bluuebunny/crossref_metadata_2025 huggingface dataset:
Correction: Synthesis, characterization and electrochemical analysis of cysteine modified polymers for corrosion inhibition of mild steel in aqueous 1 M HCl
Authors: Jafar Mazumder Mohammad A.
Published: February 2019

Correction for ‘Synthesis, characterization and electrochemical analysis of cysteine modified polymers for corrosion inhibition of mild steel in aqueous 1 M HCl’ by Mohammad A. Jafar Mazumder et al., RSC Adv., 2019, 9, 4277–4294.
Regulating exciton bonding energy and bulk heterojunction morphology in organic solar cells via methyl-functionalized non-fullerene acceptors
Authors: Gao Wei , Liu Tao , Luo Zhenghui , Zhang Lin , Ming Ruijie , Zhong Cheng , Ma Wei , Yan He , Yang Chuluo
Published: February 2019

One methyl substituted CPTCN enables BTTIC-2M achieved OSCs efficiency of over 13%, significantly higher than those of no methyl and two methyl substituted CPTCN-based acceptors.
Modulating charge transfer dynamics for g-C3N4 through a dimension and interface engineered transition metal phosphide co-catalyst for efficient visible-light photocatalytic hydrogen generation
Authors: Zhang Fu , Zhang Jihua , Li Jianming , Jin Xu , Li Yapeng , Wu Min , Kang Xiongwu , Hu Tao , Wang Xiaoqi , Ren Wei , Zhang Genqiang
Published: February 2019

Ultrafine TMP nanodots decorated g-C3N4 hybrids with enhanced photocatalytic H2 production performance have been successfully prepared via the conformal coating of metal–glycolate and phosphorization method.
Centric-to-acentric structure transformation induced by a stereochemically active lone pair: a new insight for design of IR nonlinear optical materials
Authors: Lin Hua , Li Yan-Yan , Li Meng-Yue , Ma Zuju , Wu Li-Ming , Wu Xin-Tao , Zhu Qi-Long
Published: February 2019

New insight for design of NLO materials: a quaternary acentric semiconductor, La2CuSbS5, obtained by a stereochemically active lone pair induction (SALPI) strategy, with inspiration from the known centric La2CuInS5.
Use of Recast Intervention to Teach Causal Adverbials to Young Children With Developmental Language Disorder Within a Science Curriculum: A Single Case Design Study
Authors: Curran Maura , Owen Van Horne Amanda
Published: February 2019

Purpose

Language serves as an essential resource to learn about cause and effect throughout childhood. Causal adverbial sentences use causal conjunctions (e.g.,
because
,
so
) to join 2 clauses to express cause–effect relationships (
Diessel & Hetterle, 2011
). Causal adverbial sentences are frequently used to explain causal relationships in academic contexts, such as elementary school science and social studies classes (
Kinzie et al., 2014
;
J. Williams et al., 2014
). Children with developmental language disorder (DLD) are at risk for failure in these academically relevant language skills. Here, we investigated the effect of language intervention focused on causal adverbials on both causal adverbials and acquisition of science content in young children with DLD.

Method

A multiple-probe design was used to examine the effect of language intervention using recasts on production of causal adverbials and acquisition of science content for 7 preschool/kindergarten children with DLD. Child production of causal adverbials and an untreated control structure were analyzed.

Results

Six of 7 participants exhibited gains in production of causal adverbials containing
because
, with effect sizes ranging from small to large. Performances on daily probes of science content learning and science unit tests indicate that participants are able to learn science content, but the magnitude of gains may not relate to skill in causal adverbial production.

Conclusion

Language intervention for young children with DLD can effectively treat complex syntactic targets such as causal adverbials in the context of science instruction, but it is unclear whether this can affect science content learning.
Laryngeal Neuromuscular Response to Short- and Long-Term Vocalization Training in Young Male Rats
Authors: Lenell Charles , Newkirk Bethany , Johnson Aaron M.
Published: February 2019

Purpose

Although vocal training is often purported to restore and rebalance laryngeal muscle function, little is known about the direct effects of vocal training on the laryngeal muscles themselves. Consequently, parameters of vocal exercise dose, such as training duration and intensity, have not been well defined. The goal of this study was to use a behavioral animal model to determine the effects of short- and long-term ultrasonic vocalization (USV) training on USV acoustics, thyroarytenoid (TA) muscle neuromuscular junctions (NMJs), and TA muscle fiber size in adult rats.

Method

Twenty-four young adult male Long-Evans rats were divided into 3 groups (untrained control, 4-week training, and 8-week training). Baseline and posttraining USVs were recorded and acoustically analyzed for fundamental frequency, frequency bandwidth, amplitude, and duration. Presynaptic and postsynaptic NMJ morphological features and muscle fiber size were measured in the TA.

Results

USV training had no effect on USV acoustics. Eight weeks of USV training, however, resulted in a lower NMJ motor endplate dispersion ratio, consistent with previous findings. USV training did not affect fiber size within the TA muscle.

