Static and Dynamic Filler-Associated Tear Trough Deformities: Manifestations and Treatment Algorithm.

BACKGROUND: Fillers are popular substances for the correction of tear trough deformity. Despite well-documented complications increasing gradually, standardized treatment algorithm for deformity secondary to improper injection is still limited. METHODS: Between April 2020 and April 2023, a total of 22 patients with filler-associated tear trough deformity with static bulges or dynamic swells after injection of tear trough were enrolled. For patients who received hyaluronic acid (HA) and unknown fillers, hyaluronidase dissolution was performed. For patients who received non-HA fillers and unknown fillers that failed to dissolve, a magnetic resonance imaging (MRI) examination was conducted. Surgical approaches were selected based on the filler distribution and the condition of the lower eyelid. Ligament releasement and fat transposition were accomplished when fillers were excised. Aesthetic outcomes were evaluated by double-blind examiners using the Global Aesthetic Improvement Scale after patients were followed up. RESULTS: In total, the study included 3 patients with simple static deformities, 1 patient with simple dynamic, and 18 patients with both. Fourteen patients underwent transconjunctival surgery and 8 patients underwent transcutaneous surgery, among which 18 patients underwent hyaluronidase dissolution and 8 patients underwent MRI prior to surgery. A total of 4 patients with self-limited complications recovered after conservative treatment. 90.9% of patients expressed satisfaction or high satisfaction with the treatment results. CONCLUSION: Filler-associated tear trough deformities could be classified into static and dynamic deformities, which could appear separately or simultaneously. Treatment of deformities should be based on characteristics of fillers, in which MRI could serve as a promising tool. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Rationale for immune checkpoint inhibitors plus targeted therapy for advanced renal cell carcinoma.

Renal cell carcinoma (RCC) is a frequent urological malignancy characterized by a high rate of metastasis and lethality. The treatment strategy for advanced RCC has moved through multiple iterations over the past three decades. Initially, cytokine treatment was the only systemic treatment option for patients with RCC. With the development of medicine, antiangiogenic agents targeting vascular endothelial growth factor and mammalian target of rapamycin and immunotherapy, immune checkpoint inhibitors (ICIs) have emerged and received several achievements in the therapeutics of advanced RCC. However, ICIs have still not brought completely satisfactory results due to drug resistance and undesirable side effects. For the past years, the interests form researchers have been attracted by the combination of ICIs and targeted therapy for advanced RCC and the angiogenesis and immunogenic tumor microenvironmental variations in RCC. Therefore, we emphasize the potential principle and the clinical progress of ICIs combined with targeted treatment of advanced RCC, and summarize the future direction.

Vulvar migration of injected polyacrylamide hydrogel following breast augmentation: a case report and literature review.

BACKGROUND: Vulvar migration is a rare complication of filler injection for breast augmentation, generally presenting as repeated pain and fever. We will report a case of woman with polyacrylamide hydrogel breast injection develops vulvar abscess. CASE PRESENTATION: A woman with a history of polyacrylamide hydrogel breast injection was noted to have vulvar abscess due to migration of filler materials. Filler removal surgery and vacuum sealing drainage was performed for this patient. The patient was discharged from the hospital with no further complications. After a review of pertinent literature, only four previous case reports are found. Local inflammatory response, infection, large volume injections, inframammary fold destruction, hematogenous or lymphatic migrate, trauma, gravity and external pressure could play essential parts in the migration of injected filler. CONCLUSION: Polyacrylamide hydrogel migration poses a worldwide challenge, necessitating personalized solutions. Our case study underscores the importance of comprehensive examinations for individuals with a history of filler breast injection when suspecting vulvar filler migration.

Constricted posterior fourchette deformities: Definition, classification and surgical treatment.

