bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Diversity and Dynamics of Human Three-Finger Proteins Acting on Nicotinic Acetylcholine Receptors
Authors: Paramonov Alexander S. , Kocharovskaya Milita V. , Tsarev Andrey V. , Kulbatskii Dmitrii S. , Loktyushov Eugene V. , Shulepko Mikhail A. , Kirpichnikov Mikhail P. , Lyukmanova Ekaterina N. , Shenkarev Zakhar O.
Published: October 2020

Ly-6/uPAR or three-finger proteins (TFPs) contain a disulfide-stabilized β-structural core and three protruding loops (fingers). In mammals, TFPs have been found in epithelium and the nervous, endocrine, reproductive, and immune systems. Here, using heteronuclear NMR, we determined the three-dimensional (3D) structure and backbone dynamics of the epithelial secreted protein SLURP-1 and soluble domains of GPI-anchored TFPs from the brain (Lynx2, Lypd6, Lypd6b) acting on nicotinic acetylcholine receptors (nAChRs). Results were compared with the data about human TFPs Lynx1 and SLURP-2 and snake α-neurotoxins WTX and NTII. Two different topologies of the β-structure were revealed: one large antiparallel β-sheet in Lypd6 and Lypd6b, and two β-sheets in other proteins. α-Helical segments were found in the loops I/III of Lynx2, Lypd6, and Lypd6b. Differences in the surface distribution of charged and hydrophobic groups indicated significant differences in a mode of TFPs/nAChR interactions. TFPs showed significant conformational plasticity: the loops were highly mobile at picosecond-nanosecond timescale, while the β-structural regions demonstrated microsecond-millisecond motions. SLURP-1 had the largest plasticity and characterized by the unordered loops II/III and cis-trans isomerization of the Tyr39-Pro40 bond. In conclusion, plasticity could be an important feature of TFPs adapting their structures for optimal interaction with the different conformational states of nAChRs.
Evaluation of Hyaluronic Acid to Modulate Oral Squamous Cell Carcinoma Growth In Vitro
Authors: Ringer Jordan , Morrison Bryan , Kingsley Karl
Published: October 2020

Introduction: Previous studies have demonstrated that glycosaminoglycan hyaluronic acid (HA) is capable of mediating oral tumor growth. Some clinical evidence has suggested reduced HA expression predicts poor cancer prognosis and that HA-chemotherapy conjugates may function synergistically to inhibit oral tumor growth. Other studies have found conflicting results that suggest enhanced CD44-HA-mediated growth and proliferation. Due to the lack of clarity regarding HA function, the primary goal of this study was to investigate the effects of HA using well-characterized oral cancer cell lines. Methods: Using several commercially available oral squamous cell carcinoma lines (and a normal non-cancerous control), 96-well growth and viability assays were conducted using HA (alone and in combination with chemotherapeutic agents paclitaxel and PD98059). Results: Different results were observed in each of the cell lines evaluated. HA induced small, non-significant changes in cellular viability among each of the cell lines within a narrow range (1–8%), p = 0.207. However, HA induced differing effects on growth, with minimal, non-significant changes among some cell lines, such as SCC4 (+1.7%), CCL-30 (−2.8%), and SCC15 (−2.5%), p = 0.211 and more robust inhibition among other cell lines, SCC9 (−24.4%), SCC25 (−36.6%), and CAL27 (−47.8%), p = 0.0001. Differing effects were also observed with growth and viability under concomitant administration of HA with PD98059 or paclitaxel. Further analysis of these data revealed strong inverse (Pearson’s) correlations between initial baseline growth rate and responsiveness to HA administration, ranging from R = −0.27 to R = −0.883. Conclusion: The results of this study revealed differing responses to HA, which may be inversely correlated with intrinsic characteristics, such as the baseline growth rate. This may suggest that the more rapidly growing cell lines are more responsive to combination therapy with hyaluronic acid; an important finding that may provide insights into the mechanisms responsible for these observations.
Zn- or Cu-containing CaP-Based Coatings Formed by Micro-Arc Oxidation on Titanium and Ti-40Nb Alloy: Part II—Wettability and Biological Performance
Authors: Komarova Ekaterina G. , Sharkeev Yurii P. , Sedelnikova Mariya B. , Prymak Oleg , Epple Matthias , Litvinova Larisa S. , Shupletsova Valeria V. , Malashchenko Vladimir V. , Yurova Kristina A. , Dzyuman Anna N. , Kulagina Irina V. , Mushtovatova Lyudmila S. , Bochkareva Olga P. , Karpova Mariia R. , Khlusov Igor A.
Published: October 2020

