Boosting Light-Matter Interactions in Plasmonic Nanogaps.

Plasmonic nanogaps in strongly coupled metal nanostructures can confine light to nanoscale regions, leading to huge electric field enhancement. This unique capability makes plasmonic nanogaps powerful platforms for boosting light-matter interactions, thereby enabling the rapid development of novel phenomena and applications. This review traces the progress of nanogap systems characterized by well-defined morphologies, controllable optical responses, and a focus on achieving extreme performance. The properties of plasmonic gap modes in far-field resonance and near-field enhancement are explored and a detailed comparative analysis of nanogap fabrication techniques down to sub-nanometer scales is provided, including bottom-up, top-down, and their combined approaches. Additionally, recent advancements and applications across various frontier research areas are highlighted, including surface-enhanced spectroscopy, plasmon-exciton strong coupling, nonlinear optics, optoelectronic devices, and other applications beyond photonics. Finally, the challenges and promising emerging directions in the field are discussed, such as light-driven atomic effects, molecular optomechanics, and alternative new materials.

Chyle leakage after laparoscopic cholecystectomy in a patient with duplicated cystic ducts: A case report and literature review.

RATIONALE: Laparoscopic cholecystectomy (LC) is widely performed as a standard treatment for cholelithiasis, and chyle leakage after LC has rarely been reported. Duplicated cystic ducts draining a single gallbladder is an extraordinarily rare variation. PATIENT CONCERNS: We presented a case of chyle leakage after LC in a 53-year-old female with a rare variation of duplicated cystic ducts. DIAGNOSES: Chyle leakage and duplicated cystic ducts. INTERVENTIONS: Conservative treatment including lipid intake and constant drainage. OUTCOMES: After 24 days of conservative treatment, the patient recovered and had no further troubles during the 3-month follow-up. LESSONS: There may be a potential relationship between anatomic variants of the extrahepatic bile ducts and those of the lymphatic system. When anatomic variations of the extrahepatic bile ducts are encountered, vigilance for lymphatic system injuries is as important as vigilance for bile duct injuries. Conservative therapy is the first choice for postoperative chyle leakage, and surgical intervention should be considered in cases with high-volume chyle leakage.

Identification of salivary proteins in the rice leaf folder Cnaphalocrocis medinalis by transcriptome and LC-MS/MS analyses.

Salivary proteins in the oral secretion (OS) of chewing insects play a crucial role in insect-plant interactions during feeding. The rice leaf folder Cnaphalocrocis medinalis, a notorious pest in global rice production, triggers defense responses during feeding, but little is known about its salivary proteins. In this study, we confirmed that C. medinalis releases OS during feeding. By employing transcriptomic analysis and liquid chromatography-tandem mass spectroscopy (LC-MS/MS), we examined the salivary proteins from labial salivary glands and OS from C. medinalis. A total of 14,397 genes were expressed at the RNA level and 229 salivary proteins were identified. Comparative analysis with other 25 arthropod species revealed that 43 proteins were unique to C. medinalis. Expression pattern analysis revealed that most of the selected genes were highly expressed in the gut and the larval stages (4th-5th instar). These findings provide a comprehensive resource for future functional studies of salivary proteins, offering new insights into the molecular mechanisms by which C. medinalis modulates plant defenses and potential applications in pest management.

Quantifying the ultimate limit of plasmonic near-field enhancement.

Quantitatively probing the ultimate limit of near-field enhancement around plasmonic nanostructures remains elusive, despite more than five decades since the discovery of surface-enhanced Raman scattering. Theoretical calculations have predicted an ultimate near-field enhancement exceeding 1000 using the best plasmonic material silver, but experimental estimations disperse by orders of magnitude. Here, we design a high-quality silver plasmonic nanocavity with atomic precision and precisely quantify the upper limit of near-field enhancement in ~1 nm junctions. A hot-spot averaged Raman enhancement of 4.27 × 1010 is recorded with a small fluctuation, corresponding to an averaged electric field enhancement larger than 1000 times. This result quantitatively delineates the ultimate limit of plasmonic field enhancement around plasmonic nanostructures, establishing a foundation for diverse plasmon-enhanced processes and strong light-matter interactions at the atomic scale.

