bluuebunny/crossref_metadata_2025 huggingface dataset:
Internet Technologies in Distance Education
Authors: Ushanov Alexander , Morgunovа Natalia , Petunina Irina
Published: May 2021

In modern education, a new format of distance learning is developing more and more rapidly - massive open online courses (MOOCs), this is especially important in times of quarantines and remote learning. The aim of the research is to study the attitude of teachers and students to MOOCs and their readiness to implement this practice in the educational process. 2145 students and 1050 teachers of higher educational institutions of the Russian Federation voluntarily took part in the study. The analysis of the survey data was made in the STATISTICA system. It has been found that more than 30% of respondents have an idea of MOOCs. It has also been determined that 31% of students and 28% of teachers are positive about the introduction of MOOCs in the educational process of universities. In addition, it has been determined that 31% of students and 23% of teachers plan to take MOOCs. Overall, the survey results showed a fairly good acceptance of MOOCs by respondents. From this, it can be concluded that in the near future, taking into account the reorganization of the educational process, MOOCs may become a worthy alternative to traditional education. It is for this that the results of this study can be used by the administration of the universities that have taken part in the survey, in order to further inform students and teachers about MOOCs. There is also a need to reorganize, revise, implement and provide an opportunity for students to study through such a form of distance learning as MOOCs.
Boosting Motivation to Help Students to Overcome Online Learning Barriers in Covid-19 Pandemic: A Case study
Authors: Nguyen Hong-Thu Thi
Published: May 2021

In response to a public health emergency of COVID-19 pandemic, changing learning and teaching from face to face mode to online one is determined to be imperative. The fact that classrooms were temporarily prevented from continuing did not mean that learning and teaching were suspended. It was going on in a new approach supported by technology, which challenges students and teachers with various barriers. The paper explored the correlation between online learning barriers and motivations, whether the motivation-boosting strategies could help students overcome challenges in online learning duration and had any impact on students’ academic achievement or not. A quasi-experimental research was applied for 288 third-year students of law joining the second criminal law course at a university in Viet Nam. The experiment was conducted with the assistance of LMS, Microsoft Team, Skype and Zoom, along with Socrative, Kahoot and Social networks. The findings revealed that the extrinsic barriers had more impact on motivation than intrinsic ones; extrinsic barriers had high impact on the motivation and the learning results of students compared to the traditional learning method. The data also expressed that the motivation-boosting activities in the online learning process led positive changes in students’ learning motivation and academic achievement.
A Challenge in Organizations
Authors: Ribeiros Dário , Ventura Paula , Fernandes Silvia
Published: May 2021

The chapter intends to exemplify process innovation challenges and trends. A case is studied—stock management—at an important enterprise in Portugal. It involves the analysis and improvement of this process within a firm related with gas distribution. Stock management is critical to deliver value to other processes such as sales. This issue has led to a focus on improving the inventory process. As it involves sub-value chains, this work highlights a comparison between current process and its proposed redesign. DMAIC method (define-measure-analyze-improve-control) is systematically applied, and new data emerge from tests made in the ERP (enterprise resource planning system) of the company. The improved process tends to greatly reduce execution time, as well as the number of actors and amount of information circulating outside the system. Other aspects are studied in line with new trends in ERP platforms due to cloud computing.
Automatic Keyword Extraction From Text Documents
Authors: Goz Furkan , Mutlu Alev
Published: May 2021

Keyword indexing is the problem of assigning keywords to text documents. It is an important task as keywords play crucial roles in several information retrieval tasks. The problem is also challenging as the number of text documents is increasing, and such documents come in different forms (i.e., scientific papers, online news articles, and microblog posts). This chapter provides an overview of keyword indexing and elaborates on keyword extraction techniques. The authors provide the general motivations behind the supervised and the unsupervised keyword extraction and enumerate several pioneering and state-of-the-art techniques. Feature engineering, evaluation metrics, and benchmark datasets used to evaluate the performance of keyword extraction systems are also discussed.
Influence of Microwave on the Structure and Properties of Nanomodified Fluoroplastic
Authors: Zavrazhin D.O. , Chuprikova A.A. , Povetkina Ju.S.
Published: May 2021

Polymers modified with carbon nanomaterials exhibit enhanced electrical conductivity. The modifier, which is qualitatively distributed in the polymer matrix, actively absorbs microwave waves even with an extremely small introduced volume (up to 1.5 mass parts). Photographs obtained by scanning electron microscopy indicate a uniform distribution of carbon nanotubes in the matrix of fluoroplastic 4. The microwave treatment of the obtained composites showed a significant increase in the temperature of the samples with a heating time of up to 100 sec. even with minimal amounts of modifier added. Strength characteristics for a uniaxial plant of modified materials after microwave increase by 40-50%.
The obtained modified materials based on a non-polar polymer matrix have enhanced characteristics of absorption of microwave radiation.
Fundamentally New Composite Materials of Fast Reactors Made on the Basis of Nanotechnology
Authors: Okunev V.S.
Published: May 2021