This work describes the wettability and biological performance of Zn- and Cu-containing CaP-based coatings prepared by micro-arc oxidation on pure titanium (Ti) and novel Ti-40Nb alloy. Good hydrophilic properties of all the coatings were demonstrated by the low contact angles with liquids, not exceeding 45°. An increase in the applied voltage led to an increase of the coating roughness and porosity, thereby reducing the contact angles to 6° with water and to 17° with glycerol. The free surface energy of 75 ± 3 mJ/m2 for all the coatings were determined. Polar component was calculated as the main component of surface energy, caused by the presence of strong polar PO43− and OH− bonds. In vitro studies showed that low Cu and Zn amounts (~0.4 at.%) in the coatings promoted high motility of human adipose-derived multipotent mesenchymal stromal cells (hAMMSC) on the implant/cell interface and subsequent cell ability to differentiate into osteoblasts. In vivo study demonstrated 100% ectopic bone formation only on the surface of the CaP coating on Ti. The Zn- and Cu-containing CaP coatings on both substrates and the CaP coating on the Ti-40Nb alloy slightly decreased the incidence of ectopic osteogenesis down to 67%. The MAO coatings showed antibacterial efficacy against Staphylococcus aureus and can be arranged as follows: Zn-CaP/Ti > Cu-CaP/TiNb, Zn-CaP/TiNb > Cu-CaP/Ti.
Effect of Hot Isostatic Pressing on Porosity and Mechanical Properties of 316 L Stainless Steel Prepared by the Selective Laser Melting Method
Authors: Cegan Tomas , Pagac Marek , Jurica Jan , Skotnicova Katerina , Hajnys Jiri , Horsak Lukas , Soucek Kamil , Krpec Pavel
Published: October 2020

The manufacturing route primarily determines the properties of materials prepared by additive manufacturing methods. In this work, the microstructural features and mechanical properties of 316 L stainless steel prepared by the selective laser method have been determined. Three types of samples, (i) selective laser melted (SLM), (ii) selective laser melted and hot isostatic pressed (HIP) and (iii) selective laser melted and heat treated (HT), were characterized. Microstructural analysis revealed that SLM samples were formed by melt pool boundaries with fine cellular–dendritic-type microstructure. This type of microstructure disappeared after HT or HIP and material were formed by larger grains and sharply defined grain boundaries. The SLM-prepared samples contained different levels of porosity depending on the preparation conditions. The open interconnected LOF (lack of fusion) pores were observed in the samples, which were prepared with using of scanning speed 1200 mm/s. The blowhole and keyhole type of porosity were observed in the samples prepared by lower scanning speeds. The HIP caused a significant decrease in internal closed porosity to 0.1%, and a higher pressure of 190 MPa was more effective than the usually used pressure of 140 MPa, but for samples with open porosity, HIP was not effective. The relatively high yield strength of 570 MPa, tensile strength of 650 MPa and low ductility of 30–34% were determined for SLM samples with the lower porosity content than 1.3%. The samples after HIP showed lower yield strengths than after SLM (from 290 to 325 MPa) and relatively high ductility of 47.8–48.5%, regardless of the used SLM conditions.
Measurement Modulus of Elasticity Related to the Atomic Density of Planes in Unit Cell of Crystal Lattices
Authors: Rabiei Marzieh , Palevicius Arvydas , Dashti Amir , Nasiri Sohrab , Monshi Ahmad , Vilkauskas Andrius , Janusas Giedrius
Published: October 2020

Young’s modulus (E) is one of the most important parameters in the mechanical properties of solid materials. Young’s modulus is proportional to the stress and strain values. There are several experimental and theoretical methods for gaining Young’s modulus values, such as stress–strain curves in compression and tensile tests, electromagnetic-acoustic resonance, ultrasonic pulse echo and density functional theory (DFT) in different basis sets. Apparently, preparing specimens for measuring Young’s modulus through the experimental methods is not convenient and it is time-consuming. In addition, for calculating Young’s modulus values by software, presumptions of data and structures are needed. Therefore, this new method for gaining the Young’s modulus values of crystalline materials is presented. Herein, the new method for calculating Young’s modulus of crystalline materials is extracted by X-ray diffraction. In this study, Young’s modulus values were gained through the arbitrary planes such as random (hkl) in the research. In this study, calculation of Young’s modulus through the relationship between elastic compliances, geometry of the crystal lattice and the planar density of each plane is obtained by X-ray diffraction. Sodium chloride (NaCl) with crystal lattices of FCC was selected as the example. The X-ray diffraction, elastic stiffness constant and elastic compliances values have been chosen by the X’Pert software, literature and experimental measurements, respectively. The elastic stiffness constant and Young’s modulus of NaCl were measured by the ultrasonic technique and, finally, the results were in good agreement with the new method of this study. The aim of the modified Williamson–Hall (W–H) method in the uniform stress deformation model (USDM) utilized in this paper is to provide a new approach of using the W–H equation, so that a least squares technique can be applied to minimize the sources of errors.
An In Vitro Study on the Antimicrobial Properties of Essential Oil Modified Resin Composite against Oral Pathogens
Authors: Lapinska Barbara , Szram Aleksandra , Zarzycka Beata , Grzegorczyk Janina , Hardan Louis , Sokolowski Jerzy , Lukomska-Szymanska Monika
Published: October 2020

Modifying the composition of dental restorative materials with antimicrobial agents might induce their antibacterial potential against cariogenic bacteria, e.g., S.mutans and L.acidophilus, as well as antifungal effect on C.albicans that are major oral pathogens. Essential oils (EOs) are widely known for antimicrobial activity and are successfully used in dental industry. The study aimed at evaluating antibacterial and antifungal activity of EOs and composite resin material (CR) modified with EO against oral pathogens. Ten EOs (i.e., anise, cinnamon, citronella, clove, geranium, lavender, limette, mint, rosemary thyme) were tested using agar diffusion method. Cinnamon and thyme EOs showed significantly highest antibacterial activity against S.mutans and L.acidophilus among all tested EOs. Anise and limette EOs showed no antibacterial activity against S.mutans. All tested EOs exhibited antifungal activity against C.albicans, whereas cinnamon EO showed significantly highest and limette EO significantly lowest activity. Next, 1, 2 or 5 µL of cinnamon EO was introduced into 2 g of CR and microbiologically tested. The modified CR showed higher antimicrobial activity in comparison to unmodified one. CR containing 2 µL of EO showed the best antimicrobial properties against S.mutans and C.albicans, while CR modified with 1 µL of EO showed the best antimicrobial properties against L.acidophilus.
Preparation of Photoactive Transition-Metal Layered Double Hydroxides (LDH) to Replace Dye-Sensitized Materials in Solar Cells
Authors: Naseem Sajid , Gevers Bianca R. , Labuschagné Frederick J. W. J. , Leuteritz Andreas
Published: October 2020

