Multi-omics analysis identifies sex-specific hepatic protein-metabolite networks in yellow catfish (Pelteobagrus fulvidraco) exposed to chronic hypoxia

Hypoxia disrupts the endocrine system of teleosts. The liver plays important roles in the endocrine system, energy storage, and metabolic processes. The aim of this study was to investigate the sex-specific hepatic response of yellow catfish under chronic hypoxia at the multi-omics level. Common hepatic responses in both sexes included the HIF-1 signaling pathway, glycolysis/gluconeogenesis, and steroid biosynthesis. Hypoxia dysregulated primary bile acid biosynthesis, lipid metabolism, and vitellogenin levels in female fish. Endoplasmic reticulum function in females also tended to be disrupted by hypoxia, as evidenced by significantly enriched pathways, including ribosome, protein processing in the endoplasmic reticulum, and RNA degradation. Other pathways, including the TCA cycle, oxidative phosphorylation, and Parkinson's and Huntington's disease, were highly enriched by hypoxia in male fish, suggesting that mitochondrial function was dysregulated. In both sexes of yellow catfish, the cell cycle was arrested and apoptosis was inhibited under chronic hypoxia. Multi-omics suggested that SLC2A5, CD209, LGMN, and NEDD8 served as sex-specific markers in these fish under chronic hypoxia. Our results provide insights into hepatic adaptation to chronic hypoxia and facilitate our understanding of sex-specific responses in fish.

The application of extracorporeal shock wave therapy in the treatment of temporomandibular joint disorders in a preliminary, small sample study

OBJECTIVE

The aim of this study was to investigate the efficacy of low-intensity, high-frequency shock waves in the treatment of temporomandibular joint disorders.

METHODS

Twenty-six patients with temporomandibular joint disorder admitted to the Second Hospital of Shanxi Medical University from August 2022 to December 2022 were selected as study subjects and randomly divided into two groups, A and B, with 13 patients each. In Group A, there were 5 males and 8 females with an average age of 38.85 ± 11.03 years. In Group B, there were 4 males and 9 females with an average age of 39.15 ± 11.16 years. Group A was the control group, which received routine treatment (manual massage + transcutaneous electrical nerve stimulation + ultrashort wave therapy) plus sham shock wave therapy; Group B was the experimental group, which received routine treatment (manual massage + transcutaneous electrical nerve stimulation + ultrashort wave therapy) plus shock wave therapy. The routine treatment was administered once/day, five times per week for a total of 2 weeks of treatment. In addition, shock wave therapy was administered once every 5 days, and the treatment was administered three times. The treatment period was 2 weeks, and the two groups were compared before treatment, at the end of the treatment period, and 4 weeks after treatment. The pain level of the two groups was assessed by the visual analogue scale (VAS) before and after treatment, and the temporomandibular opening index (TOI) before and after treatment was compared between the two groups. VAS and TOI scores were evaluated using the Mann-Whitney U-test, the Kruskal-Wallis H-test and two-way ANOVA.

RESULTS

There was no significant difference in the VAS score and temporomandibular opening index between the two groups before treatment (p = .829 and .75, respectively). After 2 weeks of treatment, the VAS score and temporomandibular joint opening index of both groups were significantly improved compared to those before therapy. In addition, the VAS score and temporomandibular joint opening index in the experimental group were significantly better than those in the control group (p < .001 and <.001, respectively). There was a small increase in scores 4 weeks after the treatment compared to just after the treatment period, but the difference was not significant.

CONCLUSION

This is a preliminary small sample study that demonstrates the positive effect of using low-intensity, high-frequency shock waves on the treatment of temporomandibular joint disorders and is worthy of clinical promotion.

CircUBE3A(2,3,4,5) promotes adenylate-uridylate-rich binding factor 1 nuclear translocation to suppress prostate cancer metastasis

Metastatic progression is the primary cause of mortality in prostate cancer (PCa) patients. Although circular RNAs (circRNAs) have been implicated in cancer progression and metastasis, our current understanding of their role in PCa metastasis remains limited. In this study, we identified that circUBE3A(2,3,4,5), which originated from exons 2, 3, 4 and 5 of the human ubiquitin-protein ligase E3A (UBE3A) gene, was specifically downregulated in PCa tissues and correlated with the Gleason score, bone metastasis, and D'Amico risk classification. Through the in vitro and in vivo experiments, we demonstrated that overexpression of circUBE3A(2,3,4,5) inhibited PCa cell migration, invasion, metastasis, and proliferation. Mechanistically, circUBE3A(2,3,4,5) was found to bind to adenylate-uridylate-rich binding factor 1 (AUF1), promoting the translocation of AUF1 into the nucleus. This led to decreased AUF1 in the cytoplasm, resulting in methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) mRNA instability and a subsequent reduction at the protein level. The downregulation of MTHFD2 further inhibited vimentin expression, thereby suppressing PCa cell epithelial-mesenchymal transition. Additionally, two pairs of the short-inverted repeats (TSIRs) in flanking introns were identified to synergistically facilitate the generation of circUBE3A(2,3,4,5) and other circRNAs. In summary, TSIRs-induced circUBE3A(2,3,4,5) acts as a suppressor of PCa metastasis by enhancing AUF1 nuclear translocation, reducing MTHFD2, and subsequently inhibiting vimentin expression. This study characterizes circUBE3A(2,3,4,5) as a functional circRNA and proposes it as a highly promising target for preventing PCa metastasis.

ACE-2-like enzymatic activity is associated with immunoglobulin in COVID-19 patients

Many mechanisms responsible for COVID-19 pathogenesis are well-established, but COVID-19 includes features with unclear pathogenesis, such as autonomic dysregulation, coagulopathies, and high levels of inflammation. The receptor for the SARS-CoV-2 spike protein receptor-binding domain (RBD) is angiotensin-converting enzyme 2 (ACE2). We hypothesized that some COVID-19 patients may develop antibodies that have a negative molecular image of RBD sufficiently similar to ACE2 to yield ACE2-like catalytic activity-ACE2-like abzymes. To explore this hypothesis, we studied patients hospitalized with COVID-19 who had plasma samples available obtained about 7 days after admission. ACE2 is a metalloprotease that requires Zn2+ for activity. However, we found that the plasma from some patients studied could specifically cleave a synthetic ACE2 peptide substrate, even though the plasma samples were collected using disodium EDTA anticoagulant. When we spiked plasma with synthetic ACE2, no ACE2 substrate cleavage activity was observed unless Zn2+ was added or the plasma was diluted to decrease EDTA concentration. After processing samples by 100 kDa size exclusion columns and protein A/G adsorption, which depleted immunoglobulin by >99.99%, the plasma samples did not cleave the ACE2 substrate peptide. The data suggest that some patients with COVID-19 develop antibodies with abzyme-like activity capable of cleaving synthetic ACE2 substrate. Since abzymes can exhibit promiscuous substrate specificities compared to the enzyme whose active site image they resemble, and since proteolytic cascades regulate many physiologic processes, anti-RBD abzymes may contribute to some otherwise obscure COVID-19 pathogenesis.

