BACKGROUND:Clinical studies suggest that both bone quality and excessive crown-to-implant ratio are factors that affect the success rate of implant surgery,but there is no consensus on how large the crown-to-implant ratio under each bone quality will affect the prognosis of implant repair.OBJECTIVE:To analyze the stress and strain of bone tissue around implant restorations with different crown-to-implant ratios under different bone types after stress loading using three-dimensional finite element method.Combined with the Frost bone mechanics regulation system theory,the physiological limits of bone strain were observed for each bone type within a certain range of crown to implant ratios.METHODS:Cone beam CT data were selected from a patient to establish solid bone block models with four different bone types(class Ⅰ bone:cortical bone thickness 3 mm+dense cancellous bone,class Ⅱ bone:cortical bone thickness 2 mm+relatively dense cancellous bone,class Ⅲ bone:cortical bone thickness 1 mm+relatively low-density cancellous bone,class Ⅳ bone:cortical bone thickness 1 mm+low-density cancellous bone).Implant restorations with five different crown-to-implant ratios(1,1.5,2,2.5,and 3)were created on each bone block model,for a total of 20 models.Vertical and oblique forces were applied to the dental crown to observe the von Mises stress values,strains,and displacement of the cortical and cancellous bones,as well as the degree of implant displacement.RESULTS AND CONCLUSION:(1)In the class Ⅰ bone model,when the crown-to-implant ratio reached 3 under oblique loading,the cortical bone strain exceeded the physiological limit.In the class Ⅱ bone model,under oblique loading,when the crown-to-implant ratio reached 2.5,the cortical bone strain exceeded the physiological limit.In the class Ⅲ bone model,under oblique loading,cortical bone exceeded the physiological limit when the crown-to-implant ratio reached 2.5,while cancellous bone reached the critical physiological limit at 1.In the class Ⅳ bone model,under oblique loading,when the crown-to-implant ratio reached 1.5,2,2.5,and 3,the cortical bone strain exceeded the physiological limit.In the class Ⅳ bone model,all five crown-to-implant ratios of cancellous bone exceeded physiological limits.(2)Under vertical load,the cancellous bone strain exceeded the physiological limit when the crown-root ratio reached 1,2,2.5,and 3 in the class Ⅲ bone model,and when the cancellous bone strain of the five crown-root ratios in the class Ⅳ bone model exceeded the physiological limit.(3)Under oblique or vertical load,the implant displacement of the 20 groups of models did not exceed 100 μm.(4)From the perspective of biomechanics,when patients with insufficient bone height choose implant restoration,the crown-root ratio that class Ⅰ bone can tolerate is up to 2.5 times,the crown-root ratio that class Ⅱ bone can tolerate is up to 2 times,and the crown-root ratio that class Ⅲ and class Ⅳ bones can tolerate is up to 1 times due to excessive strain of cancellous bone;but the crown-root ratio that cortical bone in class Ⅲ bone can tolerate is up to 2 times.Whether class Ⅲ bone can tolerate implant restoration with a high crown-root ratio and whether cancellous bone can tolerate higher strains needs further study.

ObjectiveTo measure the distance from the surface of Fengfu （GV 16） to the deep important bony structures in children aged 4 to 8 years based on CT three-dimensional reconstruction technology， thereby providing imaging reference data for clinical acupuncture safe operations in terms of different age groups and needle insertion angles. MethodsCervical CT image data were collected from healthy children aged 4 to 8 years with five age groups （4-， 5-， 6-， 7-， 8-year-old groups）， 20 cases in each group. The images were imported into Mimics 21.0 software for three-dimensional reconstruction. The straight-line distances from the skin model surface of the Fengfu （GV 16） to the first underlying bony barrier （such as the lower edge of the occipital bone， the posterior arch of the atlas vertebra） were measured at intervals of 5° on both the transverse section （0° ± 35°） and the sagittal section （40° upward to 40° downward on the diagonal）. The correlation between the measured distance， age， and angle was analyzed. ResultsIn the transverse and sagittal sections， the measured distance from the skin surface to the underlying bone of Fengfu （GV 16） at each angle increased with age. In the transverse section， the increase was relatively small within the 0° to 20° angle range， whereas a more pronounced increase was observed when the angle exceeded 20°； at measurement angles of 30° to 35°， the distance of the skin surface to the bone at Fengfu （GV 16） in the 7- and 8-year-old groups was significantly greater than that in the 4-year-old group （P＜0.05）. In the sagittal section， the measured distance from the skin surface to the bone at Fengfu （GV 16） was shortest and changed greatly at oblique upward angles of 15° to 40° within each age group， and increased markedly at near-vertical angles of 0° to 10°； it was longest at oblique downward angles of -40° to -5° and showed relatively gradual changes. ConclusionThis study obtained the imaging distance data from Fengfu （GV 16） to the surrounding bony structures in children aged 4 to 8 years through three-dimensional modeling， finding that this distance has clear age and angle dependence， which can provide quantitative evidence for developing individualized and precise safe acupuncture schemes at Fengfu （GV 16） in pediatric clinical practice.