Conclusions

This study demonstrated that 8 weeks of USV training can induce peripheral neural adaptations in the NMJ of the TA muscle in young rats. The observed adaptations suggest that vocal training is consistent with endurance-type exercise, but the adaptations occur on a longer time scale than similar adaptations in the limb muscles.
System‐by‐design method for efficient linear array miniaturisation through low‐complexity isotropic lenses
Authors: Salucci M. , Tenuti L. , Gottardi G. , Hannan A. , Massa A.
Published: February 2019

The design of miniaturised linear arrays by using isotropic lenses with reduced complexity is addressed. The problem at hand is formulated as a global optimisation one, then solved by means of a computationally‐efficient customisation of the system‐by‐design (SbD) paradigm suitably integrated with the quasi‐conformal transformation optics method. To yield arbitrary transformation geometries with a limited set of degrees‐of‐freedom and to reduce the lens complexity, while guaranteeing the same radiation performance of a larger reference aperture, a spline‐based description of the lens shape is adopted. Representative numerical results are reported to assess the effectiveness as well as the computational efficiency of the proposed SbD‐based approach.
Effect of supply scaling on noise performance of 0.6–1.2 V continuous‐time delta‐sigma modulator
Authors: Hsu C.‐W. , Kinget P.R.
Published: February 2019

The dependence of the noise performance of a 0.6–1.2 V continuous‐time delta‐sigma modulator (DSM) on its supply voltage is analysed. The noise performance and benchmark figure of merit (FoM) mainly depend on the power dissipation, thermal noise contributions from the analogue loop filter, and the quantisation noise from the quantisers. Theoretical estimates for the supply dependence of loop noise and quantisation noise, and their respective FoM are derived and verified with simulations for a 2 MHz third‐order continuous‐time DSM, while operating from a supply between 0.6 and 1.2 V. At a larger supply voltage, the FoM related to the loop filter noise improves, whereas at lower supplies, the FoM related to the quantisation noise improves. As a result, the overall FoM of the DSM reaches an optimum at a particular supply. The supply voltage with the best FoM of the DSM is derived with the supply‐scaling FoM of the loop filter and quantisers. For an equal FoM of the loop filter and quantisers at a supply V, the optimal supply voltage is 0.66 V.
Direction of arrival estimation using combined coprime and nested array
Authors: Li Jianfeng , Li Yunxiang , Zhang Xiaofei
Published: February 2019

A combined coprime and nested array geometry is designed and a corresponding direction of arrival (DOA) method is proposed. The proposed array has three subarrays, where two are prototype coprime subarrays, and both of them are nested to the third one. Then the vectorisations of two covariance matrices yield two virtual coprime subarrays, which show a much larger aperture compared to the physical ones. Thereafter, through Toeplitz matrix reconstruction and root multiple signal classification, two coprime estimations are obtained and they are combined to obtain the final unique DOA estimation. Multiple analysis and simulations verify that the proposed method achieves larger aperture, better DOA estimation accuracy and higher angular resolution compared to other coprime array‐based methods.
3 GHz, 1 mW inverter‐based TIA with capacitive feedback for enhanced gain and sensitivity in VLC applications
Authors: Li Xianbo , Patrick Yue C.
Published: February 2019

In this Letter, a novel inverter‐based trans‐impedance amplifier (TIA) with enhanced gain and sensitivity is presented for Gb/s visible light communication (VLC). By employing capacitive feedback with a large negative equivalent capacitance to reduce the TIA input capacitance, the proposed TIA achieves a trans‐impedance gain of 89.4 dBΩ with 5.7 dB improvement and an input referred noise current of 0.43 µArms with 1.8 dB improvement when compared to a reference TIA without capacitive feedback. Both the proposed TIA and the reference TIA have the same −3 dB bandwidth (BW) of 3 GHz and the same power consumption of 1 mW, and they are designed with a 40 nm CMOS process.
Shape geodesics for robust sign language recognition
Authors: Nasreddine Kamal , Benzinou Abdesslam
Published: February 2019

In this study, a novel method of pattern recognition for static gesture recognition is proposed. To deal with this application, the authors should tackle the problem of low variability among shape classes in the gestures databases. The authors’ method is based on robust registration and shape geodesics in shape space with a preliminary step of pose estimation accelerating the processing time. The different gestures are considered individual points in a non‐linear shape space. Similarity between any two considered shapes can be measured by a distance metric on the shape space. For shape comparison, three distances with and without robust norm are proposed and evaluated for the target application. To cope with low shape variability among classes, the best scheme is to use robust norm in shape matching but not in shape comparison. Experiments are conducted on reference databases used in the literature to evaluate static gesture recognition. These experiments show the outperformance of the proposed scheme compared to state‐of‐the art methods.
Machine‐learning regression in evolutionary algorithms and image registration
Authors: Spanakis Constantinos , Mathioudakis Emmanouil , Kampanis Nikos , Tsiknakis Manolis , Marias Kostas
Published: February 2019

Evolutionary algorithms have been used recently as an alternative in image registration, especially in cases where the similarity function is non‐convex with many local optima. However, their drawback is that they tend to be computationally expensive. Trying to avoid local minima can increase the computational cost. The purpose of authors’ research is to minimise the duration of the image registration process. This paper presents a method to minimise the computational cost by introducing a machine learning–based variant of Harmony Search. To this end, a series of machine‐learning regression methods are tested in order to find the most appropriate that minimises the cost without degrading the quality of the results. The best regression method is then incorporated in the optimisation process and is compared with two well‐known ITK image registration methods. The comparison of authors’ image registration method with ITK concerns both the quality of the results and the duration of the registration experiments. The comparison is done on a set of random image pairs of various sources (e.g. medical or satellite images), and the encouraging results strongly indicate that authors’ method can be used in a variety of image registration applications producing quality results in significantly less time.
Survey on hardware implementations of visual object trackers
Authors: El‐Shafie Al‐Hussein A. , Habib Serag E.D.
Published: February 2019

