bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic and expression variations of cell cycle pathway genes in brain tumor patients
Authors: Naqvi Anum Zehra , Mahjabeen Ishrat , Ameen Saima , Ahmed Malik Waqar , Khan Asad Ullah , Akram Zertashia , Kayani Mahmood Akhtar
Published: May 2020

The present study was designed to determine the association between the genetic polymorphisms/expression variations of RB1 and CCND1 genes and brain tumor risk. For this purpose, 250 blood samples of brain tumor patients along with 250 controls (cohort I) and 96 brain tumor tissues (cohort II) with adjacent control section were collected. Mutation analysis of RB1 (rs137853294, rs121913300) and CCND1 (rs614367, rs498136) genes was performed using ARMS-PCR followed by sequencing, and expression analysis was performed using real-time PCR and immunohistochemistry. The results showed homozygous mutant genotype of RB1 gene polymorphism, rs121913300 (P=0.003) and CCND1 gene polymorphism rs614367 (P=0.01) were associated significantly with brain tumor risk. Moreover, significant down-regulation of RB1 (P=0.005) and up-regulation of CCND1 (P=0.0001) gene was observed in brain tumor sections vs controls. Spearman correlation showed significant negative correlation between RB1 vs proliferation marker, Ki-67 (r = −0.291*, P<0.05) in brain tumors. Expression levels of selected genes were also assessed at protein level using immunohistochemical analysis (IHC) and signification down-regulation of RB1 (P=0.0001) and up-regulation of CCND1 (P=0.0001) was observed in brain tumor compared with control sections. In conclusion, it is suggested that polymorphisms/expression variations of RB1 and CCND1 genes may be associated with increased risk of brain tumor.
Research on control strategies for ankle rehabilitation using parallel mechanism
Authors: Li Jianfeng , Fan Wenpei , Dong Mingjie , Rong Xi
Published: May 2020

For patients with ankle injuries, rehabilitation training is an important and effective way to help patients restore their ankle complex's motor abilities. Aiming to improve the accuracy and performance of ankle rehabilitation, the authors focus on the control strategies of the developed parallel ankle rehabilitation robot with novel 2‐UPS/RRR mechanism. Firstly, the kinematics model of the mechanism is established, and they deduce the inverse solution of positions as well as the velocity mapping between the driving speed and the robot's angular velocity, based on which they realise the trajectory tracking control in the process of passive rehabilitation training. Secondly, they set up experiments to determine the torque threshold that can be used to detect the motion intention of ankle joint, and then they propose the active rehabilitation training strategy according to the motion intention detection. Finally, experiments were carried out with healthy subjects, with results showing that the trajectory tracking error during passive rehabilitation training is very small, and the moving platform of the ankle rehabilitation robot can drive the ankle joint to the detected motion intention direction at a constant speed flexibly and smoothly, which verifies the effectiveness of the control strategies for ankle rehabilitation training.
Filtering Doherty power amplifier
Authors: Qi Xiaobo , Xiao Fei
Published: May 2020

At present, it is a trend in wireless communication to integrate conventional separate components into a single one for further miniaturisation and whole performance optimisation. In this study, a novel filtering Doherty power amplifier topology is proposed, which incorporates a bandpass power divider for power division. The power divider is characterised by third‐order bandpass response and good out‐of‐band performance, and then it can purify the input spectrum for the whole amplifier. For demonstration, an example of this filtering Doherty power amplifier at 2.0 GHz was designed, fabricated and measured. The measured results show that at least 21 dB of the out‐of‐band suppression is obtained up to fourth harmonic for purifying the input spectrum. Meanwhile, high back‐off efficiency is still retained for this filtering Doherty power amplifier.
High-speed stars: Galactic hitchhikers
Authors: Caffau E. , Monaco L. , Bonifacio P. , Sbordone L. , Haywood M. , Spite M. , Di Matteo P. , Spite F. , Mucciarelli A. , François P. , Matas Pinto A. M.
Published: May 2020

Context.The search for stars born in the very early stages of the Milky Way star formation history is of paramount importance in the study of the early Universe since their chemistry carries irreplaceable information on the conditions in which early star formation and galaxy buildup took place. The search for these objects has generally taken the form of expensive surveys for faint extremely metal-poor stars, the most obvious but not the only candidates to a very early formation.

Aims.Thanks toGaiaDR2 radial velocities and proper motions, we identified 72 bright cool stars displaying heliocentric transverse velocities in excess of 500 km s−1. These objects are most likely members of extreme outer-halo populations, either formed in the early Milky Way build-up or accreted from since-destroyed self-gravitating stellar systems.

Methods.We analysed low-resolution FORS spectra of the 72 stars in the sample and derived the abundances of a few elements. Despite the large uncertainties on the radial velocity determination, we derived reliable orbital parameters for these objects.

Results.The stars analysed are mainly slightly metal poor, with a few very metal-poor stars. Their chemical composition is much more homogeneous than expected. All the stars have very eccentric halo orbits, some extending well beyond the expected dimension of the Milky Way.

