bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring abrupt changes in satellite time series by seasonal confidence interval of regression residuals
Authors: Zhou Zeng-Guang , Hu Chang-Miao , Tang Ping , Zhang Zheng
Published: May 2016

Near real-time monitoring of abrupt changes in satellite time series is important for timely warning of land covers changes. Regression model-based method has been frequently used to detect abrupt change (outlier or anomaly) in time series data. Abrupt change is often determined by residuals test after regression. A simple and widely used residuals test technique is confidence interval (CI), which is often time-independent or constant in many studies. However, satellite time series data is characterized by seasonal variability and periodicity. Although the periodicity could be fitted well by a seasonal-trend regression model, the seasonal variability still remains in the residuals of the regression model. The seasonal variability would lead to less reliable results if abrupt changes are detected by a constant confidence interval (CCI). In order to improve the reliability of abrupt change monitoring in satellite time series, in this paper we develop a criterion namely seasonal confidence interval (SCI) of regression residuals. Experimental evaluations with some simulated and actual satellite time series data demonstrate better performance of the proposed SCI criterion than the CCI criterion for monitoring abrupt changes in satellite time series.
Wavelet-based spectral descriptors for detection of damage in sunflower seeds
Authors: Sáfadi Thelma , Kang Minkyoung , Leite Isabel C. C. , Vidaković Brani
Published: May 2016

Analysis of seeds is essential for determining seed lot quality and hence its sowing value. Although not fully objective, assessing seed quality with radiographic images has been used as alternative to standard laboratory testing. Here, we applied 2D scale-mixing non-decimated wavelet transform for automatic processing of radiographic images of sunflower seeds. From the transformed images several spectral indices are derived. These descriptors involve spectral slopes which are directly connected with the degree of image regularity. A methodology paradigm was developed to analyze the images and classify each seed as damaged or undamaged (slight, full). By considering binary and multinomial supervised classification, the rate of correct classification was found to be 82% for damaged and full seeds, and 57% for damaged, slightly damaged, and full seeds. Although in principle many different transforms can serve as a basis in deriving spectral indices, this particular transform proved out to be sensitive to image anisotropy (by its scale-mixing nature), and stable in computation (by its non-decimated nature).
Jacobi stability analysis of Rikitake system
Authors: Gupta M. K. , Yadav C. K.
Published: May 2016

We study the Rikitake system through the method of differential geometry, i.e. Kosambi–Cartan–Chern (KCC) theory for Jacobi stability analysis. For applying KCC theory we reformulate the Rikitake system as two second-order nonlinear differential equations. The five KCC invariants are obtained which express the intrinsic properties of nonlinear dynamical system. The deviation curvature tensor and its eigenvalues are obtained which determine the stability of the system. Jacobi stability of the equilibrium points is studied and obtain the conditions for stability. We study the dynamics of Rikitake system which shows the chaotic behaviour near the equilibrium points.
The ℓp-function on finite Boolean lattices
Authors: Ortega Oscar , García-Martínez C. , Adamski K.
Published: May 2016

Let [Formula: see text] be an integer such that [Formula: see text]. A [Formula: see text]-value of a sequence [Formula: see text] of elements of a finite metric space [Formula: see text] is an element [Formula: see text] for which [Formula: see text] is minimum. The [Formula: see text] function whose domain is the set of all finite sequences on [Formula: see text], and defined by [Formula: see text] is a [Formula: see text]-value of [Formula: see text] is called the [Formula: see text] function on [Formula: see text]. In this note, an axiomatic characterization of the [Formula: see text] function on finite Boolean lattices is presented.
Zk-Magic labeling of subdivision graphs
Authors: Jeyanthi P. , Daisy K. Jeya
Published: May 2016

For any nontrivial abelian group [Formula: see text] under addition a graph [Formula: see text] is said to be [Formula: see text]-magic if there exists a labeling [Formula: see text] such that the vertex labeling [Formula: see text] defined as [Formula: see text] taken over all edges [Formula: see text] incident at [Formula: see text] is a constant. An [Formula: see text]-magic graph [Formula: see text] is said to be [Formula: see text]-magic graph if the group [Formula: see text] is [Formula: see text] the group of integers modulo [Formula: see text]. These [Formula: see text]-magic graphs are referred to as [Formula: see text]-magic graphs. In this paper, we prove that the graphs such as subdivision of ladder, triangular ladder, shadow, total, flower, generalized prism, [Formula: see text]-snake, lotus inside a circle, square, gear, closed helm and antiprism are [Formula: see text]-magic graphs. Also we prove that if [Formula: see text] be [Formula: see text]-magic graphs with magic constant zero then [Formula: see text] is also [Formula: see text]-magic.
SOME RESEARCH CHALLENGES IN THE ECONOMICS OF CLIMATE CHANGE
Authors: BURKE MARSHALL , CRAXTON MELANIE , KOLSTAD CHARLES D. , ONDA CHIKARA
Published: May 2016

