bluuebunny/crossref_metadata_2025 huggingface dataset:
Extremely hidden multi-stability in a class of two-dimensional maps with a cosine memristor
Authors: Zhang Li-Ping , Liu Yang , Wei Zhou-Chao , Jiang Hai-Bo , Lyu Wei-Peng , Bi Qin-Sheng
Published: May 2022

We present a class of two-dimensional memristive maps with a cosine memristor. The memristive maps do not have any fixed points, so they belong to the category of nonlinear maps with hidden attractors. The rich dynamical behaviors of these maps are studied and investigated using different numerical tools, including phase portrait, basins of attraction, bifurcation diagram, and Lyapunov exponents. The two-parameter bifurcation analysis of the memristive map is carried out to reveal the bifurcation mechanism of its dynamical behaviors. Based on our extensive simulation studies, the proposed memristive maps can produce hidden periodic, chaotic, and hyper-chaotic attractors, exhibiting extremely hidden multi-stability, namely the coexistence of infinite hidden attractors, which was rarely observed in memristive maps. Potentially, this work can be used for some real applications in secure communication, such as data and image encryptions.
Surface structure modification of ReSe2 nanosheets via carbon ion irradiation
Authors: Qiao Mei , Wang Tie-Jun , Liu Yong , Liu Tao , Liu Shan , Xu Shi-Cai
Published: May 2022

The effects of C ion irradiation on multilayer ReSe2 flakes are studied by utilizing different kinds of technologies. The domain sizes, thickness, morphologies of the multilayer ReSe2 flakes on the Al2O3 substrates before and after 1.0-MeV C ion irradiation with different fluence rates are studied by atomic force microscope and scanning electron microscopy. The atomic vibrational spectra of multilayer ReSe2 flakes are detected by micro-Raman spectra. The redshifts of the Raman modes after 1.0-MeV C ion irradiation are observed from the micro-Raman spectra. The elemental compositions and bonding configurations of the multilayer ReSe2 samples before and after irradiation processes are characterized by x-ray photoelectron spectroscopy. The structural properties are also investigated by x-ray diffraction, and it is concluded that after 1.0-MeV C ion irradiation process, multilayer ReSe2 samples continue to grow on Al2O3 substrates, the increase of crystallite size also reveals that the crystallinity is improved with the increase of the layer number after 1.0-MeV C ion irradiation.
Avian whiffling-inspired gaps provide an alternative method for roll control
Authors: Sigrest Piper , Inman Daniel J
Published: May 2022

Some bird species exhibit a flight behavior known as whiffling, in which the bird flies upside-down during landing, predator evasion, or courtship displays. Flying inverted causes the flight feathers to twist, creating gaps in the wing’s trailing edge. It has been suggested that these gaps decrease lift at a potentially lower energy cost, enabling the bird to maneuver and rapidly descend. Thus, avian whiffling has parallels to an uncrewed aerial vehicle (UAV) using spoilers for rapid descent and ailerons for roll control. However, while whiffling has been previously described in the biological literature, it has yet to directly inspire aerodynamic design. In the current research, we investigated if gaps in a wing’s trailing edge, similar to those caused by feather rotation during whiffling, could provide an effective mechanism for UAV control, particularly rapid descent and banking. To address this question, we performed a wind tunnel test of 3D printed wings with a varying amount of trailing edge gaps and compared the lift and rolling moment coefficients generated by the gapped wings to a traditional spoiler and aileron. Next, we used an analytical analysis to estimate the force and work required to actuate gaps, spoiler, and aileron. Our results showed that gapped wings did not reduce lift as much as a spoiler and required more work. However, we found that at high angles of attack, the gapped wings produced rolling moment coefficients equivalent to upwards aileron deflections of up to 32.7° while requiring substantially less actuation force and work. Thus, while the gapped wings did not provide a noticeable benefit over spoilers for rapid descent, a whiffling-inspired control surface could provide an effective alternative to ailerons for roll control. These findings suggest a novel control mechanism that may be advantageous for small fixed-wing UAVs, particularly energy-constrained aircraft.
In vitro static and dynamic cell culture study of novel bone scaffolds based on 3D-printed PLA and cell-laden alginate hydrogel
Authors: Noroozi Reza , Shamekhi Mohammad Amin , Mahmoudi Reza , Zolfagharian Ali , Asgari Fatemeh , Mousavizadeh Ali , Bodaghi Mahdi , Hadi Amin , Haghighipour Nooshin
Published: May 2022

