bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface plastic flow in polishing of rough surfaces
Authors: Iquebal Ashif S. , Sagapuram Dinakar , Bukkapatnam Satish T. S.
Published: July 2019

We present experimental evidence for a new mechanism for how smooth surfaces emerge during repetitive sliding contacts, as in polishing. Electron microscopy observations of Ti-6Al-4V surface with a spherical asperity structure—realized via additive manufacturing—during successive polishing stages suggest that asperity-abrasive contacts exhibit viscous behavior, where the asperity material flows in the form of thin (1–10 μm) fluid-like layers. Subsequent bridging of these layers among neighboring asperities results in progressive surface smoothening. Using analytical asperity-abrasive contact temperature modeling and microstructural characterization, we show that the sliding contacts encounter flash temperatures of the order of 700–900 K which is in the range of the dynamic recrystallization temperature of the material considered, thus supporting the experimental observations. Besides providing a new perspective on the long-held mechanism of polishing, our observations provide a novel approach based on graph theory to quantitatively characterize the evolution of surface morphology. Results suggest that the graph representation offers a more efficient measure to characterize the surface morphology emerging at various stages of polishing. The research findings and observations are of broad relevance to the understanding of plastic flow behavior of sliding contacts ubiquitous in materials processing, tribology, and natural geological processes as well as present unique opportunities to tailor the microstructures by controlling the thermomechanics of the asperity-abrasive contacts.
Molecular epidemiology of Klebsiella variicola obtained from different sources
Authors: Barrios-Camacho Humberto , Aguilar-Vera Alejandro , Beltran-Rojel Marilu , Aguilar-Vera Edgar , Duran-Bedolla Josefina , Rodriguez-Medina Nadia , Lozano-Aguirre Luis , Perez-Carrascal Olga Maria , Rojas Jesús , Garza-Ramos Ulises
Published: July 2019

Klebsiella variicola is considered an emerging pathogen in humans and has been described in different environments. K. variicola belongs to Klebsiella pneumoniae complex, which has expanded the taxonomic classification and hindered epidemiological and evolutionary studies. The present work describes the molecular epidemiology of K. variicola based on MultiLocus Sequence Typing (MLST) developed for this purpose. In total, 226 genomes obtained from public data bases and 28 isolates were evaluated, which were mainly obtained from humans, followed by plants, various animals, the environment and insects. A total 166 distinct sequence types (STs) were identified, with 39 STs comprising at least two isolates. The molecular epidemiology of K. variicola showed a global distribution for some STs was observed, and in some cases, isolates obtained from different sources belong to the same ST. Several examples of isolates corresponding to kingdom-crossing bacteria from plants to humans were identified, establishing this as a possible route of transmission. goeBURST analysis identified Clonal Complex 1 (CC1) as the clone with the greatest distribution. Whole-genome sequencing of K. variicola isolates revealed extended-spectrum β-lactamase- and carbapenemase-producing strains with an increase in pathogenicity. MLST of K. variicola is a strong molecular epidemiological tool that allows following the evolution of this bacterial species obtained from different environments.
Biochemical characterisation of fumarase C from a unicellular cyanobacterium demonstrating its substrate affinity, altered by an amino acid substitution
Authors: Katayama Noriaki , Takeya Masahiro , Osanai Takashi
Published: July 2019

The tricarboxylic acid cycle produces NADH for oxidative phosphorylation and fumarase [EC 4.2.1.2] is a critical enzyme in this cycle, catalysing the reversible conversion of fumarate and l-malate. Fumarase is applied to industrial l-malate production as a biocatalyst. l-malate is used in a wide range of industries such as food and beverage, pharmacy chemistry. Although the biochemical properties of fumarases have been studied in many organisms, they have not been investigated in cyanobacteria. In this study, the optimum pH and temperature of Synechocystis 6803 fumarase C (SyFumC) were 7.5 and 30 °C, respectively. The Km of SyFumC for l-malate was higher than for fumarate. Furthermore, SyFumC activity was strongly inhibited by citrate and succinate, consistent with fumarases in other organisms. Substitution of alanine by glutamate at position 314 of SyFumC changed the kcat for fumarate and l-malate. In addition, the inhibitory effects of citrate and succinate on SyFumC activity were alleviated. Phylogenetic analysis revealed cyanobacterial fumarase clades divided in non-nitrogen-fixing cyanobacteria and nitrogen-fixing cyanobacteria. SyFumC was thus biochemically characterised, including identification of an amino acid residue important for substrate affinity and enzymatic activity.
Comparative structural and evolutionary analyses predict functional sites in the artemisinin resistance malaria protein K13
Authors: Coppée Romain , Jeffares Daniel C. , Miteva Maria A. , Sabbagh Audrey , Clain Jérôme
Published: July 2019

