bluuebunny/crossref_metadata_2025 huggingface dataset:
Research and Development of Oligonucleotides Targeting MicroRNAs (miRNAs)
Authors: Malinowska A. L. , Hall J.
Published: February 2019

MicroRNAs (miRNAs) are small, highly conserved, endogenous RNAs that regulate large parts of the gene expression in cells. Dysregulation of a miRNA's function, caused, for example, by mutations, loss of expression, disrupted maturation, or reduced stability etc., may cause or contribute to the progression of disease states. Oligonucleotides complementary to a miRNA (antimiRs) have been developed to bind and inhibit their function, both as tools and as potential therapeutics. Medicinal chemistry efforts designed to modify antimiRs so that they may be used in vivo have followed a similar path to those for antisense, splice-modulating and small interfering RNAs. Here we review some of the chemical modifications that have been employed in antimiRs and how some of these have advanced to clinical testing. We also describe how knowledge of the mechanisms of miRNA biogenesis and mRNA targeting is influencing the next generation of antimiR reagents.
Oligonucleotide Targeting of Long Non-coding RNAs
Authors: Blokhin I. , Khorkova O. , Hsiao J. , Wahlestedt C.
Published: February 2019

In recent years, it has been shown that the central dogma of molecular biology with an underlying “one gene–one protein” concept is no longer viable. Instead, the transcriptome is dominated by non-coding RNA transcripts. Several classes of non-coding RNAs, including ribosomal RNAs, transport RNAs, microRNAs, small nuclear RNAs and a few others have been relatively well characterized. At the same time, there is one family in the non-coding transcriptome, long non-coding RNAs (lncRNAs), which, despite being the most abundant, remains structurally and functionally mysterious. Initially considered to be transcriptional noise, lncRNAs have now come under intense scrutiny, and the number of papers on lncRNAs has grown exponentially. Due to their ability to interact with virtually all classes of biomolecules, lncRNAs appear to have unique and enormous functional potential. Such a broad action of lncRNAs promises potential therapeutic implications. It is challenging to target lncRNAs by traditional medicines, such as small molecules and antibodies, but oligonucleotide-based therapies, which have been considerably improved within the last two decades, may be a perfect match. Despite translational studies of lncRNAs being in their infancy, these approaches already appear to be of therapeutic value. Here we discuss basic biology and functions of lncRNAs as well as lncRNA-dependent mechanisms of pathogenesis. We also discuss oligonucleotide-based drugs as a tool to harness those mechanisms for therapeutic purposes.
Liver-targeted RNAi Therapeutics: Principles and Applications
Authors: Rajeev Kallanthottathil G. , Manoharan Muthiah
Published: February 2019

Although chemical modifications of the nucleic acid backbone, sugar, and base have imparted drug-like properties to small interfering RNA (siRNA), it was not until recently that systemic delivery at therapeutically acceptable doses was enabled. Use of ionizable lipid nanoparticles (iLNPs) and covalent conjugation to N-acetylgalactosamine (GalNAc) resulted in effective delivery of siRNAs to liver. Here, we discuss the development of these delivery technologies and describe how chemical modifications result in siRNAs that do not trigger the innate immune response and that are systemically stable. We highlight the findings from about 25 siRNA-based drugs targeting diseases originating from liver in various stages of clinical testing with a focus on several from Alnylam's clinical pipeline. In this pipeline, the clinically validated iLNP formulation by intravenous administration and GalNAc-conjugated delivery by subcutaneous administration make possible infrequent dosing of therapeutic siRNAs to several hitherto “undruggable” molecular targets, realizing the promise of RNA interference (RNAi)-based drugs to benefit patients.
Amperometric enzyme sensor for the rapid determination of histamine
Authors: Torre Ricarda , Costa-Rama Estefanía , Lopes Paula , Nouws Henri P. A. , Delerue-Matos Cristina
Published: February 2019

A simple sensor combining screen-printed carbon electrodes and diamine oxidase is developed for histamine detection.
A hydrogel sensor-based microfluidic platform for the quantitative and multiplexed detection of fertility markers for point-of-care immunoassays
Authors: Kalme Satish , Kandaswamy Srinivasan , Chandrasekharmath Anusha , Katiyar Reeta , Rajamanickam Gokul Prasath , Kumar Suraj , Dendukuri Dhananjaya
Published: February 2019

We report a new point-of-care, multiplexed immunoassay platform based on 3D porous hydrogel particle sensors embedded into a plastic microfluidic device.
Double graphitic-N doping for enhanced catalytic oxidation activity of carbocatalysts
Authors: Hou Meiling , Zhang Xin , Yuan Shandong , Cen Wanglai
Published: February 2019

Double-GrN remarkably enhanced the catalytic efficiency for O2 dissociation reactions and accelerates the generation of highly chemically reactive oxygen functional groups. The promotion effect is ascribed to the reduction of the work function of carbocatalysts due to N doping, which facilitates the transfer of electrons from carbocatalysts to the adsorbed O2 molecules for their activation.
Negative thermal expansion in cubic FeFe(CN)6 Prussian blue analogues
Authors: Shi Naike , Gao Qilong , Sanson Andrea , Li Qiang , Fan Longlong , Ren Yang , Olivi Luca , Chen Jun , Xing Xianran
Published: February 2019