The main goal of the work is to identify the advantages of fast reactors when using nanotechnology in the manufacture of core materials. The research methods are based on the adaptation of known technologies (including powder metallurgy) to the design of fast reactors and on the numerical simulation of physical processes carried out using computer programs for the analysis of emergency conditions of fast reactors (including anticipated transient without scram - ATWS). The results of the research show that the use of structural materials based on steels hardened by nanooxides in combination with fundamentally new types of fuel based on composite materials can significantly improve the safety of nuclear technics. Sintered mixtures of ceramic microgranules (oxide, nitride) and nanoadditives of metallic beryllium or uranium are considered as nuclear fuel. Such composite nuclear fuel improves reactor safety and power. The following types of composite fuel were analyzed: mixed oxide with additives of a beryllium or uranium nanopowder, mixed mononitride with additives of a beryllium or uranium nanopowder. Most preferably, a ceramic-metal pellet fuel based on mononitride microgranules and uranium metal nanopowder. The use of such fuel (with a volume fraction of metallic uranium up to 20%) significantly increases the safety of the reactor, combining the advantages of metal and ceramics and completely neutralizing their disadvantages. The proposed materials are of practical importance in the development of new concepts of nuclear technics, in the transition to large-scale nuclear power and high-power reactors. The use of a new cermet-based composite fuel increases the power of the reactor and significantly increases the safety of the reactor.
Surface Carboxylation of a Boron-Carbon BC5 Nanotube in the Development of Sensor Devices
Authors: Zaporotskova I.V. , Dryuchkov E.S. , Vilkeeva D.E.
Published: May 2021

This article discusses the possibility of the fabrication of a highly sensitive sensor based on single-walled boron-carbon BC5 nanotubes surface modified with functional carboxyl groups (-COOH). The sensor potential for detection of alkali (lithium, potassium, and sodium) metals were investigated. The results of computer simulation of the interaction process between the sensor and an arbitrary surface of the modified tube containing atoms of the studied metals are presented. The carboxylated BC5 nanotube and a similarly modified BC3 nanotube was compared. The effect of boron atoms on sensory properties of the obtained system is concluded. The calculations were carried out within the framework of the density functional theory (DFT) method using the molecular cluster model. It has been proved that surface-modified boron-carbon nanotubes by carboxyl group show high sensitivity for the metal atoms under study and can be used as the sensor device.
Influence of Structure and Dispersivity of Copper on its Melting Features
Authors: Korshunov A.V.
Published: May 2021

The melting parameters (melting point, specific heat of fusion) of copper samples with different volume structure (fine-grained, submicrocrystalline) and dispersivity (fine powder) were explored using differential thermal analysis. It was found that change in the metal structure from bulk coarse-grained to submicrocrystalline, and to submicron powders led to depression of melting point by ~18 °C and of specific heat of fusion by ~45 % relative to the standard values. It was shown that the high-energy impact on the starting coarse-grained metal used to obtain the samples with modified structure and dispersivity (severe plastic deformation, electric explosion of thin wires) caused changes in the composition of the material. An explanation for the observed influence of structure and dispersion factors on the melting parameters has been proposed on the basis of X-ray diffraction data, electron microscopy, and model calculations.
Grinding of Titanium Alloys
Authors: Nosenko Vladimir A. , Nosenko S.V. , Puzirkova V.E.
Published: May 2021

X-ray spectroscopic microanalysis was used to determine the concentration of titanium on the surface of the wear spot of a silicon carbide crystal during micro-scratching and the concentration of silicon on the treated surface after grinding by a wheel of silicon carbide. The wear resistance and grinding coefficient of titanium alloys under micro-scratching with single crystals and grinding with wheels made of corundum, silicon carbide, cubic boron nitride and diamond were determined. The morphology of the treated surface and the regularities of changes in the indicators of the grinding process of titanium alloys with circles of various characteristics were studied. The features of the process of grinding titanium alloys using various lubricants and coolants are shown. The influence of the characteristics of the abrasive tool and grinding modes on low-cycle fatigue on the operation of flat and round grinding of samples made of titanium alloys VT9 and VT22 was studied. The influence of abrasive material, grinding speed, feed and sparkout during finishing on low-cycle fatigue was analyzed. Based on the research, recommendations were given for choosing a rational characteristic of the abrasive tool and processing modes.
Kinetic Characteristics of Electrodeposition of Ni-Co-Al2O3 Composite Coating
Authors: Zhukova I.Y. , Degtyar L.A. , Bobrikova I.G.
Published: May 2021

The kinetic features of electrodeposition process of a wear-and corrosion-resistant composite electrochemical nickel-cobalt-aluminum oxide coating were investigated. Potentiodynamic studies showed that in the process of the CEC formation at the cathode the electrode polarization decreases, and the value of the limiting current density increases by more than twice. Consequently, the rate of the CEC electrodeposition process increases and the range of operating current densities expand in comparison with the control coating with the Ni-Co alloy. Temperature-kinetic, chronopotentiometric methods, values of the temperature coefficient of the reaction rate and the diffusion coefficients of nickel ions were used to determine the mechanism of CEC electrodeposition. As the result of determining the nature of limiting stage of the electrodeposition process of CEC nickel-cobalt-aluminum oxide, it was found that it is caused by such two coupled processes proceeding at comparable rates, as electrophoretic transfer of electroactive particles to the cathode and overgrowing of dispersed particles adsorbed on the cathode surface with electrodeposited metals.
Improving the Tribological Properties of Ceramic Dies
Authors: Alisin Valery V.
Published: May 2021