ObjectiveTo measure the distance from the surface of Fengfu （GV 16） to the deep important bony structures in children aged 4 to 8 years based on CT three-dimensional reconstruction technology， thereby providing imaging reference data for clinical acupuncture safe operations in terms of different age groups and needle insertion angles. MethodsCervical CT image data were collected from healthy children aged 4 to 8 years with five age groups （4-， 5-， 6-， 7-， 8-year-old groups）， 20 cases in each group. The images were imported into Mimics 21.0 software for three-dimensional reconstruction. The straight-line distances from the skin model surface of the Fengfu （GV 16） to the first underlying bony barrier （such as the lower edge of the occipital bone， the posterior arch of the atlas vertebra） were measured at intervals of 5° on both the transverse section （0° ± 35°） and the sagittal section （40° upward to 40° downward on the diagonal）. The correlation between the measured distance， age， and angle was analyzed. ResultsIn the transverse and sagittal sections， the measured distance from the skin surface to the underlying bone of Fengfu （GV 16） at each angle increased with age. In the transverse section， the increase was relatively small within the 0° to 20° angle range， whereas a more pronounced increase was observed when the angle exceeded 20°； at measurement angles of 30° to 35°， the distance of the skin surface to the bone at Fengfu （GV 16） in the 7- and 8-year-old groups was significantly greater than that in the 4-year-old group （P＜0.05）. In the sagittal section， the measured distance from the skin surface to the bone at Fengfu （GV 16） was shortest and changed greatly at oblique upward angles of 15° to 40° within each age group， and increased markedly at near-vertical angles of 0° to 10°； it was longest at oblique downward angles of -40° to -5° and showed relatively gradual changes. ConclusionThis study obtained the imaging distance data from Fengfu （GV 16） to the surrounding bony structures in children aged 4 to 8 years through three-dimensional modeling， finding that this distance has clear age and angle dependence， which can provide quantitative evidence for developing individualized and precise safe acupuncture schemes at Fengfu （GV 16） in pediatric clinical practice.

BACKGROUND:Clinical studies suggest that both bone quality and excessive crown-to-implant ratio are factors that affect the success rate of implant surgery,but there is no consensus on how large the crown-to-implant ratio under each bone quality will affect the prognosis of implant repair.OBJECTIVE:To analyze the stress and strain of bone tissue around implant restorations with different crown-to-implant ratios under different bone types after stress loading using three-dimensional finite element method.Combined with the Frost bone mechanics regulation system theory,the physiological limits of bone strain were observed for each bone type within a certain range of crown to implant ratios.METHODS:Cone beam CT data were selected from a patient to establish solid bone block models with four different bone types(class Ⅰ bone:cortical bone thickness 3 mm+dense cancellous bone,class Ⅱ bone:cortical bone thickness 2 mm+relatively dense cancellous bone,class Ⅲ bone:cortical bone thickness 1 mm+relatively low-density cancellous bone,class Ⅳ bone:cortical bone thickness 1 mm+low-density cancellous bone).Implant restorations with five different crown-to-implant ratios(1,1.5,2,2.5,and 3)were created on each bone block model,for a total of 20 models.Vertical and oblique forces were applied to the dental crown to observe the von Mises stress values,strains,and displacement of the cortical and cancellous bones,as well as the degree of implant displacement.RESULTS AND CONCLUSION:(1)In the class Ⅰ bone model,when the crown-to-implant ratio reached 3 under oblique loading,the cortical bone strain exceeded the physiological limit.In the class Ⅱ bone model,under oblique loading,when the crown-to-implant ratio reached 2.5,the cortical bone strain exceeded the physiological limit.In the class Ⅲ bone model,under oblique loading,cortical bone exceeded the physiological limit when the crown-to-implant ratio reached 2.5,while cancellous bone reached the critical physiological limit at 1.In the class Ⅳ bone model,under oblique loading,when the crown-to-implant ratio reached 1.5,2,2.5,and 3,the cortical bone strain exceeded the physiological limit.In the class Ⅳ bone model,all five crown-to-implant ratios of cancellous bone exceeded physiological limits.(2)Under vertical load,the cancellous bone strain exceeded the physiological limit when the crown-root ratio reached 1,2,2.5,and 3 in the class Ⅲ bone model,and when the cancellous bone strain of the five crown-root ratios in the class Ⅳ bone model exceeded the physiological limit.(3)Under oblique or vertical load,the implant displacement of the 20 groups of models did not exceed 100 μm.(4)From the perspective of biomechanics,when patients with insufficient bone height choose implant restoration,the crown-root ratio that class Ⅰ bone can tolerate is up to 2.5 times,the crown-root ratio that class Ⅱ bone can tolerate is up to 2 times,and the crown-root ratio that class Ⅲ and class Ⅳ bones can tolerate is up to 1 times due to excessive strain of cancellous bone;but the crown-root ratio that cortical bone in class Ⅲ bone can tolerate is up to 2 times.Whether class Ⅲ bone can tolerate implant restoration with a high crown-root ratio and whether cancellous bone can tolerate higher strains needs further study.