The aim of this paper was to design and fabricate a novel composite scaffold based on the combination of 3D-printed polylactic acid-based triply periodic minimal surfaces (TPMSs) and cell-laden alginate hydrogel. This novel scaffold improves the low mechanical properties of alginate hydrogel and can also provide a scaffold with a suitable pore size, which can be used in bone regeneration applications. In this regard, an implicit function was used to generate some gyroid TPMS scaffolds. Then the fused deposition modeling process was employed to print the scaffolds. Moreover, the micro computed tomography technique was employed to assess the microstructure of 3D-printed TPMS scaffolds and obtain the real geometries of printed scaffolds. The mechanical properties of composite scaffolds were investigated under compression tests experimentally. It was shown that different mechanical behaviors could be obtained for different implicit function parameters. In this research, to assess the mechanical behavior of printed scaffolds in terms of the strain–stress curves on, two approaches were presented: equivalent volume and finite element-based volume. Results of strain–stress curves showed that the finite-element based approach predicts a higher level of stress. Moreover, the biological response of composite scaffolds in terms of cell viability, cell proliferation, and cell attachment was investigated. In this vein, a dynamic cell culture system was designed and fabricated, which improves mass transport through the composite scaffolds and applies mechanical loading to the cells, which helps cell proliferation. Moreover, the results of the novel composite scaffolds were compared to those without alginate, and it was shown that the composite scaffold could create more viability and cell proliferation in both dynamic and static cultures. Also, it was shown that scaffolds in dynamic cell culture have a better biological response than in static culture. In addition, scanning electron microscopy was employed to study the cell adhesion on the composite scaffolds, which showed excellent attachment between the scaffolds and cells.
A meta-analytical review of intervention experiments to reduce food waste
Authors: Tian Xi , Xia Ziqian , Xie Jinliang , Zhang Chao , Liu Yaobin , Xu Ming
Published: May 2022

To reduce food waste, many behavioural intervention experiments have been conducted worldwide, but their effectiveness remains unclear. To assess their impacts, we present a meta-analysis based on 58 studies, selected after screening 1143 papers, which were conducted between 2011 and 2021 covering 26 533 participants. We confirm that behavioural interventions have a moderate effect (

z

= 0.22) on food waste reduction, with education programs having the most significant impact and informational feedback having the least. We also show that interventions in elementary and middle school settings marginally improve the overall effect size (P < 0.1), and controlled experiments exhibit a higher effect size compared to pre-post experiments in education interventions (P < 0.05). Finally, we present a roadmap to guide future research in the next decade to further improve our understanding on the effects of behavioural interventions to reduce food waste.
Local order metrics for two-phase media across length scales*
Authors: Torquato Salvatore , Skolnick Murray , Kim Jaeuk
Published: May 2022

The capacity to devise order metrics to characterize and classify microstructures of multiphase heterogeneous media across length scales is an outstanding but highly challenging task, given the richness of the possible geometries and topologies of the phases that can arise. This investigation initiates a program to formulate order metrics to characterize the degree of order/disorder of the microstructures of two-phase media in

d

-dimensional Euclidean space

R

d

across length scales. In particular, we propose the use of the local volume-fraction variance

σ

V

2

(

R

)

associated with a spherical window of radius R as an order metric. We determine

σ

V

2

(

R

)

as a function of

R

for 22 different models across the first three space dimensions, including both hyperuniform and nonhyperuniform systems with varying degrees of short- and long-range order. We find that the local volume-fraction variance as well as asymptotic coefficients and integral measures derived from it provide reasonably robust and sensitive order metrics to categorize disordered and ordered two-phase media across all length scales. Such order metrics could be employed to accelerate the discovery of novel heterogeneous materials by tailoring their degree of order/disorder.
Problems of realization of low-productivity oil wells continuous operation
Authors: Tsylev P N , Shchapova I N , Shchapov V A
Published: May 2022

The expediency of low-productivity oil wells continuous operation has been specified. The analysis of possible ways of transferring oil wells with low flow rate to continuous operation is given. We noted the most rational use of low-speed asynchronous electric motors in the electric drive of plunger pumps. The problems of low-speed asynchronous electric motors development and production have been considered. The emphasis is placed on high weight, size and cost parameters of low-speed asynchronous electric motors and low values of their efficiency and power factor. A number of possible solutions to these problems are proposed. Thus, it is recommended to use a stator winding with a shortened pole pitch length to improve the weight, size and cost parameters. Reduction of electrical and magnetic loads and the use of copper instead of aluminum as a stator and rotor windings material contribute to the increase of the efficiency factor. The use of internal compensation of magnetizing current and reactive power is aimed at achieving the power factor values close to one.
Application of statistical dependencies to evaluate economic indicators of production efficiency by the example of oil fields in Azerbaijan
Authors: Safarov Q A , Vagif gizi G , Galkin S V
Published: May 2022

Improving the use of basic funds and production capacity in oil and gas recovery is not only the introduction of new techniques and technology, but also the improvement of labor, management and organization of work. The process of renewal of the fixed capital and production forces is considered intensive at the time when the vast majority of the newly incorporated basic funds and forces are aimed at replacement of morally obsolete and physically worn out parts. This time, their compliance with the economically justified life expectancy is of interest. All these are elements of recycling. Oil and gas wells are important elements of the active part of the main production funds and they determine the future development of oil and gas recovery. Productive use of production wells for oil and gas recovery is considered as a source of improvement of production efficiency in terms of production-resource potential (PRP). In order to increase the efficient use of oil and gas wells as an active element of the main production funds, special attention is paid to both extensive and intensive factors at oil and gas production enterprises.
Differentiation of exploration and production wells to prevent the breakthrough of water injected into the reservoir
Authors: Mukhametshin V V , Kuleshova L S
Published: May 2022

