Low-pressure Treatment Research Articles

Bonding of Graphene to ZnO by Low-Temperature and Low-Pressure Treatment and Their Photocatalytic Properties

Bonding of Graphene to ZnO by Low-Temperature and Low-Pressure Treatment and Their Photocatalytic Properties

Düşük Basınç Uygulaması Taze ve Depolanmış Sudak Balığının (Sander lucioperca) Fizikokimyasal ve Mikrobiyolojik Özelliklerini Geliştirdi

IIn this study, low-pressure treatment was applied to pike-perch and the changes in quality criteria during the storage process were examined. L*, a*, and b* values in samples treated with low pressure were significantly different compared to the control. It was observed that the process had an improving effect on the textural properties of the fish. While the aw value decreased to 0.822, the pH value decreased to 6.47. While TBARS values of the samples ranged between 0.014 and 0.031 mg MA / kg, TVB-N values ranged between 7.69 and 24.06 mg / 100 g. Total aerobic mesophilic bacteria, yeast/mold, total coliform group bacteria, and total aerobic psychrophilic bacteria counts of all samples exposed to low-pressure treatment were lower than the control during storage. As a result, the treatment positively affected the quality of pikeperch meat during the storage period.

CO2-diffusion controlled mesophase formation in poly(l-lactic acid) and its effect on cold-crystallization

A mild CO2-treatment of a poly(l-lactic acid) PLLA disk with tailored geometry allowed to compare cold crystallization of PLLA containing α"-mesophase, with cold-crystallization of fully amorphous PLLA, both coexisting within a single sample. The use of PLLA disks with 0.5 mm thickness, low CO2 pressure (3.0 MPa) and short treatment time (5 min) at 25 °C, led to only partial diffusion of the gas into the polymer. CO2-induced mesophase developed in surface-near regions of the disks, where CO2 penetrated, whereas the core of the samples was not reached by the gas and remained amorphous. Cold-crystallization of CO2-treated PLLA was analyzed after full desorption of the gas, using different heating rates. Slow heating allowed to identify two cold-crystallization events: low-temperature cold-crystallization in the outer parts of the sample treated with CO2, promoted by prior formation of the α"-mesophase, and high-temperature cold-crystallization, occurring at similar temperatures as in case of non-CO2-treated amorphous PLLA. In both cases, cold-crystallization led to formation of conformationally disordered α′-crystals, as revealed by temperature-resolved wide-angle X-ray scattering. This study confirms that formation of α′-crystals is mainly controlled by the crystallization temperature, also when crystallization is promoted by the prior presence of a mesophase.

Controlling the Intermediate Phase to Improve the Crystallinity and Orientation of Cs3Sb2ClxI9‐x Films for Efficient Solar Cells

AbstractLead‐free 2D antimony‐based halide perovskites with excellent optoelectronic properties, low toxicity, and good intrinsic stability are promising for photovoltaic devices. However, the power conversion efficiency (PCE) of antimony‐based perovskite solar cells (PSCs) is still lower than 3% due to the poor crystallinity and random orientation. Herein, it is found that the Cs3Sb2ClxI9‐x films prepared by adding methylamine chloride as an additive to the precursor solution can form a mixed intermediate phase with 0D dimer phase and 2D layered phase after low pressure treatment. During the annealing process, the 0D dimer phase will completely transition to 2D layered phase due to the partial replacement of I by Cl. Compared to adding SbCl3 directly, this method considerably increases the crystallinity of Cs3Sb2IxCl9‐x films. The obtained films have a preferential orientation along the (201) direction, which is beneficial for charge carrier transportation. Consequently, the champion device shows a PCE of 3.2%, which is one of the highest efficiencies achieved for inorganic Sb‐based PSCs with the n‐i‐p architecture to date.

