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Biochemistry and Biophysics Reports Jul 2024Single-molecule intramolecular dynamics were successfully measured for three variants of SARS-CoV-2 spike protein, alpha: B.1.1.7, delta: B.1.617, and omicron:...
Single-molecule intramolecular dynamics were successfully measured for three variants of SARS-CoV-2 spike protein, alpha: B.1.1.7, delta: B.1.617, and omicron: B.1.1.529, with a time resolution of 100 μs using X-rays. The results were then compared with respect to the magnitude and directions of motions for the three variants. The largest 3-D intramolecular movement was observed for the omicron variant irrespective of ACE2 receptor binding. A more detailed analysis of the intramolecular motions revealed that the distribution state of intramolecular motion for the three variants was completely different with and without ACE2 receptor binding. The molecular dynamics for the trimeric spike protein of the omicron variant increased when ACE2 binding occurred. At that time, the diffusion constant increased from 71.0 [mrad/ms] to 91.1 [mrad/ms].
PubMed: 38903159
DOI: 10.1016/j.bbrep.2024.101712 -
Dental Materials : Official Publication... Jun 2024Commercially available resin cements consist of various filler sizes, filler content and monomers, and it is unclear which of these factors have the greatest effect on...
STATEMENT OF PROBLEM
Commercially available resin cements consist of various filler sizes, filler content and monomers, and it is unclear which of these factors have the greatest effect on the color stability of laminate veneers.
OBJECTIVES
To evaluate the color stability of lithium disilicate-reinforced laminate veneers inserted with three commercial resin cements with various filler sizes/contents and monomers upon accelerated aging.
METHODS
Veneers were fabricated and cemented on resin abutments using three commercially available resin cements comprised of two different monomers and varying filler sizes/contents: 1) triethylene glycol dimethacrylate, TEGDMA (RelyX™ Veneer = 0.6 µm/66 %, Calibra® Esthetic Light Cure =1.2 µm/65 %); and 2) urethane dimethacrylate, UDMA (Variolink Esthetic LC = 0.1 µm/38 %). A total of 60 specimens were fabricated (n = 20 for each cement). The relative number of particles (N) and relative surface area (A) were calculated for each filler size/content. Color coordinates (L*, a*, b*) were measured, and color change (ΔE) was calculated after cementation and following aging at 150, 300, 450, and 600 h using xenon light. Differences in color coordinates and color change were determined using repeated measures ANOVA followed by Tukey's post hoc test (α = .05). A post-hoc power analysis was performed to confirm reliability of the results.
RESULTS
Based on a post-hoc power analysis of a repeated measures ANOVA with two between-factors and 1 within-factor, we had 89 % power to detect a difference of effect by cement type, 10 % power to detect a difference by shade, and 100 % power to detect a difference of effect by aging. The UDMA-based cement (0.1 µm/38 %) was least affected by aging, despite having the largest number of particles (N = 1010) and largest particle surface area (A = 7.02). The TEGDMA-based cements exhibited a significant color change, with 0.6 µm/66 % (A = 2.03, N = 8.12) producing a larger ΔE than 1.2 µm/65 % (A = 1.00, N = 1.00).
CONCLUSIONS
Among the commercial cements tested, UDMA-based resin (0.1 µm/38 %) provided better color stability than TEGDMA-based resin cements. The color change after aging was affected by the relative surface area and relative number of particles for the TEGDMA-based resin cement (0.6 µm/66 % and 1.2 µm/65 %), with a larger surface area and a higher relative number of particles, accelerated color change with aging. The present study demonstrates a novel approach to determine color stability for any resin cement with particulate filler.
CLINICAL IMPLICATIONS
The dental practitioner should be selective in choosing a commercial light cure cementation product for laminate veneers, as UDMA containing resin cement is more resistant to color changes over time than TEGDMA, regardless of the filler size/content.
PubMed: 38902146
DOI: 10.1016/j.dental.2024.06.001 -
Environmental Research Jun 2024The fruit Pyrus communis, owing to its presence of phenolics and flavonoids, was chosen for its nanoparticle's reducing and stabilizing properties. Furthermore, the zinc...
