bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the effect of epicardial adipose tissue thickness on cardiac conduction system in children with type 1 diabetes mellitus
Authors: Güney Ahmet Yasin , Şap Fatih , Eklioğlu Beray Selver , Oflaz Mehmet Burhan , Atabek Mehmet Emre , Baysal Tamer
Published: May 2020

Objectives

Investigation of the association between epicardial adipose tissue thickness (EATT) and P-wave dispersion (Pd), QT dispersion (QTd), corrected QT dispersion (QTcd) and Tp-e interval in children with Type 1 Diabetes Mellitus (T1DM) was aimed.

Methods

Forty-one children with T1DM and 41 age- and gender-matched healthy children were included in the study. Demographical characteristics of all cases were examined. In echocardiography; in addition to conventional echocardiographic measurements, end-systolic EATT was measured from right ventricular free wall. In electrocardiogram; Pd, QTd, QTcd and Tp-e interval durations, as well as Tp-e/QT and Tp-e/QTc ratios were calculated. Correlation values between EATT and electrocardiographic parameters were also noted.

Results

Mean age of the patient group was determined to be 12.43 ± 3.04 years and that of the control group was determined to be 12.08 ± 2.56 years. There was no significant difference between the groups in regard to age, gender, body weight, height and body mass index. In the patient group; EATT, Pd, QTd, QTcd and Tp-e interval were determined to be significantly higher compared to the control group. In the patient group, no significant correlation was determined between EATT and Pd, QTd, QTcd and Tp-e. However, when both patient and control groups were evaluated together, a statistically significant positive correlation was determined between EATT and Pd, QTd, QTcd and Tp-e.

Conclusions

In children with T1DM, an increase in epicardial adipose tissue thickness and in risk of cardiac arrhythmias has been demonstrated. To reveal the possible unfavorable effects of EATT on cardiac conduction system in T1DM patients needs further studies.
The correlation of fetal cardiac function with gestational diabetes mellitus (GDM) and oxidative stress levels
Authors: Jatavan Phudit , Lerthiranwong Thitikarn , Sekararithi Rattanaporn , Jaiwongkam Thidarat , Kumfu Sirinart , Chattipakorn Nipon , Tongsong Theera
Published: May 2020

Background

The primary objective of this study was to compare the fetal cardiac performance index (Tei index) between the fetuses of gestational diabetes mellitus (GDM) mothers and non-GDM mothers; and the secondary objective was to compare various other parameters of fetal cardiac function as well as maternal oxidative stress levels between the groups of GDM and non-GDM mothers.

Methods

A cross-sectional study was conducted on pregnant women at 24–28 weeks of gestation. All of the participants underwent 100 g, 3-h oral glucose tolerance test (OGTT) as a diagnostic test for GDM and were categorized as non-GDM and GDM group. All participants had fetal echocardiography performed for cardiac function, and then maternal blood samples were collected for biomarker measurements.

Results

A total of 80 pregnant women, including 43 in the GDM group and 37 in the non-GDM group, were included in the study. The maternal serum 8-isoprostane (8IsoP), tumor necrosis factor-α (TNF-α) and interleukin (IL)-10 levels were significantly higher in the GDM group than those in the non-GDM group (P: 0.028, P: 0.019 and P: 0.031, respectively). The fetal cardiac function parameters were not significantly different between the two groups. Regardless of the GDM status, the fetuses with high levels of oxidative stress (8Isop ≥1000 pg/mg protein) had a significantly higher rate of impaired shortening fraction (SF) of the left ventricle (P: 0.001).

Conclusion

GDM is significantly associated with an increase in the oxidative stress process, and a high level of oxidative stress was significantly associated with left ventricular (LV) function impairment. Though a correlation between GDM and fetal cardiac function impairment was not clearly demonstrated in this study, this study suggests that GDM patients with a high level of oxidative stress should be evaluated for fetal cardiac function.
Monitoring the incidence, duration and distribution of hyperglycaemia in very-low-birth-weight newborns and identifying associated factors
Authors: Fernández-Martínez María del mar , Gómez-Llorente José Luis , Momblán-Cabo Jerónimo , Martin-González Manuel , Calvo-Bonachera María , Olvera-Porcel María , Bonillo-Perales Antonio
Published: May 2020

Objectives

Hyperglycaemia is a common metabolic disorder in very-low-birth-weight (VLBW) infants and is associated with increased morbidity and mortality. The objective is to describe the incidence, duration, episodes and distribution of hyperglycaemia during the first 7 days of life of VLBW infants.

Methods

This is a prospective cohort study of 60 newborns weighing <1,500 g. Blood glucose levels were monitored with a continuous glucose monitoring system (CGMS) during the first 7 days of life. Hyperglycaemia was defined as glucose ≥180 mg/dL (≥10 mmol/L).

