bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Elasto-Magneto-Electric (EME) Sensor for In-Service Cable Force Monitoring
Authors: Duan Yuan-Feng , Zhang Ru , Dong Chuan-Zhi , Luo Yao-Zhi , Or Siu Wing , Zhao Yang , Fan Ke-Qing
Published: January 2015

Stress/force monitoring of in-service steel structures is challenging but crucial to the evaluation of structural safety. A smart elasto-magneto-electric (EME) sensor was recently proposed by the authors for stress monitoring of steel components not only with the superiorities of the traditional elasto-magnetic (EM) sensors such as noncontact monitoring, actual-stress measurement, low cost, corrosion resistance and long expected service-life, but also with higher sensitivity, faster response and higher signal-to-noise ratio (SNR). In this paper, the application of the developed EME sensory system on the cable force monitoring of the Second Jiaojiang Bridge in China is presented. Full-scale experiment, factory calibration and in situ verification for engineering applications were successively carried out, which verify that the EME sensor is feasible and reliable to monitor the in-service cable force as a nondestructive testing (NDT) tool. Long-term on-line monitoring of the cable forces is in progress and the typical monitoring data over 7 months are presented and discussed. It is demonstrated that the proposed EME sensor is feasible for the in-service force monitoring of steel cables and that the EME sensory technology is suitable for developing the stable and reliable long-term monitoring system for steel structures.
Structural Health Monitoring System Developed for Dalian Stadium
Authors: Ren Liang , Yuan Chao-Lin , Li Hong-Nan , Yi Ting-Hua
Published: January 2015

The peripheral structure of Dalian stadium is a long-span spatial truss structure. To ensure the safety of the peripheral structure during construction and operation period, the permanent structure health monitoring system is implemented. This paper first introduces the structural features of the Dalian stadium, and then illustrates the permanent monitoring program from the aspects of the hardware, the monitoring scheme and the function. This developed monitoring system is utilized to monitor the stress of the truss, and the dynamic response of the structure. Large amounts of data are obtained through the health monitoring system, and thus the safe condition of the structure can be evaluated based on data analysis.
Study on Wind Characteristics of Runyang Suspension Bridge Based on Long-Term Monitored Data
Authors: Wang Hao , Guo Tong , Tao Tian-You , Li Ai-Qun
Published: January 2015

The slender and flexible characteristics make Runyang Suspension Bridge (RSB) sensitive to the wind actions. In order to obtain reliable statistical wind characteristics and monitor the wind environment at the bridge site, two anemometers are included in the structural health monitoring system (SHMS) to collect extensive wind data. In this paper, the recorded real-time wind data are analyzed in detail to acquire the wind rose diagram, mean wind speed and direction, turbulence intensity, turbulence integral scale, and power spectral density (PSD). Three strong wind events including Typhoon Matsa, Typhoon Khanun and Northern wind are comparatively analyzed to show the inhomogeneous wind characteristics. And the measured wind characteristics are compared with the recommended values in current specification of China. The analytical results show that the wind speed and wind direction at RSB site are greatly influenced by the subtropical monsoon climate and typhoon climate. And the traditional known rules concerning turbulence intensity are not proper for strong winds, while the rules can be validated by long-term monitored data. Meanwhile, the recommended values of turbulence integral scale by current specification are suitable for long-term monitored wind, but the adaptability to strong wind is still defective. In addition, the measured along-wind spectra match generally well with the commonly used PSDs of turbulence. However, more researches are still needed to refine current PSDs of turbulence to perfectly satisfy with the measured spectrum. The conclusions can provide references for the wind-resistant analysis of RSB and structures in similar areas.
Weakly principally quasi-Baer rings
Authors: Majidinya A. , Moussavi A.
Published: January 2015

We say a ring R with unity is weakly principally quasi-Baer or simply (weakly p.q.-Baer) if the right annihilator of a principal right ideal is right s-unital by right semicentral idempotents, which implies that R modulo the right annihilator of any principal right ideal is flat. It is proven that the weakly p.q.-Baer property is inherited by polynomial extensions and includes both left p.q.-Baer rings and right p.q.-Baer rings and is closed under direct products and Morita invariance. A ring R is weakly p.q.-Baer if and only if the upper triangular matrix ring Tn(R) is weakly p.q.-Baer. We extend a theorem of Kist for commutative Baer rings to weakly p.q.-Baer rings for which every prime ideal contains a unique minimal prime ideal without using topological arguments. It is also shown that there is an important subclass of weakly p.q.-Baer rings which have a nontrivial subdirect product representation.
On the construction of elliptic Chudnovsky-type algorithms for multiplication in large extensions of finite fields
Authors: Ballet Stéphane , Bonnecaze Alexis , Tukumuli Mila
Published: January 2015

We indicate a strategy in order to construct bilinear multiplication algorithms of type Chudnovsky in large extensions of any finite field. In particular, using the symmetric version of the generalization of Randriambololona specialized on the elliptic curves, we show that it is possible to construct such algorithms with low bilinear complexity. More precisely, if we only consider the Chudnovsky-type algorithms of type symmetric elliptic, we show that the symmetric bilinear complexity of these algorithms is in [Formula: see text] where n corresponds to the extension degree, and [Formula: see text] is the iterated logarithm. Moreover, we show that the construction of such algorithms can be done in time polynomial in n. Finally, applying this method we present the effective construction, step by step, of such an algorithm of multiplication in the finite field 𝔽357.
On the generalized norm of a finite group
Authors: Gong Lü , Zhao Libo , Guo Xiuyun
Published: January 2015

