Intriguing steroid glycosides for cancer therapy by suppressing the DNA damage response and mTOR/S6K signaling pathways.

Two rare 8-hydroxysteroid glycosides (6-7), and their downstream metabolites (1-5) with an unprecedented 6/6/5/5/5-pentacyclic scaffold, together with seven known analogues (8-14) were isolated from the twigs and leaves of Strophanthus divaricatus. Their structures were fully assigned by analysis of the spectroscopic and ECD data, NMR calculations, X-ray crystallographic study, and chemical methods. In addition, the inhibitory effects of 1-14 on liver and lung cancer cell lines were evaluated, and preliminary structure-activity relationship was discussed. Data-independent acquisition (DIA)-based quantitative proteomic analysis and biological verification of H1299 cells suggested that this family of compounds may play an anticancer role by suppressing both DNA damage response (DDR) and mTOR/S6K signaling pathways.

Nonlinear Photon Generations from Subwavelength Whispering-Gallery-Mode Resonator.

The strong light localization and long photon lifetimes in whispering gallery mode (WGM) microresonators, benefiting from a high-quality (Q) factor and a small mode volume (V), could significantly enhance light-matter interactions, enabling efficient nonlinear photon generation and paving the way for exploring novel on-chip optical functionalities. However, the leakage of energy from bending losses severely limits the improvement of the Q factor for subwavelength WGM microresonators. Here, we demonstrated an integrated self-suspended WGM microresonator that combines external rings and bridges with a microdisk on a platform of silicon on insulator, achieving about one-hundred-fold enhancement in the Q factor and an ultrasmall mode volume of 2.67(/λnSi)3 as predicted by numerical simulations. We experimentally confirmed the improved performance of the subwavelength WGM resonator with the dramatic enhancement of third-harmonic generation and second-harmonic generation on this device. Our work is anticipated to enhance light-matter interactions on small-footprint microresonators and boost the development of efficient integrated nonlinear and quantum photonics.

Dynamic immune status analysis of peripheral blood mononuclear cells in patients with Klebsiella pneumoniae bloodstream infection sepsis using single-cell RNA sequencing.

Background: Klebsiella pneumoniae is a common Gram-negative bacterium. Blood infection caused by K. pneumoniae is one of the most common causes of human sepsis, which seriously threatens the life of patients. The immune status of peripheral blood mononuclear cells (PBMCs) based on single-cell RNA sequencing (scRNA-seq) in acute stage and recovery stage of sepsis caused by K. pneumoniae bloodstream infection has not been studied. Methods: A total of 13 subjects were included in this study, 3 healthy controls, 7 patients with K. pneumoniae bloodstream infection in the acute stage (4 patients died), and 3 patients in the recovery stage. Peripheral blood of all patients was collected and PBMCs were isolated for scRNA-seq analysis. We studied the changes of PBMCs components, signaling pathways, differential genes, and cytokines in acute and recovery stages. Results: During K. pneumoniae acute infection we observed a decrease in the proportion of T cells, most probably due to apoptosis and the function of T cell subtypes was disorder. The proportion of monocytes increased in acute stage. Although genes related to their phagocytosis function were upregulated, their antigen presentation capacity-associated genes were downregulated. The expression of IL-1ß, IL-18, IFNGR1 and IFNGR2 genes was also increased in monocytes. The proportion of DCs was depleted during the acute stage and did not recover during sepsis recovery. DCs antigen presentation was weakened during the acute stage but recovered fast during the recovery stage. pDCs response to MCP-1 chemokine was weakened, they recovered it quickly during the recovery stage. B cells showed apoptosis both in the acute stage and recovery stage. Their response to complement was weakened, but their antigen presentation function was enhanced. The proportion of NK cells stable during all disease's stages, and the expression of IFN-γ gene was upregulated. Conclusion: The proportion of PBMCs and their immune functions undergo variations throughout the course of the disease, spanning from the acute stage to recovery. These findings provide new insights into the mechanism of PBMCs immune function during K. pneumoniae bloodstream infection sepsis and recovery and sets the basis for further understanding and treatment.

Anti-Inflammatory Salicin Derivatives from the Barks of Salix tetrasperma.

