Progress of metabolic engineering for the production of eicosapentaenoic acid.

Eicosapentaenoic Acid (EPA) is an essential ω-3 polyunsaturated fatty acid for human health. Currently, high-quality EPA production is largely dependent on the extraction of fish oil, but this unsustainable approach cannot meet its rising market demand. Biotechnological approaches for EPA production from microorganisms have received increasing attention due to their suitability for large-scale production and independence of the seasonal or climate restrictions. This review summarizes recent research on different microorganisms capable of producing EPA, such as microalgae, bacteria, and fungi, and introduces the different EPA biosynthesis pathways. Notably, some novel engineering strategies have been applied to endow and improve the abilities of microorganisms to synthesize EPA, including the construction and optimization of the EPA biosynthesis pathway, an increase in the acetyl-CoA pool supply, the increase of NADPH and the inhibition of competing pathways. This review aims to provide an updated summary of EPA production.

Development and validation of the Sources of Meaning in Life Scale for the Elderly in China.

OBJECTIVES: People who find meaning in life can endure 'any' pain. However, there were no tools to investigate elderly individuals' sources of meaning in life in China. This study aimed to develop the Sources of Meaning in Life Scale for the Elderly (SMSE), and examine the validation and reliability in Chinese elderly. METHODS: A 43-item pool of SMSE was formed by combining the preliminary interview and literature review. A cross-sectional survey of 627 elderly people was then conducted in two community health service centers, two hospitals, and two nursing homes in Guangzhou by the convenience sampling method. Test-retest reliability was assessed with 24 elderly persons. RESULTS: Six dimensions, containing family (four items), social support (four items), value (seven items), life security (four items), personal development (four items), and leisure activity (five items) explained 62.16% of the variance in total. Confirmatory factor analysis model fitting indices were χ2 = 694.652, df = 330, χ2/df = 2.105, SRMR = 0.0695, GFI = 0.853, IFI = 0.905, TLI = 0.889, CFI = 0.903, and RMSEA = 0.062. The Cronbach's alpha value of the scale was 0.924, while that of each dimension was between 0.727 and 0.870. The inter-class correlation (ICC) of the scale was 0.856. CONCLUSION: The SMSE has good reliability and validity that can be used to evaluate the sources of meaning and meaning in life for the elderly.

The direct and indirect effect of event severity, social support, and optimism on stress-related growth in emerging adults.

Stress-related growth (SRG) can be understood as stressful experiences that act as catalysts for positive life changes. Although less severe than typical 'trauma,' some daily obstacles may nevertheless derail faith and intentions, produce distress, result in a demand for reflection, and provide a possibility for SRG. This study examined the direct and indirect effects of event severity, social support, and optimism on SRG among emerging adults attending college in China. A convenience sample of 365 college students, ranging from 18 to 24 years old, completed surveys on event severity, social support, optimism, and SRG. We applied structural equation modeling and bootstrapping to explore optimism in the mediation model. Results demonstrated that event severity and social support have direct and indirect effects on SRG through a partial mediation effect of optimism. The results indicate that interventions targeting optimism might be an effective approach to improving SRG among college students in China.

Psychometric properties of the Chinese version of the Stress-Related Growth Scale: Short Form in undergraduate nursing students.

In this study, we examined the psychometric properties of the Chinese version of the Stress-Related Growth Scale-Short Form (SRGS-SF) for undergraduate nursing students. Using a cross-sectional design, a convenience sample of 253 undergraduate nursing students was included in this study. Half of the sample (n = 126) was randomly selected to explore the factorial structure of the SRGS-SF via exploratory factor analysis. The rest of the sample (n = 127) was selected to confirm the structure via confirmatory factor analysis. The results showed that the Chinese version of the SRGS-SF consisted of two factors: interpersonal and intrapersonal growth. The scale also had the power to discriminate between undergraduate nursing students with high and low levels of stress-related growth (SRG). The internal consistency and stability of the scale were also adequate. The Chinese version of the SRGS-SF is a valid and reliable measurement for assessing SRG among undergraduate nursing students. One suitable application would be the evaluation of the process underpinning SRG and the effectiveness of interventions.

Mediating effects of meaning in life on the relationship between family care, depression, and quality of life in Chinese older adults.

Background: The study explored sources of meaning in older adults and the action path among family care, meaning in life, quality of life, and depression. Materials and methods: We investigated 627 older adults using the Sources of Meaning in Life Scale for the Elderly (SMSE), the Family Care Index (APGAR), the Center for Epidemiological Studies Depression Scale-10 (CES-D-10), and the EuroqOL-5 Dimensions (EQ-5D). Results: Scores categorized 454 older adults with good family function, 99 with moderate, and 47 with severe family dysfunction; 110 older adults had depression. The structural equation model showed that family care affected the quality of life and depression by influencing meaning, and depression had a significant negative effect on the quality of life (P < 0.05). The model was a good fit for the data (χ2/df = 3.300, SRMR = 0.0291, GFI = 0.975, IFI = 0.971, TLI = 0.952, CFI = 0.971, RMSEA = 0.062). Conclusion: Meaning in life is an intermediary factor that affects depression and quality of life in older adults. Family care had a significant positive impact on SMSE and a negative influence on depression. The SMSE effectively clarifies the sources of meaning in life and can be used to improve meaning and promote mental health in older adults.