The main aim of this paper is to investigate two characteristic subgroups ω𝒜(G) and θ𝒜(G) of a finite group G, which are defined as the intersections of the normalizers of derived subgroups of subnormal and non-subnormal subgroups of G respectively. Our main theory improve and extend some earlier results.
On matching property for groups and field extensions
Authors: Aliabadi Mohsen , Hadian Majid , Jafari Amir
Published: January 2015

In this paper we prove a sufficient condition for the existence of matchings in arbitrary groups and its linear analogue, which lead to some generalizations of the existing results in the theory of matchings in groups and central extensions of division rings. We introduce the notion of relative matchings between arrays of elements in groups and use this notion to study the behavior of matchable sets under group homomorphisms. We also present infinite families of prime numbers p such that ℤ/pℤ does not have the acyclic matching property. Finally, we introduce the linear version of acyclic matching property and show that purely transcendental field extensions satisfy this property.
Torsion units in the integral group ring of PSL(3, 4)
Authors: Gildea Joe , Tylyshchak Alexander
Published: January 2015

We investigate the Zassenhaus Conjecture for the integral group ring of the simple group PSL(3, 4).
A visit to maximal non-ACCP subrings
Authors: Jarboui Noômen , Toumi Manar El Islam
Published: January 2015

In this paper, we characterize maximal non-ACCP subrings R of a domain S in case (R, S) is a residually algebraic pair and R is semilocal. In this paper, we also consider a K-algebra S, a nonzero proper ideal I of S and a subring D of the field K and we determine necessary and sufficient conditions in order that D + I is a maximal non-ACCP subring of S. This gives an example of a maximal non-ACCP subring R of a domain S such that (R, S) is a normal pair and R is not semilocal.
World Search Engine IQ Test Based on the Internet IQ Evaluation Algorithms
Authors: Liu Feng , Shi Yong , Wang Bo
Published: January 2015

With increasing concern about Internet intelligence, this paper proposes concepts of the Internet and Internet subsystem IQs over search engines. Based on human IQ calculations, the paper first establishes a 2014 Internet Intelligence Scale and designs an intelligence test bank regarding search engines. Then, an intelligence test using such test bank is carried out on 50 typical search engines from 25 countries and regions across the world. Meanwhile, another intelligence test is also conducted in the human age groups of 6, 12 and 18 years using the same test bank and rules. Next, the absolute IQ and the relative IQ of the 53 test subjects are calculated in accordance with the test results. Finally, the data mining method is applied to find out the features of search engines reflected in the Internet intelligence test and the intelligence difference between search engines and human beings.
Payment Systems in New Electronic Environments: Consumer Behavior in Payment Systems via SMS
Authors: Francisco Liebana-Cabanillas , Francisco Muñoz-Leiva , Juan Sanchez-Fernandez
Published: January 2015

The main goal of our research is to analyze users' acceptance of mobile payment systems, considering the population's widespread use of mobile devices. In order to explain acceptance, we have added trust and perceived risk to the traditional variables. To this end, we have carried out a study through an online survey to a national panel of Internet users. The results of this survey check the implications considered on the basis of the Technological Acceptance Model, the Theory of Reasoned Action and the trust building principles for a given system. The conclusions and implications for management provide alternatives for companies to promote this new business by means of the new technical developments.
Theoretical exploration to the cation effect on the second-order nonlinear optical properties of Strandberg-type polyoxometalates
Authors: Zhang Ting , Guan Wei , Wen Shizheng , Ma Tengying , Yan Likai , Su Zhongmin
Published: January 2015

The combination of cations with octahedral coordinated d0 transition metal ions has been proved to be an effective way for designing new polar materials. So we investigate the second-order nonlinear optical (NLO) properties of Strandberg-type polyoxometalates (POMs) with alkali metal cations M 6 Mo 5 X 2 O 23 ( M = K +, Rb +, Cs +; X = P , As ) and M 4 M o5 X 2 O 21 ( M = K +, Rb +, Cs +; X = S , Se , Te ) by density functional theory (DFT) method. The calculated results show that this kind of Strandberg-type POMs possesses remarkably large molecular second-order NLO polarizability, especially for the Cs 6 Mo 5 P 2 O 23 (system Ic), which has a computed β0 value of 12526 a.u. and might be an excellent second-order NLO material. Moreover, the cations have important impact on the second-order NLO polarizabilities. Therefore, a careful choice of appropriate cations may allow the control of the second-order NLO response on these Strandberg-type POMs, which may provide a new route to design efficient NLO materials.
Experimental violation of a d-dimensional Bell inequality using energy-time entangled photons
Authors: Schwarz Sacha , Bessire Bänz , Stefanov André
Published: January 2015

We experimentally study the violation of the CGLMP inequality for entangled 2-qubit and 2-qutrit states with different degrees of entanglement using numerically optimized measurement settings. The qudits are encoded and manipulated in the frequency spectrum of broadband energy-time entangled photons by taking into account a spatial light modulator (SLM). The latter allows to discretize the spectrum into bins. By controlling each frequency bin individually, the generation of maximally and non-maximally entangled qutrits is verified through quantum state tomography (QST).
Design of diethynyl porphyrin derivatives with high near infrared fluorescence quantum yields
Authors: Susumu Kimihiro , Therien Michael J.
Published: January 2015

