AIM:To investigate the prevalence of visual impairment and its correction status among junior high school students in Xi'an, so as to provide evidence for the development of targeted myopia prevention and control strategies.METHODS: A stratified cluster sampling design was adopted. From March to May 2025, students in grades 7-9 were recruited from three schools in Xi'an, Shaanxi Province, China: Dongfang Middle School, the Middle School Attached to Xi'an University of Technology, and the Xingqing Campus of the High School Affiliated to Xi'an Jiaotong University. In total, 3 974 students were invited, including 1 726 in grade 7, 1 206 in grade 8, and 1 042 in grade 9. The visual acuity was measured monocularly using a 5 m standard logarithmic visual acuity chart, with the fellow eye occluded; the line corresponding to the smallest optotype that could be correctly identified was recorded as the visual acuity value. Non-cycloplegic autorefraction was performed with a desktop autorefractor to obtain spherical equivalent(SE)values for refractive error screening.RESULTS: This study initially included 3 974 students, of whom 32 did not participate in the vision test, resulting in 3 942 students being included in the final analysis. Among them, 3 067(77.80%)were identified with poor vision. The prevalence of myopia was 81.47%(1 746)in males and 87.55%(1 575)in females(P<0.01). A stratified analysis by grade showed myopia rates of 81.72%(1 386)in junior grade one, 84.47%(1 017)in junior grade two, and 88.10%(918)in junior grade three, demonstrating a significant upward trend with increasing grade level(χ2=19.8484, P<0.01). Among the 3 321 myopic students, 2 287 adopted corrective measures. The rates of full correction, under-correction, and non-correction among all myopic students were 48.15%(1 599), 20.71%(688), and 31.14%(1 034), respectively. The rate of non-correction was significantly higher in male students than in females(32.70% vs 29.40%, χ2=4.2222, P<0.05).CONCLUSION: The findings indicate a high prevalence of visual impairment among junior high school students in Xi'an, coupled with suboptimal spectacle-wearing and full-correction rates. There is an urgent need for collaborative efforts across society, schools, and families to implement effective interventions to slow the onset and progression of myopia in this population.

Diabetic Peripheral Neuropathy （DPN） is one of the most common and harmful complications of type 2 diabetes. DPN's pathogenesis include high blood sugar-induced oxidative stress， inflammation， and mitochondrial dysfunction. These factors are combined to damage nerve fibers， leading to sensory issues， pain， and numbness. Through a coordinated effect， these factors trigger nerve fiber damage and lead to sensory abnormalities， pain and numbness in limbs， and other symptoms， seriously restricting patients' activities of daily living and mobility. Recent research highlights that cellular senescence plays a critical role in DPN. Cellular senescence is manifested by the loss of cell proliferation ability， and further aggravates nerve damage via oxidative stress， mitochondrial dysfunction， autophagy impairment， inflammatory reaction， and other mechanisms， accelerating DPN occurrence and progression. In terms of medical treatment， current methods focus on blood sugar control， pain relief medicine， and microcirculation improvement， while no therapy has been developed based on cellular senescence. In contrast， traditional Chinese medicine （TCM） shows a unique advantage in DPN prevention and treatment via cellular senescence modulation. TCM emphasizes a holistic approach， as well as syndrome differentiation and treatment， effective in anti-aging and nerve damage repair. Recent studies show that TCM active ingredients， including puerarin， ginsenosides， and berberine， can reduce inflammation， oxidative stress， and apoptosis via signaling pathway regulation， thereby slowing cellular senescence to alleviate nerve damage. Furthermore， TCM compounds such as Buyang Huanwutang， Taohong Siwutang， and Huangqi Guizhi Wuwutang exert synergistic effects on cellular senescence-related pathways to improve nerve health and reduce DPN clinical symptoms. Therefore， this paper reviews the literature related to the interaction between cellular senescence and DPN from the perspective of cellular senescence， summarizing the mechanism of DPN and TCM intervention strategies.