IMPORTANCE

We provide what we believe to be the first description of angiotensin-converting enzyme 2 (ACE2)-like enzymatic activity associated with immunoglobulin in COVID-19 patients. COVID-19 includes many puzzling clinical features that have unclear pathogenesis, including a hyperinflammatory state, abnormalities of the clotting cascade, and blood pressure instability. We hypothesized that some patients with COVID-19 patients may produce antibodies against SARS-CoV-2 with enzymatic activity, or abzymes, that target important proteolytic regulatory cascades. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein binds ACE2 on the surface of the future host cell. This means that the RBD has a negative molecular image of ACE2. We hypothesized that some antibodies produced against the RBD would have, in turn, a negative molecular image of the RBD sufficiently similar to ACE2 to have ACE2-like catalytic activity. In other words, some anti-RBD antibodies would be ACE2-like abzymes. Abzymes elicited by SARS-CoV-2 infection have the potential to affect host physiology.

Anillin contributes to prostate cancer progression through the regulation of IGF2BP1 to promote c-Myc and MAPK signaling

Prostate cancer (PCa), especially castration-resistant PCa, is a common and fatal disease. Anillin (ANLN) is an actin-binding protein that is involved in various malignancies, including PCa. However, the regulatory mechanism of ANLN in PCa remains unclear. Exploring the role of ANLN in PCa development and discovering novel therapeutic targets are crucial for PCa therapy. In the current work, we discovered that ANLN expression was considerably elevated in PCa tissues and cell lines when compared to nearby noncancerous prostate tissues and normal prostate epithelial cells. ANLN was associated with more advanced T stage, N stage, higher Gleason score, and prostate-specific antigen (PSA) level. In addition, we discovered that overexpression of ANLN promoted PCa cell proliferation, migration, and invasion in vitro and in vivo. Mechanistically, we performed RNA-seq to identify the regulatory influence of ANLN on the MAPK signal pathway. Furthermore, a favorable association between ANLN expression and IGF2BP1 expression was identified. The tumor-suppressive impact of ANLN downregulation on PCa cell growth was partially reversed by overexpressing IGF2BP1. Meanwhile, we discovered that ANLN can stabilize the proto-oncogene c-Myc and activate the MAPK signaling pathway through IGF2BP1. These findings indicate that ANLN could be a potential therapeutic target in PCa.

Vaccine Strategies to Elicit Mucosal Immunity

Vaccines are essential tools to prevent infection and control transmission of infectious diseases that threaten public health. Most infectious agents enter their hosts across mucosal surfaces, which make up key first lines of host defense against pathogens. Mucosal immune responses play critical roles in host immune defense to provide durable and better recall responses. Substantial attention has been focused on developing effective mucosal vaccines to elicit robust localized and systemic immune responses by administration via mucosal routes. Mucosal vaccines that elicit effective immune responses yield protection superior to parenterally delivered vaccines. Beyond their valuable immunogenicity, mucosal vaccines can be less expensive and easier to administer without a need for injection materials and more highly trained personnel. However, developing effective mucosal vaccines faces many challenges, and much effort has been directed at their development. In this article, we review the history of mucosal vaccine development and present an overview of mucosal compartment biology and the roles that mucosal immunity plays in defending against infection, knowledge that has helped inform mucosal vaccine development. We explore new progress in mucosal vaccine design and optimization and novel approaches created to improve the efficacy and safety of mucosal vaccines.

[Thoughts and suggestions on digital services to enhance the level of vaccination management]

With the development of information technology and the increasing demand for vaccination services among the people, it is a definite trend to enhance the quality of vaccination services through digitization. This article starts with a clear concept of digital services for vaccination, introduces the current development status in China and abroad, analyzes the advantages and disadvantages of existing models in leading regions, takes a glean from the summation, and proposes targeted solutions. This study suggests establishing a departmental coordination mechanism for data interconnection and sharing, formulating data standards and functional specifications, enhancing the functionalities of the immunization planning information system, strengthening data collection and analytical usage, and intensifying appointment management and science and health education to provide expert guidance for the construction of digital vaccination services across the country in the future.

Effects of carbamazepine on BDNF expression in trigeminal ganglia and serum in rats with trigeminal neuralgia

OBJECTIVES

Trigeminal neuralgia (TN) is a severe chronic neuropathic pain that mainly affects the distribution area of the trigeminal nerve with limited treating efficacy. There are numerous treatments for TN, but currently the main clinical approach is to suppress pain by carbamazepine (CBZ). Brain-derived neurotrophic factor (BDNF) is closely related to chronic pain. This study aims to determine the effects of CBZ treatment on BDNF expression in both the trigeminal ganglion (TG) and serum of TN via a chronic constriction injury of the infraorbital nerve (ION-CCI) rat model.

METHODS

The ION-CCI models were established in male Sprague-Dawley rats and were randomly divided into a sham group, a TN group, a TN+low-dose CBZ treatment group (TN+20 mg/kg CBZ group), a TN+medium-dose CBZ treatment group (TN+40 mg/kg CBZ group), and a TN+high-dose CBZ treatment group (TN+80 mg/kg CBZ group). The mechanical pain threshold in each group of rats was measured regularly before and after surgery. The expressions of BDNF and tyrosine kinase receptor B (TrkB) mRNA in TGs of rats in different groups were determined by real-time PCR, and the expression of BDNF protein on neurons in TGs was observed by immunofluorescence. Western Blotting was used to detect the protein expression of BDNF, TrkB, extracellular regulated protein kinases (ERK), and phospho-extracellular regulated protein kinases (p-ERK) in TGs of rats in different groups. The expression of BDNF in the serum of rats in different groups was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results of mechanical pain sensitivity showed that there was no significant difference in the mechanical pain threshold in the right facial sensory area of the experimental rats in each group before surgery (all P>0.05). From the 3rd day after operation, the mechanical pain threshold of rats in the TN group was significantly lower than that in the sham group (all P<0.01), and the mechanical pain threshold of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 CBZ mg/kg group was higher than that in the TN group (all P<0.05). The BDNF and TrkB mRNA and protein expressions in TGs of rats in the TN group were higher than those in the sham group (all P<0.05), and those in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than the TN group (all P<0.05). The p-ERK levels in TG of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were significantly decreased compared with the TN group (all P<0.05). The BDNF and neuron-specific nuclear protein (NeuN) were mainly co-expressed in neuron of TGs in the TN group and they were significantly higher than those in the sham group (all P<0.05). The co-labeled expressions of BDNF and NeuN in TGs of the TN+ 80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). The results of ELISA showed that the level of BDNF in the serum of the TN group was significantly higher than that in the sham group (P<0.05). The levels of BDNF in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). Spearman correlation analysis showed that the BDNF level in serum was negatively correlated with mechanical pain threshold (r=-0.650, P<0.01).

CONCLUSIONS

CBZ treatment can inhibit the expression of BDNF and TrkB in the TGs of TN rats, reduce the level of BDNF in serum of TN rats and the phosphorylation of ERK signaling pathway, so as to inhibit TN. The serum level of BDNF can be considered as an indicator for the diagnosis and prognosis of TN.

A randomized trial of treatment for anterior cruciate ligament reconstruction by radial extracorporeal shock wave therapy

OBJECTIVE

The aim of this study was to explore the effects of radial extracorporeal shock wave therapy (rESWT) in patients with anterior cruciate ligament(ACL) reconstruction(ACLR).