A new isotropic negative thermal expansion compound of FeFe(CN)6 has been found, in which the transverse vibrations of N atoms dominate in its NTE behavior.
Cyclodextrin-/photoisomerization-modulated assembly and disassembly of an azobenzene-grafted polyoxometalate cluster
Authors: Li Hongbo , Jiang Fengrui , Zhang Guohua , Li Bao , Wu Lixin
Published: February 2019

An organically grafted polyoxometalate cluster was synthesized for transformable assemblies, and the assembly/disassembly cycles were achieved through multiple stimuli–responses.
Comparative oral and intravenous pharmacokinetics of phlorizin in rats having type 2 diabetes and in normal rats based on phase II metabolism
Authors: Wang Zhanguo , Gao Ziyang , Wang Anqi , Jia Lan , Zhang Xiaoyu , Fang Ming , Yi Kang , Li Qijuan , Hu Huiling
Published: February 2019

Phlorizin (PHZ), a type of dihydrochalcone widely found in Rosaceae such as apples, is the first compound discovered as a sodium-glucose cotransporter (SGLT) inhibitor.
Effects on longevity extension and mechanism of action of carnosic acid in Caenorhabditis elegans
Authors: Lin Chunxiu , Zhang Xiaoying , Xiao Jie , Zhong Qiqi , Kuang Yong , Cao Yong , Chen Yunjiao
Published: February 2019

The study offers methods and models for elucidating healthspan promotion and mechanism, valuable for studies of other naturally active compounds.
Recovering cellulase and increasing glucose yield during lignocellulosic hydrolysis using lignin-MPEG with a sensitive pH response
Authors: Cai Cheng , Bao Yu , Zhan Xuejuan , Lin Xuliang , Lou Hongming , Pang Yuxia , Qian Yong , Qiu Xueqing
Published: February 2019

Recovering cellulase and increasing glucose yield during lignocellulosic hydrolysis using lignin-MPEG with a sensitive pH response.
Dual inhibitors of LSD1 and spermine oxidase
Authors: Holshouser Steven , Dunworth Matthew , Murray-Stewart Tracy , Peterson Yuri K. , Burger Pieter , Kirkpatrick Joy , Chen Huan-Huan , Casero Robert A. , Woster Patrick M.
Published: February 2019

Dual inhibitors of LSD1 and SMOX, with no activity against N1-acetylpolyamine oxidase (PAOX).
Strontium confinement in polyacrylic acid brushes: a soft nanoarchitectonics approach for the design of titania coatings with enhanced osseointegration
Authors: Gregurec Danijela , Politakos Nikolaos , Yate Luis , Moya Sergio E.
Published: February 2019

Polyacrylic acid (PAA) brushes synthesized by reversible addition fragment chain transfer (RAFT) polymerization on titania (TiO2) surfaces were applied for the surface confinement and slow delivery of strontium (Sr2+) ions during the osseointegration process on TiO2surfaces.
Water-soluble binary and ternary palladium(ıı) complexes containing amino acids and intercalating ligands: synthesis, characterization, biomolecular interactions and cytotoxicities
Authors: İnci Duygu , Aydın Rahmiye , Vatan Özgür , Şahin Onur , Çinkılıç Nilüfer
Published: February 2019

Novel water soluble palladium(ii) complexes have been synthesized and characterized. Moreover, the cytotoxicities of these complexes against different human tumor and healthy cell lines were investigated by the XTT assay.
Formation of small clusters of NaCl dihydrate in the gas phase
Authors: García Juan-José , Hernández-Esparza Raymundo , Vargas Rubicelia , Tiznado William , Garza Jorge
Published: February 2019

Sodium chloride dihydrates form cuboid structures in initial stages of nucleation, preserving the NaCl interaction.
Recent advances in the synthesis of C2-spiropseudoindoxyls
Authors: Ji Yanling , He Xianghong , Peng Cheng , Huang Wei
Published: February 2019

This review summarizes the recent development of novel approaches to construct structurally unique oxindoles featuring a spirocycle at the C2 position.
A novel strategy to purify conductive polymer particles
Authors: Spence Daron , Polizos Georgios , Joshi Pooran , Sharma Jaswinder
Published: February 2019

A novel strategy to purify conductive polymer nanoparticles is presented.
The application of a non-doped composite hole transport layer of [MoO3/CBP]n with multi-periodic structure for high power efficiency organic light-emitting diodes
Authors: Gao Zhixiang , Feng Zilong , Chen Weihua , Qu Wenshan , Ao Wei , Yang Tingting , Li Jiangang , Gao Feng
Published: February 2019

A non-doped multi-periodic structure of composite hole transport layer of [MoO3/CBP]n was applied to organic light-emitting diodes.
Preparation of gemini surfactant/graphene oxide composites and their superior performance for Congo red adsorption
Authors: He Shuai , Liu Xingli , Yan Ping , Wang Anqi , Su Jinzhu , Su Xin
Published: February 2019

Gemini surfactant/GO composites were prepared for the removal of Congo red dye, and show excellent adsorption capacities and reusabilities.
Free fatty acids esterification catalyzed by acid Faujasite type zeolite
Authors: Dal Pozzo Daniel Marcos , Azevedo dos Santos José Airton , Júnior Edward Seabra , Santos Reginaldo Ferreira , Feiden Armin , Melegari de Souza Samuel Nelson , Burgardt Ismael
Published: February 2019

