Flexible graphene aerogel based composite phase change film exhibits efficient solar-thermal conversion ability for intelligent wearable personal thermal management devices.
Display omitted
•The ...flexible phase change film includes functional graphene with paraffin wax.•The PCM film possesses excellent flexibility and phase change properties.•This film exhibits superior cycle and solar-thermal conversion performances.
Developing phase change materials (PCMs) with solar-thermal energy conversion and storage for wearable personal thermal management is of significance but challenging, due to the difficulty of overcoming the liquid phase leakage, weak light adsorption, and solid phase rigidity of conventional phase change materials. In this work, a novel flexible graphene aerogel based composite phase change film (CPCF) has been successfully designed and constructed. In this CPCF, the introduction of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) can strengthen the porous framework of graphene aerogel (GA) and endow the graphene aerogel film (GAF) with superior flexibility. The final CPCF has been obtained by impregnating paraffin wax (PW) into the GAF supporting matrix. This GAF-PW CPCF behaves excellent thermal property, long-term cycle stability, advanced flexibility, and outstanding solar-thermal conversion ability. The phase change enthalpy of the GAF-PW CPCF can reach 154.64 J/g and stay almost unchanged even after 500 heating-cooling cycles. Most importantly, the solar-thermal conversion efficiency of the GAF-PW CPCF is evaluated to be 95.98%, indicating its superior ability to convert solar energy into thermal energy. The flexible GAF-PW CPCF can be easily attached on a human model to demonstrate its advanced performance of wearable thermal management. This flexible CPCF developed in this work exhibits great potential to be applicable in the fields of wearable personal thermal management, providing a promising direction for the development of wearable fabric to enhance the adaptability of human body in cold environment.
At present, the relationship between thyrotropin (TSH) and free thyroxine (FT4) in relation to postmenstrual age (PMA) in preterm infants is still unclear, and there is no reliable standard thyroid ...hormone reference ranges, resulting in different diagnostic criteria for congenital hypothyroidism been used by different newborn screening programs and different countries.
To investigate the relationship between TSH/FT4 and PMA in very preterm infants (VPIs) born with gestational age (GA) <32 weeks and to derive thyroid function reference charts based on PMA.
A prospective cohort study was performed on VPIs born with GA<32 weeks and born in or transferred to the 27 neonatal intensive care units from January 1, 2019 to December 31, 2019. Serial TSH and FT4 values were measured at the end of each week during the first month after birth and also at PMA36 weeks, PMA40 weeks and at discharge, respectively. The 2.5th, 5th, 50th, 95th, and 97.5th percentiles of TSH and FT4 of different PMA groups were calculated to draw the percentile charts based on PMA.
1,093 preterm infants were included in this study. The percentile charts of TSH and FT4 levels based on PMA were drawn respectively, and the result indicated that the percentile charts of TSH values were gradually increased initially and then decreased with increasing PMA. The 97.5th percentile chart reached the peak at PMA30 weeks (17.38μIU/ml), and then decreased gradually, reaching the same level as full-term infants (9.07μIU/ml) at PMA38-40 weeks. The 2.5th percentile chart of FT4 was at its lowest point at PMA26-27 weeks (5.23pmol/L), then increased slowly with PMA and reached the same level as full-term infants at PMA38-40 weeks (10.87pmol/L). At PMA36 weeks, the reference intervals of the 2.5th to 97.5th percentiles of TSH and FT4 were 1.18-12.3μIU/ml and 8.59-25.98pmol/L, respectively.
The percentile charts of TSH and FT4 in VPIs showed characteristic change with PMA. The results prompt that age-related cutoffs, instead of a single reference range, might be more useful to explain the thyroid function of VPIs. And repeated screening is necessary for preterm infants.
The Chinese bush cricket, Gampsocleis gratiosa, has a long history as a pet in China. To date, the sequencing of its whole genome is unavailable as a non‐model organism. Transcriptomic information is ...also scarce for this species. The G. gratiosa transcriptome was sequenced using Illumina HiSeq 2000 paired‐end sequencing technology. In total 52 million clean reads with an average length of 90 bp were generated, which produced 74,821 unigenes with a mean length of 580 bp and an N50 length of 759 bp. In total 29,674 (39.66%) unigenes were successfully annotated against the NR, NT, Swiss‐Prot, Gene Ontology (GO), Clusters of Orthologous Groups of proteins (COGs) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Further functionally classified of unigenes against GO, COGs and KEGG found that a total of 11,935 (19.95%) unigenes were categorized into 61 GO terms, 19,576 unigenes were clustered into 25 COG functional categories and 17,971 unigenes were assigned to 258 KEGG pathways. In addition, 2093 microsatellite loci were identified, of which 591 loci had flanking sequences suitable for polymerase chain reaction (PCR) primer design. The transcriptome profile of G. gratiosa contributed to the accumulation of orthopteran genomic data, and the microsatellite loci provided useful tools for future studies of this and other closely related Gampsocleis species.
