Binocular Visual Deficits at Low to High Spatial Frequency in Intermittent Exotropia After Surgery.

Purpose: To investigate binocular visual deficits at low to high spatial frequencies in patients with intermittent exotropia (IXT) after surgical correction, using the binocular orientation combination task. Methods: Thirteen patients whose IXT has been aligned surgically (17 ± 4.8 years old; 7 females) and 13 normal individuals (21.8 ± 2.5 years old; 6 females) were recruited. All participants had normal or corrected-to-normal visual acuity. The IXT patients had undergone surgery at least one month prior to the study and achieved successful eye alignment post-surgery. We measured participants' balance points (BPs), defined as the interocular contrast ratio (nondominant eye/dominant eye) when both eyes contributed equally to binocular combination, using the binocular orientation combination task at three spatial frequencies (0.5, 4.0, and 8.0 cycles/degree). The absolute values of log10(BP) (i.e., |logBP|) and the area under of the |logBP| versus spatial frequency curve were used to quantify the extent of binocular imbalance. Results: Surgery aligned the eye position of patients with IXT, with a postoperative exodeviation of -4.92 ± 4.29 prism diopters at distance. Participants' |logBP| values showed significant differences between groups, F(1,24) = 9.175, P = 0.006, and across spatial frequencies, F(2,48) = 7.127, P = 0.002. However, the interaction between group and spatial frequency was not significant, F(2,48) = 0.379, P = 0.687. Conclusions: Patients whose IXT has been alighted surgically experience binocular imbalance across a wide range of spatial frequencies, with greater binocular imbalance occurring at high spatial frequencies than low spatial frequencies.

Trans-Cinnamaldehyde Inhibition of Pyruvate Dehydrogenase: Effects on Streptococcus mutans Carbohydrate Metabolism.

Dental caries is a chronic oral infectious disease, and Streptococcus mutans (S. mutans) plays an important role in the formation of dental caries. Trans-cinnamaldehyde (CA) exhibits broad-spectrum antibacterial activity; however, its target and mechanism of action of CA on S. mutans needs to be further explored. In this study, it was verified that CA could inhibit the growth and biofilm formation of S. mutans. Further proteomic analysis identified 33, 55, and 78 differentially expressed proteins (DEPs) in S. mutans treated with CA for 1, 2, and 4 h, respectively. Bioinformatics analysis showed that CA interfered with carbohydrate metabolism, glycolysis, pyruvate metabolism, and the TCA cycle, as well as amino acid metabolism of S. mutans. Protein interactions suggested that pyruvate dehydrogenase (PDH) plays an important role in the antibacterial effect of CA. Moreover, the upstream and downstream pathways related to PDH were verified by various assays, and the results proved that CA not only suppressed the glucose and sucrose consumption and inhibited glucosyltransferase (GTF) and lactate dehydrogenase (LDH) activities but also decreased the ATP production. Interestingly, the protein interaction, qRT-PCR, and molecular docking analysis showed that PDH might be the target of CA to fight S. mutans. In summary, the study shows that CA interferes with the carbohydrate metabolism of bacteria by inhibiting glycolysis and the tricarboxylic acid (TCA) cycle via binding to PDH, which verifies that PDH is a potential target for the development of new drugs against S. mutans.

Deep learning for risk stratification of thymoma pathological subtypes based on preoperative CT images.