METHODS

We conducted a randomized, controlled trial involving 72 eligible patients with ACL reconstruction in which we compared two strategies: the experimental group was standard rehabilitation plus rESWT and the control group was standard rehabilitation plus sham rESWT. The outcome was the change from baseline to 24 weeks in the average score on Lysholm knee joint score (LKS), range of motion (ROM), visual analogue scale (VAS) and International Knee Literature Committee (IKDC).

RESULTS

Of 36 subjects assigned to rehabilitation plus rESWT, 4 lost to follow up. Of 36 assigned to rehabilitation plus sham rESWT, 5 lost to follow up. The LKS, ROM and IKDC scores of the experimental group were markedly increased at 3 and 6 weeks after treatment (P < 0.001), and the VAS was notably decreased (P < 0.001). However, there were no significant differences in the LKS, ROM, IKDC and VAS between the groups at 24 weeks after treatment (P > 0.05).

CONCLUSION

The strategy of rehabilitation plus rESWT had better functional outcomes after ACL reconstruction. As such, our study demonstrates that rESWT is essential for patients with ACL reconstruction. Early use of rESWT can improve joint function, pain relief and ability of daily living. rESWT has a positive effect on the overall rehabilitation of patients.

Novel Optical Kerr Switching Photonic Device Based on Nonlinear Carbon Material

In the context of current communication systems, there is an urgent demand for more efficient and higher-speed optical signal processing technologies. Researchers are actively exploring new materials and devices to harness nonlinear optical phenomena, seeking advancements in this field. Nonlinear carbon materials, especially promising 2D materials, have garnered attention for their potential interaction with light and have become integral to the development of all-optical signal processing devices. This study focuses on utilizing a photonic device based on a nonlinear Au/CB composite material for optical Kerr switching. The application of Au/CB as a nonlinear material in the Kerr switch represents a noteworthy advancement, demonstrating its capability to modulate optical signals. By appropriately applying a pump light, the study achieves optical Kerr switching with an extinction ratio of approximately 15 dB in the fully off state of the signal light carrying a 10 GHz analog signal, marking a pioneering achievement in the field to the best of our knowledge. The experimental results, encompassing extinction ratios, signal control, and stability, not only validate the feasibility of this technology but also underscore its potential applicability within optical communication systems. The successful modulation and control of a 10 GHz analog signal showcase the practicality and effectiveness of the Au/CB-based optical Kerr switch. This progress contributes to the continuous evolution of optical Kerr switching, a crucial component in modern optical communication systems. Therefore, we believe that the Au/CB-based optical Kerr switch is an exceptionally promising and stable all-optical signal processing device. As the contemporary communication landscape evolves, the integration of this technology holds the potential to enhance the efficiency and speed of optical signal processing.

[Current status of vaccination services for adults in urban and rural areas of nine provinces in China from 2019 to 2021]

Objective: To understand the current situation of vaccination services for adults in China, explore how to establish a stable and efficient vaccination service system for adults, and provide reference for formulating corresponding policies. Methods: The vaccination information systems of nine provinces in China were used to obtain information on urban and rural vaccination of influenza vaccine, 23-valent pneumococcal polysaccharide vaccine (PPV23), and human papillomavirus vaccine (HPV) from 2019 to 2021. The indicator, vaccination rate/full vaccination rate, was used for statistical description. Results: The vaccination rate/full vaccination rate of the three vaccines in eastern China was generally higher than that in central and western China. The vaccination rate/full vaccination rate in urban areas was generally higher than that in rural areas. From 2019 to 2021, the vaccination rates of influenza vaccine among people aged 60 years and above in urban and rural areas were 2.96%, 6.29%, 6.14% and 1.29%, 2.58%, 2.94%, respectively. The vaccination rates of the PPV23 among people aged 60 years and above in urban and rural areas increased year by year, with rates of 0.38%, 1.05%, 1.15% and 0.14%, 0.49%, 0.59%, respectively. From 2019 to 2021, the HPV coverage of female adults aged 27-45 years in urban and rural areas increased year by year, with rates of 0.46%, 0.93%, 1.88% and 0.17%, 0.40%, 1.08%, respectively. Conclusion: The vaccination rates of influenza vaccine,PPV23 vaccine and HPV vaccine for adults in China are relatively low, with higher rates in the eastern region than in the central and western regions, and higher rates in urban areas than in rural areas. It is recommended to formulate corresponding health and economic policies and explore a suitable vaccination service system for adults in China to improve vaccination rates.

[Considerations for the development of adult vaccination in China]

Adult vaccination is an important component of the life-course immunization for all. Strengthening adult vaccination in China contributes to shrinking immunization gaps between regions and groups, enhancing the overall immunity of our population, and promoting health equity and social prosperity. Chinese adults bear the heavy burden of vaccine preventable diseases such as influenza, pneumococcal diseases and shingles, and have low coverage of vaccines against those diseases, so it is necessary to make efforts to improve adult vaccination development. This article focuses on elaborating the values of adult vaccination, introducing the current status of adult vaccination abroad, and analyzing the challenges and existing foundations for China to provide adult vaccination, and makes suggestions for the building and development of adult vaccination.

Construction and evaluation of a novel prognostic risk model of aging-related genes in bladder cancer

Background

Bladder cancer (BLCA) is the most common malignancy of the urinary system. Muscle-invasive bladder cancer (MIBC), which constitutes approximately 25% of all BLCA cases, is characterized by frequent recurrence and early onset of metastasis. Bladder cancer most commonly occurs in elderly patients and is significantly associated with aging. However, the prognostic value of age-related genes in BLCA, especially in MIBC, remains unclear.

Materials and methods

Training and testing sets were obtained from The Cancer Genome Atlas BLCA project. Differentially expressed genes between BLCA and normal samples intersected with human aging-related genes. Univariate Cox regression and least absolute shrinkage and selection operator regression analyses were used to identify prognostic aging-related signatures, followed by the construction of a risk score model and nomogram. Kaplan-Meier and receiver operating characteristic analyses were conducted to assess the predictive power. An independent BLCA cohort of 165 samples was included for external validation. The CIBERSORT algorithm was used to explore the characteristics of the immune microenvironment.

Results

Seven genes (IGF1, NGF, GCLM, PYCR1, EFEMP1, APOC3, and IFNB1) were identified by Cox and least absolute shrinkage and selection operator analyses. After combining the gene signature with the clinical parameters of patients with BLCA, a risk-prognosis model and nomogram were constructed and validated with the testing set. Bladder cancer cases with high 7-gene signature scores (high-risk group) and low scores (low-risk group) showed distinct prognoses. Furthermore, 7 types of immune cells were significantly altered between the low- and high-risk groups.

Conclusions

Collectively, our data provide a 7-gene signature that serves as a potential biomarker for BLCA, especially MIBC. Moreover, this 7-gene signature highlights the role of the tumor immune microenvironment in prognosis and thus might be related to the response to anti-programmed cell death protein 1-based immunotherapy.

Information Leakage Rate of Optical Code Division Multiple Access Network Using Wiretap Code

Secrecy capacity is usually employed as the performance metric of the physical layer security in fiber-optic wiretap channels. However, secrecy capacity can only qualitatively evaluate the physical layer security, and it cannot quantitatively evaluate the physical layer security of an imperfect security system. Furthermore, secrecy capacity cannot quantitatively evaluate the amount of information leakage to the eavesdropper. Based on the channel model of an optical CDMA network using wiretap code, the information leakage rate is analyzed to evaluate the physical layer security. The numerical results show that the information leakage rate can quantitatively evaluate the physical layer security of an optical CDMA wiretap channel, and it is related to transmission distance, eavesdropping position, confidential information rate and optical code.