Exosomes derived from human umbilical cord mesenchymal stem cells alleviate Parkinson's disease and neuronal damage through inhibition of microglia.

Microglia-mediated inflammatory responses have been shown to play a crucial role in Parkinson's disease. In addition, exosomes derived from mesenchymal stem cells have shown anti-inflammatory effects in the treatment of a variety of diseases. However, whether they can protect neurons in Parkinson's disease by inhibiting microglia-mediated inflammatory responses is not yet known. In this study, exosomes were isolated from human umbilical cord mesenchymal stem cells and injected into a 6-hydroxydopamine-induced rat model of Parkinson's disease. We found that the exosomes injected through the tail vein and lateral ventricle were absorbed by dopaminergic neurons and microglia on the affected side of the brain, where they repaired nigral-striatal dopamine system damage and inhibited microglial activation. Furthermore, in an in vitro cell model, pretreating lipopolysaccharide-stimulated BV2 cells with exosomes reduced interleukin-1ß and interleukin-18 secretion, prevented the adoption of pyroptosis-associated morphology by BV2 cells, and increased the survival rate of SH-SY5Y cells. Potential targets for treatment with human umbilical cord mesenchymal stem cells and exosomes were further identified by high-throughput microRNA sequencing and protein spectrum sequencing. Our findings suggest that human umbilical cord mesenchymal stem cells and exosomes are a potential treatment for Parkinson's disease, and that their neuroprotective effects may be mediated by inhibition of excessive microglial proliferation.

Flavonoid glycosides from the nectar of Camellia reticulata Lindl.

The nectar of Camellia reticulata Lindl. contains sugar, amino acids and other nutritional components, suggesting that it could be developed for food and food additives. To understand the effects of the nectar on human health, we investigated its chemical constituents. Two new flavonoid glycosides, cameretiins A and B (1 and 2), and two known flavonoid glycosides, kaempferol 3-O-(2''-O-E-p-coumaroyl)-ß-D-glucopyranoside (3) and tiliroside (4) were obtained from the nectar of Camellia reticulata Lindl. Their structures were determined based on analysis of their spectroscopic data and by comparison with 1D NMR spectroscopic data of known compounds reported in the literature. Compounds (1-4) were first isolated from the nectar of Camellia reticulata Lindl.

Experimental Study of the Propagation Process of Dissection Using an Aortic Silicone Phantom.

BACKGROUND: The mortality of acute aortic dissection (AD) can reach 65~70%. However, it is challenging to follow the progress of AD formation. The purpose of this work was to observe the process of dissection development using a novel tear-embedded silicone phantom. METHODS: Silicone phantoms were fabricated by embedding a torn area and primary tear feature on the inner layer. CT scanning and laser lightening were conducted to observe the variations in thickness and volume of the true lumen (TL) and false lumen (FL) during development. RESULTS: The model with a larger interlayer adhesion damage required a lower pressure to trigger the development of dissection. At the initiation stage of dissection, the volume of TL increased by 25.5%, accompanied by a 19.5% enlargement of tear size. The force analysis based on the change of tear size verified the deduction of the process of interlaminar separation from the earlier studies. CONCLUSIONS: The primary tear and the weakening adhesion of the vessel layers are key factors in AD development, suggesting that some forms of primary damage to the arterial wall, in particular, the lumen morphology of vessels with straight inner lumen, should be considered as early risk predictors of AD.

A Brush-Spin-Coating Method for Fabricating In Vitro Patient-Specific Vascular Models by Coupling 3D-Printing.

PURPOSE: In vitro patient-specific flexible vascular models are helpful for understanding the haemodynamic changes before and after endovascular treatment and for effective training of neuroendovascular interventionalists. However, it is difficult to fabricate models of overall unified or controllable thickness using existing manufacturing methods. In this study, we developed an improved and easily implemented method by combining 3D printing and brush-spin-coating processes to produce a transparent silicone model of uniform or varied thickness. METHODS: First, a water-soluble inner-skeleton model, based on clinical data, was printed on a 3D printer. The skeleton model was subsequently fixed in a single-axis-rotation machine to enable continuous coating of silicone, the thickness of which was manually controlled by adsorption and removal of excess silicone in a brush-spinning operation. After the silicone layer was solidified, the inner skeleton was further dissolved in a hot water bath, affording a transparent vascular model with real geometry. To verify the controllability of the coating thickness by using this method, a straight tube, an idealised aneurysm model, a patient-specific aortic arch model, and an abdominal aortic aneurysm model were manufactured. RESULTS: The different thicknesses of the manufactured tubes could be well controlled, with the relative standard deviations being 5.6 and 8.1% for the straight and aneurysm tubes, respectively. Despite of the diameter changing from 33 to 20 mm in the patient-specific aorta, the thickness of the fabricated aortic model remains almost the same along the longitudinal direction with a lower standard deviation of 3.1%. In the more complex patient-specific abdominal aneurysm model, varied thicknesses were realized to mimic the measured data from the CT images, where the middle of the aneurysm was with 2 mm and abdominal aorta as well as the iliac arteries had the normal thickness of 2.3 mm. CONCLUSION: Through the brush-spin-coating method, models of different sizes and complexity with prescribed thickness can be manufactured, which will be helpful for developing surgical treatment strategies or training neuroendovascular interventionalists.