OBJECTIVES: This study aims to develop an innovative, deep model for thymoma risk stratification using preoperative CT images. Current algorithms predominantly focus on radiomic features or 2D deep features and require manual tumor segmentation by radiologists, limiting their practical applicability. METHODS: The deep model was trained and tested on a dataset comprising CT images from 147 patients (82 female; mean age, 54 years ± 10) who underwent surgical resection and received subsequent pathological confirmation. The eligible participants were divided into a training cohort (117 patients) and a testing cohort (30 patients) based on the CT scan time. The model consists of two stages: 3D tumor segmentation and risk stratification. The radiomic model and deep model (2D) were constructed for comparative analysis. Model performance was evaluated through dice coefficient, area under the curve (AUC), and accuracy. RESULTS: In both the training and testing cohorts, the deep model demonstrated better performance in differentiating thymoma risk, boasting AUCs of 0.998 and 0.893 respectively. This was compared to the radiomic model (AUCs of 0.773 and 0.769) and deep model (2D) (AUCs of 0.981 and 0.760). Notably, the deep model was capable of simultaneously identifying lesions, segmenting the region of interest (ROI), and differentiating the risk of thymoma on arterial phase CT images. Its diagnostic prowess outperformed that of the baseline model. CONCLUSIONS: The deep model has the potential to serve as an innovative decision-making tool, assisting on clinical prognosis evaluation and the discernment of suitable treatments for different thymoma pathological subtypes. KEY POINTS: • This study incorporated both tumor segmentation and risk stratification. • The deep model, using clinical and 3D deep features, effectively predicted thymoma risk. • The deep model improved AUCs by 16.1pt and 17.5pt compared to radiomic model and deep model (2D) respectively.

Clinical factors associated with remission of obese acanthosis nigricans after laparoscopic sleeve gastrectomy: a prospective cohort study.

BACKGROUND: Acanthosis nigricans (AN) involves skin hyperpigmentation in body folds and creases. Obesity-associated AN (OB_AN) is the most common type of AN. The skin condition of obese patients with AN can be improved through bariatric surgery, such as laparoscopic sleeve gastrectomy (LSG), after weight loss. However, the contributing factors to the remission of AN after surgery are still not fully determined. The authors aimed to assess the metabolic and pathological factors associated with remission of AN following LSG in obese individuals. METHODS: The study included 319 obese patients who underwent LSG at our hospital. The subjects were divided into obesity (OB) only (OB, n =178) or OB with AN (OB_AN, n =141) groups. The basic clinical and metabolic indices and the dermatological features via reflectance confocal microscopy and histology were collected from patients prior to and after LSG. RESULTS: OB_AN patients had higher fasting plasma glucose, homeostatic model assessment for insulin resistance, and testosterone levels than OB patients. LSG could significantly improve the biochemical and histopathological features of OB_AN patients. The remissive rate of OB_AN patients was about 86.5% (122 out of 141) after surgery. The remission of OB_AN skin lesions was positively correlated with testosterone levels ( P <0.01). In addition, there was a significant positive correlation between changes in AN scores and epidermal thickness and skin pigmentation scores after surgery ( P <0.01). CONCLUSION: The remissive rate of OB_AN after LSG is associated with improved testosterone levels and reduced epidermal thickness and skin pigmentation levels.

Application of Artificial Intelligence in Oncology Nursing: A Scoping Review.

BACKGROUND: Artificial intelligence (AI) has been increasingly used in healthcare during the last decade, and recent applications in oncology nursing have shown great potential in improving care for patients with cancer. It is timely to comprehensively synthesize knowledge about the progress of AI technologies in oncology nursing. OBJECTIVE: The aims of this study were to synthesize and evaluate the existing evidence of AI technologies applied in oncology nursing. METHODS: A scoping review was conducted based on the methodological framework proposed by Arksey and O'Malley and later improved by the Joanna Briggs Institute. Six English databases and 3 Chinese databases were searched dating from January 2010 to November 2022. RESULTS: A total of 28 articles were included in this review-26 in English and 2 in Chinese. Half of the studies used a descriptive design (level VI). The most widely used AI technologies were hybrid AI methods (28.6%) and machine learning (25.0%), which were primarily used for risk identification/prediction (28.6%). Almost half of the studies (46.4%) explored developmental stages of AI technologies. Ethical concerns were rarely addressed. CONCLUSIONS: The applicability and prospect of AI in oncology nursing are promising, although there is a lack of evidence on the efficacy of these technologies in practice. More randomized controlled trials in real-life oncology nursing settings are still needed. IMPLICATIONS FOR PRACTICE: This scoping review presents comprehensive findings for consideration of translation into practice and may provide guidance for future AI education, research, and clinical implementation in oncology nursing.

