bluuebunny/crossref_metadata_2025 huggingface dataset:
The task of determining the matching of actual and planned operation plans in a dispatch control system of the road transport
Authors: Fadeev A I
Published: November 2019

The article deals with the task of determining the matching between actual and planned operation plans in a dispatch control system of the road transport. The actual route of movement along the transport network is recorded as navigation data in the form of an ordered point set which had been passed through: control points identifiers and time stamps for both arrival and departure times. A new approach is proposed to determining the matching between planned and actual movement routes, which is considered as required for the dispatch control system of the road transport. Determining the matching between actual and planned movement routes is proposed to consider as the task of finding the longest common subsequence of two ordered sets: points of the planned and actual movement routes. In this way, the problem under consideration is scaled down to the classical dynamic programming problem — finding the longest common subsequence of several rows. Based on that the article presents a developed algorithm for solving the problem of finding the longest common subsequence of planned and actual movement route points.
Theoretical justification of the over-the-road monitoring method of the shock absorbers technical state under operation conditions
Authors: Lysenko A V , Fedotov A I , Tikhov-Tinnikov D A
Published: November 2019

The article describes the mathematical apparatus classifying the movement of the sprung and unsprung vehicle masses in space, as well as the processes of interaction of its elastic tires with the road support surface when driving under the influence of lateral force. The results of calculations of the mathematical model allow one to scientifically justify the test modes and diagnostic parameters of the over-the-road method of monitoring the technical condition of shock absorbers. The normalized values of the found diagnostic parameters are proposed as criteria for assessing the vehicle stability when moving under the influence of lateral force and varying the technical condition of the shock absorbers.
Application of the Hakimi method for solving the problem of placement of optimal crews of emergency commissioners
Authors: Lukoyanov V , Vorobyev A , Rassoha V
Published: November 2019

The urgency of the problem being investigated is due to the constant presence of traffic jams on the major cities streets caused by various traffic incidents, which dramatically reduce the traffic capacity of the roadway and impede an unhindered passage for road users. One of the ways to solve this problem is the institute of emergency commissioners, which currently does not fully perform the functions imposed on it. In particular, the late arrival at the crash site contributes to the appearance of traffic jam. The paper proposes a scientifically based approach to solving the problem of rational crew’s deployment of emergency commissioners in the urban area. The article materials may be useful for regulation of the services of emergency commissioners, the State Traffic Safety Inspectorate, and for coordinating their cooperation with insurance companies.
Increasing the shape accuracy of the hardened parts of the frame by technological methods
Authors: Makaruk A A , Pashkov A A , Samoylenko O V
Published: November 2019

Aluminum alloy parts of the aircraft’s power frame are usually ribbed longitudinally and transversely to increase rigidity. As a result, the cross-section of such parts is a complex complex shape in the form of a brand, channel, I-beam, etc. with straight and inclined shelves. In the manufacturing of parts in the process of both mechanical processing and subsequent impact hardening there is an undesirable deformation (leashes), which is expressed in the deviation from the plane and saber-like form. After milling, the leashes can be removed by local plastic deformation methods, such as rolling by rollers, or by pressing, and after hardening, mechanical treatment, including straightening by local plastic deformation methods, is not allowed by the industry standard technical procedure. Expansion of technological possibilities of manufacturing of low-rigid parts with application of technology of preventive deformation -introduction of pre-distortion of the form of a detail for compensation of the leashes arising on the subsequent strengthening operations by methods of surface plastic deformation.
Analysis of applicability of polymer, composite materials as components of aeronautical structures
Authors: Moskvitin V N , Makarov V I , Leonovich D S
Published: November 2019

The paper considers the problems of using composite materials to create power units of modern passenger planes. It gives examples of crash situations involving planes of the leading companies, describes some technological aspects in the production of composite parts.
Grinding of aluminum alloy panels after shot peen forming on contact type installations
Authors: Starodubtseva D A , Koltsov V P , Vinh L T
Published: November 2019

Absract

One of the key technological processes of production of the airframe of an aircraft is the manufacture of large-sized contour forming details such as “panel” and “fuselage shell”. To date, the most promising method of obtaining the required aerodynamic shape of such parts is the method of shot peen forming. It consists of processing the outer surface of a part with a stream of fast-moving shots, because of which a specific profile of micro roughness stays on the surface, characterized by numerous prints of fraction of different diameter and depth [1-5]. The grinding of the flap wheel is part of the forming process and improve the quality of the original surface. For the formation of large-sized surfaces, the scientists of INRTU have developed and introduced in the conditions of the Irkutsk aviation plant a unique installation for the shot peen forming– grinding of UDF-4 with CNC system [6, 7]. The primary, and the main difference of domestic development from foreign counterparts, is the division of the forming operation into smaller stages for easier process control. The development and improvement of grinding technology requires the development of appropriate methods and special software for it, which enables to automate the processing process.
Studying the effect of surface conditioning on the corrosion performance of titanium dental implants
Authors: Masia N D E , Smit M , Mwamba A I , Moema J S
Published: November 2019

