1.Advances in perioperative nutritional management for patients with esophageal cancer
Zuyu ZHANG ; Bo YANG ; Rong NIU ; Jijun XUE ; Jian CHEN ; Dong LI ; Wentao ZHAO ; Wenfeng HAN ; Yue BAI
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(01):157-162
Esophageal cancer is a prevalent malignant tumor of the digestive tract in China, and radical surgery remains the cornerstone of its comprehensive treatment. However, multifactorial challenges such as postoperative gastrointestinal tract reconstruction, traumatic stress, and tumor-related metabolic disturbances render esophageal cancer patients highly susceptible to malnutrition. Perioperative nutritional support therapy plays a crucial role in enhancing surgical safety, improving clinical outcomes, and elevating patients' quality of life by regulating metabolic homeostasis, preserving organ function, and optimizing the immune microenvironment. This article reviews the mechanisms underlying malnutrition in esophageal cancer, methods for nutritional status assessment, and precision intervention pathways based on multi-omics evaluations. The aim is to strengthen clinicians' awareness of standardized perioperative nutritional management for esophageal cancer patients and promote its clinical implementation, thereby facilitating postoperative recovery and improving long-term quality of life.
2.The feasibility of using high-definition thoracoscopy to identify sympathetic ganglia during thoracic sympathicotomy for primary palmar hyperhidrosis
Gang XU ; Chaoyue HU ; Cong CHEN ; Yuancai LIN ; Daolong ZHU ; Han LIU ; Dong WANG
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(04):578-583
Objective To explore the feasibility of using high-definition thoracoscopy to identify sympathetic ganglia during thoracic sympathicotomy for primary palmar hyperhidrosis. Methods The clinical data of patients with primary palmar hyperhidrosis who underwent high-definition thoracoscopic sympathicotomy in Taikang Xianlin Drum Tower Hospital from June to July 2023 were retrospectively analyzed. Intraoperative visualization rates and anatomical variations of sympathetic ganglia were recorded, and the consistency between white-light thoracoscopy and near-infrared fluorescence imaging was compared. Additionally, surgical videos from previous fluorescence-guided procedures were reviewed. Results Finally 100 patients were collected, including 54 females and 46 males, with an average age of (21.92±6.56) years. All patients underwent endoscopic thoracic sympathicotomy at R3 level. The overall intraoperative ganglion visualization rate was 92.5% (740/800), with G2-G5 rates of 95.5% (191/200), 94.0% (188/200), 94.0% (188/200), and 86.5% (173/200), respectively. Ganglion variations occurred in 32.0% (237/740), predominantly at G3 (29.8%) and G4 (42.6%). In 5 indocyanine green-enhanced patients, the concordance rate between white-light and near-infrared fluorescence imaging was 100.0% (38/38). Video analysis of 14 near-infrared fluorescence-guided surgeries demonstrated a 99.1% (107/108) consistency rate. Postoperative palmar hyperhidrosis improvement reached 100.0% (100/100) with no Horner’s syndrome. Conclusion With the wide clinical application of high-definition thoracoscopy, accurate thoracic sympathicotomy has the feasibility of clinical application.