The genus Salix L. is traditionally used in folk medicine to alleviate pain caused by various kinds of inflammation. In the present study, 10 undescribed salicin derivatives along with 5 known congeners were isolated from the barks of Salix tetrasperma, and their structures were elucidated by spectroscopic analyses, single-crystal X-ray diffraction, electronic circular dichroism (ECD) calculations, and chemical conversions. Compounds 4-6 significantly inhibited NO production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages, and the most active 4 obviously suppressed the production of IL-1ß and IL-6 and decreased iNOS and COX-2 expression in a dose-dependent manner. Further Western blotting analysis revealed that the anti-inflammatory mechanism of 4 is possibly mediated through the MAPK and NF-κB signaling pathways.

Monoterpenoid indole alkaloids from Alstonia scholaris and their Toxoplasma gondii inhibitory activity.

Nine previously unreported various types of monoterpenoid indole alkaloids, together with seven known analogues were isolated from the stem barks of Alstonia scholaris through a silica gel free methodology. The structures of 1-9 were elucidated by spectroscopic data analysis, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Compound 1 is a modified echitamine-type alkaloid with a novel 6/5/5/7/6/6 hetero hexacyclic bridged ring system, and 8 and 9 exist as a zwitterion and trifluoroacetate salt, respectively. The anti-Toxoplasma activity of all isolates on infected Vero cells were evaluated, which revealed that compound 14 at 0.24 µM displayed potent activity. This study expanded the structural diversity of alkaloids of A. scholaris, and presented their potential application in anti-Toxoplasma drug development.

Nobachelins, new siderophores from Nocardiopsisbaichengensis protecting Caenorhabditiselegans from Pseudomonasaeruginosa infection.

The biosynthetic potential of actinobacteria to produce novel natural products is still regarded as immense. In this paper, we correlated a cryptic biosynthetic gene cluster to chemical molecules by genome mining and chemical analyses, leading to the discovery of a new group of catecholate-hydroxamate siderophores, nobachelins, from Nocardiopsisbaichengensis DSM 44845. Nobachelin biosynthesis genes are conserved in several bacteria from the family Nocardiopsidaceae. Structurally, nobachelins feature fatty-acylated hydroxy-ornithine and a rare chlorinated catecholate group. Intriguingly, nobachelins rescued Caenorhabditiselegans from Pseudomonasaeruginosa-mediated killing.

Clinical evaluation of metagenomic next-generation sequencing in unbiased pathogen diagnosis of urinary tract infection.

BACKGROUND: Early availability of pathogen identification in urinary tract infections (UTIs) has critical importance in disease management. Metagenomic next-generation sequencing (mNGS) has the potential to transform how acute and serious infections are diagnosed by offering unbiased and culture-free pathogen detection. However, clinical experience with application of the mNGS test is relatively limited. METHODS: We therefore established a MinION-based mNGS pathogens diagnostic platform and evaluated its potential for clinical implementation in UTIs with clinical samples. 213 urine samples from patients with suspected UTIs were included and subjected to mNGS testing using the MinION platform. mNGS results were compared to the gold standard of clinical culture and composite standard of combining clinical testing, confirmatory qPCR testing, and clinical adjudication by doctors. RESULTS: The mNGS exhibited a sensitivity of 81.4% and a specificity of 92.3%, along with a positive predictive value of 96.6%, a negative predictive value of 64.9%, and an overall accuracy of 84.4%, all of which were determined based on the gold standard of routine culture results. When assessed against the composite standard, the sensitivity and specificity both increased to 89.9% and 100%, respectively, while the accuracy rose to 92.4%. Notably, the positive predictive value and negative predictive value also saw improvements, reaching 100% and 76.8%, respectively. Moreover, this diagnostic platform successfully identified dsDNA viruses. Among the 65 culture-negative samples, the viral detection rate reached 33.8% (22/65) and was subsequently validated through qPCR. Furthermore, the automatic bioinformatics pipeline we developed enabled one-click analysis from data to results, leading to a significant reduction in diagnosis time. CONCLUSION: These results demonstrate that the pathogen detection performance of mNGS is sufficient for diagnostic testing in clinical settings. As the method is generally unbiased, it can improve diagnostic testing of UTIs and other microbial infections.

Diagnosis of septic shock by serum measurement of human neutrophil lipocalin by a rapid homogeneous assay.