Nonunion of osteoporotic vertebral fractures (OVF), predominantly affecting the elderly, can lead to intractable pain, vertebral collapse, progressive kyphotic deformity, and neurological impairment, significantly compromising patients′ quality of life. There exists considerable debate on diagnosis and management of OVF, encompassing key issues such as clinical diagnosis and staging criteria for nonunion, surgical indications and procedure selection, and postoperative rehabilitation planning. Currently, there lacks standardized clinical guideline and expert consensus on the diagnosis and management of OVF nonunion in China. To address this gap, Minimally Invasive Surgery Group of Chinese Orthopedic Association, Osteoporosis Committee of Chinese Association of Orthopedic Surgeons, Prevention and Rehabilitation Committee for Osteoporosis of Chinese Association of Rehabilitation Medicine and Minimally Invasive Orthopedic Surgery Branch of China Association for Geriatric Care jointly organized domestic experts in spinal surgery, endocrinology, and rehabilitation to formulate the Clinical guideline for the diagnosis and treatment for nonunion of osteoporotic vertebral fractures ( version 2025), based on existing literature and clinical experience and adhering to principles of scientific rigor and practicality. The guideline provided 13 evidence-based recommendations encompassing diagnosis and treatment of OVF nonunion, aiming to standardize its clinical management.

Objective:To analyze the prevalence of human respiratory syncytial virus（RSV）and the evolutionary characteristics of the adhesion glycoprotein（G）gene in Xi'an from 2023 to 2024.Methods:Respiratory specimens were collected from patients with acute respiratory infections in Xi'an between October 2023 to October 2024. RSV nucleic acid screening was performed using real-time fluorescence quantitative PCR；full-length G gene sequencing was conducted on nucleic acid-positive specimens. Genotyping characterization of the obtained sequences was performed using Nextclade v3.10.0 software.Results:A total of 2 548 respiratory tract infection samples were collected，with 104 cases（4.08%，104/2 548）testing positive for RSV. The highest RSV positivity rate was observed in children aged ≤1 year（12.24%，18/147），and significant difference in positivity rates were found among age groups（χ 2=37.868， P<0.001）. Since October 2023，RSV has seen an epidemic peak during January to February 2024，and gradually declined thereafter，with no positive cases from May to September 2024. Among the 43 RSV-positive samples，12 strains were identified as subtype A（all genotype A.D.3），and 31 strains were subtype B（14 genotype B.D.4.1.1 and 17 genotype B.D.E.1）. Conclusion:From October 2023 to October 2024，RSV had an epidemic peak in January and February in Xi＇an，with subtype B being the predominant circulating type.

Objective:To investigate the epidemiological and genetic characteristics of hand, foot and mouth disease (HFMD) caused by coxsackievirus A6 (CVA6) in Xi′an city from 2021 to 2023.Methods:Collected clinical cases of HFMD, epidemiological information and samples were obtained. The specimens were tested by the real-time RT-PCR for enterovirus A71(EVA71), CVA16, CVA6 and CVA10, respectively. The VP1 regions of CVA6 were amplified and sequenced, MEGA X was used for phylogenetic analysis.Results:From 2021 to 2023, a total of 1 393 HFMD samples were collected, 1 106 (79.40%, 1 106/1 393) of which were positive for enteroviruses. The proportions of EVA71, CVA16, CVA6 and CVA10 were 0.45% (5/1 106), 16.64% (184/1 106), 72.42% (801/1 106) and 2.17% (24/1 106). A total of 801 HFMD cases tested positive for CAV6, including 783 mild cases and 18 severe cases, mainly in children aged ≤5 years (86.02%, 689/801), with a male/female ratio of 1.49∶1. The composition ratio of CVA6 infection differed with year(χ 2=332.62, P<0.01), and the highest composition ratio of CVA6 was in 2023 (91.01%, 638/701). The nucleotide and amino acid similarities in the VP1 region of Xi′an strains of CVA6 were 92.4%-99.8% and 98.3%-100.0%, respectively. Compared with the CVA6 prototype strain(Gdula), the nucleotide and amino acid similarities in the VP1 region of Xi′an strains were 82.2%-84.0% and 95.4%-96.0%, respectively, and there were 18 amino acid mutations in different degrees. Based on the phylogenetic analysis of VP1 region sequences, the CVA6 strains in Xi′an city from 2021 to 2023 belonged to D3a subtype, and could be divided into two clusters with 18 strains in cluster 1 while two strain in cluster 2. Conclusions:The sub-genotype D3a of CVA6 is the predominant virus causing HFMD in Xi′an city from 2021 to 2023, and there are two transmission chains. The monitoring and prevention of CVA6 should be strengthened.

