bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent advances in VO2-based thermochromic composites for smart windows
Authors: Xu Fang , Cao Xun , Luo Hongjie , Jin Ping
Published: January 2018

Vanadium dioxide (VO2) is a well-known thermochromic material since it exhibits a notable optical variation in the near-infrared region from transmitting to reflecting upon the semiconductor-to-metal phase transition (SMT).
Investigating low-valent compositions in the Na3V2O2x(PO4)2F3−2x family: structural transitions and their consequences
Authors: Palomares V. , Blas M. , Setien S. , Lezama L. , Pramudita James C. , Quadir Zakaria , Sharma Neeraj
Published: January 2018

A member of the family of compounds with a formula Na3V2O2x(PO4)2F3−2x is synthesized by carbothermal reduction and 2 consecutive hydrothermal processes.
Reduced‐order model of cascaded doubly fed induction generator for aircraft starter/generator
Authors: Sadeghi Ramtin , Madani Seyed M. , Agha‐kashkooli Mohammad‐Reza , Ataei Mohammad
Published: January 2018

Here, a reduced‐order model for stand‐alone cascaded doubly fed induction generator (CDFG) is presented for aircraft application, which is capable of operating in both starting and generating modes. This generator has lower maintenance cost and higher reliability, in comparison with traditional variable speed constant frequency system, based on a doubly fed induction generator (DFIG). These features make the CDFG appropriate for embedded aircraft applications. The main drawback of this generator is its inherent complexity; therefore, its analysis and control design is difficult. This complexity is due to the existence of resistances and voltage sources in the rotor loop of the full‐order model. To overcome this difficulty, this study proposes a reduced‐order model for the CDFG, which is similar to that of the DFIG in the synchronous reference frame. To demonstrate the efficiency of the proposed model, a field‐oriented controller for CDFG is designed based on this model and compared to the full‐order model. The performance and accuracy of the proposed model is validated through simulation and experimental results subject to balanced and unbalanced load change, and rotor speed variations test scenarios.
Spatially adaptive total variation deblurring with split Bregman technique
Authors: Dodangeh Mahdi , Figueiredo Isabel N. , Gonçalves Gil
Published: January 2018

In this study, the authors describe a modified non‐blind and blind deconvolution model by introducing a regularisation parameter that incorporates the spatial image information. Indeed, they have used a weighted total variation term, where the weight is a spatially adaptive parameter based on the image gradient. The proposed models are solved by the split Bregman method. To handle adequately the discrete convolution transform in a moderate time, fast Fourier transform is used. Tests are conducted on several images, and for assessing the results, they define appropriate weighted versions of two standard image quality metrics. These new weighted metrics clearly highlight the advantage of the spatially adaptive approach.
Properties of multisection transdirectional coupled‐line couplers
Authors: Li Eric S. , Kang Chen‐Jer
Published: January 2018

This study is presented to explore the properties of multisection transdirectional coupled‐line couplers (TRD CLCs) developed for bandwidth enhancement. Unlike conventional multisection contradirectional coupled‐line couplers (CTD CLCs) comprising only CTD CLCs, the proposed multisection TRD CLCs may require the combination of transdirectional and CTD CLCs for some higher‐order designs. The designs feature a central TRD CLC. A symmetrical structure with respect to the central coupler is proposed to meet the port assignments of transdirectional couplers with broadband performance on the magnitude difference as well as the phase difference of 90° between two output ports. It can offer multiple solutions for some multisection designs. Practical examples are presented for 3 dB multisection TRD CLCs with optimum coupling coefficients assigned to individual couplers to achieve maximum bandwidth. Periodic structures are used to implement coupled‐line couplers. Simulation results indicate that the proposed multisection designs meet the required port assignments and offer wider bandwidth compared to a single design of the same coupling. The simulation results of the three‐section design are verified experimentally and good agreement is observed.
Using BIM model for Fire Emergency Evacuation Plan
Authors: Stančík Adam , Macháček Roman , Horák Jiří
Published: January 2018

Is it possible to use building information modelling (BIM) to create a fire emergency evacuation plan in the national condition of the Czech Republic? This article focuses on the advantages and possibilities of using BIM for fire protection.
Development the tool for demand control ventilation systems elements design and their impact to building life-cycle assessment: a review
Authors: Pinka Richard
Published: January 2018

The paper describes possible methodology for DCV – demand control ventilation design process which will lead to solving the most important problems of more accurate ventilation system design, the efficiency: time and costs of design while improving its effectivity (level of design confidence, degree of uncertainty, financial parameters). For this purpose it has been started developing the tool implementing the methodology. Furthermore, it describes steps of testing and validation design process by implementation state-of-the-art algorithms for measuring the occupancy or CO2 detection for DCV system control testing sites and their comparison with computation design results. It describes also the reasons and necessity of decomposition of whole ventilation system to specific elements for the design and assessment procedure.
Use of technical hemp in the construction industry
Authors: Nováková Petra
Published: January 2018

Current requirements for building insulation are constantly increasing, not only in terms of the technical properties of the material used but also in terms of the environmental burden. This article focuses on the use of technical hemp in the building industry, describes individual products, its properties and uses. Part of the article is also the experience of realization and use of the building along with photographs.
Point thermal bridges of insulated pitched roof structures
Authors: Šál Jiří , Štroufová Daniela , Bednářová Petra
Published: January 2018