A design strategy for (porphinato)zinc-based fluorophores that possess large near infrared fluorescence quantum yields is described. These fluorophores are based on a (5,15-diethynylporphinato)zinc(II) framework and feature symmetric donor or acceptor units appended at the meso-ethynyl positions via benzo[c][1,2,5]thiadiazole moieties. These (5,15-bis(benzo[c][1′,2′,5′]thiadiazol-4′-ylethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (4), (5,15-bis[4′-(N,N-dihexylamino) benzo[c][1′,2′,5′]thiadiazol-7′-ylethynyl]-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (5), (5,15-bis([7′-(4″-n-dodecyloxyphenylethynyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (6), (5,15-bis([7′-([7″-(4″ ′-n-dodecyloxyphenyl)benzo[c][1″,2″,5″]thiadiazol-4″-yl]ethynyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (7), 5,15-bis ([7′-(4″-N,N-dihexylaminophenylethynyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (8), and (5,15-bis([7′-(4″-N,N-dihexylaminophenylethenyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (9) chromophores possess red-shifted absorption and emission bands that range between 650 and 750 nm that bear distinct similarities to those of the chlorophylls and structurally related molecules. Interestingly, the measured radiative decay rate constants for these emitters track with the integrated oscillator strengths of their respective x-polarized Q-band absorptions, and thus define an unusual family of high quantum yield near infrared fluorophores in which emission intensity is governed by a simple Strickler–Berg dependence.
Study on Free Convection Heat Transfer in a Finned Tube Array
Authors: Katsuki Ryoji , Shioyama Tsutomu , Iwaki Chikako , Yanazawa Tadamichi
Published: January 2015

We have been developing a free convection air cooled heat exchanger without power supply to improve economic efficiency and mechanical reliability. However, this heat exchanger requires a larger installation area than the forced draft type air cooled heat exchanger since a large heating surface is needed to compensate for the small heat transfer by natural convection. Therefore, we have been investigating a heat exchanger consisting of an array of finned tubes and chimney to increase the heat transfer coefficient. Since the heat transfer characteristics of finned tube arrays have not been clarified, we conducted experiments with a finned tube array to determine the relation between the configuration of finned tubes and the heat transfer coefficient of a tube array. The results showed that the average heat transfer coefficient increased with pitch in the vertical direction, and became constant when the pitch was over five times the fin diameter. The average heat transfer coefficient was about 1.4 times higher than that of a single finned tube in free space. The ratio of the average heat transfer coefficient of the finned tube array with chimney to that of a single finned tube was found to be independent of the difference in temperature between the tube surface and air.
Analysis of the Condensate Carryover Phenomenon on Fin and Tube Evaporators
Authors: Navarro-Peris Emilio , Corberan Jose Miguel , Gonzalvez Jose , Zamora Miguel
Published: January 2015

Possible carryover of the condensate from the surface of the evaporator has always been a problem that in practice has been solved by limiting the air velocity. However, the need for more compact solutions and especially for the reduction of the frontal area in many applications requires the increase of the air velocity and therefore new solutions to overcome this problem must be developed. In this contribution, the authors develop an analytical model to estimate the evolution of the condensing drops over the fin surface of a heat exchanger as a function of the fin surface properties and air velocity. This model allows the estimation of the drop size when it starts to move and its trajectory and evolution along the fin. The possibility of drops forming water bridges in between the fins is also analyzed with estimation of the minimum fin separation to avoid its formation depending on the air velocity and the wettability of the fin surface. Finally, the results of an experimental campaign performed with two fin and tube coils of exactly same dimensions and geometry but with different fin materials: one with the standard aluminum fin and the other one with a specially outer hydrophilic layer, are presented, showing that this kind of coating avoids the condensate carryover with no appreciable penalty on the heat transfer performance.
Mapping landslides at different scales
Authors: Griffiths James S. , Mather Anne E. , Stokes Martin
Published: January 2015

Landslides can be mapped for purely academic reasons to understand their nature and properties, or for engineering purposes because they constitute a hazard to an existing human activity or a proposed development. The scale of the mapping to be carried out will be influenced by the requirements of the investigation. For engineering investigations large-scale mapping (>1:10000) is generally the most appropriate whereas for academic studies smaller-scale mapping can be just as valuable as it can reveal much about the role landsliding has in overall landscape development. In this paper three examples of mapping landslides at different scales are presented and the implications for the mapping procedures employed are explored. These examples are: (1) large-scale mapping of an active landslide affecting a road and mobile home site on the SW coast of the Isle of Wight, UK; (2) medium-scale mapping of landslides in the proximity of a river capture site in SE Spain; (3) small-scale mapping of large coastal landslides in northern Chile and the implications for mass sediment transfer along an active subduction margin. All three mapping programmes had a clear focus and intent but the method employed varied with the purpose of the investigation and the scale of the mapping that was carried out. It was concluded that it is important for any landslide mapping programme to have clearly identified objectives from the outset if time, and money, is not be wasted. However, even in site-specific investigations it is imperative for landslides to be seen in the wider context of their geomorphological situation with their role in landscape development assessed so as to understand the likelihood and potential magnitude of any hazards.
Volcanic volumes associated with the Kenya Rift: recognition and correction of preservation biases
Authors: Guth A. L.
Published: January 2015

New eruptive volume estimates have been calculated for the Kenyan segment of the East African Rift. Since the initial publications of volume estimates for the Kenyan Rift, numerous age dates have been obtained for the region allowing for temporal analysis of eruptive volumes. Additionally, more recent available datasets allow for the independent testing of map-derived volumes. Newly calculated volumes from available seismic data indicate a total volume of
c.
310 000 km
3
, which is significantly more than map-derived volumes found here or published previously. It is suggested that the map-based estimates are likely affected by biases against recognizing small volume events in the older record. Such events have been, however, the main driver of erupted volume over the last 5 Ma. A simple ratio-adjustment technique was developed to counter these biases and results in convergence of the volume estimates from the two independent datasets examined.

