bluuebunny/crossref_metadata_2025 huggingface dataset:
A Circulating miRNA Signature for Stratification of Breast Lesions among Women with Abnormal Screening Mammograms
Authors: Loke Sau Yeen , Munusamy Prabhakaran , Koh Geok Ling , Chan Claire Hian Tzer , Madhukumar Preetha , Thung Jee Liang , Tan Kiat Tee Benita , Ong Kong Wee , Yong Wei Sean , Sim Yirong , Oey Chung Lie , Lim Sue Zann , Chan Mun Yew Patrick , Ho Teng Swan Juliana , Khoo Boon Kheng James , Wong Su Lin Jill , Thng Choon Hua , Chong Bee Kiang , Tan Ern Yu , Tan Veronique Kiak-Mien , Lee Ann Siew Gek
Published: November 2019

Although mammography is the gold standard for breast cancer screening, the high rates of false-positive mammograms remain a concern. Thus, there is an unmet clinical need for a non-invasive and reliable test to differentiate between malignant and benign breast lesions in order to avoid subjecting patients with abnormal mammograms to unnecessary follow-up diagnostic procedures. Serum samples from 116 malignant breast lesions and 64 benign breast lesions were comprehensively profiled for 2,083 microRNAs (miRNAs) using next-generation sequencing. Of the 180 samples profiled, three outliers were removed based on the principal component analysis (PCA), and the remaining samples were divided into training (n = 125) and test (n = 52) sets at a 70:30 ratio for further analysis. In the training set, significantly differentially expressed miRNAs (adjusted p < 0.01) were identified after correcting for multiple testing using a false discovery rate. Subsequently, a predictive classification model using an eight-miRNA signature and a Bayesian logistic regression algorithm was developed. Based on the receiver operating characteristic (ROC) curve analysis in the test set, the model could achieve an area under the curve (AUC) of 0.9542. Together, this study demonstrates the potential use of circulating miRNAs as an adjunct test to stratify breast lesions in patients with abnormal screening mammograms.
Ca-based Catalysts for the Production of High-Quality Bio-Oils from the Catalytic Co-Pyrolysis of Grape Seeds and Waste Tyres
Authors: Sanahuja-Parejo Olga , Veses Alberto , López José Manuel , Murillo Ramón , Callén María Soledad , García Tomás
Published: November 2019

The catalytic co-pyrolysis of grape seeds and waste tyres for the production of high-quality bio-oils was studied in a pilot-scale Auger reactor using different low-cost Ca-based catalysts. All the products of the process (solid, liquid, and gas) were comprehensively analysed. The results demonstrate that this upgrading strategy is suitable for the production of better-quality bio-oils with major potential for use as drop-in fuels. Although very good results were obtained regardless of the nature of the Ca-based catalyst, the best results were achieved using a high-purity CaO obtained from the calcination of natural limestone at 900 °C. Specifically, by adding 20 wt% waste tyres and using a feedstock to CaO mass ratio of 2:1, a practically deoxygenated bio-oil (0.5 wt% of oxygen content) was obtained with a significant heating value of 41.7 MJ/kg, confirming its potential for use in energy applications. The total basicity of the catalyst and the presence of a pure CaO crystalline phase with marginal impurities seem to be key parameters facilitating the prevalence of aromatisation and hydrodeoxygenation routes over the de-acidification and deoxygenation of the vapours through ketonisation and esterification reactions, leading to a highly aromatic biofuel. In addition, owing to the CO2-capture effect inherent to these catalysts, a more environmentally friendly gas product was produced, comprising H2 and CH4 as the main components.
A Proposed DoS Detection Scheme for Mitigating DoS Attack Using Data Mining Techniques
Authors: Djanie Kotey Seth , Tutu Tchao Eric , Dzisi Gadze James
Published: November 2019

A denial of service (DoS) attack in a computer network is an attack on the availability of computer resources to prevent users from having access to those resources over the network. Denial of service attacks can be costly, capable of reaching $100,000 per hour. Development of easily-accessible, simple DoS tools has increased the frequency and reduced the level of expertise needed to launch an attack. Though these attack tools have been available for years, there has been no proposed defense mechanism targeted specifically at them. Most defense mechanisms in literature are designed to defend attacks captured in datasets like the KDD Cup 99 dataset from 20 years ago and from tools no longer in use in modern attacks. In this paper, we capture and analyze traffic generated by some of these DoS attack tools using Wireshark Network Analyzer and propose a signature-based DoS detection mechanism based on SVM classifier to defend against attacks launched by these attack tools. Our proposed detection mechanism was tested with Snort IDS and compared with some already existing defense mechanisms in literature and had a high detection accuracy, low positive rate and fast detection time.
Study in Optical and Mechanical Properties of Nd3+, Y3+: SrF2 Transparent Ceramics Prepared by Hot-Pressing and Hot-Forming Techniques
Authors: Qin Shaoyong , Song Jinghong , Wang Wuxiao , Mei Bingchu , Li Weiwei , Xia Yuanming
Published: November 2019

