Gold nanoparticles (GNPs) have shown potential as dose enhancers for radiation therapy. Since damage to the genome affects the viability of a cell, it is generally assumed that GNPs have to localise ...within the cell nucleus. In practice, however, GNPs tend to localise in the cytoplasm yet still appear to have a dose enhancing effect on the cell. Whether this effect can be attributed to stress-induced biological mechanisms or to physical damage to extra-nuclear cellular targets is still unclear. There is however growing evidence to suggest that the cellular response to radiation can also be influenced by indirect processes induced when the nucleus is not directly targeted by radiation. The mitochondrion in particular may be an effective extra-nuclear radiation target given its many important functional roles in the cell. To more accurately predict the physical effect of radiation within different cell organelles, we measured the full chemical composition of a whole human lymphocytic JURKAT cell as well as two separate organelles; the cell nucleus and the mitochondrion. The experimental measurements found that all three biological materials had similar ionisation energies 70 eV, substantially lower than that of liquid water 78 eV. Monte Carlo simulations for 10-50 keV incident photons showed higher energy deposition and ionisation numbers in the cell and organelle materials compared to liquid water. Adding a 1% mass fraction of gold to each material increased the energy deposition by a factor of 1.8 when averaged over all incident photon energies. Simulations of a realistic compartmentalised cell show that the presence of gold in the cytosol increases the energy deposition in the mitochondrial volume more than within the nuclear volume. We find this is due to sub-micron delocalisation of energy by photoelectrons, making the mitochondria a potentially viable indirect radiation target for GNPs that localise to the cytosol.
It is challenging to reduce ground-level ozone (O3) pollution at a given locale, due in part to the contributions of both local and distant sources. We present direct evidence that the increasing ...regional effects have negated local control efforts for O3 pollution in Hong Kong over the past decade, by analyzing the daily maximum 8 h average O3 and O x (=O3+NO2) concentrations observed during the high O3 season (September–November) at Air Quality Monitoring Stations. The locally produced O x showed a statistically significant decreasing trend over 2002–2013 in Hong Kong. Analysis by an observation-based model confirms this decline in in situ O x production, which is attributable to a reduction in aromatic hydrocarbons. However, the regional background O x transported into Hong Kong has increased more significantly during the same period, reflecting contributions from southern/eastern China. The combined result is a rise in O3 and a nondecrease in O x . This study highlights the urgent need for close cross-boundary cooperation to mitigate the O3 problem in Hong Kong. China’s air pollution control policy applies primarily to its large cities, with little attention to developing areas elsewhere. The experience of Hong Kong suggests that this control policy does not effectively address secondary pollution, and that a coordinated multiregional program is required.
Circularly polarized luminescence (CPL) switching has attracted great attention due to the potential applications in chiral photonics and electronics. However, the lack of examples to achieve ...switchable CPL within a single material in the dry solid state hampers the scope of applications. Herein, we demonstrate a crystalline chiral polymer film as a polarizing medium consisting of radially assembled twisted crystallites, where achiral aggregation-induced emissive luminogens (AIEgens) are confined between the twisted crystalline stacks, eventually yielding handedness-switchable CPL by simple film tilting. Hierarchically organized twisted crystallites create the selective reflection activity of the polarizing medium. Upon film tilting, enantiomeric switching is realized by selectively collecting transmitted and reflected CPL components. The confined AIEgens in the crystalline polarizing system show a great enhancement of the luminescence efficiency. Moreover, the approach is general with broadband activity, and various AIEgens could be applied to generate full-color-tunable CPL. Additionally, the rigid and continuous nature of this polarizing system affords enhanced optical stability and facile modulation, developing a general route for designing chiroptical materials.
Nonradiative decay invariably competes with radiative decay during the deexcitation process of matter. In the community of luminescence research, nonradiative decay has been deemed less attractive ...than radiative decay. However, all things in their being are good for something and so is nonradiative decay. As the molecular motion‐facilitated nonradiative decay (MMFND) effect is inevitable in photophysical processes, it provides a new avenue to convert the harvested light energy into exploitable forms by harnessing molecular motion. In many cases, active molecular motion enables thermal deactivation from excited states. In this Minireview, recent advances in photothermal and photoacoustic systems with MMFND character are summarized. We believe that this presentation of the rational engineering of molecular motion for efficient photothermal generation will deepen the understanding of the relationship between molecular motion and nonradiative decay and navigate people to rethink the positive aspects of nonradiative decay for the establishment of new light‐controllable techniques.
In the past few years, the molecular motion‐facilitated nonradiative decay (MMFND) effect has been widely used to develop efficient photothermal and photoacoustic systems. To give a timely summary of this emerging field, the present Minireview systematically highlights the underlying mechanism, molecular design principles, and advanced applications of photothermal transduction agents with flexible molecular groups.
Abstract
Interplay between EBV infection and acquired genetic alterations during nasopharyngeal carcinoma (NPC) development remains vague. Here we report a comprehensive genomic analysis of 70 NPCs, ...combining whole-genome sequencing (WGS) of microdissected tumor cells with EBV oncogene expression to reveal multiple aspects of cellular-viral co-operation in tumorigenesis. Genomic aberrations along with EBV-encoded LMP1 expression underpin constitutive NF-κB activation in 90% of NPCs. A similar spectrum of somatic aberrations and viral gene expression undermine innate immunity in 79% of cases and adaptive immunity in 47% of cases; mechanisms by which NPC may evade immune surveillance despite its pro-inflammatory phenotype. Additionally, genomic changes impairing
TGFBR2
promote oncogenesis and stabilize EBV infection in tumor cells. Fine-mapping of
CDKN2A/CDKN2B
deletion breakpoints reveals homozygous
MTAP
deletions in 32-34% of NPCs that confer marked sensitivity to MAT2A inhibition. Our work concludes that NPC is a homogeneously NF-κB-driven and immune-protected, yet potentially druggable, cancer.