Visual object tracking is an active topic in the computer vision domain with applications extending over numerous fields. The main sub‐tasks required to build an object tracker (e.g. object detection, feature extraction and object tracking) are computationally intensive. Also, the real‐time operation of the tracker is indispensable for almost all of its applications. Therefore, complete hardware or hardware/software co‐design approaches are pursued for better tracker implementations. This study presents a literature survey of the hardware implementations of object trackers over the last two decades. Although several tracking surveys exist in the literature, a survey addressing the hardware implementations of the different trackers is missing. The authors believe this survey would fill the gap and complete the picture with the existing surveys of how to design an efficient tracker and point out the future directions researchers can follow in this field. They highlight the lack of hardware implementations for state‐of‐the‐art tracking algorithms as well as for enhanced classical algorithms. They also stress the need for measuring the tracking performance of the hardware‐based trackers. Additionally, enough details of the hardware‐based trackers need to be provided to allow a reasonable comparison between the different implementations.
Identification and location of PIM faults in radio‐frequency circuits with multiple coaxial connectors using a neural network approach
Authors: Jin Qiuyan , Gao Jinchun , Flowers George Timothy , Wu Yongle , Bi Lingyu , Ji Rui
Published: February 2019

Coaxial connectors are widely used in radio‐frequency circuits and are a major non‐linear source of passive intermodulation (PIM), especially when they are subjected to environmental degradation. Accordingly, an effective and accurate method to locate the position of the PIM source in a communication system is of substantial value. By analysing the characteristics of different connectors, equivalent circuit models were developed to generate dynamic harmonics powers. On the basis of transmission line theory and simulations, the features of the IM products (IM3, IM5, and IM7) in a series circuit with the selected PIM source points were investigated. Using this information, a PIM fault diagnosis method for coaxial connectors in a circuit was developed employing a neural network. The IM products powers were obtained as feature parameters using a scattering parameter simulation of series circuit for three different connectors. Simulations were then conducted to generate training and testing samples. Finally, using the back‐propagation neural network algorithm, the fault modes were classified and the results show diagnosis accuracy was 96.72%.
Extremely compact EBG‐backed antenna for smartwatch applications in medical body area network
Authors: Rano Dinesh , Hashmi Mohammad
Published: February 2019

This paper presents design of a compact interdigital electromagnetic band gap unit cell (IDE) for wearable applications in the medical body area network (MBAN) band. The uniqueness of the proposed cell is in its ability to achieve lower resonant frequency in spite of very compact size of 14.3 mm × 14.5 mm. The cell has adjacent fingers connected in such a way that the net inductance contributed by the metallic strips increases and this aids in the reduction of resonant frequency. An equivalent lumped circuit model supports the analysis of the proposed cell. The evaluation of the developed model is assessed by comparing the reflection phase response obtained from the circuit model and full wave analysis. The proposed design, even though slightly asymmetric, possess polarisation stability and this has been validated using the reflection phase parameter for a plane wave polarised along x ‐and y‐axes. Subsequently, a reflector consisting of 2 × 2 IDE‐unit cell to be integrated with monopole antenna of overall size 36 mm × 38 mm × 3.12 mm is designed. The design exhibits a very good agreement between the experimental and the simulated results whereby it is able to provide gain and efficiency of 5.3 dB and 85% respectively at the MBAN frequency.
Interleaved boost converter for global maximum power extraction from the photovoltaic system under partial shading
Authors: Farh Hassan M.H. , Eltamaly Ali M. , Al‐Saud Mamdooh S.
Published: February 2019

Partial shading (PS) condition has a negative effect on the shaded photovoltaic (PV) modules/arrays itself. In addition, it reduces the output power generated considerably. The PV system configuration represents one of the effective solutions to alleviate the PS effects and extract the global maximum power (GMP) available from the partially shaded PV (PSPV) system. This study introduces a detailed performance analysis and comparisons of four proposed PV system configurations [module integrated converter (MIC), multi‐strings interfaced interleaved boost converter (MSIBC), multi‐arrays interfaced IBC and single array single converter (SASC)] in terms of output power generated and mismatch loss (MML) index. The selection of the best PV system configuration, which not only mitigates the PS effects but also extracts the GMP available from the PSPV system, depends on a trade‐off between the generated power, cost and complexity before judging which one is preferable. Although the MIC PV system has the highest output power generated (33 kW) and MML (100%), it increases the PV system complexity. Whereas, MSIBC has the second highest output power generated (28 kW) and MML compared to MIC. SASC has the lowest generated power and MML among the four configurations. The finding proves that MSIBC has superior performance compared to the other PV system configurations considering both the technical and economic assessment.
Grade point average assessment for metaheuristic GMPP techniques of partial shaded PV systems
Authors: Eltamaly Ali M. , Farh Hassan M.H. , Al‐Saud Mamdooh S.
Published: February 2019