3.Compact Fundus Imaging System Using Shack-Hartmann Wavefront Sensing for High-speed Auto-focus
Zhe-Kai LIN ; Long CHEN ; Geng-Yong ZHENG ; Jin-Tian HUANG ; Jia-Xin DONG ; Shang-Pan YANG ; Wen-Zheng DING ; Ding-An HAN ; Xue-Hua WANG ; Ya-Guang ZENG
Progress in Biochemistry and Biophysics 2026;53(4):1076-1086
ObjectiveThe widespread adoption of portable fundus cameras for primary care and community screening is hindered by limitations in current autofocus(AF) technologies. Image-based methods relying on sharpness evaluation require iterative searches, resulting in slow convergence, while projection-based techniques are susceptible to optical artifacts and calibration errors. To address these challenges, this study introduces a novel AF system based on direct wavefront sensing, designed to deliver simultaneous high speed, high precision, and operational robustness within the compact form factor essential for portable ophthalmic devices. MethodsOur approach fundamentally reimagines the AF process by directly measuring the ocular wavefront aberration. We developed a custom portable fundus camera integrating a miniaturized Shack-Hartmann wavefront sensor (SHWS) into the optical path. An 850 nm laser diode projects a point source onto the retina via oblique illumination to minimize corneal reflections. Light scattered from this spot carries the eye’s refractive error through the imaging optics and is directed to the SHWS, positioned at a plane optically conjugate to the primary color CMOS imaging sensor. A microlens array within the SHWS samples the incident wavefront, generating a pattern of focal spots on a CCD. Real-time centroid analysis of these spots provides a map of local wavefront slopes. These measurements are processed through a singular value decomposition (SVD) algorithm to fit a Zernike polynomial basis set, enabling real-time reconstruction of the wavefront phase. The defocus component (S) is extracted from the second-order Zernike coefficients, providing a direct, quantitative measure of the refractive error in diopters. This value serves as a precise error signal in a closed-loop control system, which commands a voice-coil actuated focusing lens to its null position in a single, deterministic step, eliminating the need for iterative search algorithms. ResultsComprehensive evaluation demonstrated the system’s high performance. Testing on a calibrated model eye (OEMI-7) established a highly linear relationship between the computed defocus S and the focusing lens position across a ±20 Diopter (D) compensation range, achievable within a 5 mm mechanical travel. The system achieved a focusing precision of 0.08 D, corresponding to an 18-fold improvement over a conventional projection spot-size method tested under identical conditions. The total focus acquisition time, encompassing wavefront measurement, computation, and lens actuation, averaged under 0.5 s. Clinical validation with 25 human volunteers (50 eyes, refractive range -15 D to +10 D) confirmed practical efficacy. The wavefront-sensing AF succeeded in 92% of attempts with a mean time of 0.5 s, substantially outperforming a projection-based benchmark which achieved only a 32% success rate with an average time of 4.25 s. The system provided instantaneous directional guidance and maintained stability during minor ocular movements. Objective assessment of image quality, via amplitude contrast of retinal vasculature, showed consistent and significant enhancement following AF correction across the entire tested diopter range. ConclusionThis work successfully implements and validates a direct wavefront-sensing autofocus paradigm for portable fundus cameras. By directly quantifying and compensating for the optical defocus aberration, this method bypasses the fundamental limitations of image-processing and projection-based techniques, enabling rapid, precise, and deterministic diopter compensation. The developed system delivers an exceptional combination of a wide operational range (±20 D), high accuracy (0.08 D), fast convergence (0.5 s), and a compact physical footprint. This technology provides a practical and high-performance focusing solution capable of enhancing the reliability, throughput, and diagnostic utility of portable retinal imaging in large-scale screening applications. Future efforts will be directed towards system cost optimization and performance adaptation for diverse ocular conditions.
4.Confirmatory analysis of HBsAg reactive samples from voluntary blood donors
Qiaolin ZHANG ; Fang WANG ; Dong LIU ; Fengjiao HAN ; Liu LI ; Xiaochuan ZHENG ; Xuelian DENG ; Dongyan YANG
Chinese Journal of Blood Transfusion 2026;39(4):452-457
Objective: To systematically analyze the confirmatory positivity of different combinations of HBsAg screening results in blood testing, providing data to support the optimization of blood donor eligibility management. Methods: A retrospective analysis was conducted on blood screening data from 174 266 voluntary blood donor samples at the Chongqing Blood Center between October 2021 and September 2022. Samples with inconsistent results between the two HBsAg enzymelinked immunosorbent assays (ELISA) and individual donor nucleic acid testing (NAT) were confirmed using an electrochemiluminescence immunoassay (ECLIA) and a neutralization test. The detection efficacy of four different HBsAg ELISA reagents was compared using the HBsAg-confirmed positive samples. Results: A total of 767(0.44%) HBV-reactive (HB-sAg and/or HBV DNA reactive) samples were detected. Among them, 344 samples with discordant serological and NAT results were collected, of which 64(18.6%) were confirmed positive by neutralization test. Additionally, 5 samples that were neutralization-negative but double-reactive for HBsAg and HBV DNA were confirmed as positive according to FDA guidance, resulting in a total of 69(20.1%) confirmed HBsAg-positive samples. There were significant differences in the neutralization test confirmation rates among different screening result categories (P<0.05): The group with dual HBsAg reagent reactivity (double reactive) & NAT-negative had the highest confirmation rate (96.9%, 31/32); the group reactive to only reagent 2 (single reactive) had a rate of 25.7% (29/113); while the confirmation rates for samples reactive to only reagent 1 and samples with isolated HBV DNA positivity were extremely low [0(0/34) and 2.4%(4/165), respectively]. The four commercial reagents showed significant differences in their ability to detect confirmed positive samples that were initially single reactive (P<0.05). Conclusion: Given the performance variations among HBsAg screening reagents, thorough performance verification is essential before implementation. When NAT is negative, dual HBsAg reactivity in screening can serve as a basis for confirming infection and directly deferring blood donors. However, confirming infection in donors with single HBsAg reactivity is more challenging, necessitating supplementary tests to rule out infection risk.