The biocompatibility of dental implants is dependent on good interaction between implant-human body tissue and a good osseointegration. The surface roughness plays an important role enhancing bone healing and promoting biomechanical properties at the bone/implant interface. The increase in surface roughness can simultaneously improve cell migration and attachment of an implant, and enhance the osseointegration process. However surface roughness has shown to be detrimental to corrosion, raising the need to achieve a balance between good osseointegration and corrosion performance. This study characterised the corrosion performance of commercially pure titanium grade 4 with different surface conditionings. Implants in the form of 15 mm discs and implant screws were tested in basic Ringers lactate solution of pH 5.5 at 37°C and in modified Ringers of pH 2. Corrosion tests included open circuit potential (OCP), potentiodynamic polarization test (PDP) and mass loss corrosion tests. Metallurgical characterisation showed that titanium Grade 4 consisted of equiaxed alpha (α-Ti) grains. The OCP test showed that the machined implants were nobler than the roughened implants. The corrosion rates obtained were very low, below 0.13 mm/y which is an acceptable corrosion rate for biomaterial design and application. Mass-loss tests showed that the alloys passivated regardless of the surface conditioning. The machined surface had a corrosion resistance higher than that of the roughened surface finish in all conditions.
Development of a mathematical equation describing the strain hardening behaviour of metastable AISI 301 austenitic stainless steel
Authors: Mukarati T W , Mostert R J , Siyasiya C W
Published: November 2019

The strain hardening behaviour of AISI 301 metastable austenite steel was analysed by evaluating tensile data against the empirical mathematical equations of Hollomon, Ludwik and Ludwigson. It was found that these equations were inadequate to model this TRIP steel with low stacking fault energy (SFE). It was found that the fraction of strain-induced martensite could be expressed as a sigmoidal function of the applied strain. The log-log plots of true stress and true plastic strain from 5% to εUTS performed with uniaxial isothermal tests at 30 °C were thereafter adequately fitted with a sigmoidal curve. The instantaneous strain hardening exponent was determined as the slope of the above-mentioned sigmoidal curve at a specific strain value. The strain hardening exponent and the rate of strain hardening dσ/dε) increases with deformation due to formation of strain-induced martensite to a maximum and thereafter decreases as the volume fraction of strain-induced martensite approximates saturation. The variation of the instantaneous strain hardening exponent as a function of plastic strain and the strength coefficient, K, at 30 °C was deduced. A high value of K, 1526MPa, was determined. A correlation between the extent of martensitic transformation and the value of the instantaneous strain hardening exponent was observed. This work is part of the project that seeks to develop a constitutive model describing the flow stress during plastic deformation as a function of both plastic strain and the resulting martensitic transformation at different temperatures and strain rates and which accounts for the isotropic hardening process.
SiC and Al surface cladding of Ti-6Al-4V for improved wear properties – The binary advantage
Authors: Okoli U O , Otunniyi I O , Adebiyi I D
Published: November 2019

Ti-6Al-4V enjoys high specific strength, toughness and excellent corrosion resistance, but suffers high friction coefficient, severe adhesive wear and sensitivity to fretting wear. Laser surface cladding is one of the surface modification techniques used for improving on these demerits. Using a 4.4Kw continuous wave Nd-YAG laser processor, the surface cladding of as received Ti-6Al-4V alloy was done with mixtures of SiC and Al powders in different ratios. The SiC powder can serve as reinforcing particles and helps improve surface wear properties in resulting surface metal matrix composite while aluminium improves on the wetting between the metal and the reinforcement SiC phase. The success of this, however, depends on the careful optimisation of the powder ratio, which dictates the resulting phases and microstructural evolutions. Study of the cladding with scanning electron microscope (energy dispersive spectroscopy), optical microscope and x-ray diffraction revealed formation of intermetallic phases such as AlSiTi2, Ti7Al5Si12, TiSi2, AlSi3Ti2, Al6Ti19, Ti2VAl, AlTi3, AlCTi2, Ti3SiC2and Ti5Si4, which should enhance micro-hardness and tribological properties of the surface relative to the bulk as-received alloy. 90:10 weight percentage ratio of SiC and Al powder mixture gave the best microhardness with a value of 1169.95 Hv, compared to 323.67 Hv of the as-received, and mass loss under abrasive wear tests was only 40% of the as received. The morphology obtained for the abraded surfaces is also indicative of this improvement. In carefully optimised proportions and laser condition, the binary combination of Al and SiC powders suffice for well improved Ti-6Al-4V surface properties.
Morphological characterization of recycled powder and microstructures of Ti-6Al-4V components synthesized by LENS additive manufacturing
Authors: Sibisi P N , Popoola A P I , Arthur N K K , Pityana S L , Popoola O M
Published: November 2019

Direct Metal Laser Deposition (DMLD) processes such as LENS are gaining ground in commercial manufacturing processes of functional end-products. This is attributed to this process being popularized as a sustainable technology with the potential to substitute the energy intensive, wasteful and environmentally unfriendly traditional techniques. However, during processing a significant fraction of the injected powders do not end up as part of the final component. The properties of these powders change due to heating resulting in coalescence and possible chemical reactions with the surrounding environment. A potential way to overcome this is by adopting an effective powder recycling procedure by which material use efficiency can be improved. Even so, these changes may have detrimental impact on the mechanical properties of the end-product. The objective of this paper is to investigate the effect of powder recycling on mechanical properties as a consequence of a change in powder characteristics. The potential for improving the LENS process by powder recycling process has been evaluated by comparatively studying the feedstock characteristics, i.e. morphology, particle size distribution and microstructure of powders in as received state and after laser exposure during repeated deposition cycles. Microstructures, micro-hardness and Density of the built samples were measured after the first deposition-normalization-reuse cycle. The results revealed a correlation between the powder characteristics and the properties of the corresponding built sample used for that specific deposition.
Tensile properties and microstructural characterization of additive manufactured, investment cast and wrought Ti6Al4V alloy
Authors: Beyl K , Mutombo K , Kloppers C P
Published: November 2019