BACKGROUND: Human neutrophil lipocalin (HNL) is a marker of neutrophil activation and has a high efficacy in diagnosing bacterial infections. In this study, we applied the AlphaLISA technique to measure the serum level of HNL, evaluate HNL's efficacy in diagnosing septic shock, and identify any association between HNL level and septic patients' prognosis. METHODS: We collected 146 serum samples from the Fifth Medical Center of Chinese PLA General Hospital. HNL was measured by AlphaLISA and results were compared with commercial ELISA kits. We studied 78 patients admitted to the ICU with sepsis and data on their clinical and physiological characteristics were recorded. Blood levels of HNL, procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP), and lactate were measured. A receiver operating characteristic (ROC) curve was used to evaluate the performance of each marker. RESULTS: The AlphaLISA assay for serum HNL had a detection range from 1.5 ng/mL to 1000 ng/mL, with a detection limit of 1 ng/mL and a detection time of approximately 25 min. The AlphaLISA assay's results were in high agreement with ELISA results (R2 = 0.9413). HNL levels were analyzed in sepsis patients, and HNL was significantly higher in sepsis patients with shock compared to sepsis patients without shock (median 356.47 ng/mL vs 158.93 ng/mL, P < 0.0001) and in the 28-day non-survivor group compared to the 28-day survivor group (median 331.83 ng/mL vs 175.17 ng/mL, P < 0.0001). ROC curve analysis was performed for the biomarkers. In differentiating the diagnosis of septic shock from sepsis patients, HNL was the most effective marker (AUC = 0.857), followed by PCT (AUC = 0.754) and hs-CRP (AUC = 0.627). In predicting the prognosis of septic patients, lactate had the best effect (AUC = 0.805), followed by HNL (AUC = 0.784), PCT (AUC = 0.721), and hs-CRP (AUC = 0.583). CONCLUSIONS: As an assessment tool, we found that our AlphaLISA had good consistency with an ELISA and had several other advantages, including requiring a shorter processing time and detecting a wider range of serum HNL concentrations. Monitoring serum HNL levels of patients admitted to the ICU might be useful in distinguishing sepsis patients who have septic shock from other sepsis patients, indicating its value in the prediction of sepsis patient prognosis.

An automated detection of epileptic seizures EEG using CNN classifier based on feature fusion with high accuracy.

BACKGROUND: Epilepsy is a neurological disorder that is usually detected by electroencephalogram (EEG) signals. Since manual examination of epilepsy seizures is a laborious and time-consuming process, lots of automatic epilepsy detection algorithms have been proposed. However, most of the available classification algorithms for epilepsy EEG signals adopted a single feature extraction, in turn to result in low classification accuracy. Although a small account of studies have carried out feature fusion, the computational efficiency is reduced due to too many features, because there are also some poor features that interfere with the classification results. METHODS: In order to solve the above problems, an automatic recognition method of epilepsy EEG signals based on feature fusion and selection is proposed in this paper. Firstly, the Approximate Entropy (ApEn), Fuzzy Entropy (FuzzyEn), Sample Entropy (SampEn), and Standard Deviation (STD) mixed features of the subband obtained by the Discrete Wavelet Transform (DWT) decomposition of EEG signals are extracted. Secondly, the random forest algorithm is used for feature selection. Finally, the Convolutional Neural Network (CNN) is used to classify epilepsy EEG signals. RESULTS: The empirical evaluation of the presented algorithm is performed on the benchmark Bonn EEG datasets and New Delhi datasets. In the interictal and ictal classification tasks of Bonn datasets, the proposed model achieves an accuracy of 99.9%, a sensitivity of 100%, a precision of 99.81%, and a specificity of 99.8%. For the interictal-ictal case of New Delhi datasets, the proposed model achieves a classification accuracy of 100%, a sensitivity of 100%, a specificity of 100%, and a precision of 100%. CONCLUSION: The proposed model can effectively realize the high-precision automatic detection and classification of epilepsy EEG signals. This model can provide high-precision automatic detection capability for clinical epilepsy EEG detection. We hope to provide positive implications for the prediction of seizure EEG.

Fpr2 exacerbates Streptococcus suis-induced streptococcal toxic shock-like syndrome via attenuation of neutrophil recruitment.

The life-threatening disease streptococcal toxic shock-like syndrome (STSLS), caused by the bacterial pathogen Streptococcus suis (S. suis). Proinflammatory markers, bacterial load, granulocyte recruitment, and neutrophil extracellular traps (NETs) levels were monitored in wild-type (WT) and Fpr2-/- mice suffering from STSLS. LXA4 and AnxA1, anti-inflammatory mediators related to Fpr2, were used to identity a potential role of the Fpr2 in STSLS development. We also elucidated the function of Fpr2 at different infection sites by comparing the STSLS model with the S. suis-meningitis model. Compared with the WT mice, Fpr2-/- mice exhibited a reduced inflammatory response and bacterial load, and increased neutrophil recruitment. Pretreatment with AnxA1 or LXA4 impaired leukocyte recruitment and increased both bacterial load and inflammatory reactions in WT but not Fpr2-/- mice experiencing STSLS. These results indicated that Fpr2 impairs neutrophil recruitment during STSLS, and this impairment is enhanced by AnxA1 or LXA4. By comparing the functions of Fpr2 in different S. suis infection models, inflammation and NETs was found to hinder bacterial clearance in S. suis meningitis, and conversely accelerate bacterial clearance in STSLS. Therefore, interference with neutrophil recruitment could potentially be harnessed to develop new treatments for this infectious disease.