FFA esterification pre-treatment catalyzed by a Faujasite type zeolite.
Sponge-like N-doped carbon materials with Co-based nanoparticles derived from biomass as highly efficient electrocatalysts for the oxygen reduction reaction in alkaline media
Authors: Lu Guolong , Li Zhiyuan , Fan Wenxuan , Wang Mi , Yang Shuchen , Li Jiayi , Chang Zhiyong , Sun Hang , Liang Song , Liu Zhenning
Published: February 2019

Sponge-like N-doped carbon materials with Co-based nanoparticles derived from biomass as high efficient electrocatalysts for oxygen reduction reaction.
Nitrogen-decorated, porous carbons derived from waste cow manure as efficient catalysts for the selective capture and conversion of CO2
Authors: Kong Weiping , Liu Jing
Published: February 2019

Nitrogen-doped, hierarchically porous carbons were prepared by the activation of waste cow manure at 600 °C, which acted as efficient catalysts for the highly selective capture and conversion of CO2into valuable chemicals.
Poly(ethylene glycol) brush-b-poly(N-vinylpyrrolidone)-based double hydrophilic block copolymer particles crosslinked via crystalline α-cyclodextrin domains
Authors: Al Nakeeb Noah , Kochovski Zdravko , Li Tingting , Zhang Youjia , Lu Yan , Schmidt Bernhard V. K. J.
Published: February 2019

Self-assembly of the double hydrophilic block copolymer poly(N-vinylpyrrolidone)-b-poly(oligoethylene glycol methacrylate) and supramolecular crosslinking via α-cyclodextrin in water is presented.
Construction of unique heterogeneous cobalt–manganese oxide porous microspheres for the assembly of long-cycle and high-rate lithium ion battery anodes
Authors: Wu Bin , Xie Yue , Meng Yaqin , Qian Cheng , Chen Yingying , Yuan Aihua , Guo Xingmei , Yang Hongxun , Wan Shijian , Lin Shengling
Published: February 2019

Porous (Co, Mn)(Co, Mn)2O4-based microspheres (CM-11-Ms) and core–shell microspheres (CM-11-CSMs) were firstly synthesized via controlled pyrolysis of CoMn-precursor microspheres at different temperatures under nitrogen, exhibiting advanced lithium storage capacities.
Comment on “Bi-functional Li2B12H12 for energy storage and conversion applications: solid-state electrolyte and luminescent down-conversion dye” by J. A. Teprovich Jr, H. Colón-Mercado, A. L. Washington II, P. A. Ward, S. Greenway, D. M. Missimer, H. Hartman, J. Velten, J. H. Christian and R. Zidan, J. Mater. Chem. A, 2015, 3, 22853
Authors: Paskevicius M. , Jakobsen A. S. , Bregnhøj M. , Hansen B. R. S. , Møller K. T. , Ogilby P. R. , Jensen T. R.
Published: February 2019

Assessment of metal closo-borane photoluminescence.
Visible light-driven simultaneous H2 production by water splitting coupled with selective oxidation of HMF to DFF catalyzed by porous carbon nitride
Authors: Battula Venugopala Rao , Jaryal Arpna , Kailasam Kamalakannan
Published: February 2019

Simultaneous H2 evolution and biomass valorization under visible light. Simultaneous production of H2 at a rate of 36 μmol h−1 m−2 and 38.4% DFF yield (>99% selectivity) after 48 h.
Temperature- and pressure-dependent studies of a highly flexible and compressible perovskite-like cadmium dicyanamide framework templated with protonated tetrapropylamine
Authors: Mączka Mirosław , Ptak Maciej , Gągor Anna , Sieradzki Adam , Peksa Paulina , Usevicius Gediminas , Simenas Mantas , Leite Fabio Furtado , Paraguassu Waldeci
Published: February 2019

Perovskite-like [TPrA][Cd(dca)3] undergoes four temperature-induced phase transitions associated with dielectric anomalies and one pressure-induced phase transition into a monoclinic phase.
Zwitterionic and cationic half-sandwich iridium(iii) ruthenium(ii) complexes bearing sulfonate groups: synthesis, characterization and their different biological activities
Authors: Yang Yanjing , Ge Xingxing , Guo Lihua , Zhu Teng , Tian Zhenzhen , Zhang Hairong , Du Qing , Peng Hongwei , Ma Wenli , Liu Zhe
Published: February 2019

This work is the first demonstration of the different biological activity between zwitterionic and cationic complexes.
Novel carbohydrate modified berberine derivatives: synthesis andin vitroanti-diabetic investigation
Authors: Han Liwen , Sheng Wenlong , Li Xiaobin , Sik Attila , Lin Houwen , Liu Kechun , Wang Lizhen
Published: February 2019

Berberine is a bioactive alkaloid used in Chinese medicine and has numerous positive effects on biological systems.
Synthesis and characterization of potential stereoisomeric and degradation impurities of ulipristal acetate
Authors: Xu Pengfei , Luan Hongyu , Yu Bin , Tu Yongrui , Sun Yongqiang , Chen Wei , Xu Xi , Ge Raoling , Wang Jubo , Li Zhiyu , Bian Jinlei
Published: February 2019

Potential stereoisomeric and degradation impurities of UPA has been synthesized through practical approaches which would be valuable for the quality control of UPA.
In situ structural evolution of a nickel boride catalyst: synergistic geometric and electronic optimization for the oxygen evolution reaction
Authors: Li Jihong , Chen Hui , Liu Yipu , Gao Ruiqin , Zou Xiaoxin
Published: February 2019