Supplementary material:

Volume calculations and classifications are available at
http://www.geolsoc.org.uk/SUP18800
.
Myoferlin depletion elevates focal adhesion kinase and paxillin phosphorylation and enhances cell-matrix adhesion in breast cancer cells
Authors: Blackstone B. N. , Li R. , Ackerman W. E. , Ghadiali S. N. , Powell H. M. , Kniss D. A.
Published: January 2015

Breast cancer is the second leading cause of malignant death among women. A crucial feature of metastatic cancers is their propensity to lose adhesion to the underlying basement membrane as they transition to a motile phenotype and invade surrounding tissue. Attachment to the extracellular matrix is mediated by a complex of adhesion proteins, including integrins, signaling molecules, actin and actin-binding proteins, and scaffolding proteins. Focal adhesion kinase (FAK) is pivotal for the organization of focal contacts and maturation into focal adhesions, and disruption of this process is a hallmark of early cancer invasive potential. Our recent work has revealed that myoferlin (MYOF) mediates breast tumor cell motility and invasive phenotype. In this study we demonstrate that noninvasive breast cancer cell lines exhibit increased cell-substrate adhesion and that silencing of MYOF using RNAi in the highly invasive human breast cancer cell line MDA-MB-231 also enhances cell-substrate adhesion. In addition, we detected elevated tyrosine phosphorylation of FAK (FAKY397) and paxillin (PAXY118), markers of focal adhesion protein activation. Morphometric analysis of PAX expression revealed that RNAi-mediated depletion of MYOF resulted in larger, more elongated focal adhesions, in contrast to cells transduced with a control virus (MDA-231LVC cells), which exhibited smaller focal contacts. Finally, MYOF silencing in MDA-MB-231 cells exhibited a more elaborate ventral cytoskeletal structure near focal adhesions, typified by pronounced actin stress fibers. These data support the hypothesis that MYOF regulates cell adhesions and cell-substrate adhesion strength and may account for the high degree of motility in invasive breast cancer cells.
Voluntary suppression of hyperthermia-induced hyperventilation mitigates the reduction in cerebral blood flow velocity during exercise in the heat
Authors: Tsuji Bun , Honda Yasushi , Ikebe Yusuke , Fujii Naoto , Kondo Narihiko , Nishiyasu Takeshi
Published: January 2015

Hyperthermia during prolonged exercise leads to hyperventilation, which can reduce arterial CO2 pressure (PaCO2) and, in turn, cerebral blood flow (CBF) and thermoregulatory response. We investigated 1) whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and 2) the effects of voluntary breathing control on PaCO2, CBF, sweating, and skin blood flow. Twelve male subjects performed two exercise trials at 50% of peak oxygen uptake in the heat (37°C, 50% relative humidity) for up to 60 min. Throughout the exercise, subjects breathed normally (normal-breathing trial) or they tried to control their minute ventilation (respiratory frequency was timed with a metronome, and target tidal volumes were displayed on a monitor) to the level reached after 5 min of exercise (controlled-breathing trial). Plotting ventilatory and cerebrovascular responses against esophageal temperature (Tes) showed that minute ventilation increased linearly with rising Tes during normal breathing, whereas controlled breathing attenuated the increased ventilation (increase in minute ventilation from the onset of controlled breathing: 7.4 vs. 1.6 l/min at +1.1°C Tes; P < 0.001). Normal breathing led to decreases in estimated PaCO2 and middle cerebral artery blood flow velocity (MCAV) with rising Tes, but controlled breathing attenuated those reductions (estimated PaCO2 −3.4 vs. −0.8 mmHg; MCAV −10.4 vs. −3.9 cm/s at +1.1°C Tes; P = 0.002 and 0.011, respectively). Controlled breathing had no significant effect on chest sweating or forearm vascular conductance ( P = 0.67 and 0.91, respectively). Our results indicate that humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise, and this suppression mitigates changes in PaCO2 and CBF.
A hypoxic episode during cardiogenesis downregulates the adenosinergic system and alters the myocardial anoxic tolerance
Authors: Robin Elodie , Marcillac Fabrice , Raddatz Eric
Published: January 2015

To what extent hypoxia alters the adenosine (ADO) system and impacts on cardiac function during embryogenesis is not known. Ectonucleoside triphosphate diphosphohydrolase (CD39), ecto-5′-nucleotidase (CD73), adenosine kinase (AdK), adenosine deaminase (ADA), equilibrative (ENT1,3,4), and concentrative (CNT3) transporters and ADO receptors A1, A2A, A2B, and A3 constitute the adenosinergic system. During the first 4 days of development chick embryos were exposed in ovo to normoxia followed or not followed by 6 h hypoxia. ADO and glycogen content and mRNA expression of the genes were determined in the atria, ventricle, and outflow tract of the normoxic (N) and hypoxic (H) hearts. Electrocardiogram and ventricular shortening of the N and H hearts were recorded ex vivo throughout anoxia/reoxygenation ± ADO. Under basal conditions, CD39, CD73, ADK, ADA, ENT1,3,4, CNT3, and ADO receptors were differentially expressed in the atria, ventricle, and outflow tract. In H hearts ADO level doubled, glycogen decreased, and mRNA expression of all the investigated genes was downregulated by hypoxia, except for A2A and A3 receptors. The most rapid and marked downregulation was found for ADA in atria. H hearts were arrhythmic and more vulnerable to anoxia-reoxygenation than N hearts. Despite downregulation of the genes, exposure of isolated hearts to ADO 1) preserved glycogen through activation of A1 receptor and Akt-GSK3β-GS pathway, 2) prolonged activity and improved conduction under anoxia, and 3) restored QT interval in H hearts. Thus hypoxia-induced downregulation of the adenosinergic system can be regarded as a coping response, limiting the detrimental accumulation of ADO without interfering with ADO signaling.
ANP-induced signaling cascade and its implications in renal pathophysiology
Authors: Theilig Franziska , Wu Qingyu
Published: January 2015

