bluuebunny/crossref_metadata_2025 huggingface dataset:
El futuro de la evolución y de la especie humana ¿hacia una era post/trans-humanista?
Authors: Beorlegui Carlos
Published: June 2019

Current scientific research considers that we are in the brink of overcoming the boundaries of the human in order to get into a new age, called Post-Human or Trans-Human. This article proposes a clarification between these proposals to rethink what is to be consider human, as a well as a series of reflections that may help us to sort out their possibilities of becoming real. This effort forces us to think on the ideas we have about human essence, nature and condition, as well on the criteria and procedures we have to elucidate how to reach a consensus about the essentially open essence of humans. From there, we will be able to decide which proposals are legitimate and beneficial and which ones, on the contrary, entail the danger of bringing us closer to situations of in-humanity.
Realidad: Revista de Ciencias Sociales y Humanidades No. 152, 2018: 19-60
Hegel y las nuevas lógicas del mundo y del Estado. ¿Cómo ser revolucionario hoy?, de Ricardo Espinoza Lolas
Authors: Samour Héctor
Published: June 2019

No abstract available
Realidad: Revista de Ciencias Sociales y Humanidades No. 152, 2018: 193-203
PHENOMENOLOGICAL ANALYSIS OF A CONCEPTUAL WATERJET PROPULSOR BASED ON THE COANDA EFFECT
Authors: Lemos R. L. , Marques C. H. , Rocha L. A. , Isoldi L. A. , Santos E. D. dos
Published: June 2019

This work is part of a research project conceived at the Federal University of Rio Grande. The project aims to create and develop mechanical devices that use the Coanda effect to enhance their overall efficiency. The focus herein is analyzing the physical phenomenon occurring in a conceptual water-jet propulsor. In the proposed concept, a water-jet propulsor has its impeller replaced by injectors that produce the so-called Coanda effect, increasing thereby the mass flow rate. In order to simulate the flow through the propulsor, a numerical model was developed. In this model the time-averaged conservation equations of mass and momentum were solved numerically by the finite volume method, more precisely with the commercial package ANSYS FLUENT (version 14.0). For the closure of the constitutive equations, the k-ω URANS turbulence model was employed. The simulation was performed for a transient state with a timestep of ∆t = 1×10-3 s and a total physical time of t = 6.0 s. Static pressure fields, streamlines and speed profiles are used to analyze the equipment performance and the phenomenon occurrence. The results show that the Coanda Effect is able to generate thrust in a waterjet propulsion device without impeller. The study suggests that the employment of this principle has promising applicability in marine propulsion and deserves attention on future works.
NUMERICAL STUDY OF OIL SPILL IN THE PATOS LAGOON ESTUARY REGION
Authors: Leal T. L. , Monteiro C. B. , Silva M. C. , Möller O. O. , Oleinik P. H. , Marques W. C.
Published: June 2019

The consumption pattern of the world population is based on petroleum derivatives, which despite contributing to the improvement of the quality of life, has negative aspects, mainly in the environmental scope. The number of oil spills in water slide has increased significantly in recent years. Considering the complexity of the marine environment, the present work aims to apply a identification system of the dynamics and dispersion of oil, using the numerical modeling in the region of Franceses Bridge, near to Patos Lagoon-RS, Brazil. The study of hypothetical events of oil leakage in the region is of fundamental importance, since the Riograndense Petroleum Refinery is located inside of the Patos Lagoon estuary. A data structure of atmospheric and oceanic circulation was organized and inserted in the coupling between the hydrodynamic module Telemac-3D and the ECOS oil model, during the period between 2010 and 2013. The coupling of these models provided satisfactory results, requiring a level of computational effort favorable to obtaining of results capable of giving technical and scientific support to studies such as those of environmental impacts and contingency plans.
NUMERICAL STUDY COMPARING THE INCIDENCE INFLUENCE BETWEEN REALISTIC WAVE AND REGULAR WAVE OVER AN OVERTOPPING DEVICE
Authors: Hübner R. G. , Oleinik P. H. , Marques W. C. , Gomes M. N. , Santos E. D. dos , Machado B. N. , Isoldi L. A.
Published: June 2019

This work presents a numerical study to evaluate the difference between the fluid dynamic behavior of an overtopping device subjected to the incidence of a realistic wave when compared to a regular one; being this regular wave representative of the considered realistic sea state. To do so, the FLUENT software was employed, which is a Computational Fluid Dynamics package based on the Finite Volume Method. The regular wave was generated through a User Defined Function (UDF) that imposes its velocities components as boundary conditions of prescribed velocity. On the other hand, for the realistic wave it was used a methodology to impose the realistic components velocities from transient discrete values, named Table Data (TD) in FLUENT software. For both cases the Volume of Fluid (VOF) multiphase model was applied in the treatment of the water-air interaction. The results showed that the amount of water accumulated in the reservoir for the realistic sea state was 2.46 higher than for the regular wave. This is a relevant finding, since several researches about Overtopping device efficiency were promoted considering only the incidence of regular wave.
GEOMETRIC EVALUATION USING CONSTRUCTAL DESIGN OF A COASTAL OVERTOPPING DEVICE WITH DOUBLE RAMP CONSIDERING A REGULAR WAVE AND TIDAL VARIATION
Authors: Martins J. C. , Goulart M. M. , Isoldi L. A. , Santos E. D. dos , Gomes M. N. , Rocha L. A. O.
Published: June 2019