This paper presents an evaluation of the tensile properties and microstructural characterization of Ti6Al4V alloy manufactured with three different processing routes; traditional wrought processing, investment cast and Laser Engineered Net Shaping (LENS). Tensile specimens were machined from each process and tensile tested at room temperature. Fractured specimens were characterized using light optical microscopy, stereo microscopy, microhardness and Scanning Electron Microscopy (SEM) to investigate the microstructural morphology and the structural hardness variation. The investment cast Ti6Al4V alloy microstructure revealed large equiaxed grains containing various orientated lamellar colonies. The additive manufactured microstructure revealed long columnar grains with Widmanstatten α’ martensite laths and retained β grain boundaries. While the wrought Ti6Al4V microstructure was observed as smaller equiaxed grains with large colonies of fine lamellar and transformed β. Additive manufactured specimens had higher yield strength, ultimate tensile strength and hardness compared to the investment cast and wrought manufactured specimens.
Preparation and microstructural characterization of the 60Al-40V master alloy
Authors: Mapoli T O , Annan K A , Siyasiya C W , Mutombo Kalenda
Published: November 2019

The present study focused on preparation and characterization of 60Al-40V master alloy which was produced via aluminothermic process. The study assessed the production in order to provide the optimum Al requirement for maximum recovery of the V. V2O5(Vanadium pentoxide) and Al metal were mixed in the proportion of producing 60Al-40V and Al2O3(slag) through an exothermic reaction. Microstructural analysis and phase identification were done using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) equipped with Energy Dispersive Spectroscopy (EDX) and X-Ray Diffraction (XRD) analyses. The XRD revealed diffraction peaks mainly of the Al3V phase and some peaks of slightly homogenized Al8V5intermetallic compounds. The chemical composition was found to be 65 ± 0.03 and 35 ± 0.03 wt. % Al and V respectively. Good agreement between the experimental results and the predicted phases using Thermo-Calc. Software was observed.
Development and characterization of porous Ti-Sn-SiC composite intended for biomedical application
Authors: Mathebula C R , Matizambuka W , Bolokang A S
Published: November 2019

Titanium-based materials have received great research interest this is mainly due to their promising specific strength, thermal stability, corrosion resistance, and biocompatibility. Porous titanium has been shown to exhibit desirable properties as biomedical materials. Ti-Sn-SiC composites of different compositions were synthesized through mixing Ti, Sn and SiC powders. The study was carried out by blending and cold-pressing followed by sintering at a 1400°C. Microstructures of the materials were studied using an optical microscope (OP) and scanning electron microscopy (SEM). To investigate structural development and phase transformation, x-ray diffraction (XRD) was performed. A porous Ti-Sn-SiC composite was achieved which is favorable for biomedical application.
Preparation and characterization of glass-ceramic composites from South African coal fly ash
Authors: Modiga A , Sosibo N , Singh N
Published: November 2019

Though fly ash in South Africa has mainly been utilized in the construction industry, a large portion of it is still discarded. Production of glass-ceramic composites through fly ash devitrification has gradually become one of the applications being examined internationally. This study reports the investigation of producing glass-ceramic composites from fly ash and varying quantities of beverage waste glass and magnesium oxide as main raw materials. Glasses were obtained by melting fly ash and its additives using an arc furnace. Based on their behaviour when subjected to differential thermal analysis, the glasses were then crystallised through a double-staged thermal treatment to form glass-ceramic composites. The composition and behaviour of the glass-ceramic composites were investigated using X-ray diffraction, Scanning Electron Microscopy, mechanical and chemical assessments. The crystal content in the glass-ceramic composites increased as the magnesium oxide content was increased. The desired diopside phase decreased with an increased magnesium oxide content and ultimately resulted in the formation of forsterite and anorthite as the major and second major phases respectively. The glass-ceramic composites with lesser amounts of magnesium oxide were chemically and thermally resistant and they also demonstrated high cold compressive strength.
Development of MgAl2O4grain refiner in Al in-situ composite through H3BO3addition
Authors: Chandramohan P , Olubambi P A , Raghu R , Obadele B A
Published: November 2019

In the present work, a novel approach has been made for synthesis of in-situ Magnesium Aluminate (MgAl2O4) particles in the Al-4Mg alloy by Boric Acid (H3BO3) precursor addition (1 wt %, 1.5 wt % and 2 wt %) during the casting process. The developed composite has been investigated for its microstructural characteristics and corrosion performance. Scanning Electron Microscopy and Energy Dispersive Spectroscopy examination revealed the formation of MgAl2O4 particles in the composite. Potentiodynamic polarization corrosion experiments were performed on the Al-4Mg/H3BO3 composite specimens (1 wt %, 1.5 wt % and 2 wt %) in three different medium (3.5 % Sodium Chloride-NaCl, 1 M Sulphuric Acid-H2SO4 and 1 M Hydrochloric Acid-HCl). Corrosion results showed that Al-4Mg/1.5 wt % H3BO3 composite specimen exhibited better corrosion resistance in 3.5 % NaCl, 1 M H2SO4 and 1 M HCl medium due to the significant grain refinement produced by MgAl2O4 particles. The developed composite with better corrosion properties can be utilized for marine and naval application.
First-principles studies on the structural, electronic and mechanical properties of L1o and L12 FexPt1-x alloys
Authors: Lethole N L , Chauke H R , Ngoepe P E
Published: November 2019