Numerous mutations in the Plasmodium falciparum Kelch13 (K13) protein confer resistance to artemisinin derivatives, the current front-line antimalarial drugs. K13 is an essential protein that contains BTB and Kelch-repeat propeller (KREP) domains usually found in E3 ubiquitin ligase complexes that target substrate protein(s) for ubiquitin-dependent degradation. K13 is thought to bind substrate proteins, but its functional/interaction sites and the structural alterations associated with artemisinin resistance mutations remain unknown. Here, we screened for the most evolutionarily conserved sites in the protein structure of K13 as indicators of structural and/or functional constraints. We inferred structure-dependent substitution rates at each amino acid site of the highly conserved K13 protein during the evolution of Apicomplexa parasites. We found two solvent-exposed patches of extraordinarily conserved sites likely involved in protein-protein interactions, one in BTB and the other one in KREP. The conserved patch in K13 KREP overlaps with a shallow pocket that displays a differential electrostatic surface potential, relative to neighboring sites, and that is rich in serine and arginine residues. Comparative structural and evolutionary analyses revealed that these properties were also found in the functionally-validated shallow pocket of other KREPs including that of the cancer-related KEAP1 protein. Finally, molecular dynamics simulations carried out on PfK13 R539T and C580Y artemisinin resistance mutant structures revealed some local structural destabilization of KREP but not in its shallow pocket. These findings open new avenues of research on one of the most enigmatic malaria proteins with the utmost clinical importance.
Citrate anion improves chronic dialysis efficacy, reduces systemic inflammation and prevents Chemerin-mediated microvascular injury
Authors: Dellepiane Sergio , Medica Davide , Guarena Cesare , Musso Tiziana , Quercia Alessandro Domenico , Leonardi Gianluca , Marengo Marita , Migliori Massimiliano , Panichi Vincenzo , Biancone Luigi , Pizzarelli Francesco , Camussi Giovanni , Cantaluppi Vincenzo
Published: July 2019

Systemic inflammation and uremic toxins (UT) determine the increased cardiovascular mortality observed in chronic hemodialysis (HD) patients. Among UT, the adipokine Chemerin induces vascular dysfunction by targeting both endothelial and vascular smooth muscular cells (EC and VSMC). As Citrate anion modulates oxidative metabolism, systemic inflammation and vascular function, we evaluated whether citrate-buffered dialysis improves HD efficiency, inflammatory parameters and chemerin-mediated microvascular injury. 45 patients were treated in sequence with acetate, citrate and, again, acetate-buffered dialysis solution (3 months per interval). At study admission and after each treatment switch, we evaluated dialysis efficacy and circulating levels of chemerin and different inflammatory biomarkers. In vitro, we stimulated EC and VSMC with patients’ plasma and we investigated the role of chemerin as UT. Citrate dialysis increased HD efficacy and reduced plasma levels of CRP, fibrinogen, IL6 and chemerin. In vitro, patients’ plasma induced EC and VSMC dysfunction. These effects were reduced by citrate-buffered solutions and paralleled by the decrease of chemerin levels. Consistently, chemerin receptor knockdown reduced EC and VSMC dysfunction. In conclusion, Switching from acetate to citrate improved dialysis efficacy and inflammatory parameters; in vitro, chemerin-induced EC and VSMC injury were decreased by using citrate as dialysis buffer.
Inerolysin and vaginolysin, the cytolysins implicated in vaginal dysbiosis, differently impair molecular integrity of phospholipid membranes
Authors: Ragaliauskas Tadas , Plečkaitytė Milda , Jankunec Marija , Labanauskas Linas , Baranauskiene Lina , Valincius Gintaras
Published: July 2019

The pore-forming toxins, inerolysin (INY) and vaginolysin (VLY), produced by vaginal bacteria Lactobacillus iners and Gardnerella vaginalis were studied using the artificial cholesterol-rich tethered bilayer membranes (tBLMs) by electrochemical techniques. The electrochemical impedance spectroscopy (EIS) of tBLMs attested for the toxin-induced impairment of the integrity of phospholipid membranes. This observation was in line with the atomic force microscopy data demonstrating formation of oligomeric protein assemblies in tBLMs. These assemblies exhibited different morphologies: VLY mostly formed complete rings, whereas INY produced arciform structures. We found that both EIS (membrane damage) and the surface plasmon resonance (protein binding) data obtained on tBLMs are in-line with the data obtained in human cell lysis experiments. EIS, however, is capable of capturing effects inaccessible for biological activity assays. Specifically, we found that the INY-induced damage of tBLMs is nearly a linear function of membrane cholesterol content, whereas VLY triggered significant damage only at high (50 mol%) cholesterol concentrations. The observed differences of INY and VLY activities on phospholipid membranes might have clinical importance: both toxin-producing bacteria have been found in healthy vagina and dysbiosis, suggesting the need for adaptation at different vaginal conditions. Our results broaden the possibilities of application of tBLMs in medical diagnostics.
Consequence of insertion trauma – effect on early measurements when using intracerebral devices
Authors: Andelius Ted Carl Kejlberg , Pedersen Mette Vestergård , Bøgh Nikolaj , Omann Camilla , Hjortdal Vibeke Elisabeth , Pedersen Michael , Kyng Kasper Jacobsen , Henriksen Tine Brink
Published: July 2019

There are a variety of devices that quantify biological properties of cerebral tissue. Installing such device will cause a local insertion trauma, which will affect early measurements. Current literature proposes minimum one hour of observation before acquiring first measurements when using microdialysis. It is unknown whether this applies to other intracerebral devices. We therefore aimed to investigate time needed to reach steady state when using microdialysis and two intracerebral probes in a piglet model. Ten newborn piglets less than 24 hours of age were anaesthetized. Two probes (Codman and OxyLite/OxyFlo) and a microdialysis catheter (CMA Microdialysis) were installed 10 mm into the left hemisphere. Probes measured intracranial pressure, cerebral blood flow, and oxygen tension. The microdialysis catheter measured lactate, glucose, glycerol, and pyruvate. Measurements were acquired hourly for 20 hours. Lactate and glycerol peaked immediately after insertion and reached steady state after approximately four hours. Glucose, pyruvate, cerebral blood flow, and intracranial pressure reached steady state immediately. Oxygen tension reached steady state after 12 hours. With time, interindividual variability decreased for the majority of measurements. Consequently, time to stabilization after insertion depends on the choice of device and is crucial to obtain valid baseline values with high degree of precision.
Combination of inductive effect of lipopolysaccharide and in situ mechanical conditioning for forming an autologous vascular graft in vivo
Authors: Chen Chao-Lin , Guo How-Ran , Wang Ying-Jan , Chang Hong-Tai , Pan Chui-Yi , Tuan-Mu Ho-Yi , Lin Hsiu-Chuan , Chen Chao-Yi , Hu Jin-Jia
Published: July 2019