5.Construction of a community-family management model for older adults with mild cognitive impairment
Junli CHEN ; Han ZHANG ; Yefan ZHANG ; Yanqiu ZHANG ; Runguo GAO ; Qianqian GAO ; Weiqin CAI ; Haiyan LI ; Lihong JI ; Zhiwei DONG ; Qi JING
Chinese Journal of Rehabilitation Theory and Practice 2026;32(1):90-100
ObjectiveTo develop a community-family management model for older adults with mild cognitive impairment (MCI) and to formulate detailed application specifications, and to fully leverage the initiative of communities and families under limited resource conditions, for achieving community-based early detection and early intervention for older adults with MCI. MethodsA systematic literature review was conducted to identify pertinent publications. Corpus-based research methodologies were employed to extract, refine, integrate and synthesize management elements, thereby establishing the specific content and service processes for each stage of the management model. Utilizing the 5W2H analytical framework, essential elements such as management stakeholders, target populations, content and methods for each stage were delineated. The model and its application guidelines were finalized through expert consultation and demonstration. ResultsAn expert evaluation of the management model yielded mean scores of 4.84, 4.32 and 4.84 for acceptability, feasibility and systematicity, respectively. By integrating the identified core elements with expert ratings and feedback, the final iteration of the community-family management model for older adults with MCI was formulated. This model comprised of five stages: screening and identification, comprehensive assessment, intervention planning, monitoring and referral pathways to ensure implementation, and enhanced support for communities, family members and caregivers. Additionally, it included 18 specific application guidelines. ConclusionThe proposed management model may theoretically help delay cognitive decline, improve cognitive function and potentially promote reversal from MCI to normal cognition. It may also enhance the awareness and coping capacity of older adults and their families, strengthen community healthcare professionals' ability to early identify and manage MCI.
6.Stress Accelerates Depressive-Like Behaviors through Increase of Notch2 Expression in N141I Mutation Presenilin-2 Transgenic Mice
Seung Sik YOO ; Sun Mi GU ; Kyung Tak NAM ; Jeong Soon CHOI ; Yong Sun LEE ; In Jun YEO ; Ji Eun YU ; Sanghyeon KIM ; Dong Won LEE ; Hyeon Joo HAM ; Ju Young CHANG ; Jaesuk YUN ; Dong Ju SON ; Sang-Bae HAN ; Jin Tae HONG
Biomolecules & Therapeutics 2026;34(3):544-555
Alzheimer’s disease (AD) is characterized by progressive cognitive deterioration and significant depression. However, the mechanisms linking depression to AD pathology remain unclear. Here, we investigated whether Notch2 signaling mediates depressionlike behaviors in presenilin-2 (PS2) N141I mutant mice, an early-onset AD model. PS2 wild-type (WT) and mutant (MT) mice aged 12-15 months were subjected to unpredictable chronic mild stress (UCMS) for 4 weeks, followed by sucrose preference, tail-hanging, and forced swimming tests. Behavioral assessments showed that UCMS exacerbated anhedonia and immobility only in PS2 MT mice. Molecular analysis revealed concomitant increases in plasma corticosterone, hippocampal γ-secretase activity, and Notch2 expression, and elevated total and phosphorylated glucocorticoid receptor levels in PS2 MT-UCMS mice. Gene expression profiling of human hippocampal datasets confirmed upregulation of NOTCH2 in Alzheimer’s disease and depression.Pharmacological inhibition of γ-secretase and Notch signaling with DAPT normalizes depressive behavior, reduces corticosterone release, attenuates GR phosphorylation, and inhibits Notch2 signaling in PS2 MT mice. These findings identify Notch2 as a pivotal mediator linking chronic stress to molecular changes associated with depression and AD, and suggest that targeting Notch2 signaling may provide therapeutic benefits for comorbid mood and neurodegenerative disorders.