The balance between vasoconstrictor/sodium-retaining and vasodilator/natriuretic systems is essential for maintaining body fluid and electrolyte homeostasis. Natriuretic peptides, such as atrial natriuretic peptide (ANP), belong to the vasodilator/natriuretic system. ANP is produced by the conversion of pro-ANP into ANP, which is achieved by a proteolytical cleavage executed by corin. In the kidney, ANP binds to the natriuretic peptide receptor-A (NPR-A) and enhances its guanylyl cyclase activity, thereby increasing intracellular cyclic guanosine monophosphate production to promote natriuretic and renoprotective responses. In the glomerulus, ANP increases glomerular permeability and filtration rate and antagonizes the deleterious effects of the renin-angiotensin-aldosterone system activation. Along the nephron, natriuretic and diuretic actions of ANP are mediated by inhibiting the basolaterally expressed Na+-K+-ATPase, reducing apical sodium, potassium, and protein organic cation transporter in the proximal tubule, and decreasing Na+-K+-2Cl−cotransporter activity and renal concentration efficiency in the thick ascending limb. In the medullary collecting duct, ANP reduces sodium reabsorption by inhibiting the cyclic nucleotide-gated cation channels, the epithelial sodium channel, and the heteromeric channel transient receptor potential-vanilloid 4 and -polycystin 2 and diminishes vasopressin-induced water reabsorption. Long-term ANP treatment may lead to NPR-A desensitization and ANP resistance, resulting in augmented sodium and water reabsorption. In mice, corin deficiency impairs sodium excretion and causes salt-sensitive hypertension. Characteristics of ANP resistance and corin deficiency are also encountered in patients with edema-associated diseases, highlighting the importance of ANP signaling in salt-water balance and renal pathophysiology.
Vasopressin-regulated miRNAs and AQP2-targeting miRNAs in kidney collecting duct cells
Authors: Kim Jae-Eun , Jung Hyun Jun , Lee Yu-Jung , Kwon Tae-Hwan
Published: January 2015

Mature microRNA (miRNA) acts as an important posttranscriptional regulator. We aimed to profile vasopressin-responsive miRNAs in kidney inner medullary collecting duct cells and to identify aquaporin-2 (AQP2)-targeting miRNAs. Microarray chip assay was carried out in inner medullary collecting duct tubule suspensions from rat kidneys in the absence or presence of desmopressin (dDAVP) stimulation (10−9 M, 2 h). The results demonstrated 19 miRNAs, including both precursor and mature miRNAs, as potential candidates that showed significant changes in expression after dDAVP stimulation ( P < 0.05). Nine mature miRNAs exhibiting >1.3-fold changes in expression on the microarray (miR-127, miR-1, miR-873, miR-16, miR-206, miR-678, miR-496, miR-298, and miR-463) were further examined by quantitative real-time PCR, and target genes of the selected miRNAs were predicted. Next, to identify AQP2-targeting miRNAs, in silico analysis was performed. Four miRNAs (miR-32, miR-137, miR-216a, and miR-216b) target the 3′-untranslated region of rat AQP2 mRNA. Target seed regions of miR-32 and miR-137 were also conserved in the 3′-untranslated region of mouse AQP2 mRNA. Quantitative real-time PCR and immunoblot analysis demonstrated that dDAVP-induced AQP2 expression was significantly attenuated in mpkCCDc14 cells when cells were transfected with miRNA mimics of miR-32 or miR-137. Moreover, luciferase reporter assay demonstrated a significant decrease of AQP2 translation in mpkCCDc14 cells transfected with miRNA mimics of miR-32 or miR-137. The present study provides novel insights into the regulation of AQP2 by RNA interference; however, vasopressin-regulated miRNAs did not include miR-32 or miR-137, indicating that the interaction of miRNAs with the AQP2 regulatory pathway requires further analysis.
Signaling Rho-kinase mediates inflammation and apoptosis in T cells and renal tubules in cisplatin nephrotoxicity
Authors: Nozaki Yuji , Kinoshita Koji , Hino Shoichi , Yano Tomohiro , Niki Kaoru , Hirooka Yasuaki , Kishimoto Kazuya , Funauchi Masanori , Matsumura Itaru
Published: January 2015