This work highlights the use of Fe-modified MgAl-layered double hydroxides (LDHs) to replace dye and semiconductor complexes in dye-sensitized solar cells (DSSCs), forming a layered double hydroxide solar cell (LDHSC). For this purpose, a MgAl-LDH and a Fe-modified MgAl LDH were prepared. X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy were used to analyze the structural properties, morphology, and success of the Fe-modification of the synthesized LDHs. Ultraviolet-visible (UV-Vis) absorption spectroscopy was used to analyze the photoactive behavior of these LDHs and compare it to that of TiO2 and dye-sensitized TiO2. Current-voltage (I–V) solar simulation was used to determine the fill factor (FF), open circuit voltage (VOC), short circuit current (ISC), and efficiency of the LDHSCs. It was shown that the MgFeAl-LDH can act as a simultaneous photoabsorber and charge separator, effectively replacing the dye and semiconductor complex in DSSCs and yielding an efficiency of 1.56%.
Synthesis, Characterization and Use of Mesoporous Silicas of the Following Types SBA-1, SBA-2, HMM-1 and HMM-2
Authors: Jarmolińska Sylwia , Feliczak-Guzik Agnieszka , Nowak Izabela
Published: October 2020

Mesoporous silicas have enjoyed great interest among scientists practically from the moment of their discovery thanks to their unique attractive properties. Many types of mesoporous silicas have been described in literature, the most thoroughly MCM-41 and SBA-15 ones. The focus of this review are the methods of syntheses, characterization and use of mesoporous silicas from SBA (Santa Barbara Amorphous) and HMM (Hybrid Mesoporous Materials) groups. The first group is represented by (i) SBA-1 of three-dimensional cubic structure and Pm3¯n symmetry and (ii) SBA-2 of three-dimensional combined hexagonal and cubic structures and P63/mmc symmetry. The HMM group is represented by (i) HMM-1 of two-dimensional hexagonal structure and p6mm symmetry and (ii) HMM-2 of three-dimensional structure and P63/mmc symmetry. The paper provides comprehensive information on the above-mentioned silica materials available so far, also including the data for the silicas modified with metal ions or/and organic functional groups and examples of the materials applications.
Scale-Dependent Dielectric Properties in BaZr0.05Ti0.95O3 Ceramics
Authors: Padurariu Leontin , Lukacs Vlad-Alexandru , Stoian George , Lupu Nicoleta , Curecheriu Lavinia Petronela
Published: October 2020

In the present work, BaZr0.05Ti0.95O3 ceramics with grain sizes between 0.45 and 135 µm were prepared by solid-state reaction and classical sintering. The effect of grain size on dielectric properties was systematically explored, and it was found that dielectric permittivity reaches a maximum value for grain sizes between 1.5 and 10 µm and then rapidly drops for larger grain sizes. A numerical finite element method was employed to eliminate the effect of porosity on the effective values of permittivity. The results indicate that it is possible to have a critical size in slightly doped barium titanate ceramics with enhanced functional properties for a grain size between 1.5 and 10 µm.
Estimation in Partial Functional Linear Spatial Autoregressive Model
Authors: Hu Yuping , Wu Siyu , Feng Sanying , Jin Junliang
Published: October 2020

Functional regression allows for a scalar response to be dependent on a functional predictor; however, not much work has been done when response variables are dependence spatial variables. In this paper, we introduce a new partial functional linear spatial autoregressive model which explores the relationship between a scalar dependence spatial response variable and explanatory variables containing both multiple real-valued scalar variables and a function-valued random variable. By means of functional principal components analysis and the instrumental variable estimation method, we obtain the estimators of the parametric component and slope function of the model. Under some regularity conditions, we establish the asymptotic normality for the parametric component and the convergence rate for slope function. At last, we illustrate the finite sample performance of our proposed methods with some simulation studies.
Epidemiology and Toxicology of Ciguatera Poisoning in the Colombian Caribbean
Authors: Navarro Quiroz Roberto , Herrera-Usuga Juan Carlos , Osorio-Ospina Laura Maria , Garcia-Pertuz Katia Margarita , Navarro Quiroz Elkin
Published: October 2020

