1.The Effect of Modified Ditan Decoction (涤痰汤) on Cognitive Function and Resting-State Functional Magnetic Resonance Imaging of the Brain in Chronic Intermittent Hypoxia Model Rats
Naijie CHEN ; Xiaoting WANG ; Fengsheng XU ; Shuanghong SHEN ; Zuanfang LI ; Qin CHEN ; Jin CHEN ; Runhua WU
Journal of Traditional Chinese Medicine 2025;66(1):71-78
ObjectiveTo explore the effect of modified Ditan Decoction (涤痰汤) on chronic intermittent hypoxia cognitive function and the potential function mechanism. MethodsTwenty-four Sprague-Dawley (SD) rats were randomly divided into a normal group, a model group, and a modified Ditan Decoction group, with eight rats in each group. Rats in the modified Ditan Decoction group were administered the decoction by gavage at 14.8 ml/(kg·d), while the normal group and the model group received the same dose of normal saline. Thirty minutes after daily gavage, the rats in all three groups were placed in an intermittent hypoxia chamber. The oxygen concentration for the model group and the modified Ditan Decoction group was adjusted daily for 8 hours using a computer program to establish the model, while the normal group was exposed to the same airflow rate of ambient air. The intervention was continued for 12 weeks to establish a chronic intermittent hypoxia rat model. The Y-maze test was used to evaluate spatial working memory in the rats. Resting-state functional magnetic resonance imaging (rs-fMRI) was performed to detect whole-brain regional homogeneity (ReHo) and seed-based functional connectivity (FC). Brain regions showing significant differences in rs-fMRI were selected for further analysis. Immunofluorescence was used to detect β-amyloid (Aβ) deposition and the number of ionized calcium-binding adapter molecule 1 (IBA1)-positive microglial cells. Immunohistochemistry was employed to assess the expression of synaptophysin (SYP), the excitatory synapse marker vesicular glutamate transporter 1 (Vglut1), and the inhibitory synapse marker vesicular γ-aminobutyric acid transporter (VGAT). ResultsCompared with the normal group, the model group showed a reduced spontaneous alternation rate in the Y-maze test. The smoothed Z-score standardized regional homogeneity (SzReHo) value in the left entorhinal cortex significantly increased, and the FC value from this seed point to the left basal forebrain significantly reduced. Additionally, the model group exhibited significantly higher Aβ fluorescence intensity and Iba1 positivity in the left entorhinal cortex, decreased expression of SYP, Vglut1, and VGAT, along with an increased Vglut1/VGAT ratio (P<0.05 or P<0.01). Compared to the model group, the modified Ditan Decoction group demonstrated an increased spontaneous alternation rate, a significantly reduced SzReHo value in the left entorhinal cortex, and a significantly increased FC value from this region to the left basal forebrain. Furthermore, this group showed significantly lower Aβ fluorescence intensity and Iba1 positivity in the left entorhinal cortex, increased levels of SYP, Vglut1, and VGAT, and a decreased Vglut1/VGAT ratio (P<0.05 or P<0.01). ConclusionModified Ditan Decoction can reconstruct the projection from the left basal forebrain to the entorhinal cortex in chronic intermittent hypoxia, thereby reducing Aβ aggregation and excessive microglial activation in the left entorhinal cortex. This process improves the excitation/inhibition imbalance caused by synaptic remodeling, ultimately enhancing cognitive function in rats of chronic intermittent hypoxia.