The article is devoted to tribological studies of a ceramic composite with a zirconia-based die in order to replace carbide wire drawing dies with ceramic. Sliding friction was done according to the scheme finger-disk without lubrication and with lubrication. The wear rate and friction coefficients were determined, on the basis of which it is proposed to produce portage dies-blanks from zirconium ceramics. The influence of sintering temperature on the mechanical properties of ceramics, especially cracking resistance, was studied. The optimum sintering temperature was determined by the criterion of fracture toughness. The formation of defects after the final firing was investigated. It was found that sintering at a temperature of 1600 ° C is more promising. An trial batch of zirconium ceramic dies showed positive results in the process of drawing copper wire in industrial situations.
Impact of Nanodispersed Diamond Graphite Additive on Metal Cutting Temperature
Authors: Petrovsky E.A. , Bashmur K.A. , Tynchenko Vadim S.
Published: May 2021

The present study describes the impact of cutting speed and various lubricant-cooling process agents on the temperature of alloy turning. The research was conducted for NiCr20TiAl and N07750 nickel alloys with the help of HG30 and HS123 carbide-tipped cutting tools. New lubricant-cooling process agents with nanodispersed diamond graphite additives are studied. The optimal composition of the diamond graphite additives is revealed when cutting these alloys. It is demonstrated on the basis of tests the positive effect of diamond graphite agents on the quantitative changes in measured cutting temperatures. In doing so, the cutting speed and the lubricant-cooling agents applied to the cutting zone have little impact on the nature of temperature patterns.
Analysis of the Quality of Quartz-Feldspar Sand as a Component of a Composite Binder
Authors: Popov A.L. , Strokova V.V. , Mestnikov A.E.
Published: May 2021

The modern construction industry is more and more inclined to use composite binders instead of traditional binders. Composite binder is characterized by increased efficiency and environmental friendliness, improved performance characteristics at a reduced cost and energy consumption. Based on this, studies are needed to determine the possibility of using quartz-feldspar sand as a component of composite binders.
Influence of Fillers on Silicate Compositions Porization
Authors: Miryuk O.A.
Published: May 2021

The article is devoted to the problem of raw material base expanding and improving construction and technical properties of porous granular materials. The results of experimental studies of silicate compositions based on liquid glass and technogenic fillers containing burnable or gas-forming components are presented. Influence of molding mixtures’ composition on thermal expansion nature of granular compositions was established. Preference of a filler combined, containing glass cullet, silica clay and mineral additives was revealed. Multicomponent composition of a filler helps to intensify composition’s expansion. Electron microscopy studies of porous silicate granules have confirmed the advantages of combined fillers using. Effectiveness of sodium additive introduction to regulate technological properties of the raw material and the process of pores formation has been proven. Expediency of mechanical activation of a raw mixture to reduce the temperature of expansion and obtain granules with a bulk density of not more than 300 kg/m3 has been determined.
Research of Physical and Mechanical Properties of Fly Ash Ceramics with SiO2 and Al2O3 Nanoparticles as Functional Addition
Authors: Kalneus V.A. , Nemushchenko D.A. , Larichkin V.V. , Briutov A.A.
Published: May 2021

The article analyses the influence of SiO2and Al2O3nanopowders on properties of ceramics consisting of fly ash from thermal power plants, glass waste, and clay binder. Based on studies of physical and mechanical properties of the obtained ceramics (ultimate compressive strength, ultimate three-point bending strength, wear resistance, and water absorption), the paper shows the positive influence of the nanoadditives. The optimal number of SiO2and Al2O3nanopowders in the formulation is 0.5 wt. % that has the strongest effect on ultimate compressive strength and water absorption of the fly ash ceramics samples. The direction of further research on improving the properties of ceramic products is an application of the Al2O3nanopowder as more perspective nanoadditive using clay dispersant.
Methodology for Calculating Heat Loss in the Study of Friction Stir Welding
Authors: Statsenko V. , Sukhorada A. , Mikhailova N.
Published: May 2021

Currently, the most promising high-tech and productive process is friction stir welding. An important element of this technology is the determination of the material temperature in the stir zone, which can be determined by calculation based on the amount of heat input introduced into the welding zone. To determine this value, experimental of the dependence of heat input on the tool rotation speed and welding speed were carried out. For this, a scheme of experiments has been selected in which the material to be welded (aluminum alloy AMg5) is modeled as an experimental tube with a diameter of 20 mm, and the tool (made of tool steel R6M5) is modeled as a working plate. On the designed and manufactured stand, studies of the dependence of the heat-liberation value for the speeds of rotation of the experimental tube 42-105 rad/s were carried out. In this case, due to the pressing force of the experimental tube and the working plate, a constant temperature of the place of friction was maintained. The obtained experimental data were used to calculate the heat-liberation value and heat power on each concentric ring 2 mm wide at the end of the working tool with a diameter of 20 mm, as well as the total heat power for different speeds of rotation and welding.When carrying out experiments on the bench, heat losses were determined by thermal conductivity along the rod on which the experimental tube is fixed, as well as from the working plate made of tool steel through the gasket onto the working table and by convection from the surface of the rotating experimental tube into the environment. The calculation results showed that each of these losses does not exceed 3-10%. These losses are taken into account in the heat supply calculations.
Effect of Initial Conditions and Numerical Investigation of Instability Developed during Synthesis of TiC via Vortex Combustion at Moderate Temperatures. Model of Vortex Combustion
Authors: Markov Andrey A. , Filimonov I.A.
Published: May 2021