Ciguatera is a food intoxication caused by the consumption of primarily coral fish; these species exist in large numbers in the seas that surround the Colombian territory. The underreported diagnosis of this clinical entity has been widely highlighted due to multiple factors, such as, among others, ignorance by the primary care practitioner consulted for this condition as well as clinical similarity to secondary gastroenteric symptoms and common food poisonings of bacterial, parasitic or viral etiology. Eventually, it was found that people affected by ciguatoxins had trips to coastal areas hours before the onset of symptoms. Thanks to multiple studies over the years, it has been possible to identify the relation between toxigenic dinoflagellates and seagrasses, as well as its incorporation into the food chain, starting by fish primarily inhabiting reef ecosystems and culminating in the intake of these by humans. Identifying the epidemiological link, its cardinal symptoms and affected systems, such as gastrointestinal, the peripheral nervous system and, fortunately with a low frequency, the cardiovascular system, leads to a purely clinical diagnostic impression without necessitating further complementary studies; in addition, what would also help fight ciguatera poisoning is performing an adequate treatment of the symptoms right from the start, without underestimating or overlooking any associated complications.
Depression, Metabolic Syndrome, Serum TSH, and Vitamin D Concentrations in Rural and Urban Postmenopausal Women
Authors: Bojar Iwona , Raczkiewicz Dorota , Sarecka-Hujar Beata
Published: October 2020

Background and objectives: Depression is a serious problem affecting people worldwide, however it more commonly concerns women. Depression reduces the quality of life and, in many cases, leads to suicide. Numerous new biological factors have been demonstrated to have an impact on the pathogenesis of depression, including vitamin D, thyroid hormones, as well as factors related to heart disease. The aim of the study was to assess the impact of serum thyroid stimulating hormone (TSH) and vitamin D concentrations as well as metabolic syndrome on the severity of depression in Polish postmenopausal women from urban and rural areas. Materials and Methods: The study was conducted in 2018–2019 in the Lublin region, Poland, and comprised 396 postmenopausal women (239 living in rural areas and 157 living in urban areas). Metabolic syndrome criteria according to the International Diabetes Federation and Beck Depression Inventory were used, and laboratory blood tests were performed. Results: A significantly higher percentage of the examined rural residents had moderate or severe depression in comparison to the urban ones (p = 0.049). The examined women from rural areas had a significantly higher serum vitamin D concentration in comparison to the urban ones (p < 0.001). The rural residents more commonly had below-normal levels of serum TSH and less commonly had normal levels in comparison to the urban residents. Metabolic syndrome was found in 70% of the rural residents, and that number was significantly lower in the urban ones (22%, p < 0.001). Conclusions: The severity of depression in postmenopausal Polish women was correlated negatively with the serum TSH concentration in women from rural areas. The severity of depression was increased in urban postmenopausal women with hypertension. No correlation of the depression severity with the serum vitamin D concentration or other criteria of metabolic syndrome was found.
Lipotransfer Strategies and Techniques to Achieve Successful Breast Reconstruction in the Radiated Breast
Authors: Crawford Kristina , Endara Matthew
Published: October 2020

Radiation therapy is frequently a critical component of breast cancer care but carries with it side effects that are particularly damaging to reconstructive efforts. Autologous lipotransfer has the ability to improve radiated skin throughout the body due to the pluripotent stem cells and multiple growth factors transferred therein. The oncologic safety of lipotransfer to the breasts is demonstrated in the literature and is frequently considered an adjunctive procedure for improving the aesthetic outcomes of breast reconstruction. Using lipotransfer as an integral rather than adjunctive step in the reconstructive process for breast cancer patients requiring radiation results in improved complication rates equivalent to those of nonradiated breasts, expanding options in these otherwise complicated cases. Herein, we provide a detailed review of the cellular toxicity conferred by radiotherapy and describe at length our approach to autologous lipotransfer in radiated breasts.
Photoluminescence Imaging of Whole Zircon Grains on a Petrographic Microscope—An Underused Aide for Geochronologic Studies
Authors: McAleer Ryan , Jubb Aaron , Hackley Paul , Walsh Gregory , Merschat Arthur , Regan Sean , Burton William , Vazquez Jorge
Published: October 2020

The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most geochronologic information is limited by our inability to predict internal zonation from observations of whole grains. Here we document the use of a petrographic microscope to observe and image the photoluminescence (PL) response of whole zircon grains excited under ultraviolet (UV) light, and the utility of this PL response in selecting grains for geochronology. While zircon fluorescence has long been known, there is limited documentation of its utility for and application to geochronologic studies. Our observations of zircon from an un-metamorphosed igneous rock, two meta-igneous rocks, and a placer deposit show that variations in the PL color are readily observable in real-time, both among grains in a population of zircons and within single grains. Analyses of cross-sections of the same grains demonstrate that the changes in PL correlate with zoning in backscattered electron (BSE) and cathodoluminescence (CL) images as well as with changes in U + Th concentration and spectroscopic proxies for radiation damage. In other words, the whole grain PL provides a low-resolution preview of the U + Th zoning expected in a cross-sectioned grain. We demonstrate the usefulness of this “preview” in identifying and selecting the subset of zircon grains in a heavy mineral separate that has metamorphic rims of sufficient width to date by secondary ionization mass spectrometry (SIMS). The data are also used to place preliminary constraints on the age and U + Th concentrations at which a yellow PL response is observed in natural samples. The PL response of zircon is well-known among spectroscopists, and these simple applications demonstrate several ways in which the response might be more effectively used by geochronologists.
Ultrasound-Assisted Extraction Optimization of α-Glucosidase Inhibitors from Ceratophyllum demersum L. and Identification of Phytochemical Profiling by HPLC-QTOF-MS/MS
Authors: Li Zhen , Tu Zongcai , Wang Hui , Zhang Lu
Published: October 2020