A boronized nickel plate shows surface structural evolution and activity enhancement during the OER due to synergistic geometric and electronic effects, and shows good catalytic stability for over 1500 hours.
SAA1 gene polymorphisms in osteoporosis patients
Authors: Zhou Xindie , Li Jin , Jiang Lifeng , Zhou Dong , Wu Lidong , Huang Yong , Xu Nanwei
Published: February 2019

Background: Serum amyloid A (SAA1) is an apolipoprotein that maintains glucose and lipid homeostasis. Its polymorphisms are associated with risks of myocardial infarction and coronary artery disease (CAD). Methods: However, little is known about the associations of these polymorphisms with susceptibility to osteoporosis, which we evaluated in this hospital-based case–control study involving 300 osteoporosis patients and 350 controls. Three single-nucleotide polymorphisms (SNPs) (rs183978373, rs12218, and rs10832915) were genotyped using MALDI TOF MS. Results: There were no differences in the rs183978373 and rs12218 polymorphisms between the osteoporosis group and controls. The SAA1 gene rs10832915 polymorphism increased the risk of osteoporosis in our Chinese population. The genotypes of the rs10832915 polymorphism were not significantly associated with clinical parameters (age, body mass index (BMI), high- and low-density lipoprotein (LDL), total cholesterol (TC), and T-score). Haplotype analysis revealed that the ATT haplotype had a significant correlation with a decreased risk of osteoporosis. Conclusion: In conclusion, the SAA1 rs10832915 polymorphism and its haplotypes are associated with osteoporosis, but this finding should be confirmed in large well-designed studies.
What Our Hands Tell Us: A Two-Year Follow-Up Investigating Outcomes in Subgroups of Children With Language Delay
Authors: O'Neill Hilary , Murphy Carol-Anne , Chiat Shula
Published: February 2019

Purpose

This study followed up children identified with expressive language delay (ELD) or receptive/expressive language delay (R/ELD) at 2 years of age, Time 1 (T1), in order to identify their language profiles at 4–5 years, Time 2 (T2), and explore relationships to T1 language, gesture use, and symbolic comprehension.

Method

Nineteen of 22 children were seen at follow-up (9 of 10 from R/ELD group, 10 of 12 from ELD group). T1 measures assessed receptive and expressive language, gesture use, and symbolic comprehension. At T2, we assessed receptive and expressive language, sentence repetition, and expressive phonology.

Results

Outcomes for the R/ELD group were significantly poorer, with all children continuing to have delay in receptive and/or expressive language compared to just 20% of the ELD group. Expressive phonology delay was common in both groups. T1 receptive language showed the most pervasive correlations with T2 language measures, but categorical performance on all three T1 measures correctly predicted language outcomes in 16–17 of the 19 children.

Conclusion

Findings add to evidence that receptive language is a strong predictor of outcomes. Gesture use and symbolic comprehension are also strong predictors and clinically valuable as part of play-based assessments with implications for theoretical understanding and intervention planning.
Building a Successful Voice Telepractice Program
Authors: Grillo Elizabeth U.
Published: February 2019

Purpose

Telepractice offers prevention, assessment, treatment, and consultation at a distance. This article provides an overview of telepractice with specific considerations and examples related to voice across licensure requirements, state and federal laws, reimbursement, documentation, and telepractice methods.

Conclusion

As technology continues to advance and as client demand for telepractice services increases, practitioners need to create successful telepractice programs.

Supplemental Material

https://doi.org/10.23641/asha.7645286
Benchmarking of the BITalino biomedical toolkit against an established gold standard
Authors: Batista Diana , Plácido da Silva Hugo , Fred Ana , Moreira Carlos , Reis Margarida , Ferreira Hugo Alexandre
Published: February 2019

The low‐cost multimodal platform BITalino is being increasingly used for educational and research purposes. However, there is still a lack of well‐structured work comparing data acquired by this toolkit against a reference device, using established experimental protocols. This work intends to fill the said gap by benchmarking the performance of BITalino against the BioPac MP35 Student Lab Pro device. This work followed a methodical experimental protocol to acquire data from the two devices simultaneously. Four physiological signals were acquired: electrocardiography, electromyography, electrodermal activity and electroencephalography. Root mean square error and coefficient of determination were computed to analyse differences between BITalino and BioPac. Electrodermal activity signals were very similar for the two devices, even without applying any major signal processing techniques. For electrocardiography, a simple morphological comparison also revealed high similarity between devices, and this similarity increased after a common segmentation procedure was followed. Regarding electromyography and electroencephalography data, the approach consisted of comparing features extracted using common post‐processing methods. The differences between BITalino and BioPac were again small. Overall, the results presented here show a close similarity between data acquired by the BITalino and by the reference device. This is an important validation step for all researchers working with this multimodal platform.
Network analysis through the use of joint‐distribution entropy on EEG recordings of MCI patients during a visual short‐term memory binding task
Authors: Josefsson Alexandra , Ibáñez Agustín , Parra Mario , Escudero Javier
Published: February 2019

The early diagnosis of Alzheimer's disease (AD) is particularly challenging. Mild cognitive impairment (MCI) has been linked to AD and electroencephalogram (EEG) recordings are able to measure brain activity directly with high temporal resolution. In this context, with appropriate processing, the EEG recordings can be used to construct a graph representative of brain functional connectivity. This work studies a functional network created from a non‐linear measure of coupling of beta‐filtered EEG recordings during a short‐term memory binding task. It shows that the values of the small‐world characteristic and eccentricity are, respectively, lower and higher in MCI patients than in controls. The results show how MCI leads to EEG functional connectivity changes. They expect that the network differences between MCIs and control subjects could be used to gain insight into the early stages of AD.
Fault‐tolerant control of DSBLDC motor drive under open‐circuit faults
Authors: Zhang Jian , Zhang Zhuoran , Yu Li , Bian Zhangming
Published: February 2019