[Distribution and Potential Risk of Organochlorine Pesticides in the Soil of a Submerged Area Around Miyun Reservoir].

Soil samples collected from a submerged area around Miyun Reservoir were analyzed for organochlorine pesticide (OCP) residues using GC-MS. The distribution characteristics and possible sources of OCPs were studied, as well as the potential ecological risk. The results showed the following:① the residuals of OCPs in the surface soil were mainly hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs), and the average contents of HCHs and DDTs were 1.74 ng·g-1 and 1.01 ng·g-1, respectively. In comparison with other lakes and reservoirs in China, the mean value of DDT content of the soil samples from Miyun Reservoir was slightly less, whereas the mean value of HCH content was similar to other waterbodies. ② There was a distinct spatial distribution of OCPs in soils of the submerged area. Specifically, the OCP content in the water-land interlaced soil was generally higher, with distinct differences to the water or in land. In the eastern region of the reservoir and in the Chaohe River inflow area, the residues of OCPs were mainly DDTs, as was the case for the submerged soils of small isolated watersheds. The OCPs in the submerged area of the northern reservoir and the western central reservoir were mainly γ-HCH residues, while HCH and DDT residues were found in high proportions in the flooded area where the Baihe River inflows. These patterns were related to sources of pollutants; ③ the source analysis showed that sources of HCHs could be related to lindane input, while DDTs mainly derived from the early residues in the environment; ④ there was low ecological risk from OCPs in most of the samples, and a potential risk from DDT in the Baihe inflow area and in the central submerged zone of the western reservoir.

Full-Reference Stability Assessment of Digital Video Stabilization Based on Riemannian Metric.

Assessing the quality of the motion stability is important to evaluating the performance of video stabilization algorithms. This paper presents a novel quality assessment scheme for the video motion stability in a full-reference (FR) manner. Given ideally stable videos and their corresponding shaky videos, our method measures the geodesic distance between motion paths of the stable and the stabilized videos. Due to the use of the Riemannian metric defined on the manifold of spatial transformations, our method enables the intrinsic and faithful measurement on pairwise motion disparities. To facilitate the FR assessment, a data set of stable and shaky videos is constructed by directly capturing realistic stable/shaky videos with a customized device. Then, digital video stabilization algorithms can be run on shaky videos to obtain the stabilized sequence of frames, whereupon their performances are evaluated by using our stability assessment. The experiments demonstrate that our stability assessment gains good concordance with the subjective assessment.

Assessment and Predictors of Grief Reactions among Bereaved Chinese Adults.

BACKGROUND: The Texas Revised Inventory of Grief-Present Scale (TRIG-Present) is a widely used tool to measure grief. Most existing research related to the assessment and characteristics of grief has been conducted sampling bereaved Western subjects and, as such, limited information is available on the experience of grief in Chinese samples. OBJECTIVE: This study aims to validate the Chinese version of the TRIG-Present (TRIG-Present-C) and explore the predictors of grief among bereaved adults in China. METHODS: Responses from 460 bereaved Chinese adults were collected through an online survey. Subjects completed a specially developed questionnaire covering demographic data/loss-related variables, the TRIG-Present-C, and Center for Epidemiologic Studies Depression Scale (CES-D-9). RESULTS: Confirmatory factor analysis validates the original one-factor structure. The overall content validity index is equal to 1.0. Significant correlations were observed, with CES-D-9 and factor subscales (r ranged from -0.228 to 0.607, p < 0.05) indicating the convergent validity. The TRIG-Present-C scores distinguished grieving individuals from those experiencing unanticipated death and those where death was anticipated. The internal consistency is satisfactory (Cronbach's α = 0.957). In multiple regression analyses, with grief severity as the dependent variable, 28.6% of the variance was explained by religious belief, the immediacy of the loss, the loss of a first-degree relative, and where the deceased was relatively young. CONCLUSIONS: The TRIG-Present-C scale is a reliable and valid instrument for assessing grief reaction among bereaved Chinese adults. Religious belief, loss of a first-degree relative, where the deceased was relatively young, and the immediacy of loss were associated with higher levels of grief.