Tolerance of high mountain quinoa to simulated extraplanetary conditions. Changes in surface mineral concentration, seed viability and early growth

We studied the tolerance of one species of quinoa achenes from ecotype RQ252 to simulated extraplanetary conditions in a vacuum chamber (high low-pressure 10–2 to 10-7 Torr, UV laser simulated plasma radiation, and cryogenic temperature). The selection of this ecotype of quinoa achenes was a condition to previous studies, where RQ252 shows evidence of high efficacy in grow adaptation in the South America Puna between 3800–4500 m asl subjected to low oxygen and increased UV radiation exposition. After extraplanetary experiment exposure, we evaluated quinoa tolerance to experimental conditions through germination and early growth responses under a controlled laboratory standard atmosphere. Rate and final germination subjected to high low-pressure treatments during 4 h, 8 h, and 16 h were not different to control. Laser plasma application accelerated the germination rates. Final germination always reaches values up to 90%. SEM-EDS analysis showed structural changes on the pericarp surface, especially in high low-pressure and high low pressure + plasma treatments. EDS revealed that the quinoa pericarp subjected to different treatments showed changes in mineral content. Potassium ions decreased under high low-pressure and high low pressure + laser plasma irradiation (between 32 and 42%) but increased in a prolonged vacuum (35%) and more when plasma was added (96%). Early growth was affected by the different treatments, being the radicle length the most affected parameter. Our results suggest that quinoa achene ecotype RQ252 viability has excellent tolerance to extraplanetary conditions.

Effect of Low Pressure and Low Oxygen Treatments on Fruit Quality and the In Vivo Growth of Penicillium digitatum and Penicillium italicum in Oranges

Penicillium digitatum and P. italicum are the major postharvest pathogens in citrus. To reduce postharvest decay, the use of low-oxygen (0.9 kPa O2) (LO) or low-pressure (6.6 kPa) (LP) treatments were evaluated during the storage of navel oranges for four or eight days. The results showed that exposure to both LO and LP treatments reduced in vivo pathogen growth compared to the untreated (UTC) oranges, with LO being the most effective. The effects of LO and LP on fruit metabolism and quality were further assessed, and it was found that there was no effect on fruit ethylene production, respiration rate, TSS (total soluble solids), TA (titratable acidity) or fruit firmness. However, both LO and LP treatments did have an effect on juice ethanol concentration and fruit weight-loss. The effect of adding exogenous ethylene at either LP (1 µL/L) or atmospheric pressure (AP) (at either 0.1, 1 µL/L) was also evaluated, and results showed that the addition of ethylene at these concentrations had no effect on mould diameter at LP or AP. Therefore, both LO of 0.9 kPa O2 and LP of 6.6 kPa at 20 °C are potential non-chemical postharvest treatments to reduce mould development during storage with minimal effects on fruit quality.

Preliminary investigations on the effect of low-pressure treatment on in vitro and in vivo growth of Penicillium sp. in oranges

ISHS V International Symposium on Postharvest Pathology: From Consumer to Laboratory-Sustainable Approaches to Managing Postharvest Pathogens Preliminary investigations on the effect of low-pressure treatment on in vitro and in vivo growth of Penicillium sp. in oranges

Using the sun to co-generate electricity and freshwater

Using the sun to co-generate electricity and freshwater

Change in Quality of Pork Belly and Pork Shoulder with Low Temperature Hydrostatic Pressure and Ultrasound Treatment during Storage

Change in Quality of Pork Belly and Pork Shoulder with Low Temperature Hydrostatic Pressure and Ultrasound Treatment during Storage

Influence of Low-Pressure Treatment on the Morphological and Compositional Stability of Microscopic Ettringite.

The impact of low-pressure treatment on the crystal structure, morphology, and chemical composition of ettringite, due to their major importance with respect to processability (i.a., drying conditions) and to the analysis of ettringite-containing samples, is examined utilizing X-ray diffraction, thermogravimetric analysis, Raman spectroscopy, and environmental scanning electron microscopy. Synthetic ettringite was treated for various durations (5 min up to 72 h) and at two different levels of low-pressure (4.0 mbar and 60 µbar). Evaluation showed a correlation between the procedural parameters (time and pressure), the chemical composition, and the morphology of ettringite. The experiments reveal that, when exposed to 4 mbar pressure, nearly no changes occur in the ettringite’s morphology, whereas the crystals undergo swelling and slight deformations at very low pressures (60 µbar and 35.3 nbar), which is attributed to the loss of bound water and the partial transformation from ettringite to quicklime, anhydrite, and calcium aluminate. Furthermore, the strongly dehydrated ettringite shows the same morphology.

