bluuebunny/crossref_metadata_2025 huggingface dataset:
Hair regrowth through wound healing process after ablative fractional laser treatment in a murine model
Authors: Bae Jung Min , Jung Han Mi , Goo Boncheol , Park Young Min
Published: May 2015

Background and Objective

Alopecia is one of the most common dermatological problems in the elderly; however, current therapies for it are limited by low efficacy and undesirable side effects. Although clinical reports on fractional laser treatment for various alopecia types are increasing, the exact mechanism remains to be clarified. The purposes of this study were to demonstrate the effect of ablative fractional laser treatment on hair follicle regrowth in vivo and investigate the molecular mechanism after laser treatment.

Materials and Methods

Ablative CO2 fractional laser was applied to the shaved dorsal skin of 7‐week‐old C57BL/6 mice whose hair was in the telogen stage. After 12 mice were treated at various energy (10–40 mJ/spot) and density (100–400 spots/cm2) settings to determine the proper dosage for maximal effect. Six mice were then treated at the decided dosage and skin specimens were sequentially obtained by excision biopsy from the dorsal aspect of each mouse. Tissue samples were used for the immunohistochemistry and reverse transcription polymerase chain reaction assays to examine hair follicle status and their related molecules.

Results

The most effective dosage was the 10 mJ/spot and 300 spots/cm2 setting. The anagen conversion of hair was observed in the histopathological examination, while Wnt/β‐catenin expression was associated with hair regrowth in the immunohistochemistry and molecular studies.

Conclusions

Ablative fractional lasers appear to be effective for inducing hair regrowth via activation of the Wnt/β‐catenin pathway in vivo. Our findings indicate that fractional laser treatment can potentially be developed as new treatment options for stimulating hair regrowth. Lasers Surg. Med. 47:433–440, 2015. © 2015 Wiley Periodicals, Inc.
Area‐preserving curvature flow of one‐dimensional graphs and application to smoothing of dynamic PET data
Authors: Baker Charles
Published: May 2015

We design two area‐preserving curvature flows of one‐dimensional graphs and analyse the asymptotic shape of the solutions. An application to the smoothing of curves generated in dynamic positron emission tomography (PET) is also presented.
Properties of analytic Morrey spaces and applications
Authors: Liu Junming , Lou Zengjian
Published: May 2015

In this note, we aim to study analytic Morrey spaces . We first give the canonical factorization for . Then by applying p‐Carleson measure, we prove an atomic decomposition theorem of . As an application of the decomposition theorem, the interpolation problem of is solved. Finally, we show the boundedness and compactness of Toeplitz operators on .
Iterative approximation of fixed points of Prešić operators on partial metric spaces
Authors: Ilić Dejan , Abbas Mujahid , Nazir Talat
Published: May 2015

We study the convergence of the Prešić typek‐step iterative method for a class of operatorssatisfying Prešić type contractive conditions on the setting of partial metric spaces. Some examples are presented to illustrate our obtained results. As applications of the presented convergence theorems, we derive global attractivity results for a class of matrix difference equations. Numerical experiments are also presented to illustrate the theoretical findings.
Applying mass spectrometry to study non‐covalent biomolecule complexes
Authors: Chen Fan , Gülbakan Basri , Weidmann Simon , Fagerer Stephan R. , Ibáñez Alfredo J. , Zenobi Renato
Published: May 2015

Non‐covalent interactions are essential for the structural organization of biomacromolecules and play an important role in molecular recognition processes, such as the interactions between proteins, glycans, lipids, DNA, and RNA. Mass spectrometry (MS) is a powerful tool for studying of non‐covalent interactions, due to the low sample consumption, high sensitivity, and label‐free nature. Nowadays, native‐ESI MS is heavily used in studies of non‐covalent interactions and to understand the architecture of biomolecular complexes. However, MALDI‐MS is also becoming increasingly useful. It is challenging to detect the intact complex without fragmentation when analyzing non‐covalent interactions with MALDI‐MS. There are two methodological approaches to do so. In the first approach, different experimental and instrumental parameters are fine‐tuned in order to find conditions under which the complex is stable, such as applying non‐acidic matrices and collecting first‐shot spectra. In the second approach, the interacting species are “artificially” stabilized by chemical crosslinking. Both approaches are capable of studying non‐covalently bound biomolecules even in quite challenging systems, such as membrane protein complexes. Herein, we review and compare native‐ESI and MALDI MS for the study of non‐covalent interactions. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 35: 48–70, 2016.
Postprandial Dysmetabolism and Oxidative Stress in Type 2 Diabetes: Pathogenetic Mechanisms and Therapeutic Strategies
Authors: Sottero Barbara , Gargiulo Simona , Russo Isabella , Barale Cristina , Poli Giuseppe , Cavalot Franco
Published: May 2015

Postprandial dysmetabolism in type 2 diabetes (T2D) is known to impact the progression and evolution of this complex disease process. However, the underlying pathogenetic mechanisms still require full elucidation to provide guidance for disease prevention and treatment. This review focuses on the marked redox changes and inflammatory stimuli provoked by the spike in blood glucose and lipids in T2D individuals after meals. All the causes of exacerbated postprandial oxidative stress in T2D were analyzed, also considering the consequence of enhanced inflammation on vascular damage. Based on this in‐depth analysis, current strategies of prevention and pharmacologic management of T2D were critically reexamined with particular emphasis on their potential redox‐related rationale.
Application of flow sensitive gradients for improved measures of metabolism using hyperpolarized 13c MRI
Authors: Gordon Jeremy W. , Niles David J. , Adamson Erin B. , Johnson Kevin M. , Fain Sean B.
Published: May 2015

Purpose

To develop the use of bipolar gradients to suppress partial‐volume and flow‐related artifacts from macrovascular, hyperpolarized spins.

