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Evaluation of the effects of photodynamic therapy with hypericin-glucamine in the treatment of periodontal disease induced in rats
摘要： Purpose The purpose of this study was to evaluate the effectiveness of a photosensitizer hypericin-glucamine, activated by LED amber (34.10 J/cm2) as an adjuvant to scaling and root planing (SRP), on the treatment of experimental periodontal disease (PD) in rats. Methods In a 15-day period, PD was induced in the mandibular molars through ligature placement. The animals (n = 60) were randomly divided into four groups: control (with induction of periodontal disease), scaling and root planing (SRP), antimicrobial photodynamic therapy (aPDT), and SRP + aPDT. At 7, 15, and 30 days after treatments, animals were euthanized. Digital microtomography, histometric, and stereometric analyses were performed to calculate the bone loss of mandibular second molars, and the tissue repair was analyzed histologically. The data were subjected to statistical analysis (α = 5%). Results Histologically, the control group periodontium showed several morphological changes, but an evident gradual reduction in the inflammatory process was observed in the subsequent periods. The SRP, aPDT, and SRP + aPDT groups presented the same, but in less intensity. The stereometric analysis showed a significantly higher proportion of fibroblasts in SRP group (p < 0,001) and SRP + aPDT group (p < 0.0001) compared to that in the control group at 7 days post treatment. Conclusions We conclude that scaling and root planing with or without photodynamic therapy with hypericin-glucamine increased density of the fibroblast and cell density. However, there is no statistically significant difference between SRP and SRP + aPDT.
关键词： Periodontal disease,Hypericin-glucamine,Scaling and root planing
更新于2025-09-23 15:22:29
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Analytical Thomson backscattering spectra and new scaling laws in laser and magnetic fields
摘要： The analytical asymptotic expression of Thomson backscattering spectra in arbitrarily polarized laser and uniform magnetic fields is given. It is used to theoretically analyze the spectra structures and properties. The results of asymptotic expression and numerical calculations show good agreement in the large harmonic-order region. The scaling laws about laser intensity and electron initial axial momentum are obtained. Furthermore, the optimal harmonic order corresponding to the maximum radiation intensity can be found, then new scaling laws about this optimal harmonic order with laser intensity and resonance parameter are revealed.
关键词： scaling laws,magnetic fields,laser fields,Thomson backscattering
更新于2025-09-23 15:21:01
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Demonstration of Scale-Invariant Rayleigh-Taylor Instability Growth in Laser-Driven Cylindrical Implosion Experiments
摘要： Rayleigh-Taylor instability growth is shown to be hydrodynamically scale invariant in convergent cylindrical implosions for targets that varied in radial dimension and implosion timescale by a factor of 3. The targets were driven directly by laser irradiation providing a short impulse, and instability growth at an embedded aluminum interface occurs as it converges radially inward by a factor of 2.25 and decelerates on a central foam core. Late-time growth factors of 14 are observed for a single-mode m ? 20 azimuthal perturbation at both scales, despite the differences in laser drive conditions between the experimental facilities, consistent with predictions from radiation-hydrodynamics simulations. This platform enables detailed investigations into the limits of hydrodynamic scaling in high-energy-density systems.
关键词： high-energy-density physics,hydrodynamic scaling,laser-driven implosions,Rayleigh-Taylor instability
更新于2025-09-23 15:21:01
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<i>(Invited) The Scaling-Down and Performance Optimization of InAs Nanowire Field Effect Transistors</i>
摘要： Due to their fascinating properties, InAs nanowires have drawn great attention for the channel material in future transistors. Scaling-down has been an effective way to improve the performance of transistors continuously for decades. Here, we review our recent progresses on InAs nanowire field effect transistors (FETs) when they are scaled down. Our group investigates the electrical characteristics of InAs nanowire thinner than 10 nm. Both the size-effect and the contact properties of ultrathin nanowires are explored. Moreover, the effects of InAs crystal phase and orientation are studied for further optimizing the device performance. In addition, FETs with partial gate are studied to suppress the BTBT-induced off-current. Furthermore, to improve the electrostatics control of the gate, our group develops a method to fabricate vertical GAA FETs with all-metal electrodes based on self-catalyzed grown InAs nanowire arrays.
关键词： orientation,crystal phase,performance optimization,field effect transistors,partial gate,vertical GAA FETs,InAs nanowires,scaling-down
更新于2025-09-23 15:21:01
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Structural properties of silicon–germanium and germanium–silicon core–shell nanowires
摘要： Core–shell nanowires made of Si and Ge can be grown experimentally with excellent control for different sizes of both core and shell. We have studied the structural properties of Si/Ge and Ge/Si core–shell nanowires aligned along the [1 1 0] direction, with diameters up to 10.2 nm and varying core to shell ratios, using linear scaling density functional theory. We show that Vegard’s law, which is often used to predict the axial lattice constant, can lead to an error of up to 1%, underlining the need for a detailed ab initio atomistic treatment of the nanowire structure. We analyse the character of the intrinsic strain distribution and show that, regardless of the composition or bond direction, the Si core or shell always expands. In contrast, the strain patterns in the Ge shell or core are highly sensitive to the location, composition and bond direction. The highest strains are found at heterojunction interfaces and the surfaces of the nanowires. This detailed understanding of the atomistic structure and strain paves the way for studies of the electronic properties of core–shell nanowires and investigations of doping and structure defects.