Concern for the environment and new ways of electricity generation, have led to studies of renewable energy sources, among these the Wave Energy Converters (WECs) are an option, however there are still many challenges to define how best to realize the conversion of the energy of the waves into electricity. In this work, a numerical study was carried out with the purpose of maximizing the available power (Pd) of a two-ramp overtopping device, considering the area fraction of ramps (ϕ1 and ϕ2) equal to 0.0006 and the ratio between height and length of the ramps (H1/L1 = H2/L2) equal to 0.3. The distance between the ramps (Lg) was varied in three values: 1.0; 1.5 and 2.0 m, besides three values for the free surface of water (h): 9.8; 10.0 and 10.2 m; simulating a tidal effect. The Constructal Design and Exhaustive Search methods were used, respectively, in the geometric evaluation (determination of a search field) and optimization. For the wave generation, the Second Order Stokes Theory was used, with wave period (T) of 7.5 s and wave height (H) 1.0 m. The results showed that there was no accumulation of water in the upper ramp of the device, in addition, with the increase of Lg there was an increase of Pd in h = 10.0 and 10.2 m, and Pd kept practically constant in h = 9, 8 m. And, as expected, with increasing of h, there was an increase in Pd.
THE ADO METHOD FOR SOLVING ONE-DIMENSIONAL DEEP-PENETRATION TRANSPORT PROBLEMS
Authors: Ribeiro D. L. , Rodrigues M. P. , Prolo Filho J. F.
Published: June 2019

In this work, the Analytical Discrete Ordinate method (ADO method) is used to solve deep-penetration transport problems in one-dimensional Cartesian geometry, subject to isotropic and linear anisotropic scattering effects. The regime is considered permanent, the media are homogeneous, and the fluxes are caused by sources located on the boundaries of the domain. In addition, the energy fluctuations will be considered as not significant, characterizing the phenomena as monoenergetic problems. In order to validate the code, method and provide benchmark results, some test problems will be treated and results will be discussed. In particular, the ADO method generated fairly accurate results when compared to other methods based on SN approaches, at a relatively low computational cost.
Knowledge and Usage of Cervical Cancer Screening for Cancer Prevention by Reproductive Age Women
Authors: Ofuebe Justina I. , Omaka Lois N. , Asogwa Blessing O. , Agu Michael A. , Ugwu Uchenna C.
Published: June 2019

Cervical cancer –CCa screening is an effective measure mapped out for preventing cancer occurrences in women. This study determined the status of knowledge and usage of CCa screening for cancer prevention among reproductive age Nigerian women. The study was based on descriptive research design and was conducted in Nigeria, from October 2017 to April 2018 and comprised of reproductive age women. The participants, aged 15-49 years, were vulnerable to CCa. The instrument used for data collection was structured questionnaire. Statistical Package for Social Science version 21 was used for data analysis. All the participants were Nigerians totalling 1300. Of all, 1249(96.1%) completed the questionnaire correctly. Majority of the participants were: Christians 825(66.0%), Single 695(55.6%), aged 26-35 years 673(53.8%), and had Secondary education 753(60.2%). A greater proportion of the participants 1073(86.7%) knew about CCa screening. Among them, only 513(41.7%) were screened. The status of knowledge and usage of CCa screening varied within variables. A statistically significant difference was observed with regards to Age by birth (P-value <0.05) while none existed on marital status, religion and educational level (P-value >0.05). There is obvious gap between what is known about CCa screening service for cancer prevention and the actual usage by the women. The majority of the women knew about the available services but only few of them had used it. This implies that there is obvious imbalance between the quality of knowledge of a given health service and the actual usage.
SIMULATION TESTS OF ADAPTIVE CONTROL STRATEGIES
FOR CNC MACHINE TOOLS
Authors: STRYCZEK Roman , SZCZEPKA Wojciech
Published: June 2019

The issue addressed in the article concerns the current needs and possibilities of computer-aided design
of adaptive control strategies in machining processes. A simulative method of selecting the adaptive feed control strategy while rough turning materials difficult to machine, effective and inexpensive in its implementation, based on controlling the load placed on the machine's drives, has been presented. The results of a number
of virtual tests of the proposed feed control strategy have been included, while paying particular attention to the stability of the machining process during moments of sudden change in the machining allowance. The obtained results meet the accepted quality indicators of the control algorithm. At the same time, the experiences collected by the author while conducting the tests confirmed the complexity of the issue and the resulting necessity to implement a comprehensive simulation testing program.
PADDLE SHAPE OPTIMIZATION FOR HOLE-FLANGING BY PADDLE FORMING THROUGH THE USE OF A PREDEFINED STRAIN PATH IN FINITE ELEMENT ANALYSIS
Authors: BESONG Lemopi Isidore , BUHL Johannes , BAMBACH Markus
Published: June 2019

This research investigates a novel hole-flanging process by paddle forming through the use of finite element (FE) simulations. Paddles of different shapes rotating at high speeds were used to deform clamped sheets with pre-drilled holes at their centers. The results of the simulations show that the paddle shape determines
the geometry and principal strains of the formed flanges. A convex-shaped paddle forms flanges with predominant strains in the left quadrant of the forming limit diagram (FLD). However, the convex paddle promotes unwanted bulge formation at the clamped end of the flange. A concave paddle forms flanges with no bulge but the principal strains of elements in the middle section of the flange are in the right quadrant of the FLD which indicates an increased probability for crack occurrence. An optimization of the paddle shape was conducted to prevent bulging at the clamped end while avoiding crack occurrence. The paddle shape was optimized by mapping the deformation of some elements along the flange length to a pre-defined strain path on the FLD while maintaining the bulge height within the desired geometric tolerance. The radii and lengths
of the paddle edge were varied to obtain an optimum paddle shape.
EXPERIMENTAL INVESTIGATIONS OF THE BONDING ZONE
IN THE EXPLOSIVE WELDING OF A DIFFERENTLY STRUCTURED
STEEL-ZIRCONIUM PLATERS
Authors: PRAZMOWSKI Mariusz , PAUL Henryk
Published: June 2019

