bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacogenetics in Model-Based Optimization of Bevacizumab Therapy for Metastatic Colorectal Cancer
Authors: Papachristos Apostolos , Karatza Eleni , Kalofonos Haralabos , Sivolapenko Gregory
Published: May 2020

Vascular endothelial growth factor A (VEGF-A) and intercellular adhesion molecule 1 (ICAM-1) are significant regulators of angiogenesis, an important biological process involved in carcinogenesis. Bevacizumab, an anti-VEGF monoclonal antibody (MAB), is approved for the treatment of metastatic Colorectal cancer (mCRC), however clinical outcomes are highly variable. In the present study, we developed a pharmacokinetic (PK), a simplified quasi-steady state (QSS) and a pharmacokinetic/pharmacodynamic (PK/PD) model to identify potential sources of variability. A total of 46 mCRC patients, who received bevacizumab in combination with chemotherapy were studied. VEGF-A (rs2010963, rs1570360, rs699947) and ICAM-1 (rs5498, rs1799969) genes’ polymorphisms, age, gender, weight, and dosing scheme were investigated as possible co-variates of the model’s parameters. Polymorphisms, trough, and peak levels of bevacizumab, and free VEGF-A were determined in whole blood and serum. Data were analyzed using nonlinear mixed-effects modeling. The two-compartment PK model showed that clearance (CL) was significantly lower in patients with mutant ICAM-1 rs1799969 (p < 0.0001), inter-compartmental clearance (Q) was significantly higher with mutant VEGF-A rs1570360 (p < 0.0001), and lower in patients with mutant VEGF-A rs699947 (p < 0.0001). The binding QSS model also showed that mutant ICAM-1 rs1799969 was associated with a lower CL (p = 0.0177). Mutant VEGF-A rs699947 was associated with a lower free VEGF-A levels, prior to the next dose (p = 0.000445). The above results were confirmed by the PK/PD model. Findings of the present study indicated that variants of the genes regulating angiogenesis might affect PK and PD characteristics of bevacizumab, possibly influencing the clinical outcomes.
Identification and Expression Profiling of Toll-Like Receptors of Brown Trout (Salmo trutta) during Proliferative Kidney Disease
Authors: Sudhagar Arun , El-Matbouli Mansour , Kumar Gokhlesh
Published: May 2020

Proliferative kidney disease is an emerging disease among salmonids in Europe and North America caused by the myxozoan parasite Tetracapsuloides bryosalmonae. The decline of endemic brown trout (Salmo trutta) in the Alpine streams of Europe is fostered by T. bryosalmonae infection. Toll-like receptors (TLRs) are a family of pattern recognition receptors that acts as sentinels of the immune system against the invading pathogens. However, little is known about the TLRs’ response in salmonids against the myxozoan infection. In the present study, we identified and evaluated TLR1, TLR19, and TLR13-like genes of brown trout using data-mining and phylogenetic analysis. The expression pattern of TLRs was examined in the posterior kidney of brown trout infected with T. bryosalmonae at various time points. Typical Toll/interleukin-1 receptor protein domain was found in all tested TLRs. However, TLR13-like chr2 had a short amino acid sequence with no LRR domain. Phylogenetic analysis illustrated that TLR orthologs are conserved across vertebrates. Similarly, a conserved synteny gene block arrangement was observed in the case of TLR1 and TLR19 across fish species. Interestingly, all tested TLRs showed their maximal relative expression from 6 to 10 weeks post-exposure to the parasite. Our results suggest that these TLRs may play an important role in the innate defense mechanism of brown trout against the invading T. bryosalmonae.
Activation of Mitochondrial 2-Oxoglutarate Dehydrogenase by Cocarboxylase in Human Lung Adenocarcinoma Cells A549 Is p53/p21-Dependent and Impairs Cellular Redox State, Mimicking the Cisplatin Action
Authors: Bunik Victoria I. , Aleshin Vasily A. , Zhou Xiaoshan , Tabakov Vyacheslav Yu. , Karlsson Anna
Published: May 2020

Genetic up-regulation of mitochondrial 2-oxoglutarate dehydrogenase is known to increase reactive oxygen species, being detrimental for cancer cells. Thiamine diphosphate (ThDP, cocarboxylase) is an essential activator of the enzyme and inhibits p53–DNA binding in cancer cells. We hypothesize that the pleiotropic regulator ThDP may be of importance for anticancer therapies. The hypothesis is tested in the present work on lung adenocarcinoma cells A549 possessing the p53–p21 pathway as fully functional or perturbed by p21 knockdown. Molecular mechanisms of ThDP action on cellular viability and their interplay with the cisplatin and p53–p21 pathways are characterized. Despite the well-known antioxidant properties of thiamine, A549 cells exhibit decreases in their reducing power and glutathione level after incubation with 5 mM ThDP, not observed in non-cancer epithelial cells Vero. Moreover, thiamine deficiency elevates glutathione in A549 cells. Viability of the thiamine deficient A549 cells is increased at a low (0.05 mM) ThDP. However, the increase is attenuated by 5 mM ThDP, p21 knockdown, specific inhibitor of the 2-oxoglutarate dehydrogenase complex (OGDHC), or cisplatin. Cellular levels of the catalytically competent ThDP·OGDHC holoenzyme are dysregulated by p21 knockdown and correlate negatively with the A549 viability. The inverse relationship between cellular glutathione and holo-OGDHC is corroborated by their comparison in the A549 and Vero cells. The similarity, non-additivity, and p21 dependence of the dual actions of ThDP and cisplatin on A549 cells manifest a common OGDHC-mediated mechanism of the viability decrease. High ThDP saturation of OGDHC compromises the redox state of A549 cells under the control of p53–p21 axes.
rhBMP-2 Pre-Treated Human Periodontal Ligament Stem Cell Sheets Regenerate a Mineralized Layer Mimicking Dental Cementum
Authors: Park Joo-Young , Park Chan Ho , Yi TacGhee , Kim Si-na , Iwata Takanori , Yun Jeong-Ho
Published: May 2020