ObjectiveTo investigate the present situation of input, output, outcome and impact of all registered community-based rehabilitation stations in Inner Mongolia in China, and analyze how the input predict the output, outcome and impact. MethodsFrom March 1st to April 30th, 2025, a questionnaire survey was conducted on all registered community-based rehabilitation stations in Inner Mongolia, covering four dimensions: input, output, outcome and impact. A total of 1 365 questionnaires were distributed. The input included four items: laws and policies, human resources, equipment and facilities, and rehabilitation information management. The output included two items: technical paths and benefits/effectiveness. The outcome included three items: coverage rates, rehabilitation interventions and functional results. The impact included two items: health and sustainability. Each item contained several questions, all of which were described in a positive way. Each question was scored from one to five. A lower score indicated that the situation of the community-based rehabilitation station was more in line with the content described in the question. Regression analysis was performed using the total score of each item of input dimension as independent variables, and the total scores of the output, outcome and impact dimensions as dependent variables. ResultsA total of 1 262 valid questionnaires were collected. The mean values of input, output, outcome and impact of community-based rehabilitation stations were 1.827 to 1.904, with coefficient of variation of 45.892% to 49.239%. The regression analysis showed that, rehabilitation information management, human resources, and laws and policies significantly predicted the output dimension (R² = 0.910, P < 0.001). Meanwhile, all four items in the input dimension predicted both the outcome (R² = 0.850, P < 0.001) and impact dimensions (R² = 0.833, P < 0.001). ConclusionInput, output, outcome and impact of the community-based rehabilitation stations in Inner Mongolia were generally in line with the content of the questions, although some imbalances were observed. Additionally, the input of community-based rehabilitation stations could significantly predict their output, outcome and impact.

ObjectiveTo investigate the effects of Yiqi Wenyang Huoxue Lishui components on the cardiac function and mitochondrial energy metabolism in the rat model of chronic heart failure （CHF） and explore the underlying mechanism. MethodsThe rat model of CHF was prepared by transverse aortic constriction （TAC）. Eight of the 50 SD rats were randomly selected as the sham group， and the remaining 42 underwent TAC surgery. The 24 SD rats successfully modeled were randomized into model， trimetazidine （6.3 mg·kg^-1）， and Yiqi Wenyang Huoxue Lishui components （60 mg·kg^-1 total saponins of Astragali Radix， 10 mg·kg^-1 total phenolic acids of Salviae Miltiorrhizae Radix et Rhizoma， 190 mg·kg^-1 aqueous extract of Lepidii Semen， and 100 mg·kg^-1 cinnamaldehyde） groups. The rats were administrated with corresponding agents by gavage， and those in the sham and model groups were administrated with the same amount of normal saline at a dose of 10 mL·kg^-1 for 8 weeks. Echocardiography was used to examine the cardiac function in rats. Enzyme-linked immunosorbent assay was employed to determine the serum levels of N-terminal pro-B-type natriuretic peptide （NT-ProBNP）， hypersensitive troponin（cTnI）， creatine kinase （CK）， lactate dehydrogenase （LD）， free fatty acids （FFA）， superoxide dismutase （SOD）， and malondialdehyde （MDA）. The colorimetric assay was employed to measure the levels of adenosine triphosphate （ATP）， adenosine diphosphate （ADP）， and adenosine monophosphate （AMP） in the myocardial tissue. The pathological changes in the myocardial tissue were observed by hematoxylin-eosin staining and Masson staining. The Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase activities in the myocardial tissue were determined by the colorimetric assay. The ultrastructural changes of myocardial mitochondria were observed by transmission electron microscopy. Western blot was employed to determine the protein levels of ATP synthase subunit delta （ATP5D）， glucose transporter 4 （GLUT4）， and carnitine palmitoyltransferase-1 （CPT-1）. The mitochondrial complex assay kits were used to determine the activities of mitochondrial complexes Ⅰ， Ⅱ， Ⅲ， and Ⅳ. ResultsCompared with the sham group， the model group showed a loosening arrangement of cardiac fibers， fracture and necrosis of partial cardiac fibers， inflammatory cells in necrotic areas， massive blue fibrotic tissue in the myocardial interstitium， increased collagen fiber area and myocardial fibrosis， destroyed mitochondria， myofibril disarrangement， sparse myofilaments， and fractured and reduced cristae. In addition， the rats in the model group showed declined ejection fraction （EF） and fractional