leading edge is presented and compared with a correspondingly large-scale Euler solution. The viscous results reveal the presence of primary, secondary, and even tertiary vortices. The starting location of the primary vortex is seen to be quite different in the two solutions. In the viscous solution it starts at the wing apex, but in the Euler results it starts about one quarter chord downstream. The secondary reparations are also different, due to the up-lifting of the boundary layer in the viscous results, but to a cross-flow shock in the Euler computation. Comparison with experiment shows that the interaction between the primary and secondary vortices in the Navier-Stokes computation is obtained correctly and that these results are a more realistic simulation than the one given by the Euler equations.
Possible types of flow on lee-surface of delta wings at supersonic speeds
Authors: Seshadri S. N. , Narayan K. Y. 
Published: July 2016

SummaryExperiments were conducted to study the types of flow that occur on the lee surface of delta wings at supersonic speeds. Two sets of flat topped delta wings of different thickness (wedges with 10° and 25° normal angle respectively), each with leading edge sweep angles of 45°, 50°, 60° and 70°, were tested. The measurements, carried out at Mach numbers of 1·4, 1·6, 1·8, 2·0, 2·5 and 3·0, included oil flow visualisations (on both sets of wings) and static pressure distributions (on the thicker wing only). In addition, a 60° sweptback delta wing with a normal angle of 40° was also tested. The tests on this wing included both oil flow visualisations and static pressure measurements. From these and other existing measurements, the leeside flows have been classified into nine distinct types, namely (i) leading edge separated flow with secondary separation, (ii) leading edge separated flow with secondary and tertiary separation, (iii) leading edge separated flow with a shock wave beneath the primary vortex, (iv) leading edge separated flow with shock-induced secondary separation, (v) fully attached flow, (vi) flow attached at the leading edge with inboard shock-induced separation, (vii) mixed type of flow, (viii) flow with a leading edge separation bubble and (ix) leading edge separated flow with a shock wave lying on the lee surface in between the leading edge vortices. These types of flow have been displayed in a plane of Mach number and angle of attack normal to the leading edge. The experimental results indicate that increasing wing thickness has no qualitative effect on the types of flow observed but does shift the boundaries between some of the types of flow.