Autologous vascular grafts have the advantages of better biocompatibility and prognosis. However, previous studies that implanted bare polymer tubes in animals to grow autologous tubular tissues were limited by their poor yield rates and stability. To enhance the yield rate of the tubular tissue, we employed a design with the addition of overlaid autologous whole blood scaffold containing lipopolysaccharides (LPS). Furthermore, we applied in vivo dynamic mechanical stimuli through cyclically inflatable silicone tube to improve the mechanical properties of the harvested tissues. The effectiveness of the modification was examined by implanting the tubes in the peritoneal cavity of rats. A group without mechanical stimuli served as the controls. After 24 days of culture including 16 days of cyclic mechanical stimuli, we harvested the tubular tissue forming on the silicone tube for analysis or further autologous interposition vascular grafting. In comparison with those without cyclic dynamic stimuli, tubular tissues with this treatment during in vivo culture had stronger mechanical properties, better smooth muscle differentiation, and more collagen and elastin expression by the end of incubation period in the peritoneal cavity. The grafts remained patent after 4 months of implantation and showed the presence of endothelial and smooth muscle cells. This model shows a new prospect for vascular tissue engineering.
Neurodevelopment and asymmetry of auditory-related responses to repetitive syllabic stimuli in preterm neonates based on frequency-domain analysis
Authors: Daneshvarfard Farveh , Abrishami Moghaddam Hamid , Dehaene-Lambertz Ghislaine , Kongolo Guy , Wallois Fabrice , Mahmoudzadeh Mahdi
Published: July 2019

Sensory development of the human brain begins prenatally, allowing cortical auditory responses to be recorded at an early age in preterm infants. Despite several studies focusing on the temporal characteristics of preterm infants’ cortical responses, few have been conducted on frequency analysis of these responses. In this study, we performed frequency and coherence analysis of preterm infants’ auditory responses to series of syllables and also investigated the functional brain asymmetry of preterm infants for the detection of the regularity of auditory stimuli. Cortical auditory evoked potentials (CAEPs) were recorded in 16 preterm infants with a mean recording age of 31.48 weeks gestational age (29.57–34.14 wGA) in response to a repetitive syllabic stimulus. Peak amplitudes of the frequency response at the target frequency and the first harmonic, as well as the phase coherence (PC) at the target frequency were extracted as age-dependent variables. A functional asymmetry coefficient was defined as a lateralization index for the amplitude of the target frequency at each electrode site. While the findings revealed a significant positive correlation between the mean amplitude at the target frequency vs. age (R2 = 0.263, p = 0.042), no significant correlation was observed for age-related changes of the mean amplitude at the first harmonic. A significant correlation was also observed between the mean PC and age (R2 = 0.318, p = 0.023). A right hemisphere lateralization over many channels was also generally observed. The results demonstrate that rightward lateralization for slow rate modulation, previously observed in adults, children and newborns, appears to be in place at a very young age, even in preterm infants.
Honeycomb-shaped electro-neural interface enables cellular-scale pixels in subretinal prosthesis
Authors: Flores Thomas , Huang Tiffany , Bhuckory Mohajeet , Ho Elton , Chen Zhijie , Dalal Roopa , Galambos Ludwig , Kamins Theodore , Mathieson Keith , Palanker Daniel
Published: July 2019

High-resolution visual prostheses require small, densely packed pixels, but limited penetration depth of the electric field formed by a planar electrode array constrains such miniaturization. We present a novel honeycomb configuration of an electrode array with vertically separated active and return electrodes designed to leverage migration of retinal cells into voids in the subretinal space. Insulating walls surrounding each pixel decouple the field penetration depth from the pixel width by aligning the electric field vertically, enabling a decrease of the pixel size down to cellular dimensions. We demonstrate that inner retinal cells migrate into the 25 μm deep honeycomb wells as narrow as 18 μm, resulting in more than half of these cells residing within the electrode cavities. Immune response to honeycombs is comparable to that with planar arrays. Modeled stimulation threshold current density with honeycombs does not increase substantially with reduced pixel size, unlike quadratic increase with planar arrays. This 3-D electrode configuration may enable functional restoration of central vision with acuity better than 20/100 for millions of patients suffering from age-related macular degeneration.
Precursors of seizures due to specific spatial-temporal modifications of evolving large-scale epileptic brain networks
Authors: Rings Thorsten , von Wrede Randi , Lehnertz Klaus
Published: July 2019