The equations of canonical discriminant functions and distributions were derived for deposits of the Tournaisian age of the Volga-Ural oil and gas province. This enables solution to the problems of increasing the efficiency of implementation of various contour waterflood systems, choosing exploration and production wells for focal waterflood, and estimation of the well grid density at the stage of preparation of the design documents, pressure and injection volumes, as well as making scientifically grounded management decisions for regulating the exploitation process. The method has been proposed to prevent a catastrophic breakthrough of water injected into the reservoir, which is the reason for a significant decrease in the degree of oil reserves recovery.
Probabilistic and statistical justification of the forecast of oil and gas potential in the area with established industrial oil capacity
Authors: Krysin N N , Sologubova M V
Published: May 2022

The article provides an example of an integrated approach to geological exploration in an area with an established industrial oil capacity. This approach is based on the analysis of the geological structure of the area under consideration and the stochastic assessment of the resources of the prospects using the Monte-Carlo simulation. Within the area under consideration, two regions were allocated for separate forecasting of the oil and gas potential of the prospects: south-western and north-eastern. Potentially oil and gas-bearing structures have been established in each region: in the south-western region, all structures are classified as unpromising, in the north-eastern region – as exploration targets. For each structure in the north-eastern region, possible oil-bearing areas were calculated, analog fields were selected for the probabilistic assessment of the prepared resources using the Monte-Carlo simulation. Based on the results of the evaluation, the most exploration target was selected.
Justification of the use of a supersonic separator at the Yu. Kuvykin gas condensate field
Authors: Kirsanov D V , Leticheskaya N N
Published: May 2022

The main trends in the advancement of technology for the development and operation of offshore fields can be called underwater production complexes, which are a system of technological blocks that allow the production and treatment of hydrocarbons on the seabed. This article covers the technology of gas condensate separation using a supersonic separator. This 3S separator is able to perform deep purification of gas condensate with the extraction of CO2 and H2S and can be installed on the shelf as part of an underwater production complex. We consider it possible to apply this technology at the Yu. Kuvykin gas condensate field, which has a positive impact on the realization of the field’s resource potentials.
Evaluation of ways to reduce sand production from unconsolidated heterogeneous formations when using screens
Authors: Khabibullin M Ya
Published: May 2022

Experimental work showed that as a result of placing screens in a well with a bottomhole, the formation of which is composed of inhomogeneous, weakly cemented or loose sandstones, often with reduced permeability due to poor-quality completion, it is necessary to strive for a maximum decrease of ζ2ϕκ due to an increase in the wellbore of the screen shell and thereby an increase in the quality of filtration actions for colmatant breach, which contributes to a decrease of ζ2η. The following conclusions were drawn when examining sand phenomena from weakly cemented and loose formations with a heterogeneity coefficient of more than 10. The particles that make up the rock structure should not be removed from the formation due to the use of a screen. In practice, this means that the screen must not conduct 85-75% (by weight) of the larger sand fractions. To maintain the overall stability of the reservoir skeleton, it is possible to allow the removal of not more than 15-25% (in weight) of fine particles.
The structure and bearing capacity of rock structures during underground mining
Authors: Zaalishvili V B , Burdzieva O G , Khaliev M S-U
Published: May 2022

The processes of controlling the ore-containing mass are refined and detailed, and the mechanism of interaction of stresses and deformations during underground mining of ore deposits is detailed. The properties of the massif and the role of faults and macrofractures in the development of deposits of complex structure are systematized. A methodology for studying stresses and deformations of rocks is given. Regularities of array maintenance at the interface site are established. Quantitative values of changes in physical and mechanical properties and stability of rocks in the interface zone are given. The array is differentiated by the magnitude of the acting stresses in various phases of the connection. The calculation of stresses for specific conditions with the determination of the reliability of the mining site was performed. Patterns of stress and strain changes over time are noted. An explanation of the phenomenon is given from the standpoint of the interaction of structural rock blocks in a discrete field of the array.
Improving the efficiency of the physical protection system for oil and gas facilities (by the example of trunk pipelines)
Authors: Tsvetkov G A , Aleshkov A A
Published: May 2022

The article discusses the features of ensuring technospheric safety at oil and gas facilities (using the example of trunk pipelines) in the implementation of national interests. To achieve strategic goals, the developed structure of the physical protection system of trunk pipelines can be used to detect and prevent outside interference in their work, based on the use of passive seismic-analytical and active bioradioinformative methods for monitoring the security zone. An innovative approach is considered, which is based on the effect of the dependence of intruders’ own electromagnetic radiation on the strength of an external low-intensity electromagnetic field of the radio wave range. Its implementation in the creation of technical means provides high selectivity, initially assuming a response only to living organisms, as well as the possibility of classifying biological objects according to their most informative features in any natural and climatic conditions.
A study of the impact of oil recovery on the well grid compaction in the oil-containing layers
Authors: Almukhametova E M , Fayzullin I A
Published: May 2022