Nephrotoxicity is a frequent complication of cisplatin-induced chemotherapy, in which T cells are known to promote acute kidney injury (AKI). Apoptosis and necrosis of tubules and inflammatory events also contribute to the nephrotoxicity. A delineation of the mechanisms that underlie the inappropriate renal and tubular inflammation can thus provide important insights into potential therapies for cisplatin-induced AKI. Rho-kinases are known to act as molecular switches controlling several critical cellular functions, including cell migration, cytokine production, and apoptosis. Here, we show that the Rho-kinase inhibitor fasudil attenuated cisplatin nephrotoxicity, resulting in less histological damage, improved renal function, and the infiltration of fewer leukocytes into the kidney. Renal nuclear factor-κB activation and apoptosis were reduced, and the expressions of proinflammatory renal cytokine and chemokine mRNA were decreased. Urinary and renal kidney injury molecule-1 (Kim-1) expression was also reduced, a finding that is consistent with diminished kidney injury. In the current study, we also showed that fasudil could be protective of the impaired tubules. In vitro, fasudil reduced the apoptosis (annexin-V+PI cells) and cytokine production (tumor necrosis factor+ cells) in T cells and the apoptosis (annexin-V+PI cells) and tubular damage (Kim-1+ cells) in proximal tubular cells by flow cytometric analysis. As Rho-kinase plays an important role in promoting cisplatin nephrotoxicity, inhibiting Rho-kinase may be a therapeutic strategy for preventing cisplatin-induced AKI.
Extracellular pH affects phosphorylation and intracellular trafficking of AQP2 in inner medullary collecting duct cells
Authors: Choi Hyo-Jung , Jung Hyun Jun , Kwon Tae-Hwan
Published: January 2015

Kidney collecting duct cells are continuously exposed to the changes of extracellular pH (pHe). We aimed to study the effects of altered pHeon desmopressin (dDAVP)-induced phosphorylation (Ser256, Ser261, Ser264, and Ser269) and apical targeting of aquaporin-2 (AQP2) in rat kidney inner medullary collecting duct (IMCD) cells. When freshly prepared IMCD tubule suspensions exposed to HEPES buffer with pH 5.4, 6.4, 7.4, or 8.4 for 1 h were stimulated with dDAVP (10−10M, 3 min), AQP2 phosphorylation at Ser256, Ser264, and Ser269was significantly attenuated under acidic conditions. Next, IMCD cells primary cultured in transwell chambers were exposed to a transepithelial pH gradient for 1 h (apical pH 6.4, 7.4, or 8.4 vs. basolateral pH 7.4 and vice versa). Immunocytochemistry and cell surface biotinylation assay revealed that exposure to either apical pH 6.4 or basolateral pH 6.4 for 1 h was associated with decreased dDAVP (10−9M, 15 min, basolateral)-induced apical targeting of AQP2 and surface expression of AQP2. Fluorescence resonance energy transfer analysis revealed that the dDAVP (10−9M)-induced increase of PKA activity was significantly attenuated when LLC-PK1 cells were exposed to pHe6.4 compared with pHe7.4 and 8.4. In contrast, forskolin (10−7M)-induced PKA activation and dDAVP (10−9M)-induced increases of intracellular Ca2+were not affected. Taken together, dDAVP-induced phosphorylation and apical targeting of AQP2 are attenuated in IMCD cells under acidic pHe, likely via an inhibition of vasopressin V2 receptor-G protein-cAMP-PKA actions.
MAD2B contributes to podocyte injury of diabetic nephropathy via inducing cyclin B1 and Skp2 accumulation
Authors: Su Hua , Wan Qiang , Tian Xiu-Juan , He Fang-Fang , Gao Pan , Tang Hui , Ye Chen , Fan Di , Chen Shan , Wang Yu-Mei , Meng Xian-Fang , Zhang Chun
Published: January 2015

It is well documented that mitotic arrest deficiency (MAD)2B can inhibit the anaphase-promoting complex/cyclosome (APC/C) via cadherin (Cdh)1 and, consequently, can destroy the effective mitotic spindle checkpoint control. Podocytes have been observed to rapidly detach and die when being forced to bypass cell cycle checkpoints. However, the role of MAD2B, a cell cycle regulator, in podocyte impairment of diabetic nephropathy (DN) is unclear. In the present study, we investigated the significance of MAD2B in the pathogenesis of DN in patients, an animal model, and in vitro podocyte cultures. By Western blot and immunohistochemistry analyses, we found that MAD2B was evidently upregulated under high glucose milieu in vivo and in vitro, whereas Cdh1 was inhibited with high glucose exposure. Overexpression of MAD2B in podocytes by plasmid DNA transfection suppressed expression of Cdh1 and triggered the accumulation of cyclin B1 and S phase kinase-associated protein (Skp)2, two key molecules involving in cell cycle regulation, and the subsequent podocyte insult. In contrast, MAD2B deletion alleviated the high glucose-induced reduction of Cdh1 as well as the elevation of cyclin B1 and Skp2, which rescued the podocyte from damage. Taken together, our data demonstrate that MAD2B may play an important role in high glucose-mediated podocyte injury of DN via modulation of Cdh1, cyclin B1, and Skp2 expression.
Antithrombin nanoparticles improve kidney reperfusion and protect kidney function after ischemia-reperfusion injury
Authors: Chen Junjie , Vemuri Chandu , Palekar Rohun U. , Gaut Joseph P. , Goette Matthew , Hu Lingzhi , Cui Grace , Zhang Huiying , Wickline Samuel A.
Published: January 2015