Doubly salient brushless dc (DSBLDC) motor drive system has attracted increasing attention due to the rugged rotor structure, brushless operation and low cost. The switch open‐circuit (OC) fault increases the torque ripple and decreases the maximal output power of DSBLDC motor drive system. A fault‐tolerance control strategy for switch OC circuit is proposed in this study. The back electromotive force (BEMF) current would occur in a pulse‐width modulation (PWM) pattern. It severely degrades the proposed method's fault‐tolerant performance. So the cause of the BEMF current is analysed and BEMF current is suppressed by specific PWM pattern. Finally, the fault‐tolerance control strategy is verified by experiment results and the selection PWM pattern is proved to be correct and practical.
The HyEnD stern hybrid sounding rocket project
Authors: Kobald M. , Schmierer C. , Fischer U. , Tomilin K. , Petrarolo A. , Rehberger M.
Published: February 2019

The student team Hybrid Engine Development (HyEnD) of the University of Stuttgart is taking part with the Institute of Space Systems (IRS) in the DLR educational program STERN (Studentische Experimentalraketen). This program supports students at German universities to design, build, and launch an experimental rocket within a 3-year project time frame. HyEnD is developing a hybrid rocket called HEROS (Hybrid Experimental Rocket Stuttgart) with a design thrust of 10 kN, a total impulse of over 100 kN·s, and an expected liftoff weight up to 175 kg. HEROS is planned to be launched in October 2015 from Esrange in Sweden to an expected flight altitude of 40 to 50 km. The current altitude record for amateur rockets in Europe is at approximately 21 km. The propulsion system of HEROS is called HyRES (Hybrid Rocket Engine Stuttgart) and uses a paraffin-based solid fuel and nitrous oxide (N2O) as a liquid oxidizer. The development and the test campaign of HyRES is described in detail. The main goals of the test campaign are to achieve a combustion efficiency higher than 90% and provide stable operation with low combustion chamber pressure fluctuations. The successful design and testing of the HyRES engine was enabled by the evaluation and characterization of a small-scale demonstrator engine. The 500-newton hybrid rocket engine, called MIRAS (MIcro RAkete Stuttgart), has also been developed in the course of the STERN project as a technology demonstrator. During this test campaign, a ballistic characterization of paraffin-based hybrid rocket fuels with different additives in combination with N2O and a performance evaluation were carried out. A wide range of operating conditions, fuel compositions, injector geometries, and engine configurations were evaluated with this engine. Effects of different injector geometries and postcombustion chamber designs on the engine performance were analyzed. Additionally, the appearance of combustion instabilities under certain conditions, their effects, and possible mitigation techniques were also investigated. Concluding, the development and construction of an advanced, lightweight hybrid sounding rocket for the given requirements and budget within the DLR STERN program are described herein. The most important parts include a high thrust hybrid rocket engine, the development of a light weight oxidizer tank, pyrotechnical valves, carbon fiber rocket structure, recovery systems, and onboard electronics.
Green gelled propellant highly throtteable rocket motor and gas generator technology: status and application
Authors: Caldas Pinto P. , Ciezki H.K. , Naumann K.W. , Ramsel J. , Kröger P. , Niedermaier H. , Negri M. , Scheutzow S. , Thumann A. , Kurth G.
Published: February 2019

Work on gel propulsion began in Germany in 1999. The German Gel Propulsion Technology (GGPT) Program started in 2001 from a white sheet of paper, proposed by the DLR Institute of Space Propulsion, Bayern-Chemie (BC), and the Fraunhofer Institute of Chemical Technology. Aim of the first phase was to develop the technology needed to build a rocket motor burning gelled propellants and to demonstrate its operability by a free flight within significantly less than a decade. The research and development activities were guided by a suitable principal concept for a gelled propellant rocket motor (GRM). Based on theoretical considerations (regarding functional aspects) and experimental pre-tests (propellant development, gelation, rheology, spraying, ignition, and combustion), a motor concept was pre-selected and the motor developed. The identified requirements were proven in December 2009 by two successful demonstration flights. The achieved know-how from basic research and technology (R+T) development has been consolidated in an application-oriented way on component level up to motor development. Within this scope, also, the goal of an effective control of the thrust by throttling the propellant mass flow rate (PMFR) while maintaining an optimum combustion chamber (CC) pressure could be achieved. This publication describes briefly several major advances in the development of the gel propulsion technology in Germany from rheology to combustor development to the thrust and pressure controller of a GRM.
Consequences of modeling demands on numerical rocket thrust chamber flow simulation tools
Authors: Knab O. , Riedmann H. , Ivancic B. , Höglauer C. , Frey M. , Aichner T.
Published: February 2019