Objective Fasting hypometabolism regulation technology has broad application potential in long-term space flight and survival in extreme extraterrestrial environments.In-depth research on the substrate conversion of energy metabolism and the formation of new steady states under fasting hypometabolism will provide theoretical basis and experimental data support for formulating effective prolonged fasting application mode.Methods 30 SD rats were randomly divided into control group and fasting group(fasting for 1,2,3,and 5 days).Blood biochemical examination,qRT-PCR,and western blotting were performed to analyze the body weight,blood biochemistry,and expression changes of genes and proteins related to glucose and lipid metabolism during different fasting periods.Results Prolonged fasting significantly reduced the body weight,blood glucose,and triglyceride levels of rats;increased the blood ketone level,and replaced glucose as the main energy substance in the body.There are temporal and tissue-specific changes as a whole.Hepatic and renal gluconeogenesis play major roles respectively during different fasting periods.As the fasting time prolongs,the level of hepatic gluconeogenesis gradually decreases,the content of FFA in the blood increases,the expression level of genes related to fat synthesis decreases,fatty acid oxidation is enhanced,and the expression level of the key gene HMGCS2 for ketone body generation increases.Conclusion During prolonged fasting,there is a significant conversion of glucose-ketone energy supply substrates,and a new steady state of energy metabolism mainly supplied by ketone bodies is formed within 2-5 days of fasting.The body maintains a low metabolic state by regulating changes in key genes in pathways such as glucose and lipid metabolism.

Depressive disorder is a kind of mental disorder characterized by persistent and significant depressed mood, with complex etiology and high recurrence rate. At present, more precise and effective diagnostic and therapeutic approaches are still required. Increasing evidence suggests that hypoxia inducible factor-1 (HIF-1) and related pathways are involved in regulating the development and recovery of depression. HIF-1 enhances neuroplasticity, mitigates neuroinflammatory responses, alleviates oxidative stress, and modulates brain energy metabolism by influencing specific molecules associated with depression. This paper reviews pertinent domestic and international studies, examine the potential mechanisms of HIF-1 in the pathogenesis and progression of depression, and explore antidepressant treatment strategies targeting the HIF-1 signaling pathway. This article provides novel insights into elucidating the pathogenesis of depression and developing innovative therapeutic approaches.

Objective To evaluate the effect of pneumatic logistics transport system(PTS)on the trans-portation efficiency of the transferred samples and the accuracy of the results.Methods The transportation speed,temperature and humidity change of PTS were analyzed by temperature and humidity transmitter.Anti-coagulant samples containing disodium ethylenediaminetetraacetate(EDTA-K2),sodium citrate,lithium hepa-rin and samples containing inert separation gel coagulant were selected.and used respectively for complete blood cell analysis,prothrombin time(PT),activated partial prothrombin time(APTT),troponin T(TnT)and other myocardial markers,as well as the detection of items such as glucose(Glu)and lactate dehydrogen-ase(LDH).According to the transfer mode,they were divided into the manual transfer group and the PTS transfer group,and according to the number of PTS transfers,they were divided into the one-time transfer group,the three-time transfer group and before transfer(control).The differences among each group were statistically analyzed,and 1/3 allowable total error(1/3TEa)was adopted as the criterion for determining the clinical application value.Results There was no statistically significant difference in the changes of tempera-ture and humidity during the transportation process of PTS compared with manual transportation(P＞0.05),but it was significantly faster than manual transportation in terms of transportation time(P＜0.05).Com-pared with before transfer,the differences between the PT,APTT,Glu and LDH items in the one-time trans-fer group and the three-time transfer group were statistically significant(P＜0.01),and their deviations were all much greater than 1/3TEa.However,in the plasma samples,compared with before transport,there were statistically significant differences in Glu and LDH between the one-time transfer group and the three-time transfer group(P＜0.05),but the deviations were all less than 1/3TEa.For the items of TnT,red blood cell count and hematocrit,compared with before transfer,there were statistically significant differences between some groups of the one-time transfer group and the three-time transfer group(P＜0.05),but the deviations were all less than 1/3TEa.Conclusion PTS can significantly improve the transportation efficiency of sam-ples,but it significantly affects the detection of Glu and LDH in plasma samples,which can be improved by u-sing serum sample transportation instead.In addition,PTS also affects the detection of PT and APTT,and it is not recommended to use PTS to transport coagulation specimen.