Bimetallic FexPt1-x alloys with the L10 and L12 structures have recently gained a lot of consideration in practical applications for solid-state devices, storage of ultra-high density magnetic data and biomedicine. This is due to their high magnetic and magnetocrystalline anisotropy, density, and coercivity. In order to gain knowledge on the structural, electronic and mechanical properties of the cubic and tetragonal FexPt1-x alloys, we have calculated their equilibrium lattice constants, density of states, and elastic constants at 0 K, employing first-principles calculations. The calculated equilibrium lattice constants were found to be in good agreement with the experimental data to within 3 %. All independent elastic constants satisfy the necessary stability conditions for both cubic and tetragonal systems, suggesting mechanical stability. The shear anisotropic factors predict that the tetragonal FexPt1-x crystals are highly anisotropic along the {001} plane than {100}. Moreover, the percentage of bulk (AB) and shear (AG) anisotropies revealed completely isotropic systems in the bulk and slightly anisotropic in shear modulus.
Surface morphology characterisation for parts produced by the high speed selective laser melting
Authors: Shange M , Yadroitsava I , Pityana S , Yadroitsev I , Bester D
Published: November 2019

Additive Manufacturing (AM) systems are unique in terms of fast production and lead time to market. South Africa has built the AM Laser Powder Bed Fusion (LPBF) machine called Aeroswift with the world’s largest build volume and highest speed. Surface roughness of LPBF parts depends on process-parameters. High surface roughness and deformations during processing limit the application of this technology for certain industrial applications that require high precision. This study characterises the surface roughness for self-supported parallelepipeds samples produced using the Aeroswift platform. Test artefact parallelepipeds were built with 0-90 degrees sloping angles with respect to the building direction. Surface roughness for the as-built samples was analysed using Mitutoyo SURFTEST SJ-210 system and Zeiss Smartzoom 5 digital microscope. It was found that roughness values were higher for the bottom surfaces (overhang part) compared to upward surfaces, as expected. This was attributed to the higher amount of attached partially melted powder particles that were observed on the downward surface. Absolute values of Ra and Rz versus scanning direction and slope angle were found and analysed.
Study on the microstructure of 2124 aluminum alloy subjected to stress assisted aging
Authors: Quan L W , Wang C C
Published: November 2019

The effect of a load on the microstructure of 2124 aluminum alloy was investigated by employing transmission electron microscopy. When the alloy was aged at 190°C under a load of 6.05 kg, the deformation was increased with the aging time prolonging. Meanwhile the length of Al2CuMg(S) phase was shorter than the length of S phase in the alloy without loading. At the same time, there was no preferential orientation effect on S phase or Genier Preston Bagaryatsky (GPB) zones.
Effect of Hypoxia on Embryo Development in Silkworm Eggs
Authors: Gong Jing , Zhang Yuhao , Yan Jiamin , Shang Shan , Gu Hanfei , Zhu Yong
Published: November 2019

Diapause is a common phenomenon during which organisms suspend development to overcome difficult environmental conditions. The silkworm is a classical model for the study of egg diapause. Our previous study showed that gene expression is similar in silkworm eggs treated with hyperoxia or HCl. In the present study, to further explore the mechanism of diapause prevention, nondiapause eggs and hyperoxia-/HCl-activated diapause eggs were treated with hypoxia. Embryo morphology, hatching time, and reactive oxygen species (ROS) levels were analyzed across different developmental stages. The results showed that hypoxia may inhibit the embryonic development of silkworm eggs. The morphology of nondiapause eggs under hypoxia differed from that of nondiapause eggs under normoxia during embryonic development, which, in turn, was similar to that of diapause eggs. Meanwhile, the hatching time of nondiapause eggs under hypoxia was delayed significantly. Moreover, the ROS levels of nondiapause eggs changed under hypoxia, showing a pattern similar to that of diapause eggs. Interestingly, when activated diapause eggs were treated with hypoxia, some eggs hatched in the following spring. These results suggest that early embryogenesis is largely dependent on oxygen levels and that hypoxia may induce a diapause-like state in activated diapause eggs. Additionally, ROS levels may play a key role in diapause. Thus, this study provides valuable information on the mechanisms of diapause and diapause prevention in silkworms.
Determination of Bisphenol A by High-Performance Liquid Chromatography Based on Graphene Magnetic Dispersion Solid Phase Extraction
Authors: Li Xinghua , Li Shuang , Bai Jialei , Peng Yuan , Ning Baoan , Shi Hongmei , Kang Weijun , Zhou Huanying , Gao Zhixian
Published: November 2019