7.Association between Obesity and Melanoma Risk in an Asian Population: A Nationwide Cohort Study
Hye Yeon KOO ; Kyungdo HAN ; Jihye PARK ; Jinhyung JUNG ; Seonghye KIM ; Hyeonjin CHO ; In Young CHO ; Dong Wook SHIN
Cancer Research and Treatment 2026;58(2):677-685
Purpose:
Previous studies from mostly Western populations have suggested possible associations between obesity and melanoma risk. This study aimed to investigate associations between obesity status and melanoma using a nationwide cohort of Koreans.
Materials and Methods:
A total of 4,441,403 adults who received a national health examination in 2012 were included from the Korean National Health Insurance Service database, and followed until December 31, 2022. Obesity status was defined based on the body mass index at the baseline health examination. Cox proportional hazards analyses were performed to evaluate associations between obesity status and incident melanoma, with adjustment for confounders. Stratified analyses were performed by sex and menopausal status (in women).
Results:
Overall, melanoma risk increased according to obesity status (p for trend=0.024); adjusted hazard ratios (95% confidence intervals) for melanoma risk were 0.766 (0.438–1.340) in underweight; 1.292 (1.072–1.557) in overweight; 1.202 (1.002–1.442) in obesity; and 1.191 (0.798–1.778) in severe obesity compared to normal weight (reference). In stratified analyses, similar trends to those of the overall study population were observed among men and premenopausal women (p for trend=0.052 in men and 0.036 in premenopausal women). Among premenopausal women, the risk of melanoma increased linearly with obesity status. Meanwhile, among postmenopausal women, melanoma risk showed no significant difference or trend according to obesity status.
Conclusion
Overweight and obesity were associated with increased risk of melanoma in a population-based cohort of Koreans. Obese individuals, especially men and premenopausal women, may require more thorough prevention and screening strategies for melanoma.
8.Mechanisms of Huanglian Jiedutang and Its Major Active Constituents in Inhibiting LPS-induced M1 Polarisation of BV2 Microglia
Haojia ZHANG ; Kai WANG ; Kunjing LIU ; Xin LAN ; Zijin SUN ; Chunyu WANG ; Wenyuan MA ; Wei SHAO ; Jinhua HAN ; Liyang DONG ; Changxiang LI ; Xueqian WANG ; Youxiang CUI ; Fafeng CHENG ; Qingguo WANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(11):44-55
ObjectiveTo investigate whether Huanglian Jiedutang (HLJD) and its major active constituents (geniposide, baicalin, and berberine) can inhibit the inflammatory response of BV2 cells under lipopolysaccharide (LPS) stimulation via the high-mobility group protein B1 (HMGB1)/Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway, and to explore differences in therapeutic efficacy among the three monomers, their combined formula, and HLJD under equal content ratios. MethodsBV2 microglial cells were used as the primary experimental model. Cell viability was assessed using the cell counting kit-8 (CCK-8) method to examine the effects of different concentrations of dimethyl sulfoxide (DMSO, 0.8%, 0.4%, 0.2%, 0.1%, and 0.05%) on cell viability. IncuCyte was employed to monitor the growth of cells under different concentrations of HLJD (200, 100, 50, 25, 12.5, 6.25 mg·L-1). Nitric oxide (NO) assay was used to screen the optimal HLJD concentration. High-performance liquid chromatography (HPLC) determined the content of geniposide, baicalin, and berberine in HLJD, and