Results

Incidence of hyperglycaemia recorded with the CGMS was 36.6% (95%CI: 24.6–50.1). In almost 74.6±5.48% of these cases the duration of the episode exceeded 30 min and in 45.25% (95%CI: 2.26–57.82) it exceeded 2 h. The condition occurred most frequently during the first 72 h of life. One-fifth of cases were not detected with scheduled capillary tests and 84.6% of these had hyperglycaemic episode durations of 30 min or more. Agreement between the two techniques was very good (r=0.90, p<0.001) and the CGMS proved to be reliable, accurate and safe. Hyperglycaemia detected by a CGMS is associated with lower gestational age (OR: 0.66, p=0.002), lower birth weight (OR: 0.99, p=0.003), the use of ionotropic drugs (OR: 11.07, p=0.005) and death (OR: 10.59, p=0.03), and is more frequent in preterm infants with sepsis (OR: 2.73, p=0.1). No other association was observed.

Conclusions

A CGMS could be useful during the first week of life in VLBW infants due to the high incidence and significant duration of hyperglycaemia and the high proportion of cases that remain undetected. The advantage of the CGMS is that it is able to detect hyperglycaemic episodes that the capillary test does not.
COVID-19 and pregnancy – where are we now? A review
Authors: Rajewska Aleksandra , Mikołajek-Bedner Wioletta , Lebdowicz-Knul Joanna , Sokołowska Małgorzata , Kwiatkowski Sebastian , Torbé Andrzej
Published: May 2020

The new acute respiratory disease severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is highly contagious. It has caused many deaths, despite a relatively low general case fatality rate (CFR). The most common early manifestations of infection are fever, cough, fatigue and myalgia. The diagnosis is based on the exposure history, clinical manifestation, laboratory test results, chest computed tomography (CT) findings and a positive reverse transcription-polymerase chain reaction (RT-PCR) result for coronavirus disease 2019 (COVID-19). The effect of SARS-CoV-2 on pregnancy is not already clear. There is no evidence that pregnant women are more susceptible than the general population. In the third trimester, COVID-19 can cause premature rupture of membranes, premature labour and fetal distress. There are no data on complications of SARS-CoV-2 infection before the third trimester. COVID-19 infection is an indication for delivery if necessary to improve maternal oxygenation. Decision on delivery mode should be individualised. Vertical transmission of coronavirus from the pregnant woman to the fetus has not been proven. As the virus is absent in breast milk, the experts encourage breastfeeding for neonatal acquisition of protective antibodies.
Typological shift in lexicalizing motion events: The case of Wenzhou
Authors: Lin Jingxia
Published: May 2020

Typological shift in lexicalizing motion events has hitherto been observed cross-linguistically. While over time, Chinese has shown a shift from a dominantly verb-framed language in Old Chinese to a strongly satellite-framed language in Modern Standard Mandarin, this study presents the Chinese dialect Wenzhou, which has taken a step further than Standard Mandarin and other Chinese dialects in becoming a thoroughly satellite-framed language. On the one hand, Wenzhou strongly disfavors the verb-framed pattern. Wenzhou not only has no prototypical path verbs, but also its path satellites are highly deverbalized. On the other hand, Wenzhou strongly prefers the satellite-framed pattern, to the extent that it very frequently adopts a neutral motion verb to head motion expressions so that path can be expressed via satellites and the satellite-framed pattern can be syntactically maintained. The findings of this study are of interest to intra-linguistic, diachronic and cross-linguistic studies of the variation in encoding motion events.
An index of teaching performance based on students’ feedback
Authors: Marozzi Marco , Chowdhury Shovan
Published: May 2020

Evaluation of teaching performance of faculty members, on the basis of students’ feedback, is routinely performed by almost all tertiary education institutions.
Objective assessment of faculty members requires a comprehensive index of teaching performance.
A composite indicator is proposed to assess teaching performance of faculty members.
It is based on the combination of several items evaluated by students such as punctuality, communication ability and subject coverage.
Robustness of the indicator is assessed applying uncertainty analysis.
An application to a data set from an Indian institution is presented.
It is shown that the proposed index can be used to rank faculty members from the least to the worst performer according to students’ feedback.
Multilevel Monte Carlo methods and lower–upper bounds in initial margin computations
Authors: Bourgey Florian , De Marco Stefano , Gobet Emmanuel , Zhou Alexandre
Published: May 2020

The multilevel Monte Carlo (MLMC) method developed by M. B. Giles [Multilevel Monte Carlo path simulation, Oper. Res. 56 2008, 3, 607–617] has a natural application to the evaluation of nested expectations

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Apart from the pricing of American-type derivatives, such computations arise in a large variety of risk valuations (VaR or CVaR of a portfolio, CVA), and in the assessment of margin costs for centrally cleared portfolios.
In this work, we focus on the computation of initial margin.
We analyze the properties of corresponding MLMC estimators, for which we provide results of asymptotic optimality; at the technical level, we have to deal with limited regularity of the outer function g (which might fail to be everywhere differentiable).
Parallel to this, we investigate upper and lower bounds for nested expectations as above, in the spirit of primal-dual algorithms for stochastic control problems.
Albion an Holsteins Küsten?Der preußische Generalstab und die Furcht vor einer britischen Landung in Norddeutschland und Dänemark, 1905–1914
Authors: Grawe Lukas
Published: May 2020