Unraveling the Origin of Reverse Plasmonic Circular Dichroism from Discrete Bichiral Au Nanoparticles.

Bichiral plasmonic nanoparticles exhibited intriguing geometry-dependent circular dichroism (CD) reversal; however, the crucial factor that dominates the plasmonic CD is still unclear. Combined with CD spectroscopy and theoretical multipole analysis, we demonstrate that plasmonic CD originates from the excitation of electric quadrupolar plasmons. Moreover, a comparative study of two distinct quadrupolar modes reveals the correlation between the sign of the CD and the local geometric handedness at the plasmonic hotspots, thereby establishing a structure-property relationship in bichiral nanoparticles. The reverse CD is attributed to the opposite directions of the wavelength shift of the two plasmon modes upon changing the particle geometry. By finely tuning the size of bichiral nanoparticles, we can further reveal that the dependence of plasmonic CD on the electric quadrupolar plasmons. Our work sheds light on the physical origin of plasmonic CD and provides important guidelines for the design of chiral plasmonic nanoparticles toward chirality-dependent applications.

Probing Topological Thermal Flux in Equilibrium Using Electron Beams.

Near nonreciprocal media at finite temperature, fluctuating near fields exhibit imbalanced thermal populations in opposite directions, generating equilibrium topological thermal fluxes that circulate the media. While the existence of these fluxes remains unconfirmed, we propose exploiting their interaction with free electron beams for detection. We establish a general framework to quantify thermal flux at any location near an object of arbitrary shape. This reveals unexplored properties of thermal flux spectra depending on their orientation. Further, we connect the electron scattering rate to the equilibrium thermal flux. As a specific example, electrons encountering a planar surface's perpendicular thermal flux preferentially scatter transversely. This measurable scattering distribution, i.e., via angle-resolved electron microscopy, allows us to recover the thermal flux spectrum. Additionally, electron interactions with equilibrium thermal fluxes surrounding local structures offer a novel approach to generating electron vortex beams.

Chromosome-level genome assembly from a single planthopper Nilaparvata muiri (Hemiptera: Delphacidae).

The planthopper Nilaparvata muiri is a sister species to N. lugens (Hemiptera: Delphacidae), a notorious insect pest in Asian rice fields. N. muiri and N. lugens have a different host preference despite the similarities in many biological features. To better understand the adaptive evolution of planthoppers, comprehensive genomic information on N. muiri and N. lugens are urgently needed. In this study, we used ultra-low input PacBio HiFi libraries and Hi-C sequencing technologies to assemble a reference genome of a single N. muiri at the chromosomal level. The genome size was determined to be 531.62 Mb with a contig N50 size of 2.47 Mb and scaffold N50 size of 38.37 Mb. Totally, 96.61% assembled sequences were anchored to the 15 pseudo-chromosomes. BUSCO analysis yielded an Insecta completeness score of 98.6%. A total of 22,057 protein-coding genes were annotated, and 168.16 Mb repetitive sequences occupying 31.63% of genome were pinpointed. The assembled genome is valuable for evolutionary and genetic studies of planthoppers, and may provide sights to pest control.

Revealing the Properties of Electrically Driven Optical Antennas via Conductive Atomic Force Microscope.

Light emission from ultracompact electrically driven optical antennas (EDOAs) has garnered significant attention due to its terahertz modulation bandwidth. Typically, the EDOAs are fixed and nonadjustable once fabricated, thus hindering the attempts to investigate the influence of structural geometry on light emission properties. Here, we propose and demonstrate that the EDOAs can be constructed by carefully manipulating the gold-coated tips of atomic force microscopy operated in conductive mode into contact with the optical antennas covered by insulating film, where the position of the tunnel junction on the antenna surface can be controlled with high accuracy and flexibility. Taking gold nanorod antennas covered by HfO2 film as an example, we found that the highest light generation efficiency is obtained when the tunnel junction is located at the shoulder edge of the nanorod antenna, where the bonding dipolar surface plasmon mode in the junction is spectrally and spatially coupled with the longitudinal radiation mode of the EDOAs. Besides, position variation of the tunnel junction on the nanorod surface also strongly influences the far-field radiation angular distribution and emission spectrum. Numerical simulations are in good agreement with the experimental results. Our findings offer fundamental insights into the influence of structural parameters on the light emission performance of EDOAs, thus leading to better design of EDOAs with high light generation efficiency and powerful functionality.