Nd3+, Y3+: SrF2 transparent ceramics were successfully synthesized by two methods: hot-forming and hot-pressing techniques. The mechanical properties and optical properties of the hot-formed Nd3+, Y3+: SrF2 transparent ceramics were much better than that of single crystal. On the other hand, the transmittance of the hot-formed transparent ceramics with different deformation rate reached up to 90% at 1054 nm, which is superior to the hot-pressed ceramics. Furthermore, the fracture toughness of hot-formed Nd3+, Y3+: SrF2 transparent ceramics with the deformation rate of 51% reached up to 0.70 MPa m1/2, which is nearly 1.5 times higher than that of as-grown single crystal. The full width at half maximum (FWHM) of the hot-formed ceramic is larger than that of the single crystal at 1053 nm under continuous-wave (CW) laser operation. The thermal conductivity of Nd3+, Y3+: SrF2 single crystal and hot-formed ceramics were also discussed.
A Simple Dip-Coating Method of SnO2-NiO Composite Thin Film on a Ceramic Tube Substrate for Methanol Sensing
Authors: Liu Tianyu , Xu Longxiao , Wang Xiangyue , Li Qiuyang , Cui Qiang , Suo Hui , Zhao Chun
Published: November 2019

In this work, SnO2-NiO composite thin film was successfully grown on a ceramic tube substrate directly by a simple dip-coating method combined with annealing. Characterization analysis demonstrates that uniform SnO2 film consists of a great number of nanospheres and NiO grows on SnO2 as an agglomerated block. In comparison to the pure SnO2 sample, the SnO2-NiO composite thin films gas sensor exhibits superior methanol sensing properties at 225 °C. The gas response to 10 ppm methanol reached 15.12 and the response and recovery times were 8 s and 7 s, respectively. The excellent selectivity and recovery rate are explained by the unique properties of the NiO semiconductor and the higher sensor response is attributed to the pivotal heterojunction effect.
Supportive Peer Feedback in Tertiary Education: Analysis of Pre-Service Teachers’ Perceptions
Authors: Cañabate Dolors , Nogué Lluís , Serra Teresa , Colomer Jordi
Published: November 2019

To acquire knowledge about student-mediated peer-to-peer collaborative activities, pre-service teachers’ perceptions of peer feedback are analyzed and categorized as receiver, provider, or cognitive feedback. A questionnaire of 15 survey questions concerning supportive feedback from peers was designed and validated using assessments from more than 200 pre-service teachers. The questionnaire was aligned with the activities promoting supportive feedback between pre-service teachers from three bachelor’s degrees at a tertiary education institution. Their perceptions were then quantified in terms of the peer feedback categories. While there were significant correlations between the scores for all 15 questions, real insights were produced when the highest correlations were analyzed. As such, being involved as both feedback providers and receivers was highly rated. The self-efficacy of pre-service teachers receiving feedback, (i.e., the extent to which peer instructional strategies and the selected learning tasks were cognitively challenging so as to improve receiver feedback), proved to be correlated with their perceptions of involvement, autonomy, and structure. Likewise, motivation for providing or receiving feedback was also closely correlated with the self-efficacy of pre-service teachers providing feedback. Finally, all three questions in the cognitive feedback category were highly correlated. The pre-service teachers were, thus, motivated to improve their learning and considered feedback as a useful task and as a way to strengthen their relationships with their peers.
Performance of Feature-Based Techniques for Automatic Digital Modulation Recognition and Classification—A Review
Authors: Al-Nuaimi Dhamyaa H. , Hashim Ivan A. , Zainal Abidin Intan S. , Salman Laith B. , Mat Isa Nor Ashidi
Published: November 2019

The demand for bandwidth-critical applications has stimulated the research community not only to develop new ways of communication, but also to use the existing spectrum efficiently. Networks have become dynamic and heterogeneous. Receivers have received various signals that can be modulated differently. Automatic modulation classification (AMC) is a key procedure for present and next-generation communication networks, and facilitates the demodulation process at the receiver side. Under the presence of noise from the channel, the transmitter and receiver with its unknown parameters, such as carrier frequency, phase offset, signal power, and timing information, have become cumbersome because detecting the modulation scheme of the received signal is a complicated procedure. Two main methods, namely maximum likelihood functions and the signal statistical feature-based (FB) approach, are used for the automatic classification of modulated signals. In this study, a comprehensive survey of various modulation techniques based on FB approach is conducted. In this research, a number of basic features that are usually used in determining and discriminating modulation types were investigated. The classifier that was used in the discrimination process is studied in detail and compared to other types of classifiers to help the reader determine the limitations associated with the FB approach. Both classifiers and basic features were compared, and their advantages and disadvantages were investigated based on previous researches to determine the best type of classifier and the set of features in relation to each discrimination environment. This work serves as a guide for researchers of AMC to determine the suitable features and algorithms.
Correction of Optical Delay Line Errors in Terahertz Time-Domain Spectroscopy
Authors: Mamrashev Alexander , Minakov Fedor , Maximov Lev , Nikolaev Nazar , Chapovsky Pavel
Published: November 2019