In this work the results of trials aimed at selecting optimal settings of the explosion welding process of 10 mm thick zirconium (Zr 700 grade) plates with carbon steel (P265GH grade) are presented. A bimetal Zr-steel and trimetal Zr-Ti-steel and Zr-Zr-steel where: 2 mm Ti and 3 mm Zr were used as a technological intermediate layer facilitating the bonding. The research was carried out for as-bonded joints, i.e. immediately following explosion welding. Structural analyses in leyers near the interface were focused on the characteristic of the joint interface. Mechanical properties of the obtained clads were measured with shearing, peel and lateral bending tests. Systematic measurements of microhardness distribution enabled analyzing the strain-hardening of the material resulting from explosion welding both at the bond interface zone and throughout the whole section of the clad.
It was established that during explosion welding with 10 mm Zr 700 the application of the 2 mm or 3 mm thick interlayers of Zr70 or Ti grade 1, respectively, allows obtaining a joint with good mechanical properties and optimal characteristic of the interface.
Das BVerfG zwischen Verfassungsinterpretation, europäischer Integration und politischer Positionierung – Eine Zwischenbilanz zum NPD-Verbotsurteil vom 17.1.2017
Authors: Känner Lise
Published: June 2019

In this paper, the author examines the effects that the judgment of the German Constitutional Court concerning the party ban in Art. 21 I GG (17 January 2017) had on government, legislator and society since it was rendered roughly two years ago. For this purpose, she illustrates the relevant changes of the procedural and substantive law of Art. 21 GG and analyses the historical and political background of those changes. She puts special emphasis on the influence that the case law of the ECHR had on the new interpretation of Art. 21 GG. In the end, she questions whether the judgment, which on the surface emphasises the importance of strengthening the freedom of political parties, is able to live up to it’s own standards in reality. For this, she studies to what extent state repression (also, and in particular illegal one) of political parties has increased during the time since the judgment.
Hilma af Klint: do espírito à matéria
Authors:   Universidade Presbiteriana Mackenzie, Cheles Anna Carolina
Published: June 2019

As múltiplas questões a respeito do trabalho esotérico de Hilma af Klint estão cada vez mais pertinentes no contemporâneo, a movimentação em torno da artista não é à toa. De um duvidoso título de precursora da vanguarda abstracionista a um elo expressivo entre o mundo espiritual e o material, a artista ganha destaque pelas coincidentes trajetórias no universo artístico de Wassily Kandinsky e Piet Mondrian, através de conceitos e filosofias baseadas na Teosofia de Helena Blavatsky e Rudolf Steiner, a qual estaria em grande circulação a propósito de uma busca espiritual frente ao progresso modernista no final do século XIX. As potências artísticas de Hilma af Klint são ainda imensuráveis, mas é notável seu caráter ímpar diante de seus contemporâneos, a ponto de indagar o que Walter Benjamin conceituaria como caráter aurático das obras de arte, uma vez que sua obra tensiona o secular e o divino, o tradicional e o moderno, através de uma prática de inspiração mediúnica. Hilma af Klint é uma artista sacerdótica, é preciso despir-se de todo formalismo artístico para compreender sua arte fundamentalmente etérea e cósmica.
NANOTEHNOLOGIJE U GRAĐEVINSKIM MATERIJALIMA
Authors: Vučenović Siniša M , Šetrajčić Jovan P
Published: June 2019

Nanotehnologije su u stanju pružiti velike mogućnosti u unapređivanju, prvenstveno termodinamičkih i mehaničkih, osobina građevinskih materijala, najčešće betona i betonskih konstrukcija. Nanomaterijali poboljšavaju održivost, izdržljivost, ali i neka druga svojstva kao što je, npr., mogućnost samočišćenja. Naučna istraživanja nanostruktura su u stalnom porastu, pružajući nova saznanja o potencijalu njihove primjene u građivinarstvu, čime se otvaraju mnogobrojne mogućnosti u poboljšanju karakteristika, ali i smanjenju troškova proizvodnje i ugradnje građevinskih materijala. Ovaj rad će dati pregled nekih osnovnih definicija nanotehnologija i karakterizacije nanostruktura, kao i nanoaditiva koji su danas najznačajniji u unapređenju građevinskih (betonskih) proizvoda.
АНАЛИЗА СТАНДАРДА ЗА 3D МОДЕЛОВАЊЕ ГРАДОВА И УПРАВЉАЊЕ ПРОСТОРОМ
Authors: Милованов Стеван , Русковски Игор , Говедарица Миро
Published: June 2019

Географски информациони системи пружају основне информације о окружењу и представљају полазну основу за развој различитих апликација које налазе примену у широком спектру делатности. Ови системи, између осталог, користе и 3D геореференциране податке који могу настати из различитих извора. У овом раду дате су карактеристике стандарда који су развијени за потребе моделовања простора, као и анализа софтверске архитектуре система који може бити примењен за потребе решавања овог проблема. Одабрано решење је искоришћено на тест подацима на подручју Петроварадинске тврђаве у Новом саду и једном од објеката на подручју Универзитета у Новом Саду.
Cultivating the uncultivable environmental microbe using insights from whole genome sequence that define a growth medium
Authors: Ng Wenfa
Published: June 2019