Knowing when, where, and how seizures are initiated in large-scale epileptic brain networks remains a widely unsolved problem. Seizure precursors – changes in brain dynamics predictive of an impending seizure – can now be identified well ahead of clinical manifestations, but either the seizure onset zone or remote brain areas are reported as network nodes from which seizure precursors emerge. We aimed to shed more light on the role of constituents of evolving epileptic networks that recurrently transit into and out of seizures. We constructed such networks from more than 3200 hours of continuous intracranial electroencephalograms recorded in 38 patients with medication refractory epilepsy. We succeeded in singling out predictive edges and predictive nodes. Their particular characteristics, namely edge weight respectively node centrality (a fundamental concept of network theory), from the pre-ictal periods of 78 out of 97 seizures differed significantly from the characteristics seen during inter-ictal periods. The vast majority of predictive nodes were connected by most of the predictive edges, but these nodes never played a central role in the evolving epileptic networks. Interestingly, predictive nodes were entirely associated with brain regions deemed unaffected by the focal epileptic process. We propose a network mechanism for a transition into the pre-seizure state, which puts into perspective the role of the seizure onset zone in this transition and highlights the necessity to reassess current concepts for seizure generation and seizure prevention.
International beeswax trade facilitates small hive beetle invasions
Authors: Idrissou Franck Ouessou , Huang Qiang , Yañez Orlando , Neumann Peter
Published: July 2019

International trade can facilitate biological invasions, but the possible role of beeswax trade for small hive beetles (SHBs), Aethina tumida Murray (Coleoptera: Nitidulidae) is poorly understood. SHBs are parasites of social bee colonies native to sub-Saharan Africa and have become an invasive species. Since 1996, SHBs have established in all continents except Antarctica. Here, we combine mitochondrial DNA analyses (COI gene, N = 296 SHBs, 98 locations) with previously published beeswax trade data (FAO) for 12 confirmed SHB invasions. Our genetic data confirm previous findings and suggest novel SHB African origins. In nine out of 12 invasion cases, the genetic and beeswax trade data match. When excluding one confirmed pathway (bee imports) and two cases, for which no FAO data were available, the genetics and beeswax trade data consistently predict the same source. This strongly suggests that beeswax imports from Ethiopia, South Africa, Tanzania and the USA, respectively, have mainly been responsible for the past invasion success of this beetle species. Adequate mitigation measures should be applied to limit this key role of beeswax imports for the further spread of SHBs. Combining genetics with trade data appears to be a powerful tool to better understand and eventually mitigate biological invasions.
Adrenergic stimulation of adiponectin secretion in visceral mouse adipocytes is blunted in high-fat diet induced obesity
Authors: Musovic Saliha , Olofsson Charlotta S.
Published: July 2019

The hormone adiponectin is secreted by white adipocytes and has been put forward as a key mediator of obesity-linked insulin resistance and the metabolic syndrome. Although adiponectin was discovered two decades ago, the knowledge about the molecular and cellular regulation of its secretion is incomplete. Here we have investigated the adrenergic regulation of adiponectin secretion in primary visceral (gonadal) adipocytes isolated from lean or obese/diabetic mice. We show that visceral adipocyte adiponectin release is triggered by cAMP/catecholamines via signalling pathways involving adrenergic beta-3-receptors (β3ARs) and Exchange Protein directly Activated by cAMP, isoform 1 (Epac1). The adrenergically stimulated adiponectin secretion is blunted in visceral adipocytes isolated from obese and diabetic mice and our results suggest the existence of a secretory defect. We have previously shown that adiponectin secretion in subcutaneous adipocytes is abolished in the obese/diabetic state due to reduced abundance of β3ARs and Epac1. However, here we show that protein levels of β3ARs and Epac1 are maintained in visceral adipocytes from obese/diabetic mice proposing that other molecular defects underlie the blunted adiponectin release. Gene expression analysis indicate diabesity-associated disturbances of the signalling downstream of Epac1 and/or the exocytotic process itself. Our study proposes that visceral adipocytes partake in the regulated secretion of adiponectin and may thus influence circulating levels of the hormone, in health and in metabolic disease.
Automation of human pluripotent stem cell differentiation toward retinal pigment epithelial cells for large-scale productions
Authors: Regent Florian , Morizur Lise , Lesueur Léa , Habeler Walter , Plancheron Alexandra , Ben M’Barek Karim , Monville Christelle
Published: July 2019

Dysfunction or death of retinal pigment epithelial (RPE) cells is involved in some forms of Retinitis Pigmentosa and in age-related macular degeneration (AMD). Since there is no cure for most patients affected by these diseases, the transplantation of RPE cells derived from human pluripotent stem cells (hPSCs) represents an attractive therapeutic alternative. First attempts to transplant hPSC-RPE cells in AMD and Stargardt patients demonstrated the safety and suggested the potential efficacy of this strategy. However, it also highlighted the need to upscale the production of the cells to be grafted in order to treat the millions of potential patients. Automated cell culture systems are necessary to change the scale of cell production. In the present study, we developed a protocol amenable for automation that combines in a sequential manner Nicotinamide, Activin A and CHIR99021 to direct the differentiation of hPSCs into RPE cells. This novel differentiation protocol associated with the use of cell culture robots open new possibilities for the production of large batches of hPSC-RPE cells while maintaining a high cell purity and functionality. Such methodology of cell culture automation could therefore be applied to various differentiation processes in order to generate the material suitable for cell therapy.
Coexisting Ordered States, Local Equilibrium-like Domains, and Broken Ergodicity in a Non-turbulent Rayleigh-Bénard Convection at Steady-state
Authors: Chatterjee Atanu , Yadati Yash , Mears Nicholas , Iannacchione Germano
Published: July 2019

