bluuebunny/crossref_metadata_2025 huggingface dataset:
Negligible effect of competition on coral colony growth
Authors: Álvarez‐Noriega Mariana , Baird Andrew H. , Dornelas Maria , Madin Joshua S. , Connolly Sean R.
Published: March 2018

Competition is an important determinant of assemblage structure and population regulation, often resulting in decreased growth, fecundity or survival. In corals, most studies testing for an effect of competition on demographic traits, such as growth, have been experimental and often impose very high levels of competition upon colonies. To more realistically assess the role of competition on coral traits, multispecies studies in the wild are required. Here, we use 5 yr of data that includes 11 coral species on the reef crest at Lizard Island on the Great Barrier Reef to quantify the effect of competition on growth. Additionally, we test whether species differ in their susceptibility to direct‐contact (overgrowth and digestion) and overtopping competition, and whether species from some morphological groups are more likely to compete with one another than with species from other morphological groups. We also investigate the relationships between competitive ability and three key traits: growth rate, mechanical stability and fecundity. In contrast to most previous work using field manipulations of competition, we found a negligible effect of competition on growth. Acropora species consistently won overtopping encounters but lost in direct‐contact encounters, and these results were consistent among the four Acropora morphological groups. In contrast, the massive Goniastrea spp. were poor at overtopping but generally won direct‐contact encounters. Only tabular colonies were disproportionally more likely to compete against one another than with other morphologies. This propensity increases intraspecific relative to interspecific competition, a phenomenon that can promote coexistence when it is present among dominant competitors. Good competitors grew more quickly and had higher fecundity but were less mechanically stable, implying a tradeoff between performance during disturbance vs. performance in the absence of disturbance. We conclude that competition among adults is less likely to influence community dynamics than previously thought. If competition does have an effect, it is more likely to occur at life‐stages other than adults.
New Insight into the EC’ Mechanism of Uric Acid Regeneration in the Presence of Ascorbic Acid on a Poly(3,4‐ethylenedioxithiophene) Modified Gold Electrode
Authors: Crosnier de Lassichere Cédric , Latapie Laure , Evrard David , Gros Pierre
Published: March 2018

A gold electrode surface was functionalized by means of an electropolymerized conductive poly(3,4‐ethylenedioxythiophene) (PEDOT) organic layer. This modified electrode was used for the electrochemical detection of ascorbic (AA) and uric (UA) acids in an aqueous mixture with a selectivity around 340 mV. The electrochemical reactions kinetics were limited by AA diffusion and UA adsorption at the electrode surface, respectively. Following a previous study ([Electrochem Comm. 2011, 13, 423–425]) cyclic voltammetry was used to provide a better understanding of the EC’ mechanism of regeneration of UA by AA. Experiments particularly showed that allantoin (i. e. the final product of UA oxidation) is not actually involved in the synergic mechanism but rather the oxidized UA product diimine which is adsorbed at the electrode surface.
Tandem HILIC‐RP liquid chromatography for increased polarity coverage in food analysis
Authors: Hemmler Daniel , Heinzmann Silke S. , Wöhr Katrin , Schmitt‐Kopplin Philippe , Witting Michael
Published: March 2018

Comprehensive non‐targeted analysis of food products normally requires two complementary chromatographic runs to achieve maximum compound coverage. In this study, we present a sensitive tandem‐LC method, which combines RP and HILIC separation in a single run. The setup consists of a C18 trap column and two subsequently coupled analytical columns (HILIC and C18) which are operated in parallel. First, hydrophobic compounds are retained on the RP trap column while rather hydrophilic compounds are directly transferred onto a HILIC phase. Next, the pre‐fractionated sample composition is analyzed by HILIC or RP chromatography, respectively. The presented setup allows individual and independent gradient elution as well as interfacing with mass spectrometry. The performance of the method has been proven by means of food relevant standards and analysis of complex food samples (e.g. red wine, meat extract). The simple and robust setup provides high flexibility in the selection of column combinations and does not require sophisticated instrumental setups or software. The method significantly increases the covered polarity range compared to classical one‐dimensional chromatography. Our results indicate that tandem LC is a valuable and universal tool in the non‐targeted screening of various types of complex food samples.
Anti/genotoxic, longevity inductive, cytotoxic, and clastogenic‐related bioactivities of tomato and lycopene
Authors: Fernández‐Bedmar Zahira , Anter Jaouad , Alonso Moraga Ángeles
Published: March 2018

The aim of this study was to evaluate some biological activities of tomato as well as lycopene and to consider a new nutraceutic value for this fruit regarding to the protection against genetic damage and as a chemopreventive agent. Genotoxicity, DNA‐protection against hydrogen peroxide, and lifespan properties of tomato and lycopene were assessed through wing spot test and longevity assay using the Drosophila in vivo model. Additionally, chemopreventive activity was investigated through cytotoxicity, DNA‐fragmentation comet and annexin V FITC/PI assays using HL60 in vitro model. Results showed that: (i) tomato and lycopene are not genotoxic and protect against H2O2‐induced damage; (ii) with respect to the lifespan, tomato and lycopene are harmless at the lowest concentration; (iii) tomato is cytotoxic in a dose‐dependent manner, but not lycopene; (iv) tomato and lycopene do not induce internucleosomal DNA‐fragmentation although they induce significant clastogenic activity at low level in the leukemia cells. To sum up, tomato is a good candidate to be considered as a nutraceutical substance. Furthermore, synergistic action among other components within tomato matrix could be the cause of the health effects observed in this vegetable, which are not fully explained by lycopene. Environ. Mol. Mutagen. 59:427–437, 2018. © 2018 Wiley Periodicals, Inc.
Epilepsy as a dynamic disease: A Bayesian model for differentiating seizure risk from natural variability
Authors: Chiang Sharon , Vannucci Marina , Goldenholz Daniel M. , Moss Robert , Stern John M.
Published: March 2018