2.Material Basis and Its Distribution in vivo of Qili Qiangxin Capsules Analyzed by UPLC-Q-Orbitrap-MS
Jianwei ZHANG ; Jiekai HUA ; Rongsheng LI ; Qin WANG ; Xinnan CHANG ; Wei LIU ; Jie SHEN
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(5):185-193
ObjectiveBased on ultra-performance liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry(UPLC-Q-Orbitrap-MS), the chemical constituents of Qili Qiangxin capsules was identified, and their distribution in vivo was analyzed. MethodsUPLC-Q-Orbitrap-MS was used to detect the sample solution of Qili Qiangxin capsules, as well as the serum, brain, heart, lung, spleen, liver and kidney tissues of mice after oral administration. Using the Thermo Xcalibur 2.2 software, the compound information database was constructed, and the molecular formulas of compounds corresponding to the quasi-molecular ions were fitted. Based on the information of retention time, accurate relative molecular mass and fragments, the compounds and their distribution in vivo were analyzed by comparing with the data of reference substances and literature. ResultsA total of 233 compounds, including 70 terpenoids, 60 flavonoids, 23 organic acids, 17 alkaloids, 20 steroids, 7 coumarins and 36 others, were identified or predicted from Qili Qiangxin capsules, 73 of which were identified matching with standard substances. Tissue distribution results showed that 71, 17, 38, 33, 32, 58 and 43 migrating components were detected in blood, brain, heart, lung, spleen, liver and kidney, respectively. Thirty-seven components were absorbed into the blood and heart, including quinic acid, benzoylaconitine benzoylmesaconine and so on. Fourteen components were absorbed into the blood and six tissues, including calycosin, methylnissolin, formononetin, alisol B, alisol A and so on. ConclusionThis study comprehensively analyzes the chemical components of Qili Qiangxin capsules and their distribution in vivo. Among them, astragaloside Ⅳ, salvianolic acid B, ginsenoside Rb1, ginsenoside Rb3, ginsenoside Rd, ginsenoside Rg3, calycosin-7-glucoside, and sinapine may be the important components for the treatment of heart failure, which can provide useful reference for its quality control and research on pharmacodynamic material basis.
3.Effect of pegylated interferon-α-2b therapy on cytotoxicity of virus-specific CD8+ T cells in HBeAg-negative patients with chronic hepatitis B virus infection
Lei QIN ; Guangpeng LI ; Peijun SHEN ; Lanfang ZHANG ; Xiaofei YANG ; Meijuan PENG ; Ye ZHANG
Journal of Clinical Hepatology 2025;41(4):628-636
ObjectiveTo investigate the change in the activity of hepatitis B virus (HBV)-specific CD8+ T cells after pegylated interferon-α-2b (PEG-IFN-α-2b) therapy in HBeAg-negative patients with chronic HBV infection. MethodsA total of 53 HBeAg-negative patients with chronic HBV infection who attended The First Affiliated Hospital of Xinxiang Medical University and Tangdu Hospital of Air Force Mdical University from April 2020 to June 2022 were enrolled and treated with PEG-IFN-α-2b (180 μg/week, subcutaneous injection) antiviral therapy. The study endpoint was HBsAg clearance (course of treatment<48 weeks) or 48 weeks (course of treatment≥48 weeks). Peripheral blood mononuclear cells were isolated at baseline and study endpoint, and peripheral blood T cell counts were measured. Enzyme-linked immunospot assay was used to measure the frequency of HBV-specific CD8+ T cells secreting perforin, granzyme B, and interferon-γ. A total of 17 HLA-A*02-restricted patients were selected, and CD8+ T cells were purified to establish direct- and indirect-contact co-culture systems for HBV-specific CD8+ T cells and HepG2.2.15 cells. The level of lactate dehydrogenase in supernatant was measured to calculate the mortality rate of HepG2.2.15 cells, and the levels of HBV DNA, cytotoxic molecules, and cytokines in supernatant were also measured. Flow cytometry was used to measure the expression of apoptosis ligands, and the cytotoxicity of HBV-specific CD8+ T cells was evaluated. The independent samples t-test or the paired t-test was used for comparison of normally distributed continuous data between two groups, and the Mann-Whitney U test or the Wilcoxon rank-sum test was used for comparison of non-normally distributed continuous data between two groups. ResultsThe HBsAg clearance rate at study endpoint was 30.19% (16/53). There were no significant differences in peripheral blood T cell counts (CD3+, CD4+, and CD8+ T cells) between baseline and study endpoint (P>0.05). At study endpoint, there was a significant increase in the frequency of HBV-specific CD8+ T cells secreting perforin, granzyme B, and interferon-γ (U=177.50, t=11.90, U=186.50, all P<0.001), and the patients with HBsAg clearance had a significantly higher frequency of such HBV-specific CD8+ T cells than those without HBsAg clearance (U=120.50, t=2.73, U=121.50, all P<0.01). In the direct- and indirect-contact co-culture systems at study endpoint, HBV-specific CD8+ T cells induced a significant reduction in HBV DNA in the supernatant of HepG2.2.15 cells (all P<0.001) and significant increases in the secretion of interferon-γ and tumor necrosis factor-α (all P<0.05); in the direct-contact co-culture system, HBV-specific CD8+ T cells induced significant increases in the mortality rate of HepG2.2.15 cells (13.62%±3.27% vs 11.39%±2.40%, t=2.27, P=0.030) and the secretion of perforin and granzyme B (t=72.50, U=52.50, both P<0.05). In the direct- and indirect-contact co-culture systems, compared with HBV-specific CD8+ T cells from the patients without HBsAg clearance, the HBV-specific CD8+ T cells from patients with HBsAg clearance had a significantly greater reduction in HBV DNA (P<0.05) and significant increases in the secretion of interferon-γ and tumor necrosis factor-α (P<0.05). ConclusionPEG-IFN-α-2b therapy can help to achieve a relatively high HBsAg clearance rate in HBeAg-negative patients with chronic HBV infection, and the activity of HBV-specific CD8+ T cells is significantly enhanced, which is closely associated with HBsAg clearance.
