bluuebunny/crossref_metadata_2025 huggingface dataset:
Total maximum daily loads of beton reservoir, Gunungkidul Regency, Indonesia during the rainy season
Authors: Firizqi Febby , Widyastuti Margaretha
Published: October 2020

A total maximum daily load (TMDL) is an integrated mechanism to maintain water body to meet the water quality standards of its designated uses. This research was intended to determine the TMDL of Beton Reservoir, a structure built to regulate the water discharge of Beton karst spring in Gunungkidul, Indonesia, especially during the rainy season. The TMDL calculation referred to the Regulation of the Minister of State for Environment No. 28 of 2009 on TMDLs of Lakes and/or Reservoirs that required a calculation of morphological and hydrological characteristics, and water quality to meet Class II standard issued in the Regulation of the Governor of the Special Region of Yogyakarta No. 20 of 2008. The results showed that Beton Reservoir had a total volume of 22 586.83 m3, a surface area of 18 673.12 m2, and a depth of averagely 1.21 m and released water at a rate of 0.48 m3 s–1. From the perspective of quality, the TSS and DO of its water had exceeded the standards, whereas the other parameters: temperature, TDS, pH, BOD, COD, total PO4, and NO3 were within their allowable presence in the water. Based on TMDLs for TSS, DO, BOD, COD, total PO4, and NO3, the Beton Reservoir can no longer accommodate TSS and NO3 while continuing to meet the standards for these pollutants. High levels of TSS and NO3 are attributable to the agricultural activities taking place on the catchment and the flow concentration typical of karst regions.
Assessment of groundwater resources potential using geoelectrical method and slug test in Tegal District, Central Java Province, Indonesia
Authors: Wilopo Wahyu , Rachman Moch Hasmannoor , Putra Doni Prakasa Eka
Published: October 2020

Water resources are essential to support everyone in the world, and one of its sources is groundwater. Many areas in Indonesia rely on groundwater to meet their daily needs due to the lack of surface water resources. However, not all-districts have detail information about groundwater resources such as in Tegal District, Central Java Province, Indonesia. Land use planning without the support of information on water resources will cause many problems. Therefore, this study aims to assess groundwater resources in Tegal District using the geoelectrical method and slug test. The research was conducted by geoelectrical survey in 8 locations, measuring groundwater level from the nearest point, and two slug tests. The result of the survey shows that five types of materials in the area are clay, silt, sand, breccia, and lava. The sand layer is an aquifer, and it consists of two layers. The sand layer has a permeability of 6.68 m d–1. However, the clay has a permeability of 1.46 × 10-3 m d–1. The moderate potential of groundwater resources with transmissivity value of more than 50 m2 d–1 lies in the middle of the district.
How important risk analysis of plastic pollution in coastal area? Case study in Masohi, Central Maluku
Authors: Mutaqin Bachtiar W , Marfai Muh Aris , Helmi Muhammad , Nurhadi Nurhadi , Umarella Muhammad Rizali , Munir Miftakhul
Published: October 2020

Human pressure on the coastal and aquatic surrounding ecosystem in Indonesia, through plastic waste, is increasing, considering that 60 % of the approximately 250 million people live in the coastal areas. Plastic waste originating from human activities has become a massive problem in almost all the small island and coastal regions, especially in the eastern part of Indonesia. This condition is caused by poor waste management and a lack of public awareness in disposing of waste in its place, including in an area known as its marine biodiversities and marine tourism spots like Masohi in Central Maluku. Also, the composition of waste is dominated by plastic waste that cannot be decomposed in a short period, continue circulated on the ocean currents, and will be deposited in coastal areas. Furthermore, some plastic waste will break down into micro-plastics that pollute not only the environment but also marine biota, which are often consumed by humans. This situation profoundly affects the sustainability and function of aquaecosystem services in coastal areas. Therefore, a comprehensive policy and regulation, and interdisciplinary study for analysing vulnerable coastal ecosystem, and mitigating the potential risk of plastic pollution in Masohi, Central Maluku are essential to be conducted.
Local residents’ sense of autonomy towards marine-based adventure tourism development in Ambon
Authors: Umarella Muhammad Rizali , Baiquni Muhammad , Murti Sigit Heru , Marfai Muh Aris
Published: October 2020

Marine-based adventure tourism is one of the fastest growing areas within the world’s largest industry. Regardless the increasing awareness of the economic and environmental significance of adventure marine-based tourism, it is only in recent years that a substantial body of research has developed but mostly still focuses only in the area of the visitors. Meanwhile, the local residents as an important factor who take role in the establishment of adventure marine-based tourism development has little been studied. Therefore, the local residents’ sense of autonomy in developing the marine-based adventure tourism in Ambon was examined by means of qualitative interview study. Data has been collected through semi-structured interviews and field observations. Furthermore, the data has been analysed by inductive analysis. Series of focus group discussions and participatory GIS have been done in order to enrich the data collection process The findings of this study which are three major emergent themes, serve as a basis for the local residents to develop marine-based adventure tourism in a sustainable approach. Their sense of autonomy along with the stakeholders in developing the marine-based adventure tourism will result in more benefits for the visitors as well as the local economy development.
Spatial distribution of slums and its association with disaster vulnerability in Yogyakarta City
Authors: Marwasta Djaka , Rahayu Theresia D. K.
Published: October 2020