A challenge in fundamental physics and especially in thermodynamics is to understand emergent order in far-from-equilibrium systems. While at equilibrium, temperature plays the role of a key thermodynamic variable whose uniformity in space and time defines the equilibrium state the system is in, this is not the case in a far-from-equilibrium driven system. When energy flows through a finite system at steady-state, temperature takes on a time-independent but spatially varying character. In this study, the convection patterns of a Rayleigh-Bénard fluid cell at steady-state is used as a prototype system where the temperature profile and fluctuations are measured spatio-temporally. The thermal data is obtained by performing high-resolution real-time infrared calorimetry on the convection system as it is first driven out-of-equilibrium when the power is applied, achieves steady-state, and then as it gradually relaxes back to room temperature equilibrium when the power is removed. Our study provides new experimental data on the non-trivial nature of thermal fluctuations when stable complex convective structures emerge. The thermal analysis of these convective cells at steady-state further yield local equilibrium-like statistics. In conclusion, these results correlate the spatial ordering of the convective cells with the evolution of the system’s temperature manifold.
Pyruvate Plays a Main Role in the Antitumoral Selectivity of Cold Atmospheric Plasma in Osteosarcoma
Authors: Tornin Juan , Mateu-Sanz Miguel , Rodríguez Aida , Labay Cédric , Rodríguez Rene , Canal Cristina
Published: July 2019

Osteosarcoma (OS) is the most common primary bone tumor but current therapies still have poor prognosis. Cold Atmospheric Plasma (CAP) and Plasma activated media (PAM) have shown potential to eliminate cancer cells in other tumors. It is thought that Reactive Oxygen and Nitrogen species (RONS) in PAM are key players but cell culture media composition alters treatment outcomes and data interpretation due to scavenging of certain RONS. In this work, an atmospheric pressure plasma jet was employed to obtain PAM in the presence or absence of pyruvate and used to treat the SaOS-2 (OS) cell line or hBM-MSC healthy cells. OS cells show higher sensitivity to PAM treatment than healthy cells, both in medium with and without pyruvate, activating apoptosis, DNA damage and deregulating cellular pathways mediated by c-JUN, AKT, AMPK or STAT3. In line with previous works, lack of pyruvate increases cytotoxic potential of PAM affecting cancer and healthy cells by increasing 10–100 times the concentration of H2O2 without altering that of nitrites and thus decreasing CAP anti-tumor selectivity. Suitable conditions for CAP anti-cancer selectivity can be obtained by modifying plasma process parameters (distance, flow, treatment time) to obtain adequate balance of the different RONS in cell culture media.
A regime-switching SIR epidemic model with a ratio-dependent incidence rate and degenerate diffusion
Authors: Cao Zhongwei , Liu Xu , Wen Xiangdan , Liu Liya , Zu Li
Published: July 2019

In this paper, we present a regime-switching SIR epidemic model with a ratio-dependent incidence rate and degenerate diffusion. We utilize the Markov semigroup theory to obtain the existence of a unique stable stationary distribution. We prove that the densities of the distributions of the solutions can converge in L1 to an invariant density under certain condition. Moreover, the sufficient conditions for the extinction of the disease, which means the disease will die out with probability one, are given in two cases. Meanwhile, we obtain a threshold parameter which can be utilized in identifying the stochastic extinction and persistence of the disease. Some numerical simulations are given to illustrate the analytical results.
In Silico Characterization of the Binding Modes of Surfactants with Bovine Serum Albumin
Authors: Nnyigide Osita Sunday , Lee Sun-Gu , Hyun Kyu
Published: July 2019

The binding interactions of the surfactants: anionic sodium dodecyl sulphate (SDS), cationic cetyltrimethylammonium bromide (CTAB), non-ionic octyl glucoside (OG), and zwitterionic 3-[Hexadecyl(dimethyl)ammonio]-1-propanesulfonate (HPS), with bovine serum albumin (BSA) were investigated by computer simulation. The results disclosed that the surfactants bound stably between hydrophobic subdomain IIA and IIIA where tryptophan-213 residue, an important intrinsic fluorophore in BSA is housed. The interactions of the surfactants with the BSA were electrostatic and hydrophobic interactions. The head-groups of SDS, HPS and OG formed hydrogen bonds with the BSA, while that of CTAB was shielded from intermolecular hydrogen-bonding due to intervening methyl groups. Subsequently, molecular dynamics (MD) simulation of the protein-surfactant complexes revealed that hydrogen bonds formed by OG were stronger than those of SDS and HPS. However, the decomposed force-field energies showed that OG had the least interaction energy with the BSA. In addition to MD simulation, it was found by density functional theory (DFT) that the differences in the coulomb interaction energies can be attributed to charge distribution in the surfactants. Overall, free energies calculated by linear interaction energy (LIE) proved that the binding of each surfactant was dominated by differences between van der Waals interactions in bound and free states.
Characterization of Organic Layer in Oil Carbonate Reservoir Rocks and its Effect on Microscale Wetting Properties
Authors: Ivanova Anastasia , Mitiurev Nikolai , Cheremisin Alexey , Orekhov Anton , Kamyshinsky Roman , Vasiliev Alexander
Published: July 2019