The periodontal complex consisting of alveolar bone, cementum, and periodontal ligaments (PDL) supports human teeth through the systematic orchestration of mineralized tissues and fibrous tissues. Importantly, cementum, the outermost mineralized layer of dental roots, plays an essential role by bridging the inner ligaments from the dental root to the alveolar bone. When the periodontal complex is damaged, the regeneration of each component of the periodontal complex is necessary; however, it is still challenging to achieve complete functional regeneration. In this study, we tried to control the regeneration of cementum and PDL by using a human PDL stem cell (hPDLSC) sheet engineering technology with the pretreatment of recombinant human BMP-2 (rhBMP-2). Isolated hPDLSCs obtained from extracted human teeth were pretreated with rhBMP-2 for in vitro osteogenic differentiation and grafted on the micro/macro-porous biphasic calcium phosphate (MBCP) blocks, which represent dental roots. The MBCPs with hPDLSC sheets were implanted in the subcutaneous layer of immune-compromised mice, and rhBMP-2 pretreated hPDLSC sheets showed higher mineralization and collagen ligament deposition than the no-pretreatment group. Therefore, the rhBMP-2-hPDLSC sheet technique could be an effective strategy for the synchronized regeneration of two different tissues: mineralized tissue and fibrous tissues in periodontal complexes.
Mg2+ is a Missing Link in Plant Cell Ca2+ Signalling and Homeostasis—A Study on Vicia faba Guard Cells
Authors: Lemtiri-Chlieh Fouad , Arold Stefan T. , Gehring Chris
Published: May 2020

Hyperpolarization-activated calcium channels (HACCs) are found in the plasma membrane and tonoplast of many plant cell types, where they have an important role in Ca2+-dependent signalling. The unusual gating properties of HACCs in plants, i.e., activation by membrane hyperpolarization rather than depolarization, dictates that HACCs are normally open in the physiological hyperpolarized resting membrane potential state (the so-called pump or P-state); thus, if not regulated, they would continuously leak Ca2+ into cells. HACCs are permeable to Ca2+, Ba2+, and Mg2+; activated by H2O2 and the plant hormone abscisic acid (ABA); and their activity in guard cells is greatly reduced by increasing amounts of free cytosolic Ca2+ ([Ca2+]Cyt), and hence closes during [Ca2+]Cyt surges. Here, we demonstrate that the presence of the commonly used Mg-ATP inside the guard cell greatly reduces HACC activity, especially at voltages ≤ −200 mV, and that Mg2+ causes this block. Therefore, we firstly conclude that physiological cytosolic Mg2+ levels affect HACC gating and that channel opening requires either high negative voltages (≥−200 mV) or displacement of Mg2+ away from the immediate vicinity of the channel. Secondly, based on structural comparisons with a Mg2+-sensitive animal inward-rectifying K+ channel, we propose that the likely candidate HACCs described here are cyclic nucleotide gated channels (CNGCs), many of which also contain a conserved diacidic Mg2+ binding motif within their pores. This conclusion is consistent with the electrophysiological data. Finally, we propose that Mg2+, much like in animal cells, is an important component in Ca2+ signalling and homeostasis in plants.
Cell Wall Anchoring of a Bacterial Chitosanase in Lactobacillus plantarum Using a Food-Grade Expression System and Two Versions of an LP × TG Anchor
Authors: Pham Mai-Lan , Tran Anh-Minh , Mathiesen Geir , Nguyen Hoang-Minh , Nguyen Thu-Ha
Published: May 2020

Lactic acid bacteria (LAB) have attracted increasing interest recently as cell factories for the production of proteins as well as a carrier of proteins that are of interest for food and therapeutic applications. In this present study, we exploit a lactobacillal food-grade expression system derived from the pSIP expression vectors using the alr (alanine racemase) gene as the selection marker for the expression and cell-surface display of a chitosanase in Lactobacillus plantarum using two truncated forms of a LP × TG anchor. CsnA, a chitosanase from Bacillus subtilis 168 (ATCC23857), was fused to two different truncated forms (short-S and long-L anchors) of an LP × TG anchor derived from Lp_1229, a key-protein for mannose-specific adhesion in L. plantarum WCFS1. The expression and cell-surface display efficiency driven by the food-grade alr-based system were compared with those obtained from the erm-based pSIP system in terms of enzyme activities and their localisation on L. plantarum cells. The localization of the protein on the bacterial cell surface was confirmed by flow cytometry and immunofluorescence microscopy. The highest enzymatic activity of CsnA-displaying cells was obtained from the strain carrying the alr-based expression plasmid with short cell wall anchor S. However, the attachment of chitosanase on L. plantarum cells via the long anchor L was shown to be more stable compared with the short anchor after several repeated reaction cycles. CsnA displayed on L. plantarum cells is catalytically active and can convert chitosan into chito-oligosaccharides, of which chitobiose and chitotriose are the main products.
Development and Validation of an in-House Library of Colombian Candida auris Strains with MALDI-TOF MS to Improve Yeast Identification
Authors: Ceballos-Garzon Andrés , Amado Daniela , Vélez Norida , Jiménez-A María José , Rodríguez Crescencio , Parra-Giraldo Claudia Marcela
Published: May 2020