BACKGROUND: Labiaplasty is one of the top cosmetic procedures patients are seeking in the past two years. However, treatment of disease in posterior fourchette caused by various etiological factors was less investigated and neglected. METHODS: Three types of posterior fourchette deformity were proposed: (1) Redundant posterior fourchette, (2) Relaxed posterior fourchette, and (3) Constricted posterior fourchette. Local flap transfer technique was applied. Y-V-plasty and 5-Z-Flap-plasty were used to treat web type and tight type of the constricted posterior fourchette, respectively. Follow-ups were arranged on the Internet or at the outpatient clinic. Visual analogue scale (VAS) was utilized to evaluate sexual discomfort in the satisfaction questionnaires during follow-up. RESULTS: A total of 48 patients with constricted posterior fourchette deformity from May 2022 to May 2023 were reviewed in the study. Y-V-plasty could decrease VAS in patients with web-type deformity by 4.13 ± 1.46 (p＜0.001). 5-Z-Flap-plasty could decrease VAS in patients with tight-type deformity by 3.76 ± 1.53 (p＜0.05). Satisfaction rates of the web type and tight type were 93.1% (27/29) and 86.7% (13/15) respectively. Complications include two cases of hematoma, one case of persistent pain and two cases of dehiscence. CONCLUSION: Constricted posterior fourchette seriously affects the quality of life. Y-V-plasty and 5-Z-Flap-plasty can be utilized to treat the two subtypes of constricted posterior fourchette, which can effectively reduce the pain score of patients with high satisfaction and few long-term complications.

Patterned Au@Ag nanoarrays with electrically stimulated laccase-mimicking activity for dual-mode detection of epinephrine.

Epinephrine (EP) is a crucial neurotransmitter in the central nervous system. However, an abnormal level of EP in biological fluids can lead to various diseases. Therefore, it is essential to rapidly and accurately detect EP content. Herein, electrically stimulated patterned Au@Ag nanoarrays with laccase-mimicking activity were designed for the dual-mode detection of EP concentration. The patterned Au@Ag nanoarrays exhibit excellent electrochemical properties and electrically stimulated laccase-mimicking activity. They provide sensitive electrochemical responses for detecting EP content. Simultaneously, the Au@Ag nanoarrays can catalyze the oxidation of EP, enabling its detection through a colorimetric process. This dual-mode approach achieves the detection of EP content over a wide linear range of 0.5-200 µM, with a low detection limit of 0.152 µM. Furthermore, the utility of these nanoarrays for sensing EP in human serum was evaluated. This work provides a convenient method using patterned nanozyme array for the visible, rapid and accurate detection of EP content. It provides the important implication for the development of portable and reliable on-site analytical instruments.

Clay mineral nanostructures regulate sequestration of organic carbon in typical fluvial sediments.

The association between clay minerals and organic carbon is pivotal for understanding transport, burial, and preservation processes of sedimentary organic carbon. However, fine-scale microscopic studies are still limited in assessing the effect of diverse clay mineral structures and properties on organic carbon sequestration. In this study, we employed X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy coupled with energy dispersive spectroscopy and electron energy loss spectroscopy analyses to investigate the nanoscale interaction between clay minerals and organic carbon of two typical fluvial sediment samples with contrasting clay mineral compositions and organic carbon origins. Sample from Taiwan shows abundant illite and chlorite with petrogenic organic carbon, while sample from Luzon has significant smectite with pedogenic organic carbon. We observed that the nanostructure of the clay minerals controls the distribution of organic carbon. In the Luzon sample, the organic carbon is tightly associated with smectite, occupying expandable interlayer spaces. In the Taiwan sample, however, the organic carbon is primarily confined on the surface and edge of illite. These findings offer valuable insights into the selective association of organic carbon with clay minerals and underscore the role of clay mineral nanolayer structures in governing the occurrence and preservation of organic carbon in sediments. A comprehensive understanding of these interactions is crucial for accurate assessments of carbon cycling and sequestration in the natural environment.

Comprehensive aesthetic corrections of gynecomastia using the reproducible safe and minimally invasive surgical strategy.

BACKGROUND: Minimally invasive access and fast recovery are trends of gynecomastia surgery. We placed great importance on liposuction and modified original pull-through technique. The purpose of this study was to present a refined surgical strategy for gynecomastia in grade I and II. METHODS: The refined strategy embraced enhanced liposuction to remove the intraglandular fat sufficiently, followed by open resection of gland using the pull-through and bottom-up technique with adjuvant liposuction in the end. Surgical data were recorded and satisfactory questionnaires with 5-point scales were administered during follow-up. RESULTS: Between January 2017 and May 2022, 165 patients underwent enhanced liposuction combined with the pull-through and bottom-up technique for gland excision. Age ranged from 12 to 56 years. The median length of surgery was 100 min. A median of 300 ml of fat was aspirated and a median of 20.8 g of gland was excised. Seventy-seven patients (46.7%) responded the questionnaires at least 6 months postoperatively, and the average overall satisfaction was 4.68 ± 0.52 points. Thirteen sides of breasts developed complications with a rate of 4.0%. CONCLUSION: Enhanced liposuction combined with pull-through and bottom-up technique proved effective to treat grade I and II gynecomastia with minimal scarring and high satisfaction. The refined strategy was simple and safe, and would obtain optimal outcomes even for inexperienced surgeons.