Strong light-matter coupling in van der Waals materials.

In recent years, two-dimensional (2D) van der Waals materials have emerged as a focal point in materials research, drawing increasing attention due to their potential for isolating and synergistically combining diverse atomic layers. Atomically thin transition metal dichalcogenides (TMDs) are one of the most alluring van der Waals materials owing to their exceptional electronic and optical properties. The tightly bound excitons with giant oscillator strength render TMDs an ideal platform to investigate strong light-matter coupling when they are integrated with optical cavities, providing a wide range of possibilities for exploring novel polaritonic physics and devices. In this review, we focused on recent advances in TMD-based strong light-matter coupling. In the foremost position, we discuss the various optical structures strongly coupled to TMD materials, such as Fabry-Perot cavities, photonic crystals, and plasmonic nanocavities. We then present several intriguing properties and relevant device applications of TMD polaritons. In the end, we delineate promising future directions for the study of strong light-matter coupling in van der Waals materials.

A Statistical Route to Robust SERS Quantitation Beyond the Single-Molecule Level.

Single-molecule surface-enhanced Raman spectroscopy (SM-SERS) holds great potential to revolutionize ultratrace quantitative analysis. However, achieving quantitative SM-SERS is challenging because of strong intensity fluctuation and blinking characteristics. In this study, we reveal the relation P = 1 - e-α between the statistical SERS probability P and the microscopic average molecule number α in SERS spectra, which lays the physical foundation for a statistical route to implement SM-SERS quantitation. Utilizing SERS probability calibration, we achieve quantitative SERS analysis with batch-to-batch robustness, extremely wide detection range of concentration covering 9 orders of magnitude, and ultralow detection limit far below the single-molecule level. These results indicate the physical feasibility of robust SERS quantitation through statistical route and certainly open a new avenue for implementing SERS as a practical analysis tool in various application scenarios.

Transverse Spin-Orbit Interaction of Light.

Light carries both longitudinal and transverse spin angular momentum. The spin can couple with its orbital counterpart, known as the spin-orbit interaction (SOI) of light. Complementary to the longitudinal SOI known previously, here we show that transverse SOI of light is inherent in the Helmholtz equation when transverse spinning light propagates in curved paths. It lifts the degeneracy of dispersion relations of light for opposite transverse spin states, analogous to the Dresselhaus effect. Transverse SOI is ubiquitous in nanophotonic systems where transverse spin and optical path bending are inevitable. It can explain anomalous effects like the dispersion relation of surface plasmon polaritons on curved paths and the energy level of whispering gallery modes. Our results reveal the analogies of spin photonics and spintronics and offer a new degree of freedom for integrated photonics, spin photonics, and astrophysics.

CRY1 is involved in the take-off behaviour of migratory Cnaphalocrocis medinalis individuals.

BACKGROUND: Numerous insect species undertake long-distance migrations on an enormous scale, with great implications for ecosystems. Given that take-off is the point where it all starts, whether and how the external light and internal circadian rhythm are involved in regulating the take-off behaviour remains largely unknown. Herein, we explore this issue in a migratory pest, Cnaphalocrocis medinalis, via behavioural observations and RNAi experiments. RESULTS: The results showed that C. medinalis moths took off under conditions where the light intensity gradually weakened to 0.1 lx during the afternoon or evening, and the take-off proportions under full spectrum or blue light were significantly higher than that under red and green light. The ultraviolet-A/blue light-sensitive type 1 cryptochrome gene (Cmedcry1) was significantly higher in take-off moths than that of non-take-off moths. In contrast, the expression of the light-insensitive CRY2 (Cmedcry2) and circadian genes (Cmedtim and Cmedper) showed no significant differences. After silencing Cmedcry1, the take-off proportion significantly decreased. Thus, Cmedcry1 is involved in the decrease in light intensity induced take-off behaviour in C. medinalis. CONCLUSIONS: This study can help further explain the molecular mechanisms behind insect migration, especially light perception and signal transmission during take-off phases.