Ceratophyllum demersum L. (CDL) is a traditional Chinese herb to treat many diseases, but research on its anti-diabetic activity is not available. In this research, the α-glucosidase inhibitory ability and phytochemical constituents of CDL extract were firstly studied. Optimal ultrasound-assisted extraction conditions for α-glucosidase inhibitors (AGIs) were optimized by single factor experiment and response surface methodology (RSM), which was confirmed as 70% methanol, liquid-to-solid ratio of 43 (mL/g), extraction time of 54 min, ultrasonic power of 350 W, and extraction temperature of 40 °C. The lowest IC50 value for α-glucosidase inhibition was 0.15 mg dried material/mL (mg DM/mL), which was much lower than that of acarbose (IC50 value of 0.64 mg DM/mL). In total, 80 compounds including 8 organic acids, 11 phenolic acids, 25 flavonoids, 21 fatty acids, and 15 others were identified or tentatively identified from CDL extract by HPLC-QTOF-MS/MS analysis. The results suggested that CDL could be a potential source of α-glucosidase inhibitors. It can also provide useful phytochemical information for research into other bioactivities.
DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers
Authors: Qu Hong-jie , Yuan Lang , Jia Cai-xin , Yu Hai-tao , Xu Hui
Published: October 2020

Understanding the hydrogen atom abstraction (HAA) reactions of N-heterocyclic carbene (NHC)-boranes is essential for extending the practical applications of boron chemistry. In this study, density functional theory (DFT) computations were performed for the HAA reactions of a series of NHC-boranes attacked by •CH2CN, Me• and Et• radicals. Using the computed data, we investigated the correlations of the activation and free energy barriers with their components, including the intrinsic barrier, the thermal contribution of the thermodynamic reaction energy to the kinetic barriers, the activation Gibbs free energy correction and the activation zero-point vibrational energy correction. Furthermore, to describe the dependence of the activation and free energy barriers on the thermodynamic reaction energy or reaction Gibbs free energy, we used a three-variable linear model, which was demonstrated to be more precise than the two-variable Evans–Polanyi linear free energy model and more succinct than the three-variable Marcus-theory-based nonlinear HAA model. The present work provides not only a more thorough understanding of the compositions of the barriers to the HAA reactions of NHC-boranes and the HAA reactivities of the substrates but also fresh insights into the suitability of various models for describing the relationships between the kinetic and thermodynamic physical quantities.
Two New Indole Alkaloids from Toad Venom of Bufo bufo gargarizans
Authors: Chen Yu-Lin , Dai Ying-Hui , Wang An-Dong , Zhou Zi-Ying , Lei Miao , Liu Jiao , Lin Bin , Xia Ming-Yu , Wang Dong
Published: October 2020

Two new indole alkaloids, Bufotenidine B (2) and Bufocarboline A (6), along with seven known indole alkaloids (1, 3–5, and 7–9) and three organic acids (10–12), were isolated from the water extract of toad venom. The structures of the new alkaloids were elucidated by extensive spectroscopic methods. The absolute configurations of 4, 6, and 8 were determined for the first time by electronic circular dichroism (ECD) calculations. The cytotoxic activity of all compounds was tested against human malignant melanoma cells A375 by the MTT method, and no antitumor activity was observed.
The Nutritional and Health Effects of the COVID-19 Pandemic on Patients with Diabetes Mellitus
Authors: Grabia Monika , Markiewicz-Żukowska Renata , Puścion-Jakubik Anna , Bielecka Joanna , Nowakowski Patryk , Gromkowska-Kępka Krystyna , Mielcarek Konrad , Socha Katarzyna
Published: October 2020

COVID-19 related restrictions aimed at curbing the spread of the coronavirus result in changes in daily routines and physical activity which can have a negative effect on eating and health habits. The aim of the study was to assess the impact of the COVID-19 pandemic on patients with diabetes and their nutrition and health behaviours. A survey conducted in July 2020 included 124 individuals with type 1 (n = 90) and 2 (n = 34) diabetes mellitus from Poland. To assess nutritional and health behaviours, an online questionnaire covering basic information, anthropometric data, and details regarding physical activity, eating, and hygiene habits was used. Almost 40% of all respondents with type 1 and 2 diabetes mellitus (DM) stated that their disease self-management had significantly improved. Over 60% of all participants declared that they had started eating more nutritious and regular meals during the COVID-19 pandemic. Enhanced hygiene, in particular, during the period, a statistically significant increase in hand sanitiser use was reported by respondents (18% vs. 82%, p < 0.001). The study demonstrated that the pandemic had a significant impact on the behaviour of patients with DM. Improved disease self-management and making healthy, informed food and hygiene choices were observed.
Injectability of Thermosensitive, Low-Concentrated Chitosan Colloids as Flow Phenomenon through the Capillary under High Shear Rate Conditions
Authors: Rył Anna , Owczarz Piotr
Published: October 2020