Re-recognition of the role of roughness in keloid assessment.

BACKGROUND: Under visual observation, keloids are more rough than normal skin. This roughness may be used to assess the activity and severity of keloids but lacks the support of objective and accurate evidence. The purpose of this study was to verify the role of roughness in the development of keloids and to clarify the advantage of roughness in the comprehensive assessment of keloids. METHODS: Patients with keloids who attended Peking Union Medical College Hospital were recruited. Keloids were classified into progressive, stable, and atrophic stages based on the change in size over the past year and blood perfusion. The keloids were evaluated using the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS). The roughnesses of the keloid and normal skin were measured using the Phaseshift Rapid In vivo Measurement Of the Skin (PRIMOS), and blood perfusion was measured using laser speckle contrast imaging (LSCI). RESULTS: Thirty-three patients with a total of 81 keloids were included. The surface roughness values Sa, Sq, and Sz of the keloid region were 243.70 (143.85-328.05), 316.20 (179.85-475.20), and 1708.20 (1098.30-4087.20), respectively, which were 4.87, 4.80, and 3.08 times higher than those of normal skin. There were significant differences in roughness among the different keloid stages. A significantly strong correlation between roughness and other assessed indices was found. CONCLUSIONS: Roughness as a morphological characteristic is of great value in the evaluation of keloids. It is recommended as an important examination for keloids.

Astrocytic expression of Yes-associated protein (YAP) regulates retinal neovascularization in a mouse model of oxygen-induced retinopathy.

Pathological neovascularization is the hallmark of many vascular oculopathies. There is still a great deal of uncertainty surrounding retinal neovascularization research. A working hypothesis that astrocytic Yes-associated protein (YAP) act as a key factor in retinal neovascularization was proposed. And our study was conducted to verified this hypothesis. In vivo, we successfully generated mice deficient in YAP in astrocytes (YAPf/f GFAP-Cre mice) and set up oxygen-induced retinopathy (OIR) model. Pathological neovascularization was evaluated by immunofluorescence staining and western blotting. In vitro, cultured retinal astrocytes were transfected with YAP siRNA. Enzyme-linked immunosorbent assay (ELISA) and western blot were used to determine the proteins in the supernatants and cells. The results showed that YAP was upregulated and activated in the OIR mice retinas. Conditional ablation of YAP aggravated pathological neovascularization, along with the upregulation of vascular endothelial growth factor A (VEGF-A) and monocyte chemoattractant protein-1 (MCP-1). Studies in vitro confirmed that the knockdown of YAP in astrocytes lead to increases in VEGF-A and MCP-1 levels, thus enhancing pro-angiogenic capability of YAP-deficit astrocytes. In conclusion, astrocytic YAP alleviates retinal pathological angiogenesis by inhibiting the over-activation of astrocytes, which suppresses excessive VEGF-A production and neuroinflammation.

Differences in Molecular Structure between Vitrinite and Inertinite and Their Impact on Coal Conversion and Utilization.

To compare the differences in chemical structure between vitrinite and inertinite and their effects on transformation and utilization, this paper separated vitrinite and inertinite from three parent coal samples (high-volatile bituminous coal (Rmax (%) = 0.65), medium-volatile bituminous coal (Rmax (%) = 1.25), and low-volatile bituminous coal (Rmax (%) = 1.7)), and the differences in chemical structure were analyzed from three aspects: aromatic structure, aliphatic structure, and cross-linking structure. The molecular structure model of a single maceral was constructed, and the chemical bond parameters and the impact on coal conversion and utilization were analyzed. The results showed that (i) in the same sample, inertinite has advanced evolution characteristics, higher aromaticity, and ring condensation degree, but vitrinite has a faster evolution rate than inertinite. (ii) The molecular structure model shows that with the increase of the evolution degree of samples, the proportion of polycyclic aromatic hydrocarbons increased gradually. After molecular dynamics simulations, the cross-linked structures in the planar macromolecular structure have huge torsion deformation, and the torsion of aromatic structure decreased from benzene, naphthalene, anthracene, and phenanthrene. (iii) The analysis of chemical bond parameters showed that the ether-oxygen bond with shorter bond length and higher bond energy is a key factor hindering the breakage recombination of the macromolecular structure. In the high-evolution stage, the ether carbon content in inertinite is higher than that in vitrinite and has a stronger cross-linking structure. Therefore, it is less reactive in the transformation processes of coking and gasification. However, inertinite has larger aromatic layers and a more ordered orientation, which has certain advantages in the preparation of coal-based graphite.