Photovoltaic (PV) maximum power point tracker (MPPT) is compulsory in PV systems to improve its output power and efficiency. Conventional techniques can track the maximum power under uniform irradiances efficiently and accurately. Nevertheless, in case of partial shading conditions where multiple peaks are generated, these conventional techniques may stick at any local peak of the P–V curve of the PV energy systems. Metaheuristic techniques have been applied to PV energy systems to overcome this limitation, where most of these techniques can catch the global MPP (GMPP) easily and efficiently. In case of dynamic change of partial shading, most of these techniques need reinitialisation to disperse the search agents to look again for a new position and value of GMPP. This study introduces a brief description, assessment and evaluation for these techniques. In addition, it proposes a novel assessment criterion based on grade point average for evaluating and ranking the 20 famous metaheuristic and hybrid GMPP techniques. This evaluation methodology can help researchers, designer and decision maker to choose the best option for MPPT of dynamic change of partially shading PV energy systems.
Towards emulating cosmic shear data: revisiting the calibration of the shear measurements for the Kilo-Degree Survey
Authors: Kannawadi Arun , Hoekstra Henk , Miller Lance , Viola Massimo , Fenech Conti Ian , Herbonnet Ricardo , Erben Thomas , Heymans Catherine , Hildebrandt Hendrik , Kuijken Konrad , Vakili Mohammadjavad , Wright Angus H.
Published: February 2019

Exploiting the full statistical power of future cosmic shear surveys will necessitate improvements to the accuracy with which the gravitational lensing signal is measured. We present a framework for calibrating shear with image simulations that demonstrates the importance of including realistic correlations between galaxy morphology, size, and more importantly, photometric redshifts. This realism is essential to ensure that selection and shape measurement biases can be calibrated accurately for a tomographic cosmic shear analysis. We emulate Kilo-Degree Survey (KiDS) observations of the COSMOS field using morphological information fromHubbleSpace Telescope imaging, faithfully reproducing the measured galaxy properties from KiDS observations of the same field. We calibrate our shear measurements fromlensfit, and find through a range of sensitivity tests thatlensfit is robust and unbiased within the allowed two per cent tolerance of our study. Our results show that the calibration has to be performed by selecting the tomographic samples in the simulations, consistent with the actual cosmic shear analysis, because the joint distributions of galaxy properties are found to vary with redshift. Ignoring this redshift variation could result in misestimating the shear bias by an amount that exceeds the allowed tolerance. To improve the calibration for future cosmic shear analyses, it will also be essential to correctly account for the measurement of photometric redshifts, which requires simulating multi-band observations.
Maitrise de la salinité des eaux d'irrigation pour la viticulture
Authors: Escudier J.-L. , Gillery B. , Ojeda H. , Etchebarne et F.
Published: February 2019

Même si la vigne reste parmi les plantes cultivées une des plus économes en eau, se pose maintenant la question de la disponibilité et de l'accessibilité à la ressource en eau naturelle de qualité: eaux souterraines (infiltration, nappes), eaux de surface stagnantes (lacs, retenues de barrages) ou en écoulement (rivières, fleuves), eaux de mer, eaux usées traitées (REUT). Certaines de ces eaux peuvent contenir des composés d'intérêts nutritionnels pour les plantes, mais aussi être riches en sels dissous. L'objet de cette communication est d'étudier les technologies permettant d'affiner la teneur en sel de l'eau d'irrigation pour la vigne, quel que soit son origine et son niveau initial. Les techniques membranaires, osmose inverse, nanofiltration et électrodialyse sont ainsi comparées techniquement et évaluées économiquement. Les unes, nanofiltration et osmose inverse, à partir de membranes poreuses ou denses sous pression, consiste en une séparation de quasi tous les éléments dissous de l'eau (anions, cations, mais y compris les nutriments azotés, et minéraux) et ce quel que soit, pour l'osmose inverse, la salinité de l'eau initiale (e.g. eau de mer). L'autre l'électrodialyse, à partir de membranes denses ne filtre pas l'eau, mais extrait une quantité pilotable en ligne, de sels dissous (Na+et Cl−en particulier sélectionnables) sous l'effet d'un champ électrique, afin de l'adapter aux sols ou plantes concernés
Effects of sulfur dioxide on wine made with sulfitic maceration
Authors: Jardim G.V. , Zigiotto L. , Machado W. , Marcon Â.R.
Published: February 2019

Sulfitic maceration is part of a technique used in large companies to store must through the superdosing of sulfur dioxide added after the destemming of the grapes. The objective of this study was to analyze the physico-chemical characteristics of the wines elaborated by sulfitic maceration. The study was conducted at the Federal University of Pampa (UNIPAMPA), Campus Dom Pedrito, RS, Brazil. Three vinifications (identified by treatments 1, 2 and 3) were performed with 3 replicates each. The grapes used were the cultivar Alicante Bouschet. Treatment 1 underwent the same procedures as treatment 2, except for the dosage of 1400 mg.L−1 of added sulfur dioxide. The grapes were destemmed, crushed and macerated for 2 days and before fermentation started, the must was heated to remove SO2. In the treatment 3 a traditional maceration was carried out for 5 days. The physicochemical characteristics of the wines were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and the results were analyzed by statistical analysis of comparison of averages. The color intensity of treatment 2 showed no significant difference in relation to the treatment 3, demonstrating that with 2 days of sulphitic maceration, occurs a color extraction similar to a traditional 5-day maceration.
Oenological attributes of the yeast Hanseniaspora vineaeand its application for white and red winemaking
Authors: Martin V. , Fariña L. , Medina K. , Boido E. , Dellacassa E. , Mas A. , Carrau F.
Published: February 2019