Theory and Methods

Digital simulations were performed over a range of spatial resolutions and gradient strengths to determine the optimal bipolar gradient strength and duration to suppress flowing spins while minimizing signal loss from static tissue. In vivo experiments were performed to determine the efficacy of this technique to suppress vascular signal in the study of hyperpolarized [1‐13C]pyruvate renal metabolism.

Results

Digital simulations showed that in the absence of bipolar gradients, partial‐volume artifacts from the vasculature were still present, causing underestimation of the apparent reaction rate of pyruvate to lactate (kP). The addition of a bipolar gradient with b = 32 s/mm2 sufficiently suppressed the vascular signal without a substantial decrease in signal from static tissue. In vivo results corroborate digital simulations, with similar peak lactate signal to noise ratio (SNR) but substantially different kP in the presence of bipolar gradients.

Conclusion

The proposed approach suppresses signal from flowing spins while minimizing signal loss from static tissue, removing contaminating signal from the vasculature and increasing kinetic modeling accuracy without substantially sacrificing SNR or temporal resolution. Magn Reson Med 75:1242–1248, 2016. © 2015 Wiley Periodicals, Inc.
High temporal resolution dynamic MRI and arterial input function for assessment of GFR in pediatric subjects
Authors: Yoruk Umit , Saranathan Manojkumar , Loening Andreas M. , Hargreaves Brian A. , Vasanawala Shreyas S.
Published: May 2015

Purpose

To introduce a respiratory‐gated high‐spatiotemporal‐resolution dynamic‐contrast‐enhanced MRI technique and a high‐temporal‐resolution aortic input function (HTR‐AIF) estimation method for glomerular filtration rate (GFR) assessment in children.

Methods

A high‐spatiotemporal‐resolution DCE‐MRI method with view‐shared reconstruction was modified to incorporate respiratory gating, and an AIF estimation method that uses a fraction of the k‐space data from each respiratory period was developed (HTR‐AIF). The method was validated using realistic digital phantom simulations and demonstrated on clinical subjects. The GFR estimates using HTR‐AIF were compared with estimates obtained by using an AIF derived directly from the view‐shared images.

Results

Digital phantom simulations showed that using the HTR‐AIF technique gives more accurate AIF estimates (RMSE = 0.0932) compared with the existing estimation method (RMSE = 0.2059) that used view‐sharing (VS). For simulated GFR > 27 mL/min, GFR estimation error was between 32% and 17% using view‐shared AIF, whereas estimation error was less than 10% using HTR‐AIF. In all clinical subjects, the HTR‐AIF method resulted in higher GFR estimations than the view‐shared method.

Conclusion

The HTR‐AIF method improves the accuracy of both the AIF and GFR estimates derived from the respiratory‐gated acquisitions, and makes GFR estimation feasible in free‐breathing pediatric subjects. Magn Reson Med 75:1301–1311, 2016. © 2015 Wiley Periodicals, Inc.
Volumetric spiral chemical shift imaging of hyperpolarized [2‐13c]pyruvate in a rat c6 glioma model
Authors: Park Jae Mo , Josan Sonal , Jang Taichang , Merchant Milton , Watkins Ron , Hurd Ralph E. , Recht Lawrence D. , Mayer Dirk , Spielman Daniel M.
Published: May 2015

Purpose

MRS of hyperpolarized [2‐13C]pyruvate can be used to assess multiple metabolic pathways within mitochondria as the 13C label is not lost with the conversion of pyruvate to acetyl‐CoA. This study presents the first MR spectroscopic imaging of hyperpolarized [2‐13C]pyruvate in glioma‐bearing brain.

Methods

Spiral chemical shift imaging with spectrally undersampling scheme (1042 Hz) and a hard‐pulse excitation was exploited to simultaneously image [2‐13C]pyruvate, [2‐13C]lactate, and [5‐13C]glutamate, the metabolites known to be produced in brain after an injection of hyperpolarized [2‐13C]pyruvate, without chemical shift displacement artifacts. A separate undersampling scheme (890 Hz) was also used to image [1‐13C]acetyl‐carnitine. Healthy and C6 glioma‐implanted rat brains were imaged at baseline and after dichloroacetate administration, a drug that modulates pyruvate dehydrogenase kinase activity.

Results

The baseline metabolite maps showed higher lactate and lower glutamate in tumor as compared to normal‐appearing brain. Dichloroacetate led to an increase in glutamate in both tumor and normal‐appearing brain. Dichloroacetate‐induced %‐decrease of lactate/glutamate was comparable to the lactate/bicarbonate decrease from hyperpolarized [1‐13C]pyruvate studies. Acetyl‐carnitine was observed in the muscle/fat tissue surrounding the brain.