Objective

A fundamental challenge in treating epilepsy is that changes in observed seizure frequencies do not necessarily reflect changes in underlying seizure risk. Rather, changes in seizure frequency may occur due to probabilistic variation around an underlying seizure risk state caused by normal fluctuations from natural history, leading to seizure unpredictability and potentially suboptimal medication adjustments in epilepsy management. However, no rigorous statistical approach exists to systematically distinguish expected changes in seizure frequency due to natural variability from changes in underlying seizure risk.

Methods

Using data from SeizureTracker.com, a patient‐reported seizure diary tool containing over 1.2 million recorded seizures across 8 years, a novel epilepsy seizure risk assessment tool (EpiSAT) employing a Bayesian mixed‐effects hidden Markov model for zero‐inflated count data was developed to estimate changes in underlying seizure risk using patient‐reported seizure diary and clinical measurement data. Accuracy for correctly assessing underlying seizure risk was evaluated through a simulation comparison. Implications for the natural history of tuberous sclerosis complex (TSC) were assessed using data from SeizureTracker.com.

Results

EpiSAT led to significant improvement in seizure risk assessment compared to traditional approaches relying solely on observed seizure frequencies. Applied to TSC, four underlying seizure risk states were identified. The expected duration of each state was <12 months, providing a data‐driven estimate of the amount of time a person with TSC would be expected to remain at the same seizure risk level according to the natural course of epilepsy.

Significance

We propose a novel Bayesian statistical approach for evaluating seizure risk on an individual patient level using patient‐reported seizure diaries, which allows for the incorporation of external clinical variables to assess impact on seizure risk. This tool may improve the ability to distinguish true changes in seizure risk from natural variations in seizure frequency in clinical practice. Incorporation of systematic statistical approaches into antiepileptic drug (AED) management may help improve understanding of seizure unpredictability as well as timing of treatment interventions for people with epilepsy.
Jamestown Canyon encephalitis with NORSE and electrographic response to ribavirin: a case report
Authors: Savard Martin , Paradis Alain , Francoeur Charles L.
Published: March 2018

New‐onset refractory status epilepticus (NORSE) is a rare condition where refractory seizures occur with no obvious cause in an otherwise healthy individual. We report here the first case of a patient with NORSE caused by Jamestown Canyon virus, an emerging virus throughout North America. This is the first patient with Jamestown Canyon virus encephalitis treated by a specific antiviral agent, in this case intravenous ribavirin, with electroencephalography (EEG) evidence of improvement. This is finally the first reported death caused by this virus, here secondary to intensive care unit complications. Therefore, Jamestown Canyon virus should be considered as a NORSE etiology, and ribavirin may be an effective treatment of that condition, especially if used early.
Seismic characterization of hyperconcentrated flows in a volcanic environment
Authors: Coviello Velio , Capra Lucia , Vázquez Rosario , Márquez-Ramírez Victor H.
Published: March 2018

We present direct observations and monitoring data of a hyperconcentrated flow that occurred along La Lumbre ravine, one of the most active channels of Volcán de Colima in Mexico. Flow properties were inferred from video images and seismic data recorded by a geophone installed outside the channel. We collected flow samples 400 m upstream from the monitoring station and analyzed the variation of sediment concentration and grain‐size distribution over time. A joint analysis of hydrological (i.e. flow velocity, wetted perimeter) and rheological (i.e. yield stress τy and dynamic viscosity μm) parameters was performed to characterize the flow. Different flow regimes and sediment transport processes were identified and analyzed in comparison with both the amplitude and spectral features of the seismic signal. We observed differing sediment concentrations at the same discharge, suggesting a decoupling between sediment transport processes and discharge for low‐magnitude flows. A straightforward correlation was found between the amplitude of the seismic signal and the sediment concentration, and a value of 1.8 × 10−3 mm/s was identified that can be used as a threshold to recognize the hyperconcentrated phase of the flow. This information was tested on the complete seismic dataset gathered at La Lumbre ravine during the 2015 rainy season. We identified the transition from streamflow to hyperconcentrated flow (and/or vice versa) in 16 low‐magnitude events and we validated this result using the video recordings. The correlation between seismic amplitude and sediment concentration is valid at La Lumbre ravine but would need to be tested in other locations for the development of automatic flow classification methods. This work contributes to standardized seismic methods for characterizing flow processes in volcanic environments, also for the development of lahar early warning systems. Copyright © 2018 John Wiley & Sons, Ltd.
Impacts of headcut height on flow energy, sediment yield and surface landform during bank gully erosion processes in the Yuanmou Dry‐hot Valley region, southwest China
Authors: Zhang Baojun , Xiong Donghong , Zhang Guanghui , Zhang Su , Wu Han , Yang Dan , Xiao Liang , Dong Yifan , Su Zhengan , Lu Xiaoning
Published: March 2018