The fruit Pyrus communis, owing to its presence of phenolics and flavonoids, was chosen for its nanoparticle's reducing and stabilizing properties. Furthermore, the zinc metal may be nano-absorbed by the human body. As a result, the study involves synthesizing zinc oxide nanoparticles (ZnO NPs) from P. communis fruit extract using the green method. The synthesized nanoparticle was examined with a UV-visible spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS). When absorption studies were performed with a UV-visible spectrophotometer, the nanoparticle exhibited a blue shift. The FTIR spectrum revealed the molecular groups present in both the fruit extract and metal. In the SEM analysis, the ZnO NPs appeared as spherical particles, agglomerated together, and of nano-size. The larger size of the ZnO NPs in DLS can be attributed to their ability to absorb water. After characterization, nanoparticles were tested for anti-diabetic (α-amylase and yeast glucose uptake activity) and anti-microbial properties. The α-amylase inhibition percentage was 46.46 ± 0.15% for 100 μg/mL, which was comparable to the acarbose inhibition percentage of 50.58 ± 0.67% at the same concentration. The yeast glucose uptake activity was 64.24 ± 0.80% at 20 mM glucose concentration, which was comparable to the standard of 78.03 ± 0.80. The nanoparticle was more effective against Gram-negative bacteria Shigella sp. and Salmonella typhi than against Gram-positive bacteria Bacillus cereus and Streptococcus pneumoniae.
PubMed: 38901812
DOI: 10.1016/j.envres.2024.119450 -
Free Radical Biology & Medicine Jun 2024Repeated sevoflurane exposure in neonatal mice triggers neuroinflammation with detrimental effects on cognitive function. Yet, the mechanism of the sevoflurane-induced...
Repeated sevoflurane exposure in neonatal mice triggers neuroinflammation with detrimental effects on cognitive function. Yet, the mechanism of the sevoflurane-induced cytokine response is largely unknown. In this study, we reveal that 3-MA, an autophagy inhibitor, attenuated the sevoflurane-induced neuroinflammation and cognitive dysfunction, including the decreased freezing time and fewer platform crossings, in the neonate mice. 3-Methyladenine (3-MA) suppressed sevoflurane-induced expression of interleukin-6 and tumor necrosis factor-alpha in vitro. Moreover, sevoflurane activates IRF3, facilitating cytokine transcription in an AKT3-dependent manner. Mechanistically, sevoflurane-induced autophagic degradation of dehydrocholesterol-reductase-7 (DHCR7) resulted in accumulations of its substrate 7-dehydrocholesterol (7-DHC), mimicking the effect of sevoflurane on AKT3 activation and IRF3-driven cytokine expression. 3-MA significantly reversed sevoflurane-induced DHCR7 degradation, AKT phosphorylation, IRF3 activation, and the accumulation of 7-DHC in the hippocampal CA1 region. These findings pave the way for additional investigations aimed at developing novel strategies to mitigate postoperative cognitive impairment in pediatric patients.
PubMed: 38901498
DOI: 10.1016/j.freeradbiomed.2024.06.012 -
Journal of Colloid and Interface Science Jun 2024Catalytic oxidation of carbon monoxide (CO) by Cu/AlO has garnered increasing interest in recent years due to its promising application prospects. Numerous...
Catalytic oxidation of carbon monoxide (CO) by Cu/AlO has garnered increasing interest in recent years due to its promising application prospects. Numerous investigations conducted on the Cu/AlO system, but its catalytic performance for CO oxidation is still not as promising as that of precious metal catalysts. Increasing the loading amount of the active Cu on AlO surface is a feasible method for improving its activity. However, with the increase of Cu loading, the agglomeration and enlargement of Cu particles is inevitable, which reduces the active Cu amount. Therefore, the utilization rate of Cu atoms is not high and the catalytic performance often can not further rise. Enhancing active Cu loading amount as high as possible is a prerequisite to further enlarge the activity of Cu/AlO catalyst. Herein, self-synthesized AlO nanofibers (AlO-nf) with high specific surface area and abundant penta-coordinated aluminum (Al) are used as the support to maximize the Cu loading amount by chemical vapor deposition (CVD). And commercially available α-AlO is used for comparative experiment. The high specific surface area could make Cu high dispersion on AlO, even at 20 wt% Cu loads, which is beneficial to high concentration load of active Cu. The catalytic activity of Cu/AlO-nf-CVD gradually increases with the increase of Cu loading from 2 wt% to 20 wt%, exhibiting a clear linear correlation with the surface content of Cu on the catalyst. Meanwhile, this result confirms that Cu plays a crucial role in CO oxidation of Cu/AlO. However, commercial α-AlO reaches its highest activity when the Cu load is 5%, and then its activity begins to decrease due to the agglomeration of particles. Moreover, Cu/AlO-nf-CVD also exhibits remarkable thermal stability for CO oxidation. This work highlights a new strategy to synthesis of high Cu loading amount, high activity and thermostable Cu/AlO catalyst for low-temperature oxidation of CO.
