Performance analysis of two typical greenhouse lettuce production systems: Commercial hydroponic production and traditional soil cultivation

Introduction: Due to the shortage of land and water resource, optimization of systems for production in commercial greenhouses is essential for sustainable vegetable supply. The performance of lettuce productivity and the economic benefit in greenhouses using a soil-based system (SBS) and a hydroponic production system (HPS) were compared in this study. Methods: Experiments were conducted in two identical greenhouses over two growth cycles (G1 and G2). Three treatments of irrigation volumes (S1, S2, and S3) were evaluated for SBS while three treatments of nutrient solution concentration (H1, H2, and H3) were evaluated for HPS; the optimal levels from each system were then compared. Results and discussion: HPS was more sensitive to the effects of environmental temperature than SBS because of higher soil buffer capacity. Compared with SBS, higher yield (more than 134%) and higher water productivity (more than 50%) were observed in HPS. We detected significant increases in ascorbic acid by 28.31% and 16.67% and in soluble sugar by 57.84% and 32.23% during G1 and G2, respectively, compared with SBS. However, nitrate accumulated in HPS-grown lettuce. When the nutrient solution was replaced with fresh water 3 days before harvest, the excess nitrate content of harvested lettuce in HPS was removed. The initial investment and total operating cost in HPS were 21.76 times and 47.09% higher than those in SBS, respectively. Consideration of agronomic, quality, and economic indicators showed an overall optimal performance of the H2 treatment. These findings indicated that, in spite of its higher initial investment and requirement of advanced technology and management, HPS was more profitable than SBS for commercial lettuce production

A Large Portal Vein: A Rare Finding of Recent Portal Vein Thrombosis

Acute portal vein thrombosis (PVT) is rarely encountered by clinicians. The most common manifestation of acute PVT is sudden onset of abdominal pain. A computed tomography scan without contrast often shows a high-density material in the portal vein. After injection of contrast agents, absence of luminal enhancement and enlargement of the obstructed portal vein are shown. In this case report, we demonstrated a rare computed tomography finding in which the diameter of the main portal vein was enormously distended to 3-fold that of the aorta in a patient with recent PVT. Despite thrombolysis and anticoagulation were immediately given, portal venous recanalization was not achieved in the patient. After 5 years, variceal bleeding and ascites occurred and liver function had persistently deteriorated. Finally, he died of progressive liver failure. Considering this case, we suggest that an early decision for invasive interventional treatment might be necessary to both increase the rate of portal venous recanalization and improve prognosis, as anticoagulation and thrombolysis therapy failed to recanalize recent PVT

Protective effect of Saussurea involucrata polysaccharide against skin dryness induced by ultraviolet radiation

Background: Exposure to ultraviolet B (UVB) radiation can damage the epidermis barrier function and eventually result in skin dryness. At present, little work is being devoted to skin dryness. Searching for active ingredients that can protect the skin against UVB-induced dryness will have scientific significance.Methods:Saussurea involucrata polysaccharide (SIP) has been shown to have significant antioxidant and anti-photodamage effects on the skin following UVB irradiation. To evaluate the effect of SIP on UVB-induced skin dryness ex vivo, SIP-containing hydrogel was applied in a mouse model following exposure to UVB and the levels of histopathological changes, DNA damage, inflammation, keratinocyte differentiation, lipid content were then evaluated. The underlying mechanisms of SIP to protect the cells against UVB induced-dryness were determined in HaCaT cells.Results: SIP was found to lower UVB-induced oxidative stress and DNA damage while increasing keratinocyte differentiation and lipid production. Western blot analysis of UVB-irradiated skin tissue revealed a significant increase in peroxisome proliferator-activated receptor-α (PPAR-α) levels, indicating that the underlying mechanism may be related to PPAR-α signaling pathway activation.Conclusions: By activating the PPAR-α pathway, SIP could alleviate UVB-induced oxidative stress and inhibit the inflammatory response, regulate proliferation and differentiation of keratinocytes, and mitigate lipid synthesis disorder. These findings could provide candidate active ingredients with relatively clear mechanistic actions for the development of skin sunscreen moisturizers

Effect of Pore Structure on CO2 Adsorption Performance for ZnCl2/FeCl3/H2O(g) Co-Activated Walnut Shell-Based Biochar

Walnut shell is a very potential biochar precursor because of its wide source, low cost, and easy structure modification. In this paper, the co-activation method of FeCl3, ZnCl2 and H2O(g) was adopted to prepare walnut shell-based biochar with high microporosity and the effect of pore structure on CO2 adsorption performance at different temperatures was investigated. The prepared biochar had a larger specific surface area (2647.8 m2 g−1), satisfactory micropore area (2008.7 m2 g−1) and high total pore volume (2.58 cm3 g−1). At 273 K and 298 K, its CO2 adsorption capacity was 4.79 mmol g−1 and 3.20 mmol g−1, respectively. Particularly, CO2 adsorbed uptake on biochar was strongly sensitive to their narrow micropore volume, instead of the total specific surface area, total pore volume, and micropore specific surface area. The optimal pore size beneficial for CO2 adsorption was 0.33–0.82 nm at 273 K, but the optimal pore size was 0.33–0.39 nm at 298 K. It provides theoretical guidance for future material preparation and selection, and FeCl3, ZnCl2 and H2O(g) may be effective biochar activators

Peak uplift resistance of offshore slender structures shallowly buried in the sloping seabed considering wave actions

The current practice for the pipe-soil interaction mainly focuses on the pipelines which are buried in the level ground, and ocean waves are rarely considered. However, sloping topographies and wave actions are often encountered by offshore slender structures. This study numerically investigated their peak uplift resistances, taking multiple factors, i.e., the slope effect and wave effect, into account simultaneously. The numerical model was first verified by the available analytical and experimental results. It was found that the normalized peak uplift resistance decreases as the slope angle increases, especially for smaller burial ratios. The presence of wave troughs weakens the traditional peak uplift resistance. For the given burial ratio and slope angle, the reduction in the peak uplift resistance increases almost linearly with the local wave steepness. For steeper slopes and smaller burial ratios, this reduction becomes larger because of more intense upward seepage. The effects of local relative water depth and wave period were also studied. Finally, a preliminary formula for the reduction in the peak uplift resistance of shallowly-buried offshore slender structures was proposed to consider the slope effect and wave effect

Chiral Catalysis at the Water/Oil Interface

The unique physicochemical properties of water as a solvent have attracted great interest from synthetic chemists for many years, and tremendous research progress on chemical reactions under aqueous conditions has been reported. Among them, catalytic asymmetric reactions have also been demonstrated and water turns out to not only be a unique solvent but also participate in the reactions. In this Perspective, we summarize and discuss recent advances in chiral catalysis at the water/oil interface. Emphasis is placed on the concepts/approaches used in chiral organocatalysis and metal catalysis

Asymmetric Catalytic 1,2-Hydroperoxidation of Isatin-Derived Ketimine with Hydrogen Peroxide in the Crowding Environment of PEGs

The first enantioselective catalytic 1,2-hydroperoxidation has been achieved in the presence of PEG-600 using an acid–base bifunctional chiral squaramide as the organocatalyst, affording a range of enantioenriched α-<i>N</i>-substituted hydroperoxides bearing an oxindole moiety with excellent stereoselectivities (up to 99% ee)