Preparation of gelatin-chitosan bilayer film loaded citral nanoemulsion as pH and enzyme stimuli-responsive antibacterial material for food packaging.

The responsive release of enzymes, pH, temperature, light and other stimuli is an effective means to reduce the loss of volatile active substances and control the release of active ingredients. The purpose of this study is to design a simple and rapid method to synthesize a multifunctional bilayer membrane, which has good mechanical properties, long-lasting pH and enzyme dual sensitive sustained release properties, and excellent antibacterial activity. The citral nanoemulsion was prepared by ultrasonic method, then the chitosan solution loaded with nanoemulsion was assembled on the gelatin film, and the uniform and smooth gelatin-chitosan bilayer film was successfully prepared. Compared with the control group, the bilayer film loaded with nanoemulsion showed better barrier performance, mechanical properties and antibacterial activity.

Linewidth narrowing of aluminum breathing plasmon resonances in Bragg grating decorated nanodisks.

Plasmon resonances with high-quality are of great importance in light emission control and light-matter interactions. Nevertheless, inherent ohmic and radiative losses usually hinder the plasmon performance of metallic nanostructures, especially for aluminum (Al). Here we demonstrate a Bragg grating decorated nanodisk to narrow the linewidth of breathing plasmon resonances compared with a commensurate nanodisk. Two kinds of plasmon resonant modes and the corresponding mode patterns are investigated in cathodoluminescence (CL) depending on the different electron bombardment positions, and the experimental results agree well with full wave electromagnetic simulations. Linewidth narrowing can be clearly understood using an approximated magnetic dipole model. Our results suggest a feasible mechanism for linewidth narrowing of plasmon resonances as well as pave the way for in-depth analysis and potential applications of Al plasmon systems.

Possible pharmaceutical applications can be developed from naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids.

Naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids (PIAs and PQAs) are two small groups of herbal metabolites sharing a similar pentacyclic structure with a highly oxygenated phenanthrene moiety fused with a saturated or an unsaturated N-heterocycle (indolizidine/quinolizidine moieties). Natural PIAs and PQAs only could be obtained from finite plant families (such as Asclepiadaceae, Lauraceae and Urticaceae families, etc.). Up to date, more than one hundred natural PIAs, while only nine natural PQAs had been described. PIA and PQA analogues have been applied to the development of potent anticancer agents all along because of their excellent cytotoxic activity. However, in the last two decades, other great biological properties, such as anti-inflammatory and antiviral activities were revealed successively by different pharmacological assays. Especially because of their potent antiviral activity against coronavirus (TGEV, SARS CoV and MHV) and tobacco mosaic virus, PIA and PQA analogues have attracted much pharmaceutical attention again, some of them have been used to present interesting targets for total or semi synthesis, and structure-activity relationship (SAR) study for the development of antiviral agents. In this review, natural PIA and PQA analogues obtained in the last two decades with their herbal origins, key spectroscopic characteristics for structural identification, biological activity with possible SARs and application prospects were systematically summarized. We hope this paper can stimulate further investigations on PIA and PQA analogues as an important source for potential drug discovery.

Recovery Responses of Central Hemodynamics in Basketball Athletes and Controls After the Bruce Test.

PURPOSE: It is commonly believed that central hemodynamics is closely associated with the presence of cardiovascular events. However, controversial data exist on the acute response of competitive sports on central hemodynamics. Moreover, the central hemodynamic response to exercise is too transient to be investigated. Therefore, this study aimed to investigate the central hemodynamic response in young basketball athletes and controls after 1 h recovery after exercise. METHODS: Fifteen young basketball athletes and fifteen aged-matched controls were recruited to perform the Bruce test. Central hemodynamics were measured and calculated, including heart rate (HR), aortic systolic, diastolic, and pulse pressure (ASP, ADP, and APP), ejection duration (ED), sub-endocardial viability ratio (SEVR), central augmentation index (AIx), and AIx@HR75. Intra-group and inter-group differences were analyzed by two-way repeated measures ANOVA. RESULTS: ASP significantly decreased at 10 min after exercise in athletes, while it markedly declined at 15 min after exercise in controls (p < 0.01). Additionally, only in the athlete group, ADP significantly decreased at 50 min and at 1 h after exercise. AIx was also significantly reduced at 1-2, 20, 30, and 40 min after exercise (all p < 0.05). Moreover, there were significant differences in the changes of these parameters between the two groups at these measurement points (p < 0.05). SEVR significantly recovered to the baseline level after 30 min, while ED and HR returned to baseline levels at 40 min after exercise in both groups. CONCLUSION: Sustained decrease of aortic BPs was sooner after the cessation of exercise in athletes than in controls, and changes of aortic stiffness were more evident in athletes than those in controls during the 1 h recovery period. Additionally, SEVR returned to the baseline sooner than ED and HR in athletes.