A novel high-throughput assay for measuring antioxidant capacity against superoxide anion has been developed and validated. In this assay, hydroethidine (HE), a fluorescent probe, is oxidized by ...superoxide anion generated by xanthine and xanthine oxidase and increases its fluorescence intensity. Therefore, the inhibition of loss of HE's fluorescence intensity in the presence of antioxidant is an index of antioxidant capacity. The result is expressed as superoxide dismutase (SOD) equivalent. Unlike other probes, such as tetrazolium and lucigenin, one major advantage of this assay is that the use of HE is not prone to artifact. The method was rigorously validated through linearity, precision, accuracy, and ruggedness. The linear range, limit of quantitation (LOQ), and limit of detection (LOD) are 0.22-3.75 units/mL, 0.30 unit/mL, and 0.10 unit/mL, respectively. A wide variety of phenolic compounds and fruit extracts were analyzed.
Purpose
In the advertising strategy called pseudo-ownership advertising appeal, ownership-implying language (e.g. my, our or your) is used to induce consumers’ “ownership” of a brand. This study aims ...to investigate the influence of pseudo-ownership advertising appeal on brand psychological ownership and consequent brand attitude, purchase intention and choice. This study also assessed the relative effectiveness of different types of possessive pronouns in different customer segments.
Design/methodology/approach
Four experiments, involving both students and non-students, were conducted to test the hypotheses. Experiments 1 and 2 investigated the effects of the first-person singular and plural possessive pronouns (“my” and “our”) on psychological ownership and on brand attitude, purchase intention and choice. Experiment 3 investigated the interacting effects of self-construal (independent vs interdependent) and possessive pronoun (singular vs plural) on psychological ownership and brand attitudes. Experiment 4 investigated the interacting effects of customer type (potential vs current) and possessive pronoun (first-person vs second-person) on psychological ownership and brand attitudes.
Findings
Pseudo-ownership advertising appeal resulted in the development of brand psychological ownership, as well as inducing favorable attitudes, purchase intentions and brand choice. Furthermore, consumers with interdependent self-construal developed stronger psychological ownership when pseudo-ownership advertising appeal incorporated plural possessive pronouns, and consumers with independent self-construal developed stronger psychological ownership when pseudo-ownership advertising appeal incorporated singular possessive pronouns. Potential consumers developed stronger psychological ownership when pseudo-ownership advertising appeal incorporated second- vs first-person possessive pronouns, and current consumers developed the same psychological ownership for first- and second-person possessive pronouns.
Originality/value
Possessive pronouns used in advertising can enhance brand psychological ownership. Conditions that moderate the relative effectiveness of first- vs second-person and singular vs plural possessive pronouns on brand psychological ownership and consequential consumer responses can be identified. These findings extend research focusing solely on the self-referencing effects of second-pronoun use (“you”) in advertising on consumer attitudes and behaviors by paying attention to the “ownership” effects of possessive pronouns.
A novel coordination polymer, poly4‐aminopyridinium diaquaμ3‐5‐(carboxylatomethoxy)benzene‐1,3‐dicarboxylatocadmium(II) dihydrate, {(C5H7N2)Cd(C10H5O7)(H2O)2·2H2O}n or {(HpAPy)Cd(OABDC)(H2O)2·2H2O}n ...HpAPy is 4‐aminopyridinium and H3OABDC is 5‐(carboxymethoxy)benzene‐1,3‐dicarboxylic acid, was synthesized under hydrothermal conditions. Single‐crystal analysis revealed that the anionic complex has a centrosymmetric one‐dimensional tubular arrangement. The pyridine N atom of the 4‐aminopyridine molecule is protonated and this cation balances the charge of the tubular anionic coordination polymer. Neighbouring tubes are crosslinked into a three‐dimensional framework through multiple hydrogen bonds involving solvent water molecules and OABDC3− ligands.
Intestinal microbiota has increasingly been recognized as a major determinant of host health due to its critical role in the maintenance of immune homeostasis. An experimental fish model with ...disrupted intestinal microbiota allows us to identify potential strategies for restoring or modulating microbiota composition. The aim of this study was to develop a reliable grass carp model with disrupted intestinal microbiota by treatment with an antibiotic cocktail consisting of vancomycin, enrofloxacin, florfenicol, and metronidazole at different concentrations. To identify the appropriate concentration and exposure time of antibiotic treatment required to disrupt intestinal microbiota, five antibiotic regimens were compared in terms of their effects on intestinal microbiota composition, growth and health status, and histological changes in the intestine, hepatopancreas, and spleen. Antibiotic-induced changes in the expression of inflammation- and apoptosis-related genes in grass carp intestines were also examined. The results revealed that the highest antibiotic concentration over a 28 day period was required to disrupt both luminal and mucosal microbiota through significant expansion of Proteobacteria and suppression of Fusobacteria. Treatment with this regimen induced significant down-regulation of caspase-8, MLCK, ZO-1, IL-17N, and IL-23R, and up-regulation of IL-1β and IL-6 in the intestine, suggesting possible effects on intestinal epithelial tight junction and inflammatory conditions. This treatment did not produce substantial histopathological changes, and was not directly detrimental to growth and health. Therefore, this antibiotic regimen may provide a suitable option to disrupt intestinal microbiota in grass carp. In addition, our study also implies that fish may serve as a promising model for investigating growth-promoting effects of antibiotics, when treated with antibiotics in low doses.