One of the key elements of terahertz time-domain spectrometers is the optical delay line. Usually it consists of a motorized translation stage and a corner reflector mounted on its top. Errors in the positioning of the translation stage lead to various distortions of the measured waveform of terahertz pulses and, therefore, terahertz spectra. In this paper, the accuracy of position measurements is improved by using an optical encoder. Three types of systematic errors are found: Increasing and periodic offsets of the translation stage position, as well as a drift of its initial position in a series of consecutive measurements. The influence of the detected errors on the measured terahertz spectra is studied and correction methods are proposed.
Spatial Information Platform with VWorld for Improving User Experience in Limited Web Environment
Authors: Lee Ahyun , Jang Insung
Published: November 2019

VWorld Data Center (VDC), operated by the Ministry of Land, Infrastructure, and Transport of South of Korea, provides the latest high-quality spatial information of South Korea. VWorld data include aerial images, digital elevation models, 3D buildings, 3D bridges, roads, administrative information, etc. We present a 3D spatial information platform that uses VWorld data. This platform is based on the web browser environment and supports cross platform by complying with WebGL and web standards. The 3D-terrain tile structure has a quadtree-based detail level for high-resolution rendering. When rendering different tile levels or sizes simultaneously, abnormal gaps occur between the tiles. We propose the use of a specially shaped 3D terrain object model to minimize these gaps. This model can be used and verified using the service site of the WebGL-based VWorld spatial information platform. Our platform has a limited environment and runs in a web browser while requesting real-time spatial information data from VDC. VWorld data cannot be stored locally by policy. We improve the frame rate in such way that it can easily be used in a limited web browser environment or even a computing environment without a graphics processing unit. We intend to officially present the proposed method to the VDC and apply it. We expect our platform to be used for various web-based geospatial applications.
Lifetime Estimation and Failure Risk Analysis in a Power Stage Used in Wind-Fuel Cell Hybrid Energy Systems
Authors: Rastayesh Sima , Bahrebar Sajjad , Bahman Amir Sajjad , Sørensen John Dalsgaard , Blaabjerg Frede
Published: November 2019

This paper presents a methodology based on the failure mode and effect analysis (FMEA) to analyze the failures in the power stage of wind-fuel cell hybrid energy systems. Besides, fault tree analysis (FTA) is applied to describe the probabilistic failures in the vital subcomponents. Finally, the reliability assessment of the system is carried out for a five-year operation that is guaranteed by the manufacturer. So, as the result, the reliability analysis proves that the metal oxide semiconductor field effect transistor (MOSFET) and electrolytic capacitor are the most critical components that introduce damages in the power circuit. Moreover, a comparative study on the reliability assessment by the exponential distribution and the Weibull distribution show that the B1 lifetime obtained by the Weibull distribution is closer to reality.
Olfactory Cues of Restaurant Wait Staff Modulate Patrons’ Dining Experiences and Behavior
Authors: Singh Asmita , Beekman Thadeus L. , Seo Han-Seok
Published: November 2019

Ambient scents at retail stores have been found to modulate customer perceptions and attitudes toward retail products and stores. Although ambient scent effects have also been observed in restaurant settings, little is known about the scent-related influences of restaurant wait staff on patron perception and behavior. This study aimed to determine whether olfactory cues from restaurant wait staff can affect patrons’ dining experiences and interpersonal behavior with respect to menu choice, flavor perception, overall liking of meal items, meal satisfaction, consumption amount, and tip amount for wait staff. A total of 213 adults with no olfactory impairments were asked to select and consume one of four chicken meat menu items: baked, broiled, fried, and smoked chicken, in a mock restaurant setting, under one of the three most likely scents of wait staff: congruent (smoky barbecue scent), fragrance (perfume scent), and no scent (control) applied to fabric aprons of wait staff. The results showed that menu choice and flavor perception of chicken meat items did not differ in the presence of the three scent conditions. The effects of wait staff scents on overall liking of chicken meat items, meal satisfaction, and tip amount for wait staff were found to differ as a function of patron gender. Female patrons gave higher ratings of overall liking and meal satisfaction under the fragrance scent condition than under the no scent condition, while male patrons showed no effect with respect to overall liking and an opposite result in the meal satisfaction. Female patrons gave larger tips to wait staff under the congruent scent condition than under the no scent condition, while male patrons exhibited no effect. Patrons also were found to consume chicken meat items the least under the congruent scent condition. In conclusion, this study provides new empirical evidence that wait staff scents at restaurants can affect patrons’ dining experiences and interpersonal behavior and that the effects of such scents vary as a function of patron gender.
Research Progress on Plant RING-Finger Proteins
Authors: Sun Jinhao , Sun Yuhe , Ahmed Rana Imtiaz , Ren Angyan , Xie Minmin
Published: November 2019

