bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidative stress‐induced renal telomere shortening as a mechanism of cyclosporine‐induced nephrotoxicity
Authors: Raeisi Sina , Ghorbanihaghjo Amir , Argani Hassan , Dastmalchi Siavoush , Seifi Morteza , Ghasemi Babollah , Ghazizadeh Teimour , Abbasi Mehran Mesgari , Karimi Pouran 
Published: July 2018

AbstractDue to the association of oxidative stress and telomere shortening, it was aimed in the present study to investigate the possibility whether cyclosporine‐A exerts its nephrotoxic side effects via induction of oxidative stress‐induced renal telomere shortening and senescent phenotype in renal tissues of rats. Renal oxidative stress markers, 8‐hydroxydeoxyguanosine, malondialdehyde, and protein carbonyl groups were measured by standard methods. Telomere length and telomerase activity were also evaluated in kidney tissue samples. Results showed that cyclosporine‐A treatment significantly (P < 0.05) enhanced renal malondialdehyde, 8‐hydroxydeoxyguanosine, and protein carbonyl groups levels, decreased renal telomere length, and deteriorated renal function compared with the controls. Renal telomerase activity was not affected by cyclosporine‐A. Renal telomere length could be considered as an important parameter of both oxidative stress and kidney function. Telomere shortening and accelerated kidney aging may be caused by cyclosporine‐induced oxidative stress, indicating the potential mechanism of cyclosporine‐induced nephrotoxicity.
MiR‐106b regulates the apoptosis and tumorigenesis of hepatocellular carcinoma via targeting Zinc finger and BTB domain‐containing protein 7A (Zbtb7a)
Authors: Liang Xiao , Zhao Qinghua , Geng Tingting , Luo Shengshu , He Qin 
Published: July 2018

AbstractMicroRNAs play vital regulatory roles in various type of tumorigenesis. We aimed to explore the functional microRNAs that might play as therapeutic targets in hepatocellular carcinoma (HCC). In this study, our results revealed that microRNA‐106b was significantly increased in HCC tumor tissues. However, miR‐106b knockdown remarkably suppressed the growth and increased the apoptosis of Hub‐7 HCC cells. Biological analysis indicated that miR‐106b directly targeted toZinc finger and BTB domain‐containing protein 7A (Zbtb7a) to regulate the apoptosis of Hub‐7 cells. Extensively, Zbtb7a overexpression reversed Huh‐7 cell apoptosis and growth in vitro. Furthermore, in vivo studies confirmed that miR‐106b inhibition or Zbtb7a overexpression retarded the growth of Hub‐7 xenograft tumor in nude mice. In conclusion, we provide the evidence for the regulatory role of miR‐106b in HCC, which is causally linked to targeting of Zbtb7a. This study may provide miR‐106b as a potential therapeutic strategy for HCC.
The effect of astaxanthin and cadmium on rat erythrocyte G6PD, 6PGD, GR, and TrxR enzymes activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro
Authors: Bayramoğlu Akkoyun Mahire , Bengü A. Şükrü , Temel Yusuf , Akkoyun H. Turan , Ekin Suat , Ciftci Mehmet 
Published: July 2018

AbstractIn this study, the effects of astaxanthin (AST) that belongs to carotenoid family and cadmium (Cd), which is an important heavy metal, on rat erythrocyte G6PD, 6PGD, GR, and TrxR enzyme activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro were studied. In in vitro studies, 6PGD enzyme was purified from rat erythrocytes with 2′,5′‐ADP Sepharose4B affinity chromatography. Results showed inhibition of enzyme by Cd at IC50; 346.5 μM value and increase of 6PGD enzyme activity by AST. In vivo studies showed an increase in G6PD, 6PGD, and GR enzyme activities (P ˃ 0.05) and no chance in TrxR enzyme activity by AST. Cd ion inhibited G6PD, 6PGD, and GR enzyme activities (P ˂ 0.05) and also decreased TrxR enzyme activity (P ˃ 0.05). AST + Cd group G6PD enzyme activity was statistically low compared with control group (P ˂ 0.05). 6PGD and TrxR enzyme activities decreased without statistical significance (P ˃ 0.05); however, GR enzyme activity increased statistically significantly (P ˂ 0.05).
Antiapoptotic effects of vitamins C and E against cypermethrin‐induced oxidative stress and spermatogonial germ cell apoptosis
Authors: Bhardwaj Jitender Kumar , Kumari Priya , Saraf Priyanka , Yadav Abhay Singh 
Published: July 2018