Conclusion

Robust volumetric imaging with hyperpolarized [2‐13C]pyruvate and downstream products was performed in glioma‐bearing rat brains, demonstrating changes in mitochondrial metabolism with dichloroacetate. Magn Reson Med 75:973–984, 2016. © 2015 Wiley Periodicals, Inc.
MRS thermometry calibration at 3 T: effects of protein, ionic concentration and magnetic field strength
Authors: Babourina‐Brooks Ben , Simpson Robert , Arvanitis Theodoros N. , Machin Graham , Peet Andrew C. , Davies Nigel P.
Published: May 2015

MRS thermometry has been utilized to measure temperature changes in the brain, which may aid in the diagnosis of brain trauma and tumours. However, the temperature calibration of the technique has been shown to be sensitive to non‐temperature‐based factors, which may provide unique information on the tissue microenvironment if the mechanisms can be further understood. The focus of this study was to investigate the effects of varied protein content on the calibration of MRS thermometry at 3 T, which has not been thoroughly explored in the literature. The effects of ionic concentration and magnetic field strength were also considered. Temperature reference materials were controlled by water circulation and freezing organic fixed‐point compounds (diphenyl ether and ethylene carbonate) stable to within 0.2 °C. The temperature was measured throughout the scan time with a fluoro‐optic probe, with an uncertainty of 0.16 °C. The probe was calibrated at the National Physical Laboratory (NPL) with traceability to the International Temperature Scale 1990 (ITS‐90). MRS thermometry measures were based on single‐voxel spectroscopy chemical shift differences between water and N‐acetylaspartate (NAA), Δ(H20‐NAA), using a Philips Achieva 3 T scanner. Six different phantom solutions with varying protein or ionic concentration, simulating potential tissue differences, were investigated within a temperature range of 21–42 °C. Results were compared with a similar study performed at 1.5 T to observe the effect of field strengths. Temperature calibration curves were plotted to convert Δ(H20‐NAA) to apparent temperature. The apparent temperature changed by −0.2 °C/% of bovine serum albumin (BSA) and a trend of 0.5 °C/50 mM ionic concentration was observed. Differences in the calibration coefficients for the 10% BSA solution were seen in this study at 3 T compared with a study at 1.5 T. MRS thermometry may be utilized to measure temperature and the tissue microenvironment, which could provide unique unexplored information for brain abnormalities and other pathologies. Copyright © 2015 John Wiley & Sons, Ltd.
A simple approach to evaluate the kinetic rate constant for ATP synthesis in resting human skeletal muscle at 7 T
Authors: Ren Jimin , Sherry A. Dean , Malloy Craig R.
Published: May 2015

Inversion transfer (IT) is a well‐established technique with multiple attractive features for analysis of kinetics. However, its application in measurement of ATP synthesis rate in vivo has lagged behind the more common saturation transfer (ST) techniques. One well‐recognized issue with IT is the complexity of data analysis in comparison with much simpler analysis by ST. This complexity arises, in part, because the γ‐ATP spin is involved in multiple chemical reactions and magnetization exchanges, whereas Pi is involved in a single reaction, Pi → γ‐ATP. By considering the reactions involving γ‐ATP only as a lumped constant, the rate constant for the reaction of physiological interest, kPi→γATP, can be determined. Here, we present a new IT data analysis method to evaluate kPi→γATP using data collected from resting human skeletal muscle at 7 T. The method is based on the basic Bloch–McConnell equation, which relates kPi→γATP to
, the rate of Pi magnetization change. The kPi→γATP value is accessed from
data by more familiar linear correlation approaches. For a group of human subjects (n = 15), the kPi→γATP value derived for resting calf muscle was 0.066 ± 0.017 s−1, in agreement with literature‐reported values. In this study we also explored possible time‐saving strategies to speed up data acquisition for kPi→γATP evaluation using simulations. The analysis indicates that it is feasible to carry out a 31P IT experiment in about 10 min or less at 7 T with reasonable outcome in kPi→γATP variance for measurement of ATP synthesis in resting human skeletal muscle. We believe that this new IT data analysis approach will facilitate the wide acceptance of IT to evaluate ATP synthesis rate in vivo. Copyright © 2015 John Wiley & Sons, Ltd.
Addressing spontaneous signal voids in repetitive single‐shot DWI of musculature: spatial and temporal patterns in the calves of healthy volunteers and consideration of unintended muscle activities as underlying mechanism
Authors: Steidle Günter , Schick Fritz
Published: May 2015

Single‐shot diffusion‐weighted MRI sensitive to different types of incoherent motion inside tissue shows sporadic signal voids with a considerable size (>1 cm) in calf musculature at rest. Spatial and temporal patterns of these signal voids and their dependence on measurement conditions were tested systematically in order to obtain more insight into the underlying mechanism. Lower leg muscles of 10 healthy subjects were examined by recording series of 1000 echo‐planar single‐shot scans with repetition time 500 ms and b‐value 100 s/mm2. Effects of strength and orientation of motion sensitization gradients and of repetition times were analysed. Potential influences of arterial blood pulsations and positioning of the subject were studied. Comparison of calf muscle groups showed more frequent signal voids in gastrocnemius and soleus muscle compared with tibialis muscles. Large inter‐individual variance in the total number of signal voids visible in a transverse slice of the lower leg was observed (minimum 40/1000 scans; maximum >550/1000 scans). Typical sizes of the affected muscular areas ranged from 1.5 to 2.5 cm in the transverse and from 1.5 to 7 cm in the head–feet direction. Signal voids occurred nearly independent of the cardiac phase and with similar frequencies for supine and prone positions. Resting calf muscles show spontaneous signal voids in single‐shot DWI at low b‐values with an irregular temporal and spatial pattern. Values of mean diffusivity, diffusion tensor parameters, and IVIM‐derived perfusion are expected to be clearly distorted by such signal voids if no rejection of affected data is applied. Several potential causes for the signal voids are discussed. The most probable explanation for the phenomenon is seen in the occurrence of spontaneous incoherent mechanical activity in musculature based on weak muscle fibre contractions. If this is the case it opens up a new field for studies on the physiological role and regulation of these unintended muscle activities. Copyright © 2015 John Wiley & Sons, Ltd.
Digital signature to help network management using flow analysis
Authors: Proença Mario Lemes , Fernandes Gilberto , Carvalho Luiz F. , de Assis Marcos V. O. , Rodrigues Joel J. P. C.
Published: May 2015