E3 ubiquitin ligases are the most expanded components of the ubiquitin proteasome system (UPS). They mediate the recognition of substrates and later transfer the ubiquitin (Ub) of the system. Really Interesting New Gene (RING) finger proteins characterized by the RING domain, which contains 40–60 residues, are thought to be E3 ubiquitin ligase. RING-finger proteins play significant roles in plant growth, stress resistance, and signal transduction. In this study, we mainly describe the structural characteristics, classifications, and subcellular localizations of RING-finger proteins, as well the physiological processes of RING-finger proteins in plant growth and development. We also summarize the functions of plant RING-finger proteins in plant stress resistance. Finally, further research on plant RING-finger proteins is suggested, thereby establishing a strong foundation for the future study of plant RING-finger proteins.
Osteoarthritis in the Middle-Aged and Elderly in China: Prevalence and Influencing Factors
Authors: Sun Xueshan , Zhen Xuemei , Hu Xiaoqian , Li Yuanyuan , Gu Shuyan , Gu Yuxuan , Dong Hengjin
Published: November 2019

Background: Osteoarthritis is a common joint disease, with the acceleration of the aging process in China, it has troubled the middle-aged and elderly. There have been some epidemiological studies of osteoarthritis conducted in one single site, and most of them were on knee osteoarthritis. The results varied greatly between different surveys. There was still a lack of large-scale and multicenter epidemiological studies of osteoarthritis. This paper aimed to estimate the overall prevalence of lumbar osteoarthritis, cervical osteoarthritis, hand osteoarthritis, knee osteoarthritis, and hip osteoarthritis in the middle-aged and elderly in China by summarizing the existing publications. Methods: We comprehensively searched publications on 1 January 2019 in PubMed, Web of Science, Embase, Cochrane Library, CBM, CNNI, VIP, and Wan Fang. Epidemiological publications on osteoarthritis in the middle-aged and elderly Chinese published from 2000 to 2018 were summarized and analyzed by means of systematic review and meta-analysis. Data of prevalence of osteoarthritis in five joints were extracted from the included publications. The Hoy 2012 tool was used to assess the risk of bias of included studies. Results: After performing a systematic search in eight databases and manually searching, 3058 articles were obtained, and 21 articles were included in the meta-analysis. Lumbar osteoarthritis was the most prevalent with a prevalence of 25.03% (95% CI: 0.1444–0.3562). The prevalence of knee osteoarthritis followed, which was 21.51% (95% CI: 0.1873–0.2429). The prevalence of cervical osteoarthritis was 20.46% (95% CI: 0.1244–0.2849). The prevalence of hand osteoarthritis was 8.99% (95% CI: 0.0435–0.1364). The prevalence of hip osteoarthritis was not pooled due to its lack of data. Higher prevalence of knee, hand, lumbar, and cervical osteoarthritis was seen in the female group and southern regions. The prevalence of knee and hand osteoarthritis increased with age. The prevalence of lumbar and cervical osteoarthritis increased with age. There was also a trend that the prevalence increased with age before 70 years old and slightly decreased in the oldest ages. Conclusions: The lumbar joint was the joint most prevalently affected by osteoarthritis, followed by the prevalence of knee, cervical, hand, and hip joint osteoarthritis. Women, the southern population, and the older population are more susceptible to osteoarthritis. The paucity of epidemiology data of osteoarthritis in China appeals for more population-based surveys being conducted in the future. Based on the relatively high prevalence of osteoarthritis obtained from this review, self-management and community-based management should be considered, which can provide experience from the management of hypertensions and diabetes.
Barriers and Facilitators to the Adoption and Sustained Use of Cleaner Fuels in Southwest Cameroon: Situating ‘Lay’ Knowledge within Evidence-Based Policy and Practice
Authors: Stanistreet Debbi , Hyseni Lirije , Puzzolo Elisa , Higgerson James , Ronzi Sara , Anderson de Cuevas Rachel , Adekoje Oluwakorede , Bruce Nigel , Mbatchou Ngahane Bertrand , Pope Daniel
Published: November 2019

Approximately four million people die each year in low- and middle-income countries from household air pollution (HAP) due to inefficient cooking with solid fuels. Liquid Petroleum Gas (LPG) offers a clean energy option in the transition towards renewable energy. This qualitative study explored lay knowledge of barriers and facilitators to scaling up clean fuels in Cameroon, informed by Quinn et al.’s Logic Model. The model has five domains and we focused on the user and community needs domain, reporting the findings of 28 semi-structured interviews (SSIs) and four focus group discussions (FGDs) that explored the reasons behind fuel use choices. The findings suggest that affordability, safety, convenience, and awareness of health issues are all important influences on decision making to the adoption and sustained use of LPG, with affordability being the most critical issue. We also found the ability of clean fuels to meet cooking needs to be central to decision-making, rather than an aspect of convenience, as the logic model suggests. Local communities provide important insights into the barriers and facilitators to using clean fuels. We adapt Quinn et al.’s logic model accordingly, giving more weight to lay knowledge so that it is better positioned to inform policy development.
Technology Acceptance and Quality of Life among Older People Using a TUI Application
Authors: Bong Way Kiat , Bergland Astrid , Chen Weiqin
Published: November 2019