Development and Validation of Multi-Omics Thymoma Risk Classification Model Based on Transfer Learning.

The paper aims to develop prediction model that integrates clinical, radiomics, and deep features using transfer learning to stratifying between high and low risk of thymoma. Our study enrolled 150 patients with thymoma (76 low-risk and 74 high-risk) who underwent surgical resection and pathologically confirmed in Shengjing Hospital of China Medical University from January 2018 to December 2020. The training cohort consisted of 120 patients (80%) and the test cohort consisted of 30 patients (20%). The 2590 radiomics and 192 deep features from non-enhanced, arterial, and venous phase CT images were extracted and ANOVA, Pearson correlation coefficient, PCA, and LASSO were used to select the most significant features. A fusion model that integrated clinical, radiomics, and deep features was developed with SVM classifiers to predict the risk level of thymoma, and accuracy, sensitivity, specificity, ROC curves, and AUC were applied to evaluate the classification model. In both the training and test cohorts, the fusion model demonstrated better performance in stratifying high and low risk of thymoma. It had AUCs of 0.99 and 0.95, and an accuracy of 0.93 and 0.83, respectively. This was compared to the clinical model (AUCs of 0.70 and 0.51, accuracy of 0.68 and 0.47), the radiomics model (AUCs of 0.97 and 0.82, accuracy of 0.93 and 0.80), and the deep model (AUCs of 0.94 and 0.85, accuracy of 0.88 and 0.80). The fusion model integrating clinical, radiomics and deep features based on transfer learning was efficient for noninvasively stratifying high risk and low risk of thymoma. The models could help to determine surgery strategy for thymoma cancer.

Protective roles of tRNA-derived small RNA tRF-Ile-AAT-019 in pathological progression of psoriasis.

Psoriasis is a chronic recurrent inflammatory skin disease that is characterized by abnormal proliferation and differentiation of keratinocytes (KCs), angiogenesis and skin inflammation. Transfer RNA fragments (tRFs) are tRNA-derived small RNAs (tsRNAs), which possess regulatory functions in many diseases. Their potential roles in the pathological development of psoriasis have not been established. We first identified differentially expressed (DE) tRFs from psoriatic skin lesions using small RNA sequencing, and collected additional clinical samples for validation. Then, we investigated the function and mechanism of target tRFs in vitro. As a result of our investigation: we identified 234 DE transcripts in psoriatic skin lesions compared with normal controls. Further functional analysis showed the downregulation of tRF-Ile-AAT-019 in psoriatic lesions plays a critical role in pathogenesis since it could target 3'UTR of the serine protease serpin protein E1 (SERPINE1) gene. We next demonstrated that tRF-Ile-AAT-019 could suppress SERPINE1, thus leading to decreased expressions of vascular endothelial growth factor but increased expressions of keratinocytes (KCs) differentiation markers including Keratin1 and Involucrin. In conclusion, tRF-Ile-AAT-019 plays a protective role in the pathological progression of psoriasis via targeting SERPINE1, resulting in regulation of KCs differentiation and vascular proliferation biomarkers and providing a potential novel targeting pathway for the disease treatment.

Bioinformatic profiling identifies the glutaminase to be a potential novel cuproptosis-related biomarker for glioma.

Glioma is the most common tumour of the central nervous system, with a poor prognosis and an increasing trend of incidence in recent years; it is also beginning to affect younger age groups more. Added to this, cuproptosis is a new form of cell death. Indeed, when a certain amount of copper accumulates in a cell, it affects specific mitochondrial metabolic enzymes in that cell and leads to cell death-a phenomenon known as cuproptosis. In this study, we applied bioinformatics analysis, and, according to the results of the study analysis and Gene Ontology (GO), as well as the Kyoto Encyclopedia of Genes and Genomes KyotoEncyclopediaofGenesandGenomes, the glutaminase (GLS) genes affect the prognosis and tumour mutation of glioma patients through cuproptosis. Interestingly, however, GLS is not involved in the immune escape of glioma. Glutaminase genes are a class of glucose metabolism-related genes that are involved in the tricarboxylic acid cycle of cells. At the same time, the expression of the glutaminase gene was positively correlated with the degree of immune cell infiltration and the expression of various immune cell markers, and thus affected the prognosis of glioma patients. Therefore, we believe that the cuproptosis-related glutaminase gene can be an important factor in determining the prognosis of glioma patients.