Low-pressure treatment of CuSCN hole transport layers for enhanced carbon-based perovskite solar cells

Low-cost and stable carbon-based hole-conductor layers have attained especial interest in perovskite solar cells (PSCs). Because the carbon-based hole-conductor-free PSCs usually have the serious problems of low power conversion efficiency (PCE) and obvious current hysteresis. Herein, we introduced CuSCN hole transfer layers (HTLs) with low pressure treatment (LPT) into carbon-based PSCs to improve the performance and reduce the hysteresis. After being coated, the CuSCN layers were immediately transferred to low-pressure environment for vaporizing the polar diethyl sulfide (DES) without destruction of perovskite films. Our champion device engineered through carbon-based PSCs with low-pressure-treated CuSCN HTLs achieved power conversion efficiency (PCE) of 13.05%, compared with 10.6% of that without CuSCN layer. Importantly, the incorporating CuSCN HTLs can build energy level cascade to obviously reduce the current hysteresis due to the balanced electrode-hole extraction ability. Moreover, the stability of the device was obviously improved due to the hydrophobic nature of CuSCN layer. While the low-temperature (~20 °C and 50 °C) volatilizing DES in CuSCN layer destroyed the perovskite films under room pressure, which reduced the PCE to 8.6% and 9.9%, respectively. Thereby, this work highlights the advantages of incorporating low-pressure-treated CuSCN HTLs into carbon-based PSCs with improving performance and reducing current hysteresis, which will promote the future industrial application.

Effects of low-pressure storage of food commodities on the mortality of adult stored product insects

The food industry faces serious problems regarding pest infestation leading to high storage loss of food commodities. Due to adverse impacts of chemical preservation methods, a promising physical method of food protection could be considered as an urgent need. This study investigated the effect of low-pressure (vacuum) on the mortality of adults of three stored product pests of drug store beetle (Stegobium paniceum L.), southern cowpea weevil (Callosobruchus chinensis L.) and red flour beetle (Tribolium castaneum Herbst). The pests were exposed to 20 kPa and 10 kPa vacuum at 37 ºC and 75% relative humidity. Mortality of the insects was recorded at 8 h and 32 h after vacuum treatments. There were significant differences (p<0.05) in the susceptibility to the vacuum treatment among the tested pests. Adults of C. chinensis showed comparatively less susceptibility to the vacuum treatment compared to S. paniceum and T. castaneum. Mortality of insects exposed to two low-pressure treatments did not show 100% mortality at the two exposure periods, irrespective of the type of food materials and species. The mean percentage mortality increased by about 66.0±5.7% when vacuum pressure increases from 20 kPa to 10 kP irrespective of the species, exposure time and the products. The oxygen concentration decreased to >70% inside the vacuum chamber during treatments.

Sonoreperfusion therapy for microvascular obstruction: A step toward clinical translation

Sonoreperfusion therapy is being developed as an intervention for the treatment of microvascular obstruction. We investigated the reperfusion efficacy of two clinical ultrasound systems (a modified Philips EPIQ and a Philips Sonos 7500) in a rat hindlimb microvascular obstruction model. Four ultrasound conditions were tested using 20 min treatments: Sonos single frame, Sonos multi-frame, EPIQ low pressure and EPIQ high pressure. Contrast-enhanced perfusion imaging of the microvasculature was conducted at baseline and after treatment to calculate microvascular blood volume (MBV). EPIQ high pressure treatment resulted in significant recovery of MBV from microvascular obstruction, returning to baseline levels after treatment. EPIQ low pressure and Sonos multi-frame treatment resulted in significantly improved MBV after treatment but below baseline levels. Sonos single-frame and control groups showed no improvement post-treatment. This study demonstrates that the most effective sonoreperfusion therapy occurs at high acoustic pressure coupled with high acoustic intensity. Moreover, a clinically available ultrasound system is readily capable of delivering these effective therapeutic pulses.

