Switchable materials have developed greatly, because of their potential applications in many fields, such as data storage and dielectric devices, while the “ON”/“OFF” of the dielectric effect in ...polycrystalline materials to achieve high contrast is still a great challenge, which gradually become one of the research hotspots in the materials science and electronics. Herein, we report a prominent dielectric switch of (TMCM)
2
Hg
2
Cl
6
(
1
, TMCM = trimethylchloromethyl ammonium), with a high phase transition temperature (Tc) of 405.8 K and an extremely high contrast of ca. 14. Such a breakthrough is elucidated from the highly disordered TMCM and the severely deformed of Hg
2
Cl
6
in high temperature phase. By understanding the properties of superior dielectric, a feasible switch mechanism can be constructed to inject new vitality into the field of molecular medium switch.
Dear Editor, Patient-derived organoids (PDOs) closely recapitulate human colorectal cancer biology and have recently emerged as preclinical models for personalized therapy design.1 However, PDOs ...cultured in Matrigel (PDOsMatrigel) failed to predict outcome for treatment with the first-line FO chemotherapeutic regimen (5-fluorouracil plus oxaliplatin) for metastatic colorectal cancer (mCRC) patients.2 In this study, we establish in vitro culture conditions of mCRC-PDOs in a hydroxypropyl cellulose allyl conjugated with collagen (HA-Coll sponge),3 and utilized this system to examine the drug sensitivity of FO regimen (Figure 1A). Mechanical tension on a cell from its environment control gene expression to modulate tissue-specific differentiation8 and stiff environment could increase the transcription of lamin-A to alter nuclear rheology, thereby promoting cell differentiation.9 To figure out if lamin-A was involved in keeping the epithelial state in PDOsSponge, the expression level of lamin-A in nuclear proteins was examined by western blotting. Figure 4F and Figure S4F showed that the expression of lamin-A was dramatically decreased in PDOsMatrigel, but not in PDOsSponge, which was consistent with the previous studies that the matrix stiffness of Sponge3 is at the similar level to that of intestinal epithelial cells.10 Next we added retinoic acid (RA) to inhibit the expression level of lamin-A in PDOsSponge (Figure 4F, Figure S4F),9 and thereby enhance the percentage of CSCs in PDOsSponge (Figure 4E, Figure S4E), consequently, the IC50 value of FO in PDOsSponge was dramatically increased by RA (Figure 4G, Figure S4G).
Based on the existing systematic reviews and meta-analyses, we conducted this umbrella review aiming at evaluating the quality of evidence, validity and biases of the relationship between vitamin C ...(VC) intake and incidence and outcomes of multiple cancers. We identified 22 cancer outcomes within 3,562 articles. VC consumption was associated with lower incidence of bladder cancer, breast cancer, cervical tumors, endometrial cancer, esophageal cancer, gastric cancer, glioma, lung cancer, pancreatic cancer, prostate cancer, renal cell cancer, and total cancer occurrence. VC intake was also related to decreased risk of breast cancer prognosis (recurrence, cancer-specific mortality, and all-cause mortality).
A novel zigzag chain organic-inorganic hybrid compound of the general formula R2MI5, n-C3H7NH32SbI5 (1), was successfully synthesized, in which the n-propylammonium cations were located in the free ...cavities between the one-dimensional zigzag chains. Systematic characterization was performed to investigate the phase transition of 1. A pair of sharp peaks at 211.8 K (heating) and 203.7 K (cooling) with a hysteresis 8.1 K were observed in the differential scanning calorimetry (DSC) curve, indicating the first-order phase transition behavior of 1. The temperature dependence dielectric measurement demonstrated a step-like change at around 211.8 K, which makes 1 a potential switchable dielectric material. Frequency dependence measurement revealed that the frequency exerts a weak influence on the dielectric permittivity. Further structural analysis shows that both anionic and cationic moieties contribute to the phase transition, accompanied by weak hydrogen bond interactions between cations and the SbI5n(2-) chains.