Slums commonly distributed in susceptible environment or in location that occupied by low economic household, especially in urban areas. Empirically, in Indonesia, the data about distribution and total area of slums is quite hard to be acquired, since slums indicators is not standardized yet. This study aimed to (1) identify the distribution of slums in Yogyakarta City, based on multi-sources data; and (2) elaborate the linkage between slums location and disaster vulnerability in research area. This research uses a mixed methods, i.e utilization of secondary data, survey method, and GIS mapping. Analysis units of this research are “Kelurahan”, where all “Kelurahan” which have slums are chosen as members of population (census technique). Indepth interview conducted in order to collect disaster vulnerability data in each “Kelurahan”. Informant that chosen as representative person in each “Kelurahan” are “Lurah” or “Secretary of Lurah”. All of the data are analyzed by qualitative and quantitative descriptive method. Conclusion of this study are: (1) Slums in Yogyakarta City distributed mainly along three main rivers, and (2) There are very closed association between slums area and disaster vulnerable zones.
Speleogenetic process of Suaran Block, karst of Sangkulirang–Mangkalihat, East Kalimantan
Authors: Reinhart Hilary , Labib Mohammad Ainul , Haryono Eko
Published: October 2020

Karst of Sangkulirang Mangkalihat is one of the greatest karst areas in Indonesia and has hundreds of caves. Some of those caves are located at Suaran Block, one of the main karst block at this karst. This paper aims to study the speleogenesis process, as the fundamental process on karst landscape and cave development in that area. Speleogenetic process can be examined from the shape of the cave passage using uniformitarianism approach. That principle creates speleomorphology as the study of cave passage form and the factors that affect it. The examination of the cave passages uses cave maps to see the form and direction of them. As the result, caves at Suaran Block are formed mainly driven by geological structures such as fault – fissures and bedding plane which is indicated by linear form of the cave passage and water flow which shows sinusoidal form of the cave passage. Some caves are shaped by the combination of geological structure and water flows make them have mixed-induced speleogenesis.
The removal of lead by natural zeolite
Authors: Budianta Wawan , Ardiana Adinda , Andriyani Norma Dian
Published: October 2020

This study aimed to evaluate the ability of natural zeolite samples obtained from Gunungkidul, Yogyakarta, Indonesia in the removal of lead (Pb) in solutions. This study included mineralogical characterization as well as a batch test in the laboratory with parameters including grain size, the mass of natural zeolite sample, pH, and initial concentration of the solution. The results of mineralogical characterization showed that the natural zeolite sample have varied constituent on mineral components and relatively have high cation exchange capacity (CEC). The results of the batch test showed that the adsorption behavior depends on the mass of the zeolite sample which the increasing of the sample mass will increase the adsorption capacity. The results of the following batch testing showed that the variations in grain size had a limited effect on the adsorption capacity and the effect of the pH of the solution being a significant parameter. The results of the following batch test also showed that the increasing initial concentration of Pb solution caused a decrease in adsorption capacity. In general, natural zeolite samples in the study area have sufficient adsorption capacity as adsorbent material for Pb solution.
Methane gas hydrates influence on sudden coal and gas outbursts during underground mining of coal deposits
Authors: Bondarenko Volodymyr , Svietkina Olena , Lysenko Roman , Liu Baochang
Published: October 2020

The mechanism of gas hydrates formation in coal seams is studied in the paper, as well as their involvement is hypothesized in the sudden outbursts of coal and gas during underground mining of coal deposits. It has been substantiated and proved that one of the real reasons for subsequent outbursts is the formation of gas hydrates in coal as a type of secondary gas hydrate deposits. It has been also substantiated that, as a result of coal metamorphism, a large amount of gaseous hydrocarbons, mainly methane, is formed in the seam, which under certain thermobaric conditions leads to the gas hydrates formation. It has been experimentally proved that the mechanism of such inclusions formation between gas hydrate and coal is a result of strong chemisorption, which, when disturbing thermobaric conditions, leads to gas-dynamic activity of coal seams. It has been revealed that during the dissociation of gas hydrates, obtained in a medium of activated coals, twice as much gaseous methane is released. The research analysis indicates that the formation of natural gas solid solutions in coal pores under certain thermodynamic conditions and the natural humidity, characteristic of coal seams, is one of the causes of sudden coal and gas outbursts. The gas hydrates dissociation influences on the gas-dynamic activity of a coal seam and the formation of an outburst hazardous situation.
Analysis of drill bit speed in bit-rock interaction with the use of numerical simulation methods
Authors: Toshniyozov Lazizjon , Mamatov Muhriddin
Published: October 2020

Bit-rock interaction while drilling wells using numerical simulation methods is analyzed in the article. The effect of the location of the buttons relative to the destruction of the rock, the influence of the structure on the total speed of the drill bit was considered. The total bit velocity was investigated by comparing the results of modeling the operation of the industry bit and the optimized bit. Using methods of numerical modeling allowed creating an atmosphere of the drilling process in a computer environment, where the destruction of rock using a rock cutting tool was analyzed. Due to the pairwise positioning of the buttons in the optimized bit modeled in the ANSYS program, the number of buttons decreased by 13 pieces and the performance of the bit increased significantly. The optimized bit demonstrates more intense penetration into the rock and obvious fragmentation on the rock surface. A drill bit with a pair of buttons rotates more intensively and acts on the cross-sectional area of the rock with values greater than a bit with button of a conventional location. Rising values of the total velocity on the graph signal the dynamic movements of the rock cutting tool.
Effectiveness evaluation for geothermal heat recovery in closed mines of Donbas
Authors: Rudakov Dmytro , Inkin Oleksandr , Dereviahina Nataliia , Sotskov Vadym
Published: October 2020