Numerical simulation of liquid rocket thrust chamber flows is a challenging task which requires a comprehensive tool validation strategy encompassing laboratory- to full-scale test cases. While the former are widely used as the first step to verify advanced numerical schemes and thermochemical models, the latter can often no more be simulated in a reasonable time frame due to the extreme computational effort necessitated by the enlarged dimensions and configurational changes. Conclusions drawn from tools with such limitations are only of little help for a thrust chamber designer and, hence, ill-posed to adequately tackle the simulation challenges of such a device. This paper discusses the modeling demands for numerical thrust chamber flow simulation tools and outlines the indispensable validation approach from laboratory- via subto full-scale configurations using consistent model features throughout the test cases. Consequences of this obligation are exposed to drive the tool setup. Exemplarily, the Airbus DS thrust chamber flow simulation philosophy is presented.
Ballistic phase performance model for cold gas attitude control in cryogenic upper stages
Authors: Werner M. , Kottmeier S. , Bruns T. , Korus N.
Published: February 2019

During the ballistic phase of a cryogenic upper stage, attitude and orbit control are usually performed by a cold gas thruster system. Since the thruster inlet pressure is driven by the propellant tank ullage conditions, a sufficient pressure regeneration rate has to be assured to compensate the pressure decrease during thruster activation. The coupling between the thruster activation sequence, stage kinematics, and thermal environment is essential for the performance prediction of cold gas systems. An iteration loop using a statistical model considering the thruster activation sequence is applied. For detailed final analysis, an EcosimPro model is used, including three-dimensional (3D) CFD (computational fluid dynamics) sloshing analysis and all relevant boundary conditions.
Hot-fire testing of liquid oxygen/hydrogen single coaxial injector at high-pressure conditions with optical diagnostics
Authors: Suslov D.I. , Hardi J.S. , Knapp B. , Oschwald M.
Published: February 2019

Injector behavior is of utmost importance for the performance and stability of liquid rocket engines (LREs). A major problem is getting a highly efficient homogeneous mixture and effective chemical reaction of fuels at minimum chamber length. Despite substantial progress in numerical simulations, a need for experimental data at representative conditions for development and validation of numerical design tools still exists. Therefore, in the framework of the DLR-project “ProTau,” the authors have performed tests to create an extended data base for numerical tool validation for high-pressure liquid oxygen (LOx) / hydrogen combustion. During the experimental investigations, a windowed DLR subscale thrust chamber model “C” (designated BKC) has been operated over a broad range of conditions at reduced pressures of approximately 0.8 (4 MPa), 1 (5 MPa), and 1.2 (6 MPa) with respect to the thermodynamic critical pressure of oxygen. Liquid oxygen and gaseous hydrogen (GH2) have been injected through a single coaxial injector element at temperatures of ~ 120 and ~ 130 K, respectively. High-speed optical diagnostics have been implemented, including imaging of OH* emission and shadowgraph imaging at frequencies from 8 up to 10 kHz to visualize the flow field.
Measuring the phase between fluctuating pressure and flame radiation intensity in a cylindrical combustion chamber
Authors: Gröning S. , Hardi J.S. , Suslov D. , Oschwald M.
Published: February 2019

The energy transfer from the heat release of the combustion to the acoustic pressure oscillations is the driving element of combustion instabilities. This energy transfer is described by the Rayleigh criterion and depends on the phase shift between the pressure and heat release rate oscillations. A research rocket engine combustor, operated with the propellant combination hydrogen/oxygen, was equipped with dynamic pressure sensors and fibre optical probes to measure the flame radiation. This setup has been used for a phase shift analysis study which showed that unstable operation is characterized by a phase shift leading to an energy transfer from the heat release to the acoustic pressure oscillations.
LOx/ethanol gas generator: investigation and development
Authors: Hahn R.H.S. , Nascimento L.B. , Almeida D.S.
Published: February 2019

This paper presents preliminary experimental results of a gas generator (GG) developed for research to determine the burning characteristics in mixture ratios below the stoichiometric and the validation of the chemical equilibrium software, as well as performance calculations, with own developed software used specifically in the design of this model of GG. For this work, tests were carried out at pressures below nominal operation point for an initial investigation of combustion behavior in low mixture ratio. The results show the possibility to a new analysis method which leads to development of numerical tools to investigate its behavior.
Parametrical study on side load generation in subscale rocket nozzles
Authors: Stark R. , Génin C.
Published: February 2019

The flow separation within convergent–divergent rocket engine nozzles induces undesired side loads. As the flow separation cannot be avoided during startup and shutdown processes of the engine, the understanding of the resulting side loads is of crucial interest. To develop and validate side load models, an experimental parametrical study was conducted. The parameters of interest were the length of the separated backflow region, the wall contour angle, and the total pressure gradient during startup and shutdown processes. For this reason, three subscale models were designed and tested in five configurations. As the main side load driver, a comparably slow moving separation front, passing a long and narrow backflow region, could be identified.
Design and tool anchoring for a 120-kilonewton expander cycle rocket engine liquid oxygen turbopump
Authors: Souverein L. , Maeding C. , Aichner T. , Ivancic B. , Wagner A. , Frey M.
Published: February 2019

As part of a German nationally funded research programme “TARES,” a turbopump initiative has been started in recent years within Airbus DS GmbH. The aim of this study is to design a liquid oxygen (LOx) turbopump assembly (LOx-TPA) for a 120-kilonewton thrust class expander cycle rocket engine. To realize this objective, Airbus DS GmbH builds on in-house heritage, notably the turbopumps of the P111 and the H20 staged combustion engines. This experience serves as input for the design of the 120-kilonewton LOx turbopump. The current paper details the fluidic design of the turbopump, including the design philosophy and the anchoring on the heritage hardware. Discussed are the pump and turbine predesign starting from the configuration trade-off, the preliminary design, the flow path and blade design, and the design of inlet/outlet and the volute. Finally, the performance (nominal and off-design) is characterized by means of three-dimensional (3D) computational fluid dynamics (CFD) simulations.
Experimental investigation of spray combustion regimes in aeroengine combustors
Authors: Vicentini M. , Lecourt R. , Rouzaud O. , Bodoc V. , Simonin O.
Published: February 2019