Despite the fact that the classical theory of combustion (CTC) operates with the simplest, elementary objects and concepts, such as: flat or slightly curved combustion fronts, elementary combustion models and potential flows. there are some problems that the CTC is only facing with a sufficiently strong curvature of the front. For example, Markstein's solution in the problem of hydrodynamic instability of a plane combustion front. In the work presented by the authors, the problem of stabilizing the titanium carbide synthesis front at moderate temperatures, which cannot be plane due to the thermo physical features of the system under consideration (Le<<1, Ze=6.03 at Тad=3300К), is similarly solved. A model of vortex combustion with a spirally curved front is proposed, the numerical analysis of which showed the stability of similar front of the TiC synthesis in the field of vortex hydrodynamic currents. The resulting solution can serve as a complete alternative to the mode of spiral spin combustion (or rather, to its branch with a low orbital speed and a low combustion temperature) of such systems, not only considered conditionally unstable in CTC, but also actually manifesting this instability during numerical calculations of the area of the existence of a spinal spot with a small radius and great curvature.
Investigation of BaSO4-KPO3-Na2B4O7 Low-Melting Glass System as a Basis for Synthesis of a Glass-Solder Material
Authors: Stolbovsky Alexey , Vyatchina Vita
Published: May 2021

The possibility of using the compositions of BaSO4-KPO3-Na2B4O7 system as a glass-solder (frit) material was shown. A glass formation region has been established in BaSO4-KPO3-Na2B4O7 system which is located in the borate-phosphate part of the concentration triangle and occupies ~41% of the triangle area. The concentration dependences of linear thermal expansion coefficient (TCLE), the softening temperature and the glass transition temperature was determined and discussed. It is established that the glass formation region, the concentration dependences of TCLE and technological temperatures values are significantly closer to those for CaSO4-KPO3-Na2B4O7 system than for MgSO4-KPO3-Na2B4O7 system. That may point out at the similar effect barium sulphate and calcium sulphate doping in the sulphate-phosphate-borate systems.
Calculated Model of Endurance Limit Estimation Based on Structural-Strain Analysis of the Critical Condition of Ferrite-Perlite Steels with Macrocracks in Ship Structures
Authors: Molokov K.A. , Novikov V.V. , Turmov G.P. , Domashevskaya Ya.R.
Published: May 2021

In this study, a structural-deformation analysis of the process of crack development is performed, on the basis of which an engineering methodology is developed for assessing the endurance limit and resource of large-sized structures. A simple analytical dependence (correlation аналитическая зависимость) was obtained, which allows one to determine the critical size of macrocracks for ferritic-pearlitic steels without using the well-known Griffith formula. The results of calculating the cracks critical lengths of various steels depending on their yield strength are presented. The analytical dependence of the calculation of the fatigue limit for the most dangerous symmetric loading cycle according to the standard set of mechanical characteristics of ferrite-pearlite steel is presented. The obtained results make it possible to calculate the endurance limit of structural elements of marine equipment and other structures subject to cyclic loads
Visualization of the Effect of an Impurity on the Optical Homogeneity of Lithium Niobate Doped with Boron Cations
Authors: Pikoul O. , Sidorov Nikolay V. , Palatnikov Mikhail N.
Published: May 2021

The laser conoscopy method confirms the high optical uniformity of LiNbO3:B crystals in the range of B2O3 concentrations from 0.008 to 1.24 mol. %. Minor signs of anomalous optical biaxiality appear in the conoscopic patterns of crystals at boron concentrations of 0.12 and 0.83 mol. % at a laser power of 90 mW. The maximum value of the angle of anomalous optical axes for the studied samples is 2V = 10 ́ for the sample (0.12 mol. %), аnd the value of anomalous birefringence corresponds to ∆n = 0.02·10-5.
Dynamic Parameters of Prestressed Hanging Systems
Authors: Razzokov N.S. , Akhmadiyorov U.S.
Published: May 2021

The dynamic parameters of long-span prestressed one and two-belt hanging roofs, for which the seismic wavelengths are commensurate with the dimensions of the structure in plan, are considered. Calculated expressions have been obtained to determine the dynamic parameters for symmetric and skew-symmetric oscillations depending on the length of seismic waves.To ensure the operational safety of unique buildings and structures, we studied the change in the structural properties of materials from unfavorable operating conditions, long-term, beyond design-basis static loads, high-intensity dynamic effects, compliance of the support contours and the possibility of local damage and from the failure of cables of the structures under study.
On the Influence of Interlayer Nonuniformity on Contact Characteristics during the Interaction of a Pipe and a Rigid Cylindrical Insert
Authors: Kazakov Kirill E.
Published: May 2021

Contact problem for viscoelastic aging pipe with a longitudinally nonuniform thin elastic internal coating and a rigid cylindrical insert is considered in the paper. The basic integral equation with integral operators of different types (mixed integral equation) is given. It's analytical solution for contact stresses in insert area is presented. The solution is constructed in such a way that the function describing the inner coating nonuniformity is distinguished by a separate factor. This fact allows one to perform accurate calculations even in cases where the coating properties are described by rapidly changing and even discontinuous functions. Other known analytical methods do not allow one achieving such a results.
Risk factors for patient selection in ambulatory laparoscopic cholecystectomy
Authors: Wu Qiang , Fu Ning , Chen Weiwei , Jin Xueli , He Lei , Mo Chencheng , Chen Jiao , Luo Daoyun , Ma Minkun , Yang Hongqiang , Hao Jingcheng
Published: May 2021

Backgrounds:

Ambulatory laparoscopic cholecystectomy (LC) reduces healthcare cost and increases hospital bed capacity. Currently, there is no consensus on patient selection for ambulatory LC. Evaluation of risk factors for ambulatory discharge is essential.