Flavour and some compounds associated with wine colour are known to be yeast strain-dependent. These metabolites are important for the sensory quality of wines, studies searching for increase aroma and color are a key area today in winemaking. The aim of this work was to study the oenological potential of the two main strains of Hanseniaspora vineae,native to Uruguay to better understand their successful application at winery level. It is known that these strains contribute with extracellular proteases and β-glucosidase enzyme activities that might increase cell lysis and flavor depending in grape varieties. Application and nutrient management of the process of these strains in production of white wines (Chardonnay, Macabeo and Petit Manseng) and red wine Tannat are discussed. Wines were evaluated to determine the volatile compounds composition and their effect compared to conventional processes. Low production of short and medium chain fatty acids and ethyl esters, and high production of acetate esters and isoprenoids are found compared to S. cerevisiaestrains. The most outstanding characteristic of the species H. vineaewas the production of benzenoids, phenylpropanoids and acetate esters. This behavior was reflected in the sensory evaluation, where all the fermentations performed with H. vineaewere considered superior compared to Saccharomyces cerevisiaewine strains.
Barrel-to-barrel variation of phenolic and mineral composition of red wine
Authors: Pilet A. , Sousa R.B. de , Ricardo-da-Silva J.M. , Catarino S.
Published: February 2019

The aim of the present work was to evaluate the effect of barrel-to-barrel variability on chemical characteristics of red wine. An experimental trial was carried out involving two red wines from the Portuguese DO Dão and independent replicates of French oak barrels (Quercus sessilifloraSalisb.) from three different cooperages. After six months of aging, comprehensive chemical characterization of the wines took place: general physical-chemical analysis by FTIR, phenolic composition and chromatic characteristics, major mineral elements (K, Mg, Ca, Na, and Fe) by flame atomic absorption spectrometry (FAAS), minor and trace elements (Li, Be, Ti, Mn, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Cs, Ba, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Tl, Pb, and U) by inductively coupled plasma mass spectrometry (ICP-MS). In respect to barrel effect, significant differences between replicates were observed for phenolic composition, especially polymerized pigments, flavonoids and color intensity. Regarding major, minor and trace elements, no significant differences were observed between barrel replicates with exception of iron and copper.
The origin of pinking phenomena in white wines: An update
Authors: Cosme F. , Andrea-Silva J. , Filipe-Ribeiro L. , Moreira A.S.P. , Malheiro A.C. , Coimbra M.A. , Domingues M.R.M. , Nunes F.M.
Published: February 2019

Pinking is the term used to describe the appearance of a salmon-red blush color that may appear in bottled white wines, produced solely from white grape varieties. It is perceived as an undesirable phenomenon for both, wine consumers and winemakers. Although with seasonal and regional variations, the pinking has been observed worldwide, with predominance in white wines produced fromVitis viniferaL. grape varieties. The pinking origin of Síria white grapes has been studied in detail and it has been shown that the origin of the pinking phenomenon in white wines fromVitis viniferaL. Síria grape variety are anthocyanins, mainly malvidin-3-O-glucoside. The minimum amount of anthocyanins needed for the visualization of the wine pink color was 0.3 mg/L. Further studies in other white monovarietal wines that occasionally suffer from this defect, like white wine from Malvasia Fina grape variety, Loureiro grape variety, Sauvignon Blanc grape variety and Albariño grape variety, have shown that this wines produced from this grape varieties also show low amounts of anthocyanins, mainly malvidin-3-O-glucoside. These results show that the presence of low but visible detectable anthocyanins as the origin of the pinking phenomena is also observed in other white grape varieties besides that of Síria.
Impiego di antiossidanti per limitare la comparsa del difetto di luce durante la shelf-life
Authors: Fracassetti D. , Limbo S. , Tirelli A.
Published: February 2019

Il difetto di luce è un'alterazione che può avvenire nel vino bianco dovuto alla formazione di composti solforati, quali metantiolo (MeSH) e dimetildisolfuro (DMDS). Tali composti derivano dalle reazioni foto-ossidative che coinvolgono la riboflavina (RF), un composto fotosensibile, e la metionina (MET). È stato recentemente osservato che l'aggiunta di tannini di legno limita la comparsa del difetto in soluzione modello. Non è stata ancora chiarita l'evoluzione del difetto di luce nel corso della shelf-life. In questo studio sono stati valutati i fenomeni foto-ossidativi in soluzione modello dopo 24 mesi di conservazione. La soluzione modello è stata addizionata di RF e MET, e di antiossidanti, quali anidride solforosa, glutatione e tannino di castagno, singolarmente ed in combinazione, ed esposta alla luce. Come atteso, RF è stata degradata con la luce in tutte le condizioni saggiate. Al contrario, la diminuzione di MET è dipendente dalla tipologia di antiossidante aggiunto, anche nei campioni conservati al buio. L'aggiunta degli antiossidanti limita la formazione del difetto di luce come dimostra il minore livello dei composti solforati, MeSH, DMDS and dimetil trisolfuro ed il minor punteggio ottenuto dall'analisi sensoriale. Gli antiossidanti testati possono svolgere un'azione protettiva contro la comparsa del difetto di luce.
Efecto del uso de hidrolizado enzimático de proteína de levadura sobre la fermentación y el perfil sensorial del vino
Authors: Valencia P. , Rojas P. , Urbina C. , Urtubia A.
Published: February 2019