To quantify the changes in flow energy, sediment yield and surface landform impacted by headcut height during bank gully erosion, five experimental platforms were constructed with different headcut heights ranging from 25 to 125 cm within an in situ active bank gully head. A series of scouring experiments were conducted under concentrated flow and the changes in flow energy, sediment yield and surface landform were observed. The results showed that great energy consumption occurred at gully head compared to the upstream area and gully bed. The flow energy consumption at gully heads and their contribution rates increased significantly with headcut height. Gully headcuts also contributed more sediment yield than the upstream area. The mean sediment concentrations at the outlet of plots were 2.3 to 7.3 times greater than those at the end of upstream area. Soil loss volume at gully heads and their contribution rates also increased with headcut height significantly. Furthermore, as headcut height increased, the retreat distance of gully heads increased, which was 1.7 to 8.9 times and 1.1 to 3.2 times greater than the incision depth of upstream area and gully beds. Positive correlations were found between energy consumption and soil loss, indicating that energy consumption could be used to estimate soil loss of headcut erosion. Headcut height had a significant impact on flow energy consumption, and thus influenced the changes in sediment yield and landform during the process of gully headcut erosion. Headcut height was one of the important factors for gully erosion control in this region. Further studies are needed to identify the role of headcut height under a wide condition. Copyright © 2018 John Wiley & Sons, Ltd.
Bacteria‐sediment associations in an alpine, freshwater environment and their effects on particle size, density and settling velocity
Authors: Barrett David C. , Hodder Kyle R.
Published: March 2018

This study measures the presence of bacteria‐sediment associations (BSAs) in an alpine, glacier‐fed watershed in the Southern Coast Mountains of British Columbia, Canada. The impact of BSAs on the creation of flocculated particles and their settling velocity are quantified using a laser transmissometer. Results from the study indicate that BSAs are present in the watershed and vary over both space and time. The percentage of bacteria associated with sediment particles was found to range from < 1% to 40%. Major sources of planktonic bacteria such as agricultural land and wastewater treatment outflow co‐occur with large decreases in the BSA ratio. Laboratory analysis demonstrates that an increase in the concentration of bacteria was associated with a decrease in the volume concentration of small particles, and a decrease in both estimated density and measured settling velocity for particles in larger size classes; consistent with flocculated particles of increasing complexity arising from combinations of primary particles and/or BSAs. Paleoenvironmental reconstructions using laminated lake sediments in alpine, glacier‐fed systems benefit from a fuller understanding of the geomorphologic processes by which they formed. While bacteria are noted to enhance formation of flocculated particles in laboratory systems, their impact upon geomorphic processes in natural systems have yet to be fully explored. © 2018 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.
Effect of chitosan edible coating with Laurus nobilis extract on shelf life of cashew
Authors: Azimzadeh Behnaz , Jahadi Mahshid
Published: March 2018

This study tested the effects of the application of Laurus nobilis aqueous extract and edible coating of chitosan had on the chemical, microbial, and sensory attributes of cashew's shelf life. An aqueous extract of L. nobilis leaf (0, 0.5, and 1% w/w) was added to chitosan solution (0, 0.5, 1% w/w) in the cashew's coating. Cashews were dipped into the coating solution and were kept in polyethylene terephthalate containers. The result showed that chitosan and aqueous extract of L. nobilis coating had significant effects on peroxide and thiobarbituric acid value (p < .05). There was significant reduction in the growth of mold/yeast and mesophilic bacteria with higher concentration of chitosan and L. nobilis aqueous extract (p < .05). The results of this study show chitosan aqueous extract of L. nobilis coating could be an effective preservative method for extending shelf life and improving the stability of cashew.
Human papillomavirus type specific risk of progression and remission during long‐term follow‐up of equivocal and low‐grade HPV‐positive cervical smears
Authors: Vintermyr Olav Karsten , Andersland Marie Songstad , Bjørge Tone , Skar Robert , Iversen Ole Erik , Nygård Mari , Haugland Hans Kristian
Published: March 2018

The prevalence of clinically relevant HPV types and their specific risk for progression and regression in women with atypical squamous cells of uncertain significance (ASCUS) and low‐grade squamous intraepithelial lesions (LSIL) were studied in a routine screening population. A 4‐year cohort of women (n = 820) with ASCUS/LSIL and a positive HPV test in triage were followed for 6–9 years. The progression risks for CIN2+/CIN3+ were determined for single (71.2%) and multiple HPV infections (28.8%). The CIN2+ progression risk for all HPV 16, all HPV 35, single HPV 16 and single HPV 35 infections were 65.3% (95% CI: 59.6–71.0), 64.4% (95% CI: 50.4–78.4), 63.8% (95% CI: 56.2–71.4) and 73.7% (95% CI: 53.9–93.5), respectively. Based on CIN2+ progression risks four main groups were defined; the HPV 16 group, the HPV 31/33/35 group, the HPV 18/45/51/52 group and the HPV 39/56/58/59/66/68 group with progression risks of 65.3% (95% CI: 59.6–71.0), 62.1% (95% CI: 54.8–69.4), 52.6 (95% CI: 45.9–59.3) and 39.5 (95% CI: 33.0–46.0), respectively. In multivariate analyses, women in the age group 40–49 years had an increased risk of CIN2+ progression. As for CIN3+, HPV 16 had a higher progression risk than other HPV risk groups (p < 0.05). In multiple infections only HPV 16 had a significant additive CIN3+ progression risk (p < 0.05) as compared to other HPV risk groups. In summary, HPV types 16 and 35, including the HPV risk group 31/33/35, had a similar CIN2+ progression risk, but only HPV 16 had a higher risk for CIN3+ progression.
The effect of FASN inhibition on the growth and metabolism of a cisplatin‐resistant ovarian carcinoma model
Authors: Papaevangelou Efthymia , Almeida Gilberto S. , Box Carol , deSouza Nandita M. , Chung Yuen‐Li
Published: March 2018