The paper reviews progress in understanding the economics of climate change with an emphasis on identifying promising advances that are both significant and nonmarginal, as well as areas in which there are key gaps in our knowledge. We highlight several important areas in which important policy-relevant research questions remain: improving estimates of climate damage used for determining the social cost of carbon, refining integrated assessment models, and designing better climate policies. As the world moves to understand and implement country emissions reduction pledges in the context of the UNFCCC, understanding the economics of the problem will become even more important. The hope is that the paper is not only informative for existing economists already working in climate change economics, but that it also serves as an inspiration for economists in other areas, or even those in other disciplines, on ways in which to contribute to solving the problem at hand.
Magnetic Micro/Nano Structures for Biological Manipulation
Authors: Huang Chen-Yu , Hsieh Teng-Fu , Chang Wei-Chieh , Yeh Kun-Chieh , Hsu Ming-Shinn , Chang Ching-Ray , Chen Jiann-Yeu , Wei Zung-Hang
Published: May 2016

Biomanipulation based on micro/nano structures is an attractive approach for biotechnology. To manipulate biological systems by magnetic forces, the magnetic labeling technology utilized magnetic nanoparticles (MNPs) as a common rule. Ferrofluid, well-dispersed MNPs, can be used for magnetic modification of the surface or as molds to form organized microstructures. For magnetic-based micro/nano structures, different methods to modulate magnetic field at the microscale have been developed. Specifically, this review focused on a new strategy which uses the concept of micromagnetism of patterned magnetic thin film with specific domain walls configurations to generate stable magnetic poles for cell patterning.
Surgical Technique of Corrective Osteotomy for Malunited Distal Radius Fracture Using the Computer-Simulated Patient Matched Instrument
Authors: Murase Tsuyoshi
Published: May 2016

The conventional corrective osteotomy for malunited distal radius fracture that employs dorsal approach and insertion of a trapezoidal bone graft does not always lead to precise correction or result in a satisfactory surgical outcome. Corrective osteotomy using a volar locking plate has recently become an alternative technique. In addition, the use of patient-matched instrument (PMI) via computed tomography simulation has been developed and is expected to simplify surgical procedures and improve surgical precision. The use of PMI makes it possible to accurately position screw holes prior to the osteotomy and simultaneously perform the correction and place the volar locking plate once the osteotomy is completed. The bone graft does not necessarily require a precise block form, and the problem of the extensor tendon contacting the dorsal plate is avoided. Although PMI placement and soft tissue release technique require some degree of specialized skill, they comprise a very useful surgical procedure. On the other hand, because patients with osteoporosis are at risk of peri-implant fracture, tandem ulnar shortening surgery should be considered to avoid excessive lengthening of the radius.
Management of Distal Ulnar Fracture Combined with Distal Radius Fracture
Authors: Kim Jae Kwang , Kim Jong-Oh , Koh Yong-Do
Published: May 2016

The distal ulna is composed of the ulnar styloid, ulnar head, and distal ulnar metaphyseal area. Most of distal ulnar metaphyseal fractures are associated with distal radius fractures and this incidence tends to be greater in osteoporotic elderly. Consideration of the treatment of distal ulna metaphyseal fracture should be addressed after treating a distal radius fracture. If it is stable, cast immobilization is preferred, however, if it shows malalignment or instability, an operative method should be considered. More than half of distal radius fractures are combined with an ulnar styloid fracture, and considerable cases of ulnar styloid fractures result in nonunion. However, ulnar styloid nonunion usually does not cause any problems on the wrist. Recent studies of distal radius fractures treated using a volar locking plate have reported that neither the initial displacement nor the size of a concomitant ulnar styloid fracture affects clinical outcome, which suggests surgical approaches may usually not be indicated for ulnar styloid fractures.
Endoscopic Olecranon Bursal Resection for Olecranon Bursitis: A Comparative Study for Septic and Aseptic Olecranon Bursitis
Authors: Rhyou In Hyeok , Park Kyoung Jun , Kim Kyung Chul , Lee Ji-Ho , Kim Seung Yeon
Published: May 2016

Background: Open excision of the olecranon bursa has been performed traditionally. However, surgical complications such as wound healing problems and recurrence may occur after the surgery. The purpose of this study was to report on the clinical outcomes of endoscopic olecranon bursal resection performed in both septic and aseptic olecranon bursitis.

Methods: We retrospectively reviewed 30 patients who underwent endoscopic olecranon bursal resection from June 2007 to January 2012. There were 20 males and 10 females. The ages ranged from 22 to 80 years, with an average age of 57.4 years and the average follow-up was 21.1 months (6–61.5 months). There were 15 cases in the septic group. The treatment outcome was measured according to the following; the rate of recurrence, range of motion, complications associated with surgery, VAS and QuickDASH.

Results: There were no complications such as postoperative infection or neurovascular injuries. In the septic group, the VAS and QuickDASH scores were significantly improved from 5.6 to 0.1 and from 28 to 1.3, respectively. In the aseptic group, the VAS and QuickDASH scores were improved from 0.6 to 0.1 and from 25.7 to 0.5, respectively. In all cases, there were no recurrences and no limitations of joint motion until the final follow-up.