Helicity-Resolved Vibrational Coupling in Twist WS2/WSe2 Heterostructures.

Helicity-resolved Raman spectra can provide an intricate view into lattice structural details. Through the analysis of peak positions, intensities, and circular polarized Raman signals, a wealth of information about chiral structure arrangement within the moiré superlattice, interlayer interaction strength, polarizability change in chemical bond, and beyond can be unveiled. However, the relationship between the circular polarization of high-frequency Raman and twist angle is still not clear. Here, we utilize helicity-resolved Raman spectroscopy to explore the interlayer interactions and the effect of the moiré superlattice in WS2/WSe2 heterostructures. For the out-of-plane Raman mode A1g of WS2 (A1g and 1E2g of WSe2), its intensity is significantly enhanced (suppressed) in WS2/WSe2 heterostructures when θ is less than 10° or greater than 50°. This observation could be attributed to the large polarizability changes in both W-S and W-Se covalent bonds. The circular polarization of 2LA(M) in WSe2 of the WS2/WSe2 heterostructure (θ < 10° or θ > 50°) is significantly enhanced compared to that of 2LA(M) in the monolayer WSe2. We deduce that the circular polarization of the Raman mode correlates with the proportion of high-symmetry area within a supercell of the moiré lattice. Our findings improve the understanding of twist-angle-modulated Raman modes in TMD heterostructures.

Diagnosis and surgical treatment of obturator hernia in the recent decade with long-term follow-up: A single center experience.

Obturator hernia (OH) is a rare and dangerous disease that can lead to life-threatening consequences, and pelvic computed tomography (CT) is widely used for its diagnosis. There is no consensus regarding the surgical approach and repair methods. Retrospective analysis of the clinical and follow-up data of 15 cases of incarcerated hernias patients admitted to the Department of General Surgery, affiliated to Taicang Affiliated Hospital of Soochow University, from January 2011 to December 2022. OH could be precisely diagnosed with pelvic CT scan, except for occult OH and non-strangulated OH. Thirteen patients underwent emergency surgery, with a total complication rate of 76.9% and no mortality. Ten patients underwent open surgery, and 3 patients underwent laparoscopic surgery, which had advantages in terms of total cost and postoperative hospital stay (P < .05). Emergency patients all underwent simple peritoneal closure, and hernial sac excision was simultaneously performed in 6 of them. A recurrence (7.7%) was detected at 38 months after the first operation. There was no statistically significant difference between the 2 tissue repair methods in terms of recurrent rate. Pelvic CT can be used as a gold standard for the diagnosis of incarcerated OH, but it has limited value in occult OH and non-strangulated OH. Laparoscopic surgery is recommended for patients with a short onset time and no abdominal physical signs. Tissue repair is sufficient for incarcerated OH and hernial sac excision may be unnecessary.

Revealing the Optical Transition Properties of Interlayer Excitons in Defective WS2/WSe2 Heterobilayers.

Manipulation of physical properties in multidimensional tunable moiré superlattice systems is a key focus in nanophotonics, especially for interlayer excitons (IXs) in two-dimensional materials. However, the impact of defects on IXs remains unclear. Here, we thoroughly study the optical properties of WS2/WSe2 heterobilayers with varying defect densities. Low-temperature photoluminescence (PL) characterizations reveal that the low-energy IXs are more susceptible to defects compared to the high-energy IXs. The low-energy IXs also show much faster PL quenching rate with temperature, faster peak width broadening rate with laser power, shorter lifetime, and lower circular polarization compared to the low-energy IXs in the region with fewer defects. These effects are attributed to the combined effects of increased electron scattering, exciton-phonon interactions, and nonradiative channels introduced by the defects. Our findings aid in optimizing moiré superlattice structures.

Abamectin exposure causes chronic toxicity and trypsin/chymotrypsin damages in Chironomus kiiensis Tokunaga (Diptera: Chironomidae).

