Chain‐growth polymerization of aromatic building blocks (termed catalyst‐transfer polycondensation or CTP) has emerged as a powerful method for the controlled synthesis of conjugated polymers. CTP ...affords semiconducting materials with predictable molecular weights, relatively narrow molar mass distributions and tailored backbone compositions (e.g. blocks, gradients, stars). Homogeneous catalysis utilizing transition metals has played a critical role in the rise of this field and this Minireview is designed to highlight some of the catalysts employed for these polycondensations. Some descriptions of the metal and ancillary ligands are included, along with which catalysts have been used for different aromatic monomers. Cross‐coupling strategies are discussed briefly for ease of use. Finally, some potential future directions are described for further evolution of this exciting area.
The controlled synthesis of π‐conjugated polymers was discovered nearly 15 years ago. Since that time, the importance of metal catalysts and how they play a role in controlling the polymerization process has become an active area of research. This Minireview highlights some of the general features of metal complexes used in catalyst‐transfer polycondensation (CTP), the typical monomers that can be polymerized and, describes a few potential avenues for future exploration.
A commercially available palladium N‐heterocyclic carbene (Pd‐NHC) precatalyst is used to initiate chain‐growth polymerization of 2‐bromo‐3‐hexyl‐5‐trimethylstannylthiophene. The molecular weight of ...the resultant poly(3‐hexylthiophene) can be modulated (7 to 73 kDa, Đ = 1.14 to 1.53) by varying the catalyst concentration. Mass spectrometry data confirm control over the polymer end groups and 1H NMR spectroscopy reveals that the palladium catalyst is capable of “ring‐walking”. A linear relationship between Mn and monomer conversion is observed. Atomic force microscopy and X‐ray scattering verify the regioregular nature of the resultant polythiophene.
Stille catalyst‐transfer polycondensation of a thiophene monomer using a palladium N‐heterocyclic carbene catalyst is described. 1H NMR spectroscopy of the material indicates that the catalyst can “ring‐walk”, the polymer backbone is highly regioregular, and the molecular weight can be controlled. Excellent end‐group fidelity is observed using this polymerization process.
Antimicrobial peptides (AMPs) are short and positively charged peptides with broad-spectrum antimicrobial activities. AMPs have been investigated as potential antibiotic alternatives to improve ...growth performance and prevent pathogen infection in the poultry industry. The antimicrobial peptide tilapia piscidin 4 (TP4) was derived from Oreochromis niloticus, possesses antimicrobial activities and immunomodulatory properties, promotes intestinal health, and protects against pathogen infection. The codon-optimized sequence of TP4 was introduced into the pPICZalphaA vector and transformed into Pichia pastoris. Large-scale expression was induced following culture with methanol in a 500-liter fermenter. Freeze drying of fermented rTP4 broth and then rTP4 evaluation as a feed additive for Gallus gallus domesticus were performed. The in vitro antimicrobial activity of recombinant TP4 (rTP4) against gram-positive and gram-negative pathogens was evaluated. Evaluation of the effect of temperature on the antimicrobial activity of rTP4 showed its high stability at high temperatures. rTP4 significantly enhanced the phagocytic activity of macrophage cells, indicating that rTP4 has a remarkable ability to stimulate macrophages. rTP4 was used as a dietary supplement at 0.75, 1.5, 3.0, 6.0 and 12% in G. g. domesticus for five weeks, and growth performance, gut microbiota composition, and histology were assessed. The 3.0% rTP4 supplement group showed a significant increase in weight gain ratio and feed efficiency compared to those of the basal broiler diet group. Crude rTP4 was expressed by yeast to significantly promote growth efficiency and resistance against pathogens in G. g. domesticus, which could indicate its use as a suitable alternative to antibiotics as feed additives in the poultry industry.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
The Levelized Cost of Electricity (LCOE) is a widely used indicator to assess the electricity cost of wind energy. The probabilistic approach and Monte Carlo technique are commonly used to ...capture the uncertainty of input variables in the LCOE calculation at the country level. However, a simple assumption for the range value of capacity factor (CF), a main input variable in the LCOE calculation, is inappropriate for analyzing an individual wind project. To apply the probabilistic approach in the assessment of electricity cost for individual wind projects, the study develops a new approach for estimating the CF distribution for a specific project. We focus on simulating the CF distribution for a specific wind farm based on the historical CF values computed from historical wind speed at the site. In comparison to traditional approaches, the proposed method provides a reliable range of capacity factor values and reduces the uncertainty in estimating energy generation by half for four example projects. As a result, the generated LCOE distribution is relatively closer to the real value of the projects, enhancing more realistic decisions for both project developers and policymakers.
