| 1. |
- Danner, L., et al.
(författare)
-
Dynamic viscosity levels of dry red and white wines and determination of perceived viscosity difference thresholds
- 2019
-
Ingår i: American Journal of Enology and Viticulture. - : American Society for Enology and Viticulture. - 0002-9254 .- 1943-7749. ; 70:2, s. 205-211
-
Tidskriftsartikel (refereegranskat)abstract
- Wine mouthfeel significantly contributes to the overall sensory perception and quality of wines. However, the influence of dynamic viscosity on the mouthfeel of dry table wines is still not fully understood. The three objectives of this study were to 1) determine the perceived viscosity difference threshold in wine using wine/xanthan gum solutions, 2) measure dynamic viscosity levels of Australian commercial dry Shiraz and Chardonnay table wines, and 3) investigate in wine samples the relationship between dynamic viscosity and chemical parameters, specifically, residual sugar, ethanol, and pH. A wine viscosity difference threshold value of 0.138 mPa·sec at 20°C was determined by ascending two-alternative forced-choice difference threshold tests with a sensory panel (n = 45). The dynamic viscosity for 34 commercial Chardonnay wines at 20°C ranged from 1.448 mPa·sec to 1.529 mPa·sec, and from 1.488 mPa·sec to 1.695 mPa·sec for 29 Shiraz wines. These results indicate that on the basis of the determined threshold values, tasters could likely differentiate wines in terms of viscosity within the viscosity range of this sample set of Shiraz, but not Chardonnay, wines. Furthermore, significant correlations between dynamic viscosity and ethanol concentration, but not for pH and residual sugar, were found for both varieties, indicating that ethanol may have been the main compositional factor that increased dynamic viscosity in commercial dry wines.
|
|
| 2. |
- Jiang, Shangsong, et al.
(författare)
-
Cutting Force and Surface Roughness during Straight-Tooth Milling of Walnut Wood
- 2022
-
Ingår i: Forests. - : MDPI. - 1999-4907. ; 13:12
-
Tidskriftsartikel (refereegranskat)abstract
- Walnut (Juglans regia L.) is widely used in wood furnishings, and machinability is a key factor for improving product quality and enterprise benefits. This work focused on the influence of the rake angle, depth of cut, and cutting speed on the cutting force and machined surface roughness during the straight-tooth milling of walnut. On the basis of the experimental findings, a mathematical model was created using a response surface methodology to determine the relationship between the cutting force and the cutting conditions, as well as the relationship between the surface roughness and the cutting conditions. Variance analysis was used to study the significant contributions of the interactions of various factors and two-level interactions to the cutting force and surface roughness. The optimized combination of milling conditions, resulting in lowest cutting force and surface roughness, was determined to be a rake angle of 5°, a depth of cut of 0.6 mm, and a cutting speed of 45 m/s.
|
|
| 3. |
- Jiao, Xiang, et al.
(författare)
-
Comparative analysis of nonlinear growth curve models for Arabidopsis thaliana rosette leaves
- 2018
-
Ingår i: Acta Physiologiae Plantarum. - : Springer. - 0137-5881 .- 1861-1664. ; 40:6
-
Tidskriftsartikel (refereegranskat)abstract
- As a model organism, modeling and analysis of the phenotype of Arabidopsis thaliana (A. thaliana) leaves for a given genotype can help us better understand leaf growth regulation. A. thaliana leaves growth trajectories are to be nonlinear and the leaves contribute most to the above-ground biomass. Therefore, analysis of their change regulation and development of nonlinear growth models can better understand the phenotypic characteristics of leaves (e.g., leaf size) at different growth stages. In this study, every individual leaf size of A. thaliana rosette leaves was measured during their whole life cycle using non-destructive imaging measurement. And three growth models (Gompertz model, logistic model and Von Bertalanffy model) were analyzed to quantify the rosette leaves growth process of A. thaliana. Both graphical (plots of standardized residuals) and numerical measures (AIC, R2 and RMSE) were used to evaluate the fitted models. The results showed that the logistic model fitted better in describing the growth of A. thaliana leaves compared to Gompertz model and Von Bertalanffy model, as it gave higher R2 and lower AIC and RMSE for the leaves of A. thaliana at different growth stages (i.e., early leaf, mid-term leaf and late leaf).
|
|
| 4. |
- Kang, W., et al.