TSTA3 overexpression promotes malignant characteristics in LUSC by regulating LAMP2-mediated autophagy and tumor microenvironment.

BACKGROUND: TSTA3 gene encoding GDP-L-fucose synthase has recently been proved to be closely related to the prognosis of patients with various tumors. However, its role in lung cancer is still unclear. The purpose of this study is to explore the expression level, prognostic effect, potential function and mechanism of TSTA3 in lung cancer. METHODS: Based on TCGA database, Kaplan-Meier and COX regression was used to analyze the relationship between TSTA3 expression and prognosis of lung cancer patients. Immunohistochemistry was used to determine the TSTA3 protein expression in lung cancer and normal tissues. The function of TSTA3 in lung squamous cell carcinoma (LUSC) cell was determined by CCK8, colony formation, transwell assay in vitro and subcutaneous xenografts in vivo. Transcriptome analysis, Lyso-Tracker Red staining and rescue experiment were used to explore the possible underlying mechanism. RESULTS: The expression of TSTA3 was significantly increased in lung cancer, especially in LUSC, and was significantly correlated with the malignant characteristics of LUSC. COX regression analysis showed that the high expression of TSTA3 was an independent prognostic factor in LUSC patients. This was also confirmed by immunohistochemical staining. Compared with the control group, the proliferation, colony formation, invasion and migration ability of LUSC cells with TSTA3 overexpression was enhanced. Similarly, the ability of cell proliferation, colony formation, invasion and migration were weakened after transient knockdown of TSTA3. In vivo experiment showed that compared with control group, TSTA3 overexpression significantly promoted the growth of tumor and shortened survival time. In addition, transcriptome sequencing analysis showed that the differentially expressed genes between TSTA3 overexpression and control group was mainly concentrated in the lysosome pathway. Further study found that TSTA3 might affect the proliferation, invasion and migration of LUSC by regulating the expression of lysosome-associated membrane protein 2 (LAMP2) in LUSC. CONCLUSION: The expression level of TSTA3 in LUSC is significantly higher than that in normal tissues. High expression of TSTA3 is associated with poor prognosis of LUSC patients. TSTA3 may affect the proliferation, invasion and migration of LUSC by regulating LAMP2.

High-efficient production of L-homoserine in Escherichia coli through engineering synthetic pathway combined with regulating cell division.

L-Homoserine is an important amino acid as a precursor in synthesizing many valuable products. However, the low productivity caused by slow L-homoserine production during active cell growth in fermentation hinders its potential applications. In this study, strategies of engineering the synthetic pathway combined with regulating cell division were employed in an L-homoserine-producing Escherichia coli strain for efficiently biomanufacturing L-homoserine. First, the flux-control genes in the L-homoserine degradation pathway were omitted to redistribute carbon flux. To drive more carbon flux into L-homoserine production, the phosphoenolpyruvate-pyruvate-oxaloacetate loop was redrawn. Subsequently, the cell division was engineered by using the self-regulated promoters to coordinate cell growth and L-homoserine production. The ultimate strain HOM23 produced 101.31 g/L L-homoserine with a productivity of 1.91 g/L/h, which presented the highest L-homoserine titer and productivity to date from plasmid-free strains. The strategies used in this study could be applied to constructing cell factories for producing other L-aspartate derivatives.

Microbial production of L-methionine and its precursors using systems metabolic engineering.

L-methionine is an essential amino acid with versatile applications in food, feed, cosmetics and pharmaceuticals. At present, the production of L-methionine mainly relies on chemical synthesis, which conflicts with the concern over serious environmental problems and sustainable development goals. In recent years, microbial production of natural products has been amply rewarded with the emergence and rapid development of system metabolic engineering. However, efficient L-methionine production by microbial fermentation remains a great challenge due to its complicated biosynthetic pathway and strict regulatory mechanism. Additionally, the engineered production of L-methionine precursors, L-homoserine, O-succinyl-L-homoserine (OSH) and O-acetyl-L-homoserine (OAH), has also received widespread attention because they can be catalyzed to L-methionine via a high-efficiently enzymatic reaction in vitro, which is also a promising alternative to chemical route. This review provides a comprehensive overview on the recent advances in the microbial production of L-methionine and its precursors, highlighting the challenges and potential solutions for developing L-methionine microbial cell factories from the perspective of systems metabolic engineering, aiming to offer guidance for future engineering.