Conclusions: We were able to obtain excellent outcomes without recurrence by performing endoscopic olecranon bursal resection in both septic and aseptic olecranon bursitis.
Salvage Procedures for Distal Radioulnar Joint Complications
Authors: Yeo Chong Jin , Morse Levi Philip , Krishnan Jeganath , Bain Gregory Ian
Published: May 2016

The distal radioulnar joint (DRUJ) allows forearm rotation and load transmission across the wrist. Post-traumatic and degenerative joint disease of DRUJ may cause pain and disability. Deficiency of the soft tissue or bony supports may result in DRUJ instability. Various techniques have been developed to address arthritis and / or instability of the DRUJ. A comprehensive review of the spectrum of surgical techniques and arthroplasty options is presented. The concepts of these procedures are discussed in detail, with a focus on special points of interest to optimise outcomes and to avoid complications. The salvage of the complications of arthroplasties is also presented in detail.
Assessment of the Accuracy of Online Information Regarding Trigger Finger
Authors: Hinds Richard M. , Gottschalk Michael B. , Muppavarapu Raghuveer C. , Naik Amish A. , Yang S. Steven , Capo John T.
Published: May 2016

Background: Review of the recent literature suggests substantial use of the Internet by patients seeking health care information despite questionable accuracy and readability of information presented on some websites. The purpose of our study was to assess the accuracy, quality, and readability of online information regarding trigger finger.

Methods: Three terms (“trigger finger”, “stenosing tenosynovitis”, and “finger locking”) were used to query three Internet search engines to evaluate websites regarding information about trigger finger. Three hand surgery fellows independently assessed website accuracy and quality using standardized scoring criteria. The Fleisch-Kincaid reading grade level score was used to assess website readability. Website authorship and commercial association were also noted.

Results: Sixty-nine unique websites were assessed. Internet information obtained using the search term “stenosing tenosynovitis” was written at a significantly higher reading level than information found using “finger locking” or “trigger finger”. Website quality and accuracy were both significantly better in websites authored by physicians compared to websites authored by non-physicians. However, website accuracy was significantly poorer in websites featuring commercial association. Additionally, websites presenting information written below the 8th grade reading level demonstrated poorer accuracy.

Conclusions: Search term has a significant effect on the readability of online information regarding trigger finger. Despite the terminology used in searches, most websites are largely inaccurate and may not be easily understandable by the general population. This demonstrates a substantial barrier to accessing accurate health care information and may impact patient outcomes. Hand surgeons should direct patients towards websites presenting accurate information with easily readable content.
Limited Wrist Arthrodesis for Scapholunate Advanced Collapse Wrist: Triangle Fixation for Four-Corner Fusion
Authors: Shintani Kosuke , Kazuki Kenichi , Takamatsu Kiyohito , Yoneda Masahiro , Uemura Takuya
Published: May 2016

Background: Limited wrist arthrodesis with scaphoid excision is a useful treatment for scapholunate advanced collapse (SLAC) of the wrist. Multiple Kirschner wires were originally used for internal fixation of the four carpal bones, however long-term cast immobilization, pin tract infection, and hardware removal are still problematic. We introduce and evaluate the clinical outcomes of an internal fixation technique; triangle fixation for four-corner fusion, using three headless screws, as an alternative to conventional multiple Kirschner wires for the treatment of SLAC wrist.

Methods: Five male patients with SLAC wrist secondary to three scaphoid nonunions and two scapholunate dissociations were treated with four-corner fusion using triangle fixation with three Double-threaded Japan screws. The mean age was 59.5 years (35–79 years) and the mean follow-up period was 40 months. After surgery, short arm splints were applied for 3–4 weeks, and then range of motion exercises were initiated.

Results: Wrist range of motion and grip strength both improved postoperatively. At the final follow-up evaluation, bone union was completely achieved and satisfactory pain relief was observed in all patients.

Conclusions: Compared with the conventional Kirschner wire technique, the present technique shortens the period of splint immobilization due to a strong compression force in a skewed position, does not require pin removal or cause pin tract infections, and provides satisfactory results.
Effect of Intraarticular Triamcinolone Acetonide Injection for Wrist Pain in Rheumatoid Arthritis Patients: A Statistical Investigation
Authors: Fukui Akihiro , Yamada Hideki , Yoshii Takashi
Published: May 2016

Background: A significant number of patients on long-term treatment and users of biologics complain of wrist pain due to synovial proliferation and arthropathic changes. Synovectomy or joint arthroplasty is often indicated for such patients, but many refuse surgery. For these patients triamcinolone acetonide was injected into the dorsum of the wrist, and evaluated the clinical benefit and safety of the wrist joint.

Methods: We injected triamcinolone acetonide into the dorsum of the wrist. We evaluated the clinical benefit and safety of intraarticular triamcinolone acetonide by analyzing data on (1) the number of injections, (2) decrease in visual analog scale pain, (3) changes in carpal height ratio, radio carpal distance ratio, and radial rotation angle in X-ray imaging, and (4) the adverse reactions of triamcinolone acetonide injection on the subcutaneous tissue and extensor tendons.

Results: 1. The number of injections per patient over 3 years 8 months was 1 for 44 wrists, 2 for 21 wrists, 3 for 17 wrists, 4 for 6 wrists, 5 for 3 wrists, 6 for 3 wrists, 7 for 2 wrists, 9 for 2 wrists, 12 for 4 wrists, and 13 for 1 wrist. 2. The overall mean VAS improved from 79 mm at baseline to 11 mm post-injection. 3. In the grade I and II group, CHS, RCDR and RRA were not statistically significant. In the grade III and IV group, CHR showed a significant decrease. 4. Neither subcutaneous atrophy nor extensor tendon rupture was reported.