Aspergillus decontamination in hazelnuts: Evaluation of atmospheric and low-pressure plasma technology

Abstract The decontamination effects of non-thermal atmospheric-pressure (AP) and low-pressure (LP) plasma systems were investigated on hazelnuts artificially contaminated with Aspergillus parasiticus and Aspergillus flavus spores. Furthermore, AP-plasma treatment conditions were also optimized. Spore reductions of 5.6 and 4.7 log cfu/g in Aspergillus parasiticus and Aspergillus flavus, respectively, were achieved after 100 W-30 min of LP-air-plasma treatment. Similarly, 5.5 and 5.4 log cfu/g of reductions in Aspergillus parasiticus and Aspergillus flavus, respectively, were achieved after AP-air-plasma treatment at 3000 L/h of gas flow rate, frequency of 25 kHz and reference voltage of 100% (655 W) for 5-cycles (1.7 min). Deformation of spores and loss of spore integrity after plasma treatments were demonstrated with scanning electron microscope (SEM). This study showed that LP and AP plasma treatments might be an alternative method for inactivation of aflatoxin- producing fungi. Industrial relevance Non-thermal (cold) plasma is a promising technology for decontamination of foods due to its safety, ease of use and low temperature processing capability. The results of this study showed that plasma system can be incorporated into a food processing chain, and when initial Aspergillus spp. spores were 7.8–7.9 cfu/g in hazelnut, plasma treatment with reductions of up to 5.6 log cfu/g can compete with other decontamination methods.

Exfoliation of layered yttrium hydroxide by rapid expansion of supercritical suspensions

Rapid expansion of supercritical suspensions was used for the first time to push apart the layers in a layered metal hydroxide structure. Treatment with supercritical CO2 resulted in significant changes in interlayer distances in yttrium hydroxide intercalated with dodecyl sulfate anions. According to XRD, SEM, TEM, nitrogen adsorption and IR-spectroscopy measurements, the structure and composition of the layered material depended substantially on the pressure of supercritical CO2. Low pressure treatment (75–200 atm) resulted in a significant increase (by 20%) in the interlayer distance, while higher pressures did not affect the interlayer distance, but increased the specific surface area of the material (from ∼10 to 74 m2/g). Supercritically treated layered yttrium hydroxide exfoliated readily in toluene under ultrasonication. The re-assembly of exfoliated layers upon solvent evaporation was identified using time-resolved XRD. No effect of supercritical CO2 treatment was observed for layered yttrium hydroxide intercalated with nitrate, oleate and stearate anions.

Effects of Low Pressure Treatment on the Mortality of Different Life Stages of Indianmeal moth (Plodia interpunctella) and the Quality of Dried Chinese Jujube.

Low pressure technology is a potential non-chemical method to control insects in agriculture products. The purpose of this study was to determine the tolerance of different life stages of indianmeal moth (Plodia interpunctella) to low pressure and to validate the mortality of P. interpunctella when infesting Chinese jujube (Zizyphus jujuba Miller) using a low pressure system. Results showed that larvae were the most tolerant life stage of P. interpunctella, with a minimum exposure time of 41.4 h at 1.3 kPa and 25 °C to obtain 100% mortality. Pupae were the most susceptible life stage, with a lethal time of 12 h under the above low pressure conditions. The survival ratio of P. interpunctella in jujube decreased with increasing exposure time and reached 0% when the jujubes with P. interpunctella larvae were exposed to low-pressure treatment for 41.6 h at 1.3 kPa and 25 °C. Although the color, moisture, soluble solid, and vitamin C contents were slightly changed, there was no significant quality difference in these factors between control and treated jujubes. The information provided by this study is useful in developing effective non-chemical low-pressure treatments for disinfesting agricultural products.

Low-pressure sprinkler irrigation in maize: Differences in water distribution above and below the crop canopy

Reducing the working pressure at the sprinkler nozzles is one of the alternatives to reduce energy requirements in solid-set sprinkler irrigation systems. Previous studies reported ≈10% lower seasonal Christiansen uniformity coefficient (CUC) for low-pressure treatments than for standard treatments, but no differences in maize yield. This research analyses the effect of maize canopy water partitioning on irrigation performance indexes (CUC and wind drift and evaporation losses, WDEL). Three irrigation treatments were considered, based on the working pressure: 1) A standard brass impact sprinkler operating at a pressure of 300 kPa (CIS300); 2) A standard brass impact sprinkler operating at a pressure of 200 kPa (CIS200); and 3) A modified plastic impact sprinkler (with a deflecting plate attached to the drive arm) operating at a pressure of 200 kPa (DPIS200). Irrigation performance was measured using a catch-can network located above the maize canopy (CUCac, WDELac) along the whole crop season and using stemflow and throughfall devices below the maize canopy (CUCbc, WDELbc) in eight irrigation events. Maize growth, yield and its components were measured. Under low-wind and fully developed canopy conditions (a frequent situation for maize irrigation), CUCbc resulted higher than CUCac for the low-pressure treatments, while the opposite was observed for the standard pressure treatment. Maize canopy partitioning reduces the differences in irrigation performance indexes between pressure treatments, explaining why there are no differences in grain yield between them. Caution should be used when measuring sprinkler irrigation performance above tall canopies, since the elevation of the catch-cans and the crop canopy partitioning affect performance estimations.