Abamectin has been extensively used in paddy fields to control insect pests. However, little information is available regarding its effects on non-target insects. In this study, we performed acute (3rd instar larvae) and chronic toxicity (newly hatched larvae <24 h) to determine the toxicity effects of abamectin on Chironomus kiiensis. The median lethal concentration (LC50) values of 24 h and 10 d were 0.57 mg/L and 68.12 µg/L, respectively. The chronic exposure significantly prolonged the larvae growth duration and inhibited pupation and emergence. The transcriptome and biochemical parameters were measured using 3rd instar larvae exposed to acute LC10 and LC25 for 24 h. Transcriptome data indicated that five trypsin and four chymotrypsin genes were downregulated, and RT-qPCR verified a significant expression decrease in trypsin3 and chymotrypsin1 genes. Meanwhile, abamectin could significantly inhibit the activities of the serine proteases trypsin and chymotrypsin. RNA interference showed that silencing trypsin3 and chymotrypsin1 genes led to higher mortality of C. kiiensis to abamectin. In conclusion, these findings indicated that trypsin and chymotrypsin are involved in the abamectin toxicity against C. kiiensis, which provides new insights into the mechanism of abamectin-induced ecotoxicity to chironomids.

Differences in adult nutritional requirements impact the population growth and survival of two related species of rice leaffolders to produce interspecific differentiation.

Nutrition is a limiting feature of species evolution. The differences in nutritional requirements are the evolutionary result of differential adaptations to environmental changes, explaining differences in their ecological traits. Cnaphalocrocis medinalis and Cnaphalocrocis exigua, two related species of rice leaffolders, have similar morphology and feeding properties but different migration and overwintering behaviors. However, it is unclear whether they have evolved adult nutritional differentiation traits to coexist. To explore this issue, this study examined the effects of carbohydrates and amino acids on their reproductive and demographic parameters. The findings indicate that carbohydrate intake prolonged the longevity and population growth of two rice leaffolders, but amino acid intake promoted egg hatching only. However, nutrient deficiency made it impossible for C. medinalis to reproduce successfully and survive, but it did not affect C. exigua. The population expansion and survival of migratory C. medinalis relied on adult nutritional intake. Conversely, the nutrients necessary for C. exigua overwintering activity mostly came from the storage of larvae. The difference in nutritional requirements for population growth and survival between the two rice leaffolders partially explained their differences in migration and overwintering.

A multifunctional gingival retraction cord with antibacterial and hemostasis properties based on Chitosan/Propolis/Tranexamic acid for dental treatment.

A novel gingival retraction cord named P/TA@CSy was prepared using chitosan yarns (CSy) loaded with tranexamic acid (TA) and Propolis (P). P/TA@CSy has good toughness with a breaking strength of 41.3 Pa, benefiting from the twisting structure and Propolis coating. A short coagulation time of 456 s was achieved for P/TA@CSy because of the potent blood absorption ability from the effective attachment of tranexamic acid. Moreover, excellent antibacterial ability was obtained with the antibacterial rates against E. coli of 94.73 %, S. aureus of 99.99 % and S. mutans of 99.99 %, contributing to Propolis's antibacterial ability. In addition, suppression of the expression of pro-inflammatory cytokines (IL-6 and TNF-α) was found, which could prevent wound infection. P/TA@CSy displayed excellent cytocompatibility with the cell activity of 100 % after 24 h. Therefore, P/TA@CSy could rapidly respond to gingival hemostasis and infection prevention, showing excellent potential in dental treatment.

All-optical steering on the proton emission in laser-induced nanoplasmas.

Nanoplasmas induced by intense laser fields have attracted enormous attention due to their accompanied spectacular physical phenomena which are vigorously expected by the community of science and industry. For instance, the energetic electrons and ions produced in laser-driven nanoplasmas are significant for the development of compact beam sources. Nevertheless, effective confinement on the propagating charged particles, which was realized through magnetic field modulation and target structure design in big facilities, are largely absent in the microscopic regime. Here we introduce a reliable scheme to provide control on the emission direction of protons generated from surface ionization in gold nanoparticles driven by intense femtosecond laser fields. The ionization level of the nanosystem provides us a knob to manipulate the characteristics of the collective proton emission. The most probable emission direction can be precisely steered by tuning the excitation strength of the laser pulses. This work opens new avenue for controlling the ion emission in nanoplasmas and can vigorously promote the fields such as development of on-chip beam sources at micro-/nano-scales.