Conclusions: More than 90% of patients of all disease grades responded to an average of 1 to 4 injections per year.
A Classification for Extensor Carpi Ulnaris Groove Morphology as an Aid for Ulnar Sided Wrist Pain
Authors: Singh Rohit , Patel Amit , Roulohamin Nick , Turner Rob
Published: May 2016

Background: Distal ulna groove morphology is likely to have a significant role in extensor carpi ulnaris (ECU) tendon stability. The development of a robust anatomical classification system, would be beneficial to further research into ulnar sided wrist pain and would be of use in rationalising treatment regimes.

Methods: Cadaveric specimens as well as MRI scans of patients with non-specific wrist pain were analysed independently by 3 orthopaedic surgeons twice to test the integrity of the classification system. The following classification system was developed for the distal ulna groove; Flat = L-shaped slope, S slope = S shaped, Reverse C = C-shaped slope. Findings were then subjected to Fleiss Kappa statistical analysis to evaluate how robust the classification system was.

Results: From the cadaveric arm of the study, 61 patients had their distal ulna groove morphology categorised according to types C, L, and S. For the MRI arm of the study 103 MRI scans were classified. ECU grove subtype C showed 8% dislocation compared to 33% and 47% for the L subtype and S sub type respectively.

Conclusions: Our classification system of ECU groove morphology will help identify different components to ulnar sided wrist problems and may help establish guidelines for treatment. This classification system has been validated for both cadaveric specimens and the MRI scans. It showed substantial agreement to almost perfect agreement in the data tested, thus proving good interand intra-observer reliability. It is a useful tool to help in further research into ulnar sided wrist pain and ECU instability, and may help develop further treatment strategies in the future.
Traumatic Thumb Radial Sagittal Band Injury Mimicking EPL Rupture
Authors: Dissanayake Ravi M. , Moore Peter , McCarten Gregory M.
Published: May 2016

We present the case of a closed traumatic disruption of the thumb radial sagittal band (RSB) that sonographically mimicked rupture of the extensor pollicis longus (EPL) tendon. This injury was treated with primary repair of the RSB and lead to a good functional outcome for the patient. This case report highlights how early recognition and treatment can lead to a good functional outcome.
Telco User Activity Level Prediction with Massive Mobile Broadband Data
Authors: Luo Chen , Zeng Jia , Yuan Mingxuan , Dai Wenyuan , Yang Qiang
Published: May 2016

Telecommunication (telco) operators aim to provide users with optimized services and bandwidth in a timely manner. The goal is to increase user experience while retaining profit. To do this, knowing the changing behavior patterns of users through their activity levels in advance can be a great help for operators to adjust their management strategies and reduce operational risk. To achieve this goal, the operators can make use of knowledge discovered from telco’s historical mobile broadband (MBB) records to predict mobile access activity level at an early stage. In this article, we report our research in a real-world telco setting involving more than one million telco users. Our novel contribution includes representing users as documents containing a collection of changing spatiotemporal “words” that express user behavior. By extracting users’ space-time access records in MBB data, we use latent Dirichlet allocation (LDA) to learn user-specific compact topic features for user activity level prediction. We propose a scalable online expectation-maximization (OEM) algorithm that can scale LDA to massive MBB data, which is significantly faster than several state-of-the-art online LDA algorithms. Using these real-world MBB data, we confirm high performance in user activity level prediction. In addition, we show that the inferred topics indicate that future activity level anomalies correlate highly with early skewed bandwidth supply and demand relations. Thus, our prediction system can also guide the telco operators to balance the telecommunication network in terms of supply-demand relations, saving deployment costs and energy of cell towers in the future.
High Brightness HDR Projection Using Dynamic Freeform Lensing
Authors: Damberg Gerwin , Gregson James , Heidrich Wolfgang
Published: May 2016

Cinema projectors need to compete with home theater displays in terms of image quality. High frame rate and spatial resolution as well as stereoscopic 3D are common features today, but even the most advanced cinema projectors lack in-scene contrast and, more important, high peak luminance, both of which are essential perceptual attributes of images appearing realistic. At the same time, HDR image statistics suggest that the average image intensity in a controlled ambient viewing environment such as the cinema can be as low as 1% for cinematic HDR content and not often higher than 18%,
middle gray
in photography. Traditional projection systems form images and colors by blocking the source light from a lamp, therefore attenuating between 99% and 82% of light, on average. This inefficient use of light poses significant challenges for achieving higher peak brightness levels.