4.Medical text classification model integrating medical entity label semantics.
Li WEI ; Dechun ZHAO ; Lu QIN ; Yanghuazi LIU ; Yuchen SHEN ; Changrong YE
Journal of Biomedical Engineering 2025;42(2):326-333
Automatic classification of medical questions is of great significance in improving the quality and efficiency of online medical services, and belongs to the task of intent recognition. Joint entity recognition and intent recognition perform better than single task models. Currently, most publicly available medical text intent recognition datasets lack entity annotation, and manual annotation of these entities requires a lot of time and manpower. To solve this problem, this paper proposes a medical text classification model, bidirectional encoder representation based on transformer-recurrent convolutional neural network-entity-label-semantics (BRELS), which integrates medical entity label semantics. This model firstly utilizes an adaptive fusion mechanism to absorb prior knowledge of medical entity labels, achieving local feature enhancement. Then in global feature extraction, a lightweight recurrent convolutional neural network (LRCNN) is used to suppress parameter growth while preserving the original semantics of the text. The ablation and comparison experiments are conducted on three public medical text intent recognition datasets to validate the performance of the model. The results show that F1 score reaches 87.34%, 81.71%, and 77.74% on each dataset, respectively. The results show that the BRELS model can effectively identify and understand medical terminology, thereby effectively identifying users' intentions, which can improve the quality and efficiency of online medical services.
Semantics
;
Neural Networks, Computer
;
Humans
;
Natural Language Processing
5.Clinical effect of Huotujiji prescription on patients with asthenospermia of spleen-kidney yang-deficiency type.
Yi-Li CAI ; Hong-Ping SHEN ; Li WANG ; Jia-Yi SONG ; Ya-Hua LIU ; Yi YU ; Xue-Qin CHEN
National Journal of Andrology 2025;31(9):827-831
OBJECTIVE:
To observe the effectiveness and safety of Huotujiji prescription for patients with asthenospermia of spleen-kidney yang-deficiency.
METHODS:
Patients with spleen-kidney-yang deficiency type of asthenospermia were divided into two groups by randomized control method. The patients in the control group were treated with L-carnitine oral solution alone. And the patients in experimental group were treated with Huotujiji prescription. Semen volume, sperm concentration, PR, TCM symptom score and spouse pregnancy were compared between the two groups before and after treatment.
RESULTS:
A total of 115 patients were included in the study, with 55 in the experimental group and 60 in the control group. In the experimental group, the sperm concentration before and after treatment were (160.71±53.7)×106/mL, (187.19±41.89)×106/mL, and PR were (20.37±9.42)%, (26.7±6.92)%, respectively. PR+NP were (32.06±8.49)% and (34.89±7.25)%. After the treatment, the sperm motility of both groups significantly improved compared to pre-treatment levels (P<0.05). And the experimental group's sperm concentration also showed a significant increase after the treatment (P<0.05). The pregnancy rate of spouses in the control group was 11.67%, which was 29.09% in the experimental group. The pregnancy rate of the spouses in the two groups showed a statistically significant difference (P<0.05). After 12weeks of treatment, the Traditional Chinese Medicine (TCM) symptom scores in the control group did not decrease significantly compared to those before treatment (P> 0.05). In contrast, the TCM symptom scores in the experimental group decreased significantly after treatment (P<0.05). Moreover, compared with the control group, the TCM symptom scores of the experimental group decreased significantly after treatment (P<0.05).