A Review on Pretreatment and Analysis Methods of Polyether Antibiotics in Complex Samples.

Polyether antibiotics (PAs) are the anti-coccidiosis drugs used for treating and preventing coccidiosis. Studies show the residues of these antibiotics in food cause adversities and threaten human health. PAs thus need robust, rugged, and accurate methods for their analysis. This review encompasses pretreatment and detection methods of PAs in diverse matrices since 2010. Both conventional and developed methods are part of the pretreatments, such as dispersive liquid-liquid microextraction, solid-phase extraction, solid-phase microextraction, solvent front position extraction, QuEChERS (Quick Easy Cheap Effective Rugged and Safe), supercritical fluid extraction, and others. The analysis methods involve liquid chromatography coupled with detectors, sensors, etc. The pros and cons of various techniques for PAs have been discussed and future tendencies are proposed.

Progress of pretreatment and analytical methods for PAs are summarized.Comparisons between different mass analyzers are discussed in detail.Novel materials in microextraction methods are depicted.

Progressive Generalized Skin Laxity in a Young Woman.

A Chinese woman in her late 20s presented with a 20-year history of progressive skin laxity. What is your diagnosis?

Is Breast Magnetic Resonance Imaging Superior to Sonography in Gynecomastia Evaluation and Surgery Planning.

BACKGROUND: Data on the value of magnetic resonance imaging (MRI) in the preoperative evaluation and surgery planning of gynecomastia are limited. The purpose of this study is to reveal MRI features and categories of gynecomastia and compare surgical outcomes following MRI and sonography as well as their diagnostic accuracy. METHODS: The area of the gland and the whole breast on the transverse plane via nipple of MRI were measured to calculate the ratio between them. Areola, mass and branch patterns were categorized to represent three different gynecomastia type on MRI. 183 patients were included, with 38 in MRI group and 145 in sonography group. Diagnostic accuracy was assessed by the level of agreement between preoperative imaging findings and intraoperative observations. Surgical data, patients' satisfaction and complications were compared between the two groups. RESULTS: MRI in 75 gynecomastic breasts demonstrated the average ratio of the gland to the whole breast was 10.6%±13.3%. The most common MRI categories were branch patterns (45.3%). The diagnostic concordance rate of MRI was higher than sonography (100% vs. 86.8%, p = 0.001). Among those junior surgeons, the length of surgery was reduced in MRI group (100 min vs. 115 min, p = 0.048). There was no difference in terms of patient's satisfaction and complication rate between MRI and sonography. CONCLUSION: MRI was superior to sonography in diagnostic accuracy to assess the tissue components of gynecomastia and provided informative guidance especially for junior surgeons. Surgical outcomes were comparable regardless of the use of MRI or sonography for evaluation. LEVEL OF EVIDENCE IV: IThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Identification of ferroptosis-associated biomarkers in Stanford type A aortic dissection based on machine learning.

BACKGROUND: Stanford type A aortic dissection (STAAD) is a serious cardiovascular disease with a high mortality rate. Ferroptosis is closely associated with various diseases, including cardiovascular disease. However, the role of ferroptosis in the progression of STAAD remains unclear. METHODS: Gene expression profiles of GSE52093, GSE98770, and GSE153434 datasets were downloaded from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA), least absolute shrinkage and selection operator (LASSO), and support vector machine-recursive feature elimination (SVM-RFE) were performed to determine the ferroptosis-associated characteristic genes in STAAD. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy. Furthermore, immune cell infiltrations were analyzed using the CIBERSORT algorithm. Drug sensitivity analysis was conducted based on the CellMiner database. RESULTS: A total of 65 differentially expressed ferroptosis-associated genes were screened. DAZAP1 and GABARAPL2 were identified as valuable diagnostic biomarkers for STAAD. A nomogram with high accuracy and reliability was constructed as a diagnostic tool for STAAD. Furthermore, immune infiltration analysis suggested that monocytes were higher in the STAAD group compared with the control group. DAZAP1 was positively correlated with monocytes, whereas GABARAPL2 was negatively correlated with monocytes. Pan-cancer analysis showed that DAZAP1 and GABARAPL2 were closely associated with the prognosis of various cancers. In addition, some antitumor drugs might be useful for the treatment of STAAD. CONCLUSION: DAZAP1 and GABARAPL2 might serve as potential diagnostic biomarkers for STAAD. Meanwhile, DAZAP1 and GABARAPL2 might be related to cancer and STAAD in terms of ferroptosis, which provides insights into developing new therapeutic approaches for STAAD.