Materials and Methods:

Consecutive patients who underwent LC in our centre throughout 2019 were collected. We evaluated the discharge fitness using the Post-Anaesthetic Discharge Scoring System at 8 h after the operation. The relations between pre-operative variables and dischargeable possibilities were analysed for screening risk factors. Furthermore, we performed a literature review to summarise all published information.

Results:

Six hundred and forty-one cases were included in this study. American Society of Anaesthesiologist (ASA) grading (odds ratio OR = 0.415, P = 0.001) and leucocytes (OR = 0.80, P < 0.001) significantly predicted the fitness of discharge. ASA contributed to lower activity (P = 0.002) and intake/output (P = 0.006) scores. Leucocytes influence the vital sign (P < 0.001) and pain or post-operative nausea and vomiting (PONV) (P < 0.001) scores. The prolonged operation could predict the inabilities of discharge with a cut-off value of 55 min by dropping vital signs (P = 0.011), activity (P < 0.001) and pain or PONV (P = 0.012) scores. Male sex (OR: 1.702, P = 0.010), body mass index (BMI) (OR: 1.087, P = 0.008), leucocytes (OR: 1.075, P = 0.017) and C-reactive protein (CRP) (OR: 1.018, P = 0.003) were predictors for prolonged operation (>55 min).

Conclusions:

We suggest that pre-operative ASA grading III and leucocytes are risk factors for the fitness of ambulatory discharge after LC and intraoperative time. Male, BMI and CRP predict complicated surgery, and they should be considered preoperatively.
Gordon's conjectures 1 and 2: Pontryagin-van Kampen duality in the hyperfinite setting
Authors: Zlatos Pavol Jan
Published: May 2021

Using the ideas of E. I. Gordon we present and farther advancean approach, based on nonstandard analysis, to simultaneousapproximations of locally compact abelian groups and their dualsby (hyper)finite abelian groups, as well as to approximations ofvarious types of Fourier transforms on them by the discrete Fouriertransform. Combining some methods of nonstandard analysis andadditive combinatorics we prove the three Gordon's Conjectureswhich were open since 1991 and are crucial both in the formulationsand proofs of the LCA groups and Fourier transform approximationtheorems
Almost disjoint families and ultrapowers
Authors: Anoussis Michalis , Felouzis Vaggelis , Tsaprounis Konstantinos
Published: May 2021

We prove estimates for the cardinality of set-theoretic ultrapowers in terms of the cardinality of almost disjoint families. Such results are then applied to obtain estimates for the density of ultrapowers of Banach spaces. We focus on the change of the behavior of the corresponding ultrapower when certain ‘‘completeness thresholds’’ of the relevant ultrafilter are crossed. Finally, we also provide an alternative characterization of measurable cardinals.
A compactness theorem for the fractional Yamabe problem, Part I: The nonumbilic conformal infinity
Authors: Kim Seunghyeok , Musso Monica , Wei Juncheng
Published: May 2021

Assume that

(X, g^+)

is an asymptotically hyperbolic manifold,

(M, [\bar{h}])

is its conformal infinity,

\rho

is the geodesic boundary defining function associated to

\bar{h}

and

\bar{g} = \rho^2 g^+

. For any

\gamma

in

(0,1)

, we prove that the solution set of the

\gamma

-Yamabe problem on

M

is compact in

C^2(M)

provided that convergence of the scalar curvature

R[g^+]

of

(X, g^+)

to

-n(n+1)

is sufficiently fast as

\rho

tends to 0 and the second fundamental form on

M

never vanishes. Since most of the arguments in the blow-up analysis performed here are insensitive to the geometric assumption imposed on

X

, our proof also provides a general scheme toward other possible compactness theorems for the fractional Yamabe problem.
Fundamental classes in motivic homotopy theory
Authors: Déglise Frédéric , Jin Fangzhou , Khan Adeel A.
Published: May 2021

We develop the theory of fundamental classes in the setting of motivic homotopy theory. Using this we construct, for any motivic spectrum, an associated twisted bivariant theory, extending the formalism of Fulton and MacPherson. We import the tools of Fulton’s intersection theory into this setting: (refined) Gysin maps, specialization maps, and formulas for excess of intersection, self-intersections, and blow-ups. We also develop a theory of Euler classes of vector bundles in this setting. For the Milnor–Witt spectrum recently constructed by Déglise–Fasel, we get a bivariant theory extending the Chow–Witt groups of Barge–Morel, in the same way the higher Chow groups extend the classical Chow groups. As another application we prove a motivic Gauss–Bonnet formula, computing Euler characteristics in the motivic homotopy category.
Estimating the effect of nasal steroid treatment on repeat polypectomies: survival time analysis using the General Practice Research Database
Authors: Punekar Y.S. , Ahmad A. , Saleh H.A.
Published: May 2021