At ONERA Fauga-Mauzac center, a new air-breathing propulsion test setup, Prométhée-LACOM, has been recently developed. In this paper, both nonreacting and reacting two-phase flows (nonpremixed spray) were investigated. Under reactive conditions, simultaneous OH-PLIF (planar laser-induced fluorescence) and Mie scattering imaging were implemented in order to characterize the spray flame structure. The different behaviors observed in this study seem to support the existence of spray combustion regimes. Moreover, statistical analysis was performed on the spatial distribution of droplets and indicated that the center-to-center interdroplet distance (nearest neighbor) could be described by means of a perfectly random distribution.
Exploratory investigations on metal-based fuels for air-breathing propulsion
Authors: Maggi F. , Colciago S. , Paravan C. , Dossi S. , Galfetti L.
Published: February 2019

Air-breathing solid fueled propulsion devices represent rugged, cheap, and rather simple options, out of the ramjet (RJ) category, which can contribute to volume containment and structural weight reduction. In the case of a ducted rocket, a fuel-rich propellant is burned in a primary combustion chamber and part of the oxidizer is taken from the atmosphere to complete the combustion inside a ram burner before exhaust. The use of metal additives contributes to the development of high-energy density materials, featuring better volumetric specific impulse. Metal powders are characterized by high energetic content per unit volume but can feature issues of difficult ignition, generation of condensed combustion products (CCPs), and incomplete combustion. The present work discusses a series of exploratory investigations on aluminum-based pyrolants. Thermochemical analyses, calorimetric investigations, and combustion tests will be considered, looking at improvements introduced by metal addition.
The numerical simulation techniques research and preliminary experimental validation of the start characteristics for a two-dimensional hypersonic inlet
Authors: Yu A. , Yang D. , Wu J. , Ni H. , Le J.
Published: February 2019

The paper presents the research of the numerical simulation techniques and the preliminary experimental validation on the start characteristics for a typical two-dimensional (2D) hypersonic inlet. In order to obtain the start and unstart hysteresis loop, numerical simulations methods using the incoming flow field, the zero-velocity flow field, and the latest convergent flow field as the initialized flow field separately are adopted to calculate the inlet start characteristics until the flow fields converge. The calculation software is AHL3D, a parallel computational fluid software self-developed by CARDC. The numerical methods also include the method from unstart flow field to start one with Mach-numbers gradually increasing till the inlet is start and the method from start flow field to unstart one with Mach-numbers decreasing till the inlet is unstart. According to the comparison with different initialized flow field and with different step-size of Mach-number, the inlet start characteristics are obtained and the numerical techniques are analyzed. Based on the comparison and the analysis, it is suggested that the numerical techniques of inlet start characteristics should use the zero-initialized flow field with one step to the final Mach-numbers to predict the minimal self-start Mach-number of the inlet and use the incoming flow-initialized flow field to predict the minimum start Mach-number. The results show that the numerical techniques are high-efficient and easily operational. To verify the effect of the numerical techniques, wind tunnel tests are arranged to research the start characteristics of a typical 2D hypersonic inlet. The preliminary experimental result shows that the numerical techniques of predicting inlet start characteristics are consistent with the experiments very well, which means that the application of the numerical techniques can be further carried out for such hypersonic inlets as mentioned in the current paper.
Microvortex generator for scramjet inlet application
Authors: Idris A.C. , Saad M.R. , Kontis K.
Published: February 2019

Global measurement approach in characterizing a generic scramjet inlet has enabled the investigation of various flow phenomena typically occurred on an inlet to be investigated further. This paper examines the effectiveness of microvortex generator (MVG) array in suppressing boundary layer separations on such an inlet. Global measurement of pressure and temperature were employed to visualize vortex pairs emanating from the MVG. The global pressure map showed the benefit of lower reattachment peak pressure that usually accompanies the large separation bubble at a scramjet inlet throat.
Control of the surface electron-beam alloying process by vibration monitoring
Authors: Fedorov Sergey V. , Kozochkin Mikhail P. , Stebulyanin Mikhail M.
Published: February 2019

The experimental results prove the ability to realize technology of chemical heat treatment of some materials by surface alloying using a wide-aperture low-energy high-current electron beam. Doped hardened layers were produced due to initiating exothermic chemical reactions between the base and the thin film covered on it. Nevertheless, it is quite difficult to control the process of surface electron-beam alloying due to the significant variation in the parameters of the microsecond electron beam pulse and the instability of its interaction with the processed material. It leads to significant random changes that occur spontaneously, regardless of the control system. In this situation, it is proposed to use the method based on monitoring of oscillations and acoustic emission, which has long proved to be an effective tool in the study of phase transformations and plastic deformation. The appearance of a process with high vibroacoustic activity under irradiation of plates made of pre-nitrated steel 08Cr17Ti with a deposited film Nb70Hf22Ti8in the range of 11–22 kHz 10 ms after the electronic pulse was experimentally shown on this background. The source of this vibroacoustic signal is a change in the microstructure of the alloy, including the appearance of a martensitic component in the near-surface layer of the sample caused by the formation of nitride based on niobium. Tracking changes in the effective value of the vibroacoustic signal allow choosing the rational modes of irradiation with electron-beam surface alloying, involving the supply of maximum power, limited by the possibility of evaporation of the film with alloying components.
Improvement reliability of cutting ceramic through use of damping system and nanostructured multilayered composite coatings
Authors: Vereschaka Alexey , Mokritskii Boris , Krapostin Alexey , Sitnikov Nikolay , Oganyan Gaik
Published: February 2019