Background: Candida auris is characterized for having a high genetic variability among species. MALDI-TOF MS library contains spectra from only three strains of C. auris, which makes difficult the identification process and gives low scores at the species level. Our aim was to construct and validate an internal library to improve C. auris identification with Colombian clinical strains. Methods: From 30 clinical strains, 770 mass spectra were obtained for the construction of the database. The validation was performed with 300 strains to compare the identification results in the BDAL and C. auris Colombia libraries. Results: Our library allowed a complete, 100% identification of the evaluated strains and a significant improvement in the scores obtained, showing a better performance compared to the Bruker BDAL library. Conclusions: The strengthening of the database is a great opportunity to improve the scoring and C. auris identification. Library data are available via ProteomeXchange with identifier PXD016387.
Assessment of the Mechanical Properties of ESD Pseudoplastic Resins for Joints in Working Elements of Concrete Structures
Authors: Logoń Dominik , Schabowicz Krzysztof , Wróblewski Krzysztof
Published: May 2020

Concrete structure joints are filled in mainly in the course of sealing works ensuring protection against the influence of water. This paper presents the methodology of testing the mechanical properties of ESD pseudoplastic resins (E-elastic deformation, S-strengthening control, D-deflection control) recommended for concrete structure joint fillers. The existing standards and papers concerning quasi-brittle cement composites do not provide an adequate point of reference for the tested resins. The lack of a standardised testing method hampers the development of materials universally used in expansion joint fillers in reinforced concrete structures as well as the assessment of their properties and durability. An assessment of the obtained results by reference to the reference sample has been suggested in the article. A test stand and a method of assessing the mechanical properties results (including adhesion to concrete surface) of pseudoplastic resins in the axial tensile test have been presented.
Temporal and Spatial Detection of the Onset of Local Necking and Assessment of its Growth Behavior
Authors: Jaremenko Christian , Affronti Emanuela , Merklein Marion , Maier Andreas
Published: May 2020

This study proposes a method for the temporal and spatial determination of the onset of local necking determined by means of a Nakajima test set-up for a DC04 deep drawing and a DP800 dual-phase steel, as well as an AA6014 aluminum alloy. Furthermore, the focus lies on the observation of the progress of the necking area and its transformation throughout the remainder of the forming process. The strain behavior is learned by a machine learning approach on the basis of the images when the process is close to material failure. These learned failure characteristics are transferred to new forming sequences, so that critical areas indicating material failure can be identified at an early stage, and consequently enable the determination of the beginning of necking and the analysis of the necking area. This improves understanding of the necking behavior and facilitates the determination of the evaluation area for strain paths. The growth behavior and traceability of the necking area is objectified by the proposed weakly supervised machine learning approach, thereby rendering a heuristic-based determination unnecessary. Furthermore, a simultaneous evaluation on image and pixel scale is provided that enables a distinct selection of the failure quantile of the probabilistic forming limit curve.
Investigation on the Microstructure and Wear Behavior of Laser-Cladded High Aluminum and Chromium Fe-B-C Coating
Authors: Li Jingjing , Ju Jiang , Chang Weiwei , Yang Chao , Wang Jun
Published: May 2020

In this study, a high aluminum and chromium Fe-B-C coating was prepared using laser cladding on 2Cr13 steel substrate. The microstructure, microhardness, and wear resistance of the high aluminum and chromium Fe-B-C coating were investigated. The results show that this dense coating possesses good metallurgical bond with the substrate. The microstructure is mainly composed of α-(Fe, Cr, Al) lath martensite, orthorhombic M2B boride, orthogonal M3C2, and orthorhombic M7C3 carbides. The microhardness of the coating can reach 620 HV which is 3.3-times higher than that (190 HV) of the substrate. The coating shows a lower friction coefficient of 0.75 than that of the substrate (1.08). The wear rates of the substrate and the coating are 0.295 mg/min and 0.103 mg/min, respectively, indicating the coating exhibits excellent wear resistance. The wear mechanism transforms severe adhesive wear and abrasive wear of the substrate to slight abrasive wear of the coating. The results can provide technical support to improve the properties of the Fe-based laser cladded coating.
Effect of Post-Heat Treatment on the AISI M4 Layer Deposited by Directed Energy Deposition
Authors: Baek Gyeong Yun , Shin Gwang Yong , Lee Ki Yong , Shim Do Sik
Published: May 2020