In the extension phase of acute kidney injury, microvascular thrombosis, inflammation, vasoconstriction, and vascular endothelial cell dysfunction promote progressive damage to renal parenchyma after reperfusion. In this study, we hypothesized that direct targeting and pharmaceutical knockdown of activated thrombin at the sites of injury with a selective nanoparticle (NP)-based thrombin inhibitor, PPACK (phenylalanine-proline-arginine-chloromethylketone), would improve kidney reperfusion and protect renal function after transient warm ischemia in rodent models. Saline- or plain NP-treated animals were employed as controls. In vivo 19F magnetic resonance imaging revealed that kidney nonreperfusion was evident within 3 h after global kidney reperfusion at 34 ± 13% area in the saline group and 43 ± 12% area in the plain NP group and substantially reduced to 17 ± 4% (∼50% decrease, P < 0.05) in the PPACK NP pretreatment group. PPACK NP pretreatment prevented an increase in serum creatinine concentration within 24 h after ischemia-reperfusion, reflecting preserved renal function. Histologic analysis illustrated substantially reduced intrarenal thrombin accumulation within 24 h after reperfusion for PPACK NP-treated kidneys (0.11% ± 0.06%) compared with saline-treated kidneys (0.58 ± 0.37%). These results suggest a direct role for thrombin in the pathophysiology of AKI and a nanomedicine-based preventative strategy for improving kidney reperfusion after transient warm ischemia.
Impacts of nitric oxide and superoxide on renal medullary oxygen transport and urine concentration
Authors: Fry Brendan C. , Edwards Aurélie , Layton Anita T.
Published: January 2015

The goal of this study was to investigate the reciprocal interactions among oxygen (O2), nitric oxide (NO), and superoxide (O2−) and their effects on medullary oxygenation and urinary output. To accomplish that goal, we developed a detailed mathematical model of solute transport in the renal medulla of the rat kidney. The model represents the radial organization of the renal tubules and vessels, which centers around the vascular bundles in the outer medulla and around clusters of collecting ducts in the inner medulla. Model simulations yield significant radial gradients in interstitial fluid oxygen tension (Po2) and NO and O2− concentration in the OM and upper IM. In the deep inner medulla, interstitial fluid concentrations become much more homogeneous, as the radial organization of tubules and vessels is not distinguishable. The model further predicts that due to the nonlinear interactions among O2, NO, and O2−, the effects of NO and O2− on sodium transport, osmolality, and medullary oxygenation cannot be gleaned by considering each solute's effect in isolation. An additional simulation suggests that a sufficiently large reduction in tubular transport efficiency may be the key contributing factor, more so than oxidative stress alone, to hypertension-induced medullary hypoxia. Moreover, model predictions suggest that urine Po2 could serve as a biomarker for medullary hypoxia and a predictor of the risk for hospital-acquired acute kidney injury.
Regulation of glomerulotubular balance. III. Implication of cytosolic calcium in flow-dependent proximal tubule transport
Authors: Du Zhaopeng , Weinbaum Sheldon , Weinstein Alan M. , Wang Tong
Published: January 2015

In the proximal tubule, axial flow (drag on brush-border microvilli) stimulates Na+ and HCO3− reabsorption by modulating both Na/H exchanger 3 (NHE3) and H-ATPase activity, a process critical to glomerulotubular balance. We have also demonstrated that blocking the angiotensin II receptor decreases baseline transport, but preserves the flow effect; dopamine leaves baseline fluxes intact, but abrogates the flow effect. In the current work, we provide evidence implicating cytosolic calcium in flow-dependent transport. Mouse proximal tubules were microperfused in vitro at perfusion rates of 5 and 20 nl/min, and reabsorption of fluid ( Jv) and HCO3− ( JHCO3) were measured. We examined the effect of high luminal Ca2+ (5 mM), 0 mM Ca2+, the Ca2+ chelator BAPTA-AM, the inositol 1,4,5-trisphosphate (IP3) receptor antagonist 2-aminoethoxydiphenyl borate (2-APB), and the Ca-ATPase inhibitor thapsigargin. In control tubules, increasing perfusion rate from 5 to 20 nl/min increased Jv by 62% and JHCO3 by 104%. With respect to Na+ reabsorption, high luminal Ca2+ decreased transport at low flow, but preserved the flow-induced increase; low luminal Ca2+ had little impact; both BAPTA and 2-APB had no effect on baseline flux, but abrogated the flow effect; thapsigargin decreased baseline flow, leaving the flow effect intact. With respect to HCO3− reabsorption, high luminal Ca2+ decreased transport at low flow and mildly diminished the flow-induced increase; low luminal Ca2+ had little impact; both BAPTA and 2-APB had no effect on baseline flux, but abrogated the flow effect. These data implicate IP3 receptor-mediated intracellular Ca2+ signaling as a critical step in transduction of microvillous drag to modulate Na+ and HCO3− transport.
Exercise training reverses aging-induced impairment of myogenic constriction in skeletal muscle arterioles
Authors: Ghosh Payal , Mora Solis Fredy R. , Dominguez James M. , Spier Scott A. , Donato Anthony J. , Delp Michael D. , Muller-Delp Judy M.
Published: January 2015