The study aims to develop a method of effectiveness evaluation for geothermal heat recovery in closed mines of Donbas using relations of heat transfer theory in rocks and fluids. Geothermal heat is proposed to recover using coaxial geothermal probes to be installed in flooded closed mines. As a result of evaluation and ranking, five top promising sites with the highest expected performance indicators among 27 closed mines located in Donbas have been identified. The evaluation method takes into account geological settings, mine condition, and heat exchange parameters of the probe with mine water. The locations of the most promising sites were found to correlate with the areas of higher geothermal flux and the deeper mines. The results obtained can be used in feasibility studies on installation and operation of geothermal probes in closed mines.
Management of the investment activities of the mining industry
Authors: Filipishyna Liliia , Mihai Natalia , Tarasov Ihor , Andriienko Mykola , Arsawan I Wayan Edi
Published: October 2020

The paper studies the main directions of investment activities of mining enterprises within the framework of the industrial development program. The principles of investment activities of mining enterprises have been substantiated, which are correlated with the priorities of socioeconomic development and tools for stimulating investment in the mining industry. At each level of approach to investment activity management of mining enterprises, there is a link between the enterprise and the external environment to assess the investment attractiveness of investment objects and their competitive advantages. Competitive advantages have been revealed, which are largely determined by the direction of investment activities of mining enterprises as a result of direct investment, on the one hand, and the role of investment activities in increasing the competitive advantages of the mining industry. Taking into account the risk-forming factors of the macro – and micro environment of the mining industry, the foundations of the investment processes development have been substantiated when choosing financing instruments, which provides the optimal ratio of return and investment risk for all stakeholders.
Modeling of a braking process of a mine diesel locomotive in terms of different rail track conditions
Authors: Taran Ihor , Bondarenko Anatolii , Novytskyi Oleksii , Zhanbirov Zhemazhan , Klymenko Iryna
Published: October 2020

The paper considers braking process of mine diesel locomotive with hydrostatic mechanical transmission (HSMT) operating according to “input differential” scheme. Braking process is modeled in terms of kinematic motor disconnection from wheels under maximum possible braking moments on wheels.Showing up and systematizing of basic regularities concerning the distribution of power flows within closed transmission contour in the process of braking have been implemented with the help of software support developed by means of MatLab/Simulink. The simulation results of braking due to the hydrostatic transmission and the braking system during the movement of a diesel locomotive in the transport and tractive ranges are presented in the form of graphical dependences. It has been determined that when a kinematic disconnection of a mechanical branch takes place within the closed loop of HSMT No. 1 by means of a clutch, neither ascent/descent angle nor net tractive effort of mine diesel locomotive effect significantly the distribution of kinematic, power, and energy parameters of the HSMT.
Mining of rich iron ore deposits of complex structure under the conditions of rock pressure development
Authors: Pysmennyi Serhii , Fedko Mykhailo , Shvaher Nataliia , Chukharev Serhii
Published: October 2020

The purpose of research is to increase the ore mass extraction ratio when mining rich iron ores by changing the shape of the stope chamber, as well as to substantiate its stable parameters under the conditions of the rock pressure manifestation. Used in mines existing methodologies for determining the structural elements of mining system are based on calculated equivalent spans of outcropping the stope chambers, which have a rectangular or tent shape. For the first time using the ANSYS software package, it has been determined that the formation of a compensation chamber of quasi-parabolic shape can significantly reduce the stresses concentration around the stope block. Thus, the formation of a stope chamber of a quasi-parabolic shape makes it possible to reduce vertical stresses as compared to horizontal ones without increasing horizontal pressure. When mining the extraction block, it is proposed to form the stope chamber of a quasi-parabolic shape with geometric parameters that directly depend on the parameters of the deposit, the depth of mining, and the direction of main stresses action. Dependences have been determined of the stresses value on the depth of mining and the physical properties of rocks, as well as on the length along the strike of the ore deposit. Thus, depending on the mining depth and length along the strike, rock pressure on the stope chamber of a quasi-parabolic shape decreases under non-uniform loading. The formation of a stope chamber of a quasi-parabolic shape will increase by 1.2 – 1.5 times the volume of pure ore that is recovered from the block.
Investigation and optimization of main materials consumption when mining iron ores at deep levels of the Underground Mine Group of the PJSC “ArcelorMittal Kryvyi Rih”
Authors: Stupnik Mykola , Kalinichenko Vsevolod , Kalinichenko Olena , Yakovlieva Sofiia
Published: October 2020