关键词： Vegard’s law,nanowire,linear scaling density functional theory,core–shell
更新于2025-09-23 15:21:01
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Scaling-up UV-mediated Intramolecular-Photo-Dehydro-Diels-Alder reactions using a Homemade High-Performance Annular Continuous-Flow Reactor
摘要： In this communication, we present a self-made annular continuous-flow reactor, which can be used in the UV/Vis-range in an internal numbering-up manner. As a model reaction, we chose a powerful and batch scale-limited benzoannelation method, which is an intramolecular Photo-Dehydro-Diels-Alder (IMPDDA) reaction. The scaling-up potential of this particular photochemical benchmark reaction towards the preparation of macrocylic (1,7)naphthalenophanes by variation of selected flow parameters is presented.
关键词： flow photochemistry,scaling-up,photocycloaddition,Photo-Dehydro-Diels-Alder reaction
更新于2025-09-23 15:21:01
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Numerical studies of residual states and scaling effects in laser-directed energy deposition additive manufacturing
摘要： Sequentially coupled thermo-mechanical model was used to simulate the residual stresses and residual distortions in the directed energy deposition additive manufacturing by laser. The proposed models were validated by comparison with experimental data. Different sizes of components were used to study the scaling effects. Results indicate that the residual stress can be controlled by the component sizes. This phenomenon can be explained by the bending deformation and the temperature fluctuations, especially the cooling rate, in the directed energy deposition additive manufacturing process. Both the bending deformation and the temperature fluctuations can be controlled by the ambient temperature and the designed process parameters. Analytical model was established to show how the components’ sizes affect the final residual states in combination with different design parameters.
关键词： Scaling effect,Residual stress,Residual distortion,Additive manufacturing
更新于2025-09-23 15:19:57
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Study on the thermal initiation of shelled PBXN-109 under laser irradiation
摘要： In order to investigate the thermal initiation mechanism of a warhead under laser irradiation, small scale experiments have been carried out with shelled PBXN-109 to obtain the initiation time and critical metal temperature. It was found that, as the laser power increases, the initiation time decreases exponentially; while the critical metal temperature increases linearly due to the effect of thermal conduct resistance. Based on theoretical analysis, a prediction model was built with a good accuracy for engineering application. In order to establish the relationship between the small-scale and the full-scale experiments, the scaling law of the thermal response process was approximated with that of the thermal conduct process, which was deduced through equation analysis to avoid the difficulty brought by the exponential nonlinearity from the equation of the thermal decomposition of the explosive.
关键词： laser,PBXN-109,metal,initiation,scaling law
更新于2025-09-23 15:19:57
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Ultra-scaled MoS<sub>2</sub> transistors and circuits fabricated without nanolithography
摘要： The future scaling of semiconductor devices can be continued only by the development of novel nanofabrication techniques and atomically thin transistor channels. Here we demonstrate ultra-scaled MoS2 field-effect transistors (FETs) realized by shadow evaporation method which does not require nanofabrication. The method enables large-scale fabrication of MoS2 FETs with fully gated 10-nm long channels. The realized ultra-scaled MoS2 FETs exhibit very small hysteresis of current-voltage characteristics, record high drain currents of ～ 560 A/m, very good drain current saturation for such ultra-short devices, subthreshold swing ～ 120 mV/dec, and drain current on/off ratio ～ 106 in air ambient. The fabricated ultra-scaled MoS2 FETs are also used to realize logic gates in n-type depletion-load technology. The inverters exhibit a voltage gain of ～ 50 at a power supply voltage of only 1.5 V and are capable of in/out signal matching.
关键词： transistor scaling,field-effect transistors,logic gates,MoS2,short-channel effects
更新于2025-09-23 15:19:57
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Abnormal scaling of excitons in phosphorene quantum dots
摘要： Excitonic states of a many-electron system in phosphorene quantum dots (PQDs) are investigated theoretically by using a configuration interaction approach. For a triangular PQD in various dielectric environments, its exciton is found to obey two distinct scaling rules. When there is strong screening effect present in the nanodot, the exciton binding energy (?ex) is shown to be around ?150 meV as the long-range Coulomb interactions are totally suppressed and increases to about 100 meV when the effective dielectric constant (εr) decreases to 12.5. Over this range of εr, ?ex is found to be well fitted into a quadratic form of ε?1 r like the case of bulk three-dimensional semiconductors nor linearly with ε?1 r like the case previously reported for graphene nanostructures. When εr is reduced below 10.0, however, ?ex is shown to exhibit a perfect linear relation with ε?1 r, which behaves just like that of a two-dimensional graphene sheet. On the other hand, with the reduced εr, the quasiparticle gap is found to decrease instead of increase like in most of semiconductor nanostructures. As a result, it is revealed that the relationship of ?ex with the quasi-particle gap deviates largely from the linear one previously reported for graphene and many other two-dimensional materials.
关键词： excitonic states,dielectric environments,phosphorene quantum dots,scaling rules,configuration interaction approach
更新于2025-09-23 15:19:57