| 1. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Guo, Jing, et al.
(author)
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Pulmonary toxicity and adjuvant effect of di-(2-exylhexyl) phthalate in ovalbumin-immunized BALB/c mice
- 2012
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In: PLOS ONE. - : PLOS. - 1932-6203. ; 7:6
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Journal article (peer-reviewed)abstract
- BACKGROUND: Asthma is a complex pulmonary inflammatory disease, which is characterized by airway hyperresponsiveness, variable airflow obstruction and inflammation in the airways. The majority of asthma is allergic asthma, which is a disease caused by type I hypersensitivity mediated by IgE. Exposures to a number of environmental chemicals are suspected to lead to asthma, one such pollutant is di-(2-ethylheyl) phthalate (DEHP). DEHP is a manufactured chemical that is commonly added in plastic products to make them flexible. Epidemiological studies have revealed a positive association between DEHP exposure and asthma prevalence.METHODOLOGY/PRINCIPAL FINDINGS: The present study was aimed to determine the underlying role of DEHP exposure in airway reactivity, especially when combined with allergen exposure. The biomarkers include pulmonary histopathology, airway hyperresponsiveness (lung function), IgE, IL-4, IFN-γ and eosinophils. Healthy balb/c mice were randomly divided into eight exposure groups (n = 8 each): (1) saline control, (2) 30 µg/(kg•d) DEHP, (3) 300 µg/(kg•d) DEHP, (4) 3000 µg/(kg•d) DEHP, and (5) ovalbumin (OVA)-sensitized group, (6) OVA-combined with 30 µg/(kg•d) DEHP, (7) OVA-combined with 300 µg/(kg•d) DEHP, and (8) OVA-combined with 3000 µg/(kg•d) DEHP. Experimental tests were conducted after 52-day DEHP exposure and subsequently one week of challenge with aerosolized OVA. The principal findings include: (1) Strong postive associations exist between OVA-combined DEHP exposure and serum total IgE (T-IgE), as well as histological findings. These positive associations show a dose-dependent low dose sensitive effect of DEHP. (2) IL-4, eosinophil recruitment and lung function are also indicators for adjuvant effect of DEHP.CONCLUSIONS/SIGNIFICANCE: Our results suggest that except the significant changes of immunological and inflammatory biomarkers (T-IgE, IL-4, IFN-γ and eosinophils), the pulmonary histological (histopathological examination) and physiological (lung function) data also support that DEHP may promote and aggravate allergic asthma by adjuvant effect.
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| 3. |
- Liu, Simin, et al.
(author)
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Taxonomic revision of the Long-tailed RosefinchCarpodacus sibiricuscomplex
- 2020
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In: Journal of Ornithology. - : SPRINGER HEIDELBERG. - 2193-7192 .- 2193-7206. ; 161:4, s. 1061-1070
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Journal article (peer-reviewed)abstract
- The Long-tailed RosefinchCarpodacus sibiricusbreeds in two widely disjunct areas in East Asia. Five subspecies are usually recognized. The plumage differences between different subspecies groups withinC. sibiricusare notable, suggesting it may actually comprise more than one species. However, proper taxonomic assessment has not been carried out, probably in part due to the scarcity and lack of museum specimens of some of these subspecies. In the current study, we re-evaluated the taxonomy of theC. sibiricuscomplex using molecular, acoustic and morphological data. Using mitochondrial DNA, the samples formed two clades, a northern clade (C. s. sibiricus,C. s. ussuriensisandC. s. sanguinolentus) and a southern clade (C. s. henriciandC. s. lepidus). We also revealed thatC. s. ussuriensisandC. s. sanguinolentusare mostly indistinguishable based on mitochondrial markers. This north/south split pattern is congruent with the pattern of plumage differences among north and south taxa. However, no diagnosable differences were found in their songs. We propose synonymizingC. s. ussuriensiswithC. s. sanguinolentus. At the species level, we suggest splitting the complex into two species, with Siberian Long-tailed RosefinchC. sibiricuscomprisingC. s. sibiricusandC. s. sanguinolentus, and Chinese Long-tailed RosefinchC. lepiduscomprisingC. l. henriciandC. l. lepidus.
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| 4. |
- Shi, Feng, et al.