Because of constant growth in proportion and complexity of networks, flow analysis has become an indispensable tool for network management mechanisms. Through this resource, a traffic characterization, called digital signature of network segment using flow analysis (DSNSF), is accomplished. The models used for this purpose are the ant colony optimization metaheuristic, the Holt–Winters forecasting method and the statistical procedure, principal component analysis. The obtained DSNSF by each model is compared with the actual traffic of packets and bits and then subjected to specific evaluations in order to measure its accuracy. The experimental results show that the three methods could achieve good correlation indices and low normalized mean square error values between the DSNSF curve and the real traffic movement, indicating a good adaptability and efficiency in characterizing a network traffic segment. Copyright © 2015 John Wiley & Sons, Ltd.
An enriched FEM technique for modeling hydraulically driven cohesive fracture propagation in impermeable media with frictional natural faults: Numerical and experimental investigations
Authors: Khoei A. R. , Hirmand M. , Vahab M. , Bazargan M.
Published: May 2015

In this paper, an enriched finite element technique is presented to simulate the mechanism of interaction between the hydraulic fracturing and frictional natural fault in impermeable media. The technique allows modeling the discontinuities independent of the finite element mesh by introducing additional DOFs. The coupled equilibrium and flow continuity equations are solved using a staggered Newton solution strategy, and an algorithm is proposed on the basis of fixed‐point iteration concept to impose the flow condition at the hydro‐fracture mouth. The cohesive crack model is employed to introduce the nonlinear fracturing process occurring ahead of the hydro‐fracture tip. Frictional contact is modeled along the natural fault using the penalty method within the framework of plasticity theory of friction. Moreover, an experimental investigation is carried out to perform the hydraulic fracturing experimental test in fractured media under plane strain condition. The results of several numerical and experimental simulations are presented to verify the accuracy and robustness of the proposed computational algorithm as well as to investigate the mechanisms of interaction between the hydraulically driven fracture and frictional natural fault. Copyright © 2015 John Wiley & Sons, Ltd.
CXCR2 inhibition suppresses acute and chronic pancreatic inflammation
Authors: Steele Colin W , Karim Saadia A , Foth Mona , Rishi Loveena , Leach Joshua DG , Porter Ross J , Nixon Colin , Jeffry Evans TR , Carter C Ross , Nibbs Robert JB , Sansom Owen J , Morton Jennifer P
Published: May 2015

Pancreatitis is a significant clinical problem and the lack of effective therapeutic options means that treatment is often palliative rather than curative. A deeper understanding of the pathogenesis of both acute and chronic pancreatitis is necessary to develop new therapies. Pathological changes in pancreatitis are dependent on innate immune cell recruitment to the site of initial tissue damage, and on the coordination of downstream inflammatory pathways. The chemokine receptor CXCR2 drives neutrophil recruitment during inflammation, and to investigate its role in pancreatic inflammation, we induced acute and chronic pancreatitis in wild‐type and Cxcr2−/− mice. Strikingly, Cxcr2−/− mice were strongly protected from tissue damage in models of acute pancreatitis, and this could be recapitulated by neutrophil depletion or by the specific deletion of Cxcr2 from myeloid cells. The pancreata of Cxcr2−/− mice were also substantially protected from damage during chronic pancreatitis. Neutrophil depletion was less effective in this model, suggesting that CXCR2 on non‐neutrophils contributes to the development of chronic pancreatitis. Importantly, pharmacological inhibition of CXCR2 in wild‐type mice replicated the protection seen in Cxcr2−/− mice in acute and chronic models of pancreatitis. Moreover, acute pancreatic inflammation was reversible by inhibition of CXCR2. Thus, CXCR2 is critically involved in the development of acute and chronic pancreatitis in mice, and its inhibition or loss protects against pancreatic damage. CXCR2 may therefore be a viable therapeutic target in the treatment of pancreatitis. © 2015 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Event Prediction With Learning Algorithms—A Study of Events Surrounding the Egyptian Revolution of 2011 on the Basis of Micro Blog Data
Authors: Boecking Benedikt , Hall Margeret , Schneider Jeff
Published: May 2015