Conclusions.These stars can be the result of a disrupted small galaxy or they could have been globular cluster members. Age estimates suggest that some of them are evolved blue stragglers, now on the subgiant or asymptotic giant branches.
Flotation enrichment of resistant gold ores
Authors: Askarova Gulzhan , Shautenov Mels , Nogaeva Kulzhamal
Published: May 2020

Ores of the Vasilkovsky deposit include arsenopyrite, pyrite, pyrrhotite, marcasite, gold, chalcopyrite, sphalerite, galena, faded ore (tennantite)S, bismuthine, native bismuth, lellingite, molybdenite, cubanite, bornite, antimonite, relict minerals, magnetite, apatite and apatite chromite, sericite, chlorite, potassium feldspar, tourmaline), quartz, carbonates (siderite, ankerite, calcite), fluorite, barite. Arsenopyrite is the main ore mineral. It contains the bulk of gold, as well as impurities - copper, cobalt, nickel, bismuth, zirconium, titanium, lead, zinc, antimony, silver, molybdenum. Bismuth and its minerals are widespread, they are constantly associated with arsenopyrite, forming intergrowths with native gold, less often with chalcopyrite and faded ore. Native gold is distributed very unevenly, forms the finest precipitates ranging in size from tenths of a micron to 0.063 mm, grows together with quartz, arsenopyrite, pyrite and bismuth minerals. Rich ores were formed by combining bismuthcontaining associations with arsenopyrite. The role of gold in arsenopyrite increases with depth. Ores are of the gold-quartz-sulfide type. Quartz in ore up to 90 %, sulfides from 3 to 5 %. The content of harmful impurities (arsenic) reaches 2 % or more. Ores are refractory, require special technology for the beneficiation and extraction of gold.
Increasing of filtration characteristics of ore bodies in borehole uranium mining
Authors: Rakishev Bayan , Kenzhetayev Zhiger , Shampikova Asel , Toktaruly Bakytzhan
Published: May 2020

There is a description of technology by borehole uranium mining in Kazakhstan. The factors which affect for reduction of filtration characteristics in productive reservoirs are studied in detail and described an effective method for increasing borehole uranium production. The processes that occur during borehole mining of uranium with the use of sulfuric acid as solvent, as well as the conditions and reasons for reducing the productivity of geotechnical wells during their operation are considered. The results of experimental work on the intensification of borehole uranium mining in complex mining and geological conditions are analyzed and discussed, comparative graphs of the content of uranium in the productive solution, the flow rate of wells, the degree of extraction and the volume of production before and after the experiments are constructed. The results of experimental work on the efficiency of borehole uranium production, the content of uranium in PS and the productivity of wells, with predominance of the chemical type of sedimentation, are positively evaluated. The optimal parameters for the intensification of borehole uranium production in complex mining and geological conditions are recommended, and method for using complex of multi-purpose chemical reagents in combination with traditional methods of well regeneration is developed.
Improving the effectiveness of explosives using a dispersed air gap
Authors: Tukhtamov Ilyar , Beisebaev Nurken , Bazhanov Bulat , Orynbay Asfandiyar , Shampikova Asel
Published: May 2020

Various foreign companies produce a wide range of watercontaining explosive mixtures. Gelatinized suspension and water-gel mixtures are patronized in polyethylene packaging of different diameters, various energy additives are introduced, their density and volume concentration of energy are regulated over a wide range. Kazakhstan became one of the sovereign large mining countries of the world after gaining independence in 1991. The mining industry forms the basis of industry, the economy of the country as a whole. It achieved this situation through mining mainly by the open method (more than 70 %).
Geotechnical analysis of optimal parameters for foundations interacting with loess area
Authors: Dubinchyk Olha , Bannikov Dmytro , Kildieiev Vitalii , Kharchenko Vitalii
Published: May 2020

The article highlights results of the geotechnical analysis of the stress and strain state for the base of a subsoil massif under its interaction with the strip foundations. The massif is represented by loess soils which while soaking give overtime subsidences that complicate the operation of a building or a structure. Through geotechnical iterative research, optimization of the parameters for strip foundations on four axes at a four-storeyed residential building is carried out. Checks are performed on two groups of limiting states for scenarios of soil occurrence in natural, moistened and compacted states. The optimum dimensions in the width of strip foundations are selected, they give approximately the same strain values of the base after the creation of the soil bedding with its layer-bylayer compaction. The relevance of this research is to develop optimal parameters in the design of strip foundations for shallow depth on subsidental loess soils.
The new approach in evaluating the mechanism of the blast effect and organizing the blasting operations while tunneling
Authors: Petrenko Volodymyr , Tiutkin Oleksii , Heletiuk Ihor , Tkach Taisiia
Published: May 2020

It is relevant for the organization of blasting operations with consideration to the mechanism of blast effect to justify new provisions due to the emergence of new explosives, means of initiating charges and instrumental measurement of parameters. In view of this, a new approach is needed for evaluating the mechanism of blast effect in the combined application of short-delay and delay-action blastings with a high level of organization and safety. Analyzing the results in the justification of the short-delayed blasting, obtained by many researchers in recent decades, its main advantages and some limitations in its evaluation have been identified. A clear justification for the combined application under seismic safety is provided. New results to explain the mechanism of the blast effect in the combined application of short-delay and delay-action blastings at tunneling facilities have been obtained. They help in the seismic action reduction under the conditions of close city development. Methodological approaches to organize blasting operations at complex facilities in Ukraine implemented during tunneling have been developed.
Studying the features of the implementation of underground coal gasification technology in terms of Lvivvuhillia SE
Authors: Saik Pavlo , Dychkovskyi Roman , Lozynskyi Vasyl , Falshtynskyi Volodymyr , Cabana Edgar , Hrytsenko Leonid
Published: May 2020