While many microbes could be cultivated in the laboratory, many more resist attempts at bringing them under cultivation through a variety of environmental and nutritional conditions. This represents the current state of microbiology where we still lack knowledge and tools concerning the appropriate conditions and medium for cultivating hitherto unculturable microbes. Many approaches have been proposed for improving the subset of environmental microbes that could be cultivated, but these remain specific methods not generally applicable under all circumstances. One potential general solution to the problem is to use insights from whole genome sequence of environmental microbes for understanding the environmental and nutritional conditions conducive for its cultivation. For example, reconstruction of the metabolic network of a microbe from annotated whole genome data would reveal whether the microbe pursue an aerobic or anaerobic lifestyle. Specifically, presence of enzymes mediating processes involving anaerobic electron acceptors strongly suggest an anaerobic lifestyle. After fixing the oxygen tension of the cultivation medium, the next question to ask involves the types of nutrients that could be uptake by cells. Profiling the types of transporters available to the microbe would largely answer its capability of transporting different nutrients into the cell. When such nutrients are coupled to metabolic pathway that aid their catabolism, they can be provided in the medium to provide the carbon backbone for forming different intermediates needed by the cell. But, most microbes are deficient in some enzymes that build specific intermediates required for biomass formation. Lack of such intermediates would thus prevent cell growth, and these metabolites would need to be provided in the nutrient medium. Moving beyond nutrients, the genome sequence could also offer clues to the pH requirement of the microbe. This can be gleaned from the presence of homologous enzymes known to facilitate survival at low or high pH. However, such knowledge remains guesswork where experiments are needed to fine tune the pH for optimal cell growth. Finally, requirement for essential micronutrients such as trace metals could be deciphered from the presence of metal-cofactor enzymes in the annotated genome. Requirement for vitamins in the growth medium could similarly be deduced from the presence/absence of vitamin synthesis pathways in the microbe. This helps to concoct the trace metal and nutrient solution needed by the cells. Collectively, while the approach outlined above is theoretically feasible, experimental work remain essential in delineating the nutritional and environmental conditions needed by particular microbe for growth. But, information from whole genome sequence do offer help in selecting the range of conditions for experimentation; thereby, reducing the time, expense and effort needed to bring a microbe into cultivation in the laboratory.
Practical considerations for collaborative research between the pharmaceutical industry and external investigators
Authors: Lloyd Maureen , Barbitsch Cynthia K , Voehl Hirsch Mary , Panayi Antonia , Southam Eric
Published: June 2019

Traditionally, clinical research has been conducted via either industry sponsored studies or non-industry investigator sponsored studies. Collaborative Research provides a relatively new mechanism for industry and non-industry partners to work together in the pursuit of effective and safe treatments for the patient. The aims of this article are to provide both industry and non-industry investigators with a greater insight into the complex processes that are currently employed by industry when entering into Collaborative Research agreements, and to encourage consistency and transparency in approach across companies.

In Collaborative Research, instead of being limited to providing funding and/or product, the industry partner contributes expertise complementary to that of the non-industry partner, who is the sponsor of the study. Collaborative Research may be conducted before, during or after regulatory approval of a drug or medical device, and may be interventional, observational or preclinical.

A collaboration requires appropriate process and governance frameworks to be established in order to be successful. Important considerations include the routes for submitting a request, the review and approval process, due diligence criteria, budgeting and contracting processes, permissible interactions during the execution of the research, the closing out of the research, and dispute resolution. It is also necessary to have in place an agreed communication strategy and a risk control framework. Clear and specific contract language around roles and responsibilities, intellectual property, rights to data, registration and disclosure of publications, and an understanding of adverse event reporting procedures are other critical facets of Collaborative Research that are essential to avoid delays and disputes.

With no global standards for Collaborative Research, it is important that partners establish practical procedures, good ongoing communication, alignment of goals, and transparent interactions and disclosure to jointly advance the science of new, safe and effective therapies.
Engaging toddlers in interactions during meals: group-related joint attention
Authors: Os Ellen
Published: June 2019

Knowledge on how caregivers engage and interact with groups of toddlers in childcare settings is limited. Practice in toddler care is often based on individual approaches even though childcare is a group setting. This study focused on how caregivers created joint attention with toddlers in 12 groups during mealtimes. The results showed that some caregivers took the lead and engaged their groups in sustained joint attention episodes. The children in these groups seemed to be engaged in interactions that involved multiple children and had a rich variety of content. Other caregivers seemed unengaged, and their groups had few, brief interactions that mostly did not meet the criteria for joint attention. In these groups, the interactions largely consisted of rules and regulations.
Keywords: Caregiver-toddler interactions, group-related joint attention, mealtimes, toddler childcare
Protein‐facilitated transport of hydrophobic molecules across the yeast plasma membrane
Authors: Claus Silke , Jezierska Sylwia , Van Bogaert Inge N. A.
Published: June 2019

In yeasts, the plasma membrane forms the barrier that protects the cell from the outside world, but also gathers and keeps valuable compounds inside. Although it is often suggested that hydrophobic molecules surpass this checkpoint by simple diffusion, it now becomes evident that protein‐facilitated transport mechanisms allow for selective import and export of triglycerides, fatty acids, alkanes, and sterols in yeasts. During biomass production, hydrophobic carbon sources enter and exit the cell efficiently in a strictly regulated manner that helps avoid toxicity. Furthermore, various molecules, such as yeast pheromones, secondary metabolites and xenobiotics, are exported to ensure cell–cell communication, or increase chances of survival. This review summarizes the current knowledge on how hydrophobic compounds interact with protein‐facilitated transport systems on the plasma membrane and how selective import and export across the yeast plasma membrane is achieved. Both the model organism Saccharomyces cerevisiae, as well as unconventional yeasts are discussed.
Tension Pistons: Amplifying Piston Force Using Fluid‐Induced Tension in Flexible Materials
Authors: Li Shuguang , Vogt Daniel M. , Bartlett Nicholas W. , Rus Daniela , Wood Robert J.
Published: June 2019