The Prognostic Value of Tumor Size, Volume and Tumor Volume Reduction Rate During Concurrent Chemoradiotherapy in Patients With Cervical Cancer.

Objective: This study aimed to investigate the relationship between prognostic and tumor parameters of cervical cancer patients, such as tumor size (TS), tumor volume (TV), and tumor volume reduction rate (TVRR) after external beam radiotherapy. Methods: A total of 217 patients with advanced cervical cancer, classified as Federation of Gynecology and Obstetrics (FIGO) IIa-IVa, were enrolled in the study. Pre- and mid-RT pelvic magnetic resonance imaging (MRI) were performed twice, during RT and just before brachytherapy. Results: The median follow-up time was 51 months (range, 7-111 months). The 5-year overall survival (OS), progression-free survival (PFS), and local failure-free survival (LFFS) rates were 81.3, 85.1, and 92.9%, respectively. Multivariate analysis revealed that tumor parameters including FIGO stage >II (Hazard Ratio, 2.377 and 95% confidence interval [CI], 1.091-5.182; P = 0.029), pre-RT TV >61.6 cm3 (HR, 0.417 and 95% CI, 0.188-0.926; P = 0.032), and mid-RT TV >11.38 cm3 (HR, 3.192 and 95% CI, 1.094-9.316; P = 0.034) were observably associated with OS. Univariate analysis showed that the tumor volume reduction rate (TVRR) was dramatically associated with overall survival (HR, 0.204 and 95% CI 0.033-1.282; P <0.001) and local failure-free survival (P = 0.050). Conclusions: In this retrospective study, TVRR and mid-radiotherapy tumor volume are independent and strong prognostic parameters for patients with local advanced cervical cancer receiving CCRT.

Determining the critical buckling load of locally stiffened U-shaped steel sheet pile using dynamic correlation coefficient method.

U-Shaped Steel Sheet Piles (USSSP) have buckling and bending problems during construction. In this research, the structural measure of stiffened plates applied along the longitudinal direction of USSSP is analyzed and proposed. A theoretical calculation method of stiffening effect is proposed based on the dynamic correlation coefficient method and the formula for the critical buckling load of locally stiffened USSSP is derived. A parametric analysis of the number, width, and arrangement scheme of the stiffened plates on the USSSP with different lengths is examined. The empirical formula derived for the total stiffening area and the critical load of the axial compression members of the USSSP is compared with practical results from an engineering case study. The results show a quadratic function under the condition of arranging the different number of stiffened plates at equal intervals, which is accurate in deriving the critical load values USSSP after local stiffening, and provide a theoretical basis for the optimization design of local reinforcement of USSSP axial compression members in engineering projects.

Recent Progress of Novel Nanotechnology Challenging the Multidrug Resistance of Cancer.

Multidrug resistance (MDR) of tumors is one of the clinical direct reasons for chemotherapy failure. MDR directly leads to tumor recurrence and metastasis, with extremely grievous mortality. Engineering a novel nano-delivery system for the treatment of MDR tumors has become an important part of nanotechnology. Herein, this review will take those different mechanisms of MDR as the classification standards and systematically summarize the advances in nanotechnology targeting different mechanisms of MDR in recent years. However, it still needs to be seriously considered that there are still some thorny problems in the application of the nano-delivery system against MDR tumors, including the excessive utilization of carrier materials, low drug-loading capacity, relatively narrow targeting mechanism, and so on. It is hoped that through the continuous development of nanotechnology, nano-delivery systems with more universal uses and a simpler preparation process can be obtained, for achieving the goal of defeating cancer MDR and accelerating clinical transformation.

Single nucleotide polymorphisms within NFKBIA are associated with nasopharyngeal carcinoma susceptibility in Chinese Han population.