Bisphenol A (BPA), as one of the environmental endocrine disruptors, is extensively existing and threatening to human health. To evaluate the environmental exposure level and protect human from the hazard of BPA, a precise and sensitive method is established. In this work, Graphene@ Fe3O4 (G@Fe3O4) is prepared by chemical coprecipitation method as magnetic dispersion solid phase extraction (MDSPE) material. The rapid and specific detection method of BPA is carried out by high-performance liquid chromatography (HPLC). Properties of G@Fe3O4 are identified by the fourier infrared spectrum and scanning electron microscopy. Conditions of solid phase extraction are optimized. Under the optimal extraction conditions, G@Fe3O4 has perfect enrichment effect on BPA. There is a good linear relationship in the range of 5.0~1000.0 μg/L with the correlation coefficient of 0.9997. The detection limit is 0.1 μg/L. This method is applied to water samples successfully, and recoveries of BPA are between 88.19% and 99.56% (RSDs < 3.00%). G@Fe3O4 was synthesized, which was used to extract BPA in water samples before HPLC analysis, and has shown perfect extraction ability toward BPA, which indicates that the determination method of BPA by HPLC based on graphene MDSPE is faster and more precise.
Gentamicin Alone Is Inadequate to Eradicate Neisseria Gonorrhoeae From the Pharynx
Authors: Barbee Lindley A , Soge Olusegun O , Morgan Jennifer , Leclair Angela , Bass Tamara , Werth Brian J , Hughes James P , Golden Matthew R
Published: November 2019

Background

Centers for Disease Control and Prevention (CDC) guidelines recommend 240 mg gentamicin plus 2 g azithromycin for the treatment of gonorrhea in cephalosporin-allergic patients. The efficacy of gentamicin alone in the treatment of pharyngeal gonorrhea is uncertain.

Methods

Between September 2018 and March 2019, we enrolled men who have sex with men with nucleic acid amplification test–diagnosed pharyngeal gonorrhea in a single-arm, unblinded clinical trial. Men received a single 360-mg intramuscular dose of gentamicin and underwent test of cure by culture 4–7 days later. The study measured creatinine at enrollment and test of cure, serum gentamicin concentration postdose to establish peak concentration (Cmax), and standard antimicrobial minimum inhibitory concentrations (MICs) by agar dilution. The trial was designed to establish a point estimate for gentamicin’s efficacy for pharyngeal gonorrhea. We planned to enroll 50 evaluable participants; assuming gentamicin was 80% efficacious, the trial would establish a 95% confidence interval (CI) of 66%–90%. We planned interim analyses at n = 10 and n = 25.

Results

The study was stopped early due to poor efficacy. Of 13 enrolled men, 10 were evaluable, and only 2 (20% [95% CI, 2.5%–55.6%]) were cured. Efficacy was not associated with gentamicin Cmax or MIC. No participants experienced renal insufficiency. The mean creatinine percentage change was +5.2% (range, −6.7% to 21.3%). Six (46%) participants experienced headache, all deemed unrelated to treatment.

Conclusions

Gentamicin alone failed to eradicate Neisseria gonorrhoeae from the pharynx. Clinicians should use caution when treating gonorrhea with the CDC’s current alternative regimen (gentamicin 240 mg plus azithromycin 2 g) given increases in azithromycin resistance and gentamicin’s poor efficacy at the pharynx.

Clinical Trials Registration

NCT03632109.
Abnormal neurovascular coupling as a cause of excess cerebral vasodilation in familial migraine
Authors: Staehr Christian , Rajanathan Rajkumar , Postnov Dmitry D , Hangaard Lise , Bouzinova Elena V , Lykke-Hartmann Karin , Bach Flemming W , Sandow Shaun L , Aalkjaer Christian , Matchkov Vladimir V
Published: November 2019

Aims

Acute migraine attack in familial hemiplegic migraine type 2 (FHM2) patients is characterized by sequential hypo- and hyperperfusion. FHM2 is associated with mutations in the Na, K-ATPase α2 isoform. Heterozygous mice bearing one of these mutations (α2+/G301R mice) were shown to have elevated cerebrovascular tone and, thus, hypoperfusion that might lead to elevated concentrations of local metabolites. We hypothesize that these α2+/G301R mice also have increased cerebrovascular hyperaemic responses to these local metabolites leading to hyperperfusion in the affected part of the brain.

Methods and results

Neurovascular coupling was compared in α2+/G301R and matching wild-type (WT) mice using Laser Speckle Contrast Imaging. In brain slices, parenchymal arteriole diameter and intracellular calcium changes in neuronal tissue, astrocytic endfeet, and smooth muscle cells in response to neuronal excitation were assessed. Wall tension and smooth muscle membrane potential were measured in isolated middle cerebral arteries. Quantitative polymerase chain reaction, western blot, and immunohistochemistry were used to assess the molecular background underlying the functional changes. Whisker stimulation induced larger increase in blood perfusion, i.e. hyperaemic response, of the somatosensory cortex of α2+/G301R than WT mice. Neuronal excitation was associated with larger parenchymal arteriole dilation in brain slices from α2+/G301R than WT mice. These hyperaemic responses in vivo and ex vivo were inhibited by BaCl2, suggesting involvement of inward-rectifying K+ channels (Kir). Relaxation to elevated bath K+ was larger in arteries from α2+/G301R compared to WT mice. This difference was endothelium-dependent. Endothelial Kir2.1 channel expression was higher in arteries from α2+/G301R mice. No sex difference in functional responses and Kir2.1 expression was found.