Effective production of oil from carbonate reservoirs often requires the application of improved oil recovery technologies such as waterflooding. However, conventional waterflooding in carbonates usually results in low hydrocarbon recovery as most of these formations exhibit a complex pore throats structure and are mostly oil-wet. Therefore, improved insight into the causes of hydrophobic wetting behavior of such reservoirs is important for understanding the fluid distribution, displacement and enhancing recovery processes. The characterization of fluid-rock interactions is, however, challenging with existing laboratory methods, which are typically based on macroscale (mm) observations. In this experimental study, an advanced imaging technique, namely environmental scanning electron microscope, was applied for the comprehensive investigation of microscale (µm) wettability variations in carbonate rocks covered with organic layers. For the first time, the presence of organic layers on the sample was proved using energy dispersive X-ray mapping. Furthermore, the chemical bond of this layer and carbonate rock surfaces was determined using the transmission electron microscopy and electron energy-loss spectroscopy. The thickness of layer was estimated by using image processing software. These findings show that the application of combined microscopic techniques reveals important details about the reason of hydrophobic wetting properties of real carbonate rocks.
The prognostic role of platelet-to-lymphocyte ratio in patients with acute heart failure: A cohort study
Authors: Ye Gui-lian , Chen Qiang , Chen Xueyu , Liu Ying-ying , Yin Ting-ting , Meng Qing-he , Liu Ying-chao , Wei Huai-qing , Zhou Qing-hua
Published: July 2019

Identification of rapid, inexpensive, and reliable prognostic factors can improve survival estimation and guide healthcare in patients with acute heart failure (AHF). In this study, we aimed to determine the prognostic value of the platelet-to-lymphocyte ratio (PLR) in patients with AHF. A total of 443 patients from two hospitals met the inclusion criteria from January 2010 to December 2017. Univariate and multivariate Cox analyses were performed to determine the association of PLR with survival. All-cause mortality was analysed using the Kaplan-Meier method. The 6-month survival rate for patients according to PLR quartiles (<110.63, 110.63–139.23, 139.23–177.17, and >177.17) were 90.09%, 76.79%, 50.07%, and 37.27%, respectively (p < 0.001). Univariate analysis identified high PLR (>110.63), old age (≥73 years), smoking habit, low estimated glomerular filtration rate (<57), and high platelet count (≥198 × 109/l) as poor prognostic factors for survival. In the multivariate analysis, after adjusting for confounding factors, the third (hazard ratio [HR] = 3.118, 95% confidence interval [CI] = 1.668–5.386, p < 0.001) and fourth (HR = 2.437, 95% CI = 1.302–3.653, p < 0.001) quartiles of PLR were identified as independent prognostic factors in patients with AHF. A higher PLR was associated with poor clinical outcomes in patients with AHF and might be a novel marker in AHF management.
A novel method for assessing microplastic effect in suspension through mixing test and reference materials
Authors: Gerdes Zandra , Hermann Markus , Ogonowski Martin , Gorokhova Elena
Published: July 2019

The occurrence of microplastic in the environment is of global concern. However, the microplastic hazard assessment is hampered by a lack of adequate ecotoxicological methods because of conceptual and practical problems with particle exposure. In the environment, suspended solids (e.g., clay and cellulose) in the same size range as microplastic, are ubiquitous. Therefore, it must be established whether the addition of microplastic to these background levels of particulate material represents a hazard. We present a novel approach employing a serial dilution of microplastic and reference particles, in mixtures, which allows disentangling the effect of the microplastic from that of the other particulates. We demonstrate the applicability of the method using an immobilization test with Daphnia magna exposed to polyethylene terephthalate (test microplastic; median particle diameter ~5 µm) and kaolin clay (reference material; ~3 µm). In the range of the suspended solids test concentrations (0–10 000 mg L−1), with microplastic contributing 0–100% of total mass, the LC50 values for the plastic mixtures were significantly lower compared to the kaolin exposure. Hence, the exposure to polyethylene terephthalate was more harmful to the daphnids than to the reference material alone. The estimated threshold for the relative contribution of the test microplastic to suspended matter above which significantly higher mortality was observed was 2.4% at 32 mg of the solids L−1. This approach has a potential for standardization of ecotoxicological testing of particulates, including microplastic.
Identification of hepadnavirus in the sera of cats
Authors: Lanave Gianvito , Capozza Paolo , Diakoudi Georgia , Catella Cristiana , Catucci Leonardo , Ghergo Paola , Stasi Fabio , Barrs Vanessa , Beatty Julia , Decaro Nicola , Buonavoglia Canio , Martella Vito , Camero Michele
Published: July 2019

Hepadnaviruses infect several animal species. The prototype species, human hepatitis B virus (HBV), increases the risk of liver diseases and may cause cirrhosis and hepatocellular carcinoma. Recently a novel hepadnavirus, similar to HBV, has been identified through transcriptomics studies in a domestic cat with large cell lymphoma in Australia. Herewith, a collection of 390 feline serum samples was screened for hepadnavirus. Overall, the virus was identified in 10.8% of the sera with a significantly higher prevalence (17.8%) in the sera of animals with a clinical suspect of infectious disease. Upon genome sequencing, the virus was closely related (97.0% nt identity) to the prototype Australian feline virus Sydney 2016. The mean and median values of hepadnavirus in the feline sera were 1.3 × 106 and 2.1 × 104 genome copies per mL (range 3.3 × 100–2.5 × 107 genome copies per mL). For a subset of hepadnavirus-positive samples, information on the hemato-chemical parameters was available and in 10/20 animals a profile suggestive of liver damage was present. Also, in 7/10 animals with suspected hepatic disease, virus load was >104 genome copies per mL, i.e. above the threshold considered at risk of active hepatitis and liver damage for HBV.
Neurocognitive Signatures of Naturalistic Reading of Scientific Texts: A Fixation-Related fMRI Study
Authors: Hsu Chun-Ting , Clariana Roy , Schloss Benjamin , Li Ping
Published: July 2019