In this work, we propose a new projector architecture built around commercially available components, in which light can be steered to form images. The gain in system efficiency significantly reduces the total cost of ownership of a projector (fewer components and lower operating cost), and at the same time increases peak luminance and improves black level beyond what is practically achievable with incumbent projector technologies. At the heart of this computational display technology is a new projector hardware design using phase modulation in combination with a new optimization algorithm that is capable of on-the-fly computation of freeform lens surfaces.
Ebb
Authors: Bernstein Gilbert Louis , Shah Chinmayee , Lemire Crystal , Devito Zachary , Fisher Matthew , Levis Philip , Hanrahan Pat
Published: May 2016

Designing programming environments for physical simulation is challenging because simulations rely on diverse algorithms and geometric domains. These challenges are compounded when we try to run efficiently on heterogeneous parallel architectures. We present Ebb, a Domain-Specific Language (DSL) for simulation, that runs efficiently on both CPUs and GPUs. Unlike previous DSLs, Ebb uses a three-layer architecture to separate (1) simulation code, (2) definition of data structures for geometric domains, and (3) runtimes supporting parallel architectures. Different geometric domains are implemented as libraries that use a common, unified, relational data model. By structuring the simulation framework in this way, programmers implementing simulations can focus on the physics and algorithms for each simulation without worrying about their implementation on parallel computers. Because the geometric domain libraries are all implemented using a common runtime based on relations, new geometric domains can be added as needed, without specifying the details of memory management, mapping to different parallel architectures, or having to expand the runtime’s interface.

We evaluate Ebb by comparing it to several widely used simulations, demonstrating comparable performance to handwritten GPU code where available, and surpassing existing CPU performance optimizations by up to 9 × when no GPU code exists.
Bounds on Multiple Sensor Fusion
Authors: Moran Bill , Cohen Fred , Wang Zengfu , Suvorova Sofia , Cochran Douglas , Taylor Tom , Farrell Peter , Howard Stephen
Published: May 2016

We consider the problem of fusing measurements in a sensor network, where the sensing regions overlap and data are nonnegative real numbers, possibly resulting from a count of indistinguishable discrete entities. Because of overlaps, it is generally impossible to fuse this information to arrive at an accurate value of the overall amount or count of material present in the union of the sensing regions. Here we study the computation of the range of overall values consistent with the data and provide several results. Posed as a linear programming problem, this leads to questions associated with the geometry of the sensor regions, specifically the arrangement of their nonempty intersections. We define a computational tool called the
fusion polytope
, based on the geometry of the sensing regions. Its properties are explored, and in particular, a topological necessary and sufficient condition for this to be in the positive orthant, a property that considerably simplifies calculations, is provided. We show that in two dimensions, inflated tiling schemes based on rectangular regions fail to satisfy this condition, whereas inflated tiling schemes based on hexagons do.
Involvement of a proapoptotic gene (BBC3) in islet injury mediated by cold preservation and rewarming
Authors: Omori Keiko , Kobayashi Eiji , Komatsu Hirotake , Rawson Jeffrey , Agrawal Garima , Parimi Mounika , Oancea Alina R. , Valiente Luis , Ferreri Kevin , Al-Abdullah Ismail H. , Kandeel Fouad , Takahashi Masafumi , Mullen Yoko
Published: May 2016

Long-term pancreatic cold ischemia contributes to decreased islet number and viability after isolation and culture, leading to poor islet transplantation outcome in patients with type 1 diabetes. In this study, we examined mechanisms of pancreatic cold preservation and rewarming-induced injury by interrogating the proapoptotic gene BBC3/Bbc3, also known as Puma (p53 upregulated modulator of apoptosis), using three experimental models: 1) bioluminescence imaging of isolated luciferase-transgenic (“Firefly”) Lewis rat islets, 2) cold preservation of en bloc-harvested pancreata from Bbc3-knockout (KO) mice, and 3) cold preservation and rewarming of human pancreata and isolated islets. Cold preservation-mediated islet injury occurred during rewarming in “Firefly” islets. Silencing Bbc3 by transfecting Bbc3 siRNA into islets in vitro prior to cold preservation improved postpreservation mitochondrial viability. Cold preservation resulted in decreased postisolation islet yield in both wild-type and Bbc3 KO pancreata. However, after culture, the islet viability was significantly higher in Bbc3-KO islets, suggesting that different mechanisms are involved in islet damage/loss during isolation and culture. Furthermore, Bbc3-KO islets from cold-preserved pancreata showed reduced HMGB1 (high-mobility group box 1 protein) expression and decreased levels of 4-hydroxynonenal (4-HNE) protein adducts, which was indicative of reduced oxidative stress. During human islet isolation, BBC3 protein was upregulated in digested tissue from cold-preserved pancreata. Hypoxia in cold preservation increased BBC3 mRNA and protein in isolated human islets after rewarming in culture and reduced islet viability. These results demonstrated the involvement of BBC3/Bbc3 in cold preservation/rewarming-mediated islet injury, possibly through modulating HMGB1- and oxidative stress-mediated injury to islets.
Exposure to environmentally persistent free radicals during gestation lowers energy expenditure and impairs skeletal muscle mitochondrial function in adult mice
Authors: Stephenson Erin J. , Ragauskas Alyse , Jaligama Sridhar , Redd JeAnna R. , Parvathareddy Jyothi , Peloquin Matthew J. , Saravia Jordy , Han Joan C. , Cormier Stephania A. , Bridges Dave
Published: May 2016