(författare)
-
Chemical and sensory impacts of Accentuated Cut Edges (ACE) grape must polyphenol extraction technique on shiraz wines
- 2020
-
Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 9:8
-
Tidskriftsartikel (refereegranskat)abstract
- Accentuated Cut Edges (ACE) is a recently developed grape must extraction technique, which mechanically breaks grape skins into small fragments but maintains seed integrity. This study was the first to elucidate the effect of ACE on Shiraz wine's basic chemical composition, colour, phenolic compounds, polysaccharides and sensory profiles. A further aim was to investigate any potential influence provided by ACE on the pre-fermentation water addition to must. ACE did not visually affect Shiraz wine colour, but significantly enhanced the concentration of tannin and total phenolics. Wine polysaccharide concentration was mainly increased in response to the maceration time rather than the ACE technique. ACE appeared to increase the earthy/dusty flavour, possibly due to the different precursors released by the greater skin breakage. The pre-fermentation addition of the water diluted the wine aromas, flavours and astringency profiles. However, combining the ACE technique with water addition enhanced the wine textural quality by increasing the intensities of the crucial astringent wine quality sub-qualities, adhesive and graininess. Furthermore, insights into the chemical factors influencing the astringency sensations were provided in this study. This research indicates that wine producers may use ACE with pre-fermentation water dilution to reduce the wine alcohol level but maintain important textural components. © 2020 by the authors.
|
|
| 5. |
- Lu, Fan, et al.
(författare)
-
Long-Term Phosphorus Addition Strongly Weakens the Carbon Sink Function of a Temperate Peatland
- 2023
-
Ingår i: Ecosystems. - : SPRINGER. - 1432-9840 .- 1435-0629. ; 26:1, s. 201-216
-
Tidskriftsartikel (refereegranskat)abstract
- Peatlands are important nutrient-limited, carbon (C)-accumulating ecosystems where phosphorus (P) is one major limiting nutrient. An increase in P input to peatlands has been observed close to agricultural areas. However, the effects of P input on gross primary productivity (GPP), ecosystem respiration (ER) and net ecosystem exchange (NEE) of peatlands, especially in temperate Asia, have been rarely studied. We selected the P addition plots of a 12-year experiment simulating environmental change in a peatland in northeastern China to evaluate the effect of P addition (5 and 10 kg ha(-1) y(-1)) on carbon dioxide fluxes. Our results showed that the growth of Sphagnum was inhibited but that of vascular plants was facilitated by P addition, resulting in an unchanged GPP. P addition increased ER due to the increased activity potentials of N-acetyl-beta-glucosaminidase (NAG) and polyphenol oxidase (POX) that might, in turn, increase the metabolic rate of soil microbes and enhance the decomposition of peat. During the growing season, a mean net CO2 absorption of 0.002 mg m(-2) s(-1) was observed at high levels of P addition, which was much lower than that of 0.063 mg m(-2) s(-1) in the controls. The results suggest that long-term P addition will greatly weaken the C sequestration in peatlands by enhancing ER rather than reducing GPP. Our study highlights the importance of the response of vegetation and soil enzyme activities to P addition regarding peatland respiration and C sink function.
|
|
| 6. |
- Suparmaniam, Uganeeswary, et al.