Low-concentrated colloidal chitosan systems undergoing a thermally induced sol–gel phase transition are willingly studied due to their potential use as minimally invasive injectable scaffolds. Nevertheless, instrumental injectability tests to determine their clinical utility are rarely performed. The aim of this work was to analyze the flow phenomenon of thermosensitive chitosan systems with the addition of disodium β-glycerophosphate through hypodermic needles. Injectability tests were performed using a texture analyzer and hypodermic needles in the sizes 14G–25G. The rheological properties were determined by the flow curve, three-interval thixotropy test (3ITT), and Cox–Merz rule. It was found that reducing the needle diameter and increasing its length and the crosshead speed increased the injection forces. It was claimed that under the considered flow conditions, there was no need to take into account the viscoelastic properties of the medium, and the model used to predict the injection force, based solely on the shear-thinning nature of the experimental material, showed very good agreement with the experimental data in the shear rate range of 200–55,000 s−1. It was observed that the increase in the shear rate value led to macroscopic structural changes of the chitosan sol caused by the disentangling and ordering of the polysaccharide chains along the shear field.
Multi-Sacrificial Bonds Enhanced Double Network Hydrogel with High Toughness, Resilience, Damping, and Notch-Insensitivity
Authors: Sun Manxi , Qiu Jianhui , Lu Chunyin , Jin Shuping , Zhang Guohong , Sakai Eiichi
Published: October 2020

The engineering applications of hydrogels are generally limited by the common problem of their softness and brittlness. In this study, a composite double network ionic hydrogel (CDN-gel) was obtained by the facile visible light triggered polymerization of acrylic acid (AA), polyvinyl alcohol (PVA), and hydrolyzed triethoxyvinylsilane (TEVS) and subsequent salt impregnation. The resulting CDN-gels exhibited high toughness, recovery ability, and notch-insensitivity. The tensile strength, fracture elongation, Young’s modulus, and toughness of the CDN-gels reached up to ~21 MPa, ~700%, ~3.5 MPa, and ~48 M/m3, respectively. The residual strain at a strain of 200% was only ~25% after stretch-release of 1000 cycles. These properties will enable greater application of these hydrogel materials, especially for the fatigue resistance of tough hydrogels, as well as broaden their applications in damping.
Micellar Organocatalysis Using Smart Polymer Supports: Influence of Thermoresponsive Self-Assembly on Catalytic Activity
Authors: Yu Xiaoqian , Herberg Artjom , Kuckling Dirk
Published: October 2020

Micellar catalysts with a switchable core are attractive materials in organic synthesis. However, little is known about the role of the shell forming block on the performance of the catalyst. Thermoresponsive block copolymers based on poly(N-isopropylacrylamide-co-vinyl-4,4-dimethylazlactone) attached to different permanently hydrophilic blocks, namely poly(ethylene glycol), poly(N,N-dimethylacrylamide), and poly(2,3-dihydroxypropyl acrylate), were successfully synthesized via reversible addition/fragmentation chain transfer radical polymerization (RAFT). Post-polymerization attachment of an amino-functionalized L-prolineamide using the azlactone ring-opening reaction afforded functionalized thermoresponsive block copolymers. Temperature-induced aggregation of the functionalized block copolymers was studied using dynamic light scattering. It was shown that the chemical structure of the permanently hydrophilic block significantly affected the size of the polymer self-assemblies. The functionalized block copolymers were subjected to an aldol reaction between p-nitrobenzaldehyde and cyclohexanone in water. Upon temperature-induced aggregation, an increase in conversion was observed. The enantioselectivity of the polymer-bound organocatalyst improved with an increasing hydrophilic/hydrophobic interface as a result of the different stability of the polymer aggregates.
Basic Research for Additive Manufacturing of Rubber
Authors: Drossel Welf-Guntram , Ihlemann Jörn , Landgraf Ralf , Oelsch Erik , Schmidt Marek
Published: October 2020

The dissemination and use of additive processes are growing rapidly. Nevertheless, for the material class of elastomers made of vulcanizable rubber, there is still no technical solution for producing them using 3D printing. Therefore, this paper deals with the basic investigations to develop an approach for rubber printing. For this purpose, a fused deposition modeling (FDM) 3D printer is modified with a screw extruder. Tests are carried out to identify the optimal printing parameters. Afterwards, test prints are performed for the deposition of rubber strands on top of each other and for the fabrication of simple two-dimensional geometries. The material behavior during printing, the printing quality as well as occurrences of deviations in the geometries are evaluated. The results show that the realization of 3D rubber printing is possible. However, there is still a need for research to stabilize the layers during the printing process. Additionally, further studies are necessary to determine the optimum parameters for traverse speed and material discharge, especially on contours.
Open-Ended and Closed-Ended Measures of Religious/Spiritual Struggles: A Mixed-Methods Study
Authors: Wilt Joshua A. , Takahashi Joyce T. , Jeong Peter , Exline Julie J. , Pargament Kenneth I.
Published: October 2020

Religious and spiritual struggles are typically assessed by self-report scales using closed-ended items, yet nascent research suggests that using open-ended interviews and prompts may complement and advance assessment and theories. In the current mixed-methods study, undergraduate participants (N = 976) completed open-ended descriptions of their religious and spiritual struggles, the Religious and Spiritual Struggles Scale (RSS), and a quantitative measure of religious belief salience. Qualitative description showed that the themes emerging from open-ended descriptions generally fell within the broad domains of the RSS though some descriptions reflected more contextualized struggles. Scores derived from the open-ended responses to assess RSS domains achieved evidence of reliability, and quantitative correlational analyses provided support for convergent and discriminant validity with the RSS. Correlations revealed a mix of similar and divergent associations between methods of assessing religious and spiritual struggles and religious belief salience. Open-ended descriptions of religious and spiritual struggles may yield reliable and valid information that is related to but distinct from assessments relying on closed-ended items.
3D-Printed Sensors and Actuators in Cell Culture and Tissue Engineering: Framework and Research Challenges
Authors: Pérez Pablo , Serrano Juan Alfonso , Olmo Alberto
Published: October 2020