The paper examines applications of the technology of compacting the well grid by drilling small-diameter wells in oil-containing layer N and identifies its influence on the oil recovery factor. The effectiveness of the results of grid drilling using small-diameter wells in oil-recoverable reservoir N and an increase in the efficiency of developing the oil-saturated layer by compaction of the existing development grid by drilling small-diameter wells are analyzed. Research methods used are the methods of systems analysis, mathematical modeling; mathematical programming, mathematical statistics, cluster analysis, numerical methods, computational experiments; database design theory.
Possibility of using machine learning algorithms to assess the effectiveness of acid hydraulic fracturing
Authors: Kochnev A A , Torsunova D V , Boyarov V Y , Krivoshchekov S N , Silaev E V
Published: May 2022

At the fields of the Perm Territory, there is a significant application of hydraulic fracturing technology to stimulate the production of carbonate reservoirs. The analysis of the efficiency of the acid hydraulic fracturing technology by the example of the fields of the Perm Territory is presented in the article. The effectiveness of the technology is largely determined by the geological and physical conditions of the fields. Using the methods of mathematical statistics, the main geological and physical parameters which most significantly affect the effectiveness of measures for acid hydraulic fracturing have been identified. A multiple regression model was built to find out the complex influence of the parameters on the increase in oil production after the measures. Various machine learning algorithms have been used to predict the increase in oil and fluid input rates after acid fracturing. Different algorithms showed different results. For the problems of forecasting oil production after the application of acid fracturing, the most successful one was the support vector method.
Paleogeographic reconstructions of Emsian - Lower Frasnian formation for oil and gas prospecting
Authors: Pleshkov L D , Kozhevnikova E E
Published: May 2022

The reconstruction of sedimentation conditions is very important for understanding the geological structure of the region, for assessing the generative potential of the formation, and for the design of prospecting works for oil and gas. In this work we reconstruct the paleo-geographic conditions of Emsian – Lower Frasnian formation identifying zones with conditions for the formation of reservoirs, seals and hydrocarbon bearing rocks. The accumulated data on the oil and gas content of the territory were summarized what made it possible to divide the oilfields into several groups with different sources of oil generation. In the conclusion, we allocated zones promising for oil deposits in Devonian Terrigenous formation on the territory of Perm Krai and Udmurt Republic.
Indirect determination of reservoir pressure by changing operating modes of exploration and recovery wells
Authors: Grishchenko V A , Kharisov M N , akupov R F Y , Mukhametshin V V , Kuleshova L S
Published: May 2022

The results obtained in the article enable to draw a conclusion about the sufficient accuracy of assessing the energy state and the possibility of using an algorithm for the indirect determination of reservoir pressure for solving practical problems of geological exploration and geological recovery research in selecting and planning geological and engineering operations and monitoring the work of the base well stock. However, algorithms for indirect determination of reservoir pressure should not fully replace well testing but they can be considered as an additional tool for assessing the reservoir pressure and their results should be analyzed considering the experience of the reservoir development in specific geological conditions.
Study of the reliability of the determination of reservoir characteristics of productive formations in the Stretenskoye field using correlation analysis
Authors: Chukhlov A S , Galkin V I , Ponomareva I N , Chernykh V I
Published: May 2022

Storage properties (porosity) of productive strata at Stretenskoye field were determined using several methods of geophysical studies of wells. The filtration properties (permeability) are determined according to the interpretation of the hydrodynamic study materials under unsteady conditions. At the same time, the methods used in a number of cases showed different results. In order to avoid misinterpretation of the structure of void space and its properties, it is advisable to conduct studies to assess the reliability of all the methods. For this purpose, the paper used the tools of mathematical statistics such as correlation and multivariate regression analysis. As a result of the research, the authors gave the recommendations for the application of methods to determine the filtration and storage properties of reservoirs differentially for terrigenous and carbonate reservoirs of the studied field.
Microbiological and physicochemical treatment of oil to increase field resource extraction
Authors: Veliev M M , Veliev E M , Mukhametshin V V , Kuleshova L S , Zung Le Viet , Akhmetshina D I
Published: May 2022

It was shown that the use of a physicochemical microbiological composition (FCMC) revealed a slight change in the amount of sulphate-reducing bacteria. The mineralization and density of the fluid taken from production wells before and after injection of this composition almost did not changed. After the FCMC injection, the watering of the pilot site slowed down. The calculations showed that the accumulated additional oil production of the pilot site during the period under study will be 856 tons and is increasing. These initial results suggest further effective application of the technology to other similar facilities.
Estimation of the optimal direction of the horizontal borehole relative to the minimum and maximum formation stress
Authors: Bosikov I I , Egorova E V , Karpikov A V
Published: May 2022