Topical issues of the possibilities for changes in the coal extraction technology in terms of Stepova mine of Lvivvuhillia SE have been highlighted. Analysis of the current state of mining operations has been carried out. Design solutions as for introduction of the coal gasification technology in the life cycle of the mining enterprise has been proposed on the basis of the analytical, experimental, and industrial studies; the technology has been described. Percentage ratio of the output of combustion generator gases (Н2, СО, СН4) has been identified; gas combustion value and efficiency of the process depending on certain changes in the blowing mixture composition supplied into the underground gas generator have been determined. Heat balance of the process of underground coal gasification has been studied making it possible to evaluate its energy balance. The algorithm to determine coal reserves in a mine pillar to be gasified has been proposed. Indices of the output of combustion generator gases from the gasification column have been defined. The relevant issues have been studied of ensuring the possibility of underground coal gasification technology when uncovering the mining extracted area for the underground gas generator operation.
Conversion of gas engine waste heat into cold using absorption chillers
Authors: Karman Georgii , Oksen Yurii , Trofymova Olena , Komissarov Yurii , Dizhevskyi Borys , Radiuk Maksym , Diakun Inna
Published: May 2020

A possibility of gas engine waste heat conversion into cold for air conditioning in mines using lithium bromide absorption chillers is investigated. Dependencies of parameters of a thermodynamic cycle and energy indicators of chillers on temperatures of a heating medium and a coolant are obtained using mathematical modelling. It is shown that it is rational to use two chillers with sequential movement of a heating medium and a coolant through them in opposite directions for a full conversion of gas engine waste heat. COP of such a system is 0.733. This allows obtaining 2140 kW of cooling capacity with a coolant temperature of 7 °C when using a gas engine JMS-620 by Jenbacher.
Outburst cavity formation in the working face driven along the outburst-prone coal seam
Authors: Krukovskyi Oleksandr , Krukovska Viktoriia , Zhang Wen
Published: May 2020

In Donbas coal mines, coal and gas outbursts present a major risk for the mining operation safety. Rapidly released energy can cause serious damage to the mine’s personnel and production equipment. Modern numerical methods allow modeling complex physical processes occurred during the coal and gas outbursts. The mathematical model was developed for the coupled processes of the rock massif deformation and gas filtration in the mine face near the tectonic dislocation. When solving the problem, the finite element method was used. The calculation results of the stresses, inelastic deformation zones, pressures of methane and configuration of cavity of the coal and gas outburst are represented in the paper. It is shown that an outburst cavity is formed inside the coal seam and is bounded from above and from below by the host rocks. The calculated geometry of the fracture cavity at the gas-dynamic phenomena in the mine working face coincides with actual data obtained in the mines of Donbas and, therefore, confirms the adequacy of the developed mathematical model.
Complex spectral-acoustic monitoring of the state of fluid-saturated coal-rock mass
Authors: Pylypenko Yurii , Konstantynova Iryna , Оzet Kchichtof
Published: May 2020

Subject of the research is the methods for monitoring properties and state of coal-rock massif. This work is an experimental validation of the studied parameters of acoustic emission occurred during destruction of the roadway roof. Elements of the theory of acoustic emission control, research methods, results and experimental studies of the fluid-saturated rock destruction were studied. In this article, methods of studying and interpreting the results of geophysical observations of the process of the roof rock stratification and fall at caving of the undermined rocks at a complex stressed state are presented. Biseds, approaches to solving the problems of managing and controlling the dynamics of changes in the stress-strain state of the undermined fluid-saturated coal-rock massif based on factors of autocorrelation between the seismic-acoustic phenomena occurred over time are described. Experimental grounds are given to the complex control methods with determination of the level of disintegration by the Fourier estimation of the amplitude-frequency and amplitude-time spectra.
Redistribution and realization of energy at different scale-hierarchical levels of coalrock massif
Authors: Sielski Anna , Bezruchko Kostiantyn , Pymonenko Liudmyla , Burchak Oleksandr , Karhapolov Andrii , Baranovskyi Volodymyr
Published: May 2020

The research of redistribution and realization of energy at different scale-hierarchical levels at the Donbas coalrock massif based on the parameters of faultings and gas-dynamic phenomena has been conducted. It is proved that the energy transfer, incoming by impulses in post-inversion time of the geological development in Donbas, occurs throughout the whole structure of coal, due to the formation of energy connection between individual elements of the molecular structure. This process is accompanied by transition of free energy into a bound state with increase in ordering of the molecular structure and aromaticity of the coal substance (local increase in the degree of catagenetic transformations). The conditions of energy accumulation and realization depend on the peculiarities of molecular processes occurring in dislocations of different types. Less energy is accumulated in tensile zones than in compression zones, which is confirmed by the intensity of coal and gas outbursts. It has been established that the energy entering the multifractal geological environment in Donbas from external sources is also redistributed fractionally by the system, causing the formation of multiscale discrete inhomogeneities, which provides the massif with specific properties and ability to self-organization. A fractal model of the structure of the coalrock massif is proposed.
Ordered assembling of Co tetra phenyl porphyrin on oxygen-passivated Fe(001): from single to multilayer films
Authors: Calloni Alberto , Jagadeesh Madan S. , Albani Guglielmo , Goletti Claudio , Duò Lamberto , Ciccacci Franco , Bussetti Gianlorenzo
Published: May 2020