Detection of Pathogens and Antimicrobial Resistance Genes in Ventilator-Associated Pneumonia by Metagenomic Next-Generation Sequencing Approach.

Background: The early identification of pathogens and their antibiotic resistance are essential for the management and treatment of patients affected by ventilator-associated pneumonia (VAP). However, microbiological culture may be time-consuming and has a limited culturability of many potential pathogens. In this study, we developed a rapid nanopore-based metagenomic next-generation sequencing (mNGS) diagnostic assay for detection of VAP pathogens and antimicrobial resistance genes (ARGs). Patients and Methods: Endotracheal aspirate (ETA) samples from 63 patients with suspected VAP were collected between November 2021 and July 2022. Receiver operating characteristic (ROC) curves were established to compare the pathogen identification performance of the target pathogen reads, reads percent of microbes (RPM) and relative abundance (RA). The evaluation of the accuracy of mNGS was performed comparing with the gold standard and the composite standard, respectively. Then, the ARGs were analyzed by mNGS. Results: ROC curves showed that RA has the highest diagnostic value and the corresponding threshold was 9.93%. The sensitivity and specificity of mNGS test were 91.3% and 78.3%, respectively, based on the gold standard, while the sensitivity and specificity of mNGS test were 97.4% and 100%, respectively, based on the composite standard. A total of 13 patients were virus-positive based on mNGS results, while the coinfection rate increased from 27% to 46% compared to the rate obtained based on clinical findings. The mNGS test also performed well at predicting antimicrobial resistance phenotypes. Patients with a late-onset VAP had a significantly greater proportion of ARGs in their respiratory microbiome compared to those with early-onset VAP (P = 0.041). Moreover, the median turnaround time of mNGS was 4.43 h, while routine culture was 72.00 h. Conclusion: In this study, we developed a workflow that can accurately detect VAP pathogens and enable prediction of antimicrobial resistance phenotypes within 5 h of sample receipt by mNGS.

Low-threshold nanolasers based on miniaturized bound states in the continuum.

The pursuit of compact lasers with low thresholds has imposed strict requirements on tight light confinements with minimized radiation losses. Bound states in the continuum (BICs) have been recently demonstrated as an effective mechanism to trap light. However, most reported BIC lasers are still bulky due to the absence of in-plane light confinement. Here, we combine BICs and photonic bandgaps to realize three-dimensional light confinements, as referred to miniaturized BICs (mini-BICs). We demonstrate highly compact active mini-BIC resonators with a record high-quality (Q) factor of up to 32,500, which enables single-mode lasing with the lowest threshold of 80 W/cm2 among the reported BIC lasers. In addition, photon statistics measurements further confirm the occurrence of the stimulated emission in our devices. Our work reveals a path toward compact BIC lasers with ultralow power consumption and potentially boosts the applications in cavity quantum electrodynamics, nonlinear optics, and integrated photonics.

Manipulating cavity photon dynamics by topologically curved space.

Asymmetric microcavities supporting Whispering-gallery modes (WGMs) are of great significance for on-chip optical information processing. We establish asymmetric microcavities on topologically curved surfaces, where the geodesic light trajectories completely reconstruct the cavity mode features. The curvature-mediated photon-lifetime engineering enables the enhancement of the quality factors of periodic island modes by up to 200 times. Strong and weak coupling between modes of very different origins occurs when the space curvature brings them into resonance, leading to fine tailoring of the cavity photon energy and lifetime and the observation of non-Hermitian exceptional point (EP). At large space curvatures, the role of the WGMs is replaced by high-Q periodic modes protected by the high stability of island-like light trajectory. Our work demonstrates interesting physical mechanisms at the crosspoint of optical chaotic dynamics, non-Hermitian physics, and geodesic optical devices, and would initiate the novel area of geodesic microcavity photonics.

ROS-cleavable diselenide nanomedicine for NIR-controlled drug release and on-demand synergistic chemo-photodynamic therapy.