Pistons are ubiquitous devices used for fluid‐mechanical energy conversion. However, despite this ubiquity and centuries of development, the forces and motions produced by conventional rigid pistons are limited by their design. The use of flexible materials and structures opens a door to the design of a piston with unconventional features. In this study, an architecture for pistons that utilizes a combination of flexible membrane materials and compressible rigid structures is proposed. In contrast to conventional pistons, the fluid‐pressure‐induced tension forces in the flexible membrane play a primary role in the system, rather than compressive forces on the internal surfaces of the piston. The compressive skeletal structures offer the opportunity for the production of tunable forces and motions in the “tension piston” system. The experimental results indicate that the tension piston concept is able to produce substantially greater force (more than three times), higher power, and higher energy efficiency (more than 40% improvement at low pressures) compared to a conventional piston, and these features enable myriad potential applications for the tension piston as a drop‐in replacement for existing pistons.
Skin‐Inspired Antibacterial Conductive Hydrogels for Epidermal Sensors and Diabetic Foot Wound Dressings
Authors: Zhao Yue , Li Zuhao , Song Shanliang , Yang Kerong , Liu Hou , Yang Zhe , Wang Jincheng , Yang Bai , Lin Quan
Published: June 2019

Recently, artificial intelligence research has driven the development of stretchable and flexible electronic systems. Conductive hydrogels are a class of soft electronic materials that have emerging applications in wearable and implantable biomedical devices. However, current conductive hydrogels possess fundamental limitations in terms of their antibacterial performance and a mechanical mismatch with human tissues, which severely limits their applications in biological interfaces. Here, inspired by animal skin, a conductive hydrogel is fabricated from a supramolecular assembly of polydopamine decorated silver nanoparticles (PDA@Ag NPs), polyaniline, and polyvinyl alcohol, namely PDA@Ag NPs/CPHs. The resultant hydrogel has many desirable features, such as tunable mechanical and electrochemical properties, eye‐catching processability, good self‐healing ability as well as repeatable adhesiveness. Remarkably, PDA@Ag NPs/CPHs exhibit broad antibacterial activity against Gram‐negative and Gram‐positive bacteria. The potential application of this versatile hydrogel is demonstrated by monitoring large‐scale movements of the human body in real time. In addition, PDA@Ag NPs/CPHs have a significant therapeutic effect on diabetic foot wounds by promoting angiogenesis, accelerating collagen deposition, inhibiting bacterial growth, and controlling wound infection. To the best of the authors' knowledge, this is the first time that conductive hydrogels with antibacterial ability are developed for use as epidermal sensors and diabetic foot wound dressing.
Polarized Ferroelectric Polymers for High‐Performance Perovskite Solar Cells
Authors: Zhang Cong‐Cong , Wang Zhao‐Kui , Yuan Shuai , Wang Rui , Li Meng , Jimoh Musibau Francis , Liao Liang‐Sheng , Yang Yang
Published: June 2019

In hybrid organic–inorganic lead halide perovskite solar cells, the energy loss is strongly associated with nonradiative recombination in the perovskite layer and at the cell interfaces. Here, a simple but effective strategy is developed to improve the cell performance of perovskite solar cells via the combination of internal doping by a ferroelectric polymer and external control by an electric field. A group of polarized ferroelectric (PFE) polymers are doped into the methylammonium lead iodide (MAPbI3) layer and/or inserted between the perovskite and the hole‐transporting layers to enhance the build‐in field (BIF), improve the crystallization of MAPbI3, and regulate the nonradiative recombination in perovskite solar cells. The PFE polymer‐doped MAPbI3 shows an orderly arrangement of MA+ cations, resulting in a preferred growth orientation of polycrystalline perovskite films with reduced trap states. In addition, the BIF is enhanced by the widened depletion region in the device. As an interfacial dipole layer, the PFE polymer plays a critical role in increasing the BIF. This combined effect leads to a substantial reduction in voltage loss of 0.14 V due to the efficient suppression of nonradiative recombination. Consequently, the resulting perovskite solar cells present a power conversion efficiency of 21.38% with a high open‐circuit voltage of 1.14 V.
Improved Interfaces of Mechanically Modified Lithium Electrodes with Solid Polymer Electrolytes
Authors: Liebenau Dominik , Jalkanen Kirsi , Schmohl Sebastian , Stan Marian C. , Bieker Peter , Wiemhöfer Hans‐Dieter , Winter Martin , Kolek Martin
Published: June 2019

The combination of mechanically modified lithium electrodes and solid polymer electrolytes (SPEs) is investigated. So far, modified lithium electrodes, e.g., via structuring, are successfully used in combination with liquid electrolytes like ionic liquid‐based and organic solvent‐based ones. Specific SPEs have proven to be well compatible with lithium metal, even better than with liquid electrolytes. Nevertheless, the interface between lithium and SPEs is a complex issue. In this work, the challenge of the adequate wetting of the lithium electrode surface, especially a structured lithium surface, with a solid polymer is faced to successfully improve the interfacial properties and thus the performance, by a new method for the coating of such electrodes. The wetting of the micropatterned lithium surface by the SPE and the directed lithium electrodeposition in the patterns are verified by scanning electron microscopy analysis. The electrochemical properties of Li|SPE assemblies are investigated on the basis of constant current cycling and impedance experiments.
Nanostructure and Mechanism of Metal Deposition by a Laser‐Induced Photothermal Reaction
Authors: Greenberg Ehud , Armon Nina , Kapon Omree , Ben‐Ishai Moshit , Shpaisman Hagay
Published: June 2019