Currently, high-speed steel (HSS) powders are deposited locally on a metal surface through direct energy deposition (DED) onto hardface tool steel. Although the HSS powder enhances the hardness and the abrasion resistance of a metal surface, it makes the tool steel brittle because of its high carbon content. In addition, the steel is likely to break when subjected to a high load over time. This study focused on improving the steel toughness by applying a post-heat treatment. To fabricate a uniformly deposited layer through DED, M4 powder was deposited onto a pre-heated substrate (AISI D2). In addition, four post-heat-treated specimens were prepared, and their mechanical properties were compared. The Charpy impact and hardness tests were conducted to evaluate the durability required for the D2 die. The deposited M4 powder possessed a high hardness but a relatively low impact toughness. During laser melting, a stable bond formed between M4 and D2 without any cracks or delamination. The hardness of the initial M4 deposited layer was 63 HRC, which changed to 54–63 HRC depending on the effect of the post-heat treatment. Moreover, the post-heat-treatment process improves the impact toughness of the M4 deposited layer by changing its microstructure.
Formability of Medium Mn Steel Welded Joints
Authors: Cao Yang , Wang Bo , Zhao Lin , Peng Yun , Zhong Minlin , Zuo Hong , Tian Zhiling
Published: May 2020

In this study, a new-generation high-strength and high-ductility medium Mn steel (0.1C-5Mn-Fe) for the automotive industry was joined by the fiber laser and gas tungsten arc welding (GTAW) methods. Formability testing of the welded joints was done by the Erichsen cupping test and finite element (FE) analysis. The results showed that the formability of medium Mn steel welded joints was sensitive to the welding parameters and inferior to that of the base metal (BM). The hardening zone (HZ) was formed in the welded joint, which was composed of the fusion zone and two symmetrical parts of the heat-affected zone. The width of the HZ was one of the primary factors affecting the formability of the welded joints, while the tensile strength and ductility of the HZ were secondary factors. FE simulation of the Erichsen cupping test results indicated that the forming strain of the welded joint with narrow HZ concentrated on the BM, while the forming strain of the welded joint with wide HZ concentrated on the HZ. The HZ strain reached the deformation limit first due to its weak ductility; therefore, the welded joint with wide HZ had the worst formability. It was also observed that adopting high-velocity and high-laser power welding could greatly improve the formability of the welded joint as a result of reducing the width of the HZ.
The Thermomechanical Finite Element Analysis of 3003-H14 Plates Joined by the GMAW Process
Authors: Hernández Maribel , Ambriz Ricardo R. , García Christian , Jaramillo David
Published: May 2020

The gas metal arc welding (GMAW) process was used to weld 3003-H14 plates under restricted and unrestricted thermal expansion. Experimental and numerical analysis were conducted to determine the relation between weld thermal cycles and residual stresses. A customized data acquisition system with K-type thermocouples was used to measure the weld thermal cycles, while residual stresses were determined by the hole drilling method. Thermo-mechanical simulation models for the two restricted conditions were implemented from the experimental data obtained. A double ellipse heat distribution geometry was used to model the heat moving source by using the finite element method. Thermal rates and peak temperatures were approximated by the finite element model with 2% difference, with respect to the experimental weld thermal cycles. Longitudinal and transverse normal residual stresses determined by the finite element model showed a good comparison with experimental measurements. The larger residual stresses were in the transverse direction for both clamping conditions, which indicated that working loading paths along the lateral direction of the welded plate are more influenced by the post-welding residual stresses.
Analysis of the Drawing Process of Small-Sized Seam Tubes
Authors: Schrek Alexander , Brusilová Alena , Švec Pavol , Gábrišová Zuzana , Moravec Ján
Published: May 2020

This article is focused on an analysis of factors negatively affecting the tube production process of tubes made from austenitic stainless steel with a very small diameter of ϕ 0.34 mm. The analysis was concentrated on factors that affect the drawing process stability of the seam tubes where the desired final dimensions—a diameter of ϕ 0.34 mm and a wall thickness of 0.057 mm—are limiting factors. Seam tubes made from steel 1.4306 and 1.4301, from producers KT and EW with a longitudinal weld line made by tungsten inert gas (TIG) welding, were used as blanks for constituent drawing operations. It is desirable to provide sufficient inert gas flow and cooling during the formation of a weld joint in a protective atmosphere chamber. A significant temperature gradient prevents the formation of undesirable Cr23C6 carbides in the heat-affected zone (HAZ) which negatively affects the plasticity and formability of the steel and is the cause of technological fractures.
Utilization of Geodetic Methods Results in Small Open-Pit Mine Conditions: A Case Study from Slovakia
Authors: Labant Slavomir , Bindzarova Gergelova Marcela , Kuzevicova Zofia , Kuzevic Stefan , Fedorko Gabriel , Molnar Vieroslav
Published: May 2020

Mining, especially surface mining, has a significant impact on the upper part of the soil cover, including fauna and flora. The article deals with the use of geodetic methods to observe the mining process and its possible impact on the environment. The created model can be used to design the recovery and reclamation of open-pit mines after their closure and mining termination. For the modeling of an open-pit mine, 2151 points from two stages of geodetic measurements were used. Graphical presentations of the geodetic measurements were compared with data from aerial photogrammetry. The measurement and processing results were used to visualize the spatial changes in the open-pit mine, which are necessary to take measures related to the recovery of the landscape affected by mining. Based on the calculation, 145.266 m3 were extracted during the period under exploration. When calculating the average excavated volume per working day, it was found that 188 m3 = 500 tons = 0.5 kilotons per day were extracted between the monitored periods. When comparing the original surface and the generated model of the open-pit mine, it was found that the entire top of the rock massif was permanently removed in the total volume of 3,421,000 m3. To capture the impact of mining on the surrounding environment, multispectral images of Landsat 7 and 8 during the observed period. Focused attention was divided into two factors, land surface temperature, and vegetation condition. The results from the temperature maps show that the open-pit mine is becoming a heat island. Analysis of the vegetative state confirms the rapid change in the health of vegetation, resp. reduction of its condition in the area around the open-pit mine. The presented results show that the selected methods and procedures are applicable in the conditions of the small mining company in Slovakia.
Graphene-Based Strategies in Liquid Biopsy and in Viral Diseases Diagnosis
Authors: Cordaro Annalaura , Neri Giulia , Sciortino Maria Teresa , Scala Angela , Piperno Anna
Published: May 2020