Conclusion

This study suggests that an abnormally high cerebrovascular hyperaemic response in α2+/G301R mice is a result of increased endothelial Kir2.1 channel expression. This may be initiated by vasospasm-induced accumulation of local metabolites and underlie the hyperperfusion seen in FHM2 patients during migraine attack.
Impact of simplified therapeutic guidelines on antibiotic prescriptions: a prospective multicentre comparative study
Authors: Roger Pierre-Marie , Peyraud Ingrid , Vitris Michel , Romain Valérie , Bestman Laura , Blondel Lionel , Gras Hélène , Hauchart Christine , Morandi Véronique , Rancezot Agnès , Borredon Gaelle , Dautezac Véronique
Published: November 2019

Objectives

We studied the impact of simplified therapeutic guidelines (STGs) associated with accompanied self-antibiotic reassessment (ASAR) on antibiotic use.

Methods

Prospective antibiotic audits and feedback took place at 15 hospitals for 12 months, allowing STGs with ≤15 drugs to be devised. STGs were explained to prescribers through sessions referred to as ASAR. Optimal therapy was defined by the conjunction of a diagnosis and the drug specified in the STGs. Analysis of consumption focused on critical drugs: amoxicillin/clavulanic acid, third-generation cephalosporins and fluoroquinolones.

Results

We compared prescriptions in five hospitals before (n = 179) and after (n = 168) the implementation of STGs + ASAR. These tools were associated with optimal therapies and amoxicillin/clavulanic acid prescriptions [adjusted odds ratio (AOR) 3.28, 95% CI 1.82–5.92 and 2.18, 95% CI 1.38–3.44, respectively] and fewer prescriptions for urine colonization [AOR 0.20 (95% CI 0.06–0.61)]. Comparison of prescriptions (n = 1221) from 10 departments of three clinics with STGs + ASAR for the first quarters of 2018 and 2019 revealed that the prescriptions by 23 ASAR participants more often complied with STGs than those by 28 other doctors (71% versus 60%, P = 0.003). STGs alone were adopted by 10 clinics; comparing the prescriptions (n = 311) with the 5 clinics with both tools, we observed fewer unnecessary therapies in the latter [AOR 0.52 (95% CI 0.34–0.80)]. The variation in critical antibiotic consumption between 2017 and 2018 was −16% for the 5 clinics with both tools and +20% for the other 10 (P = 0.020).

Conclusions

STGs + ASAR promote optimal antibiotic therapy and reduce antibiotic use.
Can miRNAs Serve as Potential Markers in Thermal Burn Injury: An In Silico Approach
Authors: Shukla Sandeep K , Sharma Ajay K , Bharti Rhythm , Kulshrestha Vidit , Kalonia Aman , Shaw Priyanka
Published: November 2019

Burn injury has been a major cause of morbidity at global levels. They can occur by multiple agents, such as thermal radiation and chemicals. Among all, thermal burn is predominant and may require specialized treatment in some patients. Although various biomarkers are reportedly used in thermal burn for understanding the pathophysiology of the injury, their limitations prompt for the search of suitable markers that can address the depth and severity of the burn. MicroRNAs (miRNAs) are conserved noncoding molecules that seem to be the promising marker due to their role in multiple pathways and participation in different physiological processes of the body. The present review highlights the role of miRNAs in the repair of the wound and their interaction with specific genes in response to burn stress. Key miR candidates include miR-21, miR-29a, miR-378a-5p, miR-100, miR-27b, miR-200c, miR-150, miR-499-5p, miR-92a, miR-194, and miR-146b, which are identified for their respective targets involved in wound repair. Furthermore, bioinformatics and computational tools were used to confirm the miRNAs and their specific targets. Gene and miRNA expression data sets were downloaded from Research Collaboratory for Structural Bioinformatics Protein Data Bank Database and RNAComposer, respectively, and docked by PatchDock. The possible implications of the identified miRNAs could be in understanding the mechanism of burn injury. These can also be studied with the available drugs being used for burn injury. Apart from that, new intended molecules may also be tested for their effect on these miRNAs.
Comparative Study of Promastigote- and Amastigote-Initiated Infection of Leishmania infantum (Kinetoplastida: Trypanosomatidae) in Phlebotomus perniciosus (Diptera: Psychodidae) Conducted in Different Biosafety Level Laboratories
Authors: Vaselek Slavica , Prudhomme Jorian , Myskova Jitka , Lestinova Tereza , Spitzova Tatiana , Bañuls Anne-Laure , Volf Petr
Published: November 2019

Sand flies (Diptera: Psychodidae) are natural vectors of Leishmania. For the initiation of sand fly experimental infections either Leishmania amastigotes or promastigotes can be used. In order to obtain comparable results, it is necessary to adjust and standardize procedures. During this study, we conducted promastigote- and amastigote-initiated infections of Leishmania infantum Nicolle, 1908 parasites in Phlebotomus (Larroussius) perniciosus Newstead, 1911 in two laboratories with different levels of biosafety protection. Protocol originally designed for a biosafety level 2 facility was modified for biosafety level 3 facility and infection parameters were compared. Particularly, specially designed plastic containers were used for blood feeding; feeders were placed outside the sand fly cage, on the top of the mesh; feeding was performed inside the climatic chamber; separation of engorged females was done in Petri dishes kept on ice; engorged females were kept in the cardboard containers until dissection. All experiments, conducted in both laboratories, resulted in fully developed late stage infections with high number of parasites and colonization of the stomodeal valve. We demonstrated that protocol originally designed for biosafety level 2 facilities can be successfully modified for other biosafety facilities, depending on the special requirements of the individual institution/laboratory.
Spring temperatures affect senescence and N uptake in autumn and N storage for winter in Rhynchospora alba (Cyperaceae)
Authors: Byne Kyelle , Ryser Peter
Published: November 2019