The work considers conditions of deep levels of the Underground Mine Group for underground ore mining (as underground mines) of the Mining Department of the PJSC “ArcelorMittal Kryvyi Rih” (the PJSC “ArcelorMittal Kryvyi Rih”). The research aims to improve indicators of mined ore mass extraction when mining rich iron ores through studying and optimizing consumption of explosives, enhancing mining technology to provide fulfilment of the underground iron ore mining program. During the research, there are analyzed mining geological and technical conditions of the deposit mining as well as current technologies of iron ore mining at the Underground Mine Group of the PJSC “ArcelorMittal Kryvyi Rih”. The work analyzes the achieved indices and consumption of explosives for drilling and blasting at the Underground Mine Group. The mining geological and technical conditions of the deposit mining as well as current technologies of mining, parameters of preparatory operations, the nomenclature and qualitative characteristics of many types of explosives are determined to have changed. This complicates planning consumption of explosives and making their estimates for work sites. However, this is a reason for selecting highly efficient technology and machinery in deteriorating mining and geological conditions of operating at over 1200 m depths. The work determines dependencies of a stress value on a mining depth and physical properties of rocks, as well as parameters of drilling and blasting operations considering the stress-strain state of the massif under high rock pressure at deep levels of the Mining Group of the PJSC “ArcelorMittal Kryvyi Rih”.
Substantiation of averaging the content of mined ores with account of their readiness for mining
Authors: Kalybekov Tursyn , Rysbekov Kanay , Nаuryzbayeva Dilda , Toktarov Ayan , Zhakypbek Yryszhan
Published: October 2020

Paper demonstrates the importance of substantiating the reserves volumes ready for mining in extraction units, in accordance with the mine output capacity, averaging mode and reducing the variation in the mined product quality. Rational methods of planning mining operations based on innovative technological solutions to achieve high-quality ore mass uniformity in terms of mineralogical composition are presented. Optimization of mineral extraction scheduling is possible with a comprehensive analysis of the existing situation and determining a well-founded method for mining operations. Averaging the mined ores content by two components requires a change in their volume planned for separate panels. Based on critical analysis and personal analytical research, a new method has been developed for averaging the mineral raw materials content. The method of ore content bottom-hole averaging in underground mining is substantiated, taking into account the output distribution over extraction units and obtaining a uniform quality of the extracted raw materials. The proposed method of averaging the minerals quality differs from the existing ones by the optimal ore volumes distribution in accordance with their content directly in the mined-out faces of the panels during the period of the field exploitation by underground method.
A versatile set-up to study plasma/microwave sources for liquid fuel ignition
Authors: Fragge Beatrice , Sokoloff Jérôme , Rouzaud Olivier , Pascal Olivier , Orain Mikael
Published: October 2020

Motivated by the high demand for an alternative, more reliable, high energy ignition source to facilitate the re-ignition of lean-burn combustion chambers which are necessary to reduce pollutant emissions, a new set-up has been designed to study plasma/microwave sources. The use of a waveguide-based resonant cavity leads to very low power plasma ignition. An example in this paper shows that a plasma at atmospheric pressure can be maintained with less than 2 W input power. Such a performance is possible using the large variety of possible adjustments (resonance frequency, different kind of initiators, etc.) that this versatile set-up offers. To illustrate the wide range of possible studies, another example is given and discussed : minimum ignition energy for an ethanol droplet stream with aluminum and stainless steel initiators. The results show that the initiator material and its surface quality have an influence on the minimum ignition energy, especially for large gaps. Depending on the gap size we can get down to under 10 W entering the cavity to ignite the droplet stream.
Anterior Cruciate Ligament Reconstructed Female Athletes Exhibit Relative Muscle Dysfunction After Return to Sport
Authors: Raymond-Pope Christiana J. , Dengel Donald R. , Fitzgerald John S. , Nelson Bradley J. , Bosch Tyler A.
Published: October 2020

We sought to examine the relationship between upper-leg compartmental lean mass, muscle-specific strength, and explosive strength following anterior cruciate ligament reconstruction. Twleve adolescent female athletes with prior anterior cruciate ligament reconstruction were individually-matched by age (16.4±0.9 vs. 16.4±1.0 yrs.), body mass index (23.2±2.1 vs. 23.2±2.7 kg/m2), and sport to 12 female athlete controls. One total-body and 2 lateral-leg dual X-ray absorptiometry scans measured total/segmental body composition. Isokinetic dynamometry measured knee extensor/flexor peak torque. Squat jumps on force platforms measured bilateral peak vertical ground reaction force. Paired t-tests assessed lean mass, peak torque, and force between previously-injured athletes’ legs and between previously-injured and control athletes’ legs. Previously-injured athletes’ involved vs. non-involved leg demonstrated lower total (7.13±0.75 vs. 7.43±0.99 kg; p<0.01) and anterior (1.49±0.27 vs. 1.61±0.23 kg; p<0.01) and posterior (1.90±0.19 vs. 2.02±0.21 kg; p=0.04) upper-leg lean mass. Involved leg peak torque (1.36±0.31; 1.06±0.27; 0.97±0.19 Nm/kg) was lower vs. non-involved leg (1.71±0.36; 1.24±0.33; 1.04±0.15 Nm/kg; p<0.01−0.02) for extension at 60 and 120°/sec and flexion at 60°/sec and vs. controls’ ‘matched’ leg (1.77±0.40 Nm/kg; p=0.01) for extension at 60°/sec. Involved leg force (296±45N) was lower vs. non-involved leg (375±55N; p<0.01) and vs. controls’ ‘matched’ leg (372±88N; p=0.02). One-year post-anterior cruciate ligament reconstruction, adolescent female athletes’ involved leg demonstrated relative muscle dysfunction.
Synthesis of Selenopyrano[2,3-c]pyrazol-4(1H)-ones and Their C–H Activation
Authors: Jalani Hitesh B. , Jeong Jin-Hyun , Choi In-Hui
Published: October 2020