Seit dem Herbst 1905 befürchtete die deutsche Militärführung britische Landungen in Schleswig-Holstein oder Dänemark. Ein britisches Korps könnte zur Unterstützung Frankreichs an Deutschlands Nordflanke landen, den Nordostseekanal unterbrechen und auf Kiel und Hamburg vorstoßen. Tatsächlich glaubte der Große Generalstab lange daran, die »Nordoption« sei der britischen Militärführung weitaus sympathischer als eine Landung in Frankreich. Der Beitrag geht der Frage nach, welche Auswirkungen diese Ansichten auf das Handeln des preußisch-deutschen Generalstabs sowie auf dessen Einschätzung eines britischen Kriegsbeitrags hatten. Beleuchtet werden dabei militär‑, außen‑, innen‑ und wirtschaftspolitische Aspekte.
Die (un)mögliche Messung des allgemeinen Rechtsgefühls
Authors: Christoph Stephan
Published: May 2020

Dem Rechtsgefühl der Bevölkerung wird für rechtliche Entscheidungen kaum Bedeutung beigemessen. Dennoch wird in kriminalpolitischen Debatten und auch im Gesetz selbst nicht selten auf die Anschauungen der Allgemeinheit (jedenfalls implizit) abgestellt. Die empirische Erforschung des Rechtsempfindens ist problematisch. Es bestehen noch immer unterschiedliche Vorstellungen darüber, was unter dem Begriff zu verstehen ist und welche Forschungsfragen er umfasst. Auch zeichnet sich der Untersuchungsgegenstand bei näherer Betrachtung durch eine hohe Individualität, Komplexität und Wandelbarkeit aus. Der vorliegende Beitrag möchte Denkanstöße zu Inhalt und Funktionsweise des Rechtsgefühls liefern und so einen Impuls für die weitere Erforschung dieser Thematik setzen. Zudem soll mithilfe von Daten aus einer Studierendenbefragung zur sog. Kronzeugenregelung des § 46 b StGB gezeigt werden, dass man sich allgemeinen Bevölkerungseinstellungen – trotz zahlreicher methodischer Schwierigkeiten – zumindest annähern können dürfte. Hier eröffnen sich neue und attraktive Forschungsfelder für die empirische Kriminologie.
Strafhärteskalierung
Authors: Behnsen Mira
Published: May 2020

Im Bereich der Strafzumessungsforschung ist es erforderlich, die unterschiedlichen Sanktionsarten vergleichbar zu machen und auf einer einheitlichen Strafhärteskala abzubilden. Dieser Artikel gibt zunächst einen Überblick über die bisher erstellten Strafhärteskalen, die entweder ad hoc gesetzt, empirisch ermittelt oder logarithmisch skaliert wurden. In Deutschland gibt es bisher lediglich eine empirisch ermittelte Strafhärteskala, die zudem nur für Geldstrafen und Freiheitsstrafen bis zu zwei Jahren Gültigkeit für sich beanspruchen kann. Der Bereich hoher Freiheits- und Jugendstrafen ist empirisch nicht abgedeckt. Der hier vorgelegte empirische Skalierungsansatz soll einen Beitrag dazu leisten, diese Lücke zu schließen. Richterinnen und Richter an Landgerichten wurden zu ihrer Strafhärteeinschätzung befragt, und die gewonnenen Daten wurden mittels Magnitude-Skalierung skaliert. Die Studie ergab für alle vier untersuchten Sanktionsarten (Freiheitsstrafe mit und ohne Bewährung sowie Jugendstrafe mit und ohne Bewährung) Potenzfunktionen, mithilfe derer jeder ausgeurteilten Sanktion ein Härtewert zugewiesen werden kann.
Luck, Nature and Institutions
Authors: Stark Cynthia A.
Published: May 2020

In addition to having an institutionalsiteorscope, a theory of distributive justice might also have an institutional‘reach’orcurrency. It has the first when it applies to only social (and not natural) phenomena. It has the second when it distributes only socially produced (and not naturally occurring) goods. One objection to luck egalitarianism is that it has absurd implications. In response, Tan has defended a luck egalitarian account that has a strictly institutional reach. I argue, first, that Tan’s view contains two fatal ambiguities and, second, that, to be sound, it requires an institutional currency. This second argument implies that virtually all extant luck egalitarian currencies are incompatible with his approach. I argue, third, that the alleged absurd implications often have little to do with the extent of luck egalitarianism’s reach.
On a system of three difference equations of higher order solved in terms of Lucas and Fibonacci numbers
Authors: Khelifa Amira , Halim Yacine , Bouchair Abderrahmane , Berkal Massaoud
Published: May 2020

In this paper we give some theoretical explanations related to the representation for the general solution of the system of the higher-order rational difference equations

xn+1=1+2yn−k3+yn−k,yn+1=1+2zn−k3+zn−k,zn+1=1+2xn−k3+xn−k,$$\begin{array}{} \displaystyle x_{n+1} = \dfrac{1+2y_{n-k}}{3+y_{n-k}},\qquad y_{n+1} = \dfrac{1+2z_{n-k}}{3+z_{n-k}},\qquad z_{n+1} = \dfrac{1+2x_{n-k}}{3+x_{n-k}}, \end{array}$$

wheren,k∈ ℕ0, the initial valuesx−k,x−k+1, …,x0,y−k,y−k+1, …,y0,z−k,z−k+1, …,z1andz0are arbitrary real numbers do not equal −3. This system can be solved in a closed-form and we will see that the solutions are expressed using the famous Fibonacci and Lucas numbers.
Jointly separating maps between vector-valued function spaces
Authors: Pourghobadi Ziba , Tavani Masoumeh Najafi , Sady Fereshteh
Published: May 2020