Distributed optical synthetic aperture position-transformed method with high-frequency domain coverage

Realizing an ultrahigh-equivalent aperture for space-based direct optical detection using a distributed optical synthetic aperture (DOSA) system with a very low filling ratio is challenging. This study proposes a position-transformation method for DOSA systems with high-frequency domain coverage called High-Frequency domain-Covering discrete Archimedean Spiral Arrays (HFCASA). The study shows that Golay3 HFCASA with a filling ratio of 0.0675% can greatly improve frequency domain coverage and fulfill the resolution requirements of a 200 m aperture telescope. HFCASA provides the theoretical basis for the future deep-space exploration of DOSA.

TiN/Ti3C2 heterojunction-based photonic device for optical Kerr switch

As one of the new nanomaterials, TiN/Ti3C2 shows excellent optoelectronic characteristics, thus it has been widely used in many applications, such as biomedicine, optical sensors, image processing, and optical switching. With the advancement of communication capabilities and communication networks, optical fiber communication has put a higher demand on signal processing. In order to overcome the limitations of the electronic transfer rate bottleneck, the concept of all-optical signal processing has been proposed. Utilizing the excellent optical nonlinear effect of the TiN/Ti3C2 heterojunction-coated microfiber (THM), a novel THM-based optical Kerr switch has been proposed. Injecting a strong control light and a signal light into the device simultaneously, and controlling the state of turn on or off of the control light, can adjust the intensity of the signal light. Based on this, the amplitude modulation of the signal light can be achieved. With a control light power of 200 mW, the maximum extinction ratio of the signal light reaches 27 dB. We believe that this type of compact device can demonstrate great potential for integration with current high-speed fiber communication networks, providing a possible method for all-optical signal processing through nonlinear effects, and has broad prospects in the field of all-optical signal processing, robots, and high-speed communication.

Distribution and Prediction of Incremental Cutter Flank Wear in High-Efficiency Milling

In the milling of titanium alloy workpieces, tool wear seriously affects the surface quality of a workpiece and its tool life. It is of great significance to study the influence of instantaneous contact stiffness on instantaneous friction variables and incremental wear, which is of great significance for the realization of control over the degree of flank wear and improving the service life of cutter teeth. In this paper, an experiment to monitor cutting with a Ti6Al4V workpiece with a high-feed milling cutter was carried out; according to the experimental results, the wear area of the flank face of the cutter tooth was determined. The feature points of the flank were selected, and an instantaneous contact stiffness calculation method for the flank was proposed. The infinitesimal method was used to characterize the distribution of the contact stiffness of the flank, and the evolution characteristics of instantaneous contact stiffness distribution under the influence of vibration were obtained. According to the calculation results, the instantaneous distribution of flank wear depth was calculated. A grey correlation degree was used to reveal the correlation between the instantaneous contact stiffness of the flank face and wear depth, and a positionable wear-prediction model based on the instantaneous contact stiffness of the flank was proposed. Based on a BPNN (back propagation neural network), a prediction model for flank wear was established. The results showed that the above model and method could accurately predict the instantaneous wear of the tool flank.

Glutaraldehyde-crosslinked Rhizopus oryzae whole cells show improved catalytic performance in alkene epoxidation

BACKGROUND

Existing methods for alkene epoxidation are based on lipase-catalysed perhydrolysis. However, the inactivation of the expensive lipase enzyme is problematic for enzymatic epoxidation at large scales due to the use of hydrogen peroxide and peracids at high concentrations in the reaction. The immobilisation of whole cells appears to be a promising approach to alleviate this problem.

RESULTS

A green oxidation system containing hydrogen peroxide, Na₃C₆H₅O₇, an acyl donor, and glutaraldehyde (GA)-crosslinked cells of Rhizopus oryzae was developed for the epoxidation of alkenes. GA-crosslinked cells of Rhizopus oryzae were adopted as a biocatalyst into the epoxidation system. A variety of alkenes were oxidised with this system, with a 56-95% analytical yield of the corresponding epoxides. The catalytic performance of the crosslinked treated cells was substantially improved compared to that of the untreated cells and the initial reaction rate increased from 126.71 to 234.72 mmol/L/h, retaining 83% yields even after four batches of reactions. The addition of 3.5 mmol Na₃C₆H₅O₇ not only acts as an acid-trapping reagent to eliminate the negative effect of the carboxylic acid on the alkene oxide but also forms a saturated salt solution with the aqueous phase, affecting the concentration of H₂O₂ in the three phases and thus the epoxidation reaction. Organic solvents with a logP value > 0.68 were good at producing hydroxy peracids; however, this method is only suitable for oxidation in a two-liquid phase.

CONCLUSIONS

Compared with other lipase biocatalysts, the GA-crosslinked whole-cell biocatalyst is inexpensive, readily available, and highly stable. Therefore, it can be considered promising for industrial applications.

Polarization dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror

We investigate experimentally the polarization dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror in the cavity. We demonstrate that the normalized Stokes parameters and degree of polarization are functions of time reaching extreme values around the pulse peaks. Our experiments show that light is elliptically polarized, being able to have a circular right-handed or left-handed component, depending on the orientation of the saturable absorber mirror.

[Trust in vaccination and its influencing factors among parents of children aged 0-6 years]

Objective: To analyze the trust in vaccination and its influencing factors in parents of children aged 0-6 years. Methods: In June 2021, a cross-sectional survey was conducted to collect the basic information of parents of children aged 0-6 years, including their trust in vaccination and their attitudes towards vaccination. The χ² test was used to compare the difference between different groups, and logistic regression was used to analyze the influencing factors. Results: A total of 10 916 parents of children aged 0-6 years were investigated in this study, and their trust in vaccine was 67.20%, of which safety (55.80%) was the key factor limiting the trust in vaccination. 37.94% (4 142/10 916) of the parents were willing to vaccinate more than two kinds of vaccines at the same time, and 85.07% (9 286/10 916) of the parents feared that abnormal reactions would occur after vaccination. The parents' age, education level and annual family income were the promoting factors of their trust in vaccination (P<0.05). Obtaining vaccine knowledge through vaccination APP or official account (OR=1.330, 95%CI: 1.188-1.489) and popular science leaflets distributed by vaccination clinics (OR=1.120, 95%CI: 1.020-1.228) were the promoting factors of parents' trust in vaccination. Young children and parents, high family income and education level were the promoting factors for parents to be willing to vaccinate at the same time (P<0.05), and young children and parents, low family income and education level were the inducing factors for fear of abnormal reaction after vaccination (P<0.05). Parents of children in the central region had a high acceptance of simultaneous vaccination for children, while parents of children in the western region had a low degree of concern about abnormal reactions after vaccination (P<0.05). Parents of children who read books and got vaccine knowledge online (OR=1.257, 95%CI: 1.153-1.371), urban residents (OR=1.173, 95%CI: 1.062-1.295) and with jobs (OR=1.109, 95%CI: 1.015-1.212) were more willing to vaccinate at the same time. The choice of imported vaccine was a promoting factor for parents to worry about abnormal reactions after vaccination (P<0.05). Conclusion: There is room for parents of children aged 0-6 years to further improve their trust in vaccination. At this stage, it is necessary to innovate the way of health education and health promotion, and pay attention to the publicity of vaccine safety knowledge, so as to improve parents' trust in vaccination.