Overexpression of fatty acid synthase (FASN), a key regulator of the de novo synthesis of fatty acids, has been demonstrated in a variety of cancers and is associated with poor prognosis and increased multidrug resistance. Inhibition of FASN with the anti‐obesity drug orlistat has been shown to have significant anti‐tumourigenic effects in many cancers, notably breast and prostate. In our study, we investigated whether FASN inhibition using orlistat is an effective adjunctive treatment for ovarian cancers that have become platinum resistant using a cisplatin‐resistant ovarian tumour xenograft model in mice. Mice were treated with orlistat or cisplatin or a combination and metabolite analysis and histopathology were performed on the tumours ex vivo. Orlistat decreased tumour fatty acid metabolism by inhibiting FASN, cisplatin reduced fatty acid β‐oxidation, and combination treatment delayed tumour growth and induced apoptotic and necrotic cell death in cisplatin‐resistant ovarian cancer cells over and above that with either treatment alone. Combination treatment also decreased glutamine metabolism, nucleotide and glutathione biosynthesis and fatty acid β‐oxidation. Our data suggest that orlistat chemosensitised platinum‐resistant ovarian cancer to treatment with platinum and resulted in enhanced efficacy.
Multi‐regional sequencing reveals intratumor heterogeneity and positive selection of somatic mtDNA mutations in hepatocellular carcinoma and colorectal cancer
Authors: Li Xin , Guo Xu , Li Deyang , Du Xiaohong , Yin Chun , Chen Cheng , Fang Wan , Bian Zhenyuan , Zhang Jing , Li Bingshan , Yang Hushan , Xing Jinliang
Published: March 2018

Recent studies have revealed significant intratumor heterogeneity (ITH) of nuclear genome mutations and highlighted its function in tumor progression and treatment resistance. However, the ITH of somatic mitochondrial DNA (mtDNA) mutations detected in cancers remains unknown. In this study, we performed multiregional mtDNA sequencing of tumor and paratumor tissue samples from 12 hepatocellular carcinoma (HCC) and 13 colorectal cancer (CRC) patients. A substantial level of mtDNA mutations was found in paired non‐HCC inflammatory tissues, suggesting that these tissues might not be mtDNA‐genetically “normal.” Moreover, our data indicated that the ITH of somatic mtDNA mutations was a common feature in HCC and CRC patients. In addition, we found that shared mutations which were observed in at least 2 samples in each patient exhibited a significantly higher heteroplasmic level than mutations that were private to a specific tumor region from both HCC (p = 0.039) and CRC patients (p = 0.001). The heteroplasmic level of shared mutations was positively correlated with intratumoral recurrence of mtDNA mutations. We also found that shared mutations in tumor tissues with a higher degree of pathogenicity risk exhibited a higher heteroplasmic level and intratumoral recurrence in both HCC and CRC patients. These findings suggest that some mtDNA mutations may undergo positive selection during the clonal expansion. Taken together, our analyses identified various levels of ITH of somatic mtDNA mutations in HCC and CRC patients and provided evidence supporting the positive selection working on some somatic mtDNA mutations in tumor tissues.
Maternal and perinatal outcomes in pregnant women with suspected Ebola virus disease in Sierra Leone, 2014
Authors: Lyman Meghan , Mpofu Jonetta Johnson , Soud Fatma , Oduyebo Titilope , Ellington Sascha , Schlough Gabriel W. , Koroma Alimamy P. , McFadden Jevon , Morof Diane
Published: March 2018

Objective

To describe maternal and perinatal outcomes among pregnant women with suspected Ebola virus disease (EVD) in Sierra Leone.

Methods

Observational investigation of maternal and perinatal outcomes among pregnant women with suspected EVD from five districts in Sierra Leone from June to December 2014. Suspected cases were ill pregnant women with symptoms suggestive of EVD or relevant exposures who were tested for EVD. Case frequencies and odds ratios were calculated to compare patient characteristics and outcomes by EVD status.

Results

There were 192 suspected cases: 67 (34.9%) EVD‐positive, 118 (61.5%) EVD‐negative, and 7 (3.6%) EVD status unknown. Women with EVD had increased odds of death (OR 10.22; 95% CI, 4.87–21.46) and spontaneous abortion (OR 4.93; 95% CI, 1.79–13.55) compared with those without EVD. Women without EVD had a high frequency of death (30.2%) and stillbirths (65.9%). One of 14 neonates born following EVD‐negative and five of six neonates born following EVD‐positive pregnancies died.

