The high reproducibility of the flow synthesis system enabled accurate investigation of the relationship between reaction conditions and molecular weight in Stille polycondensation of conjugated ...polymers. Here, a conjugated polymer, PTB7, was synthesized in a customized flow reactor using various catalyst and solvent combinations, and their effect on molecular weight was studied. Specifically, common palladium catalysts (Pd(PPh
3
)
4
and Pd
2
(dba)
3
) were screened in three different solvents (toluene, chlorobenzene, and
o
-xylene). A significant difference in molecular weight was observed depending on the type of solvent when using Pd
2
(dba)
3
as a catalyst. It was discovered that the solubility of both the catalyst and PTB7 in the solvent played a critical role in determining the molecular weight of the polymer. By using the Pd
2
(dba)
3
catalyst system, a high number-averaged molecular weight (
M
n
) for PTB7, ranging from 41.7 to 51.5 kDa, was achieved. This was 16 times higher than that obtained with the Pd(PPh
3
)
4
catalyst system in any solvent. However, the Pd(PPh
3
)
4
catalyst system showed high compatibility with dimethylformamide (DMF) co-solvent, and the
M
n
of PTB7 synthesized with the Pd(PPh
3
)
4
catalyst showed a significant increase, ranging from 53.9 to 58.7 kDa, while the
M
n
of PTB7 synthesized with the Pd
2
(dba)
3
catalyst decreased to 10.9- 15.0 kDa. The results can provide valuable guidance for optimizing the reaction conditions in the future synthesis of conjugated polymers in a flow reactor to achieve the desired molecular weight.
The high reproducibility of the flow synthesis system enabled accurate investigation of the relationship between reaction conditions and molecular weight in Stille polycondensation of conjugated polymers.
Public isolated due to the early quarantine regarding coronavirus disease 2019 (COVID-19) increasingly used more social media platforms. Contradictory claims regarding the effect of social media use ...on mental health needs to be resolved. The purpose of the study was to summarise the association between the time spent on social media platform during the COVID-19 quarantine and mental health outcomes (i.e., anxiety and depression).
Studies were screened from the PubMed, Embase, and Cochrane Library databases. Regarding eligibility criteria, studies conducted after the declaration of the pandemic, studies that measured mental health symptoms with validated tools, and studies that presented quantitative results were eligible. The studies after retrieval evaluated the association between time spent on social media platform and mental health outcomes (i.e. anxiety and depression). The pooled estimates of retrieved studies were summarised in odds ratios (ORs). Data analyses included a random-effect model and an assessment of inter-study heterogeneity. Quality assessment was conducted by two independent researchers using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). This meta-analysis review was registered in PROSPERO ( https://www.crd.york.ac.uk/PROSPERO/ , registration No CRD42021260223, 15 June 2021).
Fourteen studies were included. The increase in the time spent using social media platforms were associated with anxiety symptoms in overall studies (pooled OR = 1.55, 95% CI: 1.30-1.85), and the heterogeneity between studies was mild (I
= 26.77%). Similarly, the increase in social media use time was also associated with depressive symptoms (pooled OR = 1.43, 95% CI: 1.30-1.85), and the heterogeneity between studies was moderate (I
= 67.16%). For sensitivity analysis, the results of analysis including only the "High quality" studies after quality assessment were similar to those of the overall study with low heterogeneity (anxiety: pooled OR = 1.45, 95% CI: 1.21-1.96, I
= 0.00%; depression: pooled OR = 1.42, 95% CI: 0.69-2.90, I
= 0.00%).
The analysis demonstrated that the excessive time spent on social media platform was associated with a greater likelihood of having symptoms of anxiety and depression.