Se evaluó el uso de proteínas de levaduras como fuente de nitrógeno orgánica para la fermentación en reemplazo del diaminofosfato (DAP). Se utilizaron Saccharomyces cerevisiae autoclavadas y posteriormente hidrolizadas con 6.75 mAU/g de subtilisina a pH 8.0 y 50 ∘C hasta grados de hidrólisis de 5% y 15%. Se fermentó mosto de Cabernet sauvignon con Saccharomyces cerevisiae a 28 ∘C y pH 3.5, utilizando como fuente de nitrógeno DAP (control) e hidrolizados proteicos de levadura (tratamientos). Se realizó un seguimiento de las fermentaciones midiendo ∘Brix, azúcares reductores y grado alcohólico final. El grado alcohólico resultó en promedio 12 ∘, mientras que los azúcares residuales fueron menores a 2 [g/L]. No se observaron diferencias significativas entre el control y los tratamientos, lo cual implica que durante las fermentaciones con hidrolizado proteico de levaduras no hubo deficiencia de nitrógeno, por lo que se infiere que los péptidos del hidrolizado fueron metabolizados por las levaduras. Se realizaron análisis sensoriales y de compuestos volátiles de diferentes vinos elaborados con DAP e hidrolizado proteico de levaduras como fuente de nitrógeno. El uso de hidrolizado proteico de levaduras generó cambios significativos en el perfil de alcoholes superiores y ésteres del vino en comparación con el uso de DAP. El panel organoléptico detectó un mayor dulzor y menor acidez en los vinos que usaron hidrolizado en comparación con los producidos con DAP. La utilización de hidrolizado enzimático de proteínas de levadura como fuente de nitrógeno orgánica en la fermentación del vino es técnicamente factible y además beneficiosa para las propiedades organolépticas del vino.
Développement de nouvelles applications pour l'utilisation de protéases en œnologie
Authors: Ducruet J. , Cahuzac R. , Silvestri A.-C. , Roeslé J. , Bach B. , Cléroux M. , Koestel C. , Laurenzini F. , Roesti J.
Published: February 2019

Depuis les années 70, les préparations enzymatiques sont des auxiliaires technologiques d'origine biologique de plus en plus appréciées pour l'aide qu'elles apportent dans les différentes étapes de la vinification (Débourbage, pressurage, macération, filtration et stabilisation microbiologique). Les activités utilisables en œnologie sont décrites par le règlement européen 1493/1999 et les résolutions œnologiques 11–18/2004 de l'OIV. A ce jour, les protéases ne font pas partie des activités enzymatiques autorisées car jugées inefficaces dans le milieu hostile qu'est le vin. Plus récemment, il a été démontré que l'utilisation d'une aspergillopepsines couplée de la flash pasteurisation permettait l'hydrolyse complète des protéines thermo-instables des vins blancs à l'échelle pilote et industrielle.

L'objectif de ce travail est d'explorer de nouvelles applications œnologiques à l'utilisation de protéases. Pour cela, 4 protéases industrielles ont été testées sur l'amélioration de la filtrabilité des vins et l'élevage sur lies d'un vin rouge et un vin blanc. Ce travail a permis de mettre en évidence que l'utilisation de protéase pouvait améliorer sensiblement la filtrabilité des vins. L'amélioration observée est plus importante avec un test de filtrabilité (Vmax sur membrane 0.45 μm) qu'en filtration tangentielle (membrane céramique 0.2 μm). Enfin, en l'absence de flash pasteurisation les protéases ne semblent pas avoir d'effet sur la filtrabilité ou l'élevage sur lies des vins.

Mots clés :Enzyme, Protéase, filtrabilité, filtration tangentielle, vin.
Effect of the extent of ethanol removal on the volatile compounds of a Chardonnay wine dealcoholized by vacuum distillation
Authors: Petrozziello M. , Panero L. , Guaita M. , Prati R. , Marani G. , Zinzani G. , Bosso A.
Published: February 2019

“Beverages obtained from the partial dealcoholization of wine” are those drinks whose final alcoholic degree after dealcoholization is lower than that of a wine and higher than or equal to 0.5% v/v. When the total alcoholic degree is lower than 0.5% v/v the denomination is “Beverages obtained from the dealcoholization of wine”.

The practices to be authorized for the production of these drinks with the dealcoholized wine fractions are currently being studied at OIV. The characterization of the composition of these fractions is essential to identify the necessary corrective practices.

The present work was aimed at monitoring the losses of the main volatile compounds of a Chardonnay wine with the proceeding of the dealcoholization process by vacuum distillation. The wine was subjected to total dealcoholization, and during the process the evaporated fractions, re-condensed at 9 ∘C, were collected in aliquots of 1.25 L each. The ethanol content of each fraction was measured, and for the first 20 fractions the content in volatile compounds was determined with GC-MS.

The results show that the losses of volatile compounds during the dealcoholization process follow different trends depending on the molecules considered. The most volatile compounds, generally with the lowest perception thresholds, were mainly present in the first evaporated fractions. The greatest losses concerned isoamylacetate, ethyl hexanoate and ethyl octanoate.

Conversely, a greater number of molecules were present at similar concentrations in the different fractions, and their losses followed a linear or sometimes exponential trend: in particular, these compounds included n-hexanol, 2-phenylethanol, diethyl succinate and medium chain fatty acids (hexanoic, octanoic and decanoic acids).

In the wine dealcoholized at 3.36% v/v (loss of ethanol equal to 7.43% v/v, corresponding to the 20th and last recondensed fraction), some volatile compounds were no longer detectable or quantifiable; in particular, these compounds were isoamylacetate, ethylhexanoate, hexylacetate, n-hexanol and other alcohols with 6 carbon atoms and ethyl octanoate.