[Analysis for dropout of DTaP routine immunization in China in 2019]

Objective: To analyze the dropout of adsorbed diphtheria, tetanus and acellular pertussis combined vaccine (DTaP) routine immunization in China in 2019. Methods: DTaP vaccination data in all counties in China were collected through National Immunization Program Information Management System in 2019. Cumulative dropout rate and vaccination rate of DTaP in different provinces were calculated. According to the P₂₅, P₅₀ and P₇₅ values of DTaP dropout rate for all counties by province, counties in each province were divided into four groups (Q₁-Q₄). The DTaP average dropout rate of four groups and absolute difference (difference in DTaP average dropout rate between Q₄ and Q₁) were calculated. Spearman rank correlation was used to analyze the relationship between absolute difference and provincial DTaP dropout rate, DTaP₁ and DTaP₃ vaccination rate. Results: DTaP₁ vaccination rate ranged from 92.98% to 99.94% by province, with a median of 99.55%. Provincial DTaP dropout rate ranged from 0.36% to 28.66%, with a median of 3.54%. The provincial DTaP dropout rate was more than 10% in Gansu and Guizhou, about 28.66% and 17.19%. Absolute difference ranged from 4.02% to 39.22%, with a median of 10.16%. Provinces with the largest absolute difference were Gansu, Qinghai, Liaoning and Guizhou, about 39.22%, 34.48%, 23.31% and 21.33%, respectively. Correlation analysis indicated that the absolute difference was positively correlated with provincial DTaP dropout rate, with a correlation coefficient of 0.492 (P=0.004). It was negatively correlated with DTaP₁ and DTaP₃ vaccination rate. Correlation coefficients were -0.542 (P=0.001) and -0.562 (P=0.001), respectively. Conclusions: There are significant county-level differences in DTap dropout rate in most provinces, with relatively high difference in western provinces.

Modeling and Distribution Identification of Instantaneous Cutting Energy Efficiency of Milling Cutter under Vibration

The instantaneous cutting energy efficiency of a milling cutter is an important index to evaluate the cutting performance of the milling cutter. The existing models for cutting energy efficiency ignore the differences in the instantaneous cutting energy efficiency of each cutter tooth. In this work, according to the influence of milling vibration on instantaneous cutting posture and the input and output energy, a correlation model of the instantaneous cutting energy efficiency of a milling cutter and its cutter teeth was established. Using the cutting-force energy efficiency and the specific cutting energy and their distribution on the cutting edge of the cutter teeth, the dynamic relationship between the effective cutting energy transfer and conversion of the milling cutter was characterized. The instantaneous cutting-force energy efficiency and specific cutting energy were calculated. The formation of the dynamic distribution of the cutting energy efficiency was unveiled. Finally, an identification method for distributive variation in the instantaneous cutting energy efficiency of the milling cutter was proposed. The response of the distribution of the instantaneous cutting energy efficiency was studied and verified using experiments. The results showed that there was high similarity and good agreement between the calculated and measured results of the cutting energy efficiency of the milling cutter.

[Expert recommendations on human papillomavirus vaccine immunization strategies in China]

HPV vaccination is the most effective way for preventing the cervical cancer. To respond the WHO calling for cervical cancer elimination, some Chinese provincial governments are launching the Free HPV Vaccination Programs for teenagers. Basing on the current stage of domestic utilization and the global immunization strategies of HPV vaccination, this paper provides a comprehensive review of the key aspects in the process of HPV vaccination, including subjects and priority vaccination population, vaccination dose and time interval, the principal of vaccination replacement, and the vaccination suggestion on special populations, etc. The article above contents and gives the advice on the immunization strategy of HPV vaccination in China.

Layered protein nanoparticles containing influenza B HA stalk induced sustained cross-protection against viruses spanning both viral lineages

The influenza epidemics pose a significant threat to public health. Of them, type B influenza coincided with several severe flu outbreaks. The efficacy of the current seasonal flu vaccine is limited due to the antigenicity changes of circulating strains. In this study, we generated structure-stabilized HA stalk antigens from influenza B and fabricated double-layered protein nanoparticles as universal influenza B vaccine candidates. In vitro studies found that the resulting protein nanoparticles were effectively taken up to activate dendritic cells. Nanoparticle immunization induced broadly reactive immune responses conferring robust and sustained cross-immune protection against influenza B virus strains of both lineages. The results reveal the potential of layered protein nanoparticles incorporated with structure-stabilized constant antigens as a universal influenza vaccine with improved immune protective potency and breadth.

Graphene Oxide and Metal-Organic Framework-Based Breathable Barrier Membranes for Toxic Vapors

Garments protective against chemical warfare agents (CWAs) or accidently released toxic chemicals must block the transport of toxic gases/vapors for a substantial time and allow moisture transport for breathability. These demands are challenging: either the barriers block CWAs effectively but have poor breathability or barriers have excellent breathability but cannot block CWAs well. Existing protective garments employ large amounts of active carbon, making them quite heavy. Metal-organic framework (MOF)-based adsorbents are being investigated as sorbents for CWAs. Breathable laminate of graphene oxide (GO) flakes supported on a porous membrane reduces permeation rates of CWA simulants substantially. We developed a multilayered membrane-based flexible barrier: GO laminate-based membrane over a MOF nanocrystal-filled expanded polytetrafluorethylene (ePTFE) membrane having submicrometer pores. The GO laminate-based layer developed a steady breakthrough concentration level almost 2 orders of magnitude below the usual breakthrough level. This highly reduced level of CWA was blocked by the MOF nanocrystal-filled membrane substrate layer over a highly extended period. We demonstrated the blocking of CWAs, mustard (HD), soman (GD), a sarin simulant [dimethyl methyl phosphonate (DMMP)], and ammonia for an extended period while the moisture transmission rate was substantial. The times for complete blockage of ammonia, HD, GD, and DMMP were 2750 min, 1075 min, 176 min, and 7 days, respectively. This remarkable performance resulted from a very low steady-state penetrant permeation through GO-laminate membrane and substantial penetrant sorption by MOF nanocrystals; furthermore, both layers show high moisture vapor transmission.

[Efficacy and safety of carotid endarterectomy combined with endovascular therapy in hybrid operating room for patients with segmental atherosclerotic internal carotid artery occlusion]

The current study aimed to investigate the efficacy and safety of carotid endarterectomy combined with endovascular therapy in hybrid operating room for patients with segmental atherosclerotic internal carotid artery occlusion, and share the experience of preoperative screening of patients suitable for vascular reconstruction. A total of 20 patients with internal carotid artery occlusion (ICAO) who were admitted to the Department of Neurosurgery, General Hospital of Tianjin Medical University from May 2018 to May 2020 were collected, and 15 patients met the inclusion criteria. All patients received hybrid surgery. The total success rate of recanalization was 14/15, and only 1 patient developed ICA re-occlusion at 1 year follow up.Therefore, carotid endarterectomy combined with endovascular treatment in hybrid operating room was an alternative treatment for patients with segmental atherosclerotic internal carotid artery occlusion.

