•Short hot water (SHW) prevented decay and maintained cucumbers quality.•SHW induced chilling tolerance and antioxidant enzymes in cucumbers.•SWH at 55 °C for 5 min can be used as safe treatment in ...packinghouse.
This study investigated the effects of treating cucumbers with short hot water dipping at 45 (SHW45) and 55 °C (SHW55) for 5 min compared to fruit dipped in 25 °C water (C). The purpose was to alleviate chilling injury, prevent decay, maintain sensory quality and induce antioxidant enzymes during storage. The cucumbers were held at 4 °C for 7, 14 and 21 d and shelf life at 20 °C for 2 and 4 d. Weight loss, appearance, decay, color, firmness, taste, soluble solids content (SSC), chilling injury (CI), total, reducing and non-reducing sugars, phenolics, electrolyte leakage (EL), peroxidase (POD) and catalase (CAT) activity were measured. The results revealed that SHW55 treatment had the lowest weight loss, CI, EL and POD activity, and had the best appearance, color, taste, and the highest CAT activity during cold storage and shelf life compared with C and SHW45. However, no significant effects were found between C, SHW45 and SHW55 on total, reducing sugars and SSC. No decay appeared on cucumber fruit with SHW55 treatment during the storage period. It may be possible to use SHW55 in a packinghouse as a safe commercial treatment to maintain quality, prevent decay and mitigate chilling injury, prolong storage period and possibility to store cucumber fruit at a non-optimal low temperature.
Evaluation of shrinkage strain in long concrete structures such as prestressed concrete box girder bridges is very important for the design of such structures. A wrong evaluation may contribute to ...loss of prestressing force, excessive deflections, cambers and cracking of the structure. It may also affect the durability and serviceability of the structure. The value of shrinkage strain is required during design, far before the construction process. However, realistic evaluation is still a difficult problem because shrinkage strain is influenced by the concrete composition and environmental factors such as humidity and temperature. Therefore, to gain the best evaluation, an experimental program was conducted to measure the shrinkage strain of concrete versus concrete age. Several concrete specimens were collected during pouring of several box girder segments of Tauranga Harbour Link, New Zealand. Variation of shrinkage strain versus concrete age for almost two years of data collection was plotted.
In this article, the dynamics model of a hexacopter equipped with a robotic arm has been formulated using Newton–Euler’s method and its stability was investigated. For disturbances emulation, a ...simplified pendulum method was used. This hexacopter configuration was not covered in scientific papers before. The resulting model is a nonlinear, coupled, and underactuated dynamics model, which includes aerodynamic effects and disturbances because of equipping the hexacopter with a robotic arm. The purpose of the presented article is to offer a comprehensive study of determining the inertia moments of the hexacopter using a simplified pendulum method, taking into consideration the effect of mass distribution and center of gravity changes, which are a result of the continuous movement of the manipulator during the hexacopter motion in the air. The experimental tests were made using SolidWorks application and were evaluated using LabVIEW in order to get a complete view of the disturbances, which were inserted into the dynamics model. The overall aircraft model was driven by four classical proportion, integral, and derivative controllers for the vehicle’s attitude and altitude of a desired trajectory in the space. These controllers were used to get a good understanding of how to evaluate and validate the model to make it an anti-disturbance model, in addition to their ease of design and fast response, but they require development in order to get optimal results. In future, a precise trajectory will be defined, and the controllers will be developed in order to get robust stability using nonlinear techniques and artificial intelligence.
Abstract
Background
Surgeons need guidance regarding appropriate personal protective equipment (PPE) during the COVID-19 pandemic based on scientific evidence rather than availability. The aim of ...this article is to inform surgeons of appropriate PPE requirements, and to discuss usage, availability, rationing and future solutions.
Methods
A systematic review was undertaken in accordance with PRISMA guidelines using MEDLINE, Embase and WHO COVID-19 databases. Newspaper and internet article sources were identified using Nexis. The search was complemented by bibliographic secondary linkage. The findings were analysed alongside guidelines from the WHO, Public Health England, the Royal College of Surgeons and specialty associations.