We have investigated the effects of in utero exposure to environmentally persistent free radicals (EPFRs) on growth, metabolism, energy utilization, and skeletal muscle mitochondria in a mouse model of diet-induced obesity. Pregnant mice were treated with laboratory-generated, combustion-derived particular matter (MCP230). The adult offspring were placed on a high-fat diet for 12 wk, after which we observed a 9.8% increase in their body weight. The increase in body size observed in the MCP230-exposed mice was not associated with increases in food intake but was associated with a reduction in physical activity and lower energy expenditure. The reduced energy expenditure in mice indirectly exposed to MCP230 was associated with reductions in skeletal muscle mitochondrial DNA copy number, lower mRNA levels of electron transport genes, and reduced citrate synthase activity. Upregulation of key genes involved in ameliorating oxidative stress was also observed in the muscle of MCP230-exposed mice. These findings suggest that gestational exposure to MCP230 leads to a reduction in energy expenditure at least in part through alterations to mitochondrial metabolism in the skeletal muscle.
Microvascular endothelial cells from preeclamptic women exhibit altered expression of angiogenic and vasopressor factors
Authors: Lee Dennis K. , Nevo Ori
Published: May 2016

Preeclampsia (PE) is a severe complication of pregnancy associated with maternal and fetal morbidity and mortality. The underlying pathophysiology involves maternal systemic vascular and endothelial dysfunction associated with circulating antiangiogenic factors, although the specific etiology of the disease remains elusive. Our aim was to investigate the maternal endothelium in PE by exploring the expression of genes involved with endothelial function in a novel platform of maternal primary endothelial cells. Adipose tissue was sampled at the time of caesarean section from both normal and preeclamptic patients. Maternal microvascular endothelial cells were isolated by tissue digestion and CD31 magnetic Dynabeads. Cell purity was confirmed by immunofluorescence microscopy and flow cytometry. Western analyses revealed VEGF activation of VEGF receptor 2 (VEGFR2) and ERK in primary cells. Quantitative PCR analyses revealed significantly altered mRNA levels of various genes involved with angiogenesis and blood pressure control in preeclamptic cells, including soluble fms-like tyrosine kinase-1, endoglin, VEGFR2, angiotensin receptor 1, and endothelin compared with cells isolated from normal pregnancies. Overall, maternal endothelial cells from preeclamptic patients exhibit extensive alteration of expression of factors associated with antiangiogenic and vasoconstrictive phenotypes, shedding light on the underlying mechanisms associated with the vascular dysfunction characteristic of PE.
Physiological role of SLC12 family members in the kidney
Authors: Bazúa-Valenti Silvana , Castañeda-Bueno María , Gamba Gerardo
Published: May 2016

The solute carrier family 12, as numbered according to Human Genome Organisation (HUGO) nomenclature, encodes the electroneutral cation-coupled chloride cotransporters that are expressed in many cells and tissues; they play key roles in important physiological events, such as cell volume regulation, modulation of the intracellular chloride concentration, and transepithelial ion transport. Most of these family members are expressed in specific regions of the nephron. The Na-K-2Cl cotransporter NKCC2, which is located in the thick ascending limb, and the Na-Cl cotransporter, which is located in the distal convoluted tubule, play important roles in salt reabsorption and serve as the receptors for loop and thiazide diuretics, respectively (Thiazide diuretics are among the most commonly prescribed drugs in the world.). The activity of these transporters correlates with blood pressure levels; thus, their regulation has been a subject of intense research for more than a decade. The K-Cl cotransporters KCC1, KCC3, and KCC4 are expressed in several nephron segments, and their role in renal physiology is less understood but nevertheless important. Evidence suggests that they are involved in modulating proximal tubule glucose reabsorption, thick ascending limb salt reabsorption and collecting duct proton secretion. In this work, we present an overview of the physiological roles of these transporters in the kidney, with particular emphasis on the knowledge gained in the past few years.
Glomerular pathology and the progression of chronic kidney disease
Authors: Lemley Kevin V.
Published: May 2016

Structural studies of the glomerulus, largely undertaken in animal models, have informed our understanding of the progression of chronic kidney disease (CKD) for decades. A fundamental tenet of that understanding is that a loss of podocytes underlies progression in many or most cases of progressive CKD. Recent attempts have been made to reconcile earlier findings from glomerular physiology (the primacy of glomerular capillary hypertension in causation of secondary glomerular sclerosis) with structural findings and have suggested a more detailed model of the mechanisms underlying podocyte detachment as viable cells. A new appreciation of the main locus of mechanical challenges to the podocyte (in the filtration slit) may both explain the renoprotective action of some current therapies and help to suggest novel therapeutic strategies.
The expression, regulation, and function of Kir4.1 (Kcnj10) in the mammalian kidney
Authors: Su Xiao-Tong , Wang Wen-Hui
Published: May 2016