Hyperuricemia (HUA) is associated with the prevalence of metabolic syndrome (MetS) and cardiovascular risks in various populations. HUA is also able to induce cardiomyocyte hypertrophy in mouse ...models. However, the dose-response effects of serum uric acid (SUA) on the prevalence of MetS and electrocardiographic left ventricular hypertrophy (LVH) are unclear.
We retrospectively collected data from 18,932 individuals who underwent an annual health examination between 1/1/2016 and 12/31/2016. We excluded those with systemic diseases or missing questionnaires. The primary study endpoints were the prevalence of MetS and LVH, which were defined by the criteria for the Taiwanese population and the “SPRINT” trial. The cohort consisted of 17,913 individuals with a mean age of 31.2 years (SD 7.4) and a mean body mass index of 24.6 kg/m2 (SD 3.6); 87.1% of the individuals were men. The prevalence rates of HUA, MetS, and LVH were 29.5%, 9.4%, and 0.32%, respectively, in the overall study population. The HUA group was predominantly male and had significantly poorer lifestyle choices and greater laboratory cardiometabolic biomarker values than did the normouricemic group. However, the frequencies of physical activity were comparable between the two groups. After adjusting for confounders, SUA was associated with MetS (OR:1.473, 95% CI:1.408–1.540, P < 0.001) and LVH (OR:1.301, 95% CI:1.064–1.591, P = 0.01).
We demonstrated that the dose-response effects of SUA are associated with the prevalence of MetS and electrocardiographic LVH in healthy individuals from Taiwan. Based on this evidence, future studies should investigate urate-lowering therapy and cardiovascular benefits in individuals with HUA (ClinicalTrials.gov number NCT03473951).
•Serum uric acid (SUA) was associated with the prevalence of metabolic syndrome and LVH.•The association is independent of life style choice and physical activity.•The association did not change with adjustment for kidney function.•Future studies might evaluate urate-lowering effects on the improvement of metabolic syndrome and LVH.
Click polymerization Qin, Anjun; Lam, Jacky W Y; Tang, Ben Zhong
Chemical Society reviews
39, Številka:
7
Journal Article
Recenzirano
Odprti dostop
The development of new polymerization reactions is of critical importance to macromolecule science. In this critical review, we summarize the research efforts to incubate alkyne-azide click reactions ...into a versatile polymerization technique for the synthesis of poly(triazole)s (PTAs) with linear and hyperbranched structures. Cu(I)- and Ru(II)-catalyzed click polymerizations afforded 1,4- and 1,5-regioregular PTAs, respectively. Whereas traditional thermal cycloadditions normally generate regiorandom products, PTAs with 1,4-regioisomer contents up to 95% were created by utilizing the electronic effect involved in the thermal click polymerizations of aroylacetylenes with azides. The PTAs showed unique functional properties, such as luminescence, chromism, fluorescence imaging, emission superquenching, chain helicity, optical nonlinearity, light refractivity, photovoltaic effect, cytocompatibility and biodegradability (145 references).
In this study, a reactive phosphorus-containing organoclay (RPC) was successfully prepared through the cationic exchange reaction of sodium montomorillonite clay with hexyltriphenylphosphonium ...bromide and surface modification by grafting it with glycidyloxypropyltrimethoxy silane. It is characterized using X-ray diffraction (XRD) and Fourier transform IR (FTIR) measurements. A series of novel epoxy/clay nanocomposites (ERPC) was then prepared with a selected epoxy resin and varying amounts of RPC. The results of XRD and TEM of the nanocomposites showed that the RPC particles were well dispersed in the epoxy matrix with a highly exfoliated structure due to the presence of the reactive epoxide group of RPC. The as-prepared epoxy/RPC nanocomposites (ERPC) were thermally stable up to 388°C. Thermal stability was increased by increasing the RPC content as indicated by the corresponding activation energies (Ea) and the integral procedural decomposition temperatures (IPDT). Furthermore, the storage modulus in the glass state of the nanocomposites was dramatically increased with the increase in RPC content. In addition, the large increment of limiting oxygen index (LOI) which was 11 units higher than that of the neat epoxy indicates that an extraordinary enhancement of flame retardancy was obtained from the nanocomposite containing 5wt% of RPC.
Display omitted
Multimodality imaging is highly desirable for accurate diagnosis by achieving high sensitivity, spatial–temporal resolution, and penetration depth with a single structural unit. However, it is still ...challenging to integrate fluorescent and plasmonic modalities into a single structure, as they are naturally incompatible because of significant fluorescence quenching by plasmonic noble-metal nanoparticles. Herein, we report a new type of silver@AIEgen (aggregation-induced emission luminogen) core–shell nanoparticle (AACSN) with both strong aggregated-state fluorescence of the AIEgen and distinctive plasmonic scattering of silver nanoparticles for multimodality imaging in living cells and small animals. The AACSNs were prepared through a redox reaction between silver ions and a redox-active AIEgen, which promoted synergistic formation of the silver core and self-assembly of the AIEgen around the core. The resulting AACSNs exhibited good biocompatibility and high resistance to environmental damage. As a result, excellent performance in fluorescence imaging, dark-field microscopy, and X-ray computed tomography-based multimodality imaging was achieved.
PDF