PubMed: 38901357
DOI: 10.1016/j.jcis.2024.06.130 -
The Journal of Organic Chemistry Jun 2024We report the first example of copper-catalyzed α-alkylation of acetamides with alcohols via a borrowing hydrogen strategy. Catalyzed by the -generated copper...
We report the first example of copper-catalyzed α-alkylation of acetamides with alcohols via a borrowing hydrogen strategy. Catalyzed by the -generated copper particles, acetamides and various substituted benzyl or alkyl alcohols were transformed into functionalized amides in good yields with excellent selectivity. Compared with previous work, this process is simple using commercially available Cu(OAc) as a precatalyst, without an additional ligand or a metal complex, and easier. Mechanistic studies revealed that aldehyde and α,β-unsaturated amides were the intermediates of this reaction and also disclosed the role of copper in alcohol dehydrogenation and C═C bond hydrogenation.
PubMed: 38900965
DOI: 10.1021/acs.joc.4c00404 -
Journal of Otolaryngology - Head & Neck... 2024Neck dissections (ND) are a routine procedure in head and neck oncology. Given the postoperative functional impact that some patients experience, it is imperative to...
BACKGROUND
Neck dissections (ND) are a routine procedure in head and neck oncology. Given the postoperative functional impact that some patients experience, it is imperative to identify and track quality of life (QoL) symptomatology to tailor each patient's therapeutic needs. To date, there is no validated French-Canadian questionnaire for this patient-population. We therefore sought to translate and validate the Neck Dissection Impairment Index (NDII) in Canadian French.
METHODS
A 3-phased approach was used. Phase 1: The NDII was translated from English to Canadian French using a "forward and backward" translational technique following international guidelines. Phase 2: A cognitive debriefing session was held with 10 Canadian French-speaking otolaryngology patients to evaluate understandability and acceptability. Phase 3: The final version was administered prospectively to 30 patients with prior history of ND and 30 control patients. These patients were asked to complete the questionnaire 2 weeks after their first response. Test-retest reliability was calculated with Spearman's correlation. Internal consistency was elicited using Cronbach's alpha.
RESULTS
NDII was successfully translated and validated to Canadian French. Cronbach's alpha revealed high internal consistency (0.92, lower 95% confidence limit 0.89). The correlation for test-retest validity were strong or very strong (0.61-0.91).
CONCLUSION
NDII is an internationally recognized QoL tool for the identification of ND-related impairments. This validated Canadian French version will allow clinicians to adequately assess the surgery-related QoL effect of neck surgery in the French-speaking population, while allowing French institutions to conduct and/or participate in multisite clinical trials requiring the NDII as an outcome measure.
Topics: Humans; Quality of Life; Neck Dissection; Female; Male; Middle Aged; Canada; Surveys and Questionnaires; Translations; Head and Neck Neoplasms; Reproducibility of Results; Aged; Adult; Prospective Studies; Surgical Oncology
PubMed: 38899627
DOI: 10.1177/19160216241263852 -
Journal of Cellular and Molecular... Jun 2024Hypoxia poses a significant challenge to the effectiveness of radiotherapy in head and neck squamous cell carcinoma (HNSCC) patients, and it is imperative to discover...