•Antibiotic treatment did not affect alpha diversity of the luminal microbiota.•Antibiotic exposure duration matters more than concentration in disrupting microbiota.•The microbiota composition differed substantially between intestinal content and mucosa.•The growth-promoting effect of low-dose antibiotics was confirmed in grass carp.
Display omitted
•A facile one-step strategy is proposed for synthesizing graphene-based PCMs.•The PCMs maintain a large PEG loading amounts up to 95 wt% without liquid leakage.•The PCMs exhibit a ...high phase transition enthalpy of 163.5 J/g.•The solar-thermal conversion efficiency of the PCMs is as high as 93.7%.
Graphene-based composite phase change materials (PCMs) exhibit great potential applications in the field of solar-thermal energy conversion and storage, recently, due to their attracting capability of endowing the PCMs with superior light absorption ability and preventing the liquid phase leakage during the transition process. However, current synthesis methods of graphene-based composite PCMs usually involve complicated multi‐step procedures, greatly hindering its large-scale preparation for the practical application of the solar-thermal energy utilization technique. Herein, we report a facile and straightforward one-step strategy of constructing graphene-based shape-stable composite PCMs with polyethylene glycol (PEG) in situ filled into a graphene oxide (GO) network structure hydrogel. Using this one-step strategy, we achieve a high PEG loading capacity up to 95 wt% in the graphene-based composite PCMs. The composite PCMs also have a relatively constant phase change enthalpy of 162.8 J/g even after 1000 heating–cooling cycles. Most importantly, the composites exhibit a superior solar-thermal conversion ability with the conversion efficiency as high as 93.7%. Compared with the currently reported synthetic routes, the complicated processing steps are greatly reduced in this one-step synthesis strategy. This work proposes a simple and efficient method of synthesizing graphene-based composite PCMs with superior solar-thermal conversion efficiency, which may have great potential applications in the field of solar-thermal energy conversion and storage.
Display omitted
•A bio-based aromatic s-triazine compound and its epoxy derivate were synthesized.•The bio-based epoxy system showed a record Tg of 300 °C, high strength and modulus.•The bio-based ...epoxy system showed satisfactory intrinsic flame retardancy.
Developing bio-based epoxy resins with high thermal stability and mechanical properties as well as satisfactory intrinsic flame retardancy is of increasing demand, though this has always been limited by the lack of bio-based polyaromatic building blocks. Herein, a simple and universal method was proposed to synthesize an aromatic s-triazine derivative from biomass feedstock, vanillin, and the obtained compound can be employed to construct a bio-based epoxy precursor (THMT-EP). With 4,4′-diaminodiphenyl sulfone (DDS) as curing agent, thanks to the unique structures of aromatic s-triazine, the resulting cured THMT-EP/DDS presented remarkable integrated properties outperforming than commercial petroleum-based bisphenol A epoxy resin (DGEBA), including a record glass transition temperature of 300 °C, as well as a high flexural modulus of 4137 MPa and a flexural strength of 134.2 MPa, which were 120 °C, 53.9% and 14.3% higher than those of DGEBA/DDS, respectively. Furthermore, the cured THMT-EP/DDS also showed excellent intrinsic flame retardancy, passing the V-0 rating in UL-94 test. This study opens an avenue for the synthesis of bio-based feedstocks with rigid aromatic and functional structure, and contributes to the development of bio-based high-performance polymers.
•PEG heat capacities were measured from T = (1.9 to 400) K for the first time.•Thermodynamic functions were calculated based on the heat capacity curve fitting.•Thermal property measurement results ...were compared with previous results.
Phase change materials (PCMs) generally offer high latent heats for a wide range of thermal energy storage technologies. As typical organic PCMs, polyethylene glycol (PEG) has been widely studied due to their high latent enthalpy, non-toxic and non-corrosive natures. However, the thermal properties especially the heat capacities of PEG, which would play a vital role in theoretically and technically investigating PCM thermal performance, have never been studied in a wide temperature region. Herein, we reported the heat capacities of PEG samples with the molar massvarying from 1000 to 20,000 for the first time in the temperature range from (1.9 to 400) K using a combination method of Physical Property Measurement System (PPMS) and differential scanning calorimeter (DSC). Furthermore, the standard molar heat capacity, entropy and enthalpy at 298.15 K and 0.1 MPa were calculated based on the heat capacity curve fitting. Meanwhile, the phase transition temperature and enthalpy, thermal conductivity and thermal stability of these PEG samples were measured using various thermal analysis methods, and these thermal properties were also compared with the previous results.
PDF