LetXandYbe compact Hausdorff spaces,Ebe a real or complex Banach space andFbe a real or complex locally convex topological vector space. In this paper we study a pair of linear operatorsS,T:A(X,E) →C(Y,F) from a subspaceA(X,E) ofC(X,E) toC(Y,F), which are jointly separating, in the sense thatTfandSghave disjoint cozeros wheneverfandghave disjoint cozeros. We characterize the general form of such maps between certain classes of vector-valued (as well as scalar-valued) spaces of continuous functions including spaces of vector-valued Lipschitz functions, absolutely continuous functions and continuously differentiable functions. The results can be applied to a pairT:A(X) →C(Y) andS:A(X,E) →C(Y,F) of linear operators, whereA(X) is a regular Banach function algebra onX, such thatf⋅g= 0 impliesTf⋅Sg= 0, for allf∈A(X) andg∈A(X,E). IfTandSare jointly separating bijections between Banach algebras of scalar-valued functions of this class, then they induce a homeomorphism betweenXandYand, furthermore,T−1andS−1are also jointly separating maps.
Numerical simulation of variable thermal conductivity on 3D flow of nanofluid over a stretching sheet
Authors: Tarakaramu Nainaru , Narayana P.V. Satya , Venkateswarlu Bhumarapu
Published: May 2020

The present investigation deals with the steady three-dimensional flow and heat transfer of nanofluids due to stretching sheet in the presence of magnetic field and heat source. Three types of water based nanoparticles namely, copper (Cu), aluminium oxide (Al2O3), and titanium dioxide (TiO2) are considered in this study. The temperature dependent variable thermal conductivity and thermal radiation has been introduced in the energy equation. Using suitable similarity transformations the dimensional non-linear expressions are converted into dimensionless system and are then solved numerically by Runge-Kutta-Fehlberg scheme along with well-known shooting technique. The impact of various flow parameters on axial and transverse velocities, temperature, surface frictional coefficients and rate of heat transfer coefficients are visualized both in qualitative and quantitative manners in the vicinity of stretching sheet. The results reviled that the temperature and velocity of the fluid rise with increasing values of variable thermal conductivity parameter. Also, the temperature and normal velocity of the fluid in case of Cu-water nanoparticles is more than that of Al2O3- water nanofluid. On the other hand, the axial velocity of the fluid in case of Al2O3- water nanofluid is more than that of TiO2nanoparticles. In addition, the current outcomes are matched with the previously published consequences and initiate to be a good contract as a limiting sense.
MHD fractionalized Jeffrey fluid over an accelerated slipping porous plate
Authors: Jamil Muhammad , Haleem Abdul
Published: May 2020

The primary target of this paper is to obtain the analytic solutions for the incompressible unsteady flow of fractionalized MHD Jeffrey fluid over an accelerating porous plate with linear slip effect is assumed between fluid and the plate. The governing equations of Jeffrey fluid are developed by fractional calculus approach. The velocity distribution and its corresponding shear stress both are obtained in terms of generalized M-function by using Laplace transform technique and considering all initial and boundary conditions. We have also discussed that obtained results of fractionalized MHD Jeffrey fluid for different cases for instance, with and without slip effects, with and without MHD and porosity effects. The influence of the different parameters affected on the flow characteristic is deliberated with the help of graphs. Finally, the analysis among different fluid models exhibits by graphical illustrations.
An experimental study on one-step and two-step foaming of natural rubber/silica nanocomposites
Authors: Bayat Hossein , Fasihi Mohammad , Zare Yasser , Rhee Kyong Yop
Published: May 2020

The curing and cellular structure of natural rubber (NR)/silica composite foams were investigated. The presence of an activator in the rubber formulation significantly lowered the decomposition temperature of the azodicarbonamide foaming agent, which allowed foaming before NR curing. Therefore, two foam methods were designed: foaming initially at 90°C and then curing at 140°C, and foaming and curing simultaneously at 140°C. Two-step foaming generated a lower cell density and higher cell size. Incorporation of nano silica into NR increased the foam density, but decreased the cell size. The higher foaming temperature restricted the bubble growth because of a higher curing rate and inhibited cell coalescence.
Transnational cooperation to develop local barley to beer value
chains
Authors: Halland Hilde , Martin Peter , Dalmannsdóttir Sigridur , Sveinsson Sæmundur , Djurhuus Rólvur , Thomsen Mette , Wishart John , Reykdal Ólafur
Published: May 2020