Low-pressure assisted solution synthesis of CH3NH3PbI3-xClx perovskite solar cells

During the preparation of perovskite film, the common one-step method always generates an island-like structure. Large exposed areas lead to direct contact between positive and negative electrodes. Thus, the photoelectric performance is seriously deteriorated. Here, a low-pressure assisted method was introduced to fabricate dense halide perovskite films. The crystalline quality of the films was investigated by X-ray diffraction (XRD) spectroscopy. The film morphology and the device structure were characterized by atomic force microscope (AFM) and field emission scanning electron microscopy (FESEM). The effects of film quality on charge transport were discussed. After low-pressure treatment, the open-circuit voltage (Voc), short-circuit photocurrent (Jsc), fill factor (FF) and power conversion efficiency (PCE) for the device were improved to 0.755 V, 20.045 mA cm−2, 0.52% and 7.9%, respectively. The optimized and centrally distributed performance parameters illustrate that the low-pressure assisted method can be used to improve the quality and uniformity of perovskite films.

Regulatory network analysis of hypertension and hypotension microarray data from mouse model

ABSTRACTWe aimed to identify the potential genes related to blood pressure regulation and screen target genes for high blood pressure (BPH) and low blood pressure (BPL) treatment. The GSE19817 microarray dataset, which included the aorta, liver, heart, and kidney samples from BPH, BPL, and normotensive mice, was downloaded from the Gene Expression Omnibus. Principal component analysis (PCA) was performed based on the entire expression profile. Differentially expressed genes (DEGs) were screened, followed by pathway enrichment analysis. Finally, gene regulatory networks were constructed based on BPH-related and BPL-related DEGs in the aorta, liver, heart, and kidney samples. As a result, DEGs were screened within their respective tissues due to high heterogeneity of different tissues. Totally, 2,726 BPH-related DEGs and 2,472 BPL-related DEGs were screened, which were mainly enriched in pathways such as immune response. The topology data of gene regulatory networks constructed by DEGs in the heart, kidney, and liver were similar than that in aorta. Finally, among BPH-related DEGs, Sept6 and Pigx were found in the top 10 differentially regulated DEGs by comparing the BPH-related DEGs of the aorta with the DEGs of the other 3 tissues in the regulatory network. Although among the top 10 differentially regulated BPL-related DEGs, no common differentially regulated DEGs were found, Wif1, Urb2, and Gtf2ird1 were found among the top ten DEGs in the three tissues other than the kidney tissue. Sept6 and Pigx might participate in the pathogenesis of BPH, whereas Gtf2ird1, Urb2, and Wif1 might be critical target genes for BPL treatment.

The application of low pressure storage to maintain the quality of zucchinis

ABSTRACTZucchini (Cucurbita pepo var. cylindrica) were stored at low pressure (4 kPa) at 10°C at 100% relative humidity for 11 days. Fruit quality was examined upon removal and after being transferred to normal atmosphere (101 kPa) at 20°C for three days. Zucchinis stored at low pressure exhibited a 50% reduction in stem-end browning compared with fruit stored at atmospheric pressure (101 kPa) at 10°C. The benefit of low pressure treatment was maintained after the additional three days storage at normal atmospheric pressure at 20°C. Indeed, low pressure treated fruit transferred to regular atmosphere 20°C for three days possessed a significantly lower incidence of postharvest rot compared to fruit stored at regular atmospheric pressure at 10°C. Zucchinis stored at low pressure showed higher levels of acceptability (28% and 36%, respectively) compared to fruit stored at regular atmospheres at 10°C for both assessment times.