Identification and expression assay of calcium-dependent protein kinase family genes in Hevea brasiliensis and determination of HbCDPK5 functions in disease resistance

Calcium (Ca2+) signaling is one of the earliest factors to coordinate plant adaptive responses. As direct sensors and activators of Ca2+ signals, calcium-dependent protein kinases (CDPKs) were reported to be widely involved in regulating different biotic and abiotic stress stimuli. In this study, 32 Hevea brasiliensis CDPK (HbCDPK) genes were predicted and classified into four subgroups. Among them, the full-length coding sequences of 28 HbCDPK genes were confirmed by RT-PCR and verified by sequencing. Putative cis-elements assay in the promoters of HbCDPKs showed that most of the HbCDPK genes contained gibberellic acid-responsive element (GARE), abscisic acid-responsive element (ABRE), salicylic acid-responsive element (SARE), defense and stress responsive element (TC-rich repeats) and low-temperature response element (LTR), which could be activated by different biotic and abiotic stresses. Real-time PCR analysis indicated that 28 HbCDPK genes respond to infection of pathogenic fungi and a variety of phytohormones. Subcellular localization was observed with most HbCDPKs located in cell membrane, cytoplasm or organelles. Some HbCDPKs were confirmed to cause reactive oxygen species (ROS) production and accumulation in rubber tree mesophyll protoplast directly. HbCDPK5 was strongly induced by the inoculation with Colletotrichum gloeosporioides and was chosen for further analysis. HbCDPK5 localized to the cell membrane and cytoplasm, and obviously regulated the accumulation of ROS in rubber tree mesophyll protoplast. Overexpression of HbCDPK5 in Arabidopsis enhanced the resistance to Botrytis cinerea. These results indicate that rubber tree CDPK genes play important roles in plant disease resistance.

Real-time dynamics of noise-like vector pulses in a figure-eight fiber laser

The vector nature of noise-like pulses (NLPs) in a figure-eight erbium-doped fiber laser based on the nonlinear amplifier loop mirror (NALM) configuration is experimentally investigated. After achieving the operation regime of NLPs, both the group velocity locked noise-like vector pulses (GVL-NLVPs) and the polarization locked noise-like vector pulses (PL-NLVPs) are observed in the cavity. By virtue of the dispersive Fourier transform (DFT) technique, their spectral evolution and the energy vibration are measured and analyzed in real time. We also obtain another state of noise-like vector pulses (NLVPs) with combined characteristics of GVL-NLVPs and PL-NLVPs. It is shown that the NLVPs are sensitive to the cavity birefringence. Our results would be beneficial to complement the understanding of vector dynamics of NLPs in ultrafast fiber lasers.

Graphene-enhanced polarization-insensitive all-optical wavelength conversion based on four-wave mixing

All-optical wavelength conversion technology based on four-wave mixing (FWM) effect is a promising development need of the modern high-speed optical signal processing system. In this work, we report on the polarization insensitive four-wave mixing based on graphene for all optical wavelength conversion. To overcome the polarization sensitivity of FWM, a dual-pump configuration was proposed based on the combination of graphene and the optical fibers. Our experimental results illustrate that by using the dual pump configuration, the FWM-based wavelength conversion efficiency, can be enhanced by graphene with about 8 dB when the state of polarization of the two pumps are parallel. This proposed all-optical wavelength converter based on graphene may provide a new approach for the next generation optical communications and signal processing.

Influenza NP core and HA or M2e shell double-layered protein nanoparticles induce broad protection against divergent influenza A viruses

Influenza viral infection causes acute upper respiratory diseases in humans, posing severe risks to global public health. However, current vaccines provide limited protection against mismatched circulating influenza A viruses. Here, the immune responses induced in mice by novel double-layered protein nanoparticles were investigated. The nanoparticles were composed of influenza nucleoprotein (NP) cores and hemagglutinin (HA) or matrix 2 protein ectodomain (M2e) shells. Vaccination with the nanoparticles significantly enhanced M2e-specific serum antibody titers and concomitant ADCC responses. Robust NP-specific T cell responses and robust HA neutralization were also detected. Moreover, vaccination with a trivalent nanoparticle combination containing two routinely circulated HA, conserved M2e, and NP reduced lung virus titers, pulmonary pathologies, and weight loss after homologous virus challenge. This combination also improved survival rates against heterologous and heterosubtypic influenza virus challenges. Our results demonstrate that the trivalent combination elicited potent and long-lasting immune responses conferring influenza viral cross-protection.

Tailoring the ultrafast and nonlinear photonics of MXenes through elemental replacement

Due to the outstanding electronic properties, unique chemical surface termination units and rich elemental compositions, MXenes have become promising candidates for the development of new generation optoelectronic devices. However, there is still a gap between advanced photonics applications and fundamental understanding of ultrafast carrier photo-physics dynamics and a nonlinear optical response in layered MXenes. Here, we present insight into the excited state relaxation processes and nonlinear optical response of few-layer Ti₃CN and Ti₃C₂ nanosheets (NSs) via transient absorption spectroscopy and Z-scan measurements. Owing to similar structural compositions, the transient absorption and nonlinear absorption characteristics behave totally opposite. In addition, photo-induced bandgap renormalization and Pauli blocking phenomena exist in Ti₃C₂ and Ti₃CN NSs, respectively. The element replacement may be a new strategy for tunable carrier kinetics and nonlinear optical response of MXenes. These research studies may provide insight into ultrafast carrier photo-physics dynamics as well as promote MXene-based advanced photonics and their applications in optoelectronic devices.

Discrete light bullets in coupled optical resonators

We consider arrays of coupled nonlinear optical cavities subject to coherent optical injection. These devices are described by the discrete generalized Lugiato-Lefever equation. We predict that stable three-dimensional localized structures, often called discrete light bullets, and clusters of them may form in the output of the coupled optical resonators. We consider both anomalous and normal dispersion and show that it results in the generation of, respectively, bright and dark discrete light bullets.

Skin vaccination with dissolvable microneedle patches incorporating influenza neuraminidase and flagellin protein nanoparticles induces broad immune protection against multiple influenza viruses

We generated self-adjuvanted protein nanoparticles of conserved influenza antigens and immunized mice via skin vaccination with dissolvable microneedle patches (MNPs) to increase the strength and breadth of immune responses. We produced M2e nanoparticles via ethanol desolvation, and double-layered NA1/M2e (shell/core), NA1-FliC/M2e, NA2/M2e, and NA2-FliC/M2e protein nanoparticles by chemically crosslinking influenza NA and flagellin (FliC) onto the surfaces of the M2e nanoparticles. The resulting nanoparticles retained FliC TLR5 innate signaling activity and significantly increased antigen-uptake and dendritic cell maturation in vitro. We incorporated the nanoparticles into MNPs for skin vaccination in mice. The nanoparticle MNPs significantly increased M2e and NA-specific antibody levels, the numbers of germinal center B cells, and IL-4 positive splenocytes. Double-layered nanoparticle MNP skin vaccination protected mice against homologous and heterosubtypic influenza viruses. Our results demonstrated that MNP skin vaccination of NA-FliC/M2e nanoparticles could be developed into a standalone or synergistic component of a universal influenza vaccine strategy.