Good quality of life is important for healthy ageing. Studies have shown that although information and communication technology can improve older people’s quality of life, their technology acceptance level is rather low. Tangible user interfaces (TUIs) enable people to interact with the digital world through everyday physical objects, thus offering more intuitive digital environments for older people. In this study, we employ a TUI prototype to investigate the relationship between older people’s technology acceptance and quality of life, the changes in these outcome measures after using TUI, and the associations between them. The TUI prototype, Tangible Cup was used by 20 older participants over a period of three months. Data were collected using the technology acceptance model (TAM) questionnaire, the older people’s quality of life (OPQOL) questionnaire and semi-structured interviews. The results showed some positive changes in technology acceptance after the use of Tangible Cup. However, no change in the quality of life was found. While statistically significant correlations between the change in technology acceptance and the change in quality of life were observed, limitations such as small sample size and participants not accurately representing the target population should be noted. Thus, further research is needed to better understand the associations between the change in technology acceptance and the change in quality of life.
Disaster Chain Analysis of Avalanche and Landslide and the River Blocking Dam of the Yarlung Zangbo River in Milin County of Tibet on 17 and 29 October 2018
Authors: Jia Huicong , Chen Fang , Pan Donghua
Published: November 2019

As a “starting zone” and “amplifier” of global climate change, the Qinghai–Tibet Plateau is very responsive to climate change. The global temperature rise has led directly to an acceleration of glacial melting in the plateau and various glacier avalanche disasters have frequently occurred. The landslide caused by glacier avalanches will damage the surrounding environment, causing secondary disasters and a disaster chain effect. Take the disaster chain of the Yarlung Zangbo River at Milin County in Tibet on 17 and 29 October 2018 as an example; a formation mechanical model was proposed. The evolution mechanism for the chain of events is as follows: glacial melt → loose moraine deposit → migration along the steep erosion groove resulting in glacier clastic deposition then debris flow → formation of the dam plug to block the river → the dammed lake. This sequence of events is of great significance for understanding the developmental trends for future avalanches, landslides, and river blocking dam disasters, and for disaster prevention planning and mitigation in the Qinghai–Tibet Plateau.
Vegetation Change and Its Relationship with Climate Factors and Elevation on the Tibetan Plateau
Authors: Zhang Yixin , Xu Guoce , Li Peng , Li Zhanbin , Wang Yun , Wang Bin , Jia Lu , Cheng Yuting , Zhang Jiaxin , Zhuang Shaohao , Chen Yiting
Published: November 2019

As the “roof of the world”, the Tibetan Plateau (TP) is a unique geographical unit on Earth. In recent years, vegetation has gradually become a key factor reflecting the ecosystem since it is sensitive to ecological changes especially in arid and semi-arid areas. Based on the normalized difference vegetation index (NDVI) dataset of TP from 2000 to 2015, this study analyzed the characteristics of vegetation variation and the correlation between vegetation change and climatic factors at different time scales, based on a Mann–Kendall trend analyses, the Hurst exponent, and the Pettitt change-point test. The results showed that the vegetation fractional coverage (VFC) generally increased in the past 16 years, with 60.3% of the TP experiencing an increase, of which significant (p < 0.05) increases accounted for 28.79% and were mainly distributed in the north of the TP. Temperature had the largest response with the VFC on the seasonal scale. During the growing season, the correlation between precipitation and sunshine duration with VFC was high (p < 0.05). The change-points of the VFC were mainly distributed in the north of the TP during 2007–2009. Slope and elevation had an impact on the VFC; the areas with large vegetation change are mainly distributed in slopes <20° and elevation of 3000–5000 m. For elevation above 3000–4000 m, the response of the VFC to precipitation and temperature was the strongest. This study provided important information for ecological environment protection and ecosystem degradation on the Tibetan Plateau.
A Method of Watershed Delineation for Flat Terrain Using Sentinel-2A Imagery and DEM: A Case Study of the Taihu Basin
Authors: Li Leilei , Yang Jintao , Wu Jin
Published: November 2019

Accurate watershed delineation is a precondition for runoff and water quality simulation. Traditional digital elevation model (DEM) may not generate realistic drainage networks due to large depressions and subtle elevation differences in local-scale plains. In this study, we propose a new method for solving the problem of watershed delineation, using the Taihu Basin as a case study. Rivers, lakes, and reservoirs were obtained from Sentinel-2A images with the Canny algorithm on Google Earth Engine (GEE), rather than from DEM, to compose the drainage network. Catchments were delineated by modifying the flow direction of rivers, lakes, reservoirs, and overland flow, instead of using DEM values. A watershed was divided into the following three types: Lake, reservoir, and overland catchment. A total of 2291 river segments, seven lakes, eight reservoirs, and 2306 subwatersheds were retained in this study. Compared with results from HydroSHEDS and Arc Hydro, the proposed method retains crisscross structures in the topology and prevented erroneous streamlines in large lakes. High-resolution Sentinel-2A images available on the GEE have relatively greater merits than DEMs for precisely representing drainage networks and catchments, especially in the plains area. Because of the higher accuracy, this method can be used as a new solution for watershed division in the plains area.
Methanol Synthesis from CO2: A Review of the Latest Developments in Heterogeneous Catalysis
Authors: Guil-López R. , Mota N. , Llorente J. , Millán E. , Pawelec B. , Fierro J.L.G. , Navarro R. M.
Published: November 2019