Graphene-based materials are intriguing nanomaterials with applications ranging from nanotechnology-related devices to drug delivery systems and biosensing. Multifunctional graphene platforms were proposed for the detection of several typical biomarkers (i.e., circulating tumor cells, exosomes, circulating nucleic acids, etc.) in liquid biopsy, and numerous methods, including optical, electrochemical, surface-enhanced Raman scattering (SERS), etc., have been developed for their detection. Due to the massive advancements in biology, material chemistry, and analytical technology, it is necessary to review the progress in this field from both medical and chemical sides. Liquid biopsy is considered a revolutionary technique that is opening unexpected perspectives in the early diagnosis and, in therapy monitoring, severe diseases, including cancer, metabolic syndrome, autoimmune, and neurodegenerative disorders. Although nanotechnology based on graphene has been poorly applied for the rapid diagnosis of viral diseases, the extraordinary properties of graphene (i.e., high electronic conductivity, large specific area, and surface functionalization) can be also exploited for the diagnosis of emerging viral diseases, such as the coronavirus disease 2019 (COVID-19). This review aimed to provide a comprehensive and in-depth summarization of the contribution of graphene-based nanomaterials in liquid biopsy, discussing the remaining challenges and the future trend; moreover, the paper gave the first look at the potentiality of graphene in COVID-19 diagnosis.
Pt Nanoparticles with High Oxidase-Like Activity and Reusability for Detection of Ascorbic Acid
Authors: Cheng Qin , Yang Yong , Peng Yusi , Liu Meng
Published: May 2020

Noble metal nanoenzymes such as Pt, Au, Pd, etc. exhibit magnificent activity. However, due to the scarce reserves and expensive prices of precious metals, it is essential to investigate their enzyme-like activity and explore the possibility of their reuse. In this work, the oxidase-like activity and reusability of several Pt nanoparticles with different morphologies were detected. We compared the Pt nanoparticles (NPs) with a size of about 30 nm self-assembled by 5 nm Pt nanoparticles and Pt nanoparticles (Pt-0 HCl) with a diameter of about 5 nm, and found that their Michaelis−Menten constants (Km) were close and their initial performance similar, but the Pt NPs had better reusability. This was probably attributed to the stacked structure of Pt NPs, which was conducive to the substance transport and sufficient contact. At the same time, it was found that the size, dispersion, and organic substances adsorbed on the surface of Pt nanoparticles would have a significant impact on their reusability. A colorimetric detection method was designed using the oxidase-like activity of Pt NPs to detect ascorbic acid in triplicate. The limits of detection were 131 ± 15, 144 ± 14, and 152 ± 9 nM, with little difference. This research not only showed that the morphology of the catalyst could be changed and its catalytic performance could be controlled by a simple liquid phase synthesis method, but also that it had great significance for the reuse of Pt nanoenzymes in the field of bioanalysis.
Comparative Study of the Antimicrobial Effects of Tungsten Nanoparticles and Tungsten Nanocomposite Fibres on Hospital Acquired Bacterial and Viral Pathogens
Authors: Matharu Rupy Kaur , Ciric Lena , Ren Guogang , Edirisinghe Mohan
Published: May 2020

A significant proportion of patients acquire hospital associated infections as a result of care within the NHS each year. Numerous antimicrobial strategies, such as antibiotics and surface modifications to medical facilities and instruments, have been devised in an attempt to reduce the incidence of nosocomial infections, but most have been proven unsuccessful and unsustainable due to antibiotic resistance. Therefore, the need to discover novel materials that can combat pathogenic microorganisms is ongoing. Novel technologies, such as the potential use of nanomaterials and nanocomposites, hold promise for reducing these infections in the fight against antimicrobial resistance. In this study, the antimicrobial activity of tungsten, tungsten carbide and tungsten oxide nanoparticles were tested against Escherichia coli, Staphylococcus aureus and bacteriophage T4 (DNA virus). The most potent nanoparticles, tungsten oxide, were incorporated into polymeric fibres using pressurised gyration and characterised using scanning electron microscopy and energy dispersive X-ray spectroscopy. The antimicrobial activity of tungsten oxide/polymer nanocomposite fibres was also studied. The results suggest the materials in this study promote mediation of the inhibition of microbial growth in suspension.
Preparation and Characterization of Graphene Oxide for Pb(II) and Zn(II) Ions Adsorption from Aqueous Solution: Experimental, Thermodynamic and Kinetic Study
Authors: Guerrero-Fajardo Carlos , Giraldo Liliana , Moreno-Piraján Juan
Published: May 2020