(author)
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Interdecadal to Multidecadal Variability of East Asian Summer Monsoon Over the Past Half Millennium
- 2022
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In: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 127:20
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Journal article (peer-reviewed)abstract
- The East Asian summer monsoon (EASM) plays a crucial role for ecosystems and societies in East Asia past, present, and future. However, substantial uncertainties remain regarding EASM variability on interdecadal to multidecadal timescales because of the short length of instrumental data in East Asia. This study extended the EASM circulation index in the modern meteorological studies to the paleoclimate over the past half-millennium (1470-1998 CE) to reconcile the understanding of the EASM variability in paleoclimate and modern meteorological studies. The EASM index is reconstructed based on the common signal from the three main types of the proxy records (the tree rings, speleothems, and historical documentary data) related to EASM. The reconstructed EASM index captures the simultaneous changes of the "Meiyu precipitation" and the southwesterly anomalies in South China on interdecadal to multidecadal timescales, which is a dynamic pattern visible and well-documented in the modern meteorology. Analysis of the reconstructed EASM index suggests that the interdecadal to multidecadal EASM variability is closely associated with the Pacific-Japan teleconnection pattern, which acts as a bridge between the negative phase of the Pacific Decadal Oscillation and the anomalous anticyclonic circulation over the western North Pacific. It also indicates that the EASM variability over the recent 30 years (1992-2021 CE) falls within the range of natural variability over the past half-millennium.
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| 5. |
- Shi, Feng, et al.
(author)
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Interdecadal to Multidecadal Variability of East Asian Summer Monsoon Over the Past Half Millennium
- 2022
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In: Journal of Geophysical Research - Atmospheres. - : American Geophysical Union (AGU). - 2169-897X .- 2169-8996. ; 127:20
-
Journal article (peer-reviewed)abstract
- The East Asian summer monsoon (EASM) plays a crucial role for ecosystems and societies in East Asia past, present, and future. However, substantial uncertainties remain regarding EASM variability on interdecadal to multidecadal timescales because of the short length of instrumental data in East Asia. This study extended the EASM circulation index in the modern meteorological studies to the paleoclimate over the past half-millennium (1470–1998 CE) to reconcile the understanding of the EASM variability in paleoclimate and modern meteorological studies. The EASM index is reconstructed based on the common signal from the three main types of the proxy records (the tree rings, speleothems, and historical documentary data) related to EASM. The reconstructed EASM index captures the simultaneous changes of the “Meiyu precipitation” and the southwesterly anomalies in South China on interdecadal to multidecadal timescales, which is a dynamic pattern visible and well-documented in the modern meteorology. Analysis of the reconstructed EASM index suggests that the interdecadal to multidecadal EASM variability is closely associated with the Pacific-Japan teleconnection pattern, which acts as a bridge between the negative phase of the Pacific Decadal Oscillation and the anomalous anticyclonic circulation over the western North Pacific. It also indicates that the EASM variability over the recent 30 years (1992–2021 CE) falls within the range of natural variability over the past half-millennium.
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| 6. |
- Shi, Wenming, et al.
(author)
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Urinary phthalate metabolites in relation to childhood asthmatic and allergic symptoms in Shanghai
- 2018
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In: Environment International. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0160-4120 .- 1873-6750. ; 121, s. 276-286
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Journal article (peer-reviewed)abstract
- Background: Few studies can be found on phthalate exposure in relation to childhood asthma and allergic symptoms from Mainland China, where a persistent increase in prevalence of childhood asthma and allergic disease has been observed. Objectives: This study aimed to assess the exposure levels to phthalates and its relationship with asthmatic and allergic symptoms among children in Shanghai, which has the highest prevalence of childhood asthma in Mainland China. Methods: A follow-up study (2013-2014) of 434 children aged 5-10 years was conducted, based on the China, Children, Homes, Health (CCHH) study (2011-2012) in Shanghai, China. Information on asthmatic and allergic symptoms (wheeze, rhinitis, and eczema) were collected using validated questionnaires. Ten phthalate metabolites in morning urine samples were analyzed by high-performance liquid chromatography with triple quadrupole tandem mass spectrometry (HPLC-MS/MS). Multivariable logistic regression was used to estimate the associations between symptoms and urinary phthalate metabolites controlling for demographics, family history of allergic diseases and other covariates. Results: Nine out of 10 phthalate metabolites were detected in all subjects (average detection rate of 93.2%). By multivariable logistic regression analyses, the 4th quartile of Mono-n-butyl phthalate (MnBP) (reference: 1st quartile) had adjusted prevalence odds ratios (aPORs) and 95% confidence intervals (95%CIs) of 2.27(1.06-4.88), 2.14(1.02-4.46) and 2.98(1.19-7.50) for wheeze, rhinitis and eczema, respectively, while those of Mono-isobutyl phthalate (MiBP) were 2.23(1.08-4.62) and 2.96(1.02-8.60) for rhinitis and eczema, respectively. The highest quartile of mono-2-ethyl-5-hydroxyhexyl phthalate(MEHHP) and mono 2 ethyl 5 ox ohexyl phthalate(MEOHP) had aPORs and 95%CIs of 3.10(1.10-8.74) and 2.63(1.02-6.80) for eczema, respectively. By summing up the 4 low molecular weight metabolites (Sigma 4LMWP) and all 9 metabolites (Sigma(9)Total), the highest quartiles of Sigma 4LMWP and Sigma(9)Total were significantly associated with all symptoms. In most of the above associations, a significantly increasing trend from the 1st to the 4th quartile was observed. Subjects with 2 or 3 concomitant symptoms (reference: no symptoms) had significant positive associations with a higher level (the 4th quartile) of phthalate metabolites. Conclusions: Low MW metabolites such as MnBP and MiBP, high MW DEHP and the total amount of phthalate metabolites might have adverse health effects on asthma and allergic symptoms in Chinese children.