Tetra-phenyl prophyrins (TPP) are an interesting class of organic molecules characterized by a ring structure with a metal ion in their centre. An ordered growth of such molecules can be obtained even on metallic substrates by means of a proper modification of the reactive interface, as we demonstrated for ZnTPP molecules coupled to oxygen-passivated Fe(001) [G. Bussetti et al. Appl. Surf. Sci. 390, 856 (2016)]. More recently, we focused on CoTPP molecules, characterized by a not nil magnetic moment and therefore of potential interest for magnetic applications. As in the ZnTPP case, our results for one monolayer coverage report the formation of an ordered assembly of flat-lying molecules. However, some differences between the two molecular species are observed in the packing scheme and in the degree of electronic interaction with the substrate. With the aim of reaching, also for CoTPP, a comprehensive view of molecular organization on Fe, we complement here our previous investigations by following the growth of the CoTPP film for increasing coverage, showing that an ordered stacking of such molecules is indeed realized at least up to four molecular layers.
2-methyloxolane as alternative solvent for lipid extraction and its effect on the cactus (Opuntia ficus-indicaL.) seed oil fractions
Authors: Gharby Said , Ravi Harish Karthikeyan , Guillaume Dominique , Abert Vian Maryline , Chemat Farid , Charrouf Zoubida
Published: May 2020

The potential of 2-methyloxolane (2-MeO) as an alternative solvent to extract cactus seed oil was compared, in qualitative and quantitative terms, with that of n-hexane, a solvent commonly used for the extraction of edible or cosmetic oils. With 2-MeO, the oil yield was higher (9.55 ± 0.12 g/100 g) than the oil extracted with n-hexane (8.86 ± 0.25 g/100 g). The chemical and physical parameters quality indices (acidity, peroxide value and extinction coefficients (K232and K270) of 2-methyloxolane extracted oil were found to be much higher than that of oil extracted with n-hexane. A suitable refining scheme will have to be applied, probably leading to slight additional cost and losses. Also, the results showed that the sterol content was higher in the oil obtained with 2-MeO (111.5 ± 2.5 mg/100 g) as a solvent when compared to the oil extracted with n-hexane (102.1 ± 7.54 mg/100 g). However, fatty acid and tocopherol content were not influenced by the extraction solvent. Therefore, the bio-based solvent 2-methyloxolane can be considered as an excellent alternative to the petroleum-based solvent n-hexane for edible/cosmetic oil extraction. The utilization of 2-MeO for oil extraction can drastically reduce the health and environmental impacts associated with n-hexane.
Toxocara infection: seroprevalence and associated risk factors among primary school children in central China
Authors: Wang Shuai , Li Haoran , Yao Zhijun , Li Pengju , Wang Dong , Zhang Haizhu , Xie Qing , Zhang Zhenchao , Li Xiangrui
Published: May 2020

Toxocariasis is a zoonotic disease that poses a threat to public health worldwide. In the present study, we investigated the seroprevalence of Toxocara infection among primary school children in Henan province, central China, which was previously unknown. Sera from 2451 primary school children were collected from September 2015 to October 2018, and evaluated for anti-Toxocara antibodies by enzyme-linked immunosorbent assay (ELISA). The overall seroprevalence of Toxocara infection was 5.14% (126/2451). The main risk factors related to Toxocara infection identified in this study were the age of children, residence area of children, contact with cats or dogs, and exposure to soil. Hand washing before eating was considered to be a protective factor. These findings demonstrate that Toxocara infection is relatively common among primary school children in Henan province.
Interaction morphology and bond strength of nanofilled simplified-step adhesives to acid etched dentin
Authors: Hipólito Vinicius Di , Reis André Figueiredo , Mitra Sumita B , de Goes Mario Fernando
Published: May 2020

Objective: To evaluate the effect of nanofillers incorporated into adhesives on the microtensile bond strength (μ-TBS) and interfacial micromorphology to dentin.

Methods: The occlusal enamel of 5 human molars was removed and each tooth sectioned into four quarters. The exposed dentin was treated with one of the following adhesives: Adper Single Bond (SB-unfilled), OptiBond Solo Plus (OS-barium aluminoborosilicate, 400nm Ø), Prime & Bond NT (NT-colloidal silica, 7-40 nm Ø) and Adper Single Bond 2 (SB2-colloidal silica, 5nm Ø). Cylinders of resin-based composite were constructed on the adhesive layers. After 24-hour storage, the restored tooth-quadrants were sectioned to obtain stick-shaped specimens (0.8 mm2, cross-sectional area) and submitted to μ-TBS at a cross-speed of 0.5 mm/min. Data were analyzed using one-way ANOVA and Tukey’s test (alpha = .05). Twenty-eight additional teeth were used for interfacial micromorphologic analysis by SEM (16-teeth) and TEM (12-teeth). The dentin surfaces of 32 discs were treated with the adhesives (8 discs for adhesive) and laminated to form disc-pairs using a flowable resin composite for SEM/EDS analysis. For TEM, 90nm-thick nondemineralized unstained sections were processed.

Results: SB2 showed significant higher bond strength than SB, OS and NT. The SEM/EDS and TEM analysis revealed nanofillers infiltrated within the interfibrillar spaces of the SB2-hybrid layer. Fillers were concentrated around patent tubular orifices and in the adhesive layer for OS and NT.