A thermodynamic and kinetic study of the adsorption process of Zn (II) and Pb (II) ions from aqueous solution on the surface of graphene oxide (GO) to establish the mechanisms of adsorbate–adsorbent interaction on this surface. The effect of pH on the retention capacity was studied and adsorption isotherms were determined from aqueous solution of the ions; once the experimental data was obtained, the kinetic and thermodynamic study of the sorption process was carried out. The data were fitted to the Langmuir, Freundlich, Dubinin-Raduskevich and Temkin isotherm models. The results showed that Zn(II) and Pb(II) on the GO adsorbing surface fitted the Langmuir model with correlation coefficients (R2) of 0.996. Kinetic models studied showed that a pseudo-second-order model was followed and thermodynamically, the process was spontaneous according to the values of Gibbs free energy (ΔGo). N2 adsorption isotherms were determined and modeled with the NLDFT (nonlocal density functional theory) and QSDFT (quenched solid density functional theory) kernels.
Propolis as a Potential Disease-Modifying Strategy in Parkinson’s disease: Cardioprotective and Neuroprotective Effects in the 6-OHDA Rat Model
Authors: C. Gonçalves Valeria , J. L. L. Pinheiro Daniel , de la Rosa Tomás , G. de Almeida Antônio-Carlos , A. Scorza Fúlvio , A. Scorza Carla
Published: May 2020

Patients with Parkinson’s disease (PD) manifest nonmotor and motor symptoms. Autonomic cardiovascular dysregulation is a common nonmotor manifestation associated with increased morbimortality. Conventional clinical treatment alleviates motor signs but does not change disease progression and fails in handling nonmotor features. Nutrition is a key modifiable determinant of chronic disease. This study aimed to assess the effects of propolis on cardiological features, heart rate (HR) and heart rate variability (HRV) and on nigrostriatal dopaminergic damage, detected by tyrosine hydroxylase (TH) immunoreactivity, in the 6-hydroxydopamine (6-OHDA) rat model of PD. Male Wistar rats were injected bilaterally with 6-OHDA or saline into the striatum and were treated with propolis or water for 40 days. Autonomic function was assessed by time domain parameters (standard deviation of all normal-to-normal intervals (SDNN) and square root of the mean of the squared differences between adjacent normal RR intervals (RMSSD)) of HRV calculated from electrocardiogram recordings. Reductions in HR (p = 1.47 × 10−19), SDNN (p = 3.42 × 10−10) and RMSSD (p = 8.2 × 10−6) detected in parkinsonian rats were reverted by propolis. Propolis attenuated neuronal loss in the substantia nigra (p = 5.66 × 10−15) and reduced striatal fiber degeneration (p = 7.4 × 10−5) in 6-OHDA-injured rats, which also showed significant weight gain (p = 1.07 × 10−5) in comparison to 6-OHDA-lesioned counterparts. Propolis confers cardioprotection and neuroprotection in the 6-OHDA rat model of PD.
Multiproduct Economic Lot Scheduling Problem with Returns and Sorting Line
Authors: Ferretti Ivan
Published: May 2020

This work studies a hybrid manufacturing–remanufacturing system with a sorting line and disposal. In particular, it models a company that collects used product, remanufactures returned products that have been evaluated as suitable to be recovered, and manufactures new products to satisfy customer demand. Specifically, the system is modeled as a multilevel inventory system, with three types of stock (used products inventory, recoverable inventory, and serviceable inventory), each characterized by an inventory holding cost, and three limited capacity resources: a sorting line, which enables the company to distinguish those returns that are remanufacturable from those that are not; a remanufacturing line to carry out operations on sorted remanufacturable returns; and a manufacturing line to produce new products in order to satisfy customer demand. Each resource is characterized by a setup cost, as well as a constant production rate, while each type of stock is associated with an inventory holding cost. The aim of the paper is to develop a model for the considered production system in order to minimize the setup and inventory holding costs. In particular, the objective is to evaluate the behavior of a controllable disposal rate with the minimization of the total cost function, by considering the effect on the remanufacturing and manufacturing lines.
CURRÍCULO DE LOS AUTORES
Authors: Villalba Doris
Published: May 2020

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Prevalencia de enteroparasitosis en niños que asisten a una Unidad Educativa
Authors: Villca Mamani Milena Ruth
Published: May 2020

Introducción: Los parásitos intestinales son un problema de alta prevalencia entre los niños, especialmente en países en desarrollo, afecta a todas lasedades y sexos, pero se presentan sobre todo en los primeros años de vida. Objetivo: Conocer la frecuencia de parasitosis intestinal en niños de 4 a 9 años,en la Unidad Educativa “Tcnl. Rafael Pabón” de la Comunidad de Tres Ríos en el último trimestre de la gestión 2018. Material y métodos: Investigacióndescriptiva y de campo, población de 36 niños. El examen fue coproparasitológico directo y el método de concentración Ritchie modificado. Resultados: La frecuencia de parasitosis fue de 69%. El 100% de las mismas por protozoarios, siendo los niños de 8 años los más afectados (32%), el género masculino representa el 39% de los casos positivos. Los parásitos que se encontraron con mayor frecuencia son: entamoeba coli y endolimax nana. Conclusiones: La prevalencia de infección por parásitos intestinales en los niños es elevada. De 36 casos, se tiene 25 casos positivos resultando un 69% y 11 casos negativos correspondientes a un 31% de la población. Los niños de 8 años mostraron mayor frecuencia de parasitosis con un porcentaje de 32%.
Teoría y práctica en el desarrollo de las competencias de enfermería en pediatría
Authors: Guía-Yanes Marlin Angélica
Published: May 2020