The current demands on building insulation are continuously increasing. It is understood that the lower the heat transfer coefficient of a particular part of a construction is, the greater the importance of systemic thermal bridges. This article compares the individual systems of insulation of pitched roofs in terms of the heat transfer coefficient. The focus is on the size of the point thermal bridges in rafter thermal insulation systems and determines their impact on increasing the overall heat transfer coefficient. However, it should be noted that point thermal bridges are individually very small and combined only contribute to 2% of the overall heat transfer coefficient of parts of a structure.
Effect of Pressure and Heat Treatments on the Compressive Strength of Reactive Powder Concrete
Authors: Helmi Masdar , Hall Matthew R , Rigby Sean P
Published: January 2018

This paper presents the corresponding compressive strength of RPC with variable pressure combined with heating rate, heating duration, and starting time of heating. The treatments applied were 8 MPa static pressure on fresh RPC prims and heat curing at 240 °C in an oven. The compressive strength test was conducted at 7-d and 28-d. The images of RPC morphology were captured on the surface of a fractured specimen using Scanning Electron Microscopy in Secondary Electron detector mode to describe pore filing mechanism after treatments. The results show that a heating rate at 50 °C/hr resulted in the highest compressive strength about 40 % more than those at 10 or 100 °C/hr. A heating duration of 48 hours led to the maximum compressive strength. Heat curing applied 2 days after casting resulted in the maximum compressive. Heat curing had a signicant effect on the compresssive strength due to the acceleration of both reactions (hydration and pozzolanic) and the degree of transformation from tobermorite to xonotlite. It is concluded that the optimum condition of treatments is both pressure and heat curing at 2-day after casting with a rate of 50 °C/hr for 48 hours.
Diversion Canal to Decrease Flooding (Case Study : Kebon Jati-Kalibata Segment, Ciliwung River Basin)
Authors: Indrawati Dian , Hadihardaja Iwan K. , Bagus Adityawan M. , Pahrizal Syambali F. , Taufik Fajar
Published: January 2018

The flood in Jakarta has become a national concern in Indonesia. It is a haunting disaster, with a high probability to happen when heavy rainfalls in Jakarta and/or its upstream area. Based on data that was provided by Public Work Agency of DKI Jakarta, there are 78 vulnerable points of inundation in which, most of them are located in Ciliwung river basin, commonly in the meandering segments. One of the worst flooding occurs in Pancoran, at Kebonjati to Kalibata segment in particular. The river discharge in this segment is much higher as compared to the carrying capacity. In addition, this area has a high density of population and thus, difficult to increase the *river capacity* by enlarging the river dimension. In this research, a closed diversion canal is proposed as a solution. The effectiveness of the solution is evaluated using a numerical model, HEC-RAS 4.1. The diversion canal is designed as two culverts, with 2.0 m in diameter. Nevertheless, hydraulic jump may occur at the outlet of the canal due to the relatively steep slope. Therefore, the canal outlet should be designed accordingly. A Hydraulic structure such as a stilling basin can be employed to reduce the energy. The results show that the diversion canal has a good performance in decreasing water level and flood discharge in the study area. The canal has the capacity of 17,72 m3/sec and succesfully decreases the water level by 4.71 – 5.66 m from flood level for 2 – 100 years returned period.
Hydraulic and Groundwater Chemical Parameters of the Aquifer in Malakasari, Bandung
Authors: Ahnaf Jemi S. , Zakaria Zufialdi , Patonah Aton
Published: January 2018

In order to reveal the physical condition of the aquifer, the pumping test using Cooper-Jacob (1946) principle has conducted at well SM5. The observation data of the test then processed to generate various value of hydraulic properties i.e. 3.241x10-4 cm2/sec for transmissivity (T), 8.103x10-6 cm/sec for conductivity (K), 0.05055 for storativity (S), and 3.852x10-3 ft-1 for specific storage (Ss). These data show that the aquifer composed of unconsolidated sedimentary rocks ranged from coarse sand to silt. In addition, also performed the feasibility test of groundwater by using Multimeter which produces chemical parameter data. The chemical parameter of eight well samples have average values of 6.62, 766.25 μs/cm and 376.25 mg/L for pH, electric conductivity (EC), and total dissolved solid (TDS) respectively, while physical observation shows no turbidity and odor.
Analysis of Drinking Water Supply System Improvement Using Fuzzy AHP(Case Study: Subang Local Water Company)
Authors: Budi Prakoso Satrio , Notodarmojo Suprihanto
Published: January 2018

Study of infrastructure is required to improve the drinking water supply system, in order to achieve The Long-Term Plan Targets on Water Supply (RPJMN) 2015-2019 concerning 100% universal and equitable access to drinking water services, in accordance with the purpose of Sustainable Development Goals (SDGs) in 2019. Subang district was selected as a case study of water supply improvement because of the improving development in that area and the population growth rate, influencing the need for drinking water. The purpose study is to determine the problems of drinking water supply system, to analyze alternatives for improving water supply system by performing weighted ranking factors in drinking water supply improvement with AHP method and analyzed by fuzzy logic. The method for water supply system improvement could be performed by looking at influential factors using fuzzy AHP approach to obtain some appropriate alternatives. Technical and operational factors was considered the most influential factor in the improvement of water supply system, followed by management capacity, environment, and financial aspect. Fuzzy method with rule base input approach used in this analysis was influencing the output that became the policy alternative to improve drinking water supply.
Control of pH of retained water in the coastal waste disposal site
Authors: Hem Ramrav , Yamasaki Tomohiro , Sumida Hiroko
Published: January 2018