Laser‐induced photothermal reaction of metal ions is a promising one‐step method for production of conductive micropatterns for electronic devices and sensors. However, the mechanism that governs the process in which thermally activated materials are deposited on a substrate is not clear. Here, light is shed on the mechanism through systematic analysis of photothermal reaction products forming iron oxide and silver at different interfaces. Examination of the nanostructure of deposits on a substrate using high‐resolution transmission electron microscopy and selected area diffraction pattern analysis reveals a combination of both amorphous and crystalline moieties. It is found that focusing the laser inside the solution leads to exclusive formation of crystalline products, while focusing at the liquid/air interface leads to formation of amorphous products due to kinetic considerations. Ring‐shaped microstructures observed on the substrate indicate that microbubbles are involved in the deposition. The findings suggest that crystalline nanoparticles formed in solution are pinned to the base of the microbubbles. These stationary deposits absorb the laser light, resulting in extensive local heating, which leads to a fast thermal‐reaction of the metal ions that are added as amorphous nanostructures. The presence of both crystalline and amorphous nanostructures therefore results from two different mechanisms.
Controlling Cell Behavior through the Design of Biomaterial Surfaces: A Focus on Surface Modification Techniques
Authors: Amani Hamed , Arzaghi Hamidreza , Bayandori Mehrdad , Dezfuli Amin Shiralizadeh , Pazoki‐Toroudi Hamidreza , Shafiee Abbas , Moradi Lida
Published: June 2019

Surface interaction at the biomaterial–cell interface is essential for a variety of cellular functions, such as adhesion, proliferation, and differentiation. Nevertheless, changes in the biointerface enable to trigger specific cell signaling and result in different cellular responses. In order to manufacture biomaterials with higher functionality, biomaterials containing immobilized bioactive ligands have been widely introduced and employed for tissue engineering and regenerative medicine applications. Moreover, a number of physical and chemical strategies have been used to improve the functionality of biomaterials and specifically at the material interface. Here, the interactions between materials and cells at the interface levels are described. Then, the importance of surface properties in cell function is discussed and recent methods for surface modifications are systematically highlighted. Additionally, the impact of bulk material properties on the cellular responses is briefly reviewed.
A N, P Dual‐Doped Carbon with High Porosity as an Advanced Metal‐Free Oxygen Reduction Catalyst
Authors: Sun Ya‐Nan , Zhang Ming‐Li , Zhao Li , Sui Zhu‐Yin , Sun Zhen‐Yu , Han Bao‐Hang
Published: June 2019

Oxygen reduction reaction (ORR) is the critical reaction in metal–air batteries and fuel cells. This reaction suffers from sluggish kinetics and use of Pt‐based catalysts that are prohibitively expensive and in shortage of resource. Therefore, an alternative advanced metal‐free catalyst for ORR is highly desired. Herein, a N, P dual‐doped porous carbon (NPPC) with large surface area is obtained through the CO2 activation of a novel N, P‐doped aerogel (NPA). Ascribed to the CO2 activation of NPA, NPPC possesses a large Brunauer–Emmett–Teller specific surface area (2850 m2 g−1) and N, P dual doping. CO2 activation as an environmentally friendly method with no corrosion can not only produce abundant micropores and mesopores in NPPC, but also provide a positive influence for the transformation of N species from pyrrolic N to pyridinic and graphitic N, which can promote the ORR activities. Therefore, compared with carbonized NPA, NPPC exhibits a higher ORR activity, including a larger transfer electron number (3.95 at 0.2 V vs reversible hydrogen electrode). Additionally, NPPC possesses a much better long‐term stability compared with commercial 20 wt% Pt/C. This work gives an inspiration on the new strategy for preparing the future catalyst for ORR.
Multimechanism Synergistic Photodetectors with Ultrabroad Spectrum Response from 375 nm to 10 µm
Authors: Wang Xudong , Shen Hong , Chen Yan , Wu Guangjian , Wang Peng , Xia Hui , Lin Tie , Zhou Peng , Hu Weida , Meng Xiangjian , Chu Junhao , Wang Jianlu
Published: June 2019

Broadening the spectral range of photodetectors is an essential topic in photonics. Traditional photodetectors are widely used; however, the realization of ultrabroad spectrum photodetectors remains a challenge. Here, a photodetector constructed by a hybrid quasi‐freestanding structure of organic ferroelectric poly(vinylidene fluoride–trifluoroethylene) (P(VDF‐TrFE)) with molybdenum disulfide (MoS2) is demonstrated. The 2D MoS2 with the ultrathin structure brings a great benefit of heat dissipation for the pyroelectric infrared detector. By coupling the mechanisms of pyroelectrics, photoconductor, and phototransistor effect, an ultrabroad spectrum response ranging from ultraviolet (375 nm) to long‐wavelength infrared (10 µm) is achieved. In the 2.76–10 µm spectral range, the 2D MoS2 is used to read and amplify the photocurrent induced by the pyroelectric effect of P(VDF‐TrFE). The sensitivity of the device in this spectral range is greatly enhanced. A high responsivity of 140 mA W−1, an on/off photocurrent switching ratio up to 103, and a quick response of 5.5 ms are achieved. Moreover, the ferroelectric polarization field dramatically enhances the photoconductive properties of MoS2 and restrains dark current and noise. This approach constitutes a reliable route toward realizing high‐performance photodetectors with a remarkable ultrabroad spectrum response, high responsivity, low power consumption, and room‐temperature operation.
Creation of 3D Textured Graphene/Si Schottky Junction Photocathode for Enhanced Photo‐Electrochemical Efficiency and Stability
Authors: Ku Che‐Kuei , Wu Po‐Hsien , Chung Cheng‐Chu , Chen Chun‐Chi , Tsai Kai‐Jie , Chen Hung‐Ming , Chang Yu‐Cheng , Chuang Cheng‐Hao , Wei Chuan‐Yu , Wen Cheng‐Yen , Lin Tzu‐Yao , Chen Hsuen‐Li , Wang Yen‐Shang , Lee Zhe‐Yu , Chang Jun‐Ru , Luo Chih‐Wei , Wang Di‐Yan , Hwang Bing Joe , Chen Chun‐Wei
Published: June 2019