Conclusion

EVD‐positive and EVD‐negative women with suspected EVD had poor outcomes, highlighting the need for increased attention and resources focused on maternal and perinatal health during an urgent public health response. Capturing pregnancy status in nationwide surveillance of EVD can help improve understanding of disease burden and design effective interventions.
Label‐free ultra‐sensitive visualization of structure below the diffraction resolution limit
Authors: Alexandrov Sergey , McGrath James , Sheppard Colin J. R. , Boccafoschi Francesca , Giannini Cinzia , Sibillano Teresa , Subhash Hrebesh , Hogan Josh , Leahy Martin
Published: March 2018

For both fundamental study of biological processes and early diagnosis of diseases, information about nanoscale changes in tissue and cell structure is crucial. Nowadays, almost all currently known nanoscopy methods rely upon the contrast created by fluorescent stains attached to the object or molecule of interest. This causes limitations due to the impact of the label on the object and its environment, as well as its applicability in vivo, particularly in humans. In this paper, a new label‐free approach to visualize small structure with nano‐sensitivity to structural alterations is introduced. Numerically synthesized profiles of the axial spatial frequencies are used to probe the structure within areas whose size can be beyond the diffraction resolution limit. Thereafter, nanoscale structural alterations within such areas can be visualized and objects, including biological ones, can be investigated with sub‐wavelength resolution, in vivo, in their natural environment. Some preliminary results, including numerical simulations and experiments, which demonstrate the nano‐sensitivity and super‐resolution ability of our approach, are presented.
The kinetics and mechanism of bone morphogenetic protein 2 release from calcium phosphate‐based implant‐coatings
Authors: Liu Yuelian , Schouten Corinne , Boerman Otto , Wu Gang , Jansen John A. , Hunziker Ernst B.
Published: March 2018

Biomimetically deposited calcium phosphate‐based coatings of prostheses can serve as a vehicle for the targeted delivery of growth factors to the local implant environment. Based on indirect evidence in previous studies we hypothesize that such agents are liberated gradually from the coating via a cell‐mediated degradation. In the present study, we tested this hypothesis by investigating the release mechanism and its kinetics by use of a radiolabeled osteogenic agent (131I‐BMP‐2) under conditions in which native cell populations with a coating‐degradative potential were either absent or present. The release of 131I‐BMP‐2 was monitored for 5 weeks, either in vitro or after implantation at an ectopic (subcutaneous) site in rats in vivo. Only from implants that bore a coating‐incorporated depot of bone morphogenetic protein 2 (BMP‐2) was the agent released slowly and steadily over 5 weeks, that is, 50% of the loaded dose was liberated in vivo (5 to 10% weekly), as against 14.6% in vitro (less than 1% weekly). The coatings bearing an incorporated depot of BMP‐2 underwent significant cell‐mediated degradation, whereas under cell‐free conditions no degradation occurred, and the spontaneous release of BMP‐2 was negligible. Our findings confirm this carrier system to be a suitable vehicle for the sustained and cell‐mediated delivery of BMP‐2. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2363–2371, 2018.
Periodic microstructures on bioactive glass surfaces enhance osteogenic differentiation of human mesenchymal stromal cells and promote osteoclastogenesis in vitro
Authors: Höner Miriam , Lauria Ines , Dabhi Christina , Kant Sebastian , Leube Rudolf E. , Fischer Horst
Published: March 2018

Bioactive glasses (BG) are known for their ability to bond to hard and soft tissues. We hypothesized that the stimulation of bone remodeling, including cellular bone forming and bone resorbing processes, can be increased by applying periodic microstructures on the glass surfaces in vitro. To test our hypothesis, two different BG (45S5 and 13‐93) were microstructured in a groove‐and‐ridge pattern of different sizes by a novel casting process and tested in cell culture experiments using human mesenchymal stromal cells (hMSCs) and RAW 264.7 cells. The microstructures induced contact guidance of hMSCs and increased osteogenic marker gene expression of the stem cells, compared to non‐structured glass surfaces as verified by ELISA and quantitative real‐time PCR (qPCR) analyses. Furthermore, the structures stimulated the differentiation of RAW cells to osteoclast‐like cells confirmed by TRAP gene expression and their resorption activity causing visible resorption lacunae. Our results demonstrate that periodically microstructured BG (especially 45S5) might improve the osteogenic differentiation of hMSCs and influence the activity of material resorbing cells in vitro. Hence, microstructuring of BG could enhance the remodeling process of bone substitutes critical for the formation of new bone tissue in vivo and thus be used to trigger bone remodeling kinetics in vivo. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1965–1978, 2018.
Exploring the anti‐quorum sensing activity of a d‐limonene nanoemulsion for Escherichia coli O157:H7
Authors: Wang Renjie , Vega Pablo , Xu Yi , Chen Chin‐Yi , Irudayaraj Joseph
Published: March 2018