Results
Of a total 1329 articles identified, 95 studies met the inclusion criteria. Recommendations made by the WHO regarding the use of PPE in the COVID-19 pandemic have evolved alongside emerging evidence. Medical resources including PPE have been rapidly overwhelmed. There has been a global effort to overcome this by combining the most effective use of existing PPE with innovative strategies to produce more. Practical advice on all aspects of PPE is detailed in this systematic review.
Conclusion
Although there is a need to balance limited supplies with staff and patient safety, this should not leave surgeons treating patients with inadequate PPE.
Graphical Abstract
This systematic review provides a comprehensive overview of all the issues surrounding personal protective equipment for surgeons during the COVID-19 pandemic. To overcome this global challenge needs an evidence-based, collaborative, innovative multidisciplinary approach.
Graphical Abstract
Better to be safe than sorry
The effect of melatonin (MT) on potato plants under drought stress is still unclear in the available literature. Here, we studied the effect of MT as a foliar application at 0, 0.05, 0.1, and 0.2 mM ...on potato plants grown under well-watered and drought stressed conditions during the most critical period of early tuberization stage. The results indicated that under drought stress conditions, exogenous MT significantly (
≤ 0.05) improved shoot fresh weight, shoot dry weight, chlorophyll (Chl; a, b and a + b), leaf relative water content (RWC), free amino acids (FAA), non-reducing sugars, total soluble sugars, cell membrane stability index, superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POX), and ascorbate peroxidase (APX) compared to the untreated plants. Meanwhile, carotenoids, proline, methylglyoxal (MG), H
O
, lipid peroxidation (malondialdehyde; MDA) and abscisic acid (ABA) were significantly decreased compared to the untreated plants. These responses may reveal the protective role of MT against drought induced carbonyl/oxidative stress and enhancing the antioxidative defense systems. Furthermore, tuber yield was differentially responded to MT treatments under well-watered and drought stressed conditions. Since, applied-MT led to an obvious decrease in tuber yield under well-watered conditions. In contrast, under drought conditions, tuber yield was substantially increased by MT-treatments up to 0.1 mM. These results may imply that under water deficiency, MT can regulate the tuberization process in potato plants by hindering ABA transport from the root to shoot system, on the one hand, and by increasing the non-reducing sugars on the other hand.
The human coronavirus, SARS-CoV-2, had a negative impact on both the economy and human health, and the emerging resistant variants are an ongoing threat. One essential protein to target to prevent ...virus replication is the viral RNA-dependent RNA polymerase (RdRp). Sofosbuvir, a uridine nucleotide analog that potently inhibits viral polymerase, has been found to help treat SARS-CoV-2 patients. This work combines molecular docking and dynamics simulation (MDS) to test 14 sofosbuvir-based modifications against SARS-CoV-2 RdRp. The results reveal comparable (slightly better) average binding affinity of five modifications (compounds 3, 4, 11, 12, and 14) to the parent molecule, sofosbuvir. Compounds 3 and 4 show the best average binding affinities against SARS-CoV-2 RdRp (- 16.28 ± 5.69 and - 16.25 ± 5.78 kcal/mol average binding energy compared to - 16.20 ± 6.35 kcal/mol for sofosbuvir) calculated by Molecular Mechanics Generalized Born Surface Area (MM-GBSA) after MDS. The present study proposes compounds 3 and 4 as potential SARS-CoV-2 RdRp blockers, although this has yet to be proven experimentally.
Metal additive manufacturing (AM) has been growing remarkably in the past few years. Thanks to the advantages of unmatched flexibility and zero material waste, this clean technology opens the door ...for new design solutions with greater material efficiency, which are not possible through conventional machining techniques. In this paper, we provide a technology overview of metal AM techniques that can be utilized in a wide range of applications, including constructing electrical machines. Different techniques of metal AM are discussed and compared. Additionally, the impact of the material forms (powder/wire) on printing speed and quality are studied. Based on the industrial and technical literature, this paper provides a comprehensive review of metal AM in the fabrication of electrical machines and their applications. This includes the current state of the art and associated benefits of AM in these applications.