Other compounds, such as hexanoic, octanoic and decanoic acids, and, in particolar, β-phenylethanol, benzylic aalcohol and γ-butyrolactone, underwent lower percentage losses than those of ethanol. The dealcoholization process can therefore deeply modify the original aromatic profile of the wines, intervening on the absolute concentration and on the relative ratios of the single molecules.
Detección de levaduras y bacterias ácido lácticas nativas de diferentes cultivares chilenos: Potenciales especies para la producción de vinos reducidos en alcohol
Authors: Franco W. , Valencia P. , Ramírez C. , Urtubia A.
Published: February 2019

En este estudio se caracterizó la microbiota natural (levaduras y bacterias ácido lácticas) observada durante la fermentación espontánea de variedades de uva de Chile, con el fin de evaluar su potencial para producir vinos con menor contenido de etanol. El potencial de fermentación de las levaduras seleccionadas se determinó en términos de consumo de azúcar y producción de etanol. Las cepas con potencial para producir vinos reducidos en etanol se estudiaron adicionalmente en inoculaciones secuenciales con Saccharomyces cerevisiae. Se identificaron nueve especies no Saccharomyces y solo tres géneros de bacterias ácido lácticas. Durante las etapas finales de fermentación, S. cerevisiae y L. mesenteroides fueron dominantes, mientras que solo Candida, Metchnikowia, Torulaspora y Lachancea spp. se observaron después de 14 días de fermentación. La fermentación de cultivo puro con cepas aisladas seleccionadas mostró aproximadamente un 50% de utilización de azúcar, con una producción de etanol que varió desde 6.25 a 9.25% v/v. Nuestros resultados sugieren que las levaduras nativas R. glutinis, M. pulcherrima y H. uvarum, aisladas en este estudio, son potenciales para producir vinos reducido en etanol. Sin embargo, se necesitan más estudios sobre la contribución en sabor y el aroma.
Evaluation ofSaccharomyces pastorianusimpact to Sauvignon blanc chemical & sensory profile compared to different strains ofS. cerevisiae/bayanus
Authors: Troianou V. , Toumpeki C. , Dorignac E. , Kogkou C. , Kallithraka S. , Kotseridis Y.
Published: February 2019

Enhancing flavors and/or improving fermentation parameters through the use of different species of yeast strains is nowadays a frequent challenge in winemaking research, especially for aromatic varieties such as Sauvignon Blanc. In this work, the aim was to focus on the impact of a species not already studied in wine:Saccharomyces pastorianus. Twenty-two fermentations were conducted on a Sauvignon Blanc must by addition of different strains and mixtures of them by using two different inoculation temperatures. The must was inoculated in cold condition with two similar mixtures ofS. pastorianus1 or 2 (70%) andS. bayanus(30%), withS. pastorianus1 or 2 alone, with the correspondentS. bayanusalone and with two otherS. cerevisiae1 and 2 alone as well. For classic condition, the must was inoculated with only one mixtureS. pastorianus1 (70%) /S. bayanus(30%), and respectively withS. pastorianus1,S. bayanusandS. cerevisiae2 alone. Samples were taken all along the fermentations for both conditions in order to check chemical and microbial analyses as well as yeast implantations. The final wines were analysed for alcohol, glucose, fructose, all other classical wine analysis as well as for acetate esters, and higher alcohols. The results underlined that for bothS. pastorianus1 andS. pastorianus2 strains, the production of acetic acid was zero in cold condition and really low (0.09 g/l) for classic condition regardingS. pastorianus1. As a consequence,Saccharomyces pastorianusseems to be highly interesting for winemaking, alone or in co-inoculation withS. bayanus.
Microbial diversity in grape musts from Austrian and South African grape varieties and regions
Authors: Bagheri B. , Philipp C. , Horacek M. , Bauer F.F. , Setati M.E.
Published: February 2019

Vitis vinifera is one of the most widely planted crops and holds important economic value in South Africa and Austria. Grapes obtained from this plant harbour a complex fungal community which plays a crucial role in the wine fermentation process and influences wine flavour and aroma. For many years the contributions of the natural yeasts has been eclipsed by the use of active dry yeast (ADY) inoculant, mainly of the species Saccharomyces cerevisiae. However, recent studies show a growing interest in deciphering the natural microbial diversity and in promoting its persistence during fermentation in order to enhance wine typicity. The current preliminary study aims to provide a first broad assessment of the fungal community fingerprint of different grape varietals from different wine producing areas in Austria and South Africa through Automated Ribosomal Intergenic Spacer Analysis (ARISA). The ARISA profiles separated the samples according to country of origin, and suggested some regional and varietal separation within each country. Future work will evaluate the contribution of these fungal communities to wine chemical composition and sensorial distinctness.
Investigation of geographic origin of wine from border regions: Potential limitations and possibilities of different analytical methods and combinations of methods to identify the correct side of the border
Authors: Horacek M. , Kolar K. , Hola M. , Tobolkova B. , Vaculovic T. , Philipp C. , Marosanovic B. , Mikes O. , Polovka M. , Lojovic M. , Belajova E. , Daško L. , Jankura E. , Eder P.
Published: February 2019