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| 7. |
- Tang, Jiaqi, et al.
(author)
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Neurobehavioral changes induced by di(2-ethylhexyl) phthalate and the protective effects of vitamin E in Kunming mice
- 2015
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In: Toxicology Research. - : Royal Society of Chemistry. - 2045-452X .- 2045-4538. ; 4:4, s. 1006-1015
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Journal article (peer-reviewed)abstract
- Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in PVC that may leach into the environment, and has been shown to adversely affect the health of humans and animals. We undertook a study to ascertain the neurotoxicity of DEHP in Kunming mice. This study included three rounds of testing. In the first round, Kunming mice were exposed to different concentrations of DEHP (0, 5, 50, 500 mg kg(-1) per day) after which their cognitive ability was assessed using the Morris water maze (MWM) test. The reactive oxygen species (ROS) content in tissue and the malondialdehyde (MDA) content of brains were also measured. In the second round, vitamin E (50 mg kg(-1) per day) was given daily as an anti-oxidant via the intragastric route. Cognitive deficits and locomotor activity, as well as ROS and MDA contents were tested employing the same methods. In the third round, the depressive mood of mice after DEHP exposure (500 mg kg(-1) per day) was measured using the open field test, the tail suspension test, and the forced swim test. The main findings of this study include: (1) a statistical association exists between DEHP oral exposure and spatial learning (DEHP 500 mg kg(-1) per day) and memory (DEHP 50 mg kg(-1) per day) dysfunction as ascertained by an MWM test of Kunming mice. (2) A statistical association was also found between DEHP oral exposure (50 and 500 mg kg(-1) per day) and oxidative stress (ROS and MDA) of mouse brain tissue. (3) Co-administration of vitamin E (50 mg kg(-1) per day) diminishes the elevation of ROS and MDA induced by DEHP (50 mg kg(-1) per day) from significant levels to non-significant levels. (4) Co-administration of vitamin E (50 mg kg(-1) per day) protects against mouse memory dysfunction induced by DEHP (50 mg kg(-1) per day) from being significant to being not significant. (5) In the 5 mg kg(-1) per day DEHP exposure groups, oxidative stress in brain tissue, and neurobehavioral changes were not found. (6) High dose DEHP exposure (500 mg kg(-1) per day) may induce behavioral despair in mice. Conclusions: These data suggest that DEHP is neurotoxic with regard to cognitive ability and locomotor activity.
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| 8. |
- Wang, Hao, et al.
(author)
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In-situ growth of low-dimensional perovskite-based insular nanocrystals for highly efficient light emitting diodes
- 2023
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In: Light. - : SPRINGERNATURE. - 2095-5545 .- 2047-7538. ; 12:1
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Journal article (peer-reviewed)abstract
- Regulation of perovskite growth plays a critical role in the development of high-performance optoelectronic devices. However, judicious control of the grain growth for perovskite light emitting diodes is elusive due to its multiple requirements in terms of morphology, composition, and defect. Herein, we demonstrate a supramolecular dynamic coordination strategy to regulate perovskite crystallization. The combined use of crown ether and sodium trifluoroacetate can coordinate with A site and B site cations in ABX(3) perovskite, respectively. The formation of supramolecular structure retard perovskite nucleation, while the transformation of supramolecular intermediate structure enables the release of components for slow perovskite growth. This judicious control enables a segmented growth, inducing the growth of insular nanocrystal consist of low-dimensional structure. Light emitting diode based on this perovskite film eventually brings a peak external quantum efficiency up to 23.9%, ranking among the highest efficiency achieved. The homogeneous nano-island structure also enables high-efficiency large area (1 cm(2)) device up to 21.6%, and a record high value of 13.6% for highly semi-transparent ones.
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