AbstractToxicological studies have demonstrated the relation between use of agrochemicals and fertility issues within males. Thus, the present study aimed to elucidate the propensity of cypermethrin (CYP) in bringing testicular germ cell apoptosis and effective attenuation by vitamins C and E in caprines. Reproductive toxicity of CYP was evaluated using histomorphological, cytological, and biochemical changes in the testicular germ cells in dose‐dependent (1, 5, 10 μg/mL) and time‐dependent (4, 6, 8 h) manner. Histological and ethidium bromide/acridine orange fluorescence staining exhibited that vitamins C and E (0.5 and 1.0 mM) successfully diminished the CYP‐induced testicular germ cells apoptosis. CYP exposure along with vitamins C and E supplementation also resulted in significantly increased ferric reducing antioxidant power activity along with the antioxidant enzymes, namely catalase, superoxide dismutase, and glutathione‐s‐transferase, and decreased lipid peroxidation in testicular germ cells. Thus, vitamins C and E ameliorated CYP‐induced testicular germ cell apoptosis, thereby preventing spermatogonial cells degeneration and male infertility.
Comparison of whole‐blood tacrolimus concentrations measured by different immunoassay systems
Authors: Kaneko Tetsuya , Fujioka Takashi , Suzuki Yosuke , Nagano Toshiaki , Sato Yuhki , Asakura Syunji , Itoh Hiroki 
Published: July 2018

IntroductionDifferent measured values for tacrolimus were obtained with different automated immunoassays. We aimed to examine the differences in the blood tacrolimus concentrations measured by the major immunoassay systems commercially available in Japan.MethodsWhole‐blood samples from 118 patients were assayed by 3 commercial assays: chemiluminescent enzyme immunoassay (CLIA), affinity column‐mediated immunoassay (ACMIA), and enzyme‐multiplied immunoassay technique (EMIT). Liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) was used for reference.Key findingsThe correlation coefficient of immunoassay vs LC‐MS/MS was excellent for ACMIA (.83) and CLIA (.81) and good for EMIT (.71). The mean error was negative for ACMIA and positive for CLIA and EMIT. The mean absolute error and root‐mean‐square error were almost the same for ACMIA and CLIA and lower than those for EMIT.ConclusionsThe ACMIA and CLIA yield considerably better results than the EMIT for monitoring blood tacrolimus concentrations.
Using propensity score matching to estimate treatment effects of afterschool programs on third‐grade reading outcomes
Authors: Baker Scott K. , Kamata Akihito , Wright Annie , Farmer Dylan , Nippert Regina 
Published: July 2018

AbstractEvidence on whether afterschool programs enhance academic achievement is limited and mixed. In this study, a group of community providers delivered interventions to students to improve academic achievement. We used propensity score matching to estimate the impact of these afterschool interventions on third‐grade reading achievement. A significant effect of moderate magnitude was found favoring students who participated in afterschool programming. Propensity score matching and other methodological considerations are described to support the importance and value of conducting rigorous evaluations of afterschool programs.
Targeted profiling and relative quantification of benzoyl diterpene alkaloids in Aconitum roots by using LC–MS/MS with precursor ion scan
Authors: Gao Wen , Liu Xin‐Guang , Liu Lei , Li Ping , Yang Hua 
Published: July 2018

AbstractBenzoyl aconite alkaloids have myocardial protective effects at a low dose and produce toxic effects at high dose. Due to lack of enough reference compounds, most of the benzoyl alkaloids had few concerns, except the typical ones, i.e. aconitine, mesaconitine, and hypaconitine. To rapidly screen out and quantify benzoyl alkaloids, a high performance liquid chromatography combined with tandem mass spectrometry was proposed based on precursor ion scanning mode. First, a diagnostic ion at m/z 105 corresponding to benzoyl group was observed by using tandem mass spectrometry, which could be used for the rapid identification of benzoyl alkaloids. The targeted screening of these alkaloids was then conducted by using precursor ion scan of characteristic ion at m/z 105. Shengfuzi (the lateral root of A. carmichaelii) was taken as example, and 24 benzoyl‐containing alkaloids were identified. The six major alkaloids including aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine were determined in the precursor ion scan mode by the standard curve method. Reliable linearity, sensitivity, precision, accuracy, and repeatability were obtained and validated. Then the relative response factors between these six analytes were calculated, which were not more than two times using any alkaloid as reference. Thus, the other 18 alkaloids lacking reference compounds were relatively quantified. This approach provides a useful tool for rapid identification and quantitative analysis of toxic benzoyl alkaloids, and also an efficient method for the safety assessment of Aconitum roots.
Bioinspired Functional Gradients for Toughness Augmentation in Synthetic Polymer Systems
Authors: Chorazewicz Kayetan , Sundrani Sameer , Ahn B. Kollbe 
Published: July 2018