Technological approaches which enable the effective utilization of CO2 for manufacturing value-added chemicals and fuels can help to solve environmental problems derived from large CO2 emissions associated with the use of fossil fuels. One of the most interesting products that can be synthesized from CO2 is methanol, since it is an industrial commodity used in several chemical products and also an efficient transportation fuel. In this review, we highlight the recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to methanol. The main efforts focused on the improvement of conventional Cu/ZnO based catalysts and the development of new catalytic systems targeting the specific needs for CO2 to methanol reactions (unfavourable thermodynamics, production of high amount of water and high methanol selectivity under high or full CO2 conversion). Major studies on the development of active and selective catalysts based on thermodynamics, mechanisms, nano-synthesis and catalyst design (active phase, promoters, supports, etc.) are highlighted in this review. Finally, a summary concerning future perspectives on the research and development of efficient heterogeneous catalysts for methanol synthesis from CO2 will be presented.
A Bibliometric Survey of Paraffin/Olefin Separation Using Membranes
Authors: Miranda Débora Micheline Vaz de , Dutra Luciana da Silva , Way Débora , Amaral Nicolis , Wegenast Frederico , Scaldaferri Maria Clara , Jesus Normando , Pinto José Carlos
Published: November 2019

Bibliometric studies allow to collect, organize and process information that can be used to guide the development of research and innovation and to provide basis for decision-making. Paraffin/olefin separations constitute an important industrial issue because cryogenic separation methods are frequently needed in industrial sites and are very expensive. As a consequence, the use of membrane separation processes has been extensively encouraged and has become an attractive alternative for commercial separation processes, as this may lead to reduction of production costs, equipment size, energy consumption and waste generation. For these reasons, a bibliometric survey of paraffin/olefin membrane separation processes is carried out in the present study in order to evaluate the maturity of the technology for this specific application. Although different studies have proposed the use of distinct alternatives for olefin/paraffin separations, the present work makes clear that consensus has yet to be reached among researchers and technicians regarding the specific membranes and operation conditions that will make these processes scalable for large-scale commercial applications.
Characterization of Hot Deformation Behavior and Processing Maps of Mg-3Sn-2Al-1Zn-5Li Magnesium Alloy
Authors: Guo Yuhang , Xuanyuan Yaodong , Lia Chunnan , Yang Sen
Published: November 2019

The dynamic microstructure evolution of Mg-3Sn-2Al-1Zn-5Li magnesium alloy during hot deformation is studied by hot compression tests over the temperature range of 200–350 °C under the strain rate of 0.001–1 s−1, whereafter constitutive equations and processing maps are developed and constructed. In most of cases, the material shows typical dynamic recrystallization (DRX) features, with a signal peak value followed by a gradual decrease. The value of Q (deformation activation energy) is 138.89414 kJ/mol, and the instability domains occur at high strain rate but the stability domains are opposite, and the optimum hot working parameter for the studied alloy is determined to be 350 °C/0.001 s−1 according to the processing maps. Within 200–350 °C, the operating mechanism of dynamic recrystallization (DRX) of Mg-3Sn-2Al-1Zn-5Li alloy during hot deformation is mainly affected by strain rate. Dynamic recrystallization (DRX) structures are observed from the samples at 300 °C/0.001 s−1 and 350 °C/0.001 s−1, which consist of continuous DRX (CDRX) and discontinuous DRX (DDRX). However, dynamic recovery (DRV) still dominates the softening mechanism. At the grain boundaries, mass dislocation pile-ups and dislocation tangle provide sites for potential nucleation. Meanwhile, flow localization bands are observed from the samples at 200 °C/1 s−1 and 250 °C/0.1 s−1 as the main instability mechanism.
Investigating the Effect of Artificial Flavours and External Information on Consumer Liking of Apples
Authors: Endrizzi Isabella , Aprea Eugenio , Betta Emanuela , Charles Mathilde , Zambanini Jessica , Gasperi Flavia
Published: November 2019

In this paper, the influence of flavour modification, artificially induced, on consumer acceptability of apple fruit is studied. The method consists of modifying the flavour of a real food matrix dipping apples into flavour solutions. Two flavouring compounds (linalool and anethole) that were responsible of “floral” and “anise” aroma descriptors, respectively, were considered here. The effectiveness of flavouring treatments was confirmed by instrumental analysis of volatile compounds profile using solid-phase microextraction gas chromatography/mass spectrometry (SPME/GC-MS) and by discriminative and descriptive sensory analyses. The effect of flavour-impact was evaluated in an informed test on the two flavoured ‘Fuji’ apples: the consumers were asked to evaluate the global liking of the treated and non-treated apples with information regarding the aromatic features. Participants’ additional data on the characteristics on their “ideal apple”, attitudes toward natural food, food neophobia, and demographic data were also recorded by specific questionnaires. A statistically significant effect on liking was found for the flavour factor, whereas external information only affected apple acceptance for subgroups of consumers, depending on their attitude towards food.
Nasal Drug Delivery of Anticancer Drugs for the Treatment of Glioblastoma: Preclinical and Clinical Trials
Authors: Bruinsmann Franciele Aline , Richter Vaz Gustavo , de Cristo Soares Alves Aline , Aguirre Tanira , Raffin Pohlmann Adriana , Stanisçuaski Guterres Silvia , Sonvico Fabio
Published: November 2019