In the presented project the investigation on discrimination of geographic origin of wine in from border areas is carried out. Authentic wine samples from the border areas of Austria, Czech Republic, Slovakia (and from Serbia) are investigated and compared by applying different physico-chemical methods (e.g. IRMS, NMR, ICP-MS, ICP-OES, EPR, HPLC, UV-VIS, etc.). The comparison of the data sets from the participating countries and the different applied methods will show, to which extent a differentiation can still be achieved in the border areas of the respective countries, which methods prove most efficient and sensitive and if a combination of methods will lead to an increased sensitivity. Furthermore, we also investigate the causes for the potential differentiation, which might be environmentally determined, due to different agricultural and/or enological practices. Results from the first investigated vintage 2016 show a good separation of the respective geographic origins by isotope ratios and element concentrations as well as by other parameters. The relevant parameters for differentiation now have to be critically evaluated to exclude potential lab influences.
Revealing full chemical forms of lead in wine with combined XRF-NMR technologies
Authors: Herbert-Pucheta J.E. , Ortega Q.U. , Zepeda-Vallejo L.G. , Milmo-Brittingham D. , Maya G.P. , Aragón L.A.O. , Castillo E. , González F.R. , Pino-Villar C. , García R.G.
Published: February 2019

Since 1953, The World Organization of Vine and Wine (OIV) Member States have reduced the lead maximum limits (ML) in wines, down to 0.05 mg/L (2018). Evidently, this ML value is too restrictive for wine industry as it excludes from international market a significant portion of wine production. Currently, the Codex Committee on Contaminants in Foods and OIV had recognized the value of gathering robust and novel data to better assess the best lowest ML for wine industry. Currently, there is not a direct statement within international reference documents, of which chemical form of lead must be controlled and/ or reduced. This work presents for the first time a method combining Energy Dispersive X-Ray analysis (EDAX) and Nuclear Magnetic Resonance (NMR) spectroscopies in order to determine presence and concentrations of major and trace elements of lead and other element moieties in wine that can allow to better redefine lead's ML. By identification of K, L, M, radiation shells with additional αβi labelling of lead's major and minor components with semi-quantitative XRF, combined with chemical-shift analysis of inorganic Pb4+, Pb2+ and/or organo-lead within wine samples, we propose a full discrimination framework to disentangle and quantify different chemical forms of lead.
Mass-spectrometric study on13C/12C carbon and18O/16O oxygen stable isotopes distributions in grapes and wines from the Black Sea regions
Authors: Kolesnov A. , Zenina M. , Tsimbalaev S. , Tereshenko G. , Torshina L. , Anikina N. , Gnilomedova N. , Gerzhikova V. , Egorov E. , Guguchkina T. , Prakh A. , Antonenko M.
Published: February 2019

The present study continues the 2015–2016 research project on biological characteristics of stable isotopes fractionation in grapes taking into account the agro-climatic growth conditions of this representative of the C3-pathway of photosynthesis group of plants in different geographical Black Sea regions. The first parts of the project were presented at the 39th and 40th Congresses of OIV in Bento Gonçalves (Brazil) and Sofia (Bulgaria). The scientific data on compositions of13C/12C carbon and18O/16O oxygen stable isotopes in carbohydrates, organic acids, and intracellular water were obtained for grapes of 2015–2016 growing seasons in the four areas of the Crimean peninsula as well as in several areas of the Don Basin and the Western Caspian region. This report presents the results of the 2017 season study of13C/12C carbon and18O/16O oxygen stable isotopes in carbohydrates and intracellular water of 12 red and white grape varieties (Aligote, Rkatsiteli, Sauvignon Zeleny, Chardonnay, Cabernet Sauvignon, Sauvignon Blanc, Merlot, Risling, Pinot Noir, Cabernet Franc, Sira, Krasnostop) as well as in ethanol of wines made from corresponding grapes from the Crimean Peninsula and South-West Coast of the Greater Caucasus. To measure the ratio of carbon isotopes13C/12C in grape (must) carbohydrates and wine ethanol the Flash-Combustion technique (FC-IRMS/SIRA) has been used, while the method of isotopic equilibration (EQ-IRMS/SIRA) has been used for the measurement of18O/16O oxygen isotopes ratio in the intracellular water of grapes (must) and in the water fraction of wine. The GC-Combustion technique (GC-IRMS/SIRA) has been used for the first time to measure the carbon isotopes13C/12C distribution in ethanol of studied wines. It has been found that the δ13CVPDBvalues for carbohydrates of red and white grape varieties as a result of biological fractionation of carbon isotopes in the agro-climatic conditions of plant growth (2017 season) for the studied geographical areas formed the following quantitative ranges: from − 26.72 to − 23.35‰ (the Crimean Peninsula) and from − 25.92 to − 23.87‰ (South-West Coast of the Greater Caucasus). The δ13CVPDBvalues for wine ethanol are in the following ranges: from − 28.15 to − 24.47‰ (the Crimean Peninsula) and from − 27.29 to − 25.78‰ (South-West Coast of the Greater Caucasus). The δ18OVSMOWvalues in intracellular water of grapes of the 2017 season range from − 1.24 to 2.17‰ (the Crimean Peninsula) and from 1.08 to 4.09‰ (South-West Coast of the Greater Caucasus). The results of this study show, in comparison with the results of studies of the 2015 and 2016 seasons, a decrease in the δ13CVPDBvalues for carbohydrates of grapes and ethanol of wine, which is explained by the changed climatic conditions of grapes growing in the vegetation period of 2017.