AbstractIn nature, load‐bearing polymeric materials that do not present significant trade‐off between elongation and elastic modulus are often found, but are rare in synthetic systems. One mechanism for emulating these natural systems is with functionally graded materials (FGMs). The development of synthetic FGM systems with varying moduli gradient using tuned poly(meth)acrylate multilayers is shown. Such localized tuning of crosslink density is shown as a mechanism to increase rigidity without significant compromise to maximum strain. The toughest FGM shows 43% higher tensile strength and 9% higher stiffness than copolymer elastomers with similar maximum strain (εmax ≈ 110%), increasing toughness by 25%. These improved tensile mechanical properties can be due to beneficial interlayer crack deflection and delamination. This gradient approach provides potential to improve toughness of various load‐bearing polymeric materials.
An Acid Test: Facile SI‐ARGET‐ATRP of Methacrylic Acid
Authors: Michl Thomas D. , Jung Dimitri , Pertoldi Andrea , Schulte Anna , Mocny Piotr , Klok Harm‐Anton , Schönherr Holger , Giles Carla , Griesser Hans J. , Coad Bryan R. 
Published: July 2018

AbstractAtom transfer radical polymerization (ATRP) of methacrylic acid (MAA) is challenging. Herein is reported a study of conditions for facile surface‐initiated ATRP by activator regenerated electron transfer (SI‐ARGET‐ATRP) growth of poly‐methacrylic acid (PMAA) chains from a plasma polymer surface bearing surface‐immobilized α‐bromoisobutyryl bromide, with no deoxygenation required. Factors that affect PMAA polymer growth off the surface under ARGET‐ATRP conditions are systematically investigated, such as monomer/catalyst ratio, solvent, and, most importantly, addition of salts and change of pH. While the concentrations of the copper catalyst and acid affect grafting, the most pronounced effect arises from the concentration of chloride ions. Adding 0.1 m NaCl and acidifying the reaction solution to pH 3 offers the best trade‐off between reaction rate and reproducibility; yielding ≈60 nm thick PMAA graft polymers in 1 h under ambient conditions. Using this easily scalable recipe and surface analysis, the grafted polymers are verified to be pure PMAA and the graft coatings to be homogenous across a substrate of 100 mm diameter.
The calculation and comparison of the Detrusor Contractility Parameter and Watts Factor
Authors: Gammie Andrew , Kitney Darryl , Drake Marcus , Abrams Paul , Fry Chris 
Published: July 2018

AimsTo test the significance of association between a validated index of detrusor contractility, vCE, the Watts Factor, and the Detrusor Contractility Parameter, t20‐80; and to test whether t20‐80 depends on outflow tract resistance as indicated by Bladder Outlet Obstruction Index (BOOI).MethodsThirty‐seven pressure‐flow traces from 20 male and 17 female patients were analyzed and forms of the Watts Factor, t20‐80 and BOOI were compared with vCE.ResultsThe Detrusor Contractility Parameter, t20‐80, is significantly associated with vCE for both women and men without a high degree of bladder outlet obstruction. The Watts Factor only had a significant association with vCE at the point of maximum flow in women.ConclusionsThe Detrusor Contractility Parameter (DCP) (t20‐80), can be measured easily from the pressure flow curves of a urodynamic test. The Watts Factor at maximum urine flow, WFQmax, can be readily calculated, but is only applicable to women. In both women and men without a high degree of bladder outlet obstruction, DCP is better associated with true detrusor contractility than any Watts Factor analysis.
Impact of contrast agent injection duration on dynamic contrast‐enhanced MRI quantification in prostate cancer
Authors: Klawer Edzo M.E. , van Houdt Petra J. , Pos Floris J. , Heijmink Stijn W.T.P.J. , van Osch Matthias J.P. , van der Heide Uulke A. 
Published: July 2018