Environmental and physiological factors underlying variation in timing of autumn senescence are not well known. We investigated how the time of the onset of the growth in spring affects senescence and its functional consequences for nitrogen (N) uptake in autumn and storage of N for the winter, in a species that each year develops its bulbils for storage and overwintering anew. Rhynchospora alba was grown outdoors with two treatments, identical except for a 3 week difference in the start of growth in May. Leaf and root growth and senescence, and N uptake were recorded from August to November. By August, late-starting plants had caught up in size and total N content, but had smaller bulbils. They had a higher δ 13C, indicating a higher stomatal conductance during growth. Leaf and root senescence were delayed, extending 15N tracer uptake by 4 weeks. Nevertheless, after senescence, plants with an early start had 55% more N in their overwintering bulbils, due to earlier and more efficient remobilization. We conclude that timing of senescence in R. alba is a result of an interplay between the status of winter storage and cold temperatures, constrained by a trade-off between prolonged nutrient uptake and efficient remobilization of nutrients.
Targeted insertional mutagenesis libraries for deep domain insertion profiling
Authors: Coyote-Maestas Willow , Nedrud David , Okorafor Steffan , He Yungui , Schmidt Daniel
Published: November 2019

Domain recombination is a key principle in protein evolution and protein engineering, but inserting a donor domain into every position of a target protein is not easily experimentally accessible. Most contemporary domain insertion profiling approaches rely on DNA transposons, which are constrained by sequence bias. Here, we establish Saturated Programmable Insertion Engineering (SPINE), an unbiased, comprehensive, and targeted domain insertion library generation technique using oligo library synthesis and multi-step Golden Gate cloning. Through benchmarking to MuA transposon-mediated library generation on four ion channel genes, we demonstrate that SPINE-generated libraries are enriched for in-frame insertions, have drastically reduced sequence bias as well as near-complete and highly-redundant coverage. Unlike transposon-mediated domain insertion that was severely biased and sparse for some genes, SPINE generated high-quality libraries for all genes tested. Using the Inward Rectifier K+ channel Kir2.1, we validate the practical utility of SPINE by constructing and comparing domain insertion permissibility maps. SPINE is the first technology to enable saturated domain insertion profiling. SPINE could help explore the relationship between domain insertions and protein function, and how this relationship is shaped by evolutionary forces and can be engineered for biomedical applications.
Epigenetic reprogramming and chromatin accessibility in pediatric diffuse intrinsic pontine gliomas: a neural developmental disease
Authors: Mendez Flor M , Núñez Felipe J , Garcia-Fabiani Maria B , Haase Santiago , Carney Stephen , Gauss Jessica C , Becher Oren J , Lowenstein Pedro R , Castro Maria G
Published: November 2019

Diffuse intrinsic pontine glioma (DIPG) is a rare but deadly pediatric brainstem tumor. To date, there is no effective therapy for DIPG. Transcriptomic analyses have revealed DIPGs have a distinct profile from other pediatric high-grade gliomas occurring in the cerebral hemispheres. These unique genomic characteristics coupled with the younger median age group suggest that DIPG has a developmental origin. The most frequent mutation in DIPG is a lysine to methionine (K27M) mutation that occurs on H3F3A and HIST1H3B/C, genes encoding histone variants. The K27M mutation disrupts methylation by polycomb repressive complex 2 on histone H3 at lysine 27, leading to global hypomethylation. Histone 3 lysine 27 trimethylation is an important developmental regulator controlling gene expression. This review discusses the developmental and epigenetic mechanisms driving disease progression in DIPG, as well as the profound therapeutic implications of epigenetic programming.
Effect of sucralose and aspartame on glucose metabolism and gut hormones
Authors: Ahmad Samar Y , Friel James K , Mackay Dylan S
Published: November 2019

Non-nutritive sweeteners are thought to be useful replacements for caloric sweeteners in sweet food and beverages, since the reduction in energy and carbohydrate intake may lead to health benefits stemming from weight management and glycemic control. However, the potential effects of non-nutritive sweeteners on glucose metabolism and gut hormones have not been determined definitively. Here, the available evidence of the effects of aspartame and sucralose consumption on glucose metabolism and gut hormones is reviewed. A majority of studies have found that consumption of aspartame or sucralose has no effect on concentrations of blood glucose, insulin, or gut hormones; however, 2 trials have shown that aspartame consumption affects glucose, insulin, and glucagon-like peptide 1 concentrations, while only a few trials have shown that sucralose consumption affects glucose, insulin, and glucagon-like peptide 1 concentrations. One study found higher glucose concentrations after sucralose consumption, while 3 studies found lower concentrations and 33 studies found no change in glucose concentrations. Moreover, only 4 studies reported increased concentrations of glucagon-like peptide 1. Three studies reported decreased insulin sensitivity following sucralose consumption, while 1 trial reported an increase in insulin sensitivity. In summary, the evidence from the clinical trials conducted to date is contradictory because of the different protocols used.
Lipid-modifying effects of krill oil vs fish oil: a network meta-analysis
Authors: Kim Myeong Gyu , Yang Inkyou , Lee Han Sol , Lee Jae-Young , Kim Kyungim
Published: November 2019

Context

Krill oil is a good source of n-3 phospholipids and has greater bioavailability than fish oil, which contains n-3 triglycerides. However, it is unclear whether krill oil affects circulating lipid concentrations more beneficially than fish oil.