Genes involved in latent membrane protein 1 (LMP1) signaling pathways have been suggested to play an important role in nasopharyngeal carcinogenesis. We investigated potentially functional genetic variants associated with the risk of nasopharyngeal carcinoma (NPC) in genes involved in the LMP1 signaling pathway. Altogether, 73 single nucleotide polymorphisms (SNPs) with MAF ≥ 10% were located within the regions of interest of the four genes TRAF3, NFKBIA, CHUK and MAP2K4. From these, 10 SNPs were selected for genotyping based on LD (r2 ≥ 0.80) in a hospital-based case-control study of 332 NPC cases and 585 healthy controls from the Chinese Han population. Minor allele carriers of the promoter SNP rs2233409 in NFKBIA, had an increased risk of NPC (AA vs GG: OR 7.14, 95%CI, 1.08-34.18, P = 0.04, dominant model). Based on the results, we concluded that rs2233409 polymorphism in NFKBIA may be moderately associated with the risk of NPC. Further studies with larger independent samples and functional analysis are needed to verify our results.

MiR-4295 facilitates cell proliferation and metastasis in head and neck squamous cell carcinoma by targeting NPTX1.

It has been reported that MicroRNAs (miRNAs) play pivotal roles in the occurrence and progression of a variety of cancers. As reported, miR-4295 promotes cell growth and metastasis in a lot of cancers. Nonetheless, the role and molecular mechanism of miR-4295 in HNSCC still remain unknown. In this study, we discovered miR-4295 expression was significantly upregulated in HNSCC tissues and cell lines, which is also associated with the overall survival of patients. Additionally, suppression of miR-4295 significantly inhibited cell proliferation, migration and EMT process in HNSCC. Through Targetscan website, it was predicted that NPTX1 might be a direct target gene of miR-4295. Then, we verified that NPTX1 could directly interact with miR-4295 via luciferase reporter and RNA assays. What's more, we discovered that there was a significantly negative correlation between NPTX1 and miR-4295 expression. It was indicated by further investigation that the effect of miR-4295 suppression on cell proliferation, migration and EMT process in HNSCC can be restored by knockdown of NPTX1 at the same time. Our results suggested that miR-4295 promoted the progression of HNSCC via regulating NPTX1 expression and miR-4295/NPTX1 axis, which may be a new therapeutic strategy for HNSCC.

Association between iron deficiency and prevalence of thyroid autoimmunity in pregnant and non-pregnant women of childbearing age: a cross-sectional study.

BACKGROUND: Thyroid autoimmunity (TAI) is prevalent among women of reproductive age and associated with adverse pregnancy outcomes. This study aimed to investigate the association between iron nutritional status and the prevalence of TAI in women during the first trimester of pregnancy and in non-pregnant women of childbearing age. METHODS: Cross-sectional analysis of 7463 pregnant women during the first trimester of pregnancy and 2185 non-pregnant women of childbearing age nested within the sub-clinical hypothyroid in early pregnancy study, a prospective collection of pregnant and non-pregnant women's data, was conducted in Liaoning province of China between 2012 and 2015. Serum thyrotropin, free thyroxine, thyroid peroxidase antibodies (TPOAbs), thyroglobulin antibodies (TgAbs), serum ferritin, and urinary iodine were measured. Iron deficiency (ID) was defined as serum ferritin <15 µg/L and iron overload (IO) was defined as ferritin >150 µg/L. TPOAb-positive was defined as >34 U/mL and TgAb-positive was defined as >115 U/mL. Multilevel logistic regression was conducted to examine the association between TAI and different iron nutritional status after adjusting for potential confounders. RESULTS: The prevalence of isolated TPOAb-positive was markedly higher in women with ID than those without ID, in both pregnant and non-pregnant women (6.28% vs. 3.23%, χ = 10.264, P = 0.002; 6.25% vs. 3.70%, χ = 3,791, P = 0.044; respectively). After adjusting for confounders and the cluster effect of hospitals, ID remained associated with TPOAb-positive in pregnant and non-pregnant women (odds ratio [OR]: 2.111, 95% confidence interval [CI]: 1.241-3.591, P = 0.006; and OR: 1.822, 95% CI: 1.011-3.282, P = 0.046, respectively). CONCLUSION: ID was associated with a higher prevalence of isolated TPOAbs-positive, but not with isolated TgAb-positive, in both pregnant women during the first trimester of pregnancy and non-pregnant women of childbearing age, while IO was not associated with either isolated TPOAb-positive or isolated TgAb-positive. CLINICAL TRIAL REGISTRATION: ChiCTR-TRC-13003805, http://www.chictr.org.cn/index.aspx.