[Effect of VDR gene silencing on proliferation and NF-κB activation of airway smooth muscle cells]

Objective: To investigate the effect of VDR gene silencing on proliferation of airway smooth muscle cells (ASMCs) and elucidate the role of NF-κB. Methods: A recombinant lentiviral vector specifically targeting VDR gene in rat was constructed by RNA interference. Rat ASMCs were divided into blank group, empty vector group and interference group. ASM cell line model stably silencing the VDR gene RNA expressing was selected by puromycin. Then MTT colorimetric assay and cell cycle analysis by flow cytometry were used to examine cell proliferation. The activation of nuclear factor-κB was determined by immunofluorescence double label method. Moreover, NF-κB-dependent transcription activity was tested through luciferase reporter gene assay. Western blotting was used for IκBα and phospho-IκBα protein levels and actinomycin D treatment was used to determine IκBα mRNA stability. All statistical analyses were performed using SPSS version 23.0 software. Differences between groups were analyzed using one-way ANOVA analysis. Multiple comparisons among groups were made by Student-Newman-Keuls test. Results: (1) As compared with those in the blank group and the empty vector group, the cell proliferation index (PI) and the percent of ASMCs at G₂/M phase in the interference group were markedly increased (P<0.05), but their percent at G_0/1 phase was decreased (P<0.05).(2) In the interference group, the nuclear translocation of NF-κB p65 in ASMCs was obviously induced. And its level of receptor gene NF-κB p65 (1.37±0.28) was significantly higher than that in the blank group (1.00±0.19,P=0.031) and in the empty vector group (0.96±0.18,P=0.027).(3) In the interference group, the IκBα protein level in ASMCs (0.13±0.04) was obviously less than that in the blank group (0.29±0.05, P=0.023) and in the empty vector group (0.32±0.07, P=0.014). Oppositely, the p-IκBα/IκBα level in the interference group (0.86±0.04) was much more than that in the blank control group (0.41±0.07, P=0.026) and in the empty vector group (0.37±0.05, P=0.017). (4) In the interference group, IκBα mRNA showed a shorter half-life, (171.31±9.67) min, compared to that in the blank group [(224.69±7.95) min,P=0.032] and in the empty vector group [(230.41±6.37) min,P=0.035]. Conclusion: VDR gene silencing could promote ASMC proliferation and the underlying mechanism may involve the activation of NF-κB signaling pathway.

Intranasal vaccination with influenza HA/GO-PEI nanoparticles provides immune protection against homo- and heterologous strains

Intranasal (i.n.) immunization is a promising vaccination route for infectious respiratory diseases such as influenza. Recombinant protein vaccines can overcome the safety concerns and long production phase of virus-based influenza vaccines. However, soluble protein vaccines are poorly immunogenic if administered by an i.n. route. Here, we report that polyethyleneimine-functionalized graphene oxide nanoparticles (GP nanoparticles) showed high antigen-loading capacities and superior immunoenhancing properties. Via a facile electrostatic adsorption approach, influenza hemagglutinin (HA) was incorporated into GP nanoparticles and maintained structural integrity and antigenicity. The resulting GP nanoparticles enhanced antigen internalization and promoted inflammatory cytokine production and JAWS II dendritic cell maturation. Compared with soluble HA, GP nanoparticle formulations induced significantly enhanced and cross-reactive immune responses at both systemic sites and mucosal surfaces in mice after i.n. immunization. In the absence of any additional adjuvant, the GP nanoparticle significantly boosted antigen-specific humoral and cellular immune responses, comparable to the acknowledged potent mucosal immunomodulator CpG. The robust immune responses conferred immune protection against challenges by homologous and heterologous viruses. Additionally, the solid self-adjuvant effect of GP nanoparticles may mask the role of CpG when coincorporated. In the absence of currently approved mucosal adjuvants, GP nanoparticles can be developed into potent i.n. influenza vaccines, providing broad protection. With versatility and flexibility, the GP nanoplatform can be easily adapted for constructing mucosal vaccines for different respiratory pathogens.

Zn Induces Lipophagy via the Deacetylation of Beclin1 and Alleviates Cu-Induced Lipotoxicity at Their Environmentally Relevant Concentrations

In this study, the mechanisms of environmentally relevant doses of Cu and Zn mixtures influencing lipid deposition and metabolism were investigated in freshwater teleost yellow catfish Pelteobagrus fulvidraco (2 months old, 4.95 (t0.01 g, mean ± SEM). Our study indicated that waterborne Cu exposure increased lipid content, while Zn activated lipophagic flux and alleviated Cu-induced lipid accumulation. Yellow catfish hepatocytes treated with Zn or Zn + Cu activated autophagy-specific lipophagy, decreased lipid storage, and increased nonesterified fatty acid (NEFA) release, suggesting a causal relationship between lipophagy and lipid droplet (LD) breakdown under Zn and Zn + Cu conditions. Our further investigation found that Beclin1 deacetylation by sirtuin 1 (SIRT1) was required for Zn- and Zn + Cu-induced lipophagy and lipolysis, and lysine residues 427 and 434 were key sites for Beclin1 deacetylation. Taken together, these findings show that the Zn-induced deacetylation of Beclin1 promotes lipophagy as an important pathway to alleviate Cu-induced lipid accumulation in fish, which reveals a previously unidentified mechanism for understanding the antagonistic effects of Cu and Zn on metabolism at their environmentally relevant concentrations. Our results highlight the importance of combined exposure when the biological effects of heavy metals are evaluated during environmental risk assessments.

Broadband Nonlinear Photonics in Few-Layer Borophene

In this paper, 2D borophene is synthesized through a liquid-phase exfoliation. The morphology and structure of as-prepared borophene are systemically analyzed, and the Z-scan is used to measure the nonlinear optical properties. It is found that the saturable absorber (SA) properties of borophene make it serve as an excellent broadband optical switch, which is strongly used for mode-locking in near- and mid-infrared laser systems. Ultrastable pulses with durations as short as 792 and 693 fs are successfully delivered at the central wavelengths of 1063 and 1560 nm, respectively. Furthermore, stable pulses at a wavelength of 1878 nm are demonstrated from a thulium mode-locked fiber laser based on the same borophene SA. This research reveals a significant potential for borophene used in lasers helping extending the frontiers of photonic technologies.

Simultaneous generation and real-time observation of loosely bound solitons and noise-like pulses in a dispersion-managed fiber laser with net-normal dispersion

We demonstrate the coexisting dynamics of loosely bound solitons and noise-like pulses (NLPs) in a passively mode-locked fiber laser with net-normal dispersion. The total pulse number of the single soliton bunch under the NLP operation regime almost increases linearly with increasing pump power, whereas the average pulse spacing decreases accordingly. Furthermore, pulse-to-pulse separation between adjacent soliton pulses in one soliton bunch keeps in the range of hundreds of picoseconds, which decreases from left to right with the change of time. Besides, the real-time observation has been performed by utilizing the time-stretch method, showing that each one of the loosely bound solitons on the NLP operation is actually composed of chaotic wave packets with random intensities. These findings obtained will facilitate the in-depth understanding of nonlinear pulse behaviors in ultrafast optics.