BACKGROUND: Intranasal steroids are effective in preventing or delaying recurrence of nasal polyps. However, their effectiveness in delaying a need for repeat polypectomy in clinical practice is unknown. OBJECTIVES: To compare time to a repeat polypectomy between post-polypectomy intranasal steroid users and non-users. METHODOLOGY/PRINCIPLE: Our cohort consisted of patients in GPRD who had undergone at least one nasal polypectomy procedure in or after the year 2000. These patients were followed for up to 4 years and the time to next polypectomy was estimated. Cox`s proportional hazards regression was used to estimate the effect of post polypectomy intranasal steroid treatment on time to the next polypectomy after controlling for other respiratory conditions and their treatment. RESULTS: The cohort consisted of 1,675 patients with a mean age of 59 years and 68% males. Of these, 576 patients were post-polypectomy steroid users and 1,099 patients were steroid non-users. The median time to repeat polypectomy was 812 days among the steroid users and 736 days among steroid non-users. Significantly less proportion of intranasal steroid users experienced a repeat polypectomy compared to steroid non-users. This difference was consistent among subgroups of females and concomitant rhinitis treatments users. Patients with post polypectomy intranasal steroid use showed lower risk for a repeat polypectomy compared to steroid non-users. Concomitant rhinitis medication users showed a higher risk whereas other confounders were not significant. CONCLUSIONS: Intranasal steroids were effective in delaying a repeat polypectomy. However, further research using a prospective design is necessary to quantify the benefit of ongoing steroid treatment.
Preservation of the nasolacrimal duct during endoscopic medial maxillectomy for sinonasal inverted papilloma
Authors: Nakamaru Y. , Furuta Y. , Takagi D. , Oridate N. , Fukuda S.
Published: May 2021

BACKGROUND: To assess the efficacy of a new endonasal medial maxillectomy technique (EMM) for the treatment of inverted papilloma (IP). METHODOLOGY: A prospective series of 55 consecutive patients diagnosed with IP between March 2002 and April 2009 were entered into this study. The new surgical technique was applied to tumors arising from the anterior part of the maxillary sinus. After conventional EMM, the entire nasolacrimal duct was separated from the bony component of the nasolacrimal canal and preserved. Schirmer`s test and a visual analog scale (VAS) score were used to assess the lacrimal duct function after surgery. RESULTS: Ten of the 55 patients underwent the new surgical procedure. All patients were categorized with stage T3 or T4 tumors. No patients suffered tumor recurrence. There was no difference in lacrimal duct function between the diseased side and healthy side of the nasolacrimal duct. The mean VAS score was 2.8/100. CONCLUSIONS: This new surgical technique preserves the whole length of the nasolacrimal unit. It also offers several advantages including good visualization, nasolacrimal function after surgery and fewer adverse effects such as facial numbness and epiphora.
The effect of smoking on physiological decongestion of the nasal mucosa in human
Authors: Thorold H. , Bende M.
Published: May 2021

BACKGROUND: Exercise is known to decongest the nasal mucosa which results in increased nasal patency. In a recent study it was suggested that smoking might influence the effect of exercise on the nasal mucosa. This implies that smoking may cause neurological damage to the normal nasal physiology, which has not previously been shown. The aim of this study was to investigate whether there was a difference in nasal mucosal reaction to exercise between smokers and non-smokers. METHODOLOGY: Forty-two smokers and non-smokers underwent acoustic rhinometry to register nasal geometry before and after cycling on an ergometer cycle. A structured interview was used for questions about smoking habits and airway symptoms. RESULTS: Both smokers and non-smokers had a significant increase in MCA (minimal cross-section area) and total nasal volume after exercise. There was no statistical significant difference between smokers and non-smokers. CONCLUSIONS: Smoking does not seem to affect the normal physiological decongestion of the nasal mucosa after exercise.
Nasal obstruction and smell impairment in nasal polyp disease: correlation between objective and subjective parameters
Authors: Hox V. , Bobic S. , Callebaux I. , Jorissen M. , Hellings P.W.
Published: May 2021

Background: Chronic rhinosinusitis with nasal polyposis (NP) represents an invalidating disorder that causes mainly nasal blockage and loss of smell. The aim of this study is to investigate correlations between individual subjective and objective parameters of stable NP disease. Methods: 65 NP patients scored their sinonasal symptoms on a visual analogue scale (VAS) and questionnaires (SNOT-22 and SF-36). Peak nasal inspiratory flow (PNIF) measurement, Sniffinatm Sticks (SS) smell test, blood analysis for eosinophilia, total IgE and culture for Staphylococcus aureus (SA) were performed. Results: VAS scores for nasal blockage correlated with the SNOT-22 and SF-36 scores, which was not observed for VAS of other symptoms. VAS scores for nasal blockage correlated well with PNIF values as well as VAS scores for smell dysfunction and SS results (both p<0.001). NP size correlated with VAS scores for nasal blockage (p<0.01) but not with VAS for other symptoms. NP size showed an inverse correlation with PNIF and SS scores (both p<0.05). Blood eosinophilia correlated with subjective smell reduction (p<0.05). The presence of SA or total IgE levels were not associated with symptoms of NP disease. Conclusion: PNIF and SS are good tools to evaluate symptoms of nasal obstruction and smell reduction in NP disease. Nasal blockage is the only symptom that correlates well with NP size and SNOT-22 scores, whereas smell reduction correlates with blood eosinophilia.
Symptom score questionnaire for nasolacrimal duct obstruction in adults--a novel tool to assess the outcome after endoscopic dacryocystorhinostomy
Authors: Smirnov G. , Tuomilehto H. , Kokki H. , Kemppainen T. , Kiviniemi V. , Nuutinen J. , Kaarniranta K. , Seppa J.
Published: May 2021