Transnational cooperation is a common strategy for addressing research and
development (R&D) issues resulting from similar challenges that cut across
administrative borders. Value chains for food and drinks are complex, and
transdisciplinary work is recognised as a method for solving complex issues. The
Northern Cereals project ran from 2015 to 2018, and its goal was to increase cereal
production and the value of grain products in four regions in the Northern Periphery
programme area. The project included both R&D, but the main emphasis was on
development, and was carried out by transdisciplinary cooperation between R&D
partners and small and medium-sized enterprises (SMEs). By reviewing the
project’s methods, outcomes and composition, we discuss if a framework of
transnational and transdisciplinary cooperation can help to develop the value chain
from local barley to beer. We found that transnational cooperation was achieved
successfully, that stakeholder involvement was crucial, but that academic disciplines
such as marketing and innovation could have been included. In addition, we recognised
that much work remains to further increase cereal production and the use of local
grain in the Northern Periphery region, but believe that this project has laid a good
foundation for further progress.
Polarization and Local Conflicts in Post Decentralization Indonesia
Authors: Azis Iwan J. , Pratama Alvin
Published: May 2020

Exploring the hypothesis that socio-economic discrimination contributes to conflict occurrence, we show that the experience of a large country that have gone through a big-bang shift from centralized to decentralized system and introduced direct local elections, confirms the link. Using the case of Indonesia, and by controlling for poverty, demand-induced resource scarcity, and institutional variables, it is revealed that income polarization and inequality at the provincial level explain the occurrence of violent conflict (causing at least 1 death), be it for total or for different types. The results are robust to a series of model specifications. For understanding its impact on conflict, polarization is found more important than income inequality as a measure of socio-economic discrimination.
Invocazione al “signore dell’anima che sempre vive”: Melanipp.PMG762
Authors: Ercoles Marco
Published: May 2020

In Melanipp.PMG762 the reading βροτῶν (v. 1) of the MSS can be retained. The god invoked as “lord of the everlasting soul” (v. 2), generally identified with Dionysus-Zagreus, can be rather recognized as the Orphic Zeus.
The Allegory of the Cave, the Ending of theRepublic, and the Stages of Moral Enlightenment
Authors: Hosle Paul
Published: May 2020

This essay aims to shed new light on the stages of moral enlightenment in the Allegory of the Cave, of which there are three. I focus on the two stages within the cave, represented byeikasiaandpistis, and provide a phenomenological description of these two mental states. The second part of the essay argues that there is a structural parallelism between the Allegory of the Cave and the ending of theRepublic. The parallelism can be convincingly demonstrated by a purely formal analysis, but additionally it complements and reinforces the original interpretation of the Cave, insofar as the ending of theRepublicalso mirrors, on the level of content, the previously adduced stages of moral enlightenment.
Dependence of the crossover zone on the regularization method in the two-flavor Nambu–Jona-Lasinio model
Authors: Morones-Ibarra José Rubén , Mata-Carrizal Nallaly Berenice , Valbuena-Ordóñez Enrique , Garza-Aguirre Adrián Jacob
Published: May 2020

In this article, we study the two-flavor Nambu and Jona-Lasinio (NJL) phase diagrams on theT–μplane through three regularization methods. In one of these, we introduce an infrared three-momentum cutoff in addition to the usual ultraviolet regularization to the quark loop integrals and compare the obtained phase diagrams with those obtained from the NJL model with proper time regularization and Pauli–Villars regularization. We have found that the crossover appears as a band with a well-defined width in theT–μplane. To determine the extension of the crossover zone, we propose a novel criterion, comparing it to another criterion that is commonly reported in the literature; we then obtain the phase diagrams for each criterion. We study the behavior of the phase diagrams under all these schemes, focusing on the influence of the regularization procedure on the crossover zone and the presence or absence of critical end points.
Novel numerical analysis for nonlinear advection–reaction–diffusion systems
Authors: Shahid Naveed , Ahmed Nauman , Baleanu Dumitru , Alshomrani Ali Saleh , Iqbal Muhammad Sajid , Rehman Muhammad Aziz-ur , Shaikh Tahira Sumbal , Rafiq Muhammad
Published: May 2020

In this article, a numerical model for a Brusselator advection–reaction–diffusion (BARD) system by using an elegant numerical scheme is developed. The consistency and stability of the proposed scheme is demonstrated. Positivity preserving property of the proposed scheme is also verified. The designed scheme is compared with the two well-known existing classical schemes to validate the certain physical properties of the continuous system. A test problem is also furnished for simulations to support our claim. Prior to computations, the existence and uniqueness of solutions for more generic problems is investigated. In the underlying system, the nonlinearities depend not only on the desired solution but also on the advection term that reflects the pivotal importance of the study.
Graphene oxide modified carbon fiber reinforced epoxy composites
Authors: Altin Yasin , Yilmaz Hazal , Unsal Omer Faruk , Bedeloglu Ayse Celik
Published: May 2020

The interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.
An enumeration of natural products from microbial, marine and terrestrial sources
Authors: Ntie-Kang Fidele , Svozil Daniel
Published: May 2020

The discovery of a new drug is a multidisciplinary and very costly task. One of the major steps is the identification of a lead compound, i.e. a compound with a certain degree of potency and that can be chemically modified to improve its activity, metabolic properties, and pharmacokinetics profiles. Terrestrial sources (plants and fungi), microbes and marine organisms are abundant resources for the discovery of new structurally diverse and biologically active compounds. In this chapter, an attempt has been made to quantify the numbers of known published chemical structures (available in chemical databases) from natural sources. Emphasis has been laid on the number of unique compounds, the most abundant compound classes and the distribution of compounds in terrestrial and marine habitats. It was observed, from the recent investigations, that ~500,000 known natural products (NPs) exist in the literature. About 70 % of all NPs come from plants, terpenoids being the most represented compound class (except in bacteria, where amino acids, peptides, and polyketides are the most abundant compound classes). About 2,000 NPs have been co-crystallized in PDB structures.
Green analytical solutions for sample preparation: solid phase microextraction and related techniques
Authors: Gionfriddo Emanuela
Published: May 2020