Conclusion: The presence of nanofillers within the interfibrillar spaces of the SB2-hybrid layer suggests its importance in the improvement of the μ-TBS. (Eur J Dent 2012;6:349-360)
Parental knowledge and attitudes regarding the emergency treatment of avulsed permanent teeth
Authors: Ozer Sezin , Yilmaz Elif Ipek , Bayrak Sule , Tunc Emine Sen
Published: May 2020

Objective: The aim of this study was to examine parental knowledge and attitudes about avulsed permanent teeth and their emergency treatment in children.

Methods: A total of 289 parents of children aged 6-12 years receiving care at the Ondokuz Mayis University Pediatric Dentistry Clinic were included in the study. Questionnaires were used to collect data on parents’ demographic characteristics, previous training in traumatic dental injury and treatment and knowledge of avulsed permanent teeth and their emergency management. Chi-square tests were used to identify differences in responses for different variables.

Results: More than half of the participating parents were female (69.6%) and between the age of 30-39 years (64.4%). Most (90.7%) reported that they would not replant the avulsed tooth in its socket, and most (68.2%) gave correct answers regarding the optimum time for which an avulsed tooth should be left out of the mouth prior to replantation. However, most parents were not sufficiently informed about the appropriate method for cleaning a dirty avulsed tooth or transporting it to a dentist or doctor. None of the demographic characteristics or training status was found to have a statistically significant effect on the number of correct responses regarding appropriate management of avulsion injuries (P>.05)

Conclusion: This study revealed that the parental level of knowledge about the emergency treatment of avulsion in children is inadequate and that educational campaigns are necessary to improve proper emergency management of dental avulsion. (Eur J Dent 2012;6:370-375)
Apical third enlargement of the root canal and its relationship with the repair of periapical lesions
Authors: Souza Ronaldo Araújo , Dantas João Costa Pinto , Brandão Paula Maciel , Colombo Suely , Lago Maurício , Duarte Marco Antônio Húngaro
Published: May 2020

Objective: The purpose of this study was to evaluate if the apical third enlargement of root canal is the determinant factor for the repair of periapical lesions in endodontic treatment.

Methods: Eighty upper and lower incisors, canines and premolars with periapical lesions were randomly divided in 2 groups and were treated by undergraduate students. Canals were instrumented with up to 3 files in group I (n = 40) and up to 4 files in group II (n = 40) 1 mm short of the apex and were filled with a calcium hydroxide dressing. After removing calcium hydroxide 14 days later, both groups were filled using the lateral condensation technique. In the 2-year follow-up, a few patients did not return, and some cases did not present conditions for accurate comparisons. Therefore, only 43 patients (24 in group I and 19 in group II) presented conditions for radiographic comparisons. Data were statistically analyzed using Fisher's exact test.

Results: Comparison of the initial and follow-up radiographs showed that 22 out of 24 (91.67%) patients in group I and 17 out of 19 patients (89.47%) in group II showed repair. Statistical analysis revealed no significant differences between the groups (P>.05).

Conclusion: The results of this study show that the apical third enlargement did not alter the outcome of endodontic treatment of teeth with periapical lesion performed by undergraduate students. (Eur J Dent 2012;6:385-388)
Can extended photoactivation time of resin-based fissure sealer materials improve ultimate tensile strength and decrease water sorption/solubility?
Authors: Borges Boniek Castillo Dutra , Souza-Júnior Eduardo José , Catelan Anderson , Sartini Paulillo Luís Alexandre Maffei , Aguiar Flávio Henrique Baggio
Published: May 2020

Objective: This study aimed to evaluate the impact of extended photoactivation time on ultimate tensile strength (UTS), water sorption (WS) and solubility (WSB) of resin-based materials used as fissure-sealants

Methods: A fissure-sealant (Fluroshield) and a flowable composite (Permaflo) polymerized for 20 and 60 seconds were tested. For UTS, 20 hourglass shaped samples were prepared representing two materials and two photoactivation time (n=5). After 24-h dry-storage, samples were tested in tension using a universal testing machine at a cross-head speed of 0.5 mm/min (UTS was calculated in MPa). For WS and WSB, 20 disks with 5 mm diameter and 1 mm height (n=5) were prepared and volumes were calculated (mm3). They were transferred to desiccators until a constant mass was obtained (m1) and were subsequently immersed in distilled water until no alteration in mass was detected (m2). Samples were reconditioned to constant mass in desiccators (m3). WS and WSB were determined using the equations m2-m3/V and m1-m3/V, respectively. Data were subjected to twoway ANOVA and Tukey’s HSD test (P<.05).

Results: There was no significant difference between materials or photoactivation times for the UTS and WS. Permaflo presented lower but negative WSB compared to Fluroshield.

Conclusions: Extended photoactivation time did not improve the physical properties tested. Fluroshield presented physical properties that were similar to or better than Permaflo. (Eur J Dent 2012;6:402-407)
In vitro antibacterial effects of glassionomer cement containing ethanolic extract of propolis on Streptococcus mutans
Authors: Topcuoglu Nursen , Ozan Fatih , Ozyurt Mustafa , Kulekci Guven
Published: May 2020

Objective: The aim of this study was to evaluate the antibacterial property of glass-ionomer cement (GIC) containing propolis against Streptococcus mutans and its effect on the in vitro S. mutans biofilm formation.