Introducción: El aprendizaje y la práctica en los profesionales de enfermería en formación debe ser integrativo para el desarrollo de competencias profesionales que le permitan brindar cuidados de enfermería. Objetivo: Analizar la integración teoría y práctica para el desarrollo de competencias profesionales en pediatría. Materiales y métodos: Investigación cuasi-experimental con un diseño de campo prospectivo y transversal. Se aplicó un pre test y post test a los estudiantes de enfermería del quinto semestre basado en la clasificación realizada por Patricia Benner. Resultados: Los estudiantes antes de comenzar las prácticas clínicas se consideran principiantes una vez concluida esta fase son capaces de tomar decisiones y demostrar habilidades y destrezas en el desempeño laboral. Conclusión: Las formulaciones realizadas por Patricia Benner se ajustan hoy en día a la realidad, en la cual debe integrarse el aprendizaje teórico acompañado de la práctica lo que permite desarrollar la formación de competencias pertinentes en el profesional de enfermería para el cumplimiento de los cuidados.
Conocimiento de métodos anticonceptivos en estudiantes adolescentes
Authors: Carpio Ximena Lorena
Published: May 2020

Introducción: La adolescencia según la Organización Mundial de la Salud es el periodo de crecimiento y desarrollo que se produce después de la niñez y antes de la edad adulta, comprende desde los 12 a 19 años de edad. Objetivo: Determinar el nivel de conocimiento acerca de los métodos anticonceptivos que tienen los adolescentes de las Unidades Educativas “Cañaviri y Santiago de Ventilla”. Material y métodos: Se realizó un estudio cuantitativo, descriptiva, observacional y de corte transversal, con una población y muestra constituida por 81 adolescentes de las unidades educativas. Resultados: En relación a los conocimientos demostrados los de clase alta representaba poco porcentaje de la población y contestaron de manera correcta, el gran porcentaje estaba compuesto por adolescente de medianos y bajos recursos, los de recursos medio contestaron en un 41,9% de forma incorrecta mientras que los de bajo recursos contestaron de forma incorrecta en un 17,20%. En cuanto al conocimiento de métodos anticonceptivos por sexo, la población de sexo femenino demostró según los porcentajes poseer más conocimiento acerca del tema. Conclusiones: El nivel de conocimiento de los métodos anticonceptivos es limitado, lo que demuestra que los adolescentes están expuestos a enfermedades de transmisión sexual y a embarazos prematuros.
Petroleum geological investigations in East Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’
Authors: Stemmerik Lars , Clausen Ole R. , Korstgård John , Larsen Michael , Piasecki Stefan , Seidler Lars , Surlyk Finn , Therkelsen Jens
Published: May 2020

The multidisciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). In 1996, the hydrocarbon-related studies focused on the sedimentary basins in East Greenland between latitudes 71°N and 74°N (Fig. 1) where nine field teams worked for six weeks in July and August supported by a Hughes 500 helicopter. Within the framework of the project, additional hydrocarbon-related field studies were undertaken in 1996 in western North Greenland, and ore-geological studies were carried out in much of North Greenland (Kragh et al., 1997; Stemmerik et al., 1997). The 1996 field work in East Greenland concentrated on integrated structural, sedimentological and biostratigraphical studies of the Upper Permian and Mesozoic successions. Two Ph.D. projects focused on the sedimentology of the Lower Triassic Wordie Creek Formation and the diagenesis of the Middle and Upper Jurassic succession. Post-doctorate studies were carried out on the Mesozoic–Tertiary structural development of the basin and the mineralisation of the Upper Permian Ravnefjeld Formation. Three student projects on Lower Triassic and Middle Jurassic ammonite stratigraphy, Upper Permian sedimentology, and fault-associated mineralisation were also included in the work. The most important new results arising from the 1996 field work are: 1) Re-interpretation of the Upper Permian Schuchert Dal Formation as a lowstand turbidite unit within the Ravnefjeld Formation; 2) Recognition of Middle Jurassic deposits and thick lowermost Cretaceous sandstones on Hold with Hope; 3) Interpretation of a full spectrum of scarp-derived coarse-clastic mass movement deposits interbedded with Cretaceous shales on eastern Traill Ø; 4) The presence of a thick sand-rich Cretaceous turbidite succession on eastern Traill Ø; 5) Re-interpretation of the Mesozoic–Cenozoic fault systems on Traill Ø and Geographical Society Ø.
The role of bacteria in degradation of exposed massive sulphides at Citronen Fjord, North Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’
Authors: Langdahl Bjarne R. , Elberling Bo
Published: May 2020

The multidisciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). The Citronen Fjord zinc prospect (Fig. 1) discovered by Platinova A/S in 1993 is by far the largest sulphide occurrence known in North Greenland, and is currently being investigated as a potential exploitable resource. However, the mining and processing of sulphide ores can create serious pollution problems in the surrounding terrestrial and aquatic ecosystems by exposing large amounts of sulphidic material to atmospheric oxygen and ‘attack’ by mineral-oxidising bacteria. At lower latitudes, the slow abiotic oxidation of metal sulphides is known to be significantly accelerated by bacterial attack. A microbiological investigation of the Citronen Fjord zinc deposit was initiated in the summer of 1995 to investigate the role bacteria might play in oxidation of sulphidic material in High Arctic areas. This is a joint project involving the Danish Environmental Research Institute (Department of Arctic Environment) and the University of Aarhus (Department of Microbial Ecology).
Metasedimentary rocks, intrusions and deformation history in the south-east part of the c. 1800 Ma Ketilidian orogen, South Greenland: Project SUPRASYD 1996
Authors: Garde Adam A. , Chadwick Brian , Grocott John , Swager Cees
Published: May 2020