Three-dimensional printing technologies have been recently proposed to monitor cell cultures and implement cell bioreactors for different biological applications. In tissue engineering, the control of tissue formation is crucial to form tissue constructs of clinical relevance, and 3D printing technologies can also play an important role for this purpose. In this work, we study 3D-printed sensors that have been recently used in cell culture and tissue engineering applications in biological laboratories, with a special focus on the technique of electrical impedance spectroscopy. Furthermore, we study new 3D-printed actuators used for the stimulation of stem cells cultures, which is of high importance in the process of tissue formation and regenerative medicine. Key challenges and open issues, such as the use of 3D printing techniques in implantable devices for regenerative medicine, are also discussed.
Exploring the Limitations of Event-Related Potential Measures in Moving Subjects: Pilot Studies of Four Different Technical Modifications in Ergometer Rowing
Authors: Hill Holger
Published: October 2020

Measuring brain activity in moving subjects is of great importance for investigating human behavior in ecological settings. For this purpose, EEG measures are applicable; however, technical modifications are required to reduce the typical massive movement artefacts. Four different approaches to measure EEG/ERPs during rowing were tested: (i) a purpose-built head-mounted preamplifier, (ii) a laboratory system with active electrodes, and a wireless headset combined with (iii) passive or (iv) active electrodes. A standard visual oddball task revealed very similar (within subjects) visual evoked potentials for rowing and rest (without movement). The small intraindividual differences between rowing and rest, in comparison to the typically larger interindividual differences in the ERP waveforms, revealed that ERPs can be measured reliably even in an athletic movement such as rowing. On the other hand, the expected modulation of the motor-related activity by force output was largely affected by movement artefacts. Therefore, for a successful application of ERP measures in movement research, further developments to differentiate between movement-related neuronal activity and movement-related artefacts are required. However, activities with small magnitudes related to motor learning and motor control may be difficult to detect because they are superimposed by the very large motor potential, which increases with force output.
A Data Fusion Orientation Algorithm Based on the Weighted Histogram Statistics for Vector Hydrophone Vertical Array
Authors: Liang Yan , Meng Zhou , Chen Yu , Zhang Yichi , Wang Mingyang , Zhou Xin
Published: October 2020

In this paper, we propose a data fusion algorithm based on the weighted histogram statistics (DF-WHS) to improve the performance of direction-of-arrival (DOA) estimation for the vector hydrophone vertical array (VHVA). The processing frequency band is firstly divided into multiple sub-bands, and the high-resolution multiple signal classification (MUSIC) algorithm is applied to estimate the azimuth of each sub-band for each vector hydrophone. Then, the weighted least square (WLS) data fusion technique is used to fuse the sub-band estimation results of multiple sensors. Finally, the weighted histogram statistics method is employed to obtain the synthesis results in the frequency domain. We carried out a simulation and sea trial of the 16-element VHVA to evaluate the performance of the proposed algorithm. Compared to several traditional processing algorithms, the beam width of the proposed approach is significantly narrower, the side lobes are considerably lower, and the mean square error (MSE) is effectively smaller. In addition, the DF-WHS method is more suitable to accurately estimate the target azimuth with a low signal-to-noise ratio (SNR) because the noise sub-band is suppressed in the weighted histogram statistics step. The DF-WHS method in this article provides a new approach to improve the performance of deep-sea target detection for the VHVA.
Monitoring Shear Behavior of Prestressed Concrete Bridge Girders Using Acoustic Emission and Digital Image Correlation
Authors: Zhang Fengqiao , Zarate Garnica Gabriela I. , Yang Yuguang , Lantsoght Eva , Sliedrecht Henk
Published: October 2020

In the Netherlands, many prestressed concrete bridge girders are found to have insufficient shear–tension capacity. We tested four girders taken from a demolished bridge and instrumented these with traditional displacement sensors and acoustic emission (AE) sensors, and used cameras for digital image correlation (DIC). The results show that AE can detect cracking before the traditional displacement sensors, and DIC can identify the cracks with detailed crack kinematics. Both AE and DIC methods provide additional information for the structural analysis, as compared to the conventional measurements: more accurate cracking load, the contribution of aggregate interlock, and the angle of the compression field. These results suggest that both AE and DIC are suitable options that warrant further research on their use in lab tests and field testing of prestressed bridges.
Co-Occurrence and Levels of Mycotoxins in Fish Feeds in Kenya
Authors: Mwihia Evalyn Wanjiru , Lyche Jan Ludvig , Mbuthia Paul Gichohi , Ivanova Lada , Uhlig Silvio , Gathumbi James K. , Maina Joyce G. , Eshitera Eric Emali , Eriksen Gunnar Sundstøl
Published: October 2020