Objective

A network meta-analysis was conducted to compare the lipid-modifying effects of krill oil and fish oil.

Data Sources

PubMed and Embase databases were searched.

Study Selection

A total of 64 randomized controlled trials that determined the lipid-modifying effects of krill oil or fish oil were selected.

Data Extraction

The MetaXL program was used for meta-analysis. A subgroup analysis and a network meta-regression were conducted to investigate the dose-response effect of the n-3 fatty acid content of fish oil and krill oil.

Results

Krill oil was associated with significantly lower triglyceride levels than control supplements (weighted mean difference [WMD] −23.26 [95%CI, −38.84 to −7.69]). However, the net differences in triglycerides (WMD −4.07 [95%CI, −15.22 to 7.08]), low-density lipoprotein cholesterol (WMD 3.01 [95%CI, −5.49 to 11.51]), high-density lipoprotein cholesterol (WMD 1.37 [95%CI, −3.73 to 6.48]), and total cholesterol (WMD 1.69 [95%CI, −6.62 to 10.01]) were not significantly different between the krill oil and fish oil groups. One gram of n-3 fatty acids contained in fish oil and krill oil lowered median triglycerides by 8.971 mg/dL (95% credible interval [CrI], 2.27 to 14.04) and 9.838 mg/dL (95%CrI, 0.72 to 19.40), respectively.

Conclusions

The lipid-modifying effects of krill oil and fish oil do not differ. The reduction in triglycerides depends on the dose of n-3 fatty acids consumed.
Characterization of the Fungal Community Associated with Root, Crown, and Vascular Symptoms in an Undiagnosed Yield Decline of Winter Squash
Authors: Rivedal Hannah M. , Stone Alexandra G. , Severns Paul M. , Johnson Kenneth B.
Published: November 2019

Winter squash (Cucurbita maxima) is produced in Oregon’s Willamette Valley for edible seeds, processing, and fresh markets. Recently, prominent cultivar Golden Delicious has experienced significant yield losses due to a soilborne disease. Symptoms include stunting, root and crown rot, vascular discoloration, and late-season vine collapse. To identify potential causal pathogens, 64 fields were surveyed during 2014 to 2016 to characterize the fungal community associated with surface-disinfested root, crown, and stem tissue of diseased and healthy squash. Over 10,000 fungal isolates were identified morphologically, and 1,783 isolates were identified to species by sequencing of internal transcribed spacer and translation elongation factor 1 alpha genomic regions. Fungal communities were analyzed for association with the presence or absence of field symptoms using multivariate community analyses (indicator species analysis, multiresponse permutation procedure, and nonmetric multidimensional scaling). Although no fungal species were consistently associated with disease, five species were consistently isolated from plants regardless of the presence of symptoms and were capable of causing disease in a greenhouse pathogenicity trial: Fusarium oxysporum, F. solani, F. culmorum, Plectosphaerella cucumerina, and Setophoma terrestris. Results from community analyses confirmed that some fungi were more common in specific tissues (e.g., P. cucumerina in stems and crown, F. solani in roots and crown). Symptom severity tended to be greater in fields with a prior history of squash production, although a few fields with no prior history of squash had above average symptom ratings. The results from this study suggest that the five most common fungi may take on greater disease significance when they co-occur in a host.
How BamA recruits OMP substrates via poly‐POTRAs domain
Authors: Ma Xiaodan , Wang Qianqian , Li Yuwen , Tan Pan , Wu Haiyan , Wang Pengran , Dong Xue , Hong Liang , Meng Guoyu
Published: November 2019

Almost all the outer membrane proteins (OMPs) fold into an invariant β‐barrel fold via the polypeptide‐transport‐associated (POTRA) motif and β‐barrel assembly machinery (BAM). However, whether and how poly‐POTRAs interact with OMPs remain largely unknown. Here, we have characterized the structures of Haemophilus influenzae poly‐POTRAs via X‐ray crystallography, small angle X‐ray scattering, and molecular dynamics simulation. Unexpectedly, crystal packing reveals a putative OMP travel pathway spiraled by the conserved α2‐β2 edges in poly‐POTRAs. Supportively, the structure‐based mutations targeting the OMP binding sites significantly disrupt OMP biogenesis, resulting in severe cell growth defects. Another notable feature in H. influenzae POTRA structures is flexibility. As characterized by ELISA assays, poly‐POTRAs could recruit OMP substrates in a step‐wise manner. More importantly, the restriction of POTRA‐POTRA linkage and flexibility significantly impairs the BamA function and causes cell growth defect. Altogether, these results suggest that the β‐strand augmentations and intrinsic flexibility are important factors for BamA‐OMP recruitment.—Ma, X., Wang, Q., Li, Y., Tan, P., Wu, H., Wang, P., Dong, X., Hong, L., Meng, G. How BamA recruits OMP substrates via poly‐POTRAs domain. FASEB J. 33, 14690‐14702 (2019). www.fasebj.org