Methods: Ethanolic extract of propolis (EEP) was prepared at two concentrations as 25 and 50%. Three different experimental GIC disks were prepared using pure liquid and liquid solutions diluted with 25 and 50 percent of EEP concentrations. Minimum inhibitory concentration (MIC) of EEP on the growth of S. mutans ATCC 25175 was determined by using agar dilution method. Agar diffusion test and an in vitro S. mutans biofilm assay for GIC disks with and without EEP were performed

Results: MIC values of Turkish propolis for S. mutans ATCC 25175 was found as 25 μg/mL. Experimental GICs containing propolis exhibited inhibition zones and their dry biofilm weights were less than the pure GIC. The bacterial density was lower in the GIC containing 50% EEP.

Conclusions: A distinct antibacterial and antibiofilm efficacy of propolis containing GIC on S. mutans has been observed. Although further research is needed to show clinical results, antibacterial GIC containing propolis would be a promising material for restoration. (Eur J Dent 2012;6:428-433)
Facile C–S Bond Cleavage of Aryl Sulfoxides Promoted by Brønsted Acid
Authors: Maulide Nuno , Brutiu Bogdan R. , Klose Immo
Published: May 2020

A method for the Brønsted acid promoted desulfination of aryl sulfoxides is presented. In the presence of a thiol, electron-rich sulfoxides undergo C–S bond cleavage to give the corresponding protodesulfinated arenes and disulfides.
Infected Pancreatic Hydatid Cyst with Cysto-Pancreatic Fistula Presenting as Acute Pancreatitis
Authors: Daniel Phillip , Shukla Siddharth , Prabhakar Nidhi , Kulkarni Aditya , Sharma Ravi , Gupta Rajesh , Rana Surinder Singh
Published: May 2020

Hydatid cysts can be found in almost any organ of the body with the most common sites being liver, lung, spleen, and kidney. A pancreatic hydatid cyst is rare but an isolated pancreatic hydatid cyst is even rarer. Cysts in the head of pancreas usually present with jaundice, whereas cysts located in the body and tail are usually asymptomatic. We present a rare case of isolated pancreatic hydatid cyst that presented with acute pancreatitis and mimicked a pancreatic fluid collection.
Combination of Oral Anticoagulants and Single Antiplatelets versus Triple Therapy in Nonvalvular Atrial Fibrillation and Acute Coronary Syndrome: Stroke Prevention among Asians
Authors: Santoso Anwar , Raharjo Sunu B.
Published: May 2020

Atrial fibrillation (AF), the most prevalent arrhythmic disease, tends to foster thrombus formation due to hemodynamic disturbances, leading to severe disabling and even fatal thromboembolic diseases. Meanwhile, patients with AF may also present with acute coronary syndrome (ACS) and coronary artery disease (CAD) requiring stenting, which creates a clinical dilemma considering that majority of such patients will likely receive oral anticoagulants (OACs) for stroke prevention and require additional double antiplatelet treatment (DAPT) to reduce recurrent cardiac events and in-stent thrombosis. In such cases, the gentle balance between bleeding risk and atherothromboembolic events needs to be carefully considered. Studies have shown that congestive heart failure, hypertension, age ≥ 75 years (doubled), diabetes mellitus, and previous stroke or transient ischemic attack (TIA; doubled)–vascular disease, age 65 to 74 years, sex category (female; CHA2DS2-VASc) scores outperform other scoring systems in Asian populations and that the hypertension, abnormal renal/liver function (1 point each), stroke, bleeding history or predisposition, labile international normalized ratio (INR), elderly (>65 years), drugs/alcohol concomitantly (1 point each; HAS-BLED) score, a simple clinical score that predicts bleeding risk in patients with AF, particularly among Asians, performs better than other bleeding scores. A high HAS-BLED score should not be used to rule out OAC treatment but should instead prompt clinicians to address correctable risk factors. Therefore, the current review attempted to analyze available data from patients with nonvalvular AF who underwent stenting for ACS or CAD and elaborate on the direct-acting oral anticoagulant (DOAC) and antiplatelet management among such patients. For majority of the patients, “triple therapy” comprising OAC, aspirin, and clopidogrel should be considered for 1 to 6 months following ACS. However, the optimal duration for “triple therapy” would depend on the patient's ischemic and bleeding risks, with DOACs being obviously safer than vitamin-K antagonists.
Prosthetic Reconstruction of the Maxilla and Palate
Authors: Pool Christopher , Shokri Tom , Vincent Aurora , Wang Weitao , Kadakia Sameep , Ducic Yadranko
Published: May 2020

Maxillary defects commonly present following surgical resection of oncologic processes. The use of rotational and free flaps has largely replaced the use of prosthetic options for hard palate and maxillary reconstruction, but prostheses remain a useful tool. Prosthetic devices may be invaluable in patients considered poor candidates for surgical reconstruction secondary to poor vascularity, need for postoperative radiation, or medical comorbidities that place them at high risk for healing following reconstruction. Obturators may also be considered over soft tissue options if oncologic surveillance via direct visualization of the surgical site is warranted.
Visiting Student Away Rotations in Ophthalmology: A Study of Medical Students' Experiences and Perspectives
Authors: Patel Sunny B. , Kelly Lisa D.
Published: May 2020

Background Despite the frequency of medical students' participation in ophthalmology clerkships away from their home institution, the impact and benefit of these clerkships have remained uninvestigated. To date, no study has focused specifically on medical student perspectives of away ophthalmology clerkships.

Objective The purpose of the study was to evaluate the medical students' perspectives on and experience with away rotations in ophthalmology, and assess their effect on residency Match outcomes.

Methods An anonymous, original, online survey was designed and distributed to applicants of the 2015 to 2018 ophthalmology Match cycles.