This paper considers new avenues of improving the efficiency of machining hardened steels using damping devices and nanostructured multilayered composite coatings deposited on ceramic cutting tools with innovative arc-PVD processes with filtration of vapor-ion flow. A developed technology allows reducing peak stresses arising during cutting-in and providing improved reliability of ceramic tools. It is observed that the formation of modifying coatings on an edge ceramic tool in machining of hardened steels with HRC > 50 under the conditions of damping can reduce the coefficient of tool failure variation down to 0.3, and that improves the ability to predict failure of ceramic tools and allows recommending ceramic tools for the use in automated production.
Contact Lenses in the Management of Corneal Dystrophies
Authors: Farooq Asim Visal , Colby Kathryn
Published: February 2019

Among the group of diseases comprising corneal dystrophies, there are a number for which contact lenses may be considered. For example, soft contact lenses may be beneficial in the management of recurrent corneal erosions and advanced bullous keratopathy and may lead to disease attenuation in some conditions. They also may be used in conjunction with surgical procedures to promote tissue healing and patient comfort in the postoperative period. Rigid contact lenses may be beneficial in the setting of irregular astigmatism. The present review of the literature will discuss the use of contact lenses in the management of corneal dystrophies.
Trabekulektomie mit Kollagen-Matrix-Implantat als Bevacizumabdepot: klinische Ergebnisse zur Effektivität und Sicherheit
Authors: Lommatzsch Claudia , Heinz Carsten , Rothaus Kai , Koch Jörg M.
Published: February 2019

Hintergrund Die Trabekulektomie zur operativen Augeninnendrucksenkung ist ein etabliertes Verfahren, das seine Limitationen vor allem in der postoperativen Wundheilung hat. Verschiedene Antimetabolite werden bereits standardmäßig zur Vermeidung der postoperativen subkonjunktivalen Vernarbungsreaktion verwendet. In der vorliegenden Arbeit wurde verglichen, ob die Kombination eines Ologen-Implantates mit Bevacizumab die Erfolgsrate und/oder Komplikationsrate im Rahmen einer Trabekulektomie verändern kann.

Methoden In einer monozentrischen retrospektiven Studie wurden 3 Patientengruppen ausgewertet, bei denen eine Trabekulektomie (TE) mit Mitomycin C (MMC) erfolgte, entweder solitär (Gruppe 1) oder in Kombination mit einem Ologen-Implantat (Gruppe 2) oder mit einem Ologen-Implantat mit Eingabe von Bevacizumab (Gruppe 3). Ausgewertet wurden die Erfolgs- und Misserfolgsrate, der Tensioverlauf, postoperative Komplikationen und die Notwendigkeit von postoperativen erneuten Eingriffen zur Druckregulation. Die Nachbeobachtung betrug für alle Augen 12 Monate.

Ergebnisse Insgesamt wurden 130 Augen von 130 Patienten im mittleren Alter 67,74 ± 12,16 Jahren operiert. Präoperativ lag die Anzahl der lokal applizierten drucksenkenden Substanzen bei 2,89 ± 0,98 und der Augeninnendruck (IOD) bei 21,74 ± 5,49 mmHg. Zwölf Monate postoperativ lag die mittlere Tensio bei 13,14 ± 3,71 mmHg. Die höchste absolute Erfolgsrate (= IOD ≤ 15 mmHg ohne antiglaukomatöse Medikation) konnte in der Gruppe erreicht werden, die ausschließlich eine Goniotrepanation + MMC erhalten haben (72,5%), gefolgt von der Gruppe mit Ologen (67,5%) und Ologen + Bevacizumab (63,6%). Die höchste Misserfolgsrate (= IOD > 15 mmHg) hatte die Ologen-Bevacizumab-Gruppe (17,3%), gefolgt von der reinen Ologen-Gruppe mit 22,5% und der reinen Trabekulektomiegruppe (12,3%). Sowohl bei der Erfolgs- als auch der Misserfolgsrate ergab sich jedoch kein signifikanter Unterschied. In keiner Gruppe traten schwerwiegende intra- oder postoperative Komplikationen auf. Die Anzahl der Notwendigkeit einer Lockerung des Traktionsfadens war in der alleinigen Ologen-Gruppe signifikant niedriger (p = 0,02). Im Weiteren gab es keinen signifikanten Unterschied zwischen den Gruppen im Hinblick auf Folgeeingriffe.

Schlussfolgerung Die Verwendung von Ologen als Medikamentendepot für Bevacizumab im Rahmen einer TE mit MMC ist eine sichere und effektive operative Methode ohne erhöhtes Komplikationspotenzial im Vergleich zu einer reinen TE mit MMC oder einer TE mit MMC und Ologen-Implantat. Es zeigt sich im postoperativen Verlauf nach 12 Monaten jedoch kein signifikanter Vorteil gegenüber den anderen Gruppen.