We aim to predict activities of political nature influencing or reflecting societal‐scale behavior and beliefs by applying learning algorithms to Twitter data. This study focuses on capturing domestic events in Egypt from November 2009 to November 2013. To this extent we study un­derlying communication patterns by evaluating content and metadata of 1.3 million tweets through computationally supported classification, with­out targeting specific keywords or users from the Twitter stream. Support Vector Machine (SVM) and Support Distribution Machine (SDM) classification algorithms are applied to detect and predict societal‐scale unrest. Latent Dirichlet Allocation (LDA) is used to create content‐based input patterns for the SVM while the SDM is used to classify sets of features created from meta‐data. The experiments reveal that user cen­tric approaches based on meta‐data outperform methods employing content‐based input despite the use of well established natural language pro­cessing algorithms. The results show that distri­butions over user centric meta information pro­vide an important signal when detecting and pre­dicting events. Applying this approach can assist policymakers and stakeholders in their efforts toward proactive community management.
A call to action—next steps for vision 20/20
Authors: McCavit Jack , Berger Scott , Grounds Cheryl , Nara Louisa
Published: May 2015

Process safety protects and enhances our individual health, our company's success, and our region's business economy. Companies that handle toxic, flammable, and explosive materials understand the importance of process safety and risk management. So do regulators. So should the community and other stakeholders. Individually, these stakeholders have been working for years to improve process safety performance. Accidents continue to occur. It is time to leverage our resources, knowledge, and skills to all strive for a common goal of great process safety performance. CCPS's Vision 20/20 describes that vision, which calls for effort from individual companies and effort that goes well beyond any individual company, indeed beyond the industries. © 2015 American Institute of Chemical Engineers Process Saf Prog 34: 111–118, 2015
An effective visualization technique for depth perception in augmented reality‐based surgical navigation
Authors: Choi Hyunseok , Cho Byunghyun , Masamune Ken , Hashizume Makoto , Hong Jaesung
Published: May 2015

Background

Depth perception is a major issue in augmented reality (AR)‐based surgical navigation. We propose an AR and virtual reality (VR) switchable visualization system with distance information, and evaluate its performance in a surgical navigation set‐up.

Methods

To improve depth perception, seamless switching from AR to VR was implemented. In addition, the minimum distance between the tip of the surgical tool and the nearest organ was provided in real time. To evaluate the proposed techniques, five physicians and 20 non‐medical volunteers participated in experiments.

Results

Targeting error, time taken, and numbers of collisions were measured in simulation experiments. There was a statistically significant difference between a simple AR technique and the proposed technique.

Conclusions

We confirmed that depth perception in AR could be improved by the proposed seamless switching between AR and VR, and providing an indication of the minimum distance also facilitated the surgical tasks. Copyright © 2015 John Wiley & Sons, Ltd.
Reducing Monte Carlo error in the Bayesian estimation of risk ratios using log‐binomial regression models
Authors: Salmerón Diego , Cano Juan A. , Chirlaque María D.
Published: May 2015

In cohort studies, binary outcomes are very often analyzed by logistic regression. However, it is well known that when the goal is to estimate a risk ratio, the logistic regression is inappropriate if the outcome is common. In these cases, a log‐binomial regression model is preferable. On the other hand, the estimation of the regression coefficients of the log‐binomial model is difficult owing to the constraints that must be imposed on these coefficients. Bayesian methods allow a straightforward approach for log‐binomial regression models and produce smaller mean squared errors in the estimation of risk ratios than the frequentist methods, and the posterior inferences can be obtained using the software WinBUGS. However, Markov chain Monte Carlo methods implemented in WinBUGS can lead to large Monte Carlo errors in the approximations to the posterior inferences because they produce correlated simulations, and the accuracy of the approximations are inversely related to this correlation. To reduce correlation and to improve accuracy, we propose a reparameterization based on a Poisson model and a sampling algorithm coded in R. Copyright © 2015 John Wiley & Sons, Ltd.
Climate change tipping points: origins, precursors, and debates
Authors: Russill Chris
Published: May 2015

The article reviews the origins, precursors, and main proponents of climate change tipping points, and the debates that the tipping point concept has occasioned. The importance of dynamical systems theory,GAIAtheory, and abrupt climate change to the main proponents of tipping point warning systems is noted and situated in historical context. The ‘semantic confusion’ that animates contemporary debates, it is suggested, results not simply from a narrow conception of tipping points, but from inattention to the way metaphor was used to reshape climate policy. A deeper understanding of dynamical systems theory and its origins (both mathematical and metaphorical) is recommended for addressing the value of tipping points in policy.WIREs Clim Change2015, 6:427–434. doi: 10.1002/wcc.344

This article is categorized under:

Social Status of Climate Change Knowledge > Knowledge and Practice
Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review
Authors: Kaniewski David , Guiot Joël , Van Campo Elise
Published: May 2015

One of the goals of climate scientists is to understand how climate shifts may have changed the course of history and influenced culture at millennial timescales. Repeatedly, environmental degradation has upset the balance between people, their habitat, and the socioeconomic frameworks in which they live. Among these imbalances, drought, firmly rooted in people's minds as a catalyst of harvest failures and famines, remains a permanent threat because it may trigger or amplify social crises, leading to massive exoduses, conflicts, and political turmoil. The spiral of decline in which the flourishing Eastern Mediterranean civilizations were plunged 3200 years ago, and the ensuing chaos, remains a persistent riddle in Near Eastern history. Scholars tend to believe that this socioeconomic collapse was violent and culturally disruptive. Most of the coastal cities between Pylos and Gaza were destroyed, burned, and often left unoccupied, thereafter, putting an end to the elaborate network of international trade that ensured prosperity in the Aegean and the Eastern Mediterranean. The rural settlements that emerged have mainly persisted through adapted agropastoral activities and limited long‐distance trade. At the dusk of this event, regional cultures began to be poorly documented, leading historians to allude to a dark age that lasted for 300 years. Among the roots, tectonic instability and earthquakes, demographic imbalance between social groups, internal collapses, and technological innovations are commonly evoked. However, recent studies have mainly hypothesized about an impact of a centuries‐long drought behind the decline. Drought may have hastened the fall of the Old World by sparking famine, invasions, and conflicts, leading to the political, economic, and cultural chaos termed ‘Late Bronze Age collapse’.WIREs Clim Change2015, 6:369–382. doi: 10.1002/wcc.345