For at least three decades, the analytical chemistry community is striving to apply the principles of Green Chemistry to the development of analytical methods. Many efforts have been made to outline the concept of Green Analytical Chemistry, which helped to redefine analytical procedures and drastically changed the philosophy of analytical method development. This book chapter describes the 12 principles of Green Analytical Chemistry and various methodologies for the assessment of the greenness of analytical methods. The three main steps in the analytical method development – sample preparation, separation and detection- are described in a “green perspective”. Special emphasis is given to the description of green sample preparation procedures, in particular to Solid Phase Microextraction, that, since its introduction in 1989 by Janusz Pawliszyn, has drastically revolutionized the methodology of sample preparation, providing a convenient and green alternative to already existing methods.
Interferon Gamma-induced Formation of Neopterin and Degradation of Tryptophan in Cerebrospinal Fluid of Children with Meningitis but Not with Febrile Convulsions
Authors: Zaknun D. , Zaknun J. , Unsinn K. , Wächter H. , Fuchs D.
Published: May 2020

Endogenously formed cytokines may play an important role in the development of meningitis, and it is necessary to understand in more detail inflammatory cascades involved in the disease process. We were interested to investigate biochemical changes which are inducible by interferon gamma. Therefore, we exa­mined concentrations of neopterin, tryptophan, kynurenine and interferon gamma in cerebrospinal fluid (CSF) of 11 children with bacterial or viral meningitis and of 20 children with febrile convulsions, who suffered from viral or bacterial disease not involving the central nervous system. Concentrations of neopterin (mean ± S.D.: 43.9 ± 34.6 nmol/l) kyunrenine (0.41 ± 0.56 μmol/l) and interferon gamma (0.64 ± 0.81 U/ml) levels were higher in CSF of children with meningitis than in those with febrile convulsions (all p<0.01). In addition, positive correlations resulted between increase of neopterin and changes of tryptophan metabolism in the CSF. Interestingly no difference was found between viral and bacterial meningitis. Our findings indicate that intrathecal immune activation takes place as part of the pathogenesis of meningitis.
Catalytic oxidation of CO over CuO/CeO2nanocomposites synthesized via solution combustion method: effect of fuels
Authors: Cam Thanh Son , Vishnievskaia Tatyana Alekseevna , Popkov Vadim Igorevich
Published: May 2020

A series of CuO/CeO2catalysts were successfully synthesized via solution combustion method (SCS) using different fuels and tested for CO oxidation. The catalysts were characterized by energy-dispersive X-ray analysis (EDXA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), N2adsorption-desorption isotherms and H2temperature-programmed reduction (H2-TPR). It was found that the used fuels strongly affected the characterization and the low-temperature reduction behavior of CuO/CeO2catalysts. The CuO/CeO2-urea catalyst exhibited higher catalytic activity toward CO oxidation (t50=120∘C,t100=159∘C) than the 5 other synthesized catalysts. In addition, the CuO/CeO2-urea catalyst displayed high stability for CO oxidation during five cycles and water resistance. The enhanced catalytic CO oxidation of the synthesized samples can be attributed by a combination of factors, such as smaller crystallite size, higher specific surface area, larger amount of amorphous copper(II) oxide, more mesoporous and uniform spherical-like structure. These findings are worth considering in order to continue the study of the CuO/CeO2catalyst with low-temperature CO oxidation.
Enzymatic degradation study of PLA-based composite scaffolds
Authors: Donate Ricardo , Monzón Mario , Alemán-Domínguez María Elena , Ortega Zaida
Published: May 2020

Disadvantages in the use of polylactic acid (PLA) as a base material for Tissue Engineering applications include the low osteoconductivity of this biomaterial, its acidic degradation and the deficient cellular adhesion on its surface. In order to counteract these drawbacks, calcium carbonate (CaCO3) and β-tricalcium phosphate (Ca3(PO4)2, β-TCP) were proposed in this work as additives of PLA-based support structures. Composite scaffolds (PLA:CaCO3: β-TCP 95:2.5:2.5) manufactured by fused deposition modeling (FDM) were tested under enzymatic degradation using proteinase K enzymes to assess the modification of their properties in comparison with neat PLA scaffolds. The samples were characterized before and after the degradation test by optical microscopy, scanning electron microscopy, compression testing and thermogravimetric and calorimetric analysis. According to the results, the combination of the PLA matrix with the proposed additives increases the degradation rate of the 3D printed scaffolds, which is an advantage for the application of the composite scaffold in the field of Tissue Engineering. The higher degradation rate of the composite scaffolds could be explained by the release of the additive particles and the statistically higher microporosity of these samples compared to the neat PLA ones.
A review on the alterations in the brain of persistent postural-perceptual dizziness patients and non-pharmacological interventions for its management
Authors: Sun Li , Xiang Ke
Published: May 2020