Results A total of 69 responses from nine medical institutions were collected (62% response rate). Forty-one respondents (59%) chose to perform at least one away rotation. Among away rotators, the mean number performed was 1.44. Thirty-seven away rotators (90%) reported receiving an interview from at least one host institution they visited. The average estimated cost of an away rotation was ∼1,709 U.S. dollars. With a 95.7% overall match rate among the respondents, no statistically significant difference was seen in match rates between away rotators and nonaway rotators (p = 0.564). Among the away rotators, the mean position on their rank order list matched was 2.34, while the nonaway rotators matched at a mean position of 2.13 (p = 0.383).

Conclusion No association between away participation and success in the San Francisco Match was observed in this study. However, study participants did experience non-Match-related benefits from away elective participation.
Reconstruction of the Midface and Palate
Authors: Bender-Heine Adam , Wax Mark K.
Published: May 2020

The midface is a complex anatomic structure that is fundamental to many physiologic and homeostatic functions. It may be involved in many pathologic processes that require partial or complete removal. When this happens, reconstruction is mandatory to improve cosmetic outcome with its effect on social interaction as well as to provide an opportunity for complete orodental rehabilitation with restoration of all physiologic functions. This article will review the different reconstructive options available for complex defects of the maxillofacial complex. It will highlight the surgical options available to maximize functional restoration. Finally, it will discuss computer modeling to optimize reconstructive planning.
Role of Factor XIa and Plasma Kallikrein in Arterial and Venous Thrombosis
Authors: Visser Mayken , Heitmeier Stefan , ten Cate Hugo , Spronk Henri M. H.
Published: May 2020

Cardiovascular disease, including stroke, myocardial infarction, and venous thromboembolism, is one of the leading causes of morbidity and mortality worldwide. Excessive coagulation may cause vascular occlusion in arteries and veins eventually leading to thrombotic diseases. Studies in recent years suggest that coagulation factors are involved in these pathological mechanisms. Factors XIa (FXIa), XIIa (FXIIa), and plasma kallikrein (PKa) of the contact system of coagulation appear to contribute to thrombosis while playing a limited role in hemostasis. Contact activation is initiated upon autoactivation of FXII on negatively charged surfaces. FXIIa activates plasma prekallikrein (PK) to PKa, which in turn activates FXII and initiates the kallikrein–kinin pathway. FXI is also activated by FXIIa, leading to activation of FIX and finally to thrombin formation, which in turn activates FXI in an amplification loop. Animal studies have shown that arterial and venous thrombosis can be reduced by the inhibition of FXI(a) or PKa. Furthermore, data from human studies suggest that these enzymes may be valuable targets to reduce thrombosis risk. In this review, we discuss the structure and function of FXI(a) and PK(a), their involvement in the development of venous and arterial thrombosis in animal models and human studies, and current therapeutic strategies.
Kommentar: Pflege in Zeiten von Corona
Authors: Heeser Alexandra-Corinna
Published: May 2020

Die WHO hat 2020 zum „Internationelen Jahr der Pflegenden und Hebammen“ ausgerufen. Anlass war der 200. Geburtstag der Pflegepionierin Florence Nightingale. Das Profil der Pflege sollte damit geschärft werden.
Ermächtigung nur für hauptberufliche Krankenhausärzte
Authors: Haser Isabel
Published: May 2020

Die Möglichkeiten für Krankenhausärzte, im ambulanten Bereich tätig zu werden, nehmen stetig zu. Dennoch gibt es Grenzen. Das Bundessozialgericht (BSG) bleibt in einer aktuellen Entscheidung dabei, dass ein Arzt, der eine (oder eine Verlängerung einer) Ermächtigung beantragt, hauptberuflich im Krankenhaus beschäftigt sein muss. Eine Vollzeitbeschäftigung ist aber nicht erforderlich.
Robotik in der Pflege: Pepper und Co entlasten Pflegekräfte
Authors: Heeser Alexandra
Published: May 2020

Die Digitalisierung und der Einsatz von assistiven Technologien eröffnet sowohl Pflegefachkräften als auch Angehörigen bei der Pflege Zuhause viele Möglichkeiten. Es erleichtert die Betreuung von Patienten, macht sie planbarer und weniger anfällig für Fehler. Alles, damit die Pflegekräfte wieder mehr Zeit für das Zwischenmenschliche haben.
Pflegebotschafterin: Visionärin mit hohen Zielen
Authors: Heeser Alexandra
Published: May 2020

Die schwäbische Gesundheits- und Krankenschwester sowie Stroke Nurse des RKU – Universitäts- und Rehabilitationskliniken Ulm GgmbH – Helena Dyck wurde im März 2019 von der Jury des Deutschen Pflegetages zur Botschafterin der Pflege geehrt. kma hat mit der 23-jährigen Krankenschwester über ihr Engagement als Pflegebotschafterin und ihre Zukunft gesprochen.
Interim-Management: Klar in Führung
Authors: Lang Michael
Published: May 2020

Wenn in Unternehmen der Healthcare Branche Veränderungsprozesse anstehen, Krisen bewältigt oder Vakanzen überbrückt werden müssen, leisten Interim Manager tatkräftige Unterstützung. Brigitte Nießen spricht im Interview darüber, wie Unternehmen von den „Managern auf Zeit“ profitieren können..
Medizintechnik: Im Dialog mit Krankenhäusern und Herstellern
Authors: Lang Michael
Published: May 2020