In this study, a d‐limonene nanoemulsion was developed by using a spontaneous emulsification method and its potential to inhibit the quorum sensing (QS)‐regulated properties of Escherichia coli O157:H7 (E. coli) were revealed. The results in this study showed that d‐limonene nanoemulsion inhibited E. coli biofilm formation through the suppression of curli and extracellular polymeric substance (EPS) production without inhibiting cell growth, and decreased swimming and swarming ability. Further analyses showed that d‐limonene nanoemulsion interfered with auto‐inducer 2 (AI‐2) communication and repressed the expression of curli related genes and AI‐2 importer genes in E. coli. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1979–1986, 2018.
Layer‐by‐layer buildup of polysaccharide‐containing films: Physico‐chemical properties and mesenchymal stem cells adhesion
Authors: Kulikouskaya Viktoryia I. , Pinchuk Sergei V. , Hileuskaya Kseniya S. , Kraskouski Aliaksandr N. , Vasilevich Irina B. , Matievski Kirill A. , Agabekov Vladimir E. , Volotovski Igor D.
Published: March 2018

Layer‐by‐Layer assembled polyelectrolyte films offer the opportunity to control cell attachment and behavior on solid surfaces. In the present study, multilayer films based on negatively charged biopolymers (pectin, dextran sulfate, carboxymethylcellulose) and positively charged polysaccharide chitosan or synthetic polyelectrolyte polyethyleneimine has been prepared and evaluated. Physico‐chemical properties of the formed multilayer films, including their growth, morphology, wettability, stability, and mechanical properties, have been studied. We demonstrated that chitosan‐containing films are characterized by the linear growth, the defect‐free surface, and predominantly viscoelastic properties. When chitosan is substituted for the polyethyleneimine in the multilayer system, the properties of the formed films are significantly altered: the rigidity and surface roughness increases, the film growth acquires the exponential character. The multilayer films were subsequently used for culturing mesenchymal stem cells. It has been determined that stem cells effectively adhered to chitosan‐containing films and formed on them the monolayer culture of fibroblast‐like cells with high viability. Our results show that cell attachment is a complex process which is not only governed by the surface functionality because one of the key parameter effects on cell adhesion is the stiffness of polyelectrolyte multilayer films. We therefore propose our Layer‐by‐Layer films for applications in tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2093‐2104, 2018.
Vacuumed collagen‐impregnated bioglass scaffolds: Characterization and influence on proliferation and differentiation of bone marrow stromal cells
Authors: Kido Hueliton Wilian , Gabbai‐Armelin Paulo Roberto , Avanzi Ingrid Regina , da Silva Antonio Carlos , Fernandes Kelly Rossetti , Fortulan Carlos Alberto , Rennó Ana Claudia Muniz
Published: March 2018

This study evaluated physical–chemical characteristics of a vacuumed collagen‐impregnated bioglass (BG) scaffolds and bone marrow stromal cells (BMSCs) behavior on those composites. scanning electron microscope and energy dispersive x‐ray spectroscope demonstrated collagen (Col) was successfully introduced into BG. Vacuum impregnation system has showed efficiency for Col impregnation in BG scaffolds (approximately 20 wt %). Furthermore, mass weight decreasing and more stabilized pH were observed over time for BG/Col upon incubation in phosphate buffered saline compared to plain BG under same conditions. Calcium evaluation (Ca assay) demonstrated higher calcium uptake for BG/Col samples compared to BG. In addition, BG samples presented hydroxyapatite crystals formation on its surface after 14 days in simulated body fluid solution, and signs of initial degradation were observed for BG and BG/Col after 21 days. Fourier transform infrared spectroscopy spectra for both groups indicated peaks for hydroxyapatite formation. Finally, a significant increase of BMSCs viability for both composites was observed compared to control group, but no increase of osteogenic differentiation‐related gene expressions were found. In summary, BG/Col scaffolds have improved degradation, pH equilibrium and Ca mineralization over time, accompanied by hydroxyapatite formation. Moreover, both BG and BG/Col scaffolds were biocompatible and noncytotoxic, promoting a higher cell viability compared to control. Future investigations should focus on additional molecular and in vivo studies in order to evaluate biomaterial performance for bone tissue engineering applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 211–222, 2019.
Exploitation of cold‐active cephalosporin C acylase by computer‐aided directed evolution and its potential application in low‐temperature biosynthesis of 7‐aminocephalosporanic acid
Authors: Tang Cun‐Duo , Shi Hong‐Ling , Jiao Zhu‐Jin , Shi Hong‐Fei , Yao Lun‐Guang , Xu Jian‐He , Kan Yun‐Chao
Published: March 2018

BACKGROUND

Cephalosporin C acylase (CA) plays a key role in the one‐step enzymatic catalysis of 7‐aminocephalosporanic acid (7‐ACA) from Cephalosporin C (CPC). However, the synthesis of 7‐ACA needs low‐temperature conditions: unless catalyzed at 13 °C, it will produce large amounts of undesired products. Unfortunately, cephalosporin CA catalyzes CPC to 7‐ACA directly at a very low efficiency at 13 °C or below.

RESULTS

In this work, multiple techniques including molecular docking, multi‐site random‐directed mutagenesis and high‐throughput screening were adopted and combined into an engineering strategy to improve the cold adaptability of CA. Thus, the best‐hit mutant 9H9 containing mutations of P238G, P449G and P582G was screened revealing a specific activity of 1.94 U mg−1 at 13 °C, which is 1.3‐fold higher than that of the parent. Compared with the parent, the mutant 9H9 shows a slight decline in the Km value and significant improvement in the Vmax value. In addition, the yield of 7‐ACA catalyzed by 9H9 was obviously higher than that of the parent at low temperature.

