Search

Background: Tractography based on diffusion MRI (dMRI) is a useful tool to study white matter of the developing brain. However, its application in fetal brains is limited due to motion artifacts and low resolution of in utero dMRI, leading to reduced reliability, which was scarcely investigated in previous studies. Purpose: To identify reliably traceable fibers in fetal brains and assess whether reproducibility varies with gestational age (GA) and varies between brain regions. Study Type: Prospective cohort study. Subjects: A total of 44 healthy fetuses with GAs between 25 and 37 (31 ± 6). Field Strength/Sequence: 3‐T, diffusion‐weighted echo‐planar imaging sequence (2–5 repeated dMRI scans within the same session per subject). Assessment: We fitted dMRI with constrained spherical deconvolution model and conducted tractography on eight fibers. We extracted volume, fractional anisotropy, and fiber count for each fiber and assessed the reproducibility of these metrics between repeated scans within each subject. Data were divided into two age‐based subgroups (≤30 weeks, N = 28, and >30 weeks, N = 16) for further tests. Statistical Tests: The reproducibility were compared between fibers by analysis of variance and two‐sample t tests. Multiple comparisons were corrected by the false discovery rate (5% was accepted). Results: The reproducibility of the anterior thalamic radiation, inferior longitudinal fasciculus (ILF), genu of the corpus callosum (GCC), and body of the corpus callosum (BCC) significantly decreased with advancing GA (correlation coefficient = 0.525–0.823), as confirmed by group comparisons between fetuses in early GA (≤30 weeks) and late GA (>30 weeks) groups. Corticospinal tract, inferior fronto‐occipital fasciculus, and GCC showed high reproducibility for fiber count (weighted dice average = 0.846 vs. 0.814), while BCC and ILF exhibited the lowest reproducibility in both age groups. Data Conclusion: The study indicates that the reliability of fetal brain tractography depends on GA and varies among different fibers. Level of Evidence: 2 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Blueberries are rich in a variety of functional substances and have high nutritional and health values, but they are not resistant to decline during fresh storage. Here, the effects of six Bacillus species on the storage quality of, and antioxidant levels in, the southern highbush blueberry 'O'Neal' fruit were investigated. Bacillus treatments reduced the fruit decay rate, slowed fruit quality decline, inhibited malondialdehyde accumulation, and increased superoxide dismutase and peroxidase activity levels. Bacillus altitudinis Y-14 had the best effect overall. Furthermore, the effects of 1-methylcyclopropene (1-MCP), B. altitudinis Y-14, and 1-MCP + B. altitudinis Y-14 treatments on the storage quality and antioxidant of rabbiteye blueberry 'Brightwell' fruit were investigated, and each treatment effectively reduced the decay rate and weight loss of fruit. When stored for 25 days, the decay rate of the 1-MCP + B. altitudinis Y-14 group was only 8.33%, significantly lower than that of the control. The three treatments delayed the decline in fruit quality, inhibited malondialdehyde accumulation, and increased superoxide dismutase and peroxidase activity levels. The 1-MCP + B. altitudinis Y-14 treatment was more conducive to prolonging the postharvest storage period of blueberries and had the best effect in delaying the decline in fruit quality. Thus, combined 1-MCP and B. altitudinis Y-14 treatment may be an effective way to improve the storage quality and extend the storage period of blueberries, which provides a new way for storing and transporting blueberries to reduce costs and improve economic benefits. [ABSTRACT FROM AUTHOR]

Background: Auxin, a plant hormone, plays diverse roles in the modulation of plant growth and development. The transport and signal transduction of auxin are regulated by various factors involved in shaping plant morphology and responding to external environmental conditions. The auxin signal transduction is primarily governed by the following two gene families: the auxin response factor (ARF) and auxin/indole-3-acetic acid (AUX/IAA). However, a comprehensive genomic analysis involving the expression profiles, structures, and functional features of the ARF and AUX/IAA gene families in Vaccinium bracteatum has not been carried out to date. Results: Through the acquisition of genomic and expression data, coupled with an analysis using online tools, two gene family members were identified. This groundwork provides a distinguishing characterization of the chosen gene families in terms of expression, interaction, and response in the growth and development of plant fruits. In our genome-wide search of the VaARF and VaIAA genes in Vaccinium bracteatum, we identified 26 VaARF and 17 VaIAA genes. We analyzed the sequence and structural characteristics of these VaARF and VaIAA genes. We found that 26 VaARF and 17 VaIAA genes were divided into six subfamilies. Based on protein interaction predictions, VaIAA1 and VaIAA20 were designated core members of VaIAA gene families. Moreover, an analysis of expression patterns showed that 14 ARF genes and 12 IAA genes exhibited significantly varied expressions during fruit development. Conclusion: Two key genes, namely, VaIAA1 and VaIAA20, belonging to a gene family, play a potentially crucial role in fruit development through 26 VaARF-IAAs. This study provides a valuable reference for investigating the molecular mechanism of fruit development and lays the foundation for further research on Vaccinium bracteatum. [ABSTRACT FROM AUTHOR]