After landfilling of wastes is completed, the stabilization of landfilled ground requires much time and cost. Therefore, this study aimed to control the pH of retained water in the coastal waste disposal sites during landfilling process, by conducting field surveys and laboratory experiments. In field surveys, we investigated the changes of retained water quality such as pH, salinity, and dissolved oxygen. The results show the pH of retained water has risen to about 10 when the volume of landfilled wastes reached about 25% of landfill capacity. In lowing the pH, we considered a low-cost method by pumping seawater from the adjacent sea into the landfill. The mechanism in this method is that, H+ dissociated from HCO3- in the fresh seawater react with OH- eluted from wastes would result in pH decrease. The laboratory experiments were conducted to verify the effect on pH change by adding fresh seawater to alkalized seawater. As a result, the effect of injecting fresh seawater into alkalized seawater with pH higher than 9 was confirmed. Therefore, this treatment method is suggested to enable the disposal sites to be used promptly after landfilling is completed, by adding fresh seawater to purify the retained water and waste at low cost during landfilling process.
Removal of Copper (II) Ions in Aqueous Solutions by Sorption onto Alkali Activated Fly Ash
Authors: Darmayanti Lita , Notodarmodjo Suprihanto , Damanhuri Enri , Mukti Rino R
Published: January 2018

Fly ash is a particulate material produced from coal combustion power plants with major components are silica, alumina, iron oxide, calcium oxide, magnesium oxide, and carbon which are ideal for metal adsorbents. The potential use of fly ash in the wastewater treatment process is obvious because it can be obtained cheaply in large quatities and it can be used as an adsorbent. However, fly ash still shows lower adsorption capacity unless it is activated. In this study, fly ash activated by NaOH 14 M and KOH 14 M solutions. The batch experiments were carried out to study the sorption of copper ions from aqueous on alkali activated fly ash. The influence of initial concentration and contact time were examined at constant pH and dose of adsorbent. The sorption capacity of copper ions increased with the initial concentration and contact time. The sorption capacities followed the order Na1>Ka1>FA. The adsorption isotherm model exhibited that the Langmuir model is very suitable with copper ions adsorption onto fly ash and alkali activated fly ash. Kinetic study shows that adsorption of copper ions onto FA, Na1, and Ka1 follows the pseudo second-order kinetics.
Efficiency Comparison between Conventional and Modern Port Operation System for Small-Scale Dry Bulk Cargo
Authors: Tiara Aulia , Mukhti Julfikhsan Ahmad
Published: January 2018

Since the launching of Sea Toll Road Program in 2015, the improvement in ports’ operation systems has become Indonesia’s foremost necessity. This improvement commonly leads to equipment modernization, while realistically, modern equipment does not always amount to a productive performance, especially in the context of small-scale ports. Instead, it is prone to creating wasteful capital and maintenance cost as well as making the planning time ineffective. This study compares two options of port operation systems in a small port, which is conventional and technologically-advanced method for dry bulk cargo. It results in thin gaps between each option’s financial assessment variables, which are Internal Rate of Return, Benefit/Cost Ratio and Payback Period, regardless of a stark difference between each option’s equipment cost. This study concludes that with the right approach, the conventional operation system is still the most efficient option compared to its contemporary opposite.
Adaptive Port Planning under Disruptive Trends with focus on the case of The Port of Kuala Tanjung, Indonesia
Authors: Prakoso Andre , Taneja Poonam , Velinga Tiedo
Published: January 2018

As a national strategic project, the Port of Kuala Tanjung draws significant attention at national and international level. Considering the semi-greenfield nature of the port, the diverse set of stakeholders, and the prevailing disruptive trends in the world port business, a robust first-phase port layout is required to kick-start the project and guarantee the overall sustainability of the port development. The objective of this research is to identify any uncertain or disruptive trends, both present and future, and access their implications towards the Port of Kuala Tanjung. Adaptive Port Planning (APP) frameworka will be used as the main methodology in this research. A combination of a literature review and interviews with experts are used to both identify the sources of the uncertain and disruptive trends mentioned above and also to propose adaptation strategies. Based on our qualitative study and interviews with experts, we have concluded that the consolidation of major shipping lines, multi-nationality partnerships, Indonesian regulation, and ship breaking regulations are currently the four most relevant contributions to uncertain and disruptive trends towards the port. To mitigate potential risk and seize opportunity provided by these trends, an industrial port complex concept might become the most promising alternative.
Renewable Energy Potentials along the Bay of Bengal due to Tidal Water Level Variation
Authors: Ahmad Myisha , Hasan G. M. Jahid , Chy H. M. Mohaymen Billah , Mahenoor Gazi Masud Md.
Published: January 2018