The volume transfer constant Ktrans, which describes the leakage of contrast agent (CA) from vasculature into tissue, is the most commonly reported quantitative parameter for dynamic contrast‐enhanced (DCE‐) MRI. However, the variation in reported Ktrans values between studies from different institutes is large. One of the primary sources of uncertainty is quantification of the arterial input function (AIF). The aim of this study is to determine the influence of the CA injection duration on the AIF and tracer kinetic analysis (TKA) parameters (i.e. Ktrans, kep and ve).Thirty‐one patients with prostate cancer received two DCE‐MRI examinations with an injection duration of 5 s in the first examination and a prolonged injection duration in the second examination, varying between 7.5 s and 30 s. The DCE examination was carried out on a 3.0 T MRI scanner using a transversal T1‐weighted 3D spoiled gradient echo sequence (300 s duration, dynamic scan time of 2.5 s). Data of 29 of the 31 were further analysed. AIFs were determined from the phase signal in the left and right femoral arteries. Ktrans, kep and ve were estimated with the standard Tofts model for regions of healthy peripheral zone and tumour tissue.We observed a significantly smaller peak height and increased width in the AIF for injection durations of 15 s and longer. However, we did not find significant differences in Ktrans, kep or ve for the studied injection durations. The study demonstrates that the TKA parameters Ktrans, kep and ve, measured in the prostate, do not show a significant change as a function of injection duration.
Ammonia‐weighted imaging by chemical exchange saturation transfer MRI at 3 T
Authors: Zöllner Helge Jörn , Butz Markus , Kircheis Gerald , Klinker Stefan , Häussinger Dieter , Schmitt Benjamin , Schnitzler Alfons , Wittsack Hans‐Jörg 
Published: July 2018

Hepatic encephalopathy (HE) is triggered by liver cirrhosis and is associated with an increased ammonia level within the brain tissue. The goal of this study was to investigate effects of ammonia on in vitro amide proton transfer (APT)‐weighted chemical exchange saturation transfer (CEST) imaging in order to develop an ammonia‐sensitive brain imaging method.APT‐weighted CEST imaging was performed on phantom solutions including pure ammonia, bovine serum albumin (BSA), and tissue homogenate samples doped with various ammonia concentrations. All CEST data were assessed by magnetization transfer ratio asymmetry. In addition, optical methods were used to determine possible structural changes of the proteins in the BSA phantom. In vivo feasibility measurements were acquired in one healthy participant and two patients suffering from HE, a disease associated with increased brain ammonia levels.The CEST effect of pure ammonia showed a base‐catalyzed behavior. At pH values greater than 5.6 no CEST effect was observed. The APT‐weighted signal was significantly reduced for ammonia concentrations of 5mM or more at fixed pH values within the different protein phantom solutions. The optical methods revealed no protein aggregation or denaturation for ammonia concentrations less than 5mM. The in vivo measurements showed tissue specific and global reduction of the observed CEST signal in patients with HE, possibly linked to pathologically increased ammonia levels.APT‐weighted CEST imaging is sensitive to changes in ammonia concentrations. Thus, it seems useful for the investigation of pathologies with altered tissue ammonia concentrations such as HE. However, the underlying mechanism needs to be explored in more detail in future in vitro and in vivo investigations.
Decoupling of a double‐row 16‐element tight‐fit transceiver phased array for human whole‐brain imaging at 9.4 T
Authors: Avdievich Nikolai I. , Giapitzakis Ioannis A. , Pfrommer Andreas , Shajan Gunamony , Scheffler Klaus , Henning Anke 
Published: July 2018

One of the major challenges in constructing multi‐channel and multi‐row transmit (Tx) or transceiver (TxRx) arrays is the decoupling of the array's loop elements. Overlapping of the surface loops allows the decoupling of adjacent elements and also helps to improve the radiofrequency field profile by increasing the penetration depth and eliminating voids between the loops. This also simplifies the design by reducing the number of decoupling circuits. At the same time, overlapping may compromise decoupling by generating high resistive (electric) coupling near the overlap, which cannot be compensated for by common decoupling techniques. Previously, based on analytical modeling, we demonstrated that electric coupling has strong frequency and loading dependence, and, at 9.4 T, both the magnetic and electric coupling between two heavily loaded loops can be compensated at the same time simply by overlapping the loops. As a result, excellent decoupling was obtained between adjacent loops of an eight‐loop single‐row (1 × 8) human head tight‐fit TxRx array. In this work, we designed and constructed a 9.4‐T (400‐MHz) 16‐loop double‐row (2 × 8) overlapped TxRx head array based on the results of the analytical and numerical electromagnetic modeling. We demonstrated that, simply by the optimal overlap of array loops, a very good decoupling can be obtained without additional decoupling strategies. The constructed TxRx array provides whole‐brain coverage and approximately 1.5 times greater Tx efficiency relative to a transmit‐only/receive‐only (ToRo) array, which consists of a larger Tx‐only array and a nested tight‐fit 31‐loop receive (Rx)‐only array. At the same time, the ToRo array provides greater peripheral signal‐to‐noise ratio (SNR) and better Rx parallel performance in the head–feet direction. Overall, our work provides a recipe for a simple, robust and very Tx‐efficient design suitable for parallel transmission and whole‐brain imaging at ultra‐high fields.
Large deformation poromechanics with local mass conservation: An enriched Galerkin finite element framework
Authors: Choo Jinhyun 
Published: July 2018