Medizintechnikhersteller nehmen im Krankenhaus inzwischen auch die Rolle des Beraters ein. Wie gehen Medizintechnikberater mit dieser Entwicklung um und welche Strategien empfehlen sie den Häusern angesichts knapper Kassen? Ein Gespräch mit Martin Schröter.
A first-principles study of damage induced by gaseous species He, Kr, and Xe on the structure of nuclear fuel, U3Si
Authors: Gao Haigen , Lin Tongzheng , Liu Yande , Liu Xiaolong , Luo Muxu
Published: May 2020

A first-principles approach is employed to study the damage caused by gaseous species, He, Kr, and Xe atoms, on the structures of nuclear fuel U3Si. Formation energies suggest that a U vacancy is more readily generated than is an Si vacancy, and that gaseous atoms, He, Kr, and Xe, favor residing in vacancies compared with interstitial sites. By combining the trapping energies and formation energies of secondary vacancy defects, it can be determined that the number capacity of one U or Si vacancy to trap He atoms in U3Si is two or three, while it is only one with respect to Kr and Xe. When the number of trapped He (Kr and Xe) atoms is increased to four (two), the production of a secondary U vacancy is energetically favorable, and the formation of He (Kr and Xe) bubbles can be initiated. Additionally, when an Xe atom is trapped in an Si vacancy of β-U3Si, Xe bubble evolution is predominantly controlled by diffusion. From this work, one may gain new insight into the mechanism behind bubble formation in uranium silicide fuels.
High temperature dielectric investigation, optical and conduction properties of GdFe0.5Cr0.5O3 perovskite
Authors: Boudad L. , Taibi M. , Belayachi W. , Sajieddine M. , Abd-Lefdil M.
Published: May 2020

The present study reports the synthesis of GdFe0.5Cr0.5O3 by a conventional solid-state reaction route and the investigation of its structural, morphological, and optical properties. Dielectric and electric behaviors as a function of both high temperature and frequency are also presented. GdFe0.5Cr0.5O3 crystallizes in a Pbnm orthorhombic cell with an average grain size of 670 nm. The Mössbauer spectrum at room temperature shows the existence of Fe3+ in an octahedral symmetry with the presence of short-range order between the antiferromagnetic and the paramagnetic states. An optical study reveals a direct bandgap with an energy of about Eg=1.87eV. The dielectric relaxation is explained based on the Maxwell–Wagner polarization mechanism asserted to be arising in the interfaces of grains and grain boundaries. The charge carrier hopping is assumed to be along the (Fe,Cr)3+–VO∙–(Fe,Cr)2+ chain. A high temperature dielectric study is performed between 298 and 800 K, revealing successive transitions presumed to be associated with magnetic and electric ordering. The conduction mechanism is provided by the correlated barrier hopping model, while the ac-conductivity, at high temperatures, is dominated by oxygen vacancy motion.
Cooperative strategy of SMES device and modified control for cost-effective fault ride-through enhancement and power smoothing of 10 MW class superconducting wind turbine
Authors: Huang Chunjun , Zheng Zixuan , Xiao Xianyong , Chen Xiaoyuan
Published: May 2020

Superconducting wind turbine generators (SWTGs) are an effective option of 10 MW class WTG units integrated into offshore wind farms, owing to their potential advantage of reduced size and weight compared with conventional generators. Reliable grid-connection of SWTGs faces two main challenges including fault ride through (FRT) and wind power smoothing. Traditional solutions consist mainly of device-based and control-based schemes. However, the device-based scheme causes a high-cost burden due to the introduction of additional devices, while the control-based scheme is not suitable for FRT enhancement under serious grid faults. To solve these problems, this paper presents a cooperative strategy integrated with one cost-effective superconducting magnetic energy storage (SMES) device and two modified WTG controls. The utilization of SMES devices can achieve a favorable wind power smoothing effect during normal operations and overvoltage suppressing effect in dc-link of WTG during grid faults. Moreover, two modified WTG controls of power decreasing control method and reactive power control provide effective assistance for suppressing dc overvoltage, offering adequate reactive current support and reducing the capital cost of SMES devices simultaneously. Several test cases are conducted to demonstrate the feasibility of the proposed strategy.
AC/DC hybrid electric field measurement method based on Pockels effect and electric field modulation
Authors: Yang Qing , Liu Renyuan , He Yanxiao , Luo Mandan
Published: May 2020

The electromagnetic environment under transmission lines is a concern for high-voltage transmission. For transmission corridors in which alternating-current (AC) and direct-current (DC) transmission lines are on the same tower, the electromagnetic environment at ground level is complex because of the AC/DC hybrid electric field. Generally, different instruments are used for measuring AC and DC electric fields, making it difficult to measure such fields simultaneously. Thus, we propose a method for AC/DC hybrid electric field measurement based on the Pockels effect and electric field modulation. The principle of the measurement is discussed in detail. An experimental platform is set up to verify the feasibility and effectiveness of the proposed method and to calibrate the sensor. It shows that the sensor realizes simultaneous measurement of AC and DC electric field intensities as well as judgment of the polarity of the DC electric field. The measurable range is 1.05–150 kV/m (peak-to-peak value) for the AC electric field and 1.23–150 kV/m for the DC electric field with a maximum measurement error of less than 5%. The sensor has good repeatability, linearity, and low hysteresis, which can be used in power grids for AC/DC hybrid electric field measurements.