This study determined the presence, levels and co-occurrence of mycotoxins in fish feeds in Kenya. Seventy-eight fish feeds and ingredients were sampled from fish farms and fish feed manufacturing plants and analysed for 40 mycotoxins using high-performance liquid chromatography-high resolution mass spectrometry. Twenty-nine (73%) mycotoxins were identified with 76 (97%) samples testing positive for mycotoxins presence. Mycotoxins with the highest prevalences were enniatin B (91%), deoxynivalenol (76%) and fumonisin B1 (54%) while those with the highest maximum levels were sterigmatocystin (<30.5–3517.1 µg/kg); moniliformin (<218.9–2583.4 µg/kg) and ergotamine (<29.3–1895.6 µg/kg). Mycotoxin co-occurrence was observed in 68 (87%) samples. Correlations were observed between the fumonisins; enniatins B and zearalenone and its metabolites. Fish dietary exposure estimates ranged between <0.16 and 43.38 µg/kg body weight per day. This study shows evidence of mycotoxin presence and co-occurrence in fish feeds and feed ingredients in Kenya. Fish exposure to these levels of mycotoxins over a long period of time may lead to adverse health effects due to their possible additive, synergistic or antagonist toxic effects. Measures to reduce fish feed mycotoxin contamination should be taken to avoid mycotoxicosis in fish and subsequently in humans and animals through residues.
Chivor’s Life Extension Project (CLEP): From Sediment Management to Development of a New Intake System
Authors: del Río David A. , Moffett Hugo , Nieto-Londoño César , Vásquez Rafael E. , Escudero-Atehortúa Ana
Published: October 2020

Sedimentation is an important issue that has been studied for the watershed of reservoirs, since it increases operational costs of hydropower installations, reduces the life expectancy, and compromises the generation capacity due to volume reduction. This work addresses the implementation of Chivor’s Life Extension Project (CLEP), developed in order to extend the life of La Esmeralda reservoir, which is used for power generation in Colombia. Sediment dynamics studies are first described and connected to the need of the AES Corporation to extend the life expectancy of the Chivor Hydropower Project. The geotechnical and hydraulic designs are described and the main considerations and tools for the execution of such a project are addressed. The construction of the new intake system was developed under favorable geomorphological, geological, and hydrogeological conditions, and the project is being developed without affecting the current operation. Such an innovative project is the first of its class in Colombia and goes from studies of sediment transport and sediment management strategies in the watershed to the design and construction of new intakes, in order to extend the life of an existing 1000-MW (6% of Colombia’s demand) powerplant for 50 more years, contributing to a sustainable energy supply for the future.
Investigating an Innovative Sea-Based Strategy to Mitigate Coastal City Flood Disasters and Its Feasibility Study for Brisbane, Australia
Authors: Khalil Usman , Yang Shu-Qing , Sivakumar Muttucumaru , Enever Keith , Sajid Mariam , Bin Riaz Muhammad
Published: October 2020

This study examines an innovative Coastal Reservoir (CR) technique as a feasible solution for flood adaptation and mitigation in the Brisbane River Estuary (BRE), Australia, which is vulnerable to coastal flooding. The study analysed the operation of a CR by using the MIKE 21 hydrodynamic modelling package. The 2D hydrodynamic model was calibrated and validated for the 2013 and 2011 flood events respectively, with a Nash-Sutcliffe coefficient (Ens) between 0.87 to 0.97 at all gauges. River right branch widening and dredging produced a 0.16 m reduction in water level at the Brisbane city gauge. The results show that by suitable gate operation of CR, the 2011 flood normal observed level of 4.46 m, with reference to the Australian Height Datum (AHD) at Brisbane city, could have been reduced to 3.88 m AHD, while under the improved management operation of the Wivenhoe Dam, the flood level could be lowered to 4 m AHD at Brisbane city, which could have been reduced with CR to 2.87 m AHD with an overall water level reduction below the maximum flood level. The results demonstrated that the innovative use of a CR could considerably decrease the overall flood peak and lessen flood severity in the coastal city of Brisbane.
Simulation Parameter Selection and Steady Seepage Analysis of Binary Structure Slope
Authors: Gao Xuhe , Cheng Baocheng , Tian Weiping , Zhang Zhipei , Li Jiachun , Qi Hongliang
Published: October 2020

The selection of calculation parameters for slope excavation support design and the analysis of seepage stability is a significant challenge. This difficulty also hinders the development of slope support engineering. This study examined the right binary structure slope engineering of the K5 + 220–K5 + 770 section of the TJ1A mark of the Jiangkou-Weng’an Highway in Guizhou province. In this study, we propose and use the deep displacement monitoring data and p value test method to check the simulation parameters. Furthermore, the superposition calculation method for steady-state seepage analysis of slope geotechnical structure is proposed. A comparative analysis of the displacement, strain, stress, and safety factor of the slope after the application of pore water pressure was carried out for three slope conditions. The analysis showed that steady-state seepage has a significant effect on the displacement of the slope during the completion of excavation. As a result, a continuous distribution of strain arises on the slope along the interface between the potential sliding surface and the rock–soil layer, and then forms a continuous sliding zone. Additionally, steady-state seepage has a significant effect on the position of the displacement distribution during the initial support of the slope, leading to a significant increase in the extreme value of the shear outlet displacement of the potential slip surface of the slope and in the extreme value of equivalent strain. Finally, steady-state seepage reduces the displacement and equivalent strain upon construction of the secondary slope support. The steady-state seepage has a limited effect on the stress concentration, but reduces the safety factor calculated using the strength reduction method, in all three stages of slope excavation and support. This study enriches the analysis methods for determining the stability of a dual-structure slope during the rainy season, and provides new ideas for the safety and control of slope support projects.