The photochemical reactivity of humic substances plays a critical role in the global carbon cycle, and influences the toxicity, mobility, and bioavailability of contaminants by altering their ...molecular structure and the mineralization of organic carbon to CO
2
. Here, we examined the simulated irradiation process of Chinese standard fulvic acid (FA) and humic acid (HA) by using excitation-emission matrix fluorescence combined with fluorescence regional integration (FRI), parallel factor (PARAFAC) analysis, and kinetic models. Humic-like and fulvic-like materials were the main materials (constituting more than 90%) of both FA and HA, according to the FRI analysis. Four components were identified by the PARAFAC analysis: fulvic-like components composed of both carboxylic-like and phenolic-like chromophores (C1), terrestrial humic-like components primarily composed of carboxylic-like chromophores (C2), microbial humic-like overwhelming composed of phenolic-like fluorophores (C3), and protein-like components (C4). After irradiation for 72 h, the maximum fluorescence intensity (
F
max
) of C1 and C2 of FA was reduced to 36.01–58.34%, while the
F
max
of C3 of both FA and HA also decreased to 0–9.63%. By contrast, for HA, the
F
max
of its C1 and C2 increased to 236.18–294.77% when irradiated for 72 h due to greater aromaticity and photorefractive tendencies. The first-order kinetic model (
R
2
= 0.908–0.990) fitted better than zero-order kinetic model (
R
2
= 0–0.754) for the C1, C2, and C3, of both FA and HA, during their photochemical reactivity. The photodegradation rate constant (
k
1
) of C1 had values (0.105 for FA; 0.154 for HA) that surpassed those of C2 (0.059 for FA, 0.079 for HA) and C3 (0.079 for both FA and HA) based on the first-order kinetic model. The half-life times of C1, C2, and C3 ranged from 6.61–11.77 h to 4.50–8.81 h for FA and HA, respectively. Combining an excitation-emission matrix with FRI and PARAFAC analyses is a powerful approach for elucidating changes to humic substances during their irradiation, which is helpful for predicting the environmental toxicity of contaminants in natural ecosystems.
► A
Rhodococcus strain could use pyridine as the sole carbon and nitrogen source. ► It could degrade pyridine at low concentrations of phenol and Cr (VI). ► Phenol at low concentration could ...stimulate the strain to degrade pyridine. ► It is the first
Rhodococcus strain reported to have these abilities.
A
Rhodococcus strain, Chr-9, which has the ability to degrade pyridine and phenol and reduce chromium (VI) (Cr (VI)) was isolated. The strain could grow with pyridine as the sole carbon and nitrogen source, and its pyridine-degradation capability was enhanced by 100
mg
l
−1 phenol; however, the degradation of pyridine was inhibited when the phenol concentration was greater than 400
mg
l
−1. The hydroxylation of pyridine suggested that the stimulation and inhibition of phenol to the pyridine degradation may be attributed to competition of phenol and pyridine for the hydroxylase gene. Strain Chr-9 was also able to reduce Cr (VI) when glucose and LB was used as the carbon source; however, the Cr (VI) reduction did not occur when pyridine was the sole carbon and energy source. In addition, strain Chr-9 could reduce Cr (VI) and simultaneously degrade pyridine in the presence of glucose. To the best of our knowledge, strain Chr-9 is the first
Rhodococcus strain reported to degrade pyridine in the presence of Cr (VI), and the first strain with the pyridine degradation being stimulated by low concentrations of phenol.
An HPLC-DAD method for the analysis of 10 nucleotides and related compounds (NRCs) in Litopenaeus vannamei was established. Hyperchloric acid was used to precipitate proteins. Samples were separated ...on an ODS-3 C18 (4.6 mm × 250 mm, 5 μm) column with 0.02 M phosphate buffer (pH = 5.8) as mobile phase A. All 10 NRCs were completely separated within 25 min. Good linearity was seen in the concentration range from 0 to 500 μmol/L with correlation coefficients between 0.9996 and 0.9999. Limit of detection was between 0.02 and 0.10 μg/mL and spike recoveries were between 72.5% and 110%. This method is facile, reliable, and accurate for the analysis of 10 NRCs in shrimp muscle samples. Using this method, the changes of NRCs in L. vannamei were studied during chilled storage at 4 °C. Important correlations between the changes of NRCs and the flavor/freshness of L. vannamei were proposed.
