Objective To explore the characteristics of fluid flow within loaded osteons under different boundary conditions.Methods The COMSOL Multiphysics software was used to establish a three-dimensional(3D)finite element model of osteons with different boundary conditions,and the variation rules of pore pressure and flow velocity of osteons under different inner wall pulsating blood pressures and outer wall elastic constraint conditions were analyzed.Results As the pulsatile blood pressure inside the osteon increased from 0 mmHg(1 mmHg=0.133 kPa)to 300 mmHg,the peak pore pressure within the osteon correspondingly increased from 26 kPa to 68 kPa.As the elastic constraint on the outer wall of osteons changed from being completely elastic to completely constrained,the peak pore pressure within osteons increased from 15 kPa to 26 kPa,and the peak flow velocity increased from 0.04 um/s to 0.07 um/s.Conclusions This study reveals the influence laws of changes in boundary conditions such as the pulsatile blood pressure on the inner wall and the elastic constraint on the outer wall of osteons on fluid flow characteristics within loaded osteons.These findings are conducive to a deeper understanding of the mechanical response mechanisms of bone tissues in both physiological and pathological states,and provide an important theoretical basrs for further researches on bone mechanotransduction.

Objective:To investigate the detection and clinical features of human rhinovirus（HRV）infection in children from the Xiamen area.Methods:A retrospective analysis was conducted on children treated at Xiamen Children's Hospital from November 2021 to October 2022.Thirteen types of multiplex respiratory pathogen detection kits were used to screen for 13 common respiratory pathogens. Clinical data of HRV-positive hospitalized children were collected.Results:（1）Among 8 420 children with acute respiratory infections，HRV had the highest detection rate at 20.40%（1 718/8 420），followed by HMPV（10.12%），H3N2（7.46%），HRSV（6.94%），and HPIV（6.59%）.HRV was detected throughout the year，with the highest proportion in May（18.42%）.（2）Out of 1 718 children with HRV infection，863 cases were hospitalized for pneumonia（50.23%，863/1 718）.The median age of hospitalized children was 2.58（1.07，4.20）years old，with 53.77% under 3 years old.（3）The main clinical manifestations of HRV pneumonia were cough（97.68%，843/863），fever（58.05%，501/863），runny nose（57.01%，492/863），nasal congestion（36.96%，319/863），and wheezing（24.33%，210/843）. The HRV pneumonia co-infection group showed statistically significant differences in fever and hospitalization days compared to the single HRV pneumonia infection group（all P<0.05）.（4）Compared to the common pneumonia group，the severe HRV pneumonia group showed statistically significant differences in fever，runny nose，wheezing and hospitalization days the CRP, PCT, LDH levels, and the number of antibiotic applications after hospitalization（all P<0.05）. Conclusion:HRV infection is detected year-round in Xiamen，pneumonia is common，with children under 3 years old being particularly susceptible.It is important to be alert to mixed infections or severe pneumonia.Clinical treatment should avoid unnecessary antibiotic use，actively and provide appropriate treatment.

The aim of this study is to establish an gene editing method of Mesomycoplasma hyo-pneumoniae(Mhp)based on the homologous recombination principle.The restriction enzyme di-gestion and ligation method combined with gene synthesis were used to construct a shuttle plasmid to achieve replication in both Mhp and Escherichia coli(E.coli).The pGEM?-T vector was used as the skeleton.The oriC sequence of Mhp which can achieve the replication of the plasmid in Mhp was inserted into the vector.Sequences of the Spiroplasma promoter and puromycin resistance gene were then inserted into the above constructed plasmid to screen recombinant clones.The up-stream and downstream homologous arms of p97 were constructed to initiate homologous recombination.The recA gene of E.coli is inserted to improve the efficiency of homologous recom-bination.The obtained shuttle plasmid was then delivered into Mhp by electro-transformation or chemical transformation.A shuttle plasmid,pGEM?-Mhp-oriC-p 97,which can replicate in both Mhp and E.coli was constructed.With the transformation of this plasmid,the carried puromycin gene and recA gene can be expressed,the p97 gene can be edited.Finally,the genetically unstable p97 gene mutant was initially obtained.In this study,a tool for Mhp gene editing based on the principle of homologous recombination was established,which laid a foundation for the develop-ment of tools for studying the pathogenesis of Mhp.

