Vacuum Infiltration Treatment Research Articles

Experimental Study on Strength Enhancement and Porosity Variation of 3D-Printed Gypsum Rocks: Insights on Vacuum Infiltration Post-Processing

Three-dimensional printing (3DP) technology has shown great potential in rock mechanics and mining engineering due to its ability to create complex and customized objects with high precision and accuracy. At present, an emerging research focus is improving the mechanical properties of 3D-printed samples, which originally has low strength and stiffness, to match those of natural rocks. The objective of this study was to investigate the effectiveness of different post-treatments on the strength enhancement of 3D-printed gypsum samples. To achieve this goal, 3D-printed gypsum samples were subjected to different post-treatments including dipped infiltration treatment and vacuum infiltration treatment using different infiltrants: water, saltwater, ColorBond, and StrengthMax. Subsequently, each sample was subjected to ultrasonic wave velocity testing and uniaxial compression experiments to characterize their mechanical properties, CT scans to investigate their microstructural characteristics. Additionally, X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) tests were conducted to explore the underlying reasons for changes in macroscopic strength. Finally, the physical characteristics and mechanical properties of untreated and post-processed 3D-printed gypsum samples were compared with natural rocks. The results showed that the strength of samples treated with water and saltwater was much lower than that of those treated with ColorBond and StrengthMax, while the porosity was the opposite. In water-treated and saltwater-treated samples, water or saltwater treatment can alter particle characteristics, but weak adhesive bonding and numerous pores result in low mechanical strength. Samples treated with Colorbond or StrengthMax exhibit improved strength due to effective gap filling and cohesive structure formation, with StrengthMax-treated samples showing higher strength despite having more pores than Colorbond-treated ones. Moreover, the physical and mechanical properties of these treated samples matched a wider range of natural rock types compared to the untreated samples.

Improved Agrobacterium-mediated transformation of cowpea via sonication and vacuum infiltration

An improved method of Agrobacterium-mediated transformation of cowpea was developed employing both sonication and vacuum infiltration treatments. 4 day-old cotyledonary nodes were used as explants for co-cultivation with Agrobacterium tumefaciens strain EHA105 harbouring the binary vector pSouv-cry1Ac. Among the different injury treatments, vacuum infiltration and their combination treatments tested, sonication for 20 s followed by vacuum infiltration for 5 min with A. tumefaciens resulted in highest transient GUS expression efficiency (93% explants expressing GUS at regenerating sites). After 3 days of co-cultivation, the explants were cultured in 150 mg/l kanamycin-containing selection medium and putative transformed plants were recovered. The presence, integration and expression of nptII and cry1Ac genes in T0 transgenic plants were confirmed by polymerase chain reaction (PCR), genomic Southern and qualitative reverse transcription (RT)-PCR analysis. Western blot hybridization and enzyme-linked immunosorbent assay (ELISA) detected and demonstrated the accumulation of Cry1Ac protein in transgenic plants. The cry1Ac gene transmitted in a Mendelian fashion. The stable transformation efficiency increased by 88.4% using both sonication-assisted Agrobacterium-mediated transformation (SAAT) and vacuum infiltration than simple Agrobacterium-mediated transformation in cowpea.

Physiological and quality responses of Chinese ‘Suli’ pear (Pyrus bretschneideri Rehd) to 1‐MCP vacuum infiltration treatment

1-Methylcyclopropene (1-MCP) is a potent inhibitor of ethylene action and can maintain the quality and extend the shelf life of fresh produce. But the effectiveness of application of 1-MCP may depend upon its capacity to diffuse into the flesh tissue. However, to our knowledge, no study has been performed on the quality maintenance of pear fruit treated with 1-MCP vacuum infiltration. The objectives of this study were to examine the effect of 1-MCP vacuum-infiltration treatment on post-harvest quality and physiology of 'Suli' pears (Pyrus bretschneideri Rehd). 1-MCP treatment led to decreased losses in flesh firmness and titratable acidity (TA), delayed change in skin colour and reduced polyphenol oxidase (PPO) activity and accumulation of malondialdehyde (MDA) during cold storage. It also inhibited flesh browning and maintained a higher taste score after shelf life. These effects were higher when fruits were vacuum-infiltrated with 1-MCP. However, 1-MCP had little effect on total soluble solids (TSSs) and respiration rate of pear. Overall, our results indicated that 1-MCP vacuum infiltration treatment was effective in controlling fruit ripening changes.