(författare)
-
Enhancing high-density microalgae cultivation via exogenous supplementation of biostimulant derived from onion peel waste for sustainable biodiesel production
- 2024
-
Ingår i: Journal of Environmental Management. - : Elsevier. - 0301-4797 .- 1095-8630. ; 359
-
Tidskriftsartikel (refereegranskat)abstract
- Microalgae demonstrate significant potential as a source of liquid-based biofuels. However, increasing biomass productivity in existing cultivation systems is a critical prerequisite for their successful integration into large-scale operations. Thus, the current work aimed to accelerate the growth of C. vulgaris via exogenous supplementation of biostimulant derived from onion peel waste. Under the optimal growth conditions, which entailed a biostimulant dosage of 37.5% v/v, a pH of 3, an air flow rate of 0.4 L/min, and a 2% v/v inoculum harvested during the mid-log phase, yielded a maximum biomass concentration of 1.865 g/L. Under the arbitrarily optimized parameters, a comparable growth pattern was evident in the upscaled cultivation of C. vulgaris, underscoring the potential commercial viability of the biostimulant. The biostimulant, characterized through gas chromatography-mass spectrometry (GC-MS) analysis, revealed a composition rich in polyphenolic and organo-sulphur compounds, notably including allyl trisulfide (28.13%), methyl allyl trisulfide (23.04%), and allyl disulfide (20.78%), showcasing potent antioxidant properties. Additionally, microalgae treated with the biostimulant consistently retained their lipid content at 18.44% without any significant reduction. Furthermore, a significant rise in saturated fatty acid (SFA) content was observed, with C16:0 and C18:1 dominating both bench-scale (44.08% and 14.01%) and upscaled (51.12% and 13.07%) microalgae cultures, in contrast to the control group where C18:2 was prevalent. Consequently, SFA contents reached 54.35% and 65.43% in bench-scale and upscaled samples respectively, compared to 33.73% in the control culture. These compositional characteristics align well with the requirements for producing high-quality crude biodiesel.
|
|
| 7. |
- Wang, Jinpeng, et al.
(författare)
-
Metabolic engineering for increased lipid accumulation in Yarrowia lipolytica – A Review
- 2020
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 313
-
Forskningsöversikt (refereegranskat)abstract
- Current energy security and climate change policies encourage the development and utilization of bioenergy. Oleaginous yeasts provide a particularly attractive platform for the sustainable production of biofuels and industrial chemicals due to their ability to accumulate high amounts of lipids. In particular, microbial lipids in the form of triacylglycerides (TAGs) produced from renewable feedstocks have attracted considerable attention because they can be directly used in the production of biodiesel and oleochemicals analogous to petrochemicals. As an oleaginous yeast that is generally regarded as safe, Yarrowia lipolytica has been extensively studied, with large amounts of data on its lipid metabolism, genetic tools, and genome sequencing and annotation. In this review, we highlight the newest strategies for increasing lipid accumulation using metabolic engineering and summarize the research advances on the overaccumulation of lipids in Y. lipolytica. Finally, perspectives for future engineering approaches are proposed.
|
|
| 8. |
- Wang, Shuang, et al.
(författare)
-
Microbial formation and stabilisation of soil organic carbon is regulated by carbon substrate identity and mineral composition
- 2022
-
Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 414
-
Tidskriftsartikel (refereegranskat)abstract
- The view that soil organic C (SOC) is formed mainly from non-metabolised and recalcitrant organic residues is being challenged by an emerging view that metabolic by-products form more stable associations with soil minerals. However, the effects of C substrate identity and soil mineral composition (and interactions) on microbial physiology and SOC formation are still not well understood. We added contrasting substrates (glucose, alanine and a mixture of glucose, alanine, and oxalic acid) into artificial soils of varying mineral composition (montmorillonite, kaolinite, and kaolinite plus goethite and hematite) for 12 weeks. We found that glucose led to 1.45 and 1.75 times more SOC formation than alanine and the mixed substrate, respectively. Montmorillonite based soils gained approximately 1.3 times more SOC compared to the other two soils. Compared with kaolinite-only soils, the inclusion of goethite and hematite had a positive effect on total SOC, extracellular C and biologically stable C when amended with alanine, but a negative effect on these SOC fractions when amended with glucose. Soils with greater SOC formation were associated with high microbial C use efficiency (CUE) and extracellular C, suggesting that spatial allocation by the microbial biomass is pivotal for creating stable SOC. Fungi-dominated soils typically had a higher CUE, which was positively correlated with the formation of new SOC. These results suggest that the identity of plant inputs will have a strong bearing on the formation of SOC via interactions with the soil microbial community and soil mineralogy.
|
|
| 9. |
- Wang, Zhenxing, et al.