shortening （FS）， risen left ventricular end-diastolic diameter （LVIDd）， left ventricular end-systolic diameter （LVIDs）， left ventricular end-diastolic posterior wall thickness （LVPWd）， left ventricular end-systolic posterior wall thickness （LVPWs）， left ventricular end-diastolic volume （LVVOLd）， and left ventricular end-systolic volume （LVVOLs）， elevated levels of NT-ProBNP， cTnI， CK， MDA， FFA， and LD， lowered level of SOD， down-regulated protein levels of GLUT4 and CPT-1， decreased activities of Na⁺-K⁺-ATPase， Ca²⁺-Mg²⁺-ATPase， and respiratory complexes Ⅰ-Ⅳ， and declined levels of ATP5D， ATP， ADP， and AMP （P<0.05， P<0.01）. Compared with the model group， the Yiqi Wenyang Huoxue Lishui components and trimetazidine groups showed alleviated pathological damage of the mitochondria and mycardial tissue， risen EF and FS， declined LVIDd， LVIDs， LVPWd， LVPWs， LVVOLd， and LVVOLs， lowered levels of NT-ProBNP， cTnI， CK， MDA， FFA， and LD， elevated level of SOD， up-regulated protein levels of GLUT4 and CPT-1， increased activities of Na⁺-K⁺-ATPase， Ca²⁺-Mg²⁺-ATPase， and respiratory complexes Ⅰ-Ⅳ， and elevated levels of ATP5D， ATP， ADP， and AMP （P<0.05， P<0.01）. ConclusionYiqi Wenyang Huoxue Lishui components can improve the cardiac function， reduce myocardial injury， regulate glucose and lipid metabolism， optimize the utilization of substrates， and alleviate the damage of mitochondrial structure and function， thus improving the energy metabolism of the myocardium in the rat model of CHF.

ObjectiveTo explore the protective effect of Shengxiantang on cardiac function and myocardial microvascular injury in rats with chronic heart failure （CHF）. MethodsThe CHF rat model was prepared by aortic arch constriction （TAC）. Of the 72 SD rats， 8 were randomly selected as the sham operation group， where the chest was opened without ligating the aortic arch. The 40 successfully modeled rats were randomly divided into the model group， the Shengxiantang low-， medium-， and high-dose groups （5.1， 10.2， 20.4 g·kg^-1）， and the trimetazidine group （6.3 mg·kg^-1）， with 8 rats in each group. Drug administration began 4 weeks after modeling. The administration groups received the corresponding drugs by gavage， while the sham operation and model groups were given the same amount of distilled water for 8 consecutive weeks. Echocardiography was used to assess cardiac function. Enzyme-linked immunosorbent assay （ELISA） was used to detect the levels of nitric oxide （NO）， endothelin （ET-1）， vascular endothelial growth factor （VEGF）， and von Willebrand factor （vWF）. Ultrastructural changes of microvessels were observed by transmission electron microscopy. Immunohistochemistry was used to detect the expression levels of ATP synthase subunit （ATP5D） and F-actin in myocardial tissue. Western blot was used to detect the expression levels of occludin， claudin， vascular endothelial cadherin （VE-Cadherin）， and zonula occludens-1 （ZO-1）. Microvessel density was measured by immunofluorescence staining. ResultsCompared with the sham operation group， the ejection fraction （EF） and left ventricular shortening fraction （FS） in the model group were significantly decreased （P<0.01）， while the left ventricular diastolic diameter （LVIDd）， left ventricular systolic diameter （LVIDs）， left ventricular end-diastolic posterior wall thickness （LVPWd）， left ventricular end-systolic posterior wall thickness （LVPWs）， left ventricular end-diastolic volume （LVVOLd）， and left ventricular end-systolic volume （LVVOLs） were significantly increased （P<0.01）. The levels of NO and VEGF were significantly decreased （P<0.01）， while the levels of ET-1 and vWF were significantly increased （P<0.01）. Under electron microscopy， the microvascular basement membrane was incomplete and the tight junctions were blurred. The expression levels of ATP5D， F-actin， occludin， claudin， ZO-1， and VE-Cadherin were significantly decreased （P<0.05， P<0.01）， and the relative density of microvessels was significantly reduced （P<0.05， P<0.01）. After intervention with Shengxiantang， the EF and FS of CHF rats significantly increased （P<0.01）， while the LVIDd， LVIDs， LVPWd， LVPWs， LVVOLd， and LVVOLs significantly decreased （P<0.01）. The levels of NO and VEGF significantly increased （P<0.01）， while the levels of ET-1 and vWF significantly decreased （P<0.01）. Under electron microscopy， the microvascular basement membrane was relatively complete and the tight junctions were more continuous. The expression levels of ATP5D， F-actin， occludin， claudin， ZO-1， and VE-Cadherin significantly increased （P<0.05， P<0.01）， and the relative density of microvessels significantly increased （P<0.01）. ConclusionShengxiantang can effectively improve the cardiac function of CHF rats， reduce microvascular endothelial injury， strengthen the connection between endothelial cells， and increase microvessel density， thereby protecting myocardial microvascular injury.