This work presents a novel photo‐electrochemical architecture based on the 3D pyramid‐like graphene/p‐Si Schottky junctions. Overcoming the conventional transfer technique by which only planar graphene/Si Schottky junctions are currently available, this work demonstrates the 3D pyramid‐like graphene/p‐Si Schottky junction photocathode, which greatly enhances light harvesting efficiency and exhibits promising photo‐electrochemical performance for hydrogen generation. The formation of 3D pyramid‐like graphene/p‐Si Schottky junctions exhibits enhanced electrochemical activity and promotes charge separation efficiency compared with the bare pyramid Si surface without graphene. The inherent chemical inertness of graphene significantly improves the operational stability of 3D graphene/p‐Si Schottky junction photo‐electrochemical cells. The 3D pyramid‐like graphene/p‐Si Schottky junction photocathode delivers an onset potential of 0.41 V and a saturated photocurrent density of −32.5 mA cm−2 at 0 V (vs RHE) with excellent stability comparable to values reported for textured or nanostructured p‐Si photocathodes coated with ultrathin oxide layers by the conventional atomic layer deposition technique. These results suggest that the formation of graphene/Si Schottky junctions with a 3D architecture is a promising approach to improve the performance and durability of Si‐based photo‐electrochemical systems for water splitting or solar‐to‐fuel conversion.
Hydrodynamics and simulation of air–water homogeneous bubble column under elevated pressure
Authors: Tran Bay V. , Nguyen Dan D. , Ngo Son I. , Lim Young‐Il , Kim Bongjun , Lee Dong Hyun , Go Kang‐Seok , Nho Nam‐Sun
Published: June 2019

A gas–liquid Eulerian computational fluid dynamics (CFD) model coupled with a population balance equation (PBE) was presented to investigate hydrodynamics of an air–water bubble column (1.8 m in height and 0.1 m in inner diameter) under elevated pressure in terms of pressure drop, gas holdup, mean bubble size, and bubble surface area. The CFD‐PBE model was modified with three pressure correction factors to predict both the total gas holdup and the mean bubble size in the homogeneous bubbly flow regime. The three correction factors were optimized compared to experimental data. Increasing the pressure led to increasing the density, reducing the bubble size, and increasing the gas holdup. The bubble size distribution moved toward a smaller bubble size, as the pressure increased. The modified CFD‐PBE model validated with experimental data and empirical models represented well hydrodynamics of the bubble column at P = 0.1, 1.5, and 3.5 MPa.
Magnetische Levitation in Chemie, Materialwissenschaft und Biochemie
Authors: Ge Shencheng , Nemiroski Alex , Mirica Katherine A. , Mace Charles R. , Hennek Jonathan W. , Kumar Ashok A. , Whitesides George M.
Published: June 2019

Alle Materie hat Dichte. Die Aufzeichnungen der Verwendung von Dichte zur Charakterisierung von Materie gehen auf das Jahr ca. 250 v. Chr. zurück, als Archimedes das “Rätsel der Königskrone” mit Hilfe der Dichte gelöst haben soll.[1] Heute werden Dichtemessungen zur Trennung und Charakterisierung einer Reihe von Materialien (inklusive Zellen und Organismen) und deren chemischen und/oder physikalischen Veränderungen in Zeit und Raum verwendet. Dieser Aufsatz beschreibt eine dichtebasierende Technik – magnetische Levitation, der Einfachheit halber nennen wir sie “MagLev” –, die zur Lösung von Problemen in den Bereichen der Chemie, Materialwissenschaft und Biochemie entwickelt wurde. MagLev hat zwei Hauptmerkmale – Einfachheit und Anwendbarkeit auf ein breites Spektrum von Materialien –, die sie für eine Reihe von Anwendungen nützlich macht (z. B. Materialcharakterisierung, Qualitätskontrolle von Plastik‐Fertigteilen, Selbstorganisation von Objekten in 3D, Trennung verschiedener Arten von biologischen Zellen, und Bioanalysen). Die Einfachheit und Anwendungsbreite ermöglichen auch den Einsatz in ressourcenschwachen Gebieten (z. B. bei der Bewertung der Wasser‐ und Lebensmittelqualität und bei der Diagnose von Krankheiten).
Step‐Growth Coordination Polymerization of 5‐Hydroxymethyl Furfural with Dihydrosilanes: Synergistic Catalysis Using Heteroscopionate Zinc Hydride and B(C6F5)3
Authors: Li Chuanyang , Wang Lingfang , Wang Meiyan , Liu Bo , Liu Xinli , Cui Dongmei
Published: June 2019