CONCLUSION
Huotujiji prescription can safely and effectively improve the sperm quality and vitality of patients with spleen-kidney-yang deficiency type of asthenospermia, improve the symptoms of patients, and increase the pregnancy rate of their spouses, which is worthy of clinical promotion.
Humans
;
Male
;
Drugs, Chinese Herbal/therapeutic use*
;
Adult
;
Yang Deficiency/drug therapy*
;
Asthenozoospermia/drug therapy*
;
Female
;
Pregnancy
;
Phytotherapy
;
Sperm Motility
;
Young Adult
;
Spleen
;
Treatment Outcome
;
Sperm Count
6.Deep learning algorithms for intelligent construction of a three-dimensional maxillofacial symmetry reference plane.
Yujia ZHU ; Hua SHEN ; Aonan WEN ; Zixiang GAO ; Qingzhao QIN ; Shenyao SHAN ; Wenbo LI ; Xiangling FU ; Yijiao ZHAO ; Yong WANG
Journal of Peking University(Health Sciences) 2025;57(1):113-120
OBJECTIVE:
To develop an original-mirror alignment associated deep learning algorithm for intelligent registration of three-dimensional maxillofacial point cloud data, by utilizing a dynamic graph-based registration network model (maxillofacial dynamic graph registration network, MDGR-Net), and to provide a valuable reference for digital design and analysis in clinical dental applications.
METHODS:
Four hundred clinical patients without significant deformities were recruited from Peking University School of Stomatology from October 2018 to October 2022. Through data augmentation, a total of 2 000 three-dimensional maxillofacial datasets were generated for training and testing the MDGR-Net algorithm. These were divided into a training set (1 400 cases), a validation set (200 cases), and an internal test set (200 cases). The MDGR-Net model constructed feature vectors for key points in both original and mirror point clouds (X, Y), established correspondences between key points in the X and Y point clouds based on these feature vectors, and calculated rotation and translation matrices using singular value decomposition (SVD). Utilizing the MDGR-Net model, intelligent registration of the original and mirror point clouds were achieved, resulting in a combined point cloud. The principal component analysis (PCA) algorithm was applied to this combined point cloud to obtain the symmetry reference plane associated with the MDGR-Net methodology. Model evaluation for the translation and rotation matrices on the test set was performed using the coefficient of determination (R2). Angle error evaluations for the three-dimensional maxillofacial symmetry reference planes were constructed using the MDGR-Net-associated method and the "ground truth" iterative closest point (ICP)-associated method were conducted on 200 cases in the internal test set and 40 cases in an external test set.
RESULTS:
Based on testing with the three-dimensional maxillofacial data from the 200-case internal test set, the MDGR-Net model achieved an R2 value of 0.91 for the rotation matrix and 0.98 for the translation matrix. The average angle error on the internal and external test sets were 0.84°±0.55° and 0.58°±0.43°, respectively. The construction of the three-dimensional maxillofacial symmetry reference plane for 40 clinical cases took only 3 seconds, with the model performing optimally in the patients with skeletal Class Ⅲ malocclusion, high angle cases, and Angle Class Ⅲ orthodontic patients.
CONCLUSION
This study proposed the MDGR-Net association method based on intelligent point cloud registration as a novel solution for constructing three-dimensional maxillofacial symmetry reference planes in clinical dental applications, which can significantly enhance diagnostic and therapeutic efficiency and outcomes, while reduce expert dependence.
Humans
;
Deep Learning
;
Algorithms
;
Imaging, Three-Dimensional/methods*
;
Male
;
Female
;
Maxilla/diagnostic imaging*
;
Adult
7.Berg Balance Scale score is a valuable predictor of all-cause mortality among acute decompensated heart failure patients.