CONCLUSION

A new and viable strategy was established for improving the cold adaptability of CA and investigations were made into enhancing its conformational flexibility. This might lay a solid foundation for future study and industrial application of CAs. © 2018 Society of Chemical Industry
Development of Mimokines, chemokine N terminus-based CXCR4 inhibitors optimized by phage display and rational design
Authors: Fievez Virginie , Szpakowska Martyna , Mosbah Amor , Arumugam Karthik , Mathu Julie , Counson Manuel , Beaupain Nadia , Seguin-Devaux Carole , Deroo Sabrina , Baudy-Floc’h Michèle , Chevigné Andy
Published: March 2018

The chemokine receptor CXCR4 (C-X-C chemokine receptor type 4 also known as fusin or CD184 (cluster of differentiation 184)) is implicated in various biological and pathological processes of the hematopoietic and immune systems. CXCR4 is also one of the major coreceptors for HIV-1 entry into target cells and is overexpressed in many cancers, supporting cell survival, proliferation, and migration. CXCR4 is thus an extremely relevant drug target. Among the different strategies to block CXCR4, chemokine-derived peptide inhibitors hold great therapeutic potential. In this study, we used the N-terminus of vCCL2/vMIPII, a viral CXCR4 antagonist chemokine, as a scaffold motif to engineer and select CXCR4 peptide inhibitors, called Mimokines, which imitate the chemokine-binding mode but display an enhanced receptor affinity, antiviral properties, and receptor selectivity. We first engineered a Mimokine phage displayed library based on the first 21 residues of vCCL2, in which cysteine 11 and 12 were fully randomized and screened it against purified CXCR4 stabilized in liposomes. We identified Mimokines displaying up to 4-fold higher affinity for CXCR4 when compared to the reference peptide and fully protected MT-4 cells against HIV-1 infection. These selected Mimokines were then subjected to dimerization, D-amino acid, and aza-β3-amino acid substitution to further enhance their potency and selectivity. Optimized Mimokines exhibited up to 120-fold enhanced CXCR4 binding (range of 20 nM) and more than 200-fold improved antiviral properties (≤ 1 μM) compared to the parental Mimokines. Interestingly, these optimized Mimokines also showed up to 25-fold weaker affinity for ACKR3/CXCR7 and may therefore serve as lead compounds for further development of more selective CXCR4 peptide inhibitors and probes.

Development of CXCR4 peptide inhibitors with enhanced receptor affinity/selectivity and antiviral properties.
Repeatability, reproducibility, and accuracy of quantitative mri of the breast in the community radiology setting
Authors: Sorace Anna G. , Wu Chengyue , Barnes Stephanie L. , Jarrett Angela M. , Avery Sarah , Patt Debra , Goodgame Boone , Luci Jeffery J. , Kang Hakmook , Abramson Richard G. , Yankeelov Thomas E. , Virostko John
Published: March 2018

Background

Quantitative diffusion‐weighted MRI (DW‐MRI) and dynamic contrast‐enhanced MRI (DCE‐MRI) have the potential to impact patient care by providing noninvasive biological information in breast cancer.

Purpose/Hypothesis

To quantify the repeatability, reproducibility, and accuracy of apparent diffusion coefficient (ADC) and T1‐mapping of the breast in community radiology practices.

Study Type

Prospective.

Subjects/Phantom

Ice‐water DW‐MRI and T1 gel phantoms were used to assess accuracy. Normal subjects (n = 3) and phantoms across three sites (one academic, two community) were used to assess reproducibility. Test–retest analysis at one site in normal subjects (n = 12) was used to assess repeatability.

Field Strength/Sequence

3T Siemens Skyra MRI quantitative DW‐MRI and T1‐mapping.

Assessment

Quantitative DW‐MRI and T1‐mapping parametric maps of phantoms and fibroglandular and adipose tissue of the breast.

Statistical Tests

Average values of breast tissue were quantified and Bland–Altman analysis was performed to assess the repeatability of the MRI techniques, while the Friedman test assessed reproducibility.

Results

ADC measurements were reproducible across sites, with an average difference of 1.6% in an ice‐water phantom and 7.0% in breast fibroglandular tissue. T1 measurements in gel phantoms had an average difference of 2.8% across three sites, whereas breast fibroglandular and adipose tissue had 8.4% and 7.5% average differences, respectively. In the repeatability study, we found no bias between first and second scanning sessions (P = 0.1). The difference between repeated measurements was independent of the mean for each MRI metric (P = 0.156, P = 0.862, P = 0.197 for ADC, T1 of fibroglandular tissue, and T1 of adipose tissue, respectively).

Data Conclusion

Community radiology practices can perform repeatable, reproducible, and accurate quantitative T1‐mapping and DW‐MRI. This has the potential to dramatically expand the number of sites that can participate in multisite clinical trials and increase clinical translation of quantitative MRI techniques for cancer response assessment.