Glioblastoma (GBM) is the most lethal form of brain tumor, being characterized by the rapid growth and invasion of the surrounding tissue. The current standard treatment for glioblastoma is surgery, followed by radiotherapy and concurrent chemotherapy, typically with temozolomide. Although extensive research has been carried out over the past years to develop a more effective therapeutic strategy for the treatment of GBM, efforts have not provided major improvements in terms of the overall survival of patients. Consequently, new therapeutic approaches are urgently needed. Overcoming the blood–brain barrier (BBB) is a major challenge in the development of therapies for central nervous system (CNS) disorders. In this context, the intranasal route of drug administration has been proposed as a non-invasive alternative route for directly targeting the CNS. This route of drug administration bypasses the BBB and reduces the systemic side effects. Recently, several formulations have been developed for further enhancing nose-to-brain transport, mainly with the use of nano-sized and nanostructured drug delivery systems. The focus of this review is to provide an overview of the strategies that have been developed for delivering anticancer compounds for the treatment of GBM while using nasal administration. In particular, the specific properties of nanomedicines proposed for nose-to-brain delivery will be critically evaluated. The preclinical and clinical data considered supporting the idea that nasal delivery of anticancer drugs may represent a breakthrough advancement in the fight against GBM.
Parabens Adsorption onto Activated Carbon: Relation with Chemical and Structural Properties
Authors: Moreno-Marenco Astrid Roxanna , Giraldo Liliana , Moreno-Piraján Juan Carlos
Published: November 2019

Parabens (alkyl-p-hidroxybenzoates) are antimicrobial preservatives used in personal care products, classified as an endocrine disruptor, so they are considered emerging contaminants. A raw version of activated carbons obtained from African palm shell (Elaeis guineensis) modified chemically by impregnation with salts of CaCl2 (GC2), MgCl2 (GM2) and Cu(NO3)2 (GCu2) at 2% wt/v and carbonized in CO2 atmosphere at 1173 K was prepared. The process of adsorption of methyl (MePB) and ethylparaben (EtPB) from aqueous solution on the activated carbons at 18 °C was studied and related to the interactions between the adsorbate and the adsorbent, which can be quantified through the determination of immersion enthalpies in aqueous solutions of corresponding paraben, showing the lowest-value carbon GM2, which has a surface area of 608 m2 × g−1, while the highest values correspond to the activated carbon GCu2, with a surface area of 896 m2 × g−1 and the highest content of surface acid sites (0.42 mmol × g−1), such as lactonic and phenolic compounds, which indicates that the adsorbate–adsorbent interactions are favored by the presence of these, with interaction enthalpies that vary between 5.72 and 51.95 J × g−1 for MePB adsorption and 1.24 and 52.38 J × g−1 for EtPB adsorption showing that the process is endothermic.
Considerations on the Rational Design of Covalently Conjugated Cell-Penetrating Peptides (CPPs) for Intracellular Delivery of Proteins: A Guide to CPP Selection Using Glucarpidase as the Model Cargo Molecule
Authors: Behzadipour Yasaman , Hemmati Shiva
Published: November 2019

Access of proteins to their intracellular targets is limited by a hydrophobic barrier called the cellular membrane. Conjugation with cell-penetrating peptides (CPPs) has been shown to improve protein transduction into the cells. This conjugation can be either covalent or non-covalent, each with its unique pros and cons. The CPP-protein covalent conjugation may result in undesirable structural and functional alterations in the target protein. Therefore, we propose a systematic approach to evaluate different CPPs for covalent conjugations. This guide is presented using the carboxypeptidase G2 (CPG2) enzyme as the target protein. Seventy CPPs —out of 1155— with the highest probability of uptake efficiency were selected. These peptides were then conjugated to the N- or C-terminus of CPG2. Translational efficacy of the conjugates, robustness and thermodynamic properties of the chimera, aggregation possibility, folding rate, backbone flexibility, and aspects of in vivo administration such as protease susceptibility were predicted. The effect of the position of conjugation was evaluated using unpaired t-test (p < 0.05). It was concluded that N-terminal conjugation resulted in higher quality constructs. Seventeen CPP-CPG2/CPG2-CPP constructs were identified as the most promising. Based on this study, the bioinformatics workflow that is presented may be universally applied to any CPP-protein conjugate design.
Analysis of the Heterogeneous Distribution of Amiloride and Propranolol in Dried Blood Spot by UHPLC-FLD and MALDI-IMS
Authors: Uribe Beatriz , González Oskar , Blanco María Encarnación , Albóniga Oihane Elena , Alonso María Luz , Alonso Rosa María
Published: November 2019