Recently, many kinds of printing processes have been studied to fabricate perovskite solar cells (PeSCs) for mass production. Among them, slot-die coating is a promising candidate for roll-to-roll ...processing because of high-throughput, easy module patterning, and a premetered coating system. In this work, we employed mixed lead precursors consisting of PbAc2 and PbCl2 to fabricate PeSCs via slot-die coating. We observed that slot-die-coated perovskite films based on the mixed lead precursors exhibited well-grown and uniform morphology, which was hard to achieve by using only a single lead source. Consequently, PeSCs made with this precursor system showed improved device performance and reproducibility over single PbAc2. Lastly, a large-area module with an active area of 10 cm2 was fabricated with a power conversion efficiency of 8.3%.
Perovskite solar cells (PeSCs) have been considered one of the competitive next generation power sources. To date, light-to-electric conversion efficiencies have rapidly increased to over 10%, and ...further improvements are expected. However, the poor device reproducibility of PeSCs ascribed to their inhomogeneously covered film morphology has hindered their practical application. Here, we demonstrate high-performance PeSCs with superior reproducibility by introducing small amounts of N-cyclohexyl-2-pyrrolidone (CHP) as a morphology controller into N,N-dimethylformamide (DMF). As a result, highly homogeneous film morphology, similar to that achieved by vacuum-deposition methods, as well as a high PCE of 10% and an extremely small performance deviation within 0.14% were achieved. This study represents a method for realizing efficient and reproducible planar heterojunction (PHJ) PeSCs through morphology control, taking a major step forward in the low-cost and rapid production of PeSCs by solving one of the biggest problems of PHJ perovskite photovoltaic technology through a facile method.
Allergic rhinitis (AR) and diabetes mellitus (DM) share a common cause in inflammation; however, potential relationships between them are not clear. Therefore, we aimed to explore the associations ...between AR and DM. In this cross-sectional study, data were extracted from the Korean National Health and Nutrition Examination Survey 2007-2018 and weighted based on sociodemographic characters. AR and DM were defined by diagnoses thereof. Since self-reporting was not perfect, in order to complement the validity, we additionally performed sensitivity analysis by defining DM according to HbA1c and medication history. After excluding invalid data, the number of final participants was 29,246 (mean age, 54.95 ± 14.27 years). We calculated the odds ratio (OR) of newly self-reported DM among AR patients without DM history by multivariable logistic regression adjusted for potential confounders. A reverse association was also assessed. Patients with AR showed lower ORs for DM than those without AR (OR, 95% CI: men, 0.28, 0.19-0.42; women, 0.33, 0.24-0.46). Similarly, DM patients showed lower ORs for AR than patients without DM (men, 0.41, 0.31-0.56; women, 0.34, 0.25-0.46). The same results were obtained in sensitivity analysis defining DM according to HbA1c levels or DM treatment and in stratification analysis for age, residency, comorbidity, BMI, and menopause. In conclusion, we discovered that AR and DM show mutual inverse associations, regardless of sex, in individuals aged 30 years and older.
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•PIPL-H was developed to protect Li metal in batteries using aqueous electrolytes.•Facile fabrication of PIPL-H enabled uniform coating and high reproducibility.•Pre-impregnated ...high-concentration solution showed enhanced hydrophobicity.•PIPL-H effectively enhanced electrochemical performance during long-term cycling.
Aqueous electrolytes have been considered as alternatives for solving thermal safety issues of batteries caused by the high flammability of non-aqueous electrolytes. However, the use of low-potential anodes for high energy density batteries using aqueous electrolytes is limited by the narrow electrochemical stability window of water (1.23 V). Therefore, an artificial protective layer is required to compensate for the potential difference between the electrolyte and anode: however, using selectively conducting Li ions while suppressing water penetration during cycling tests in batteries is a key problem that has not yet been solved. In this study, a pre-impregnated protective layer using a Li ion conductive high concentration solution in a hydrophobic polymer framework (PIPL-H) was developed for the reversible use of Li metal in batteries using aqueous electrolyte. PIPL-H minimizes hydrogen evolution reactions by preventing direct contact between the water molecules and the Li metal. PIPL-H enabled a Li symmetric cell without increasing polarization for 1000 h, as well as a full cell using LiMn2O4 with 88.2 % capacity retention for up to 60 cycles. These results provide a new perspective into protective layers that enable stable operation without being constrained by the limited cathodic stability of aqueous electrolytes.