How do students gain scientific knowledge while reading expository text? This study examines the underlying neurocognitive basis of textual knowledge structure and individual readers’ cognitive differences and reading habits, including the influence of text and reader characteristics, on outcomes of scientific text comprehension. By combining fixation-related fMRI and multiband data acquisition, the study is among the first to consider self-paced naturalistic reading inside the MRI scanner. Our results revealed the underlying neurocognitive patterns associated with information integration of different time scales during text reading, and significant individual differences due to the interaction between text characteristics (e.g., optimality of the textual knowledge structure) and reader characteristics (e.g., electronic device use habits). Individual differences impacted the amount of neural resources deployed for multitasking and information integration for constructing the underlying scientific mental models based on the text being read. Our findings have significant implications for understanding science reading in a population that is increasingly dependent on electronic devices.
Prevalence of healthy lifestyles against cancer in Spanish women
Authors: Toribio María José , Lope Virginia , Castelló Adela , Salas Dolores , Vidal Carmen , Ascunce Nieves , Santamariña Carmen , Moreo Pilar , Pedraz-Pingarrón Carmen , Sánchez-Contador Carmen , Aragonés Nuria , Pérez-Gómez Beatriz , Pollán Marina
Published: July 2019

Modifying behavior towards healthier lifestyles could prevent a significant number of malignant tumors. We evaluated the prevalence of healthy habits against cancer in Spanish women free of this disease, taking as a reference the recommendations for cancer prevention included in the European Code Against Cancer (ECAC), and we explored the characteristics associated with it. Our population comprised 3,584 women recruited in a population-based cross-sectional study carried out in 7 breast cancer screening programs. Information was directly surveyed and used to calculate a score based on ECAC recommendations referred to bodyweight, physical activity, diet, breastfeeding, tobacco, alcohol and hormone replacement therapy use. The degree of adherence was estimated with a score that evaluated null (0 points), partial (0.5 points) and full adherence (1 point) of each specific recommendation. Associations were explored using binary and ordinal logistic regression models. The median score was 5.7 out of 9 points. Recommendations with lower adherence were those related to intake of red/processed meat and foods high in salt (23% of total adherence), physical activity (24%) and body weight (29%), and recommendations with greater adherence where those related to hormone replacement therapy use (91%), vegetable intake (84%), alcohol (83%) and tobacco (61%). Overall adherence was better among older women, parous women, and in those living in rural areas, and worse among women with higher caloric intake. These recommendations should be evaluated periodically. Screening programs can be an appropriate place to disseminate this information.
Extreme Arsenic Bioaccumulation Factor Variability in Lake Titicaca, Bolivia
Authors: Sarret Géraldine , Guédron Stéphane , Acha Dario , Bureau Sarah , Arnaud-Godet Florent , Tisserand Delphine , Goni-Urriza Marisol , Gassie Claire , Duwig Céline , Proux Olivier , Aucour Anne-Marie
Published: July 2019

Latin America, like other areas in the world, is faced with the problem of high arsenic (As) background in surface and groundwater, with impacts on human health. We studied As biogeochemical cycling by periphyton in Lake Titicaca and the mine-impacted Lake Uru Uru. As concentration was measured in water, sediment, totora plants (Schoenoplectus californicus) and periphyton growing on stems, and As speciation was determined by X-ray absorption spectroscopy in bulk and EDTA-extracted periphyton. Dissolved arsenic was between 5.0 and 15 μg L−1 in Lake Titicaca and reached 78.5 μg L−1 in Lake Uru Uru. As accumulation in periphyton was highly variable. We report the highest As bioaccumulation factors ever measured (BAFsperiphyton up to 245,000) in one zone of Lake Titicaca, with As present as As(V) and monomethyl-As (MMA(V)). Non-accumulating periphyton found in the other sites presented BAFsperiphyton between 1281 and 11,962, with As present as As(III), As(V) and arsenosugars. DNA analysis evidenced several taxa possibly related to this phenomenon. Further screening of bacterial and algal isolates would be necessary to identify the organism(s) responsible for As hyperaccumulation. Impacts on the ecosystem and human health appear limited, but such organisms or consortia would be of great interest for the treatment of As contaminated water.
Dose-dependent metabolite changes after ethanol intoxication in rat prefrontal cortex using in vivo magnetic resonance spectroscopy
Authors: Carton Louise , Auger Florent , Kyheng Maeva , Pétrault Maud , Durieux Nicolas , Allorge Delphine , Cottencin Olivier , Jardri Renaud , Bordet Régis , Rolland Benjamin
Published: July 2019

Ethanol disrupts the balance between the excitatory (glutamatergic) and inhibitory (GABAergic) neurotransmission systems. We aimed to assess how acute ethanol intoxication in rats affects the levels of GABA, glutamate and other cerebral metabolites after injection of two different doses of ethanol. One in vivo magnetic resonance spectrum of the prefrontal cortex region was acquired before and six spectra were acquired after intraperitoneal injections of saline or ethanol (1 g/kg or 2 g/kg). Brain kinetics after exposure to ethanol were compared to blood ethanol kinetics. GABA levels significantly decreased after injection of 1 g/kg but not 2 g/kg doses of ethanol. Choline levels, which serve as a marker of alterations in membrane composition, significantly decreased after injection of 2 g/kg but not 1 g/kg doses of ethanol. Acute ethanol intoxication appears to result in specific dose-dependent changes in the GABA level and choline level.
City-wide electronic health records reveal gender and age biases in administration of known drug–drug interactions
Authors: Brattig Correia Rion , de Araújo Kohler Luciana P. , Mattos Mauro M. , Rocha Luis M.
Published: July 2019