experimental groups were subsequently established according to the relative proportions of these constituents. CCK-8 assay evaluated cell viability under different treatments. Enzyme-linked immunosorbent assay (ELISA) measured levels of inflammatory factors (TNF-α, IL-1β, IL-6, IL-10) in the supernatant. Flow cytometry assessed the effects of treatments on M1-type polarization of BV2 cells. Western blot determined the expression levels of HMGB1, TLR4, and NF-κB-related proteins. ResultsCompared with the blank group, DMSO at concentrations ≤0.2% did not affect cell viability within 48 h. BV2 cell growth plateaued at 24 h after treatment with 200 mg·L-1 HLJD. Under stimulation with 2 mg·L-1 LPS, this concentration of HLJD effectively reduced NO release, and 6 h pre-treatment had a stronger inhibitory effect on NO than direct administration. HPLC results showed that 1 mg of HLJD freeze-dried powder contained approximately 24 μg of geniposide, 15 μg of baicalin, and 30 μg of berberine. Based on these ratios, experimental groups were blank, LPS (2 mg·L-1), HLJD (200 mg·L-1), monomer combination, geniposide (4.8 mg·L-1), baicalin (3 mg·L-1), and berberine (6 mg·L-1). The monomer combination group consisted of all three active constituents dissolved together. LPS and HLJD or its active constituents did not affect cell viability compared with the blank group. LPS significantly increased TNF-α, IL-1β, IL-6, and IL-10 in the supernatant (P<0.01). HLJD and its active constituents significantly reduced pro-inflammatory factors TNF-α, IL-1β, and IL-6 (P<0.05, P<0.01) while upregulating anti-inflammatory IL-10 (P<0.01), with the monomer combination showing the strongest effect (P<0.05, P<0.01). Compared with the blank group, LPS significantly increased the proportion of CD80⁺CD86⁺ (M1-type) BV2 cells (P<0.01). HLJD and its constituents partially inhibited M1 polarization (P<0.05, P<0.01), with the monomer combination exhibiting the most pronounced effect (P<0.05, P<0.01). Compared with the blank group, LPS upregulated HMGB1, TLR4, and NF-κB-related proteins (P<0.01), whereas HLJD and its active constituents significantly reduced their expression (P<0.05, P<0.01), with the monomer combination having the strongest regulatory effect (P<0.05, P<0.01). ConclusionHLJD and its major active constituents (geniposide, baicalin, berberine) can inhibit LPS-induced inflammatory responses in BV2 cells. The combination of the three active constituents demonstrates the most potent anti-inflammatory effect, significantly attenuating M1-type polarization of BV2 cells via the HMGB1/TLR4/NF-κB signaling pathway.
9.Effect of Modifed Huanglian Wendantang on Oxidative Stress in Metabolic Syndrome
Xinyu DONG ; Yi HAN ; Yubo HAN ; Li LIU
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(20):153-161
ObjectiveTo observe the effect of modified Huanglian Wendantang on oxidative stress in metabolic syndrome. MethodsA total of 180 patients with metabolic syndrome treated in the outpatient clinics and wards of the First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine from October 2023 to May 2025 were enrolled in this study. According to the randomized numerical table method, the patients were assigned into two groups (90 cases). The basic treatment of the two groups was the same, and the observation group was additionally treated with modified Huanglian Wendantang. The course of treatment was 3 months. The two groups were compared in terms of traditional Chinese medicine (TCM) efficacy, obesity