The south-east part of the c. 1800 Ma Ketilidian orogen in South Greenland (Allaart, 1976) is dominated by strongly deformed and variably migmatised metasedimentary rocks known as the ‘Psammite and Pelite Zones’ (Chadwick & Garde, 1996); the sediments were mainly derived from the evolving Julianehåb batholith which dominates the central part of the orogen. The main purpose of the present contribution is to outline the deformational history of the Psammite Zone in the region between Lindenow Fjord and Kangerluluk (Fig. 2), investigated in 1994 and 1996 as part of the SUPRASYD project (Garde & Schønwandt, 1995 and references therein; Chadwick et al., in press). The Lindenow Fjord region has high alpine relief and extensive ice and glacier cover, and the fjords are regularly blocked by sea ice. Early studies of this part of the orogen were by boat reconnaissance (Andrews et al., 1971, 1973); extensive helicopter support in the summers of 1992 and 1994 made access to the inner fjord regions and nunataks possible for the first time.A preliminary geological map covering part of the area between Lindenow Fjord and Kangerluluk was published by Swager et al. (1995). Hamilton et al. (1996) have addressed the timing of sedimentation and deformation in the Psammite Zone by means of precise zircon U-Pb geochronology. However, major problems regarding the correlation of individual deformational events and their relationship with the evolution of the Julianehåb batholith were not resolved until the field work in 1996. The SUPRASYD field party in 1996 (Fig. 1) was based at the telestation of Prins Christian Sund some 50 km south of the working area (Fig. 2). In addition to base camp personnel, helicopter crew and the four authors, the party consisted of five geologists and M.Sc. students studying mafic igneous rocks and their mineralisation in selected areas (Stendal et al., 1997), and a geologist investigating rust zones and areas with known gold anomalies.
A review of Greenland activities, 1997
Authors: Ghisler Martin
Published: May 2020

This is the second volume of Review of Greenland activities. It follows the tradition of Report of activities of the former Geological Survey of Greenland that was issued for 30 years until 1996.The bulletin contains 24 articles, introduced by the Director's review for 1997, followed by a list of publications on Greenland issued in the Survey's own series and those scientific papers written by its staff published in international outlets.

The articles report on onshore and offshore field work and on the main Greenland projects carried out during 1997. Several current research reviews are also included. A wide range of topics is touched on from geological and geophysical data on early Archaean to Quaternary rocks, to offshore geophysics and oceanography, with several papers dealing with petroleum and mineral exploration.
Seismic investigations offshore South-East Greenland
Authors: Hopper John R. , Lizarralde Dan , Larsen Hans Christian
Published: May 2020

A high-resolution, shallow-seismic survey off the SouthEast Greenland coast was carried out during August and September 1997 aboard the R/V Dana of the Danish Ministry of Agriculture and Fisheries. This seismic survey supports two large ongoing regional research projects. The Danish Lithosphere Centre (DLC) is involved in a number of investigations to understand the tectonic evolution of the North Atlantic region since the early Tertiary, and a consortium of scientists from the Geological Survey of Denmark and Greenland (GEUS) and the Free University of Amsterdam (VU) are engaged in palaeo-oceanographic studies of climate change since the Neogene. The survey was thus a cooperative venture where ship time was shared between the participating research institutes. This report focuses on the DLC component of the cruise, which primarily involved the acquisition of site-survey data to be used in the planning and execution of drilling operations scheduled for 1998. These drilling operations are aimed at understanding the voluminous volcanic activity that accompanied continental rifting and the formation of the South-East Greenland margin. The GEUS/VU component of the cruise is summarised elsewhere in this volume (Kuijpers et al. 1998, this volume).
Proterozoic thermal activity in the Archaean basement of the Disko Bugt region and eastern Nuussuaq, West Greenland: evidence from K-Ar and 40Ar-39Ar mineral age investigations
Authors: Rasmussen Henrik , Holm Paul Martin
Published: May 2020

K-Ar and 40Ar-39Ar analyses of amphiboles from Archaean amphibolites and gneisses show that Proterozoic tectono-thermal activity has played an important role in the metamorphic and structural development of the Precambrian rocks around north-eastern Disko Bugt and in eastern Nuussuaq. Proterozoic thermal activity lead to resetting of the K-Ar ages of amphiboles in eastern Nuussuaq, resulting in ages of c. 1750 to 1925 Ma; in the Disko Bugt area the effects are seen in total or partial resetting with K-Ar ages scattering mostly between 2750 and 1870 Ma. Resetting is caused either by total diffusion of earlier accumulated radiogenic argon or by complete recrystallisation of the amphiboles. Archaean 40Ar-39Ar ages obtained from maﬁc xenoliths within the Atâ tonalite show that not all parts of the area suffered argon loss during Proterozoic reheating. Incorporation of signiﬁcant proportions of excess argon in some amphiboles is seen from 40Ar-39Ar mineral age spectra obtained for samples from supracrustal rocks and from maﬁc xenoliths in the Atâ tonalite. Phlogopite phenocrysts from a lamproite stock yielded a K-Ar age of 1764 ± 24 Ma, identical to a previously determined K-Ar age of the matrix phlogopite. These ages probably date the emplacement of the lamproite, and mark the time after which no tectono-thermal events affected the area.