To further clarify the impact of different rootstocks in grafted blueberry, fruit quality, mineral contents, and leaf gas exchange were investigated in 'O'Neal' blueberry (Vaccinium corymbosum) grafted onto 'Anna' (V. corymbosum) (AO), 'Sharpblue' (V. corymbosum) (SO), 'Baldwin' (V. virgatum) (BO), 'Plolific' (V. virgatum) (PO), and 'Tifblue' (V. virgatum) (TO) rootstocks and own-rooted 'O'Neal' (NO), and differences in anatomic structures and drought resistance were determined in AO, TO, and NO. The findings revealed that fruit quality in TO and PO was excellent, that of BO and SO was good, and that of AO and NO was medium. 'Tifblue' and 'Plolific' rootstocks significantly increased the levels of leaf phosphorus and net photosynthetic rate of 'O'Neal', accompanied by a synchronous increase in their transpiration rates, stomatal conductance, and intercellular CO2. Additionally, the comprehensive evaluation scores from a principal component analysis based on anatomic structure traits from high to low were in the order TO > AO > NO. The P50 (xylem water potential at 50% loss of hydraulic conductivity) values of these grafted plants descended in the order NO > AO > TO, and the branch hydraulic conductivity of TO and sapwood hydraulic conductivity of TO and AO were significantly lower than those of NO. Thus, TO plants exhibited the strongest drought resistance, followed by AO, and NO, and this trait was related to the effects of different rootstocks on the fruit quality of 'O'Neal' blueberry. These results provided a basis for a deeper understanding of the interaction between rootstocks and scions, as well mechanisms to improve blueberry fruit quality. [ABSTRACT FROM AUTHOR]

The dynamical behavior of Richtmyer-Meshkov instability-induced turbulent mixing under multiple shock interactions is investigated by large-eddy simulation. After the initial shockwave-interface interaction, the transmitted wave reverberates between the accelerated interface and the end-wall of the shock tube to form a process of multiple shock interactions. The turbulent mixing zone grows in a different manner under each of the impingements. After the initial shock, it grows as a power law of time. After the reshock and the impingement of the reflected rarefaction wave, it grows with time as a different negative exponential law. When the impingement of the reflected compression wave completes, it grows approximately in a linear fashion. The statistical quantities in the turbulent mixing zone evolve with time in a similar way under multiple impingements, and after the impingement of the reflected compression wave, they all decay asymptotically. Therefore, the turbulent mixing zone behaves in a statistically self-similar pattern. Even though the impingements of different waves result in different abrupt changes of the characteristic scale parameters of mixing turbulence, as a whole, the characteristic scales present a feature of growth, and the characteristic-scale Reynolds numbers present a feature of decay. The mixing flow is continuously anisotropic, yet the anisotropy weakens gradually. Therefore the development of turbulent mixing presents a trend of isotropy. Key words: Richtmyer-Meshkov instability, turbulent mixing, multiple shock, large-eddy simulation, statistical self-similarity. Dans une simulation de grands tourbillons, nous etudions le comportement dynamique du melange turbulent de Richtmyers-Meshkov induit par instabilites sous des chocs multiples. Apres l'interaction initiale entre l'onde de choc et l'interface, l'onde transmise reverbere entre l'interface acceleree et le mur du fond du tube de choc, pour generer un mecanisme a chocs multiples. La zone de melange croit de facon differente sous chaque impact. Apres le premier choc, elle croit comme une loi de puissance du temps. Apres le retour et l'impact de l'onde de rarefaction, elle croit dans le temps avec une loi exponentielle negative differente. Lorsque l'impact de l'onde de compression reflechie complete son mouvement, la zone a une croissance approximativement lineaire avec le temps. Les quantites statistiques dans la zone de melange turbulent evoluent dans le temps de facon similaire et apres l'impact de l'onde de compression reflechie, elles decroissent asymptotiquement. Par consequent, la zone de turbulence se comporte statistiquement selon un patron d'autosimilarite. Meme si les impacts des differentes ondes generent des variations differentes abruptes des parametres d'echelle caracteristique de la turbulence, dans leur ensemble, les echelles caracteristiques presentent une croissance, alors que l'echelle caracteristique du nombre de Reynolds presente une decroissance. Le flot de melange est continuellement anisotrope, mais l'anisotropie diminue graduellement. Par consequent, le developpement de la zone de melange turbulent tend vers l'isotropie. [Traduit par la Redaction] Mots-cles: instabilite de Richtmyers-Meshkov, melange turbulent, chocs multiples, simulation de grands tourbillons, autosimilarite statistique., 1. Introduction As a shock wave passes through a perturbed interface between two different fluids, the baroclinic vorticity is deposited at the interface due to the misalignment of the pressure [...]