Many chemotherapeutic drugs and photosensitizers suffer from poor solubility, unspecific delivery and uncontrollable release, which severely impede their biomedical applications. Herein, we designed a type of ROS-cleavable hydrophilic diselenide nanoparticles through self-assembling of PEG-modified camptothecin (CPT, a hydrophobic drug) and meso­tetra (4-carboxyphenyl) porphine (TCPP, a hydrophobic photosensitizer). The TCPP@SeSe-CPT nanomedicine (particle size: 116.5 ± 1.9 nm) has stability for long-time blood circulation. Near-infrared (NIR) laser-triggered generation of ROS from TCPP can efficiently break the ROS-sensitive diselenide bond, which induces the decomposition of TCPP@SeSe-CPT nanomedicine for concurrent release of CPT and TCPP. Moreover, the released amounts of CPT and TCPP can be regulated by adjusting the NIR laser irradiation time. Such NIR-controlled release of CPT and TCPP can give rise to on-demand synergistic chemo-/photodynamic therapeutic effects for maximized tumor growth suppression with minimized side effects. STATEMENT OF SIGNIFICANCE: In this work, a ROS-cleavable diselenide nanoparticle was designed and successfully self-assembled with the hydrophobic drug camptothecin and photosensitizer TCPP into a hydrophilic TCPP@SeSe-CPT nanomedicine. Compared with traditional drug delivery systems, TCPP@SeSe-CPT nanomicelles could reduce premature drug release and co-deliver hydrophobic chemotherapeutic drugs/photosensitizers to tumors, which yielded a NIR-controlled synergistic chemo-/photodynamic therapeutic effect. Since diselenide bond is more sensitive than the traditional disulfide bond, under the 660 nm laser irradiation (300 mW/cm2), ROS generated from laser-excited TCPP in TCPP@SeSe-CPT nanomicelles could break the diselenium bonds to achieve the light-controlled release of CPT. In addition, the photosensitizer TCPP could also be imaged at the tumor site. Due to the photodynamic therapy from laser-excited TCPP and chemotherapy from photocontrolled release of CPT in TCPP@SeSe-CPT, our designed nanomicelles yielded potent antitumor effects both in vitro and in vivo.

Comparison Analysis of Different DNA Extraction Methods on Suitability for Long-Read Metagenomic Nanopore Sequencing.

Metagenomic next-generation sequencing (mNGS) is a novel useful strategy that is increasingly used for pathogens detection in clinic. Some emerging mNGS technologies with long-read ability are useful to decrease sequencing time and increase diagnosed accuracy, which is of great significance in rapid pathogen diagnosis. Reliable DNA extraction is considered critical for the success of sequencing; hence, there is thus an urgent need of gentle DNA extraction method to get unbiased and more integrate DNA from all kinds of pathogens. In this study, we systematically compared three DNA extraction methods (enzymatic cell lysis based on MetaPolyzyme, mechanical cell lysis based on bead beating, and the control method without pre-cell lysis, respectively) by assessing DNA yield, integrity, and the microbial diversity based on long-read nanopore sequencing of urine samples with microbial infections. Compared with the control method, the enzymatic-based method increased the average length of microbial reads by a median of 2.1-fold [Inter Quartile Range (IQR), 1.7-2.5; maximum, 4.8) in 18 of the 20 samples and the mapped reads proportion of specific species by a median of 11.8-fold (Inter Quartile Range (IQR), 6.9-32.2; maximum, 79.27]. Moreover, it provided fully (20 of 20) consistent diagnosed results to the clinical culture and more representative microbial profiles (P < 0.05), which all strongly proves the excellent performance of enzymatic-based method in long-read mNGS-based pathogen identification and potential diseases diagnosis of microbiome related.

Rapid Detection of Bacterial Pathogens and Antimicrobial Resistance Genes in Clinical Urine Samples With Urinary Tract Infection by Metagenomic Nanopore Sequencing.