We disclose the synthesis of selenopyrano[2,3-c]pyrazol-4(1H)-ones and their aryl derivatives for the first time by using selenopyran ring formation via an in situ-generated selenide that reacts directly with α-halo-β-ynone-bearing substituted pyrazoles to provide the corresponding selenopyrano[2,3-c]pyrazol-4(1H)-ones. Subsequent direct C–H arylation of the latter compounds effected by palladium-catalyzed Heck reactions permits the incorporation of arene substituents onto the selenopyrano[2,3-c]pyrazol-4(1H)-ones scaffolds with moderate to good yields, and might be useful for biological screenings.
A simple experimental method for measuring the thermal sensitivity of single-mode fibers
Authors: Bondza Saskia , Bengtsson Alexander , Horvath Sebastian P. , Walther Andreas , Kröll Stefan , Rippe Lars
Published: October 2020

We present a simple technique to experimentally determine the optical-path length change with temperature for optical single-mode fibers. Standard single-mode fibers act as natural low-finesse cavities, with the Fresnel reflection of the straight cleaved surfaces being ∼3%, for the laser light coupled to them. By measuring the intensity variations due to interference of light reflected from the fiber front and end surfaces, while ramping the ambient temperature, the thermal sensitivity of the optical-path length of the fiber can be derived. Light was generated by a narrow linewidth, low drift laser. With our fairly short test fibers, we found that it was possible to reach a relative precision of the temperature sensitivity, compared to a reference fiber, on the 0.4%–2% scale and an absolute precision of 2%–5%, with the potential to improve both by an order of magnitude. The results for single-acrylate, dual-acrylate, and copper- and aluminum-coated fibers are presented. Values are compared with analytic models and results from a finite element method simulation. With the aid of these measurements, a simple fiber-interferometer, which is insensitive to thermal drifts, could be constructed.
Spectral triangles of non-selfadjoint Hill and Dirac operators
Authors: Djakov P. B. , Mityagin B. S.
Published: October 2020

This is a survey of results from the last 10 to 12 years about the structure of the spectra of Hill–Schrödinger and Dirac operators. Let

be a Hill operator or a one-dimensional Dirac operator on the interval

. If

is considered with Dirichlet, periodic, or antiperiodic boundary conditions, then the corresponding spectra are discrete and, for sufficiently large

, close to

in the Hill case or close to

in the Dirac case (

). There is one Dirichlet eigenvalue

and two periodic (if

is even) or antiperiodic (if

is odd) eigenvalues

and

(counted with multiplicity). Asymptotic estimates are given for the spectral gaps

and the deviations

in terms of the Fourier coefficients of the potentials. Moreover, precise asymptotic expressions for

and

are found for special potentials that are trigonometric polynomials.

Bibliography: 45 titles.
Experimental evidence for silica-enriched Earth’s lower mantle with ferrous iron dominant bridgmanite
Authors: Mashino Izumi , Murakami Motohiko , Miyajima Nobuyoshi , Petitgirard Sylvain
Published: October 2020

Significance

Iron-bearing bridgmanite is the most abundant mineral in the Earth’s interior. We overcome the experimental challenge of measuring iron-bearing materials by using Brillouin scattering techniques optimized for extreme pressure conditions in combination of diamond-anvil cell. By using such techniques, results of acoustic wave velocities in the pressure range of the entire mantle are reported here. Based on our results, we show that the greater part of the lower mantle is Fe
2+
-rich because the gradient of our model gives excellent fit to that of Preliminary Reference Earth Model for almost all the pressure range of the lower mantle with an Fe
3+
/ΣFe of 0.2. Our lower-mantle model also shows a distinctive Si-enriched composition with Mg/Si of 1.14 relative to the upper mantle.
Visualization of the HIV-1 Env glycan shield across scales
Authors: Berndsen Zachary T. , Chakraborty Srirupa , Wang Xiaoning , Cottrell Christopher A. , Torres Jonathan L. , Diedrich Jolene K. , López Cesar A. , Yates John R. , van Gils Marit J. , Paulson James C. , Gnanakaran Sandrasegaram , Ward Andrew B.
Published: October 2020

Significance

The HIV-1 Env “glycan shield” masks the surface of the protein from immune recognition, yet intrinsic heterogeneity defies a typical structure–function description. Using an integrated approach of cryo-EM, computational modeling, and mass spectrometry, we visualized the glycan shield structure in a new light. Our approach facilitated development of cryo-EM analysis methods and allowed for validation of models against experiment. Comparison of Env expressed in different cell lines revealed how subtle differences in composition impact glycan shield structure and affect the accessibility of epitopes on the surface, providing insights for vaccine design. Finally, time-resolved cryo-EM experiments uncovered how highly connected glycan clusters help stabilize the prefusion trimer, suggesting the glycan shield may function beyond immune evasion.
A symmetry-derived mechanism for atomic resolution imaging
Authors: Krajnak Matus , Etheridge Joanne
Published: October 2020