•An HPLC-DAD method for analyzing 10 nucleotides and related compounds in L. vannamei.•Column, pH and mobile phase were optimized and method was validated.•Changes of NRCs in L. vannamei when stored at 4 °C were related to its flavor/freshness.
Spidroin-1 is one of the major ampullate silk proteins produced by spiders for use in the construction of the frame and radii of orb webs, and as a dragline to escape from predators. Only partial ...sequences of spidroin-1 produced by Nephila clavipes have been reported up to now, and there is no information on post-translational modifications (PTMs). A gel-based mass spectrometry strategy with ETD and CID fragmentation methods were used to sequence and determine the presence/location of any PTMs on the spidroin-1. Sequence coverage of 98.06%, 95.05%, and 98.37% were obtained for N. clavipes, Nephila edulis and for Nephila madagascariensis, respectively. Phosphorylation was the major PTM observed with 8 phosphorylation sites considered reliable on spidroin-1 produced by N. clavipes, 4 in N. madagascariensis and 2 for N. edulis. Dityrosine and 3,4-dihydroxyphenylalanine (formed by oxidation of the spidroin-1) were observed, although the mechanism by which they are formed (i.e. exposure to UV radiation or to peroxidases in the major ampullate silk gland) is uncertain. Herein we present structural information on the spidroin-1 produced by three different Nephila species; these findings may be valuable for understanding the physicochemical properties of the silk proteins and moreover, future designs of recombinantly produced spider silk proteins.
Biotechnological significance
The present investigation shows for the first time spidroin structure and post-translational modifications observed on the major ampullate silk spidroin-1. The many site specific phosphorylations (localized within the structural motifs) along with the probably photoinduction of hydroxylations may be relevant for scientists in material science, biology, biochemistry and environmental scientists. Up to now all the mechanical properties of the spidroin have been characterized without any consideration about the existence of PTMs in the sequence of spidroins. Thus, these findings for major ampullate silk spidroin-1 from Nephila spiders provide the basis for mechanical–elastic property studies of silk for biotechnological and biomedical potential applications. This article is part of a Special Issue entitled: Proteomics of non-model organisms.
Display omitted
•We used a gel-based mass spectrometry strategy (ETD and CID fragmentation methods).•We show for the first time PTMs on the major ampullate silk spidroin-1.•Phosphorylation was the major PTM observed.•Dityrosine and 3,4-dihydroxyphenylalanine were also observed.•Our findings may be valuable for understanding the silk physicochemical properties.
Electroconvulsive therapy (ECT) is an effective treatment for depression, but the mechanism of ECT for depression is still unclear. Recently, neuroimaging studies have reported that the prefrontal ...cortex, hippocampus, angular gyrus, insular and other brain regions are involved in the mechanism of ECT for depression, and these regions are highly overlapped with the location of brain hubs. Here, we try to explore the effects of ECT on the functional connectivity of brain hubs in depression patients. In current study, depression patients were assessed at three time points: prior to ECT, at the completion of ECT and about 1 month after the completion of ECT. At each time point, resting-state functional magnetic resonance imaging, assessment of clinical symptoms and cognition function were performed respectively, which was compared with 20 normal controls. Functional connectivity strength (FCS) was used to identify brain hubs. The results showed that FCS of left angular gyrus in depression patients significantly increased after ECT, accompanied by improved mood. The changed FCS in depression patients recovered obviously at 1 month after the completion of ECT. It suggested that ECT could modulate functional connectivity of left angular gyrus in depression patients.
PDF