Ultrastrong coupling of CdZnS/ZnS quantum dots to bonding breathing plasmons of aluminum metal-insulator-metal nanocavities in near-ultraviolet spectrum.

Strong coupling originating from excitons of quantum dots and plasmons in nanocavities can be realized at room temperature due to the large electromagnetic field enhancement of plasmons, offering building blocks for quantum information systems, ultralow-power switches and lasers. However, most of the current strong coupling effects were realized by the interaction between excitons and far-field light excited bright plasmon modes in the visible range. Beyond that, there is still a lack of direct imaging of polariton modes at the nanoscale. In this work, by using cathodoluminescence, ultrastrong coupling with Rabi splitting exceeding 1 eV between bonding breathing plasmons of aluminum (Al) metal-insulator-metal (MIM) cavities and excited states of CdZnS/ZnS quantum dots was observed in the near-ultraviolet (UV) spectrum. Further, the hybridization of the QDs excitons and bonding breathing plasmonic modes is verified by deep-subwavelength images of polaritonic modes in real-space. Analytic analysis based on the coupled oscillator model and full-wave electromagnetic simulations is consistent with our experimental results. Our work not only indicates the great potential of electron excited plasmon modes for strong coupling applications, but also extends the polaritonic frequency to the UV range with Al nanocavities.

Undescribed C-geranylflavonoids isolated from the fruit peel of Paulownia catalpifolia T. Gong ex D.Y. Hong with their protection on human umbilical vein endothelial cells injury induced by hydrogen peroxide.

Six undescribed C-geranylated flavonoids, including five C-geranylflavanones named as paucatalinones F - J, one C-geranylflavonol named as paucatalinone K, along with seven known geranylated flavanones, were isolated from the fruit peel of Paulownia catalpifolia T. Gong ex D.Y. Hong. Their structures were elucidated distinctly according to their UV, IR, MS, NMR, and CD data. Among them, two compounds were substituted with unusual modified geranyl groups, namely paucatalinone F with an oxygenated cyclogeranyl substituent and paucatalinone H with a terminal pyranoid geranyl substituent. Furthermore, the protective effects on human umbilical vein endothelial cells (HUVECs) injury induced by H2O2 were evaluated, and paucatalinone F showed the most potential activity. The bioactive results suggested that the geranyl substituent may be an important factor for restraining oxidative HUVECs damage and Paulownia C-geranylated flavonoids might have the potential for preventing cardiovascular complications.

Cathodoluminescence nanoscopy of open single-crystal aluminum plasmonic nanocavities.

Exact understanding of the plasmon response of aluminum (Al) nanostructures in deep subwavelengths is critical for the design of Al based plasmonic applications, such as the emission control of quantum dots and surface-enhanced resonance Raman scattering in the ultraviolet (UV) range. Here, the plasmonic properties of open triangle cavities patterned by a focused ion beam in single-crystal bulk Al were explored using cathodoluminescence. The resonant modes were determined by experimental spectra and deep subwavelength real-space mode patterns ranging from the visible to the UV, which agreed well with full-wave electromagnetic simulations. The dispersion relation of the cavity modes was consistent with that at the interface between Al and vacuum, showing strong electromagnetic field confinement in the cavities. Open Al triangle cavities provided room for the interaction between optical emitters and confined electromagnetic fields, paving the way for plasmonic devices for a variety of applications, such as plasmonic light-emitting devices or nanolasers in the UV range.

Comparison of central hemodynamic parameters for young basketball athletes and control group.