The utilization of 5‐hydroxymethyl furfural (HMF) as a renewable feedstock for polymer synthesis has not yet been achieved as it is structurally asymmetric and contains three active functional groups. Reported here is the unprecedented step‐growth copolymerization of HMF and dihydrosilanes, through a coordination mechanism, to afford linear poly(silyl ether)s in the presence of B(C6F5)3 and the heteroscorpionate zinc hydride complex LZnH [L=(MePz)2CP(Ph)2NPh, MePz=3,5‐dimethylpyrazolyl]. The adduct B(C6F5)3⋅⋅⋅H⋅⋅⋅Zn, confirmed by NMR spectroscopy and DFT calculations, plays a key role in the synergistic catalysis, where B(C6F5)3 activates ZnH and stabilizes the Zn+ active species, and the sterically bulky ZnH effectively inhibits (C6F5)3B from reacting with dihydrosilane to form (C6F5)3B‐H‐Si, which facilely initiates ring opening of furan. The mechanism was studied by DFT simulations.
An Antitumor Bis(N‐Heterocyclic Carbene)Platinum(II) Complex That Engages Asparagine Synthetase as an Anticancer Target
Authors: Hu Di , Yang Chen , Lok Chun‐Nam , Xing Fangrong , Lee Pui‐Yan , Fung Yi Man Eva , Jiang Haibo , Che Chi‐Ming
Published: June 2019

New anticancer platinum(II) compounds with distinctive modes of action are appealing alternatives to combat the drug resistance and improve the efficacy of clinically used platinum chemotherapy. Herein, we describe a rare example of an antitumor PtII complex targeting a tumor‐associated protein, rather than DNA, under cellular conditions. Complex [(bis‐NHC)Pt(bt)]PF6 (1 a; Hbt=1‐(3‐hydroxybenzo[b]thiophen‐2‐yl)ethanone) overcomes cisplatin resistance in cancer cells and displays significant tumor growth inhibition in mice with higher tolerable doses compared to cisplatin. The cellular Pt species shows little association with DNA, and localizes in the cytoplasm as revealed by nanoscale secondary ion mass spectrometry. An unbiased thermal proteome profiling experiment identified asparagine synthetase (ASNS) as a molecular target of 1 a. Accordingly, 1 a treatment reduced the cellular asparagine levels and inhibited cancer cell proliferation, which could be reversed by asparagine supplementation. A bis‐NHC‐ligated Pt species generated from the hydrolysis of 1 a forms adducts with thiols and appears to target an active‐site cysteine of ASNS.
Kationen‐gesteuerte Bildung und Umwandlung der fac/fac‐ und mer/mer‐Stereoisomere eines dreisträngigen Helicats
Authors: Chen Xiaofei , Mevissen Christian , Huda Saskia , Göb Christian , Oppel Iris M. , Albrecht Markus
Published: June 2019

Zwei Biscatecholesterliganden mit Oligoether‐Verbrückung wurden eingesetzt, um zweikernige Triscatecholattitan(IV)‐basierte Helicate herzustellen. Im Fall von Li4[(1/2)3Ti2] wurden “klassische” Helicate mit drei intern gebundenen Li+ und einer syn‐Orientierung der Liganden in den Komplexen (fac/fac‐Isomer) erhalten. Im Fall des Natriumsalzes Na4[(2)3Ti2] wird ein andersartiges homochirales zweikerniges, dreisträngiges Helicat mit zwei internen Nariumionen gebildet. Die Komplexeinheiten sind hier anti‐konfiguriert, wobei zwei der verbrückenden Einheiten innere Positionen der Liganden im Helicat mit äußeren verknüpfen (mer/mer‐Isomer). Entfernen der Natriumkationen und Zugabe von Lithiumionen führt zum Schalten von der einen topologischen Form zur Anderen, wobei ein gestrecktes Helicat [(2)3Ti2]4− als Zwischenstufe entsteht. Das Zurückschalten zu dem “nicht‐klassischen” Helicat ist nicht möglich, da hierbei zu große strukturelle Änderungen nötig sind.
Encapsulation of a Phase‐Change Material in Nanocapsules with a Well‐Defined Hole in the Wall for the Controlled Release of Drugs
Authors: Qiu Jichuan , Huo Da , Xue Jiajia , Zhu Guanghui , Liu Hong , Xia Younan
Published: June 2019

As a class of biocompatible and biodegradable phase‐change materials, natural fatty acids have received considerable interest in recent years for temperature‐controlled release of drugs. However, the poor dispersibility and colloidal stability of their nanoparticles under physiological conditions place a major limitation on their applications in biomedicine. Herein, we report a facile method for encapsulating a mixture of two natural fatty acids (with a eutectic melting point at 39 °C) in a biocompatible, silica‐based nanocapsule to achieve both stable dispersion and controllable release of drugs. The nanocapsules have a well‐defined hole in the wall to ensure easy loading of fatty acids, together with multiple types of functional components such as therapeutics and near‐infrared dyes. The payloads can be released through the hole when the fatty acids are melted upon photothermal heating. The release profile can be controlled by varying the size of the hole and/or the duration of laser irradiation.
Site‐Selective Occupancy of Eu2+Toward Blue‐Light‐Excited Red Emission in a Rb3YSi2O7:Eu Phosphor
Authors: Qiao Jianwei , Ning Lixin , Molokeev Maxim S. , Chuang Yu‐Chun , Zhang Qinyuan , Poeppelmeier Kenneth R. , Xia Zhiguo
Published: June 2019

Establishing an effective design principle in solid‐state materials for a blue‐light‐excited Eu2+‐doped red‐emitting oxide‐based phosphors remains one of the significant challenges for white light‐emitting diodes (WLEDs). Selective occupation of Eu2+in inorganic polyhedra with small coordination numbers results in broad‐band red emission as a result of enhanced crystal‐field splitting of 5d levels. Rb3YSi2O7:Eu exhibits a broad emission band atλmax=622 nm under 450 nm excitation, and structural analysis and DFT calculations support the concept that Eu2+ions preferably occupy RbO6and YO6polyhedra and show the characteristic red emission band of Eu2+. The excellent thermal quenching resistance, high color‐rendering index Ra(93), and low CCT (4013 K) of the WLEDs clearly demonstrate that site engineering of rare‐earth phosphors is an effective strategy to target tailored optical performance.