Objective To explore the characteristics of fluid flow within loaded osteons under different boundary conditions.Methods The COMSOL Multiphysics software was used to establish a three-dimensional(3D)finite element model of osteons with different boundary conditions,and the variation rules of pore pressure and flow velocity of osteons under different inner wall pulsating blood pressures and outer wall elastic constraint conditions were analyzed.Results As the pulsatile blood pressure inside the osteon increased from 0 mmHg(1 mmHg=0.133 kPa)to 300 mmHg,the peak pore pressure within the osteon correspondingly increased from 26 kPa to 68 kPa.As the elastic constraint on the outer wall of osteons changed from being completely elastic to completely constrained,the peak pore pressure within osteons increased from 15 kPa to 26 kPa,and the peak flow velocity increased from 0.04 um/s to 0.07 um/s.Conclusions This study reveals the influence laws of changes in boundary conditions such as the pulsatile blood pressure on the inner wall and the elastic constraint on the outer wall of osteons on fluid flow characteristics within loaded osteons.These findings are conducive to a deeper understanding of the mechanical response mechanisms of bone tissues in both physiological and pathological states,and provide an important theoretical basrs for further researches on bone mechanotransduction.

Objective:To investigate the detection and clinical features of human rhinovirus（HRV）infection in children from the Xiamen area.Methods:A retrospective analysis was conducted on children treated at Xiamen Children's Hospital from November 2021 to October 2022.Thirteen types of multiplex respiratory pathogen detection kits were used to screen for 13 common respiratory pathogens. Clinical data of HRV-positive hospitalized children were collected.Results:（1）Among 8 420 children with acute respiratory infections，HRV had the highest detection rate at 20.40%（1 718/8 420），followed by HMPV（10.12%），H3N2（7.46%），HRSV（6.94%），and HPIV（6.59%）.HRV was detected throughout the year，with the highest proportion in May（18.42%）.（2）Out of 1 718 children with HRV infection，863 cases were hospitalized for pneumonia（50.23%，863/1 718）.The median age of hospitalized children was 2.58（1.07，4.20）years old，with 53.77% under 3 years old.（3）The main clinical manifestations of HRV pneumonia were cough（97.68%，843/863），fever（58.05%，501/863），runny nose（57.01%，492/863），nasal congestion（36.96%，319/863），and wheezing（24.33%，210/843）. The HRV pneumonia co-infection group showed statistically significant differences in fever and hospitalization days compared to the single HRV pneumonia infection group（all P<0.05）.（4）Compared to the common pneumonia group，the severe HRV pneumonia group showed statistically significant differences in fever，runny nose，wheezing and hospitalization days the CRP, PCT, LDH levels, and the number of antibiotic applications after hospitalization（all P<0.05）. Conclusion:HRV infection is detected year-round in Xiamen，pneumonia is common，with children under 3 years old being particularly susceptible.It is important to be alert to mixed infections or severe pneumonia.Clinical treatment should avoid unnecessary antibiotic use，actively and provide appropriate treatment.

Pancreatic cancer is highly aggressive and often diagnosed at an advanced stage,leaving most patients ineligible for radical resection.This study retrospectively analyzed four patients with locally advanced or advanced pancreatic cancer to evaluate the clinical efficacy and safety of high-intensity focused ultrasound(HIFU)ablation combined with chemotherapy as a neoadjuvant and conversion therapy.All cases were reviewed and individualized treatment plans were formulated through a multidisciplinary team evaluation.All patients received HIFU plus gemcitabine and nab-paclitaxel chemotherapy,with assessments of tumor volume,vascular involvement,surgical conversion,symptom relief,and adverse events.Three patients achieved marked tumor shrinkage and reduction of vascular invasion,enabling successful R0 resection without recurrence during follow-up.The remaining patient achieved disease stability,significant pain relief,and maintained good quality of life under repeated HIFU therapy.All treatments were well tolerated,and no severe adverse reactions occurred.The combination of HIFU and chemotherapy demonstrated synergistic local and systemic effects,effectively achieving tumor downstaging,improving resectability,and alleviating symptoms.As a safe,noninvasive,and repeatable therapeutic approach,this strategy offers a promising option for patients with advanced pancreatic cancer.Further large-scale prospective studies are warranted to validate its long-term efficacy and elucidate underlying mechanisms.