BACKGROUND: The incidence of nasolacrimal pathway obstruction increases with age, and dacryocystorhinostomy (DCR) is a commonly applied surgical technique to treat severe cases. However, no disease-specific tools to assess the symptoms and the subjective outcome after DCR have been established. We have developed a specific Nasolacrimal Duct Obstruction Symptom Score (NLDO-SS) questionnaire to evaluate the outcome, and tested it in a prospective clinical trial. STUDY DESIGN: Prospective clinical follow-up study. METHODS: Sixty-eight consecutive primary endoscopic dacryocystorhinostomy (EN-DCR) procedures were performed in 64 patients during 2004-2008. Preoperatively and during the three follow-up visits (at 1 week, 2 and 6 months), the patients filled in the NLDO-SS, and at the second and third follow-up visits they also filled in the Glasgow Benefit Inventory (GBI) questionnaire. At one year after the operation, a GBI questionnaire was sent to the patients. RESULTS: The surgical success rate of EN-DCR was 93 %. EN-DCR resulted in a significant reduction in all of the eight symptoms scores of the NLDO-SS (p= 0.001). The GBI scores indicated a significant benefit at 2 months (+37 (SD; 28) and an even higher benefit at 6 months after surgery (+52 (SD; 29), p= 0.001), but no further improvement was found between 6 and 12 months (+52 vs +52, p= 1.0). The correlation between the total GBI and NLDO-SS was significant (p=0.001). CONCLUSIONS: EN-DCR significantly improves the quality of life as measured by the GBI. The NLDO-SS correlated with the GBI and gave more information about the benefits after EN-DCR than GBI alone. The NLDO-SS proved to be an effective tool to evaluate lacrimal obstructions and EN-DCR benefits. Further studies to validate NLDO-SS are needed.
Physiologic and pathologic septal deviations: subjective and objective functional rhinologic findings
Authors: Gogniashvilli G. , Steinmeier E. , Mlynski G. , Beule A.G.
Published: May 2021

OBJECTIVE: A high incidence of septal deviation with significant inter-rater variability has been reported. An explanation could be the presence of physiological septal deviation besides pathological ones. We differentiated an unselected cohort by their nasal resistance into groups with physiological normal and pathologically increased resistance to detect differences and analogies in comparison to healthy subjects and a pathological cohort. STUDY DESIGN: Prospective cohort study. SETTING: A total of 356 patients were assessed using rhinoresistometry, acoustic rhinometry, endoscopy and visual analogue scales. After definition of a benchmark between physiological and pathological nasal resistance, group differences were calculated and correlations analysed. RESULTS: The normal one-sided inspiratory nasal resistance was defined as less or equal to 0.35 sPa/cm^3 at a flow-velocity of 250 cm^3/s (R250). Using this benchmark, the unselected group of non-rhinological patients was differentiated into 114 subjects with physiological nasal resistance and 44 with pathological septal deviation. Nasal resistance after decongestion was significantly lower for normal or patients with a physiological septal deviation in comparison to the rhinological one on both nasal sides. Healthy subjects and patients with physiological septal deviation showed similarities in objective rhinological parameters as well as rhinological patients and patients with pathological septal deviation derived from the unselected group of non-rhinological patients. Furthermore, this benchmark of nasal resistance shows significant correlations with subjective assessment of nasal breathing. CONCLUSION: Inspiratory nasal resistance obtained at a flow-velocity of 250 cm^3/s using rhinoresistometry may be useful to distinguish patients with physiological and pathological septal deviation. Correlation with subjective assessment and endoscopic findings is improved.
Patient-reported olfactory function following endoscopic sinus surgery with modified endoscopic Lothrop procedure / Draf 3
Authors: Yip J.M. , Seiberlin K.A. , Wormald P.-J.
Published: May 2021

OBJECTIVES/HYPOTHESIS: The Modified Endoscopic Lothrop procedure (MELP) or Draf 3 is a complex procedure, performed for chronic frontal sinusitis that is refractory to standard functional endoscopic sinus surgery. The procedure involves drilling of the frontal T (formed by the septum and middle turbinate`s attachment to the skull base) onto the olfactory fossa often with exposure of the first olfactory neuron and may affect olfactory function. This study was performed to assess patients` subjective sense of smell following this procedure. STUDY DESIGN: Prospective study of retrospective data. METHODS: Sixty-eight patients, who underwent modified endoscopic Lothrop by the senior author (PJW) between 2003 and 2008, completed a post-operative questionnaire asking about their perception of olfactory function. All patients had their pre-operative subjective sense of smell documented prior to undergoing surgery. Patient records were reviewed for pertinent medical information such as the presence of asthma, aspirin sensitivity and nasal polyps. RESULTS: This study found that the majority of patients reported improvement in their sense of smell post-operatively, while only a small number reported a negative impact on their smell. Thirty-nine patients reported an improvement in their post-operative smell grade. Twenty patients reported no change in their smell grade, while the remaining 9 patients stated that their sense of smell worsened after surgery. No statistically significant correlation was found between patient outcome and the presence of asthma, nasal polyps, or Samter`s triad. CONCLUSIONS: The Modified endoscopic Lothrop procedure/Draf 3 had a positive effect on subjective sense of smell post-operatively in this cohort of patients.
Queering the Nigerian Cinema and Politics of Gay Culture
Authors: Ogheneruro Okpadah Stephen
Published: May 2021