Dried blood spot (DBS) has lately experienced an increase in its use in bioanalysis due to its several advantages compared with traditional blood sampling methods. Nevertheless, the use of DBS with quantitative purposes is hindered by the heterogeneous distribution of some compounds in the supporting matrix and the dependence of the response on different factors, such as the hematocrit, blood volume, and sampling position. In this study the effect of those factors in the analytical response was investigated by ultra high performance liquid chromatography coupled to fluorescence detection, using amiloride and propranolol as model compounds. The results showed a heterogeneous and drug-dependent distribution of the compounds in the blood spot. While amiloride concentration was higher in the center, propranolol concentration was higher in the periphery of the spot. Besides, the influence of the hematocrit on the quantitative results was observed. MALDI mass spectrometry imaging (MALDI-IMS) has allowed study of the distribution of the two cardiovascular drugs when they were placed in the DBS card using water:methanol solutions, demonstrating that they followed a similar distribution pattern as in blood. This work has showed the potentiality of the MALDI-IMS technique to predict the distribution of the drugs in the DBS card.
Biosynthesis of Isoprene Units in Euphorbia lathyris Laticifers vs. Other Tissues: MVA and MEP Pathways, Compartmentation and Putative Endophytic Fungi Contribution
Authors: Gastaldo Clément , Lipko Agata , Motsch Estelle , Adam Pierre , Schaeffer Philippe , Rohmer Michel
Published: November 2019

Euphorbia species are characterized by a net of laticifers producing large amounts of triterpenes. These hydrocarbon-like metabolites can be converted into fuel by the methods of the oil industry. Euphorbia lathyris is easily grown at an industrial scale. In an attempt to increase its triterpene production, the metabolic pathways leading to isoprenoid were investigated by incorporation of 13C labeled glucose and mevalonate and 2H labeled deoxyxylulose as well as by natural abundance isotope ratio GC-MS. Latex triterpenes are exclusively synthesized via the mevalonate (MVA) pathway: this may orient future search for improving the triterpene production in E. lathyris. Phytosterols and their precursors are mainly derived from MVA pathway with a slight contribution of the methylerythritol phosphate (MEP) pathway, whereas phytol is issued from MEP pathway with a minor contribution of the MVA pathway: this is in accordance with the metabolic cross-talk between cytosolic and plastidial compartments in plants. In addition, hopenol B behaved differently from the other latex triterpenes. Its 13C isotope abundance after incorporation of 13C labeled glucose and its natural abundance δ2H signature clearly differed from those of the other latex triterpenes indicating another metabolic origin and suggesting that it may be synthesized by an endophytic fungus.
The Mode of Cytokinin Functions Assisting Plant Adaptations to Osmotic Stresses
Authors: Gujjar Ranjit Singh , Supaibulwatana Kanyaratt
Published: November 2019

Plants respond to abiotic stresses by activating a specific genetic program that supports survival by developing robust adaptive mechanisms. This leads to accelerated senescence and reduced growth, resulting in negative agro-economic impacts on crop productivity. Cytokinins (CKs) customarily regulate various biological processes in plants, including growth and development. In recent years, cytokinins have been implicated in adaptations to osmotic stresses with improved plant growth and yield. Endogenous CK content under osmotic stresses can be enhanced either by transforming plants with a bacterial isopentenyl transferase (IPT) gene under the control of a stress inducible promoter or by exogenous application of synthetic CKs. CKs counteract osmotic stress-induced premature senescence by redistributing soluble sugars and inhibiting the expression of senescence-associated genes. Elevated CK contents under osmotic stress antagonize abscisic acid (ABA) signaling and ABA mediated responses, delay leaf senescence, reduce reactive oxygen species (ROS) damage and lipid peroxidation, improve plant growth, and ameliorate osmotic stress adaptability in plants.
NTRC and Thioredoxin f Overexpression Differentially Induces Starch Accumulation in Tobacco Leaves
Authors: Ancín María , Larraya Luis , Fernández-San Millán Alicia , Veramendi Jon , Burch-Smith Tessa , Farran Inmaculada
Published: November 2019

Thioredoxin (Trx) f and NADPH-dependent Trx reductase C (NTRC) have both been proposed as major redox regulators of starch metabolism in chloroplasts. However, little is known regarding the specific role of each protein in this complex mechanism. To shed light on this point, tobacco plants that were genetically engineered to overexpress the NTRC protein from the chloroplast genome were obtained and compared to previously generated Trx f-overexpressing transplastomic plants. Likewise, we investigated the impact of NTRC and Trx f deficiency on starch metabolism by generating Nicotiana benthamiana plants that were silenced for each gene. Our results demonstrated that NTRC overexpression induced enhanced starch accumulation in tobacco leaves, as occurred with Trx f. However, only Trx f silencing leads to a significant decrease in the leaf starch content. Quantitative analysis of enzyme activities related to starch synthesis and degradation were determined in all of the genotypes. Zymographic analyses were additionally performed to compare the amylolytic enzyme profiles of both transplastomic tobacco plants. Our findings indicated that NTRC overexpression promotes the accumulation of transitory leaf starch as a consequence of a diminished starch turnover during the dark period, which seems to be related to a significant reductive activation of ADP-glucose pyrophosphorylase and/or a deactivation of a putative debranching enzyme. On the other hand, increased starch content in Trx f-overexpressing plants was connected to an increase in the capacity of soluble starch synthases during the light period. Taken together, these results suggest that NTRC and the ferredoxin/Trx system play distinct roles in starch turnover.