Hypoxia poses a significant challenge to the effectiveness of radiotherapy in head and neck squamous cell carcinoma (HNSCC) patients, and it is imperative to discover novel approaches to overcome this. In this study, we investigated the underlying mechanisms contributing to x-ray radioresistance in HPV-negative HNSCC cells under mild hypoxic conditions (1% oxygen) and explored the potential for autophagy modulation as a promising therapeutic strategy. Our findings show that HNSCC cells exposed to mild hypoxic conditions exhibit increased radioresistance, which is largely mediated by the hypoxia-inducible factor (HIF) pathway. We demonstrate that siRNA knockdown of HIF-1α and HIF-1β leads to increased radiosensitivity in HNSCC cells under hypoxia. Hypoxia-induced radioresistance was not attributed to differences in DNA double strand break repair kinetics, as these remain largely unchanged under normoxic and hypoxic conditions. Rather, we identify autophagy as a critical protective mechanism in HNSCC cells following irradiation under mild hypoxia conditions. Targeting key autophagy genes, such as BECLIN1 and BNIP3/3L, using siRNA sensitizes these cells to irradiation. Whilst autophagy's role in hypoxic radioresistance remains controversial, this study highlights the importance of autophagy modulation as a potential therapeutic approach to enhance the effectiveness of radiotherapy in HNSCC.
Topics: Humans; Autophagy; Radiation Tolerance; Cell Line, Tumor; Squamous Cell Carcinoma of Head and Neck; Cell Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Beclin-1; Head and Neck Neoplasms; Membrane Proteins; DNA Repair; RNA, Small Interfering; Proto-Oncogene Proteins; X-Rays; DNA Breaks, Double-Stranded; Tumor Suppressor Proteins
PubMed: 38899556
DOI: 10.1111/jcmm.18482 -
Chinese Neurosurgical Journal Jun 2024Glioblastoma are highly malignant type of primary brain tumors. Treatment for glioblastoma multiforme (GBM) generally involves surgery combined with chemotherapy and...
BACKGROUND
Glioblastoma are highly malignant type of primary brain tumors. Treatment for glioblastoma multiforme (GBM) generally involves surgery combined with chemotherapy and radiotherapy. However, the development of tumoral chemo- and radioresistance induces complexities in clinical practice. Multiple signaling pathways are known to be involved in radiation-induced cell survival. However, the role of alpha-thalassemia X-linked mutant retardation syndrome (ATRX), a chromatin remodeling protein, in GBM radioresistance remains unclear.
METHODS
In the present study, the ATRX mutation rate in patients with glioma was obtained from The Cancer Genome Atlas, while its expression analyzed using bioinformatics. Datasets were also obtained from the Gene Expression Omnibus, and ATRX expression levels following irradiation of GBM were determined. The effects of ATRX on radiosensitivity were investigated using a knockdown assays.
RESULTS
The present study demonstrated that the ATRX mutation rate in patients with GBM was significantly lower than that in patients with low-grade glioma, and that patients harboring an ATRX mutation exhibited a prolonged survival, compared with to those harboring the wild-type gene. Single-cell RNA sequencing demonstrated that ATRX counts increased 2 days after irradiation, with ATRX expression levels also increasing in U-251MG radioresistant cells. Moreover, the results of in vitro irradiation assays revealed that ATRX expression was increased in U-251MG cells, while ATRX knockdown was associated with increased levels of radiosensitivity.
CONCLUSIONS
High ATRX expression levels in primary GBM may contribute to high levels of radioresistance. Thus ATRX is a potential target for overcoming the radioresistance in GBM.
PubMed: 38898533
DOI: 10.1186/s41016-024-00371-6 -
Sensors (Basel, Switzerland) Jun 2024Radon, a radioactive inert gas that comes from the decay of naturally occurring radioactive species, poses a substantial health risk due to its involvement in lung...
Radon, a radioactive inert gas that comes from the decay of naturally occurring radioactive species, poses a substantial health risk due to its involvement in lung cancer carcinogenesis. This work proposes a metrological approach for determining radon exhalation rates from diverse building materials. This methodology employs an electrostatic collection chamber for alpha spectrometry of radon isotopic decay products. Experimental evaluations were conducted particularly focusing on volcanic gray tuff from Sant'Agata de' Goti (Campania region, Italy), a material commonly utilized in construction, to assess radon exhalation rates. The study aligns with Legislative Decree 101/2020, a transposition of European Directive 59/2013/Euratom, highlighting the need to identify materials with a high risk of radon exhalation. Moreover, this work supports the goals of the Italian National Radon Action Plan related to the aforementioned decree, aiming to develop methodologies for estimating radon exhalation rates from building materials and improving radioprotection practices.
PubMed: 38894424
DOI: 10.3390/s24113633