The article discusses the analysis and assessment of the optimal direction of the horizontal wellbore and its spatial location relative to the minimum and maximum reservoir stresses play a significant role in the design of an operation to create multiple hydraulic fractures. Theoretically, two cases are possible: the horizontal wellbore is located strictly in the direction of maximum horizontal stress; the horizontal wellbore is located strictly in the direction of the minimum horizontal stress. As a conclusion based on the hydraulic fracturing design, the well productivity factor was calculated and compared for longitudinal and transverse fractures; longitudinal fractures have a clear advantage. According to the presented calculation, the hydraulic fracturing method will have advantages in a horizontal well in a highly permeable reservoir. The hydraulic fracturing method will increase the vertical permeability. According to the presented calculation, the hydraulic fracturing method will have advantages in a horizontal well in a highly permeable reservoir. The hydraulic fracturing method will increase the vertical permeability and unite the disparate parts of the reservoir. The hydraulic fracturing method will increase the vertical permeability and unite the disparate parts of the reservoir, which will make it possible to more efficiently develop the reserves of the Neocomian deposits in the field.
Investigation of the influence of the drive shaft speed on the characteristics of a submersible pump when pumping out a gas-liquid mixture
Authors: Odintsov A A , Musinskii A N , Ostrovskii V G
Published: May 2022

The article presents the results of small size ESP (electrical submersible pump) tests at a speed of 6000-8500 rpm in the presence of free gas at the inlet to the device. The submersible centrifugal pump is quite sensitive to the presence of free gas in the pumped gas-liquid mixture. Depending on the amount of free gas, the actual characteristics of the pump are deformed, and at a certain gas content, the pump stops supplying the gas-liquid mixture. Stable operation of the ESP is carried out with a free gas content at the pump inlet ranging from 5% to 25%, depending on the pump size. There are several ways to deal with gas in wells operated by ESP: from running the pump into the zone where the intake pressure ensures optimal pump flow and stable operation to the use of separating and dispersing devices at the intake. Results represent pump flow characteristics along with different inlet free gas contents.
Analysis and forecasting of the success of hydraulic fracturing treatment in the selection of candidate wells
Authors: Anisimov V V , Mukhametshin V Sh , Valeev A I
Published: May 2022

At present, a huge part of oil and gas reserves are hard-to-recover, that is, they are located in deposits being classified as low-permeability reservoirs. A detailed analysis of the success of previously conducted hydraulic fracturing treatment of reservoirs in the wells of the explored production facility, as well as the methodology approbation for the assessment and selection of design candidate wells for further HFT in this field are considered in the paper.
Telemetry system based on fiber-optic gyroscopes
Authors: Melekhin A A , Riabokon E P , Krivoshchekov S N
Published: May 2022

The article presents a telemetry system for monitoring the bit trajectory during well drilling. Fiber-optic closed-loop gyroscopes are the main sensitive element in the telemetry system. The gyroscopes allow determining the azimuth and zenith angles of the well with a high accuracy exceeding most magnetometers. There is no need to use the expensive non-magnetic steels in the body of the telemetry system and non-magnetic drill pipes in the drill string. Fiber-optic closed-loop gyroscopes allow using the telemetry system when drilling near the casing of adjacent wells and magnetized rocks. An inertial navigation system is installed in the developed telemetry system as a measuring unit containing three angular velocity sensors and three accelerometers mounted rigidly. The sequence and results of simulation of a hydraulic link for data transmission from the bottom of the well to the top are described. Pilot tests of the telemetry system were carried out at well No. 450 of the Tatsuksinskoye field. The obtained values of the spatial intensity of the borehole curvature in depth are close in values to the directional survey data for the borehole. The trajectory obtained during the lift is close to the trajectory gathered from directional survey data.
Influence of oil structures on the component composition of free gases of potash reservoirs at the BPPU-4 mine field of PJSC “Uralkali”
Authors: Papulov A S , Andreyko S S , Ivanov O V
Published: May 2022

The influence of oil structures on the content of heavy hydrocarbon gases in the component composition of free gases in the rocks of the overlying silvinite formations is considered. There is an assumption about the influence of reef formations on the overlying sedimentary deposits and the development of sub-vertical cracks, through which heavy hydrocarbon gases can penetrate into the overlying potash layers. The aim of the study is to study the relationship between the nature of the distribution of heavy hydrocarbon gases and geological disturbances and the subsequent prediction of the gas-dynamic situation during the development of potash reservoirs. The method consists of drilling holes into the roof of the mine, sealing the hole with a sealer, and then taking gas from the sealed part to the sampler and analyzing it on a gas chromatograph. The highest values of heavy hydrocarbon gases were determined for the Bc, AБ and KpII formations at the BPPU-4 mine field of PJSC Uralkali.
Impact of hydraulic fracturing on the creation of highly permeable channels within the Earth’s interior
Authors: Khalikova K M , Almukhametova E M , Gutorov A Y
Published: May 2022

in modern times hydrocarbon production in fields with hard-to-recover reserves is actively being implemented. This trend is caused by the depletion of conventional reserves, which increases every year of operation. In Russia, most of the hard-to-recover reserves belong to deposits with low-permeability channels and deteriorated reservoir properties. The cost-effective utilization of such subsoil resources is only possible using special technologies that can increase well productivity. One of the most commonly used technologies is hydraulic fracturing (HFT). This study analyzed the impact of HFT on the creation of highly permeable channels as a stimulation method. The methodology for the selection of well candidates for HFT was identified, its effectiveness and practical significance were evaluated.
Improvement of operational efficiency of high water-cut oil wells
Authors: Raupov I R , Milic J
Published: May 2022