This article is categorized under:

Climate, History, Society, Culture > Major Historical Eras

Paleoclimates and Current Trends > Paleoclimate
Intelligent integrated maintenance for wind power generation
Authors: Pattison D. , Segovia Garcia M. , Xie W. , Quail F. , Revie M. , Whitfield R. I. , Irvine I.
Published: May 2015

A novel architecture and system for the provision of Reliability Centred Maintenance (RCM) for offshore wind power generation is presented. The architecture was developed by conducting a bottom‐up analysis of the data required to support RCM within this specific industry, combined with a top‐down analysis of the required maintenance functionality. The architecture and system consists of three integrated modules for intelligent condition monitoring, reliability and maintenance modelling, and maintenance scheduling that provide a scalable solution for performing dynamic, efficient and cost‐effective preventative maintenance management within this extremely demanding renewable energy generation sector. The system demonstrates for the first time the integration of state‐of‐the‐art advanced mathematical techniques: Random Forests, dynamic Bayesian networks and memetic algorithms in the development of an intelligent autonomous solution. The results from the application of the intelligent integrated system illustrated the automated detection of faults within a wind farm consisting of over 100 turbines, the modelling and updating of the turbines' survivability and creation of a hierarchy of maintenance actions, and the optimizing of the maintenance schedule with a view to maximizing the availability and revenue generation of the turbines. © 2015 The Authors. Wind Energy published by John Wiley & Sons Ltd
Hybrid One‐Dimensional 15‐Crown‐5‐ether‐uranyl‐selenate Polymers in [K@(C10H20O5)][(UO2)(SeO4)(HSeO4)(H2O)]: Synthesis and Characterization
Authors: Gurzhiy Vladislav V. , Tyumentseva Olga S. , Krivovichev Sergey V. , Tananaev Ivan G.
Published: May 2015

The hybrid organic‐inorganic uranyl selenate, [K@(C10H20O5)][(UO2)(SeO4)(HSeO4)(H2O)] (I), was prepared by isothermal evaporation from aqueous solutions. The crystal structure of I [orthorhombic, Pnma, a = 15.386(3), b = 10.771(2), c = 13.239(3) Å, V = 2194.0(7) Å3, Z = 4, R1 = 0.042] is based upon complex 15‐crown‐5‐ether‐uranyl‐selenate polymeric units consisting of uranyl selenate chains decorated by [K@(15‐crown‐5)]+ complexes via strong ionic K+–O bonds. The 1D hybrid units are packed in a parquetted‐like fashion and connected to each other by hydrogen bonds and residual van der Waals interactions.
Engineering Escherichia coli for high-level production of propionate
Authors: Akawi Lamees , Srirangan Kajan , Liu Xuejia , Moo-Young Murray , Perry Chou C
Published: May 2015

Mounting environmental concerns associated with the use of petroleum-based chemical manufacturing practices has generated significant interest in the development of biological alternatives for the production of propionate. However, biological platforms for propionate production have been limited to strict anaerobes, such as Propionibacteria and select Clostridia. In this work, we demonstrated high-level heterologous production of propionate under microaerobic conditions in engineered Escherichia coli. Activation of the native Sleeping beauty mutase (Sbm) operon not only transformed E. coli to be propionogenic (i.e., propionate-producing) but also introduced an intracellular “flux competition” between the traditional C2-fermentative pathway and the novel C3-fermentative pathway. Dissimilation of the major carbon source of glycerol was identified to critically affect such “flux competition” and, therefore, propionate synthesis. As a result, the propionogenic E. coli was further engineered by inactivation or overexpression of various genes involved in the glycerol dissimilation pathways and their individual genetic effects on propionate production were investigated. Generally, knocking out genes involved in glycerol dissimilation (except glpA) can minimize levels of solventogenesis and shift more dissimilated carbon flux toward the C3-fermentative pathway. For optimal propionate production with high C3:C2-fermentative product ratios, glycerol dissimilation should be channeled through the respiratory pathway and, upon suppressed solventogenesis with minimal production of highly reduced alcohols, the alternative NADH-consuming route associated with propionate synthesis can be critical for more flexible redox balancing. With the implementation of various biochemical and genetic strategies, high propionate titers of more than 11 g/L with high yields up to 0.4 g-propionate/g-glycerol (accounting for ~50 % of dissimilated glycerol) were achieved, demonstrating the potential for industrial application. To our knowledge, this represents the most effective engineered microbial system for propionate production with titers and yields comparable to those achieved by anaerobic batch cultivation of various native propionate-producing strains of Propionibacteria.
The association between medical education accreditation and the examination performance of internationally educated physicians seeking certification in the United States
Authors: Van Zanten Marta
Published: May 2015

The purpose of this study was to investigate the performance of graduates of international medical schools who seek Educational Commission for Foreign Medical Graduates certification based on accreditation of their medical education programmes. For the self-selected population who took United States Medical Licensing Examinations during the study period (2006–2010), accreditation was associated with higher first-attempt pass rates on some examinations, especially for international medical graduates from schools located in the Caribbean region. In addition, certain essential accreditation standards were associated with better performance on all examinations. This study lends support to the value of medical education accreditation.
Knowledge about, attitudes towards, practices regarding Taenia solium cysticercosis among people attending an epilepsy clinic in India
Authors: Sankhyan Pratyaksha , Gupta Sahil , Singh Gagandeep
Published: May 2015

Background Taenia solium cysticercosis is one of the commonest, but potentially eradicable, causes of seizures in India. Eradication and appropriate control should incorporate educational interventions regarding the infestation and this requires an assessment of knowledge about, attitudes towards and practices (KAP) regarding the disorder.