Standardized Photography of Female Genitalia and Anatomical Evaluations.

BACKGROUND: Standardized photographic recording and anatomic evaluation are crucial to refined and comprehensive preoperative design and enhanced aesthetic effect of female genital cosmetic surgery. OBJECTIVES: The authors aim to propose a standard photographic scheme and physical examination form for the anatomical assessment of patients undergoing female genital surgery. METHODS: The scheme containing 2 positions (standing and lithotomy positions) and 11 views (1 frontal and 2 oblique views from standing position; 6 frontal views with labia minora open and closed, pulled to the opposite side, clitoral hood pushed up, posterior fourchette stretched; 2 oblique views from lithotomy position) (2P11V) is applied to record pre- and postoperative appearance of the vulva. The evaluation form is utilized to record characteristics of different anatomical subunits during photography. RESULTS: Two hundred forty-five patients who underwent female genital surgery were enrolled in the research from October 2018 to October 2022. All the patients received preoperative and postoperative 2P11V photography with about 5-minutes' shooting time. Various anatomical variations containing hypertrophy and prolapse of mons pubis, redundant types of labia minora and clitoral hood, incremental exposure of clitoral glans, hypo- to hypertrophy of labia majora, disappearance of interlabial groove, hypertrophy of posterior fourchette, and relation of subunits were accurately documented. CONCLUSIONS: 2P11V photographic scheme displays the isolated features of each organ and proportion relation among different parts of vulva. The standard photographic record and physical examination form offer detailed anatomical structure to surgeons and facilitate surgeons to carry out an accurate surgical design, which deserve to be promoted and applied.

Triclosan and related compounds in the environment: Recent updates on sources, fates, distribution, analytical extraction, analysis, and removal techniques.

Triclosan (TCS) has been widely used in daily life because of its broad-spectrum antibacterial activities. The residue of TCS and related compounds in the environment is one of the critical environmental safety problems, and the pandemic of COVID-19 aggravates the accumulation of TCS and related compounds in the environment. Therefore, detecting TCS and related compound residues in the environment is of great significance to human health and environmental safety. The distribution of TCS and related compounds are slightly different worldwide, and the removal methods also have advantages and disadvantages. This paper summarized the research progress on the source, distribution, degradation, analytical extraction, detection, and removal techniques of TCS and related compounds in different environmental samples. The commonly used analytical extraction methods for TCS and related compounds include solid-phase extraction, liquid-liquid extraction, solid-phase microextraction, liquid-phase microextraction, and so on. The determination methods include liquid chromatography coupled with different detectors, gas chromatography and related methods, sensors, electrochemical method, capillary electrophoresis. The removal techniques in various environmental samples mainly include biodegradation, advanced oxidation, and adsorption methods. Besides, both the pros and cons of different techniques have been compared and summarized, and the development and prospect of each technique have been given.

Melatonin in different food samples: Recent update on distribution, bioactivities, pretreatment and analysis techniques.

Melatonin (MLT) plays a significant role on maintaining the basic physiological functions and regulating various metabolic processes in plentiful organisms. Recent years have witnessed an increase in MLT's share in global market with its affluent functions. However, the worrisome quality issues and inappropriate or excessive application of MLT take place inevitably. In addition, its photosensitive properties, oxidation, complex substrate concentration and trace levels leave exact detection of MLT doubly difficult. Therefore, it is essential to exploit precise, sensitive and stable extraction and detection methods to resolve above questions. In this study, we reviewed the distribution and bioactivities of MLT and conducted a comprehensive overview of the developments of pretreatment and analysis methods for MLT in food samples since 2010. Commonly used pretreatment methods for MLT include not only traditional techniques, but also novel ones, such as solid-phase extraction, QuEChERS, microextraction by packed sorbent, solid phase microextraction, liquid phase microextraction, and so on. Analysis methods include liquid chromatography coupled with different detectors, GC methods, capillary electrophoresis, sensors, and so on. The advantages and disadvantages of different techniques have been compared and the development tendency was prospected.