Significance

An “image” is a representation of an object, providing information about its form and structure. In many imaging systems, image contrast arises when the object alters the energy, phase, and/or amplitude of the probing radiation. Here, we introduce an image contrast that arises when the object alters the
symmetry
of the probing radiation. We demonstrate this in scanning transmission electron microscopy, visualizing changes in object symmetry at the picometer scale. These atomic-resolution symmetry images provide information that can be important in understanding any material where symmetry plays a significant role, including symmetry-breaking events, such as point and planar structural defects, strain, and local electric and magnetic fields.
A release from developmental bias accelerates morphological diversification in butterfly eyespots
Authors: Brattström Oskar , Aduse-Poku Kwaku , van Bergen Erik , French Vernon , Brakefield Paul M.
Published: October 2020

Significance

The concept of developmental bias argues that developmental processes can influence the direction of evolutionary change in morphology. We survey wing patterns across Mycalesina butterflies, focusing on a pattern element called eyespots. The relative color composition of these spots has been considered to be a prime example of developmental bias but had not been studied extensively in a phylogenetic context. We show that developmental bias is limiting the evolutionary independence of eyespot color composition but not size in most groups of Mycalesina butterflies. However, a release from developmental bias has enabled the Malagasy genus
Heteropsis
to evolve more diverse wing patterns. Using laboratory experiments, we investigate the developmental changes underlying this release.
Mcl-1 and Bok transmembrane domains: Unexpected players in the modulation of apoptosis
Authors: Lucendo Estefanía , Sancho Mónica , Lolicato Fabio , Javanainen Matti , Kulig Waldemar , Leiva Diego , Duart Gerard , Andreu-Fernández Vicente , Mingarro Ismael , Orzáez Mar
Published: October 2020

Significance

Key members of the Bcl-2 family of proteins that control cell death possess a carboxy-terminal transmembrane segment that contributes to subcellular localization and modulates apoptotic functions. The role of Mcl-1 and specially Bok proteins remains elusive. We reveal that the coexpression of Mcl-1 and Bok TMDs produces an increase in the number of ER mitochondrial-associated membranes (MAMs). Furthermore, our findings provide mechanistic insight into the interaction between Mcl-1 and Bok transmembrane domains that can be envisioned as a target for therapeutic intervention.
Reversible autoinhibitory regulation of
Escherichia coli
metallopeptidase BepA for selective β-barrel protein degradation
Authors: Daimon Yasushi , Narita Shin-ichiro , Miyazaki Ryoji , Hizukuri Yohei , Mori Hiroyuki , Tanaka Yoshiki , Tsukazaki Tomoya , Akiyama Yoshinori
Published: October 2020

Significance

The outer membrane (OM) of gram-negative bacteria functions as a permeability barrier against xenobiotics and is essential for their viability. The periplasmic zinc-metallopeptidase BepA maintains the integrity of the OM by either promoting the assembly of LptD, a β-barrel component of the lipopolysaccharide translocon in the OM, or degrading it when its correct assembly is compromised. How BepA uses its dual functions properly and exerts its protease activity specifically against LptD to be degraded has been unknown. This study shows that the activity of BepA is regulated by reversible autoinhibition mediated by His-246 that acts as the fourth zinc ligand. These findings provide insights into the regulation of metallopeptidases and the quality control of bacterial outer-membrane proteins.
Origin of exponential growth in nonlinear reaction networks
Authors: Lin Wei-Hsiang , Kussell Edo , Young Lai-Sang , Jacobs-Wagner Christine
Published: October 2020

Significance

Natural systems (e.g., cells and ecosystems) generally consist of reaction networks (e.g., metabolic networks or food webs) with nonlinear flux functions (e.g., Michaelis–Menten kinetics and density-dependent selection). Despite their complex nonlinearities, these systems often exhibit simple exponential growth in the long term. How exponential growth emerges from nonlinear networks remains elusive. Our work demonstrates mathematically how two principles, multivariate scalability of flux functions and ergodicity of the rescaled system, guarantee a well-defined growth rate. By connecting ergodic theory, a powerful branch of mathematics, to the study of growth in biology, our theoretical framework can recapitulate various growth modalities (from balanced growth to periodic, quasi-periodic, or even chaotic behaviors), greatly expanding the types of growing systems that can be studied.
Land-use intensity alters networks between biodiversity, ecosystem functions, and services
Authors: Felipe-Lucia María R. , Soliveres Santiago , Penone Caterina , Fischer Markus , Ammer Christian , Boch Steffen , Boeddinghaus Runa S. , Bonkowski Michael , Buscot François , Fiore-Donno Anna Maria , Frank Kevin , Goldmann Kezia , Gossner Martin M. , Hölzel Norbert , Jochum Malte , Kandeler Ellen , Klaus Valentin H. , Kleinebecker Till , Leimer Sophia , Manning Peter , Oelmann Yvonne , Saiz Hugo , Schall Peter , Schloter Michael , Schöning Ingo , Schrumpf Marion , Solly Emily F. , Stempfhuber Barbara , Weisser Wolfgang W. , Wilcke Wolfgang , Wubet Tesfaye , Allan Eric
Published: October 2020