Kir4.1 is an inwardly rectifying potassium (K+) channel and is expressed in the brain, inner ear, and kidney. In the kidney, Kir4.1 is expressed in the basolateral membrane of the late thick ascending limb (TAL), the distal convoluted tubule (DCT), and the connecting tubule (CNT)/cortical collecting duct (CCD). It plays a role in K+ recycling across the basolateral membrane in corresponding nephron segments and in generating negative membrane potential. The renal phenotypes of the loss-function mutations of Kir4.1 include mild salt wasting, hypomagnesemia, hypokalemia, and metabolic alkalosis, suggesting that the disruption of Kir4.1 mainly impairs the transport in the DCT. Patch-clamp experiments and immunostaining demonstrate that Kir4.1 plays a predominant role in determining the basolateral K+ conductance in the DCT. However, the function of Kir4.1 in the TAL and CNT/CCD is not essential, because K+ channels other than Kir4.1 are also expressed. The downregulation of Kir4.1 in the DCT reduced basolateral chloride (Cl−) conductance, suppressed the expression of ste20 proline-alanine-rich kinase (SPAK), and decreased Na-Cl cotransporter (NCC) expression and activity. This suggests that Kir4.1 regulates NCC expression by the modulation of the Cl−-sensitive with-no-lysine kinase–SPAK pathway.
Wnt6 regulates epithelial cell differentiation and is dysregulated in renal fibrosis
Authors: Beaton Hayley , Andrews Darrell , Parsons Martin , Murphy Mary , Gaffney Andrew , Kavanagh David , McKay Gareth J. , Maxwell Alexander P. , Taylor Cormac T. , Cummins Eoin P. , Godson Catherine , Higgins Debra F. , Murphy Paula , Crean John
Published: May 2016

Diabetic nephropathy is the most common microvascular complication of diabetes mellitus, manifesting as mesangial expansion, glomerular basement membrane thickening, glomerular sclerosis, and progressive tubulointerstitial fibrosis leading to end-stage renal disease. Here we describe the functional characterization of Wnt6, whose expression is progressively lost in diabetic nephropathy and animal models of acute tubular injury and renal fibrosis. We have shown prominent Wnt6 and frizzled 7 (FzD7) expression in the mesonephros of the developing mouse kidney, suggesting a role for Wnt6 in epithelialization. Importantly, TCF/Lef reporter activity is also prominent in the mesonephros. Analysis of Wnt family members in human renal biopsies identified differential expression of Wnt6, correlating with severity of the disease. In animal models of tubular injury and fibrosis, loss of Wnt6 was evident. Wnt6 signals through the canonical pathway in renal epithelial cells as evidenced by increased phosphorylation of GSK3β (Ser9), nuclear accumulation of β-catenin and increased TCF/Lef transcriptional activity. FzD7 was identified as a putative receptor of Wnt6. In vitro Wnt6 expression leads to de novo tubulogenesis in renal epithelial cells grown in three-dimensional culture. Importantly, Wnt6 rescued epithelial cell dedifferentiation in response to transforming growth factor-β (TGF-β); Wnt6 reversed TGF-β-mediated increases in vimentin and loss of epithelial phenotype. Wnt6 inhibited TGF-β-mediated p65-NF-κB nuclear translocation, highlighting cross talk between the two pathways. The critical role of NF-κB in the regulation of vimentin expression was confirmed in both p65−/−and IKKα/β−/−embryonic fibroblasts. We propose that Wnt6 is involved in epithelialization and loss of Wnt6 expression contributes to the pathogenesis of renal fibrosis.
Collecting duct (pro)renin receptor targets ENaC to mediate angiotensin II-induced hypertension
Authors: Peng Kexin , Lu Xiaohan , Wang Fei , Nau Adam , Chen Ren , Zhou Shu-Feng , Yang Tianxin
Published: May 2016

The (pro)renin receptor (PRR) is abundantly expressed in the collecting duct (CD) and the expression is further induced by angiotensin II (ANG II). The present study was conducted to investigate the role of CD PRR during ANG II-induced hypertension and to further explore the underlying mechanism. Radiotelemetry demonstrated that a 1-wk ANG II infusion gradually and significantly induced hypertensive response in floxed mice and this response was significantly attenuated in mice lacking PRR in the CD (termed CD PRR KO). ANG II infusion in floxed mice increased urinary renin activity and selectively induced renal medullary α-epithelial sodium channel (α-ENaC) mRNA and protein expression, all of which were blunted in the null mice. In cultured mpkCCD cells grown in Transwells, transepithelial Na+ transport as measured by using a volt-ohmmeter was transiently stimulated by acute ANG II treatment, which was abolished by a PRR antagonist, PRO20. In a chronic setting, ANG II treatment induced α-ENaC mRNA expression in mpkCCD cells, which was similarly blocked by PRO20. Chronic intramedullary infusion of an ENaC inhibitor amiloride in rats significantly attenuated ANG II-induced hypertension. Overall, the present study suggests that CD PRR contributes to ANG II-induced hypertension at least partially via activation of renal medullary ENaC.
50 Years of renal physiology from one man and the perfused tubule: Maurice B. Burg
Authors: Hamilton Kirk L. , Moore Antoni B.
Published: May 2016

Technical advancements in research techniques in science are made in slow increments. Even so, large advances from insight and hard work of an individual with a single technique can have astonishing ramifications. Here, we examine the impact of Dr. Maurice B. Burg and the isolated perfused renal tubule technique and celebrate the 50th anniversary of the publication by Dr. Burg and his colleagues of their landmark paper in the American Journal of Physiology in 1966. In this study, we have taken a scientific visualization approach to study the scientific contributions of Dr. Burg and the isolated perfused tubule preparation as determining research impact by the number of research students, postdoctoral fellows, visiting scientists, and national and international collaborators. Additionally, we have examined the research collaborations (first and second generation scientists), established the migrational visualization of the first generation scientists who worked directly with Dr. Burg, quantified the metrics indices, identified and quantified the network of coauthorship of the first generation scientists with their second generation links, and determined the citations analyses of outputs of Dr. Burg and/or his first generation collaborators as coauthors. We also review the major advances in kidney physiology that have been made with the isolated perfused tubule technique. Finally, we are all waiting for the discoveries that the isolated perfused preparation technique will bring during the next 50 years.
Estimating postvoid residual volume without measuring residual bladder volume during serial cystometrograms
Authors: Danziger Zachary C. , Grill Warren M.
Published: May 2016