SummaryNumerical modeling of large deformations in fluid‐infiltrated porous media must accurately describe not only geometrically nonlinear kinematics but also fluid flow in heterogeneously deforming pore structure. Accurate simulation of fluid flow in heterogeneous porous media often requires a numerical method that features the local (elementwise) conservation property. Here, we introduce a new finite element framework for locally mass conservative solution of coupled poromechanical problems at large strains. At the core of our approach is the enriched Galerkin discretization of the fluid mass balance equation, whereby elementwise constant functions are augmented to the standard continuous Galerkin discretization. The resulting numerical method provides local mass conservation by construction with a usually affordable cost added to the continuous Galerkin counterpart. Two equivalent formulations are developed using total Lagrangian and updated Lagrangian approaches. The local mass conservation property of the proposed method is verified through numerical examples involving saturated and unsaturated flow in porous media at finite strains. The numerical examples also demonstrate that local mass conservation can be a critical element of accurate simulation of both fluid flow and large deformation in porous media.
A probabilistic framework for multidisciplinary design: Application to the hydrostructural optimization of supercavitating hydrofoils
Authors: Bonfiglio Luca , Perdikaris Paris , del Águila Jose , Karniadakis George E. 
Published: July 2018

SummaryThe analysis and optimization of complex multiphysics systems presents a series of challenges that limit the practical use of computational tools. Specifically, the optimization of such systems involves multiple interconnected components with competing quantities of interest and high‐dimensional spaces and necessitates the use of costly high‐fidelity solvers to accurately simulate the coupled multiphysics. In this paper, we put forth a data‐driven framework to address these challenges leveraging recent advances in machine learning. We combine multifidelity Gaussian process regression and Bayesian optimization to construct probabilistic surrogate models for given quantities of interest and explore high‐dimensional design spaces in a cost‐effective manner. The synergistic use of these computational tools gives rise to a tractable and general framework for tackling realistic multidisciplinary optimization problems. To demonstrate the specific merits of our approach, we have chosen a challenging large‐scale application involving the hydrostructural optimization of three‐dimensional supercavitating hydrofoils. To this end, we have developed an automated workflow for performing multiresolution simulations of turbulent multiphase flows and multifidelity structural mechanics (combining three‐dimensional and one‐dimensional finite element results), the results of which drive our machine learning analysis in pursuit of the optimal hydrofoil shape.
Measuring carrier injection from amorphous silicon into crystalline silicon using photoluminescence
Authors: Paduthol A. , Juhl M.K. , Nogay G. , Löper P. , Trupke T. 
Published: July 2018

AbstractIn devices with intrinsic amorphous silicon layer on a crystalline silicon substrate, the light absorbed in the amorphous layer can be weakly electronically coupled into the silicon base. Such carrier injection has previously been reported from measurements on finished devices containing stacks of intrinsic and doped amorphous silicon layers. Here, we use spectral response of photoluminescence, a contactless approach, to investigate this carrier injection on significantly simpler structures. In such devices, the effect of absorption in the front layer can be measured by the internal quantum efficiency. A highly absorbing front layer is expected to cause a drop in the quantum efficiency at short wavelengths. However, if electron‐hole pairs that are generated in the front layer are subsequently injected into the base, the optical losses will be reduced, resulting in a partial recovery of the quantum efficiency at short wavelengths. Here, we quantify the efficiency of carrier injection from the intrinsic amorphous silicon front layer to the crystalline silicon base, by measuring the spectral response of photoluminescence heterojunction test structures. For devices with just an intrinsic amorphous silicon layer, the carrier injection from the layer was found to be close to unity.