Aim We undertook a KAP survey regarding T. solium cysticercosis in a hospital-based population with seizures in order to determine the existing knowledge and attitudes regarding the disorder and practices regarding its prevention and treatment.

Methods One hundred and eighty two people attending an epilepsy clinic were administered a validated 16-item KAP questionnaire, the responses of which were assessed against responses obtained from experienced neurologists.

Results Of the 182 respondents, 22 (12%) believed that a worm was responsible for their seizures, while 94 (52%) were aware of the link between worms and epilepsy in general. Despite this 150 (82%) were unsure about the name and nature of the worm. In fact 89 (49%) believed that the worm was acquired by eating cabbages rather than by consuming pork and by poor personal hygiene. Only 14 (8%) had ever consumed pork. Of note, 56 (31%) admitted visiting unqualified quacks who sucked out the worm through the nose.

Conclusions In conclusion although the population was highly sensitized to the association between worms and epilepsy they did not appreciate its mode of transmission. Moreover the practice of visiting quacks to remove worms was quite prevalent.
Reliability and validity of a Chinese version of the Modified Body Image Scale in patients with symptomatic pelvic organ prolapse
Authors: Zhu Lan , Wang Xiaoqian , Shi Honghui , Xu Tao , Lang Jinghe , Tang Xiang
Published: May 2015

Objective

To validate a Chinese version of the Modified Body Image Scale (MBIS) among patients with symptomatic pelvic organ prolapse.

Methods

As part of a validation study at a center in Beijing, China, women with symptomatic pelvic organ prolapse stage II or greater completed the Chinese version of the MBIS, the 12‐item Short‐Form Health Survey (SF‐12), and the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ‐12). A sample of 30 women was randomly chosen to return 2 weeks later to complete the questionnaires again. The reliability and validity of the MBIS were assessed.

Results

Overall, 52 patients participated. A Cronbach α of 0.926 demonstrated adequate internal consistency of the Chinese MBIS. Its reproducibility was demonstrated by intraclass correlation coefficient values of 0.554–0.963 (P < 0.01 for all items). Confirmatory factor analysis supported its construct validity. The MBIS and SF‐12 scores were negatively correlated (r = –0.390; P < 0.001), and the MBIS and PISQ‐12 scores were also negatively correlated (r = –0.709; P < 0.001).

Conclusion

The Chinese version of the MBIS is a reliable and valid tool to evaluate body image perception among patients with symptomatic pelvic organ prolapse.
Is Helicobacter pylori infection a risk factor for childhood periodic syndromes?
Authors: Erjaee A. , Haghighat M. , Ataollahi M. , Daneshbod Y.
Published: May 2015

Background and objectives:

Helicobacter pylori (H. pylori) infection has been assumed to have roles in various extra-digestive diseases. The current study was designed to evaluate the incidence of H. pylori infection in patients with cyclic vomiting syndrome and its possible role in the etiology of this disease.

Design and setting:

In this case-control study, 120 cases with diagnoses of cyclic vomiting or abdominal migraine who were registered at the Gastroenterology Clinic at Shiraz University of Medical Sciences from 2010 to 2013 were enrolled.

Materials and methods:

Primarily information regarding the patients’ diseases were collected with a data gathering sheet, and fresh morning stool samples were collected from the patients and examined for H. pylori stool antigen with the H. pylori Ag EIA test kit. The results were compared with those of healthy children from the control group.

Results:

A total of 120 patients with cyclic vomiting (47.5%) and abdominal migraine (52.5%) with a mean age of 7.1 ± 3.4 (range 2-16 years) and a male-to-female ratio of 1.6 were included. The HPs Ag tests were positive in only 7 (5.8%) patients in our case group, and the HPs Ag tests were positive in 13 (13%) of the children in the control group; this difference was statistically insignificant.

Conclusion:

Our study did not support H. pylori infection as an etiological factor in CV or AM.
A researcher's guide to regression, discretization, and median splits of continuous variables
Authors: Rucker Derek D. , McShane Blakeley B. , Preacher Kristopher J.
Published: May 2015

We comment on Iacobucci, Posavac, Kardes, Schneider, and Popovich (2015) by evaluating the practice of discretizing continuous variables. We show that dichotomizing a continuous variable via the median split procedure or otherwise and analyzing the resulting data via ANOVA involves a large number of costs that can be avoided by preserving the continuous nature of the variable and analyzing the data via linear regression. As a consequence, we recommend that regression remain the normative procedure both when the statistical assumptions explored by Iacobucci et al. hold and more generally in research involving continuous variables. We also discuss the advantages of preserving the continuous nature of the variable for graphical presentation and provide practical suggestions for such presentations.
Maternal iron status in early pregnancy and birth outcomes: insights from the Baby's Vascular health and Iron in Pregnancy study
Authors: Alwan Nisreen A. , Cade Janet E. , McArdle Harry J. , Greenwood Darren C. , Hayes Helen E. , Simpson Nigel A. B.
Published: May 2015