The projected increase in energy demand coupled with concerns regarding present reliance on fossil fuel and associated environmental concerns had led to increased interest in exploiting renewable energy sources. Among different renewable energy sources, tidal energy is unique and most suitable because of its predictable nature and capability to ensure supply security. Tide consists of both kinetic and potential energy which can be converted to electricity using well-proven technology. The potential energy of tides - the principal focus of the study, is stored due to rise and fall of the sea level. Head difference created due to tidal variation between basin side and sea side of a barrage stores potential energy which is converted into fast-moving water that rotates turbine and generates electricity. Bangladesh with its long coastline has promising prospects of tidal energy resource development. The study focuses on tidal energy resource exploration and exploitation along several competent locations of the Bengal coastline. Tidal records of flood and ebb tide of these locations are analyzed to calculate the potential energy. Finally, available potential techniques of energy extraction are evaluated for annually generated energy estimation. This study investigates the prospect and utilization of tidal energy concept and reviews the possibilities and opportunities of employment of the technology for sustainable development and climate change mitigation in context of Bangladesh.
Insight look the subsidence impact to infrastructures in Jakarta and Semarang area; Key for adaptation and mitigation
Authors: Andreas Heri , Zainal Abidin Hasanuddin , Pradipta Dhota , Anggreni Sarsito Dina , Gumilar Irwan
Published: January 2018

Land subsidence is not a new phenomenon for Jakarta and Semarang areas. According to some publications, the value of Jakarta’s subsidence may reach 2-4 meter in certain place. Meanwhile, more than 2 meter of subsidence is taking place in northern part of Semarang. Some techniques are being used to derive land subsidence information in these areas such as repeated leveling measurements, GPS surveys, and InSAR measurements. The impact of land subsidence in Jakarta and Semarang could be seen in several ways, such as sea inundation (“Rob” in Javanese), problem on infrastructures, the wider expansion of flooding areas, etc. Cracking on housing, street, “sinking” on the bridges and dyke, problems on drainage are examples of infrastructures problems due to the land subsidence. Huge costs have already been spent to fixing those infrastructures problems both in Jakarta and Semarang. Since mostly liniear pattern of land subsidence are recognized in both area today and probably in the next years to come, in this case the impact especially on infrastructures are probably will getting worse. Insight look the subsidence impact to the infrastuctures in Jakarta and Semarang area would raisen the concern, and become key for adaptation and mitigation.
The progressive realization of human rights to water: the legal basis, policy implications, and monitoring challenge
Authors: Nastiti Anindrya , Prasetiawan Teddy
Published: January 2018

Since 2010, the United Nations General Assembly had explicitly recognized the human right to water and sanitation and obliged States to provide for its progressive realization and entitles everyone to sufficient, safe, acceptable, physically accessible and affordable water for essential personal and domestic uses. This paper scrutinizes the legal basis and the policy implication for human right to water in Indonesia, before and following the annulment of the Water Resource Law 7/2004. This paper considers that one of the greatest challenges is to find an appropriate and internationally-comparable methodology in measuring the progressive realization of human rights to water and sanitation. We also highlight the importance of composite indicators and concludes that single variable indicators are insufficient to capture the range of issues involved in the realization of the human rights to water.
Growth and propagation of self-generated magnetic dipole vortices in collisionless shocks produced by interpenetrating plasmas
Authors: Naseri N. , Bochkarev S. G. , Ruan P. , Bychenkov V. Yu. , Khudik V. , Shvets G.
Published: January 2018

Collisionless shocks generated by colliding relativistic plasmas are studied using particle-in-cell (PIC) simulations. The shock is produced due to the Weibel instabilities that generate current and density filaments and small-scale magnetic fields that are amplified from initial fluctuations. Localized regions of the strong magnetic field in the form of magnetic dipole vortices upstream of the shock are observed in the simulation developed during the nonlinear evolution of the electron and ion filaments. The vortices developing from the merger and subsequent pinching of the small-scale filaments are shown to be moving in the direction opposite to that of the shock. We also found an analytical estimate of the drift velocity of the vortices that are confirmed by the PIC simulations.
Numerical simulation of full-aperture-pair ion optics in a miniature ion thruster
Authors: Nakano M. , Nakamura K. , Nakagawa Y. , Tomita D. , Takao Y. , Koizumi H.
Published: January 2018

The 211-aperture-pair two-grid ion optics of a miniature ion thruster is numerically simulated. Since the plasma in the miniature ion thruster is too inhomogeneous to introduce mirror or translational boundary conditions between apertures, all the apertures of the grid system are considered. The simulation is self-consistent, the ion current profile in the discharge chamber plasma is given by the particle-in-cell with Monte Carlo collision algorithm calculations, and all the ion beams extracted from the full-aperture-pair array were tracked including charge-exchange ions. A scheme for the construction of the full-aperture-pair simulation domain is proposed based on the array of a six-fold hexagonal single-aperture-pair simulation domain, which can be extended to other numbers of aperture pairs. Numerical results on accel impingement current and ion-beam profile are compared to experimental data and shown to be in reasonable agreement. Furthermore, the full-aperture-pair ion-optics model is compared with the single-aperture-pair ion-optics models used in the majority of previous ion-optics simulations, which showed that the full-aperture-pair ion-optics model yielded the most accurate predictions. These results suggest that the ion thruster grid system using an inhomogeneous plasma source can be designed more accurately and effectively using full-aperture-pair ion-optics simulations.
Flow characteristics around a deformable stenosis under pulsatile flow condition
Authors: Choi Woorak , Park Jun Hong , Byeon Hyeokjun , Lee Sang Joon
Published: January 2018