degree [waist circumference (WC), body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR)], blood pressure indicators [systolic blood pressure (SBP) and diastolic blood pressure (DBP)], lipids and glucose indicators [total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting insulin (FINS), fasting glucose (FPG), 2-hour postprandial glucose (2 h PG), and glycosylated hemoglobin (HbA1c)], insulin resistance indicators [homeostatic model assessment for insulin resistance (HOMA-IR), triglyceride-glucose index (TYG index), triacylglycerol-to-high-density lipoprotein cholesterol (TG/HDL) ratio], oxidative stress indicators [malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT), and reactive oxygen species (ROS)], and the safety of treatment. ResultsIn terms of TCM efficacy, the treatment in the observation group was significantly effective in 46 cases, effective in 30 cases, and ineffective in 10 cases, with the total effective rate of 88.4%. The treatment in the control group was significantly effective in 33 cases, effective in 28 cases, and ineffective in 23 cases, with the total effective rate of 72.6%. The observation group had higher total effective rate than the control group (χ2=11.26,P<0.05). After treatment, both groups showed declined levels of WC, BMI, WHR, WHtR, SBP, DBP, TC, TG, LDL-C, FPG, FINS, 2 h PG, HbA1c, HOMA-IR, TG/HDL ratio, TYG index, MDA, and ROS and elevated levels of HDL-C, SOD, GSH, GSH-Px, and CAT (P<0.05). After treatment, the observation group showed lower levels of WC, BMI, WHR, WHtR, TC, TG, LDL-C, FPG, FINS, 2 h PG, HbA1c, HOMA-IR, TG/HDL ratio, TYG index, MDA, and ROS and higher levels of HDL-C, SOD, GSH, GSH-Px, and CAT than the control group (P<0.05). However, after treatment, there was no significant difference in SBP or DBP between the observation group and the control group. No significant adverse reactions were observed in either group. ConclusionModified Huanglian Wendantang can significantly alleviate metabolic syndrome symptoms and reduce oxidative stress, exhibiting antioxidant effects. Moreover, it does not induce adverse reactions, demonstrating safety.
10.Meta-analysis of the efficacy and safety of CD19 CAR-T cell therapy versus standard treatment for relapsed/refractory diffuse large B-cell lymphoma
LEI Qi1 ; MA Chendong2 ; XIONG Shufeng1 ; SUN Yu1 ; HAN Linlin1 ; GU Zhenyang3 ; DONG Lili1
Chinese Journal of Cancer Biotherapy 2026;33(5):563-569
[摘 要] 目的:系统评价CD19 CAR-T细胞免疫疗法对比标准治疗在复发/难治性弥漫性大B细胞淋巴瘤(R/R DLBCL)患者中疗效与安全性,通过探索性分析探索不同CAR-T细胞产品对疗效的潜在影响,为临床治疗决策提供循证参考。方法:计算机检索中国知网、万方数据库、维普期刊数据库、中国生物医学文献数据库、PubMed、Embase和Cochrane Library数据库,搜集CD19 CAR-T细胞疗法对比标准治疗用于R/R DLBCL的随机对照试验(RCT),检索时限均为建库至2025年10月25日。由2位研究者独立进行文献筛选、数据提取和质量评价,采用R4.2.2软件进行Meta分析。结果:共纳入2项Ⅲ期RCT研究(ZUMA-7、TRANSFORM),各结局指标均根据异质性检验结果选择固定效应模型合并数据。疗效方面,CD19 CAR-T细胞疗法可显著改善患者无事件生存期(HR=0.455,95%CI:0.363~0.570,P < 0.001)和降低死亡风险(HR = 0.738,95%CI:0.575~0.947,P = 0.017);同时可显著提高完全缓解率(RR = 1.879,95%CI:1.574~2.242,P < 0.001)。按产品类型的探索性分析显示,liso-cel和axi-cel均优于标准治疗(liso-cel:HR = 0.380,95%CI:0.260~0.540,P < 0.001;axi-cel:HR = 0.510,95%CI:0.380~0.680,P < 0.001),但该分析为不同试验间的对比,证据等级有限。安全性结局显示:CAR-T细胞疗法的免疫效应细胞相关神经毒性综合征(ICANS)发生率显著升高(RR = 22.387,95%CI:4.353~115.132,P < 0.001);≥3级细胞因子释放综合征(CRS)发生率数值升高(RR = 8.181,95%CI:0.935~71.574,P = 0.058),差异无统计学意义。纳入研究的偏倚风险整体为低;敏感性分析证实结果稳健。结论:基于2项RCT的Meta分析结果,CD19 CAR-T细胞(liso-cel/axi-cel)可作为R/R DLBCL二线治疗的选择之一,其疗效优于标准治疗,且特征性不良反应(CRS/ICANS)经规范管理后可控,可根据患者基线状态个体化选择CAR-T细胞产品。本研究证据基础薄弱,上述结论尚需更多高质量、大样本RCT验证。

Result Analysis
Print
Save
E-mail