Fe deficiency anaemia during early pregnancy has been linked with low birth weight and preterm birth. However, this evidence comes mostly from studies measuring Hb levels rather than specific measures of Fe deficiency. The present study aimed to examine the association between maternal Fe status during the first trimester of pregnancy, as assessed by serum ferritin, transferrin receptor and their ratio, with size at birth and preterm birth. In the Baby VIP (Baby's Vascular health and Iron in Pregnancy) study, we recruited 362 infants and their mothers after delivery in Leeds, UK. Biomarkers were measured in maternal serum samples previously obtained in the first trimester of pregnancy. The cohort included sixty-four (18 %) small for gestational age (SGA) babies. Thirty-three babies were born preterm (9 %; between 34 and 37 weeks). First trimester maternal Fe depletion was associated with a higher risk of SGA (adjusted OR 2·2, 95 % CI 1·1, 4·1). This relationship was attenuated when including early pregnancy Hb in the model, suggesting it as a mediator (adjusted OR 1·6, 95 % CI 0·8, 3·2). For every 10 g/l increase in maternal Hb level in the first half of pregnancy the risk of SGA was reduced by 30 % (adjusted 95 % CI 0, 40 %); levels below 110 g/l were associated with a 3-fold increase in the risk of SGA (95 % CI 1·0, 9·0). There was no evidence of association between maternal Fe depletion and preterm birth (adjusted OR 1·5, 95 % 0·6, 3·8). The present study shows that depleted Fe stores in early pregnancy are associated with higher risk of SGA.
Late Permian mafic rocks identified within the Doba basin of southern Chad and their relationship to the boundary of the Saharan Metacraton
Authors: SHELLNUTT J. GREGORY , LEE TUNG-YI , YANG CHIH-CHENG , HU SHIN-TAI , WU JONG-CHANG , WANG KUO-LUNG , LO CHING-HUA
Published: May 2015

The Doba gabbro was collected from an exploration well through the Cretaceous Doba basin of southern Chad. The gabbro is composed mostly of plagioclase, clinopyroxene and Fe–Ti oxide minerals and displays cumulus mineral textures. Whole-rock40Ar–39Ar step-heating geochronology yielded a Late Permian plateau age of 257 ± 1 Ma. The major and trace elemental geochemistry shows that the gabbro is tholeiitic in composition and has trace element ratios (i.e. La/YbN> 7; Sm/YbPM> 3.4; Nb/Y > 1; Zr/Y > 5) indicative of a basaltic melt derived from a garnet-bearing mantle source. The moderately enriched Sr–Nd isotopes (i.e. ISr= 0.70495 to 0.70839; ɛNd(T)= −1.0 to −1.3) fall within the mantle array (i.e. OIB-like) and are similar to other Late Permian plutonic rocks of North-Central Africa (i.e. ISr= 0.7040 to 0.7070). The enriched isotopic composition of the Doba gabbro contrasts with the more depleted compositions of the spatially associated Neoproterozoic post-Pan-African within-plate granites. The contrasting Nd isotope composition between the older within-plate granites and the younger Doba gabbro indicates that different mantle sources produced the rocks and thus may mark the southern boundary of the Saharan Metacraton.
Revisiting Reputation: How Past Actions Matter in International Politics
Authors: Weisiger Alex , Yarhi-Milo Keren
Published: May 2015

Policy-makers and political scientists have long believed that states must make policy with an eye to maintaining a good reputation, especially a good reputation for resolve. Recent work, however, has argued that reputations for resolve do not form, and hence that past actions do not influence observers' behavior in subsequent interactions. This conclusion is theoretically problematic and unsupported by the evidence offered by reputation critics. In particular, juxtaposing reputation for resolve to power and interests is misleading when past actions influence observers' beliefs about interests, while the common approach of looking at crisis decision making misses the impact of reputation on general deterrence. We thus derive hypotheses about conflict onset from both the arguments of reputation critics and the logic of more standard reputation arguments, which we put to statistical test. We find that past action is closely connected to subsequent dispute initiation and that the effects of reputation generalize beyond the immediate circumstances of the past dispute. Although reputation is not all-important, leaders are well advised to consider the reputational implications of policy decisions in international conflict.
Is the Phone Mightier Than the Sword? Cellphones and Insurgent Violence in Iraq
Authors: Shapiro Jacob N. , Weidmann Nils B.
Published: May 2015

Does improved communication provided by modern cellphone technology affect the rise or fall of violence during insurgencies? A priori predictions are ambiguous; introducing cellphones can enhance insurgent communications but can also make it easier for the population to share information with counterinsurgents and creates opportunities for signals intelligence collection. We provide the first systematic micro-level test of the effect of cellphone communication on conflict using data on Iraq's cellphone network (2004–2009) and event data on violence. We show that increased mobile communications reduced insurgent violence in Iraq, both at the district level and for specific local coverage areas. The results provide support for models of insurgency that focus on noncombatants providing information as the key constraint on violent groups and highlight the fact that small changes in the transaction costs of cooperating with the government can have large macro effects on conflict.