Platycodi radix is a widely used herbal medicine that contains numerous phytochemicals beneficial to health. The health and biological benefits of P. radix have been found across various diseases. ...The utilization of umbilical cord stromal stem cells, derived from Wharton's jelly of the human umbilical cord, has emerged as a promising approach for treating degenerative diseases. Nevertheless, growing evidence indicates that the function of stem cells declines with age, thereby limiting their regenerative capacity. The primary objective in this study is to investigate the beneficial effects of P. radix in senescent stem cells. We conducted experiments to showcase that diminished levels of Lamin B1 and Sox‐2, along with an elevation in p21, which serve as indicative markers for the senescent stem cells. Our findings revealed the loss of Lamin B1 and Sox‐2, coupled with an increase in p21, in umbilical cord stromal stem cells subjected to a low‐dose (0.1 μM) doxorubicin (Dox) stimulation. However, P. radix restored the Dox‐damage in the umbilical cord stromal stem cells. P. radix reversed the senescent conditions when the umbilical cord stromal stem cells exposed to Dox‐induced reactive oxygen species (ROS) and mitochondrial membrane potential are significantly changed. In Dox‐challenged aged umbilical cord stromal stem cells, P. radix reduced senescence, increased longevity, prevented mitochondrial dysfunction and ROS and protected against senescence‐associated apoptosis. This study suggests that P. radix might be as a therapeutic and rescue agent for the aging effect in stem cells. Inhibition of cell death, mitochondrial dysfunction and aging‐associated ROS with P. radix provides additional insights into the underlying molecular mechanisms.
This study examined the effects of a 12-week physical activity intervention on the motor skill proficiency and executive function of 22 boys (aged 9.08 ± 1.75 years) with autism spectrum disorder. In ...Phase I of the 12 weeks, 11 boys with autism spectrum disorder (Group A) received the intervention, whereas the other 11 boys with autism spectrum disorder (Group B) did not (true control, no intervention). The arrangement was reversed in Phase II, which lasted an additional 12 weeks. The Bruininks–Oseretsky Test of Motor Proficiency, Second Edition, and the Wisconsin Card Sorting Test were conducted three times for each participant (Group A, primary grouping: baseline (T1), post-assessment (T2), and follow-up assessment (T3); Group B, control grouping: T1−T2; intervention condition, T2−T3). The main findings were that both groups of children with autism spectrum disorder significantly exhibited improvements in motor skill proficiency (the total motor composite and two motor-area composites) and executive function (three indices of the Wisconsin Card Sorting Test) after 12 weeks of physical activity intervention. In addition, the effectiveness appeared to have been sustained for at least 12 weeks in Group A. The findings provide supporting evidence that physical activity interventions involving table tennis training may be a viable therapeutic option for treating children with autism spectrum disorder.