A specific portion of a vulnerable stenosis is deformed periodically under a pulsatile blood flow condition. Detailed analysis of such deformable stenosis is important because stenotic deformation can increase the likelihood of rupture, which may lead to sudden cardiac death or stroke. Various diagnostic indices have been developed for a nondeformable stenosis by using flow characteristics and resultant pressure drop across the stenosis. However, the effects of the stenotic deformation on the flow characteristics remain poorly understood. In this study, the flows around a deformable stenosis model and two different rigid stenosis models were investigated under a pulsatile flow condition. Particle image velocimetry was employed to measure flow structures around the three stenosis models. The deformable stenosis model was deformed to achieve high geometrical slope and height when the flow rate was increased. The deformation of the stenotic shape enhanced jet deflection toward the opposite vessel wall of the stenosis. The jet deflection in the deformable model increased the rate of jet velocity and turbulent kinetic energy (TKE) production as compared with those in the rigid models. The effect of stenotic deformation on the pulsating waveform related with the pressure drop was analyzed using the TKE production rate. The deformable stenosis model exhibited a phase delay of the peak point in the waveform. These results revealed the potential use of pressure drop waveform as a diagnostic index for deformable stenosis.
Filament-induced luminescence and supercontinuum generation in undoped, Yb-doped, and Nd-doped YAG crystals
Authors: Kudarauskas D. , Tamošauskas G. , Vengris M. , Dubietis A.
Published: January 2018

We present a comparative spectral study of filament-induced luminescence and supercontinuum generation in undoped, Yb-doped, and Nd-doped YAG crystals. We show that supercontinuum spectra generated by femtosecond filamentation in undoped and doped YAG crystals are essentially identical in terms of spectral extent. On the other hand, undoped and doped YAG crystals exhibit remarkably different filament-induced luminescence spectra whose qualitative features are independent of the excitation wavelength and provide information on the energy deposition to embedded dopants, impurities, and the crystal lattice itself. Our findings suggest that filament-induced luminescence may serve as a simple and non-destructive tool for spectroscopic studies in various transparent dielectric media.
High operating temperature nBn detector with monolithically integrated microlens
Authors: Soibel Alexander , Keo Sam A. , Fisher Anita , Hill Cory J. , Luong Edward , Ting David Z. , Gunapala Sarath D. , Lubyshev Dmitri , Qiu Yueming , Fastenau Joel M. , Liu Amy W. K.
Published: January 2018

We demonstrate an InAsSb nBn detector monolithically integrated with a microlens fabricated on the back side of the detector. The increase in the optical collection area of the detector resulted in a five-fold enhancement of the responsivity to Rp = 5.5 A/W. The responsivity increases further to Rp = 8.5 A/W with an antireflection coating. These 4.5 μm cut-off wavelength antireflection coated detectors with microlenses exhibited a detectivity of D* (λ) = 2.7 × 1010 cmHz0.5/W at T = 250 K, which can be reached easily with a single-stage thermoelectric cooler or with a passive radiator in the space environment. This represents a 25 K increase in the operating temperature of these devices compared to the uncoated detectors without an integrated microlens.
Quasi-classical approaches to vibronic spectra revisited
Authors: Karsten Sven , Ivanov Sergei D. , Bokarev Sergey I. , Kühn Oliver
Published: January 2018

The framework to approach quasi-classical dynamics in the electronic ground state is well established and is based on the Kubo-transformed time correlation function (TCF), being the most classical-like quantum TCF. Here we discuss whether the choice of the Kubo-transformed TCF as a starting point for simulating vibronic spectra is as unambiguous as it is for vibrational ones. Employing imaginary-time path integral techniques in combination with the interaction representation allowed us to formulate a method for simulating vibronic spectra in the adiabatic regime that takes nuclear quantum effects and dynamics on multiple potential energy surfaces into account. Further, a generalized quantum TCF is proposed that contains many well-established TCFs, including the Kubo one, as particular cases. Importantly, it also provides a framework to construct new quantum TCFs. Applying the developed methodology to the generalized TCF leads to a plethora of simulation protocols, which are based on the well-known TCFs as well as on new ones. Their performance is investigated on 1D anharmonic model systems at finite temperatures. It is shown that the protocols based on the new TCFs may lead to superior results with respect to those based on the common ones. The strategies to find the optimal approach are discussed.
Intrinsic terahertz photoluminescence from semiconductors
Authors: Andrianov A. V. , Zakhar'in A. O.
Published: January 2018

We report on the experimental observation of intrinsic photoluminescence from semiconductors in the terahertz spectral range. The intrinsic terahertz photoluminescence is caused by intraexciton radiative transitions excited during the process of the binding of nonequilibrium electrons and holes into free excitons. The experiments were carried out on high-purity Si crystals at helium temperatures and under interband photoexcitation intensities not exceeding 1 W/cm2.
The nearest neighbor and next nearest neighbor effects on the thermodynamic and kinetic properties of RNA base pair
Authors: Wang Yujie , Wang Zhen , Wang Yanli , Liu Taigang , Zhang Wenbing
Published: January 2018