The advocacy for gayism and lesbianism in Nigeria is informed by transnational cultural processes, transculturalism, interculturalism, multiculturalism and globalisation. Although critical dimensions on Lesbian, Gay, Bisexual and Transgender (LGBT) are becoming recurrent subjects in Nigerian scholarship, scholarly works on LGBT, sexual identity and Nigerian cinema remain scarce. Perhaps, this is because of indigenous Nigerian cultural processes. While Chimamanda Adichie, a Nigerian novelist cum socio-political activist, campaigns against marginalisation and subjugation of gays and lesbians and for their integration into the Nigerian cultural system, numerous African socio-cultural and political activists hold a view that is dialectical to Adichie’s. The position of the members of the anti-gay group was further strengthened with the institution of stringent laws against gay practice in Nigeria by the President Goodluck Jonathan led government in 2014. In recent times, the gay, bisexual, transgender and lesbian cultures have been a source of raw material for filmmakers. Some of the thematic preoccupations of films have bordered on questions such as: what does it mean to be gay? Why are gays marginalised? Are gays socially constructed? What is the future of the advocacy for gay and lesbian liberation in Nigeria? Although most Nigerian film narratives are destructive critiques of the gay culture, the purpose of this research is not to cast aspersion on the moral dimension of LGBT. Rather, I argue that films on LGBT create spaces and maps for a critical exploration of the gay question. While the paper investigates the politics of gay culture in Nigerian cinema, I also posit that gays and lesbians are socio-culturally rather than biologically constructed. This research adopts literary and content analysis methods to engage Moses Ebere’s Men in Love with reference to other home videos on the gay and lesbian motifs.
Production of lactic and acetic acids during fermentation of milk fortified with kiwi juice using Saccharomyces boulardii and lactobacilli
Authors: Mousa Ahmed Hassan , Wang Gang , Zhang Hao
Published: May 2021

Purpose: To investigate the synergistic effect of Saccharomyces boulardii and lactobacilli on lactic and acetic acids produced during fermentation of milk fortified with kiwi juice, relative to fermentation of unfortified milk.

Methods: Skimmed milk was fortified with kiwi juice (4 % v/v) and fermented for 12 h at 37 °C by a combination of S. boulardii and lactobacilli strains. Lactic and acetic acids were determined using gas chromatography-mass spectrometry (GS-MS).

Results: The presence of kiwi juice in the milk stimulated the production of lactic (1.35 g/100g) and acetic (0.29 mg/g) by S. boulardii in the absence of lactobacilli. When S. boulardii was inoculated with Lb. casei 20975, the production of lactic acid and acetic acid increased to 2.36 g/100 g and 0.71 mg/g, respectively. Furthermore, acid production increased when Lb. plantarum RS (35-11), Lb. casei LCS, and Lb. plantarum JXJ (6 - 12) were inoculated into milk free of kiwi juice in which S. boulardii was grown. Saccharomyces boulardii resulted in marginal production of acids by Lb. fermentum F9.

Conclusion: These results show that acid production is positively affected by some lactobacilli strains in the milk whether fortified with kiwi juice or free of this juice. However, fermentation of these formulations for a period longer than 6 h may result in losses in acid yield.
Effect of n-3 polyunsaturated fatty acids on dopaminergic neurons in substantia nigra, brain inflammatory response and behavior in mice with Parkinson’s disease
Authors: Zhang Zhaowen , Wang Sisi , Li Chengyan
Published: May 2021

Purpose: To examine the effect of n-3 polyunsaturated fatty acids (PUFAs) on dopaminergic neurons in substantia nigra, intracerebral inflammatory response and ethology in mice with Parkinson’s disease (PD).

Methods: Four groups of male C57BL/6 mice (n = 48) were used: normal control, negative control, n3PUFA, and Madopa groups. Except for normal control group, all groups were given 6- hydroxydopamine hydrochloride (6-OHDA) to establish Parkinson’s mice model. The expressions of tyrosine hydroxylase (TH) and calcium-binding protein (CB) in substantia nigra dopaminergic neurons were determined with immunohistochemistry and Western blot. The contents of nitric oxide (NO), tumor necrosis factor (TNF-α) and interferon γ (IFN-γ) (indices of intracerebral inflammatory response) were measured. Tremor paralysis, moving grid number, standing times, swimming ability, and the number of rollers in each group were observed as indices of ethology.

Results: The number of TH and CB-positive neurons in the substantia nigra of n-3PUFA-treated mice was significantly increased, relative to those in Madopa-treated mice (p < 0.05). The expressions of TH and CB proteins in substantia nigra in n-3PUFA group were markedly higher than the corresponding expressions in Madopa-treated mice (p < 0.05). Decreased levels of NO, TNF-α and IFN-γ levels were seen in 3PUFA group, when compared to mice in Madopa group, but higher behavioral scores were obtained in n-3PUFA-treated mice, relative to Madopa-treated mice (p < 0.05).

Conclusion: The n-3PUFAs protect substantia nigra compact dopaminergic neurons against Parkinson’s disease, alleviate immune inflammation, and improve the coordination of limb movement. Thus, n-3PUFAs have potential therapeutic application in the management of Parkinson’s disease.