Urinary tract infections (UTIs) are among the most common acquired bacterial infections in humans. The current gold standard method for identification of uropathogens in clinical laboratories is cultivation. However, culture-based assays have substantial drawbacks, including long turnaround time and limited culturability of many potential pathogens. Nanopore sequencing technology can overcome these limitations and detect pathogens while also providing reliable predictions of drug susceptibility in clinical samples. Here, we optimized a metagenomic nanopore sequencing (mNPS) test for pathogen detection and identification in urine samples of 76 patients with acute uncomplicated UTIs. We first used twenty of these samples to show that library preparation by the PCR Barcoding Kit (PBK) led to the highest agreement of positive results with gold standard clinical culture tests, and enabled antibiotic resistance detection in downstream analyses. We then compared the detection results of mNPS with those of culture-based diagnostics and found that mNPS sensitivity and specificity of detection were 86.7% [95% confidence interval (CI), 73.5-94.1%] and 96.8% (95% CI, 82.4-99.9%), respectively, indicating that the mNPS method is a valid approach for rapid and specific detection of UTI pathogens. The mNPS results also performed well at predicting antibiotic susceptibility phenotypes. These results demonstrate that our workflow can accurately diagnose UTI-causative pathogens and enable successful prediction of drug-resistant phenotypes within 6 h of sample receipt. Rapid mNPS testing is thus a promising clinical diagnostic tool for infectious diseases, based on clinical urine samples from UTI patients, and shows considerable potential for application in other clinical infections.

Suilyin Disrupts the Blood-Brain Barrier by Activating Group III Secretory Phospholipase A2.

Serious diseases caused by Streptococcus suis serotype 2 (S. suis 2) include septicaemia and meningitis, which are associated with high morbidity and mortality. Proliferation in the blood can result in a breach of the blood-brain barrier (BBB) and provide entry into the cerebrospinal fluid (CSF), where bacteria cause inflammation of the meningeal membranes resulting in meningitis. The molecular mechanisms of how this pathogen crosses the BBB remain unclear. Suilysin (SLY) has been identified as an important secreted virulence factor of S. suis 2 and may play a vital role in provoking meningitis. In this investigation, we demonstrate that SLY can increase the paracellular permeability of BBB, both in vivo and in vitro, via the activation of group III secretory phospholipase A2 (PLA2G3). Our results indicate that at lower, sublytic concentrations, the toxin can stimulate cerebral microvascular endothelial cells to release TNF-α, thereby inducing high level expressions of PLA2G3. Abnormal elevations of PLA2G3 might further injure tissues through direct cytolytic effectors or other responses.

Highly efficient nonlinear optical emission from a subwavelength crystalline silicon cuboid mediated by supercavity mode.

The low quantum efficiency of silicon (Si) has been a long-standing challenge for scientists. Although improvement of quantum efficiency has been achieved in porous Si or Si quantum dots, highly efficient Si-based light sources prepared by using the current fabrication technooloy of Si chips are still being pursued. Here, we proposed a strategy, which exploits the intrinsic excitation of carriers at high temperatures, to modify the carrier dynamics in Si nanoparticles. We designed a Si/SiO2 cuboid supporting a quasi-bound state in the continuum (quasi-BIC) and demonstrated the injection of dense electron-hole plasma via two-photon-induced absorption by resonantly exciting the quasi-BIC with femtosecond laser pulses. We observed a significant improvement in quantum efficiency by six orders of magnitude to ~13%, which is manifested in the ultra-bright hot electron luminescence emitted from the Si/SiO2 cuboid. We revealed that femtosecond laser light with transverse electric polarization (i.e., the electric field perpendicular to the length of a Si/SiO2 cuboid) is more efficient for generating hot electron luminescence in Si/SiO2 cuboids as compared with that of transverse magnetic polarization (i.e., the magnetic field perpendicular to the length of a Si/SiO2 cuboid). Our findings pave the way for realizing on-chip nanoscale Si light sources for photonic integrated circuits and open a new avenue for manipulating the luminescence properties of semiconductors with indirect bandgaps.

Diterpenoids from Sauropus spatulifolius Leaves with Antimicrobial Activities.

As a plant used in both food and medicine, Sauropus spatulifolius is consumed widely as a natural herbal tea, food source, and Chinese medicine. Inspired by its extensive applications, we conducted a systematic phytochemical study of the leaves of S. spatulifolius. Thirteen new diterpenoids, sauspatulifols A-M (1-13), including four ent-cleistanthane-type diterpenoids (1-4), eight 15,16-di-nor-ent-cleistanthane-type diterpenoids (5-12), and one 17-nor-ent-pimarane-type diterpenoid (13) as well as one known diterpenoid, cleistanthol (14), were isolated. All of these diterpenoids feature a 2α,3α-dihydroxy unit within the A ring, and their structures were elucidated by spectroscopic data analysis, electronic circular dichroism calculations, and single-crystal X-ray diffraction analysis. Compound 14 displayed moderate inhibitory activity against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, and Shigella flexneri with the same minimum inhibitory concentration value of 12 µg/mL as well as activity against vesicular stomatitis virus and influenza A virus.