ObjectiveTo explore the protective effect of Shengxiantang on cardiac function and myocardial microvascular injury in rats with chronic heart failure （CHF）. MethodsThe CHF rat model was prepared by aortic arch constriction （TAC）. Of the 72 SD rats， 8 were randomly selected as the sham operation group， where the chest was opened without ligating the aortic arch. The 40 successfully modeled rats were randomly divided into the model group， the Shengxiantang low-， medium-， and high-dose groups （5.1， 10.2， 20.4 g·kg^-1）， and the trimetazidine group （6.3 mg·kg^-1）， with 8 rats in each group. Drug administration began 4 weeks after modeling. The administration groups received the corresponding drugs by gavage， while the sham operation and model groups were given the same amount of distilled water for 8 consecutive weeks. Echocardiography was used to assess cardiac function. Enzyme-linked immunosorbent assay （ELISA） was used to detect the levels of nitric oxide （NO）， endothelin （ET-1）， vascular endothelial growth factor （VEGF）， and von Willebrand factor （vWF）. Ultrastructural changes of microvessels were observed by transmission electron microscopy. Immunohistochemistry was used to detect the expression levels of ATP synthase subunit （ATP5D） and F-actin in myocardial tissue. Western blot was used to detect the expression levels of occludin， claudin， vascular endothelial cadherin （VE-Cadherin）， and zonula occludens-1 （ZO-1）. Microvessel density was measured by immunofluorescence staining. ResultsCompared with the sham operation group， the ejection fraction （EF） and left ventricular shortening fraction （FS） in the model group were significantly decreased （P<0.01）， while the left ventricular diastolic diameter （LVIDd）， left ventricular systolic diameter （LVIDs）， left ventricular end-diastolic posterior wall thickness （LVPWd）， left ventricular end-systolic posterior wall thickness （LVPWs）， left ventricular end-diastolic volume （LVVOLd）， and left ventricular end-systolic volume （LVVOLs） were significantly increased （P<0.01）. The levels of NO and VEGF were significantly decreased （P<0.01）， while the levels of ET-1 and vWF were significantly increased （P<0.01）. Under electron microscopy， the microvascular basement membrane was incomplete and the tight junctions were blurred. The expression levels of ATP5D， F-actin， occludin， claudin， ZO-1， and VE-Cadherin were significantly decreased （P<0.05， P<0.01）， and the relative density of microvessels was significantly reduced （P<0.05， P<0.01）. After intervention with Shengxiantang， the EF and FS of CHF rats significantly increased （P<0.01）， while the LVIDd， LVIDs， LVPWd， LVPWs， LVVOLd， and LVVOLs significantly decreased （P<0.01）. The levels of NO and VEGF significantly increased （P<0.01）， while the levels of ET-1 and vWF significantly decreased （P<0.01）. Under electron microscopy， the microvascular basement membrane was relatively complete and the tight junctions were more continuous. The expression levels of ATP5D， F-actin， occludin， claudin， ZO-1， and VE-Cadherin significantly increased （P<0.05， P<0.01）， and the relative density of microvessels significantly increased （P<0.01）. ConclusionShengxiantang can effectively improve the cardiac function of CHF rats， reduce microvascular endothelial injury， strengthen the connection between endothelial cells， and increase microvessel density， thereby protecting myocardial microvascular injury.