Persistent postural perceptual dizziness (PPPD) is a relatively newer term, and this term is included in the International Classification of Diseases in its 11th revision. The typical features of PPPD include the presence of persistent dizziness, non-spinning vertigo, and unsteadiness, and these symptoms are exacerbated during upright posture, movement, or visual stimuli. Moreover, the structural changes have also been identified in the brains of PPPD patients, particularly in visual, vestibular, and limbic areas. These include a decrease in the volume and gyration of gray matter, a decrease in the blood flow to the cortex region, and alterations in the structural and functional connectivity, particularly in the visual-vestibular networks. Moreover, the impairment in sensory processing is restricted not only to the vestibular and visual regions; instead, there is a generalized impairment in the sensory processing, and thus, there is a multisensory dimension of sensory impairment. Selective serotonin uptake inhibitors and serotonin-norepinephrine reuptake inhibitors are the mainstay drugs for the management of PPPD patients. However, a significant proportion of PPPD patients do not show improvement in response to standard drug therapy. The employment of alternative and complementary treatment strategies, including vestibular rehabilitation therapy, cognitive behavioral therapy, and non-invasive vagal nerve stimulation, is effective in the management of PPPD patients. The present review discusses the alterations in the brains of PPPD patients along with the possible non-pharmacological treatment options in these types of patients.
Mathematical modelling of acute phase of myocardial infarction
Authors: Tsgoev Chermen A. , Voropaeva Olga F. , Shokin Yuri I.
Published: May 2020

A mathematical model of the dynamics of cardiomyocyte death in myocardial infarction during the acute phase of the disease is developed. An economical computing technology of structural and parametric identification of model equations is presented based on the use of experimental data as dynamic parameters and on the idea of splitting the inverse coefficient problem with a large number of unknown parameters into a sequence of simpler inverse problems. The relevance of the proposed mathematical model is confirmed by comparison of the numerical solution to the problem with experimental data and also with the results of modelling of known therapeutic strategies.
Structure of intercalated organic montmorillonite and its pyrolysis properties analyzed using the Agrawal integral equation
Authors: Cui Hui-Wang , Fang Qun , Du Guan-Ben
Published: May 2020

We prepared intercalated organic montmorillonite (OMMT) from a pristine MMT and long-alkyl-chain quaternary ammonium salts (LACQAS). X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analyses revealed that the amount, carbon atoms, and alkyl chains of LACQAS influenced the large value ofd(001)of OMMT significantly. Thed(001)stabilized at 100–150 mmol·(100 g)-1of LACQAS/MMT. The single LACQAS cations arranged in the form of a lateral layer or half-paraffin-type molecular structure between MMT layers, whereas the dual and triple LACQAS cations arranged in the form of a paraffin-type molecular structure. The pyrolysis temperature and maximum pyrolysis rate of OMMT increased greatly compared with those of MMT. The thermal weight loss of MMT was caused by the removed absorbed and structural water, whereas that of OMMT was by the pyrolysis of LACQAS. With the help of the Agrawal integral equation, the pyrolysis kinetics of MMT and OMMT were obtained using a trial-and-error method.
Effect of moisture content of jute fabric and hybridization structure on the impact properties of jute and jute/glass hybrid composites
Authors: Yu Ying , Yang Yuqiu , Tanabe Kazuo , Mastuda Mitsuo , Hamada Hiroyuki
Published: May 2020

A preliminary investigation on the impact properties and morphologies of unsaturated polyester reinforced with jute woven fabric recycled from used coffee bags with different moisture contents was conducted. The laminated structural effect of hybridization with glass woven fabric was also investigated. Jute/jute-laminated composites, and jute/glass/jute- and jute/jute/glass-laminated hybrid composites were fabricated by the hand lay-up method. Their impact properties were compared by drop-weight and the Izod impact tests. The acoustic emission (AE) technique was applied under a tensile load to detect micro-failure processes in the jute and jute/glass hybrid composites. The number of AE signals and the AE energy were monitored using two transducers with resonant frequencies of 140 kHz and 1 MHz. The results showed that the moisture content affected the mechanical properties of the composites. The strength and elongation at break of the jute yarn decreased with a decrease in moisture content. The AE characteristics and observations of the fracture surfaces revealed that the composites fabricated from jute fabric with low moisture content had a relatively higher initial fracture stress and higher resistance to micro-fractures. Moreover, the mechanical properties of the hybrid composites were significantly affected by the laminating structure.
Microstructure-based modeling of the dynamic mechanical properties of SiCp/Al composites
Authors: Yuan Mei Ni , Yang Yan Qing , Gong Qiao Juan , Li Chao , Lang Xian Zhong
Published: May 2020

Using image processing and recognition, a microstructure-based finite element model (FEM) was established to predict the dynamic properties of SiCp/Al composites at different strain rates ranging from 200 to 14,000 s-1. In the microstructure-based FEM, the irregular SiC particles were randomly distributed in the matrix, and its configurations did not change. The results showed that the flow stress of SiCp/Al composites with low particle volume fraction first increases and then decreases with the increasing of strain rate during the adiabatic compression. The reducing flow stress of SiCp/Al composites is caused by the inner damage and the heat softening of composites. The angular particles in SiCp/Al composites provide more strengthening effect than the circle particles when the strain is <0.62, while the circle particles provide more strengthening effect than the angular particles for strain >0.62.
Comparing the influence of different kinds of zirconia on properties and microstructure of Al2O3 ceramics
Authors: Li Wenfeng , Li Suping , Zhong Xiangchong
Published: May 2020