The thermodynamic and kinetic parameters of an RNA base pair with different nearest and next nearest neighbors were obtained through long-time molecular dynamics simulation of the opening-closing switch process of the base pair near its melting temperature. The results indicate that thermodynamic parameters of GC base pair are dependent on the nearest neighbor base pair, and the next nearest neighbor base pair has little effect, which validated the nearest-neighbor model. The closing and opening rates of the GC base pair also showed nearest neighbor dependences. At certain temperature, the closing and opening rates of the GC pair with nearest neighbor AU is larger than that with the nearest neighbor GC, and the next nearest neighbor plays little role. The free energy landscape of the GC base pair with the nearest neighbor GC is rougher than that with nearest neighbor AU.
A new apparatus for on-site calibration of gamma dose rate monitors
Authors: Zhang Yu , Chen Bo , Zhao Chao , Zhuo Weihai
Published: January 2018

In order to carry out on-site calibrations of environmental gamma dose rate monitors, a new irradiation apparatus was developed in this study. The apparatus mainly consists of a piece of 137Cs source, a set of beam attenuators, and 3 built-in laser rangefinders, and it can be remotely controlled by using a laptop through WiFi network. With an activity of 4.6 × 108 Bq of 137Cs source, the reference air kerma rate could be adjusted from 0.26 μGy h−1 to 140 μGy h−1 by changing the calibration distance from 0.5 m to 5 m and using different beam attenuators (or none), and both the reproducibility and the homogeneity of reference radiation were better than 97%. The overall uncertainty of the calibration was estimated to be 6.5% (k = 2). Both the laboratory and field experiments confirmed that the calibration method met the requirements of ISO 4037-1. As the advantages of portability and simplicity, it is considered that the new irradiation apparatus is applicable to stationary gamma radiation monitors for on-site calibration.
Global models underestimate large decadal declining and rising water storage trends relative to GRACE satellite data
Authors: Scanlon Bridget R. , Zhang Zizhan , Save Himanshu , Sun Alexander Y. , Müller Schmied Hannes , van Beek Ludovicus P. H. , Wiese David N. , Wada Yoshihide , Long Di , Reedy Robert C. , Longuevergne Laurent , Döll Petra , Bierkens Marc F. P.
Published: January 2018

Significance

We increasingly rely on global models to project impacts of humans and climate on water resources. How reliable are these models? While past model intercomparison projects focused on water fluxes, we provide here the first comprehensive comparison of land total water storage trends from seven global models to trends from Gravity Recovery and Climate Experiment (GRACE) satellites, which have been likened to giant weighing scales in the sky. The models underestimate the large decadal (2002–2014) trends in water storage relative to GRACE satellites, both decreasing trends related to human intervention and climate and increasing trends related primarily to climate variations. The poor agreement between models and GRACE underscores the challenges remaining for global models to capture human or climate impacts on global water storage trends.
Shape-directed dynamics of active colloids powered by induced-charge electrophoresis
Authors: Brooks Allan M. , Sabrina Syeda , Bishop Kyle J. M.
Published: January 2018

Significance

Despite recent advances in the ability to “program” the self-assembly of colloidal components, the resulting structures are often static and therefore incapable of performing dynamic functions such as the ability to actuate, heal, replicate, and compute. The realization of colloidal machines that organize in space and time to perform such functions requires new strategies for encoding the dynamic behaviors of colloidal components. Focusing on active colloids powered by induced-charge electrophoresis, we use theory and simulation to show how the shape of a colloidal particle can be rationally tailored to specify complex motions powered by simple energy inputs.
Urban flux measurements reveal a large pool of oxygenated volatile organic compound emissions
Authors: Karl T. , Striednig M. , Graus M. , Hammerle A. , Wohlfahrt G.
Published: January 2018

Significance

The exchange of nonmethane volatile organic compounds (NMVOC) at the surface–atmosphere interface is a fundamental constraint and important boundary condition for atmospheric chemistry and its effects on climate. Anthropogenic emissions are thought to account for about half of the NMVOC flux into the atmosphere of the Northern Hemisphere, yet their budget is considerably uncertain due to the scarcity of appropriate top-down constraints. Here we present direct flux measurements of NMVOCs based on the eddy covariance technique, showing that the contribution of typical urban emission sources is comprised of a surprisingly large portion of oxygenated NMVOC. These results suggest that typical urban NMVOC emission sources could be significantly higher than currently projected in air chemistry and climate models.
Eocene greenhouse climate revealed by coupled clumped isotope-Mg/Ca thermometry
Authors: Evans David , Sagoo Navjit , Renema Willem , Cotton Laura J. , Müller Wolfgang , Todd Jonathan A. , Saraswati Pratul Kumar , Stassen Peter , Ziegler Martin , Pearson Paul N. , Valdes Paul J. , Affek Hagit P.
Published: January 2018