Band structure tuning of α-MoO3 by tin intercalation for ultrafast photonic applications

van der Waals (vdW) transition metal oxides have attracted extensive attention due to their intriguing physical and chemical properties. However, primary drawbacks of these materials are the lack of band structure tunability and substandard optical properties, which severely hinder their implementation in nanophotonic applications. Atomic intercalation is an emerging structural engineering approach for two-dimensional vdW materials to engineer the atomic structure and modify the optical properties, thereby broadening their range of applications. Herein, we synthesized tin-intercalated ultrathin α-MoO3 (Sn-MoO3) nanoribbons via chemical intercalation method and then investigated the broadband nonlinear optics (NLO) of stable few-layer α-MoO3 by performing a Z-scan laser measurement and femtosecond-resolved transient absorption (TA) spectroscopy. Sn-MoO3 showed a stable structure of Mo-O-Sn-O-Mo and a shorter relaxation time than pristine MoO3, indicating the accelerated recombination process of electrons and holes. Furthermore, Sn-MoO3 nanoribbons were used as an optical saturable absorber for ultrafast photonics; a highly stable femtosecond laser with a pulse width of 467 fs was generated from a single-mode fiber in the telecommunication band (1550 nm). These results indicate that atomic intercalation is an effective way to modulate the band structure and nonlinear optical properties of α-MoO3, which hold a great potential in the generation of ultrafast mode-locked laser pulses for optical communication technologies.

Recent advances in real-time spectrum measurement of soliton dynamics by dispersive Fourier transformation

Mode-locking lasers have not only produced huge economic benefits in industrial fields and scientific research, but also provided an excellent platform to study diverse soliton phenomena. However, the real-time characterization of the ultrafast soliton dynamics remains challenging for traditional electronic instruments due to their relatively low response bandwidth and slow scan rate. Consequently, it is urgent for researchers to directly observe these ultrafast evolution processes, rather than just indirectly understand them from numerical simulations or averaged measurement data. Fortunately, dispersive Fourier transformation (DFT) provides a powerful real-time measurement technique to overcome the speed limitations of traditional electronic measurement devices by mapping the frequency spectrum onto the temporal waveform. In this review, the operation principle of DFT is discussed and the recent progress in characterizing the ultrafast transient soliton dynamics of mode-locking lasers is summarized, including soliton explosions, soliton molecules, noise-like pulses, rogue waves, and mode-locking buildup processes.

Recent Advances of Spatial Self-Phase Modulation in 2D Materials and Passive Photonic Device Applications

Optical nonlinearity in 2D materials excited by spatial Gaussian laser beam is a novel and peculiar optical phenomenon, which exhibits many novel and interesting applications in optical nonlinear devices. Passive photonic devices, such as optical switches, optical logical gates, photonic diodes, and optical modulators, are the key compositions in the future all-optical signal-processing technologies. Passive photonic devices using 2D materials to achieve the device functionality have attracted widespread concern in the past decade. In this Review, an overview of the spatial self-phase modulation (SSPM) in 2D materials is summarized, including the operating mechanism, optical parameter measurement, and tuning for 2D materials, and applications in photonic devices. Moreover, some current challenges are also proposed to solve, and some possible applications of SSPM method are predicted for the future. Therefore, it is anticipated that this summary can contribute to the application of 2D material-based spatial effect in all-optical signal-processing technologies.

A nano-lateral heterojunction of selenium-coated tellurium for infrared-band soliton fiber lasers

In this work, ultrafast fiber lasers based on 2D selenium-coated tellurium nanosheets in the infrared band are reported. 2D selenium-coated tellurium as a mode locker is shown with broadband saturable absorption and is capable of supporting ultra-stable pulse trains with several hundred-femtosecond pulse widths in the laser cavity. In particular, the as-fabricated 2D selenium-coated tellurium based fiber laser source operating in the communication band (1.5 μm) exhibits the vector pulse property, which supports the study of the vector soliton in ultrafast fiber lasers. The pulse duration of vector solitons is as short as 800 fs. The 2D selenium-coated tellurium is also available for a mode locked fiber laser operating at 1 μm. The laser oscillator has a pulse duration of several picoseconds and the pulse train is ultra-stable after an amplification to 100 mW, which is a promising seed source in the chirped-pulse amplification system in the future.

Control of dissipative rogue waves in nonlinear cavity optics: Optical injection and time-delayed feedback

We investigate and review the formation of two-dimensional dissipative rogue waves in cavity nonlinear optics with transverse effects. Two spatially extended systems are considered for this purpose: the driven Kerr optical cavities subjected to optical injection and the broad-area surface-emitting lasers with a saturable absorber. We also consider a quasi-two-dimensional system (the two dimensions being space and time) of a fiber laser describing the complex cubic-quintic Ginzburg-Landau equation. We show that rogue waves are controllable by means of time-delayed feedback and optical injection. We show that without delayed feedback, transverse structures are stationary or oscillating. However, when the strength of the delayed feedback is increased, all the systems generate giant two-dimensional pulses that appear with low probability and suddenly appear and disappear. We characterize their formation by computing the probability distribution, which shows a long tail. Besides, we have computed the significant wave height, which measures the mean wave height of the highest third of the waves. We show that for all systems, the distribution tails expand beyond two times the significant wave height. Furthermore, we also show that optical injection may suppress the rogue wave formation in a semiconductor laser with a saturable absorber.

Preparation of a Phenolic-Resin-Based Polymer Sponge Composed of Intertwined Nanofibers with Tunable Wettability for High-Efficiency Separation of Oil-Water Emulsions

Nowadays, as the combination of water pollution and water shortage causes severe environmental and social issues, the special wettable materials, which can be selectively wetted by either water or oil, attract tremendous attention for high-efficiency separation of oil-water mixtures. Herein, we prepare a phenolic-resin-based sponge composed of intertwined nanofibers via a simple hydrothermal method. The wettability of the as-prepared polymer is tuned readily by controlling only the hydrothermal temperature. In the case of the hydrothermal temperature below 210 °C, the polymer sponge demonstrates superhydrophilic and underwater superoleophobic properties, affording the separation of oil-in-water emulsions. However, as the hydrothermal temperature increases above 220 °C, the resulting bulk phenolic-resin-based material becomes superhydrophobic and underoil superhydrophobic, realizing a high filtration flux of 6147 L m^-2 h^-1 for the separation of water-in-oil emulsions driven by an external pressure of 40 kPa. This provides a feasible platform for future practical applications. The wettability transition depending on the hydrothermal temperature is discussed in terms of the reaction mechanism. In addition, the stability and breakthrough pressure are also addressed from the viewpoints of thermodynamic and fluid mechanics, respectively.

Black phosphorus quantum dot based all-optical signal processing: ultrafast optical switching and wavelength converting

As a unique two-dimensional material, few-layered black phosphorus (BP) nanosheets have shown promising applications in electronics and optoelectronics. Black phosphorus quantum dots (BPQDs) have attracted attention due to the unique properties of BP combined with the edge effects. In this paper, we report on the all-optical application of BPQD based on its nonlinear Kerr effect. BPQDs were synthesized using a liquid exfoliation method combined with probe sonication and bath sonication. BPQD deposited on the microfiber as an optical device was demonstrated as the Kerr switcher with extinction ratio of 20 dB and four-wave mixing based wavelength converter with -40 dB conversion efficiency. These findings suggest that BPQD-based novel nonlinear photonics devices could be further developed in the applications of next generation high-speed optical communication.