Yu-Xuan FAN ; Jing-Jing CHENG ; Zhi-Qing FAN ; Jing-Jin LIU ; Wen-Juan XIU ; Meng-Yi ZHAN ; Lin LUO ; Guang-He LI ; Le-Min WANG ; Yu-Qin SHEN
Journal of Geriatric Cardiology 2025;22(6):555-562
OBJECTIVE:
To investigate possible associations between physical function assessment scales, such as Short Physical Performance Battery (SPPB) and Berg Balance Scale (BBS), with all-cause mortality in acute decompensated heart failure (ADHF) patients.
METHODS:
A total of 108 ADHF patients were analyzed from October 2020 to October 2022, and followed up to May 2023. The association between baseline clinical characteristics and all-cause mortality was analyzed by univariate Cox regression analysis, while for SPPB and BBS, univariate Cox regression analysis was followed by receiver operating characteristic curves, in which the area under the curve represented their predictive accuracy for all-cause mortality. Incremental predictive values for both physical function assessments were measured by calculating net reclassification index and integrated discrimination improvement scores. Optimal cut-off value for BBS was then identified using restricted cubic spline plots, and survival differences below and above that cut-off were compared using Kaplan-Meier survival curves and the log-rank test. The clinical utility of BBS was measured using decision curve analysis.
RESULTS:
For baseline characteristics, age, female, blood urea nitrogen, as well as statins, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, or angiotensin receptor-neprilysin inhibitors, were predictive for all-cause mortality for ADHF patients. With respect to SPPB and BBS, higher scores were associated with lower all-cause mortality rates for both assessments; similar area under the curves were measured for both (0.774 for SPPB and 0.776 for BBS). Furthermore, BBS ≤ 36.5 was associated with significantly higher mortality, which was still applicable even adjusting for confounding factors; BBS was also found to have great clinical utility under decision curve analysis.
CONCLUSIONS
BBS or SPPB could be used as tools to assess physical function in ageing ADHF patients, as well as prognosticate on all-cause mortality. Moreover, prioritizing the improvement of balance capabilities of ADHF patients in cardiac rehabilitation regimens could aid in lowering mortality risk.
8.Mechanism of Reactive Oxygen/Nitrogen Species in Liver Ischemia-Reperfusion Injury and Preventive Effect of Chinese Medicine.
Lei GAO ; Yun-Jia LI ; Jia-Min ZHAO ; Yu-Xin LIAO ; Meng-Chen QIN ; Jun-Jie LI ; Hao SHI ; Nai-Kei WONG ; Zhi-Ping LYU ; Jian-Gang SHEN
Chinese journal of integrative medicine 2025;31(5):462-473
Liver ischemia-reperfusion injury (LIRI) is a pathological process involving multiple injury factors and cell types, with different stages. Currently, protective drugs targeting a single condition are limited in efficacy, and interventions on immune cells will also be accompanied by a series of side effects. In the current bottleneck research stage, the multi-target and obvious clinical efficacy of Chinese medicine (CM) is expected to become a breakthrough point in the research and development of new drugs. In this review, we summarize the roles of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in various stages of hepatic ischemia-reperfusion and on various types of cells. Combined with the current research progress in reducing ROS/RNS with CM, new therapies and mechanisms for the treatment of hepatic ischemia-reperfusion are discussed.
Reperfusion Injury/drug therapy*
;
Reactive Oxygen Species/metabolism*
;
Reactive Nitrogen Species/metabolism*
;
Humans
;
Liver/drug effects*
;
Animals
;
Medicine, Chinese Traditional
;
Drugs, Chinese Herbal/pharmacology*
9.Pien Tze Huang Attenuates Cell Proliferation and Stemness Promoted by miR-483-5p in Hepatocellular Carcinoma Cells.
Li-Hui WEI ; Xi CHEN ; A-Ling SHEN ; Yi FANG ; Qiu-Rong XIE ; Zhi GUO ; Thomas J SFERRA ; You-Qin CHEN ; Jun PENG
Chinese journal of integrative medicine 2025;31(9):782-791
OBJECTIVE:
To investigate the effect of miR-483-5p on hepatocellular carcinoma (HCC) cells proliferation and stemness, as well as the attenuating effect of Pien Tze Huang (PZH).