(författare)
-
Polymerase IV Plays a Crucial Role in Pollen Development in Capsella
- 2020
-
Ingår i: Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 32, s. 950-966
-
Tidskriftsartikel (refereegranskat)abstract
- Unlike in Arabidopsis, loss of function of Polymerase IV in the Brassicaceae species Capsella rubella causes microspore arrest, revealing an important role for Polymerase IV in pollen development.In Arabidopsis (Arabidopsis thaliana), DNA-dependent RNA polymerase IV (Pol IV) is required for the formation of transposable element (TE)-derived small RNA transcripts. These transcripts are processed by DICER-LIKE3 into 24-nucleotide small interfering RNAs (siRNAs) that guide RNA-directed DNA methylation. In the pollen grain, Pol IV is also required for the accumulation of 21/22-nucleotide epigenetically activated siRNAs, which likely silence TEs via post-transcriptional mechanisms. Despite this proposed role of Pol IV, its loss of function in Arabidopsis does not cause a discernible pollen defect. Here, we show that the knockout of NRPD1, encoding the largest subunit of Pol IV, in the Brassicaceae species Capsella (Capsella rubella), caused postmeiotic arrest of pollen development at the microspore stage. As in Arabidopsis, all TE-derived siRNAs were depleted in Capsella nrpd1 microspores. In the wild-type background, the same TEs produced 21/22-nucleotide and 24-nucleotide siRNAs; these processes required Pol IV activity. Arrest of Capsella nrpd1 microspores was accompanied by the deregulation of genes targeted by Pol IV-dependent siRNAs. TEs were much closer to genes in Capsella compared with Arabidopsis, perhaps explaining the essential role of Pol IV in pollen development in Capsella. Our discovery that Pol IV is functionally required in Capsella microspores emphasizes the relevance of investigating different plant models.
|
|
| 10. |
- Zhu, Youjian, et al.
(författare)
-
Fluidized bed co-gasification of algae and wood pellets : gas yields and bed agglomeration analysis
- 2016
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 30:3, s. 1800-1809
-
Tidskriftsartikel (refereegranskat)abstract
- Algae utilization in energy production has gained increasing attention as a result of its characteristics, such as high productivity, rapid growth rate, and flexible cultivation environment. In this paper, three species of algae, including a fresh water macroalgae, Oedogonium sp., a saltwater macroalgae, Derbersia tenuissima, and a microalgae species, Scenedesmus sp., were studied to explore the potential of using smaller amounts of algae fuels in blends with traditional woody biomasses in the gasification processes. Co-gasification of 10 wt % algae and 90 wt % Swedish wood pellets was performed in a fluidized bed reactor. The effects of algae addition on the syngas yield and carbon conversion rate were investigated. The addition of 10 wt % algae in wood increased the CO, H2, and CH4 yields by 3–20, 6–31, and 9–20%, respectively. At the same time, it decreased the CO2 yield by 3–18%. The carbon conversion rates were slightly increased with the addition of 10 wt % macroalgae in wood, but the microalgae addition resulted in a decrease of the carbon conversion rate by 8%. Meanwhile, the collected fly ash and bed material samples were analyzed using scanning electron microscopy combined with an energy-dispersive X-ray detector (SEM–EDX) and X-ray diffraction (XRD) technique. The fly ashes of wood/marcoalgae tests showed a higher Na content with lower Si and Ca contents compared to the wood test. The gasification tests were scheduled to last 4 h; however, only wood and wood/Derbersia gasification experiments were carried out without significant operational problems. The gasification of 10 wt % Oedogonium N+ and Oedogonium N– led to defluidization of the bed in less than 1 h, and the wood/Scenedesmus (WD/SA) test was stopped after 1.8 h as a result of severe agglomeration. It was found that the algae addition had a remarkable influence on the characteristics and compositions of the coating layer. The coating layer formation and bed agglomeration mechanism of wood/macroalgae was initiated by the reaction of alkali compounds with the bed particles to form low-temperature melting silicates (inner layer). For the WD/SA test, the agglomeration was influenced by both the composition of the original algae fuel as well as the external mineral contaminations. In summary, the operational problems experienced during the co-gasification tests of different algae–wood mixtures were assigned to the specific ash compositions of the different fuel mixtures. This showed the need for countermeasures, specifically to balance the high alkali content, to reach stable operation in a fluidized bed gasifier.
|
|