This paper compared the influence of fused zirconia-corundum (AZ40), monoclinic zirconia (m-ZrO2), and 3 mol% yttria-stabilized zirconia (3Y-ZrO2) on physical properties at room temperature, hot modulus of rupture, and thermal shock resistance of Al2O3 ceramics, and their relationships with microstructure changes were investigated. It was found that m-ZrO2 or 3Y-ZrO2 addition promoted the process of sintering densification and enhanced the room temperature strength and the hot modulus of rupture of Al2O3 ceramics, and the effect of the latter was more distinct, while those of the sample with AZ40 addition decreased. In addition, the three kinds of ZrO2 were beneficial to improving the thermal shock resistance of Al2O3 ceramics. All these changes had close relationships with the changes of corresponding microstructure characteristics (including distribution of particles, degree of contact between crystals, grain boundary solid solution, microcrack density) and phase composition.
Comparing Test Methods for the Intra-ply Shear Properties of Uncured Prepreg Tapes
Authors: Heller Klaus , Hallmannseder Moritz , Colin David , Kind Kalle , Drechsler Klaus
Published: May 2020

To achieve cost-efficient manufacturing and a high part quality in Thermoset Automated Fiber Placement (TS-AFP), knowledge about the interaction between material and process parameters is of special interest. Material properties of prepregs are well known at the cured state of the resin. However, there are no standardized test procedures for the mechanical behavior of the uncured prepreg tapes. To investigate the intra-ply shear deformation behavior of uncured unidirectional prepreg tapes, we compared several measurement procedures and conducted experiments for rheometer based tests using 8552/AS4 material. We identified a rotational parallel platens rheometer test method and a torsion bar rheometer test method to be suitable. Experiments using both methods revealed that the Torsion Bar Test has a higher repeatability and the analysis is less complex. Furthermore, first results show that changes in material properties caused by aging can be analyzed using this method. In the future,we will use the Torsion Bar Test to characterize changes in deformation behavior due to material aging as well as material modifications. By this, we will be able to provide data for the material modeling thus enabling the prediction of lay-up defects such as buckling due to steering.
Research on Influence mechanism of composite interlaminar shear strength under normal stress
Authors: Li Fei , Deng AnZhong , Zhao QiLin , Duan Jinhui
Published: May 2020

The normal stress along the shear plane has great effect on the composite intralaminar shear strength. However, the influence mechanism on composite interlaminar shear strength under the normal stress along the shear plane was not truly reflected by the double-notch shear experiment. In this paper, the interlaminar shear strength of composite specimens under different external normal stresses was first obtained using the improved double-notch shear experiment. Furthermore, to research the influence mechanism on interlaminar shear strength under normal stress along the shear plane, the characteristic curve method based on the double-notch shear specimen was studied. Finally, the experimental results analyzed by the characteristic curve method were compared with a range of failure criteria presented in the literature. The experimental data obtained in this study agreed best with the NU theory criterion, with a maximum numerical difference of 4%. And the NU theory criterion can reflect the influence mechanism of the composite interlaminar shear strength best.
Psychological resilience associates with pain experience in women treated for breast cancer
Authors: Liesto Sanna , Sipilä Reetta , Aho Tommi , Harno Hanna , Hietanen Marja , Kalso Eija
Published: May 2020

Background and aims

Psychological resilience refers to successful adaptation or a positive outcome in the context of significant life adversity, such as chronic pain. On the other hand, anxiety closely associates with pain. The aim of this study was to explore how anxiety and psychological resilience together associate with persistent and experimental pain.

Methods

In a cross-sectional design, we studied 160 patients who had previously been treated for breast cancer and who now reported at least moderate pain (NRS ≥ 4) in any area of the body. Psychological resilience was measured on the Resilience Scale-14, anxiety on the Hospital Anxiety and Depression Scale, and intensity and interference of persistent pain by means of the Brief Pain Inventory. The cold pressor test was conducted to assess sensitivity to experimental cold pain.

Results

The results showed that resilience associated with pain interference in persistent pain, and that anxiety moderated this effect. Higher psychological resilience was associated with lower pain interference and this association was stronger in patients with low anxiety than among patients with high anxiety. These effects were visible with regard to persistent pain but not in experimental cold pain.

Conclusions

These results indicate that chronic pain and experimental pain as well as pain severity and pain interference are psychologically different phenomena. Psychological resilience protects against pain interference but effectively only in patients with low anxiety. It is necessary also to consider protective factors in addition to vulnerability factors in cases of persistent pain.

Implications

Resilience has been considered a potential target for intervention in chronic pain. However, high levels of anxiety might diminish the protective effect of psychological resilience in clinical settings. Therefore, it is important to treat anxiety in addition to resilience enhancing interventions. Patients with low psychological distress might be more suitable for resilience enhancing interventions than patients with high anxiety.