Access to the clinical application of medical technology is one of the core institutional contents of medical quality management， involving medical quality assurance， the achievement of patient safety goals， and medical service satisfaction. Medical technology is only permitted for clinical use after its safety and effectiveness have been verified through clinical research， as well as evaluated and reviewed by the medical technology clinical application management committee and ethics committee of this medical and health institution. Based on the relevant laws， regulations， and ethical principles， combined with the experience of ethical review in the clinical application of medical technology from some medical and health institutions， a thematic discussion was held to formulate ethical review guidelines for the clinical application of medical technology for references. These guidelines elaborated on the management system for access to the clinical application of medical technology in medical and health institutions， the system of ethics committees and the requirements of review norms， technical plans and their review points， key points for the implementation of informed consent， technical teams and conditions， and other aspects.

ObjectiveTo investigate the effects of different concentrations of Shaoyaotang-containing serum on lipopolysaccharide （LPS）-induced inflammation of human colorectal adenocarcinoma （Caco-2） cells by inhibiting apoptosis via activating the tumor necrosis factor （TNF） receptor superfamily member 6 （Fas）/Fas ligand （FasL） pathway. MethodsCaco-2 cells were allocated into blank， model （LPS， 10 mg·L^-1）， Shaoyaotang-containing serum （5%， 10%， 15%， 20%）， and Fas inhibitor （KR-33493， 20 mmol·L^-1） groups. Except the blank group， the other groups were stimulated with 10 mg·L^-1 LPS for 24 h for the modeling of inflammation. After successful modeling， the blank， Fas inhibitor， and model groups were treated with blank serum， and the Shaoyaotang-containing serum groups were treated with the serum samples at corresponding concentrations for 24 h. The Fas inhibitor group was subjected to KR-33493 pretreatment for 1 h. Cell proliferation and viability were examined by the cell-counting kit-8 （CCK-8） method. The levels of interleukin （IL）-6， IL-1β， and TNF-α were measured by enzyme-linked immunosorbent assay. Apoptosis was detected by flow cytometry. The protein and mRNA levels of Fas， FasL， cysteinyl aspartate-specific proteinase （Caspase）-3， Caspase-9， B-cell lymphoma 2 （Bcl-2）， and Bcl-2-associated X protein （Bax） were determined by Western blot and Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， respectively. ResultsCompared with the blank group， the model group presented a decrease in cell survival rate （P<0.01）. Compared with that in the model group， the cell survival rate showed no significant change in the 5% Shaoyaotang-containing serum group but increased in the 10%， 15%， and 20% Shaoyaotang-containing serum groups （P<0.01）. Since there was no statistical difference between the 5% Shaoyaotang-containing serum group and the model group， 10%， 15%， and 20% Shaoyaotang-containing sera were selected for the follow-up study. Compared with the blank group， the model group showed risen levels of IL-6， IL-1β， and TNF-α （P<0.01）， an increased apoptosis rate （P<0.01）， up-regulated protein and mRNA levels of Fas， FasL， Caspase-3， Caspase-9， and Bax （P<0.01）， and down-regulated protein and mRNA levels of Bcl-2 （P<0.01）. Compared with the model group， the Fas inhibitor group and the 10%， 15%， and 20% Shaoyaotang-containing serum groups showed declined levels of IL-6， IL-1β， and TNF-α （P<0.01）， decreased apoptosis rates （P<0.01）， down-regulated protein and mRNA levels of Fas， FasL， Caspase-3， Caspase-9， and Bax （P<0.05， P<0.01）， and up-regulated protein and mRNA levels of Bcl-2 （P<0.05， P<0.01）. In addition， the 15% and 20% Shaoyaotang-containing serum groups had lower levels of IL-6， IL-1β， and TNF-α （P<0.05， P<0.01）， lower apoptosis rates （P<0.05， P<0.01）， lower protein and mRNA levels of Fas， FasL， Caspase-3， Caspase-9， and Bax （P<0.05， P<0.01）， and higher protein and mRNA levels of Bcl-2 （P<0.05， P<0.01） than the 10% Shaoyaotang-containing serum group. ConclusionThe Shaoyaotang-containing serum can reduce the content of inflammatory factors in Caco-2 cells， down-regulate the protein and mRNA levels of Fas， FasL， Caspase-3， Caspase-9， and Bax， and up-regulate the protein and mRNA levels of Bcl-2 under the intervention of LPS by regulating the Fas/FasL pathway and inhibiting the apoptosis of intestinal epithelial cells in ulcerative colitis.