This paper describes a new algorithm for selecting candidate wells for water shut-off works. A new comprehensive methodology for the selection of candidate wells for water shut-off technology is proposed, consisting of 4 stages, where wells with excessive water cut are identified. The reasons for the water cut are determined, and the effectiveness of water shut-off technology on a potential candidate well is substantiated and predicted. The proposed method has been tested by the example of two wells in terrigenous reservoirs of a gas-oil field.
One-pot hydrothermal synthesis of Co–Ni hexacyanoferrate nanocuboids on Ni-foam as efficient catalysts for oxygen evolution and urea oxidation reactions
Authors: Reddy Bommireddy Purusottam , Suh Youngsuk , Park Si-Hyun
Published: May 2022

Recently, considerable research has been conducted on Prussian blue analogues (PBAs), a type of metal-organic framework (MOF) material, as novel electrocatalysts for oxygen evolution reactions (OERs) and urea oxidation reactions (UORs). In the present work, considering Co–Ni hexacyanoferrate (CoxNi1−xHCF) as a PBA, CoxNi1−xHCF nanocuboids with different Co and Ni compositions were synthesized on Ni foam (NF) by hydrothermal synthesis. Further, their application toward OER and UOR catalytic activity was studied. The synthesized CoxNi1−xHCF:NF composites with high catalytic activity and conductivity exhibited superior catalytic performance for the OERs and UORs. The CoxNi1−xHCF:NF composite electrodes exhibited a lower overpotential (η) of 334 mV with a lower Tafel slope of 72 mV dec−1 for the OER catalytic activity and a lower potential of 1.38 V with a lower Tafel slope of 50 mV dec−1 for the UOR catalytic activity. It was observed that low charge transfer resistance, high electrochemically active surface area, and availability of Co3+ ions are major factors contributing to the OER activity. The presence of oxidative Ni2+ species contributed significantly to the UOR activity. Overall, the present study elucidates the binder-free CoxNi1−xHCF:NF electrodes as stable and high-performance OER and UOR catalysts and provides pathways for designing advanced PBA catalysts.
Accurate parametrization revealing an extremely low disorder in polymer field-effect transistors
Authors: Romanjek Krunoslav , Charbonneau Micaël , Kim Chang-Hyun
Published: May 2022

In this paper, a robust self-consistent parameter extraction method is applied to high-performance p-type printed polymer field-effect transistors. Simultaneous extraction of contact resistance and intrinsic channel mobility with their full gate-voltage dependence is achieved through an analytically reinforced transmission-line method. The proposed method yields a minimum width-normalized contact resistance of 12 kΩ cm and a maximum hole mobility of 1.9 cm2 V−1 s−1. Moreover, the gate-voltage-dependent mobility is interpreted in the framework of trap-and-release transport through double-exponential density of states, unveiling a disorder energy near the transport orbital as low as 29 meV.
Evaluation of Mycobacterium Avium Complex Pulmonary Disease Treatment Completion and Adherence to ATS/IDSA Guidelines
Authors: Ku Jennifer H , Henkle Emily , Carlson Kathleen F , Marino Miguel , Brode Sarah K , Marras Theodore K , Winthrop Kevin L
Published: May 2022

Background

Nontuberculous mycobacteria are environmental organisms that cause infections leading to chronic, debilitating pulmonary disease, among which Mycobacterium avium complex (MAC) is the most common species.

Methods

We described patterns of macrolide-based multidrug antibiotic therapies for MAC pulmonary disease (MAC-PD) in US Medicare beneficiaries with bronchiectasis between January 2006 and December 2014. MAC therapy was defined as a multidrug regimen containing a macrolide plus ≥1 other drug targeting MAC-PD (rifamycin, ethambutol, fluoroquinolone, or amikacin) prescribed concomitantly for >28 days.

Results

We identified 9189 new MAC therapy users, with a mean age (standard deviation) of 74 (6 years) at the start of therapy; 75% female and 87% non-Hispanic white. A guideline-based regimen (a macrolide, ethambutol, and rifamycin, with or without amikacin) was prescribed for 51% of new MAC therapy users at treatment start, of whom 41% were continuing guideline-based therapy at 6 months, and only 18% at 12 months. Of all new MAC therapy users, by 18 months only 11% were still receiving MAC treatment, 55% had discontinued therapy, and 34% were censored owing to death or the end of the study period.

Conclusions

Overall, nearly half of new MAC therapy users were prescribed a non–guideline-recommended macrolide-based therapy, including regimens commonly associated with promoting macrolide resistance. Treatment discontinuation was common, and once discontinued, only a few beneficiaries resumed therapy at a later time. Our study adds important data to the current literature on treatment patterns for MAC-PD among older US populations. Future research should examine treatment patterns using more contemporary data sources.
Pharmacological cardioversion of supraventricular tachycardia in pregnancy during continuous electrophysiological foetal monitoring: a case report
Authors: Francinetti Audrey , Vullings Rik , Dewals Wendy , Jochems Lisbeth
Published: May 2022

Background

Maternal tachycardia is the most frequently occurring cardiac complication during pregnancy. Often administration of drugs is required as a treatment. The drug of choice is intravenously administered adenosine because it is considered safe, though there are limited studies regarding safety for the foetus with the use of adenosine.