Glycyrrhizin, a Direct HMGB1 Antagonist, Ameliorates Inflammatory Infiltration in a Model of Autoimmune Thyroiditis via Inhibition of TLR2-HMGB1 Signaling.

BACKGROUND: High mobility group box-1 (HMGB1), a non-histone protein, plays an important role in autoimmune diseases. However, the significance of HMGB1 in the pathogenesis of autoimmune thyroiditis has not been reported. The purpose of this study was to explore whether HMGB1 participates in the pathogenesis of autoimmune thyroiditis, and whether glycyrrhizin (GL), a direct inhibitor of HMGB1, attenuates the severity of thyroid inflammatory infiltration in a murine model of autoimmune thyroiditis. METHODS: A total of 80 male NOD.H-2h4 mice were randomly divided into a control or iodine supplement (NaI) group at four weeks of age, and the control group was fed with regular water, whereas the NaI group was supplied with 0.005% sodium iodine water. Another 24 male NOD.H-2h4 mice were also randomized into three groups (eight mice per group) as follows: control, NaI, and GL treatment after iodine supplementation (NaI + GL). The NOD.H-2h4 mice were fed with 0.005% sodium iodide water for eight weeks to enhance autoimmune thyroiditis. After iodine treatment, the mice received intraperitoneal injections of GL for four weeks. The severity of lymphocytic infiltration in the thyroid gland was measured by histopathological studies. The serum levels of HMGB1, tumor necrosis factor alpha, interleukin (IL)-6, IL-1ß, and thyroglobulin antibody titers were measured using an enzyme-linked immunosorbent assay. HMGB1 expression was measured by immunohistochemical staining and real-time polymerase chain reaction. TLR2, HMGB1, MyD88, and nuclear transcription factor κB were measured by Western blot. RESULTS: The mRNA expression of HMGB1 was significantly higher at 8 and 16 weeks in the NaI group than it was in the control group. Serum levels of thyroglobulin antibodies, HMGB1, tumor necrosis factor alpha, IL-6, and IL-1ß were significantly increased in the NaI group, but they were dramatically attenuated with GL injection. The prevalence of thyroiditis and the infiltration of lymphocytes were significantly decreased in the NaI + GL group. GL administration also significantly reduced the protein expression of TLR2, MyD88, HMGB1 and nuclear transcription factor κB in the thyroid gland and attenuated the severity of thyroiditis. CONCLUSION: HMGB1 may play a crucial role in autoimmune thyroiditis by causing inflammatory infiltration, thus increasing the severity of autoimmune thyroiditis. GL effectively attenuated thyroiditis in the iodine-induced NOD.H-2h4 mice via a molecular mechanism related to the inhibition of TLR2-HMGB1 signaling.

Increased Toll-Like Receptors Activity and TLR Ligands in Patients with Autoimmune Thyroid Diseases.