BACKGROUND: Long-term exercise training may have negative effects on cardiovascular functions. Measurement and calculation of central hemodynamic parameters can comprehensively evaluate the cardiovascular functions. This study aims to compare the central hemodynamics between young basketball athletes and matched controls. METHODS: Total 19 young long-term trained male basketball athletes and 17 matched male recreationally active controls participated. The central hemodynamic parameters such as central blood pressure, pulse pressure, heart rate (HR), augmentation index normalised to 75 bpm (AIx@HR75), augmentation index (AIx), ejection duration (ED), sub-endocardial viability ratio (SEVR) were measured, and total peripheral resistance (TPR), stroke volume (SV) and cardiac output (CO) were calculated. Non-parameter tests and t-test were used to analyse the central hemodynamic parameters between athletes and controls. RESULTS: HR (56 ± 5 bpm versus 79 ± 9 bpm, p < .001), AIx@HR75 (-8 ± 10% versus -1 ± 10%, p < .05), ED (28 ± 2% versus 36 ± 3%, p < .001) and TPR (0.004 ± 0.006 mmHg s/mL versus 0.012 ± 0.006 mmHg s/mL, p < .001) were significantly lower in basketball athletes compared to the controls. SEVR (231 ± 32% versus 159 ± 21%, p < .001) and SV (154 ± 50 mL versus 101 ± 43 mL, p < .01) were significantly higher in basketball athletes than those in the controls. However, there were no significant differences in central blood pressure, pulse pressure, AIx and CO between them. CONCLUSIONS: There is no negative effect on central hemodynamics in young basketball athletes after long-term exercise training. The young basketball athletes have a higher myocardial perfusion, higher efficiency of blood supply, stronger vascular functions and better balance of myocardial oxygen of supply and demand than the controls in this central hemodynamic parameters analysis.

Unveiling quasi-dark surface plasmon modes in Au nanoring cavities by cathodoluminescence.

Spectral resolving and imaging surface plasmon modes in noble metal nanostructures are important for applications in nanophotonics. Here, we use cathodoluminescence (CL) spectroscopy to excite and probe quasi-dark plasmon modes of Au nanoring cavities. Numerical simulations of both the spectra and the electromagnetic field distribution are carried out by using boundary element method. Good agreement between the experimental and simulated results is obtained. Particularly, CL is shown as an efficient method to probe quadrupole modes, which is difficult for traditional optical means. Moreover, a high Purcell factor in excess of 100 is obtained for the dark quadrupole modes in gold ring cavities. Our work provides an efficient way to explore the initial nature of surface plasmon modes in metal nanostructures.

Substrate carrier concentration dependent plasmon-phonon coupled modes at the interface between graphene and semiconductors.

The coupled modes between graphene plasmons and surface phonons of a semiconductor substrate are investigated, which can be efficiently controlled by carrier injection of the substrate. A new physical mechanism on tuning plasmon-phonon coupled modes (PPCMs) is proposed due to the fact that the energy and lifetime of substrate surface phonons depend a lot on the carrier concentration. Specifically, the change of dispersion and lifetime of PPCMs can be controlled by the carrier concentration of the substrate. The energy of PPCMs for a given momentum increases as the carrier concentration of the substrate increases. On the other hand, the momentum of PPCMs for a given energy decreases when the carrier concentration of the substrate increases. The lifetime of PPCMs is always larger than the intrinsic lifetime of graphene plasmons without plasmon-phonon coupling.

Mid-infrared plasmon induced transparency in heterogeneous graphene ribbon pairs.

The control of coherent phenomena in graphene structures is proposed. Specifically, plasmon induced transparency (PIT) effect is investigated in a kind of simple graphene structures - graphene ribbon pairs. The transparency effect are understood by the mode coupling between dipolar and quadrupole plasmons modes in graphene ribbons. By using bias voltage tuning or geometry parameters changing, the PIT effect can be effectively controlled, which is based on the frequency tuning of dipolar or quadrupole modes in ribbons. These properties make these structures possess applications in two-dimensional plasmonics devices in mid-infrared range. In addition, the tuning of PIT in graphene ribbon pairs opens an avenue for active coherent control in plasmonics.