Case summary

We report a conversion of maternal atrio-ventricular (AV) nodal reentry tachycardia during pregnancy with the use of intravenous adenosine whilst continuous electrophysiological foetal monitoring. Four seconds after the maternal conversion, the foetal tracing suggests the presence of a ventricular extrasystole or a transient AV block.

Discussion

This case report illustrates that the administration of adenosine intravenously during pregnancy could have an effect on the foetal conduction system. Therefore, further investigation to assess the electrophysiological effect of adenosine on the foetal electrocardiogram seems required.
Modeling Advance Oak Reproduction at Landscape Scale: The Relative Importance of Abiotic and Biotic Factors
Authors: Rittenhouse Joshua W , Leites Laura P
Published: May 2022

Establishing advance oak reproduction in the understory of mature oak forests before an overstory removal is critical to regenerate mixed-oak forests (Quercus spp.). Many studies have been conducted at the stand scale; however, studies at landscape scale can be particularly useful to guide silvicultural management investments. We developed a model of advance reproduction abundance at landscape scale using inventory, climate, topography, and soils data from ninety-seven mixed-oak forests located in Pennsylvania, USA. A negative binomial model was used to predict the abundance of oak seedlings between 15.2 and 91.4 cm in height and with a root collar diameter of 0.64 to 1.9 cm (established oak seedlings). This model had a Nagelkerke’s pseudo R2 of 58%. Deviance partitioning methods indicate that climate and overstory influence explain similar proportions of total deviance, but climate contributes a higher proportion of nonoverlapping information (22% versus 18%). Overstory basal area of two common oak species were positively associated with seedling abundance, whereas biotic stressors were negatively correlated. Biotic stressors showed considerable overlap with information provided by climate and overstory influences. The results of this study provide a reference to guide silvicultural management at a landscape scale.
Best Management Practices, Estimated Erosion, Residual Woody Debris, and Ground Cover Characteristics Following Biomass and Conventional Clearcut Harvests in Virginia’s Mountains
Authors: Garren Austin M , Bolding M Chad , Barrett Scott M , Aust W Michael , Coates T Adam
Published: May 2022

Water quality best management practices (BMPs) developed for conventional forest harvests may be adequate for biomass harvests, yet quantitative data is lacking. This study compared estimated erosion, operational feature areas, BMP implementation rates, ground cover characteristics, and downed woody debris quantities following biomass and conventional harvests in the mountains of Virginia. Haul roads on biomass harvests had significantly higher estimated erosion rates (P = 0.064) and masses (P = 0.045) than conventional harvests, but conventional harvests had higher erosion contributions from skid trails (P = 0.089) and averaged more estimated erosion mass overall, despite being significantly smaller in size (P = 0.054). There was significantly less area in heavy slash (P = 0.076) and lower estimated mass of residual downed woody debris (P = 0.001) on biomass sites than conventional sites (10.98 and 27.95 tons/ac, respectively). Site-wide BMP implementation scores (P = 0.041), streamside management zones (SMZs) (P = 0.024), and skidding (P = 0.063) were significantly higher on biomass sites than conventional sites. BMP implementation scores were significant predictors of estimated erosion rates (P < 0.001, R2 = 59%), indicating that adequate levels of existing water quality BMPs are effective for erosion control on both conventional and biomass harvests.
An Inverse Growth Curve Representation of the Clutter-Jones Stand Survival Model
Authors: Wang Mingliang , Montes Cristian R , Bullock Bronson P , Zhao Dehai
Published: May 2022

The Clutter-Jones (CJ) stand survival model has been widely used for the projection of the reduction in trees per unit area in a forest stand over time. To better understand this well-recognized model, we introduced a varying-parameter formulation as an alternative to its original difference equation form, where plot-specific effects are presented explicitly. This new parameterization turns out to be a type of Richards (generalized logistic) equation with its independent variable age log-transformed, which might be termed “log-Richards” (LR) and falls into the category of the generalized algebraic difference approach (GADA) models. Under the LR GADA representation, a half-reduction age, at which half of the trees in a stand die, may be examined to improve stand survival simulation. The new reformulation provides an inverse growth curve modeling viewpoint of stand survival over time. It may motivate one to derive new survival models directly from existing growth equations that allow for generating inverse growth curves, complementary to the commonly used differential equation method in developing stand mortality models.