ObjectiveTo investigate the protective effect and mechanism of Shaoyaotang （SYD） on the lipopolysaccharide （LPS）-induced damage of tight junction proteins in the human colorectal adenocarcinoma （Caco-2） cell model of inflammation via the Ras homolog gene family member A （RhoA）/Rho-associated coiled-coil forming protein kinase （ROCK） pathway. MethodsCaco-2 cells were grouped as follows： Blank， model （LPS， 10 mg·L^-1）， SYD-containing serum （10%， 15%， and 20%）， and inhibitor （Fasudil， 25 μmol·L^-1）. After 24 hours of intervention， the cell viability in each group was examined by the cell-counting kit 8 （CCK-8） method. Enzyme-linked immunosorbent assay was employed to determine the levels of endothelin-1 （ET-1）， tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）， and interleukin-6 （IL-6）. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot were employed to determine the mRNA and protein levels， respectively， of RhoA， ROCK2， claudin-5， and zonula occludens-1 （ZO-1） in cells of each group. ResultsCompared with the blank group， the model group showcased a marked reduction in the cell viability （P<0.01）， elevations in the levels of ET-1， TNF-α， IL-1β， and IL-6 （P<0.01）， declines in both mRNA and protein levels of ZO-1 and claudin-5 （P<0.01）， and rises in mRNA and protein levels of RhoA and ROCK2 （P<0.01）. Compared with the model group， the Shaoyaotang-containing serum （10%， 15%， and 20%） groups had enhanced cell viability （P<0.01）， lowered levels of ET-1， TNF-α， IL-1β， and IL-6 （P<0.01）， up-regulated mRNA and protein levels of ZO-1 and claudin-5 （P<0.05， P<0.01）， and down-regulated mRNA and protein levels of RhoA and ROCK2 （P<0.01）. Moreover， the inhibitor group and the 15% and 20% Shaoyaotang-containing serum groups had lower levels of ET-1， TNF-α， IL-1β， and IL-6 （P<0.05， P<0.01）， higher mRNA and protein levels of ZO-1 and claudin-5 （P<0.05， P<0.01）， and lower mRNA and protein levels of RhoA and ROCK2 （P<0.05， P<0.01） than the 10% Shaoyaotang-containing serum group. ConclusionThe Shaoyaotang-containing serum can lower the levels of LPS-induced increases in levels of inflammatory cytokines and endothelin to ameliorate the damage of tight junction proteins of the Caco-2 cell model of inflammation by regulating the expression of proteins in the RhoA/ROCK pathway.

Benign prostatic hyperplasia （BPH） is a common chronic progressive disease in middle-aged and elderly men， characterized by prostate enlargement and bladder outlet obstruction， leading to symptoms such as frequent urination， urgency， and difficulty urinating. The pathogenesis of BPH involves factors such as aging， hormonal metabolic abnormalities， inflammatory responses， and imbalances in cell proliferation and apoptosis. Currently， the main treatment methods for BPH include medication， physical therapy， and surgical intervention. However， medication may cause side effects like sexual dysfunction and hypotension， physical therapy has limited efficacy， and surgery carries risks and postoperative complications. Therefore， there is an urgent need to find safer and more effective treatment options. Traditional Chinese medicine （TCM）， with its focus on treatment based on syndrome differentiation and a holistic approach， offers therapeutic advantages through multiple pathways and mechanisms. Recent studies have shown that TCM regulates pathways such as phosphoinositide-3-kinase/protein kinase B （PI3K/Akt）， nuclear factor-κB （NF-κB）， mitogen-activated protein kinases （MAPK）， nuclear factor E₂-related factor 2/antioxidant response element （Nrf2/ARE）， androgen receptor （AR）， transforming growth factor-β （TGF-β）/Smad， and hypoxia-inducible factor-1α/vascular endothelial growth factor （HIF-1α/VEGF） to inhibit oxidative stress and inflammatory response， reduce prostate cell proliferation， and promote apoptosis， thus exerting therapeutic effects. This article summarizes and analyzes the roles of these signaling pathways in the occurrence and development of BPH and the mechanisms of TCM intervention， aiming to provide scientific evidence for clinical treatment and drug development for BPH.