The postvoid residual volume (PVR) is a common urodynamic parameter used to quantify the severity of lower urinary tract dysfunction. However, the serial cystometrograms that are typically used to assess bladder function in animal models make measuring PVR very difficult. Current approaches are to either remove PVR after each void to measure it, which is disruptive to the bladder, or to neglect the unknown contribution to PVR from ureter flow, which results in inaccurate estimates. We propose a procedure to estimate PVR during a serial cystometrogram that requires only a single measurement, rather than measuring after each void. Moreover, this measurement can occur at the end of the experiment such that it does not affect the bladder during data collection. We mathematically express PVR for all voids during a serial cystometrogram using a linear recurrence equation and use this equation to build an estimation procedure for PVR. Using in vivo measurements in urethane anesthetized rats and computer simulations we show that the estimation procedure is at least as accurate in determining PVR as the traditional method of measuring PVR after each void. Furthermore, we demonstrate the adverse effects of repeated PVR measurements in a common animal model of cystitis. Using the proposed procedure can increase the efficiency and accuracy of determining PVR for a serial cystometrogram and is less disruptive to the system under study. This, in turn, allows the calculation of other urodynamic parameters that are critical for research studies, including voiding efficiency and bladder capacity.
MAD2B-mediated SnoN downregulation is implicated in fibroblast activation and tubulointerstitial fibrosis
Authors: Tang Hui , Su Hua , Fan Di , Ye Chen , Lei Chun-Tao , Jiang Hua-Jun , Gao Pan , He Fang-Fang , Zhang Chun
Published: May 2016

MAD2B, an anaphase-promoting complex/cyclosome (APC/C) inhibitor and a small subunit of DNA polymerase ζ, is indispensible for mitotic checkpoint control and DNA repair. Previously, we established that MAD2B is expressed in glomerular and tubulointerstitial compartments and participates in high glucose-induced podocyte injury. However, its role in other renal diseases remains elusive. In the present study, we aim to illustrate the potential role of MAD2B in the pathogenesis of renal fibrosis. By immunofluorescence and Western blotting, we found MAD2B expression is obviously increased in tubulointerstitial fibrosis (TIF) patients and unilateral ureteral obstruction (UUO) mice. It is widely accepted that resident fibroblasts are the major source of collagen-producing myofibroblasts during TIF. Therefore, we evaluated the level of MAD2B in fibroblasts (NRK-49F) exposed to transforming growth factor (TGF)-β1 by immunoblotting and revealed that MAD2B is upregulated in a time-dependent manner. Intriguingly, SnoN, a transcriptional repressor of the TGF-β1/Smad signaling pathway, is decreased in TGF-β1-treated fibroblasts as well as the kidney cortex from TIF patients and UUO mice. Either in vitro or in vivo, local genetic depletion of MAD2B by lentiviral transfection could preserve SnoN abundance and suppress Smad3 phosphorylation, which finally dampens fibroblast activation, ECM accumulation, and alleviates the severity of TIF. However, the ubiquitin ligase APC/C is not involved in the MAD2B-mediated SnoN decline, although this process is ubiquitination dependent. In conclusion, our observation proposes that besides cell cycle management, MAD2B has a profibrotic role during fibroblast activation and TIF by suppressing SnoN expression. Targeting the MAD2B-SnoN pathway is a promising intervention for TIF.
Force steadiness as a predictor of time to complete a pegboard test of dexterity in young men and women
Authors: Almuklass Awad M. , Price Ryan C. , Gould Jeffrey R. , Enoka Roger M.
Published: May 2016

The purpose of the study was to evaluate the capacity of an expanded set of force steadiness tasks to explain the variance in the time it takes young men and women to complete the grooved pegboard test. In a single experimental session, 30 participants (mean ± SD) (24.2 ± 4.0 yr; 15 women) performed the grooved pegboard test, two tests of hand speed, measurements of muscle strength, and a set of submaximal, steady contractions. The steadiness tasks involved single and double actions requiring isometric contractions in the directions of wrist extension, a pinch between the index finger and thumb, and index finger abduction. Time to complete the grooved pegboard test ranged from 41.5 to 67.5 s. The pegboard times (53.9 ± 6.2 s) were not correlated with any of the strength measurements or the reaction time test of hand speed. A stepwise, multiple-regression analysis indicated that much of the variance ( R2 = 0.70) in pegboard times could be explained by a model that comprised two predictor variables derived from the steadiness tasks: time to match the target during a rapid force-matching task and force steadiness (coefficient of variation for force) during a single-action task. Moreover, the pegboard times were significantly faster for women (51.7 ± 6.8 s) than men (56.1 ± 4.9 s). Participants with slower pegboard times seemed to place a greater emphasis on accuracy than speed as they had longer times to match the target during the rapid force-matching task and exhibited superior force steadiness during the single-action task.