Significance

Reconstructing the degree of warming during geological periods of elevated CO
2
provides a way of testing our understanding of the Earth system and the accuracy of climate models. We present accurate estimates of tropical sea-surface temperatures (SST) and seawater chemistry during the Eocene (56–34 Ma before present, CO
2
>560 ppm). This latter dataset enables us to reinterpret a large amount of existing proxy data. We find that tropical SST are characterized by a modest warming in response to CO
2
. Coupling these data to a conservative estimate of high-latitude warming demonstrates that most climate simulations do not capture the degree of Eocene polar amplification.
Nonfollicular reactivation of bone marrow resident memory CD4 T cells in immune clusters of the bone marrow
Authors: Siracusa Francesco , McGrath Mairi A. , Maschmeyer Patrick , Bardua Markus , Lehmann Katrin , Heinz Gitta , Durek Pawel , Heinrich Frederik F. , Mashreghi Mir-Farzin , Chang Hyun-Dong , Tokoyoda Koji , Radbruch Andreas
Published: January 2018

The bone marrow maintains memory CD4 T cells, which provide memory to systemic antigens. Here we demonstrate that memory CD4 T cells are reactivated by antigen in the bone marrow. In a secondary immune response, antigen-specific T cells of the bone marrow mobilize and aggregate in immune clusters together with MHC class II-expressing cells, mostly B lymphocytes. They proliferate vigorously and express effector cytokines, but they do not develop into follicular T-helper cells. Neither do the B lymphocytes develop into germinal center B cells in the bone marrow. Within 10 days, the immune clusters disappear again. Within 30 days, the expanded antigen-specific memory CD4 T cells return to memory niches and are maintained again individually as resting cells. Thus, in secondary immune responses in the bone marrow T-cell memory is amplified, while in germinal center reactions of secondary lymphoid organs humoral memory is adapted by affinity maturation.
Hsp90 chaperones hemoglobin maturation in erythroid and nonerythroid cells
Authors: Ghosh Arnab , Garee Greer , Sweeny Elizabeth A. , Nakamura Yukio , Stuehr Dennis J.
Published: January 2018

Significance

Maturation of functional adult (α2β2) or fetal (α2γ2) hemoglobin (Hb) tetramers requires that a heme cofactor be incorporated into each globin. During erythropoiesis, Hb-α maturation is aided by the alpha Hb-stabilizing protein (AHSP), but what enables the maturation and heme insertion of the other globins is unknown. We found that chaperone hsp90 stabilizes the immature, heme-free forms of Hb-β and Hb-γ and then drives their heme insertion reactions in an ATP-dependent process. This finding fills an important gap in our understanding of hemoglobin maturation during erythropoiesis and also helps to explain how functional mature Hb can be expressed outside the circulation in nonerythroid cells and tissues that do not express AHSP.
Structural flexibility and protein adaptation to temperature: Molecular dynamics analysis of malate dehydrogenases of marine molluscs
Authors: Dong Yun-wei , Liao Ming-ling , Meng Xian-liang , Somero George N.
Published: January 2018

Orthologous proteins of species adapted to different temperatures exhibit differences in stability and function that are interpreted to reflect adaptive variation in structural “flexibility.” However, quantifying flexibility and comparing flexibility across proteins has remained a challenge. To address this issue, we examined temperature effects on cytosolic malate dehydrogenase (cMDH) orthologs from differently thermally adapted congeners of five genera of marine molluscs whose field body temperatures span a range of ∼60 °C. We describe consistent patterns of convergent evolution in adaptation of function [temperature effects on
K
M
of cofactor (NADH)] and structural stability (rate of heat denaturation of activity). To determine how these differences depend on flexibilities of overall structure and of regions known to be important in binding and catalysis, we performed molecular dynamics simulation (MDS) analyses. MDS analyses revealed a significant negative correlation between adaptation temperature and heat-induced increase of backbone atom movements [root mean square deviation (rmsd) of main-chain atoms]. Root mean square fluctuations (RMSFs) of movement by individual amino acid residues varied across the sequence in a qualitatively similar pattern among orthologs. Regions of sequence involved in ligand binding and catalysis—termed mobile regions 1 and 2 (MR1 and MR2), respectively—showed the largest values for RMSF. Heat-induced changes in RMSF values across the sequence and, importantly, in MR1 and MR2 were greatest in cold-adapted species. MDS methods are shown to provide powerful tools for examining adaptation of enzymes by providing a quantitative index of protein flexibility and identifying sequence regions where adaptive change in flexibility occurs.
Regulation of inflammatory responses by dynamic subcellular localization of RNA-binding protein Arid5a
Authors: Higa Mitsuru , Oka Masahiro , Fujihara Yoshitaka , Masuda Kazuya , Yoneda Yoshihiro , Kishimoto Tadamitsu
Published: January 2018

Significance

Immune cell activation is accompanied by dynamic changes in expression of genes related to inflammation. Concomitantly, immune reactions are tightly controlled to prevent harmful pathologies due to sustained inflammation. Gene expression is controlled at multiple checkpoints. Among these, the post-transcriptional regulation of the balance between Arid5a and Regnase-1 is important for the induction of inflammation. Our findings provide important insight into the role of the regulation of nucleocytoplasmic localization of Arid5a in the development of inflammation through the induction of a change in the ratio of Arid5a to Regnase-1.
On the diversity and statistical properties of protostellar discs
Authors: Bate Matthew R
Published: January 2018