Agrobacterium tumefaciens-mediated genetic transformation of a recalcitrant grain legume, lentil (Lens culinaris Medik)

A simple and reproducible Agrobacterium-mediated transformation protocol for a recalcitrant legume plant, lentil (Lens culinaris M.) is reported. Application of wounding treatments and efficiencies of three Agrobacterium tumefaciens strains, EHA105, C58C1, and KYRT1 were compared for T-DNA delivery into lentil cotyledonary node tissues. KYRT1 was found to be on average 2.8-fold more efficient than both EHA105 and C58C1 for producing transient beta-glucuronidase (GUS) gene (gus) expression on cotyledonary petioles. Wounding of the explants, use of an optimized transformation protocol with the application of acetosyringone and vacuum infiltration treatments in addition to the application of a gradually intensifying selection regime played significant roles in enhancing transformation frequency. Lentil explants were transformed by inoculation with Agrobacterium tumefaciens strain, KYRT1 harboring a binary vector pTJK136 that carried neomycin phosphotransferase gene (npt-II) and an intron containing gusA gene on its T-DNA region. GUS-positive shoots were micrografted on lentil rootstocks. Transgenic lentil plants were produced with an overall transformation frequency of 2.3%. The presence of the transgene in the lentil genome was confirmed by GUS assay, PCR, RT-PCR and Southern hybridization. The transgenic shoots grafted on rootstocks were successfully transferred to soil and grown to maturity in the greenhouse. GUS activity was detected in vegetative and reproductive organs of T(0), T(1), T(2) and T(3) plants. PCR assays of T(1), T(2) and T(3) progenies confirmed the stable transmission of the transgene to the next generations.

High-efficiency Agrobacterium-mediated transformation of citrus via sonication and vacuum infiltration

An improved method for the Agrobacterium infiltration of epicotyl segments of 'Pineapple' sweet orange [Citrus sinensis (L.) Osbeck] and 'Swingle' citrumelo [Citrus paradisi Macf. X Poncirus trifoliata (L.) Raf.] was developed in order to increase transformation frequency. Sonication-assisted Agrobacterium-mediated transformation (SAAT), vacuum infiltration, and a combination of the two procedures were compared with conventional Agrobacterium-mediated inoculation method ('dipping' method). It was observed that the morphogenic potential of the epicotyl segments decreased as the duration of SAAT and vacuum treatments increased. Transient GUS expression was not affected by the different SAAT treatments, but it was significantly enhanced by the vacuum infiltration treatments. The highest transformation efficiencies were obtained when the explants were subjected to a combination of SAAT for 2 s followed by 10 min of vacuum infiltration. PCR and Southern blot analysis of the uidA gene were used to confirm the integration of the transgenes. The transformation frequencies achieved in this study (8.4% for 'Pineapple' sweet orange and 11.2% for 'Swingle' citrumelo) are the highest ones reported for both cultivars.

Enhancing the post-harvest qualities of mango fruit by vacuum infiltration treatment with 1-methylcyclopropene

SummaryTo improve the efficacy of 1-methylcyclopropene (1-MCP) treatment of mango fruit, mature green mango fruit (Mangifera indica L. cv. ‘Guifei’) were treated with 0.1, 1.0 or 5.0 µl l–1 1-MCP for 6 h, or with 1.0 µl l–1 1-MCP for 1, 6 or 12 h under vacuum (–80 kPa). Fruit firmness was retained by vacuum treatment with 1-MCP. Levels of 1-MCP as low as 0.1 µl l–1 effectively prevented fruit softening. The shelf-life of mangoes treated with 5.0 µl l–1 1-MCP for 6 h could be extended from 8 d to 12 d after treatment. The duration of vacuum treatment of fruit with 1.0 µl l–1 1-MCP could be as short as 1 h, to prevent softening effectively. Increases in total soluble solids contents and the degradation of protopectin were significantly delayed by treating fruit with 1.0 µl l–1 1-MCP under vacuum for 6 h. Chlorophyll degradation in the peel was inhibited by 1-MCP-treatment. Titratable acidity and the ascorbic acid content of fruit did not change significantly after 1-MCP-treatment. The eating quality of 1-MCP-treated fruit, stored for 12 d, was almost the same as that of control fruit stored for 8 d.

Agrobacterium-mediated transformation of Pisum sativum in vitro and in vivo

Six pea (Pisum sativum L.) cultivars (Adept, Komet, Lantra, Olivin, Oskar, Tyrkys) were transformed via Agrobacterium tumefaciens strain EHA105 with pBIN19 plasmid carrying reporter uidA (β-glucuronidase, GUS, containing potato ST-LS1 intron) gene under the CaMV 35S promoter, and selectable marker gene nptII (neomycin phosphotransferase II) under the nos promoter. Two regeneration systems were used: continual shoot proliferation from axillary buds of cotyledonary node in vitro, and in vivo plant regeneration from imbibed germinating seed with removed testa and one cotyledon. The penetration of Agrobacterium into explants during co-cultivation was supported by sonication or vacuum infiltration treatment. The selection of putative transformants in both regeneration systems carried out on media with 100 mg dm-3 kanamycin. The presence of introduced genes was verified histochemically (GUS assay) and by means of PCR and Southern blot analysis in T0 putative transformants and their seed progenies (T1 to T3 generations). Both methods, but largely in vivo approach showed to be genotype independent, resulting in efficient and reliable transformation system for pea. The in vivo approach has in addition also benefit of time and money saving, since transgenic plants are obtained in much shorter time. All tested T0 - T3 plants were morphologically normal and fertile.

Pre-Culture Treatment Enhances Transient GUS Gene Expression in Leaf Segment of Saintpaulia ionantha Wendl. after Inoculation with Agrobacterium tumefaciens.