METHODS:
Differentially expressed miRNA between HepG2 cells and hepatic cancer stem-like cells (HCSCs) were identified by a miRNA microarray assay. miR-483-5p mimics were transfected into HepG2 cells to explore the effects of miR-483-5p on cell proliferation and stemness. HepG2 cells and HCSCs were treated with PZH (0, 0.25, 0.50 and 0.75 mg/mL) to explore the effects of PZH on the proliferation and stemness, both in non-induced state and the state induced by miR-483-5p mimics.
RESULTS:
miR-483-5p was significantly up-regulated in HCSCs and its overexpression increased cell proliferation and stemness in HepG2 cells (P<0.05). PZH not only significantly inhibited proliferation in HepG2 cells, but also significantly suppressed the cell proliferation and self-renewal of HCSCs (P<0.05). The effects of miR-483-5p mimics on proliferation and stemness of HepG2 cells were partially abolished by PZH.
CONCLUSIONS
miR-483-5p promotes proliferation and enhances stemness of HepG2 cells, which were attenuated by PZH, demonstrating that miR-483-5p is a potential molecular target for the treatment of HCC and provide experimental evidence to support clinical use of PZH for patients with HCC.
Humans
;
MicroRNAs/metabolism*
;
Cell Proliferation/drug effects*
;
Liver Neoplasms/drug therapy*
;
Carcinoma, Hepatocellular/drug therapy*
;
Hep G2 Cells
;
Neoplastic Stem Cells/metabolism*
;
Drugs, Chinese Herbal/therapeutic use*
;
Gene Expression Regulation, Neoplastic/drug effects*
10.Application of Gas Chromatography Ion Mobility Spectrometry Technology Combined with Chemometric Methods in Identification of Foeniculi Fructus from Haiyuan Region
Xiurong TIAN ; Hao WANG ; Kejing PANG ; Penglong YU ; Xia LIU ; Mengyue SHEN ; Xianglin JIANG ; Yonghua LI ; Zhihong LI ; Hongqiong DING ; Qin YANG ; Xingying LI ; Qian XIONG ; Guochao WAN ; Yuexiang MA ; Zhenping LIU
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(17):184-192
ObjectiveTo establish a geographical origin identification model for Foeniculi Fructus from Haiyuan, providing a new technical reference for the protection of Haiyuan's geo-authentic medicinal materials and its designation as a national geographical indication agricultural product. MethodsSamples of Foeniculi Fructus were collected from eight producing areas, including Minqin (Gansu), Bozhou (Anhui), Qingdao (Shandong), Dezhou (Shandong), Urumqi (Xinjiang), Nujiang (Yunnan), Gutuo (Inner Mongolia), and Haiyuan (Ningxia). Gas chromatography-ion mobility spectrometry (GC-IMS) was used to detect the volatile organic compounds (VOCs) in samples from these geographic origins. VOCs were qualitatively analyzed through dual matching with the National Institute of Standards and Technology (NIST) mass spectral database and the IMS drift time database. Using the Reporter module and Gallery Plot visualization tools within the LAV analytical platform, VOC fingerprint profiles characterizing geographic origins were constructed. A non-targeted analytical strategy was adopted, and 97 VOCs detected via GC-IMS were subjected to principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) based on their differential distribution patterns to construct an origin identification model for Foeniculi Fructus from Haiyuan region. Key discriminative markers were screened using variable importance in projection (VIP) values greater than 1. ResultsA total of 97 VOCs were identified, including alcohols, aldehydes, ketones, esters, organic acids, terpenoids, ethers, alkenes, and benzenes. The PLS-DA model, based on VOCs data obtained by GC-IMS, effectively distinguished Foeniculi Fructus in Haiyuan region from those of other origins. During cross-validation, the model achieved a prediction parameter (Q2) of 0.976 and a goodness-of-fit parameter (R2) of 0.936, with no overfitting observed in permutation testing. Twelve key flavor markers with VIP > 1 were identified as characteristic indicators of Haiyuan origin. ConclusionA stable and highly predictive origin identification model for Foeniculi Fructus from Haiyuan was successfully established using GC-IMS technology, PLS-DA, and VIP-based marker screening. This model provides a novel technical strategy for accurately distinguishing Foeniculi Fructus in Haiyuan region from other regional varieties and offers new technical support for its protection as a geo-authentic medicinal material and a nationally designated geographical indication agricultural product in China.

Result Analysis
Print
Save
E-mail