A low temperature ( < 150 deg C) fabrication method for preparation of TiO2 porous films with high efficiency in dye-sensitized solar cells (DSSCs) has been developed. The Ti(IV) tetraisopropoxide ...(TTIP) was added to the paste of TiO2 nanoparticles to interconnect the TiO2 particles. The electrochemical impedance spectroscopy (EIS) technique was employed to quantify the charge transport resistance at the TiO2/dye/electrolyte interface (Rct2) and electron lifetime in the TiO2 film (taue) under different molar ratios of TTIP/TiO2 and also at various TiO2 thicknesses. It was found that the Rct2 decreased as the molar ratio increased from 0.02 to 0.08, however, it increased at a molar ratio of 0.2 due to the reduction in surface area for dye adsorption. In addition, the characteristic frequency peak shifted to lower frequency at a molar ratio of 0.08, indicating the longer electron lifetime. As for the thickness effect, TiO2 film with a thickness around 17 mum achieved the best cell efficiency. EIS study also confirmed that, under illumination, the smallest Rct2 was associated with a TiO2 thickness of 17 mum, with the Rct2 increased as the thickness of TiO2 film increased. In the Bode plots, the characteristic frequency peaks shifted to higher frequency when the thickness of TiO2 increased from 17.2 to 48.2 mum, indicating the electron recombination increases as the thickness of the TiO2 electrode increases. Finally, to make better use of longer wavelength light, 30 wt% of larger TiO2 particle (300 nm) was mixed with P25 TiO2 as light scattering particles. It effectively increased the short-circuit current density and cell conversion efficiency from 7.44 to 8.80 mA cm-2 and 3.75 to 4.20%, respectively.
Hereditary transthyretin amyloid cardiomyopathy (hATTR-CM) is a progressive and fatal disease. Recent evidence indicates that bone scintigraphy may serve as a tool to monitor the effectiveness of ...hATTR-CM treatment. The objective of this study was to examine how eplontersen therapy influences the semiquantitative uptake of technetium-99m-pyrophosphate in individuals diagnosed with hATTR-CM.
We retrospectively analyzed a prospective cohort from the NEURO-TTRansform trial, including patients with hATTR-CM receiving eplontersen (45 mg/4 weeks). A control group comprised patients with hATTR-CM who had not received eplontersen, inotersen, tafamidis, or patisiran. Technetium-99m-pyrophosphate single-photon emission computed tomography/computed tomography was conducted at baseline and during follow-up. Thirteen patients with hATTR-CM were enrolled, with 6 receiving eplontersen and 7 serving as the control group. The median follow-up time was 544 days. The eplontersen group exhibited a significant decrease in volumetric heart and lung ratio (3.774 to 2.979,
=0.028), whereas the control group showed no significant change (4.079 to 3.915,
=0.237). Patients receiving eplontersen demonstrated a significantly greater reduction in volumetric heart and lung ratio compared with the control group (-20.7% versus -3.4%,
=0.007).
The volumetric heart and lung ratio used to quantify technetium-99m-pyrophosphate uptake showed a significant reduction subsequent to eplontersen treatment in individuals diagnosed with hATTR-CM. These findings suggest the potential efficacy of eplontersen in treating hATTR-CM and highlight the value of technetium-99m-pyrophosphate single-photon emission computed tomography/computed tomography as a tool for monitoring therapeutic effectiveness.
Purpose: This study assessed the associations of motor skill competence with physical activity and physical self-perception of adolescents with autism spectrum disorder (ASD).
Study design: ...Cross-sectional study.
Methods: A total of 63 male adolescents, aged 12-18 years, with ASD participated in the study. The Bruininks-Oseretsky Test of Motor Proficiency-Second Edition and the Chinese version of the Physical Self-Perception Profile were administered. Physical activity was assessed using a uniaxial accelerometer.
Results: The main findings were that (a) both moderate-to-vigorous physical activity and self-perceived physical condition were positively related to manual coordination (MC) and strength and agility (SA); (b) moderate-to-vigorous physical activity was the only predictor of MC and accounted for 14% of the variance; and (c) perceived physical condition explained 16% of the variance in SA, and moderate-to-vigorous physical activity and perceived physical condition together accounted for 26% of the SA.
Conclusion: Future interventions aimed at improving motor skill competence in adolescents with ASD should focus on improving the time spent on moderate-to-vigorous physical activity and developing a positive perceived physical condition.
Implications for rehabilitation
Less than half of the participants with ASD accumulated at least 60 min of daily moderate-to-vigorous physical activity.
Of the participants with ASD, only 19% had clinical levels of total motor impairments.
Activities that promote successful moderate-to-vigorous physical activity and support positive physical self-perception (i.e., physical condition) are most likely to develop motor skill competency in adolescents with ASD.
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