We studied the effects of various treatments given before or at inoculation with Agrobacterium tumefaciens strain EHA105 (pIG121Hm) on the transient GUS gene expression in leaf segments of Saintpaulia ionantha Wendl. Sonication and vacuum infiltration treatments in the presence of Agrobacterium had no positive effect on GUS expression. In contrast, the explants cultured for 3 to 5 weeks on shoot induction medium containing 0.5mgl-1 NAA and 0.5mgl-1 BA, prior to Agrobacterium inoculation markedly increased transient GUS expression. The addition of acetosyringone to the co-cultivation medium enhanced the GUS expression. A similar enhancing effect was observed in all of the 4 cultivars examined, suggesting the wide applicability of the pre-culture treatment.

The response of partly cooled tulips to vacuum infiltration with gibberellins

Partly cooled (5°C) tulip ‘Apeldoorn’ were treated with gibberellins GA 3 and GA 4 + 7 by vacuùm infiltration, with a view to defining conditions suitable for exploiting the effects of GA on forced tulips (faster flowering, control of stem extension, reduction of floral bud blasting). The first experiment showed that GA 3 and GA 4 + 7 were equally effective in reducing the glasshouse period following 6 or more weeks cold storage; with less than 6 weeks cold storage, effects were less marked. Stem length at flowering was reduced by GA treatments, particularly by GA 3 and following more than 6 weeks cold storage. However, the vacuum infiltration method used (30 min at 10 torr) resulted in serious flower losses. Next, the effect of GA 3 concentration (up to 1500 mg 1 −1) was studied using vacuum infiltration treatments for 1–15 min at 20–510 torr, which resulted in fewer flower losses. Following 4 weeks cold storage, reducing pressure or increasing GA 3 concentration reduced both glasshouse period and stem length, with no effect of duration of treatment; GA 3 concentration was the only factor affecting flower length, which was increased. Following 8 weeks cold storage, increasing GA 3 concentration, vacuum or duration reduced glasshouse period. With all 3 factors at their maximum levels, 16 days earliness was obtained compared with controls. With maximum earliness, stem length was reduced to about 23 cm, compared to about 26 cm for treatments giving about 1 week's earliness, and 32 cm for untreated controls. Increasing vacuum appeared the most economical way of obtaining earliness, 20 torr giving 7 days earliness even at only 250 mg GA 3 1 −1. Treatments giving earlier flowering also gave larger flowers. For comparison, there was little effect of soaking bulbs at atmospheric pressure even at 500 mg GA 3 1 −1 for up to 20 h. Further experiments, conducted with vacuum infiltration at 260 torr for 15 min, confirmed these GA effects using formulated GA 3 (as “Berelex”) and GA 4 + 7 (as “Regulex”). Effects of GA on stem length at flowering had disappeared by the time stems reached their final length. Comparisons with bulb injection of GA showed that this method required less GA than vacuum infiltration for similar effects, and that the greater effectiveness of GA 4 + 7 compared with GA 3 was less marked using vacuum infiltration.

Factors Influencing CO2-induced Peel Injury of ‘Golden Delicious’ Apples1

Abstract Dipping or vacuum infiltrating ‘Golden Delicious’ apples (Malus domestica Borkh.) with water before a 10-day 17% CO2 gassing treatment increased the incidence and severity of CO2-associated peel injury. Susceptible fruits receiving a localized water treatment using flannelette rings were injured preferentially in the wet areas. When the flannelette rings were soaked with water, carbonic acid, 0.05 m succinate, 0.05 m oxalacetate and 0.05 m malonate and the fruits held in controlled atmosphere storage, only malonate caused severe surface injury. Dips or vacuum infiltration treatments involving malonate caused a similar type of injury. However, this injury was clearly different in appearance from CO2 injury. Infiltrating fruits with 0.02 n HCl (pH 1.8) caused no injury suggesting that CO2 injury is not simply due to tissue acidification.

STUDIES OF CAVITATION IN ISOLATED VASCULAR BUNDLES AND WHOLE LEAVES OF PLANTAGO MAJOR L.

SummaryCavitation has been studied by acoustic detection in preserved and fresh vascular bundles and in whole leaves of Plantago and other plants. ‘Clicks’, indicating cavitation vibrations, were produced as vascular bundles lost water in a manner similar to that of Ricinus leaves (Milburn, 1973a), but the process was more rapid and freely suspended bundles jerked as they cavitated, like spore elator systems. Clicks were counted in a semi‐quantitative study of both cavitation and the reverse process, the restoration of water‐filled xylem conduits. Restoration was greatly enhanced by compression or vacuum infiltration treatments in comparison with simple soaking: apparently gas entrainment is the major obstacle preventing refilling.Cavitation within wilting leaves was much less extensive than when isolated bundles are dried, indicating that cavitation is generally incomplete under natural conditions. Xylem sap tensions at which cavitation is incipient were estimated approximately by balancing cavitation against the external humidity. Sap tensions at incipient cavitation could be measured more accurately using a pressure bomb, however. These tensions were surprisingly low, covering a range of tensions (5‐15 bar) expected to occur under field conditions. Cavitation was detected in Plantago under natural field conditions and in other plants also, especially Tussilago, Further implications are discussed.