Level of Evidence: 1

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2018;48:695–707.
Dynamic effects of personal initiative on engagement and exhaustion: The role of mood, autonomy, and support
Authors: Zacher Hannes , Schmitt Antje , Jimmieson Nerina L. , Rudolph Cort W.
Published: March 2018

Researchers have neglected dynamic effects of proactive behavior on occupational well‐being. We investigated effects of change in personal initiative over 6 months on changes in emotional engagement and exhaustion over the following 6 months. On the basis of the control‐process theory on affect, we hypothesized that changes in positive and negative moods mediate these effects conditional upon employees' level of perceived organizational support. On the basis of action regulation theory, we assumed that change in job autonomy also acts as a mediator. Data came from 297 employees who responded to 3 surveys separated by 6‐month intervals. Results of latent change score modeling showed that change in personal initiative negatively predicted change in positive mood and, when perceived organizational support was low, positively predicted change in negative mood. In addition, change in personal initiative positively predicted change in job autonomy. Change in personal initiative had negative indirect effects on change in emotional engagement, and positive indirect effects on change in emotional exhaustion through changes in positive and negative moods (but not through change in job autonomy). A reverse causal model did not yield significant indirect effects. Overall, these findings suggest that an increase in proactive behavior can have detrimental effects on occupational well‐being.
An intercomparison of a large ensemble of statistical downscaling methods over Europe: Results from the VALUE perfect predictor cross‐validation experiment
Authors: Gutiérrez J. M. , Maraun D. , Widmann M. , Huth R. , Hertig E. , Benestad R. , Roessler O. , Wibig J. , Wilcke R. , Kotlarski S. , San Martín D. , Herrera S. , Bedia J. , Casanueva A. , Manzanas R. , Iturbide M. , Vrac M. , Dubrovsky M. , Ribalaygua J. , Pórtoles J. , Räty O. , Räisänen J. , Hingray B. , Raynaud D. , Casado M. J. , Ramos P. , Zerenner T. , Turco M. , Bosshard T. , Štěpánek P. , Bartholy J. , Pongracz R. , Keller D. E. , Fischer A. M. , Cardoso R. M. , Soares P. M. M. , Czernecki B. , Pagé C.
Published: March 2018

VALUE is an open European collaboration to intercompare downscaling approaches for climate change research, focusing on different validation aspects (marginal, temporal, extremes, spatial, process‐based, etc.). Here we describe the participating methods and first results from the first experiment, using “perfect” reanalysis (and reanalysis‐driven regional climate model (RCM)) predictors to assess the intrinsic performance of the methods for downscaling precipitation and temperatures over a set of 86 stations representative of the main climatic regions in Europe. This study constitutes the largest and most comprehensive to date intercomparison of statistical downscaling methods, covering the three common downscaling approaches (perfect prognosis, model output statistics—including bias correction—and weather generators) with a total of over 50 downscaling methods representative of the most common techniques.

Overall, most of the downscaling methods greatly improve (reanalysis or RCM) raw model biases and no approach or technique seems to be superior in general, because there is a large method‐to‐method variability. The main factors most influencing the results are the seasonal calibration of the methods (e.g., using a moving window) and their stochastic nature. The particular predictors used also play an important role in cases where the comparison was possible, both for the validation results and for the strength of the predictor–predictand link, indicating the local variability explained. However, the present study cannot give a conclusive assessment of the skill of the methods to simulate regional future climates, and further experiments will be soon performed in the framework of the EURO‐CORDEX initiative (where VALUE activities have merged and follow on).

Finally, research transparency and reproducibility has been a major concern and substantive steps have been taken. In particular, the necessary data to run the experiments are provided at http://www.value‐cost.eu/data and data and validation results are available from the VALUE validation portal for further investigation: http://www.value‐cost.eu/validationportal.
The impact of the resolution of meteorological data sets on catchment‐scale precipitation and drought studies
Authors: Hellwig Jost , Stahl Kerstin , Ziese Markus , Becker Andreas
Published: March 2018

Meteorological data provide the basis to study hydrology at a range of scales, including catchment‐scale drought propagation studies for early warning of hydrological drought impacts. Gridded meteorological data sets are readily available and used for this purpose. As these data sets differ in spatial/temporal coverage and spatial/temporal resolution, for most studies there is a trade‐off between these two aspects. While this trade‐off has mostly been described for precipitation sums, other characteristics will also matter. We therefore investigated biases in meteorological indices derived from low‐resolution input data at the scale of small catchments (smaller than 200 km2) distributed over Germany. A comparison among the data sets REGNIE (covering Germany, 1 × 1 km grid), E‐OBS (Europe, 0.25° grid) and GPCC (whole world, 1° grid) was carried out. Generally, for small catchments biases in precipitation increase with decreasing resolution because low‐resolution data sets are not able to resolve the relevant spatial variability with elevation. In addition, different interpolation methods lead to high differences in the number of dry days. Relative measures such as the correlation coefficient reveal good consistencies of dry and wet periods. Standardized precipitation index (SPI) values, which are often used to indicate drought, match well on average but show some variations. Overall, the results suggest that absolute values of low‐resolution data sets may not be suitable to use for an assessment of the hydrological conditions at the scale of small headwater catchments, whereas relative measures for determining periods of drought are more trustworthy. For large river basins the resolution of the data set is less relevant, but different interpolation methods still lead to different results for different products. Therefore, studies that directly use meteorological data for catchment‐scale applications should choose data at the appropriate scale and may need to consider adjustments of precipitation amounts with elevation and of the definition of dry days.