Significance

Ecosystem services derive from ecosystem functions and rely on complex interactions among a diversity of organisms. By understanding the relationships between biodiversity, ecosystem functions, and the services humans receive from nature, we can anticipate how changes in land use will affect ecosystems and human wellbeing. We show that increasing land-use intensity homogenizes the synergies between three organizational levels of the ecosystem, namely, biodiversity, ecosystem functions, and services. Increasing land-use intensity changes keystone components, which are important for the functioning of the ecosystem, and alters the synergies and trade-offs between biodiversity, ecosystem functions, and services. Our approach provides a comprehensive view of ecosystem functioning and can identify the key ecosystem attributes to monitor in order to prevent critical shifts in ecosystems.
Lysosomal cathepsin creates chimeric epitopes for diabetogenic CD4 T cells via transpeptidation
Authors: Reed Brendan , Crawford Frances , Hill Ryan C. , Jin Niyun , White Janice , Krovi S. Harsha , Marrack Philippa , Hansen Kirk , Kappler John W.
Published: October 2020

The identification of the peptide epitopes presented by major histocompatibility complex class II (MHCII) molecules that drive the CD4 T cell component of autoimmune diseases has presented a formidable challenge over several decades. In type 1 diabetes (T1D), recent insight into this problem has come from the realization that several of the important epitopes are not directly processed from a protein source, but rather pieced together by fusion of different peptide fragments of secretory granule proteins to create new chimeric epitopes. We have proposed that this fusion is performed by a reverse proteolysis reaction called transpeptidation, occurring during the catabolic turnover of pancreatic proteins when secretory granules fuse with lysosomes (crinophagy). Here, we demonstrate several highly antigenic chimeric epitopes for diabetogenic CD4 T cells that are produced by digestion of the appropriate inactive fragments of the granule proteins with the lysosomal protease cathepsin L (Cat-L). This pathway has implications for how self-tolerance can be broken peripherally in T1D and other autoimmune diseases.
Charles E. Egwuagu: Going with the flow
Authors: Houston Stephanie
Published: October 2020

Charles E. Egwuagu is an epidemiologist/immunologist and chief of the Molecular Immunology Section at the National Eye Institute, National Institutes of Health, Bethesda, MD. His laboratory is focused on understanding the role played by lymphocytes in autoimmune diseases of the central nervous system. I chatted with Charles about his career so far.
Causal concept for black hole shadows
Authors: Siino Masaru
Published: October 2020

Causal concept for the general black hole shadow is investigated, instead of the photon sphere. We define several ‘wandering null geodesics’ as complete null geodesics accompanied by repetitive conjugate points, which would correspond to null geodesics on the photon sphere in Schwarzschild spacetime. We also define a ‘wandering set’, that is, a set of totally wandering null geodesics as a counterpart of the photon sphere, and moreover, a truncated wandering null geodesic to symbolically discuss its formation. Then we examine the existence of a wandering null geodesic in general black hole spacetimes mainly in terms of Weyl focusing. We will see the essence of the black hole shadow is not the stationary cycling of the photon orbits which is the concept only available in a stationary spacetime, but their accumulation. A wandering null geodesic implies that this accumulation will be occur somewhere in an asymptotically flat spacetime.
Development of static correlation functional using electron distribution on the energy coordinate
Authors: Takahashi Hideaki
Published: October 2020

A static correlation error (SCE) inevitably emerges when the dissociation of a covalent bond is described with a conventional density-functional theory (DFT) for electrons. The SCE gives rise to a serious overshoot in the potential energy (PE) at the dissociation limit even in the simplest molecules. The error is attributed to the basic framework of the approximate functional for the exchange correlation energy E
xc which refers only to local properties at coordinate
r
, namely, the electron density n(
r
) and its derivatives. To solve the problem we developed a functional

E

x
c

e

that uses the energy electron distribution n
e(ϵ) as a fundamental variable in DFT. n
e(ϵ) is obtained by projecting the density n(
r
) onto an energy coordinate ϵ defined by the external potential of interest. The functional was applied to the dissociations of single, double, and triple bonds in small molecules, showing reasonable agreement with the results given by a high-level molecular orbitals theory. We also applied the functional to the computation of the energy change associated with spin depolarization and symmetrization in a carbon atom, which made an improvement over the conventional functional. This work opens the way to develop a tougher functional that necessitates nonlocal properties of electrons, such as a kinetic energy functional.
Streamer propagation and pressure waves produced by a nanosecond pulsed surface sliding discharge: effect of the high-voltage electrode shape
Authors: Moreau E , Bayoda K , Benard N
Published: October 2020