We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation. Due to the chaotic nature of the star formation process, we find an enormous diversity of young protostellar discs, including misaligned discs, and discs whose orientations vary with time. Star–disc interactions truncate discs and produce multiple systems. Discs may be destroyed in dynamical encounters and/or through ram-pressure stripping, but reform by later gas accretion. We quantify the distributions of disc mass and radii for protostellar ages up to ≈105 yr. For low-mass protostars, disc masses tend to increase with both age and protostellar mass. Disc radii range from of order 10 to a few hundred au, grow in size on time-scales ≲ 104 yr, and are smaller around lower mass protostars. The radial surface density profiles of isolated protostellar discs are flatter than the minimum mass solar nebula model, typically scaling as Σ ∝ r−1. Disc to protostar mass ratios rarely exceed two, with a typical range of Md/M* = 0.1–1 to ages ≲ 104 yr and decreasing thereafter. We quantify the relative orientation angles of circumstellar discs and the orbit of bound pairs of protostars, finding a preference for alignment that strengths with decreasing separation. We also investigate how the orientations of the outer parts of discs differ from the protostellar and inner disc spins for isolated protostars and pairs.
The hepatitis C viral nonstructural protein 5A stabilizes growth-regulatory human transcripts
Authors: Guo Liang , Sharma Suresh D , Debes Jose D , Beisang Daniel , Rattenbacher Bernd , Louis Irina Vlasova-St , Wiesner Darin L , Cameron Craig E , Bohjanen Paul R
Published: January 2018

Numerous mammalian proto-oncogene and other growth-regulatory transcripts are upregulated in malignancy due to abnormal mRNA stabilization. In hepatoma cells expressing a hepatitis C virus (HCV) subgenomic replicon, we found that the viral nonstructural protein 5A (NS5A), a protein known to bind to viral RNA, also bound specifically to human cellular transcripts that encode regulators of cell growth and apoptosis, and this binding correlated with transcript stabilization. An important subset of human NS5A-target transcripts contained GU-rich elements, sequences known to destabilize mRNA. We found that NS5A bound to GU-rich elements in vitro and in cells. Mutation of the NS5A zinc finger abrogated its GU-rich element-binding and mRNA stabilizing activities. Overall, we identified a molecular mechanism whereby HCV manipulates host gene expression by stabilizing host transcripts in a manner that would promote growth and prevent death of virus-infected cells, allowing the virus to establish chronic infection and lead to the development of hepatocellular carcinoma.
Mandibular osteomyelitis due to Raoultella species
Authors: Lam Philip W. , Tadros Manal , Fong Ignatius W.
Published: January 2018

Introduction.
Raoultella is a genus of aerobic Gram-negative bacilli belonging to the family Enterobacteriaceae that are commonly found in water, soil and aquatic environments. With improved bacterial identification techniques, Raoultella species (namely R. planticola and R. ornithinolytica) have been an increasingly reported cause of infections in humans.

Case presentation. An 85-year-old man presented to hospital with a several-week history of left jaw pain and trismus. His medical history was significant for left mandibular osteomyelitis treated 1 year previously with amoxicillin-clavulanate. On admission, a computed tomography scan demonstrated a 2.6×1.7×1.6 cm peripherally enhancing collection surrounding the left posterior mandibular body. Two aspirates of the abscess grew a bacterium belonging to the genus Raoultella, with discordant species identification (R. ornithinolytica versus R. planticola) using two different techniques. A potential source of infection included a left lower molar tooth which was extracted months preceding the original diagnosis of osteomyelitis.

Conclusion. This is the first case of mandibular osteomyelitis caused by Raoultella species reported in the literature. In contrast to other forms of osteomyelitis, the pathogenesis of mandibular osteomyelitis involves contiguous spread from an odontogenic focus. Risk factors for mandibular osteomyelitis include a history of fracture, irradiation, diabetes and steroid therapy. This report adds to the growing literature of infections caused by this genus of bacteria, and raises the possibility of this organism’s role in odontogenic infections.
Topographer Reveals Dynamic Mechanisms of Cell Fate Decisions from Single-Cell Transcriptomic Data
Authors: Zhang Jiajun , Nie Qing , Zhou Tianshou
Published: January 2018

Cell fate decisions play a pivotal role in development but technologies for dissecting them are limited. We developed a multifunction new method, Topographer to construct a ‘quantitative’ Waddington’s landscape of single-cell transcriptomic data. This method is able to identify complex cell-state transition trajectories and to estimate complex cell-type dynamics characterized by fate and transition probabilities. It also infers both marker gene networks and their dynamic changes as well as dynamic characteristics of transcriptional bursting along the cell-state transition trajectories. Applying this method to single-cell RNA-seq data on the differentiation of primary human myoblasts, we not only identified three known cell types but also estimated both their fate probabilities and transition probabilities among them. We found that the percent of genes expressed in a bursty manner is significantly higher at (or near) the branch point (∼97%) than before or after branch (below 80%), and that both gene-gene and cell-cell correlation degrees are apparently lower near the branch point than away from the branching. Topographer allows revealing of cell fate mechanisms in a coherent way at three scales: cell lineage (macroscopic), gene network (mesoscopic) and gene expression (microscopic).