OBJECTIVE: Autoimmune thyroid disease (AITD) is an organ-specific disorder due to the interplay between environmental and genetic factors. Toll-like receptors (TLRs) are pattern recognition receptors expressed abundantly on monocytes. There is a paucity of data on TLR expression in AITD. The aim of this study was to examine TLR expression, activation, ligands, and downstream signaling adaptors in peripheral blood mononuclear cells (PBMCs) extracted from untreated AITD patients and healthy controls. METHOD: We isolated PBMC of 30 healthy controls, 36 patients with untreated Hashimoto's thyroiditis, and 30 patients with newly onset Graves' disease. TLR mRNA, protein expression, TLR ligands, and TLR adaptor molecules were measured using real-time PCR, Western blot, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). PBMC was simulated with TLR agonists. The effects of TLR agonists on the viability of human PBMC were evaluated using the MTT assay. The supernatants of cell cultures were measured for the pro-inflammatory cytokines, interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), and IL-10 by ELISA. RESULTS: TLR2, TLR3, TLR9, and TLR10 mRNA were significantly increased in AITD patients compared with controls. TLR2, TLR3, TLR9, high mobility group box 1 (HMGB1), and RAGE expression on monocytes was higher in patients than control at baseline and TLR agonists' stimulation. The release of TNF-α and IL-6 was significantly increased in PBMCs from AITD patients with TLR agonists, while IL-10 was significantly decreased. Downstream targets of TLR, myeloid differentiation factor 88 (MyD88), and myeloid toll/IL-1 receptor-domain containing adaptor-inducing interferon-ß were significantly elevated in AITD patients. Levels of TLR2 ligands, HMGB1, and heat shock protein 60 were significantly elevated in AITD patients compared with those in controls and positively correlated with TgAb and TPOAb, while sRAGE concentration was significantly decreased in AITD patients. CONCLUSION: This work is the first to show that TLR2, TLR3, and TLR9 expression and activation are elevated in the PBMCs of patients with AITD and TLRs may participate in the pathogenesis of AITD.

Generating the orbital angular momentum of radio frequency signals using optical-true-time-delay unit based on optical spectrum processor.

A system for generating radio frequency signals with orbital angular momentum (OAM) is proposed and certificated for the first time, which employs an array of multiple optical-true-time-delay elements and circular antennas array (CAAs). A constructive Fourier series theory about CAAs collectively forming an OAM radio beam is demonstrated. An optical spectrum processor offers the four lines high-resolution time delay by adding a series of linear optical phase shifts. The OAM radio beam with topological charge L=1 is produced and measured successfully.

Postcompensation for nonlinearity of Mach-Zehnder modulator in radio-over-fiber system based on second-order optical sideband processing.

A postcompensation technique for nonlinearity of a Mach-Zehnder modulator in a radio-over-fiber (ROF) system is proposed and experimentally demonstrated based on second-order optical sideband processing and optical carrier band attenuation. The phase of the second-order optical sideband is shifted to suppress the third-order intermodulation distortion (IMD3) in a direct detection ROF link. The optical carrier band is attenuated to make two kinds of origins of IMD3 have equal intensity and cancel each other out. A spurious-free dynamic range of 124.8 dB·Hz(2/3) is achieved, which is about 25 dB more than that without compensation.

Tunable 360° photonic radio frequency phase shifter based on optical quadrature double-sideband modulation and differential detection.

We propose a novel structure of a photonic RF phase shifter based on the vector-sum principle. The optical signal with quadrature double-sideband modulation passes through a dual-output Mach-Zehnder interferometer (MZI), and the two outputs are differentially detected. Two phase-quadrature RF terms are generated, and their amplitudes can be controlled in a triangularly complementary way by changing the phase of the MZI. A full tuning range of 0°-360° at 14 GHz is demonstrated experimentally accompanied by nearly constant RF amplitude. The validity of using our scheme in all-optical RF phase modulation is also verified.

Compensation of dispersion-induced power fading for highly linear radio-over-fiber link using carrier phase-shifted double sideband modulation.

A carrier phase-shifted (CPS) double sideband (DSB) modulation technique in radio-over-fiber (RoF) system is proposed and experimentally demonstrated. By tuning the biases in a single-drive dual parallel Mach-Zehnder modulator (SD-DPMZM), the optical carrier in the DSB spectrum acquires additional phase shift. The transmittance response of a dispersive RoF link is thus being controlled and shifted in the frequency domain. Experiments successfully turned the maximum transmission frequency to 10 GHz and 15 GHz for both 25 and 39 km fiber links. This is also a highly linear scheme, of which a spurious-free dynamic range (SFDR) of 111.3 dB·Hz2/3 is experimentally obtained.