The preparation of activated carbon from date stone treated with phosphoric acid was optimized using rotatable central composite design of response surface methodology (RSM). The chemical activating ...agent concentration and temperature of activation plays a crucial role in preparation of large surface area activated carbons. The optimized activated carbon was characterized using thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powder X-ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the larger surface area of activated carbon from date stone can be achieved under optimum activating agent (phosphoric acid) concentration, 50.0% (8.674 mol L−1) and activation temperature, 900 °C. The Brunauer–Emmett–Teller (BET) surface area of optimized activated carbon was found to be 1225 m2 g−1, and thermogravimetric analysis revealed that 55.2% mass of optimized activated carbon was found thermally stable till 900 °C. The leading chemical functional groups found in the date stone activated carbon were aliphatic carboxylic acid salt ʋ(CO) 1561.22 cm−1 and 1384.52 cm−1, aliphatic hydrocarbons ʋ(C–H) 2922.99 cm−1 (C–H sym./asym. stretch frequency), aliphatic phosphates ʋ(P–O–C) 1054.09 cm−1, and secondary aliphatic alcohols ʋ(O–H) 3419.81 cm−1 and 1159.83 cm−1.
Display omitted
•RSM optimization was done for the production of large surface area activated carbon.•Two independent variables with two responses were selected for optimization.•Characterization was done for surface area, morphology and chemical constituents.•Optimized date stone activated carbon achieved surface area 1225 m2 g−1.
Pure polycrystalline BaFe
12
O
19
films have been successfully prepared using a sol–gel method without a buffer layer. The films were annealed at a temperature range of 700 °C to 900 °C in air and ...oxygen for 2 h. An X-ray diffraction analysis showed that films annealed in air at 800 °C and 900 °C crystallized into a single phase. However, the film annealed in oxygen at 900 °C showed the appearance of a non-magnetic phase. The magnetic properties analysis showed films annealed in air surroundings at 800 °C and 900 °C have large coercivity values (5270 Oe, 5086 Oe) and high saturation magnetization values (160 emu/cm
3
, 194 emu/cm
3
), respectively. However, films that were annealed at 800 °C and 900 °C in oxygen surroundings showed high coercivity (940 Oe and 5425 Oe) but low saturation magnetization values (80 emu/cm
3
and 64 emu/cm
3
, respectively).
During the year 2020, 60 samples of black and green tea bags were collected from Jordanian markets. The samples were subjected to multi-residue analysis for 16 carcinogenic polycyclic aromatic ...hydrocarbons (PAHs) which belong to the Environmental Protection Agency (EPA) priority pollutant list and 20 banned organochlorine pesticides (OCPs). A QuEChERs method was developed for the determination of 16 EPA PAHs and OCPs residues using hyphenated gas chromatography-mass spectrometry (GC-MS) for analysis. To minimize the colors of chlorophyll and carotenoids, the concentrated extracts were subjected to 10 mg of activated charcoal for further extraction. The QuEChERs technique has been validated, and the outcomes in terms of linearity, detection limits, quantitation limits, precision, and recovery have been satisfactory. On one hand, none of the examined black and green tea bag samples contained any of the studied OCPs, while the estimated quantities of PAHs, on the other hand, ranged from 280.03 to 486.46 µg kg
−1
, and the amounts of benzoapyrene ranged from 4.85 to 8.56 µg kg
−1
. The light PAHs were predominant in both black and green tea samples (90%), while the contribution of heavy PAHs was much less significant (10%). The incremental lifetime cancer risk (ILCR) was evaluated, and the values for all tea samples have not exceeded the limit value of 10
−6
but ranged from 4.17 × 10
−8
to 0.0158 × 10
−8
, thus indicating a slight potential risk.
PDF