The occurrence of drug–drug-interactions (DDI) from multiple drug dispensations is a serious problem, both for individuals and health-care systems, since patients with complications due to DDI are likely to reenter the system at a costlier level. We present a large-scale longitudinal study (18 months) of the DDI phenomenon at the primary- and secondary-care level using electronic health records (EHR) from the city of Blumenau in Southern Brazil (pop. ≈340,000). We found that 181 distinct drug pairs known to interact were dispensed concomitantly to 12% of the patients in the city’s public health-care system. Further, 4% of the patients were dispensed drug pairs that are likely to result in major adverse drug reactions (ADR)—with costs estimated to be much larger than previously reported in smaller studies. The large-scale analysis reveals that women have a 60% increased risk of DDI as compared to men; the increase becomes 90% when considering only DDI known to lead to major ADR. Furthermore, DDI risk increases substantially with age; patients aged 70–79 years have a 34% risk of DDI when they are dispensed two or more drugs concomitantly. Interestingly, a statistical null model demonstrates that age- and female-specific risks from increased polypharmacy fail by far to explain the observed DDI risks in those populations, suggesting unknown social or biological causes. We also provide a network visualization of drugs and demographic factors that characterize the DDI phenomenon and demonstrate that accurate DDI prediction can be included in health care and public-health management, to reduce DDI-related ADR and costs.
Author Correction: Deep learning versus human graders for classifying diabetic retinopathy severity in a nationwide screening program
Authors: Ruamviboonsuk Paisan , Krause Jonathan , Chotcomwongse Peranut , Sayres Rory , Raman Rajiv , Widner Kasumi , Campana Bilson J. L. , Phene Sonia , Hemarat Kornwipa , Tadarati Mongkol , Silpa-Archa Sukhum , Limwattanayingyong Jirawut , Rao Chetan , Kuruvilla Oscar , Jung Jesse , Tan Jeffrey , Orprayoon Surapong , Kangwanwongpaisan Chawawat , Sukumalpaiboon Ramase , Luengchaichawang Chainarong , Fuangkaew Jitumporn , Kongsap Pipat , Chualinpha Lamyong , Saree Sarawuth , Kawinpanitan Srirut , Mitvongsa Korntip , Lawanasakol Siriporn , Thepchatri Chaiyasit , Wongpichedchai Lalita , Corrado Greg S. , Peng Lily , Webster Dale R.
Published: July 2019

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Porphyrin functionalized Co(OH)2/GO nanocomposites as an excellent peroxidase mimic for colorimetric biosensing
Authors: Zhao Xin , Wu Kaili , Lyu Haoyuan , Zhang Xianxi , Liu Zhenxue , Fan Gaochao , Zhang Xiao , Zhu Xixi , Liu Qingyun
Published: July 2019

A colorimetric sensor based on the enhanced peroxidase-like activity of Por/Co(OH)2/GO for the sensitive detection of H2O2 and GSH.
Multi-approach cysteine detection based on supramolecular transformation induced by G-quadruplexes
Authors: Yang Dawei , Chen Hongbo , Li Qian , Zhang Xiufeng , Sun Hongxia , Tang Yalin
Published: July 2019

Cysteine detection based on supramolecular transformation induced by G-quadruplexes.
Activity-based protein profiling reveals that secondary-carbon-centered radicals of synthetic 1,2,4-trioxolanes are predominately responsible for modification of protein targets in malaria parasites
Authors: Wei Chunyan , Zhao Cheng-Xiao , Liu Sheng , Zhao Jin-Hui , Ye Zi , Wang Heng , Yu Shi-Shan , Zhang Chong-Jing
Published: July 2019

By means of rational probe design and activity-based protein profiling (ABPP), we found that the secondary-carbon-centered radical predominates in protein targeting of synthetic trioxolane in malaria parasites.
Humidity-triggered single-crystal-to-single-crystal structural transformations in a Zn(ii) coordination polymer displaying unusual activation energy change in proton conductivity
Authors: Song Jeong Hwa , Kim Dae Won , Kang Dong Won , Lee Woo Ram , Hong Chang Seop
Published: July 2019

Sequential single crystal-to-single crystal transformations occur in a Zn(ii)-based coordination polymer, revealing an unusual change in the activation energy for proton conduction.
A novel “signal on” photoelectrochemical strategy based on dual functional hemin for microRNA assay
Authors: Xia Ling-Ying , Li Meng-Jie , Wang Hai-Jun , Yuan Ruo , Chai Ya-Qin
Published: July 2019

Here, a novel “signal on” photoelectrochemistry (PEC) biosensor was constructed by dual functional hemin as signal quencher and electronic mediator for ultrasensitive target microRNA-141 assay with the assistance of T7 exonuclease (Exo)-initiated target amplification technology.
Highlights from Faraday Discussion on Ultrafast Photoinduced Energy and Charge Transfer, Ventura, CA, USA, April 2019
Authors: Woolley J. M. , Krokidi K. M. , Turner M. A. P. , Horbury M. D. , Stavros V. G. , Rodrigues N. d. N.
Published: July 2019

A Faraday Discussion meeting was held on the topic of ‘Ultrafast Energy and Charge Transfer’. This report covers the highlights of this meeting, including brief summaries of the papers discussed and particularly interesting or recurring topics of the ensuing discussion.