To investigate whether exercise training can reverse age-related impairment of myogenic vasoconstriction in skeletal muscle arterioles, young (4 mo) and old (22 mo) male Fischer 344 rats were randomly assigned to either sedentary or exercise-trained groups. The roles of the endothelium and Kv1 channels in age- and exercise training-induced adaptations of myogenic responses were assessed through evaluation of pressure-induced constriction in endothelium-intact and denuded soleus muscle arterioles in the presence and absence of the Kv1 channel blocker, correolide. Exercise training enhanced myogenic constriction in arterioles from both old and young rats. In arterioles from old rats, exercise training restored myogenic constriction to a level similar to that of arterioles from young sedentary rats. Removal of the endothelium did not alter myogenic constriction of arterioles from young sedentary rats, but reduced myogenic constriction in arterioles from young exercise-trained rats. In contrast, endothelial removal had no effect on myogenic constriction of arterioles from old exercise-trained rats, but increased myogenic vasoconstriction in old sedentary rats. The effect of Kv1 channel blockade was also dependent on age and training status. In arterioles from young sedentary rats, Kv1 blockade had little effect on myogenic constriction, whereas in old sedentary rats Kv1 blockade increased myogenic constriction. After exercise training, Kv1 channel blockade increased myogenic constriction in arterioles from both young and old rats. Thus exercise training restores myogenic constriction of arterioles from old rats and enhances myogenic constriction from young rats through adaptations of the endothelium and smooth muscle Kv1 channels.
Pharyngeal mucosal wall folds in subjects with obstructive sleep apnea
Authors: Kairaitis Kristina , Foster Sheryl , Amatoury Jason , Verma Manisha , Wheatley John R. , Amis Terence C.
Published: January 2015

Mechanical processes underlying pharyngeal closure have not been examined. We hypothesized that the pharyngeal mucosal surface would fold during closure, and lowering the upper airway lining liquid surface tension would unfold areas of mucosal apposition, i.e., folds. We compared baseline pharyngeal fold numbers and response to reduction in upper airway liquid surface tension in healthy and obstructive sleep apnea (OSA) subjects. Awake, gated magnetic resonance pharyngeal airway images of 10 healthy and 11 OSA subjects were acquired before and after exogenous surfactant administration (beractant). Upper airway liquid surface tension was measured at the beginning and end of image acquisition and averaged. Velopharyngeal and oropharyngeal images were segmented and analyzed separately for average cross-sectional area, circumference, and fold number. Compared with healthy subjects, at baseline, velopharynx for OSA subjects had a smaller cross-sectional area (98.3 ± 32.5 mm2 healthy, 52.3 ± 23.6 mm2 OSA) and circumference (46.5 ± 8.1 mm healthy, 30.8 ± 6.1 mm OSA; both P < 0.05, unpaired t-test), and fewer folds (4.9 ± 1.6 healthy, 3.1 ± 1.8 OSA, P < 0.03). There were no differences in oropharynx for cross-sectional area, circumference, or folds. Reduction in upper airway liquid surface tension from 61.3 ± 1.2 to 55.3 ± 1.5 mN/m ( P < 0.0001) did not change cross-sectional area or circumference for velopharynx or oropharynx in either group; however, in OSA subjects, oropharyngeal folds fell from 6.8 ± 3.1 to 4.7 ± 1.2 ( n = 8, P < 0.05), and velopharyngeal folds from 3.3 ± 1.9 to 2.3 ± 1.2 ( P = 0.08), and were unchanged in healthy subjects. Subjects with OSA have fewer velopharyngeal wall folds, which decrease further when surface tension falls. We speculate that reduced pharyngeal wall folds contribute to an increase in pharyngeal collapsibility.
The superior precentral gyrus of the insula does not appear to be functionally specialized for articulation
Authors: Fedorenko Evelina , Fillmore Paul , Smith Kimberly , Bonilha Leonardo , Fridriksson Julius
Published: January 2015

Broca (Broca P. Bull Soc Anat Paris 36: 330–357, 1861) influentially argued that posterior left inferior frontal gyrus supports speech articulation. According to an alternative proposal (e.g., Dronkers NF. Nature 384: 159–161, 1996; Wise RJ, Greene J, Buchel C, Scott SK. Lancet 353: 1057–1061, 1999; Baldo JV, Wilkins DP, Ogar J, Willock S, Dronkers NF. Cortex 47: 800–807, 2011), a region in the anterior insula [specifically, the superior precentral gyrus of the insula (SPGI)] is the seat of articulatory abilities. Moreover, Dronkers and colleagues have argued that the SPGI is functionally specialized for (complex) speech articulation. Here, we evaluate this claim using individual-subject functional MRI (fMRI) analyses (e.g., Fedorenko E, Hsieh PJ, Nieto-Castanon A, Whitfield-Gabrieli S, Kanwisher N. J Neurophysiol 104: 1177–1194, 2010). We find that the SPGI responds weakly, if at all, during articulation (parts of Broca's area respond 3–4 times more strongly) and does not show a stronger response to higher articulatory demands. This holds regardless of whether the SPGI is defined functionally (by selecting the most articulation-responsive voxels in the vicinity of the SPGI in each subject individually) or anatomically (by using masks drawn on each individual subject's anatomy). Critically, nonspeech oral movements activate the SPGI more strongly than articulation, especially under the anatomical definition of the SPGI. In line with Hillis et al. (Hillis AE, Work M, Barker PB, Jacobs MA, Breese EL, Maurer K. Brain 127: 1479–1487, 2004; also Trupe L, Varma DD, Gomez Y, Race D, Leigh R, Hillis AE, Gottesman RF. Stroke 44: 740–744, 2013), we argue that previous links between the SPGI, and perhaps anterior insula more generally, and articulation may be due to its high base rate of ischemic damage (and activation in fMRI; Yarkoni T, Poldrack RA, Nichols TE, Van Essen DC, Wager TD. Nat Methods 8: 665–670, 2011), combined with its proximity to regions that more directly support speech articulation, such as the precentral gyrus or the posterior aspects of the inferior frontal gyrus (Richardson JD, Fillmore P, Rorden C, Lapointe LL, Fridriksson J. Brain Lang 123: 125–130, 2012), and thus susceptibility to joint damage.