The insecticidal toxicities of five essential oils against Pochazia shantungensis adults and nymphs, newly recorded pests, were evaluated. The LC
values of Thymus vulgaris, Ruta graveolens, Citrus ...aurantium, Leptospermum petersonii and Achillea millefolium oils were recorded as 57.48, 84.44, 92.58, 113.26 and 125.78 mg/L, respectively, against P. shantungensis nymphs using the leaf dipping bioassay, and 75.80, 109.86, 113.26, 145.06 and 153.74 mg/L, respectively, against P. shantungensis adults using the spray bioassay method. Regarding volatile components identified in T. vulgaris oil, the LC
values of carvacrol and thymol using the leaf dipping bioassay against P. shantungensis nymphs were 56.74 and 28.52 mg/L, respectively. The insecticidal action of T. vulgaris oil against P. shantungensis could be attributed to carvacrol and thymol. Based on the structure-toxicity relationship between thymol analogs and insecticidal toxicities against P. shantungensis nymphs similar to the LC
values against P. shantungensis adults, the LC
values of thymol, carvacrol, citral, 2-isopropylphenol, 3-isopropylphenol, and 4-isopropylphenol were 28.52, 56.74 and 89.12, 71.41, 82.49, and 111.28 mg/L, respectively. These results indicate that the insecticidal mode of action of thymol analogs may be largely attributed to the methyl functional group. Thymol analogues have promising potential as first-choice insecticides against P. shantungensis adults and nymphs.
The 3D8 single chain variable fragment (scFv) is a mini-antibody that causes unusual sequence-independent nuclease activity against all types of nucleic acids. We used recombinant lentiviruses to ...generate transgenic chickens expressing the 3D8 scFv gene under the control of the chicken β-actin promoter. From 420 injected embryos, 200 chicks (G0) hatched and were screened for the 3D8 scFv using PCR, and 15 chicks were identified as transgenic birds expressing the transgene in their semen. The G0 founder birds were mated with wild-type hens to produce seven transgenic chicks (G1). 3D8 scFv expression in the chicken embryonic fibroblasts (CEFs) was verified by RT-PCR and Western blot analysis. Immunofluorescence staining for 3D8 scFv in the CEFs revealed that the 3D8 scFv protein was primarily cytosolic. To identify 3D8 scFv anti-viral activity, wild-type and two transgenic CEF lines were infected with H9N2 avian influenza virus (AIV). We selected one line of transgenic chickens that exhibited the lowest number of plaque-forming units to be challenged with H9N2 virus. The challenge experiment revealed that contact exposed transgenic chickens expressing 3D8 scFv exhibited suppressed viral shedding. This results suggest that the transgenic chickens developed in this study could be useful for controlling potential within-flock AIV transmission.
•Molecular weight reduction observed during PTB7 synthesis in a flow reactor.•Flow-induced chain scission of PTB7 under typical stille polycondensation conditions.•Flow degradation due to both ...mechanochemical and thermal phenomena.•Flow degradation is likely to be a competing side reaction in the flow polymerization.
The conjugated polymer PTB7 was found to undergo flow-induced chain scission under conditions typically employed in the flow synthesis of conjugated polymers, supporting that polymer degradation is a key side reaction that can influence the molecular weight of conjugated polymers synthesized in flow. Flow synthesis is becoming an increasing important method for the rapid and reproducible synthesis of conjugated polymers with optimal molecular weight. Increasing the length of time the polymerization solution remains in the flow system (the residence time), initially leads to an increase in molecular weight, but declines are observed at longer residence times. Our results support that conjugated polymers undergo mechanochemical chain scission in flow and that reactor temperature, polymer molecular weight, and polymer concentration are important factors that influence the extent of degradation. These results should aid in the future optimization of conjugated polymer syntheses in flow.
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