Study Implications: The Clutter-Jones stand survival model plays an important role in southern pine plantation management as a component of whole-stand modeling systems. This study introduces a varying-parameter formulation as an alternative to its original difference equation form, providing an inverse growth curve modeling viewpoint of stand survival over time.
Genome sequences of 24 Aspergillus niger sensu stricto strains to study strain diversity, heterokaryon compatibility, and sexual reproduction
Authors: Seekles Sjoerd J , Punt Maarten , Savelkoel Niki , Houbraken Jos , Wösten Han A B , Ohm Robin A , Ram Arthur F J
Published: May 2022

Mating-type distribution within a phylogenetic tree, heterokaryon compatibility, and subsequent diploid formation were studied in 24 Aspergillus niger sensu stricto strains. The genomes of the 24 strains were sequenced and analyzed revealing an average of 6.1 ± 2.0 variants/kb between Aspergillus niger sensu stricto strains. The genome sequences were used together with available genome data to generate a phylogenetic tree revealing 3 distinct clades within Aspergillus niger sensu stricto. The phylogenetic tree revealed that both MAT1-1 and MAT1-2 mating types were present in each of the 3 clades. The phylogenetic differences were used to select for strains to analyze heterokaryon compatibility. Conidial color markers (fwnA and brnA) and auxotrophic markers (pyrG and nicB) were introduced via CRISPR/Cas9-based genome editing in a selection of strains. Twenty-three parasexual crosses using 11 different strains were performed. Only a single parasexual cross between genetically highly similar strains resulted in a successful formation of heterokaryotic mycelium and subsequent diploid formation, indicating widespread heterokaryon incompatibility as well as multiple active heterokaryon incompatibility systems between Aspergillus niger sensu stricto strains. The 2 vegetatively compatible strains were of 2 different mating types and a stable diploid was isolated from this heterokaryon. Sclerotium formation was induced on agar media containing Triton X-100; however, the sclerotia remained sterile and no ascospores were observed. Nevertheless, this is the first report of a diploid Aspergillus niger sensu stricto strain with 2 different mating types, which offers the unique possibility to screen for conditions that might lead to ascospore formation in A. niger.
Histone variant H2A.Z promotes meiotic chromosome axis organization in Saccharomyces cerevisiae
Authors: Chigweshe Lorencia , MacQueen Amy J , Holmes Scott G
Published: May 2022

Progression through meiosis is associated with significant reorganization of chromosome structure, regulated in part by changes in histones and chromatin. Prior studies observed defects in meiotic progression in yeast strains lacking the linker histone H1 or variant histone H2A.Z. To further define the contributions of these chromatin factors, we have conducted genetic and cytological analysis of cells undergoing meiosis in the absence of H1 and H2A.Z. We find that a spore viability defect observed in strains lacking H2A.Z can be partially suppressed if cells also lack histone H1, while the combined loss of both H1 and H2A.Z is associated with elevated gene conversion events. Cytological analysis of Red1 and Rec8 staining patterns indicates that a subset of cells lacking H2A.Z fail to assemble a proper chromosome axis, and the staining pattern of the synaptonemal complex protein Zip1 in htz1Δ/htz1Δ cells mimics that of cells deficient for Rec8-dependent meiotic cohesion. Our results suggest a role for H2A.Z in the establishment or maintenance of the meiotic chromosome axis, possibly by promoting the efficient chromosome cohesion.
Fine-tuning acetyl-CoA carboxylase 1 activity through localization: functional genomics reveals a role for the lysine acetyltransferase NuA4 and sphingolipid metabolism in regulating Acc1 activity and localization
Authors: Pham Trang , Walden Elizabeth , Huard Sylvain , Pezacki John , Fullerton Morgan D , Baetz Kristin
Published: May 2022

Acetyl-CoA Carboxylase 1 catalyzes the conversion of acetyl-CoA to malonyl-CoA, the committed step of de novo fatty acid synthesis. As a master regulator of lipid synthesis, acetyl-CoA carboxylase 1 has been proposed to be a therapeutic target for numerous metabolic diseases. We have shown that acetyl-CoA carboxylase 1 activity is reduced in the absence of the lysine acetyltransferase NuA4 in Saccharomyces cerevisiae. This change in acetyl-CoA carboxylase 1 activity is correlated with a change in localization. In wild-type cells, acetyl-CoA carboxylase 1 is localized throughout the cytoplasm in small punctate and rod-like structures. However, in NuA4 mutants, acetyl-CoA carboxylase 1 localization becomes diffuse. To uncover mechanisms regulating acetyl-CoA carboxylase 1 localization, we performed a microscopy screen to identify other deletion mutants that impact acetyl-CoA carboxylase 1 localization and then measured acetyl-CoA carboxylase 1 activity in these mutants through chemical genetics and biochemical assays. Three phenotypes were identified. Mutants with hyper-active acetyl-CoA carboxylase 1 form 1 or 2 rod-like structures centrally within the cytoplasm, mutants with mid-low acetyl-CoA carboxylase 1 activity displayed diffuse acetyl-CoA carboxylase 1, while the mutants with the lowest acetyl-CoA carboxylase 1 activity (hypomorphs) formed thick rod-like acetyl-CoA carboxylase 1 structures at the periphery of the cell. All the acetyl-CoA carboxylase 1 hypomorphic mutants were implicated in sphingolipid metabolism or very long-chain fatty acid elongation and in common, their deletion causes an accumulation of palmitoyl-CoA. Through exogenous lipid treatments, enzyme inhibitors, and genetics, we determined that increasing palmitoyl-CoA levels inhibits acetyl-CoA carboxylase 1 activity and remodels acetyl-CoA carboxylase 1 localization. Together this study suggests yeast cells have developed a dynamic feed-back mechanism in which downstream products of acetyl-CoA carboxylase 1 can fine-tune the rate of fatty acid synthesis.