This paper aims at better understanding nanosecond sliding discharges based on a three-electrode geometry and at studying the effect of the shape of the pulsed high-voltage electrode on their electrical, optical and mechanical properties. Three different electrode shapes are considered: a typical planar electrode with a straight edge, a planar electrode with a sawtooth edge, and a wire electrode. First, we verified that the sliding discharge starts to appear when the potential difference between both air-exposed electrodes exceeds about 25 kV, corresponding to a mean electric strength (potential difference divided by the gap) a little bit higher than 6 kV cm−1, but this value differs slightly depending on the shape of the electrode. Secondly, we highlighted that the current with the wire-based discharge is slightly higher compared to the two others because the streamers are more numerous and they are more uniformly distributed along the wire. Moreover, whatever the electrode shape, intensified charge-coupled device visualizations showed that many streamers initiate from the pulsed high-voltage electrode edge and propagate on the dielectric surface toward the DC voltage electrode at a mean velocity of about 1 mm ns−1. However, the streamer trajectory depends strongly on the electrode shape. Visualizations of the pressure waves induced by the different plasma actuators have been realized with a shadowgraph system. In the presence of a sliding discharge, every streamer is at the origin of three different pressure waves. The first hemispherical pressure wave results from streamer ignition at the edge of the pulsed high-voltage electrode, the head of the streamer acting as a point heat source. The second hemispherical pressure wave is due to the corona-type discharge that ignites from the negative DC high-voltage electrode when the streamer head gets closer. Finally, the third wave is a semi-cylindrical wave as each streamer acts as a line source of heat. To conclude, pressure measurements highlighted that the peak value of the pressure is nearly constant along the spanwise direction of the wire electrode as it presents high fluctuations with the sawtooth electrode, the maximum pressure being measured above the tips, where streamers are localized.
Atomistic investigation of mechanical properties of metallic glass nanocomposites
Authors: Zhou Xiaoling , Wang Longqi , Chen Changqing
Published: October 2020

In this paper, tensile deformation of metallic glass (MG) nanocomposites which consist of cellular MG matrix and columnar grains are studied by the molecular dynamic simulations. The size effects of the ligament thickness and the grain size on the yield strength and plasticity are elucidated. It is found that the ratio of the grain size to the ligament thickness (d/s) has a great influence on the plastic deformation. Two typical deformation mechanisms are further investigated. In the composite models with large d/s, grain boundaries motion and voids formation are the main mechanisms. When d/s decreases to 6, the grains can not only promote multiple shear bands formation but also impede the main shear band propagation. As a result, large plastic plateau appears in the stress–strain curve. These results are helpful to optimize the mechanical properties of MG composites.
Carbon nanotubes assembled on porous TiO2 matrix doped with Co3O4 as sulfur host for lithium–sulfur batteries
Authors: Qiu Weilong , Li Jing , Zhang Yongguang , Kalimuldina Gulnur , Bakenov Zhumabay
Published: October 2020

Advanced design and fabrication of high performance sulfur cathodes with improved conductivity and chemical adsorption towards lithium polysulfides (LiPS) are crucial for further development of Li–S batteries. Hence, we designed a TiO2/Co3O4-CNTs composite derived from Ti-MOF (MIL-125) as the host matrix for sulfur cathode. The polar nature of metal oxides (TiO2, Co3O4) creates the adsorptive sites in the composite and leads to an efficient chemical capture of LiPS. The CNTs ensure the contact between S/Li2S and the host material with high conductivity, enhanced charge transfer and fast electrochemical kinetics. At the same time, the CNTs strengthen the stability of the electrode material. Consequently, the as-prepared TiO2/Co3O4-CNTs composite showed excellent electrochemical performance. The cell with S–TiO2/Co3O4-CNTs delivers an initial specific capacity of 1270 mAh g–1 at 0.2 C and high rate performance with a capacity of 603 mAh g–1 at 3 C.
Plasma flux expansion control on the DIII-D tokamak
Authors: Anand H , Humphreys D , Eldon D , Leonard A , Hyatt A , Sammuli B , Welander A
Published: October 2020

A new controller has been developed with help of the flexible divertor poloidal-field coil set of the DIII-D tokamak, to aid in the precise control of the flux expansion in the scrape-off layer. The single-input multiple-output architecture ensures flexibility through a complementary set of orthogonal actuator direction to guarantee minimum effect on existing controlled variables, e.g. radial and vertical position control of the X-point. A non-linear free-boundary simulation code (GSevolve) is used for simulating the closed-loop response and for verifying the implementation of the control algorithm on the DIII-D plasma control system. First results of the experimental commissioning of the new controller during 2020 DIII-D campaign are also presented.
Effects of AlInN graded polarization-dependent doped top cladding on the performance of deep ultra-violet laser diode emitting at ∼271 nm wavelength
Authors: Paliwal Avinash , Singh Kuldip , Mathew Manish
Published: October 2020

This work presents the theoretical study on the polarization induced p-type doping of undoped-AlInN graded cladding layers for the deep ultra-violet laser diode (LD) emitting at around 271 nm wavelength. The reference LD consists of 320 nm of linearly graded undoped AlN-Al0.7Ga0.3N layer, while in our LD the graded undoped AlN-Al0.7Ga0.3N layer is replaced by the undoped AlN-Al
x
In(1−x)N composition graded layers with different x mole fraction from 0.88 to 0.92. The static device resistance for reference LD is ∼28.6 Ω which is reduced to ∼18.38 Ω for AlN-Al0.12In0.88N graded layer at 500 mA. The device resistance has been reduced dramatically by ∼10.2 Ω. The reduction in resistance is attributed to the increased polarization grading in AlN-Al0.12In0.88N. The large polarization grading leads to large hole carrier induction in the layer which increases the p-type conductivity of the undoped AlN-Al0.12In0.88N graded layer. Threshold current for reference LD is 393 mA which has been reduced to 384 mA for AlN-Al0.12In0.88N. The electron leakage has reduced from 0.9 kA cm−2 to 0.11 kA cm−2 at ∼30 kA cm−2 injected current density, whereas the hole transportation has improved from 29.23 kA cm−2 to ∼30 kA cm−2 at ∼30 kA cm−2 injected current density.