Background and Aims:Acute pancreatitis(AP)is an acute inflammatory disease of the pancreas caused by abnormal activation of pancreatic enzymes.Although gallstones,hyperlipidemia,and alcohol use are the most common causes,a subset of patients develop AP secondary to rare etiologies that are often misdiagnosed or diagnosed late,leading to recurrence or inappropriate management.This study aims to summarize the clinical characteristics,diagnostic strategies,and treatment outcomes of four cases of AP caused by uncommon etiologies,supported by a literature review.Methods:Clinical data of 4 patients admitted to the Department of Hepatobiliary and Pancreatic Surgery,the Third Xiangya Hospital of Central South University,between November 2021 and September 2024,were retrospectively analyzed.Their etiological characteristics,diagnostic approaches,and treatment strategies were reviewed in combination with relevant literature.Results:The underlying causes of AP were intraductal papillary mucinous neoplasm,pancreatic neuroendocrine tumor,pancreatic ductal adenocarcinoma,and duodenojejunal intussusception.All cases initially presented as idiopathic AP.Three patients underwent definitive surgical treatment and recovered well,while one patient with pancreatic cancer received only palliative care due to delayed diagnosis and died three months later.Conclusion:AP secondary to rare etiologies often mimics common forms in clinical presentation but poses diagnostic challenges.For patients with recurrent or idiopathic AP,clinicians should emphasize etiological tracing and utilize advanced imaging and endoscopic modalities for early identification.Timely etiological intervention,particularly surgical management when appropriate,is essential for preventing recurrence and improving prognosis.

Background and Aims:Infected necrotizing pancreatitis(INP),particularly with diffuse distribution,is a life-threatening condition.The optimal initial intervention-minimally invasive step-up therapy vs.direct open necrosectomy-remains controversial.Moreover,the impact of necrosis morphology("wet"or"dry")and the presence of severe acute pancreatitis(SAP)on treatment selection has not been fully clarified.This study aimed to compare the efficacy and safety of these two approaches in diffuse INP and to evaluate the guiding value of CT-based necrosis type and SAP status in clinical decision-making.Methods:A retrospective analysis was conducted on 458 patients with diffuse INP admitted to the Third Xiangya Hospital of Central South University from January 2012 to March 2023.Patients were divided into a minimally invasive step-up group(n=256)and a direct open surgery group(n=202).SAP was defined according to the determinant-based classification,and necrosis was categorized as"wet"or"dry"based on CT features.The primary endpoint was a composite of death or major complications,while secondary endpoints included mortality,length of hospital stay,and incision-related complications,were compared between the two groups,with subgroup analyses performed accordingly.Results:Overall,the open surgery group had higher rates of the primary endpoint(62.4%vs.48.1%,P=0.003)and mortality(27.2%vs.16.8%,P=0.008)compared with the step-up group.Among SAP patients,the step-up approach resulted in a significantly lower primary endpoint rate(66.7%vs.97.7%,P=0.003).In non-SAP patients,the primary endpoint rates were similar,but open surgery was associated with a shorter hospital stay[(36.5±10.4)d vs.(45.6±18.6)d,P<0.001]and higher incidences of wound infection and incisional hernia(both P<0.001).Multivariate analysis identified infection onset time,effusion characteristics,gas bubbles,and necrosis location as independent predictors of prolonged hospitalization in the step-up group(all P<0.05).Patients with"wet"necrosis benefited more from the step-up approach,whereas those with"dry"necrosis experienced shorter hospitalization following open surgery.Conclusion:For diffusely distributed INP,treatment strategies should be individualized based on SAP status and necrosis liquefaction/imaging characteristics.The step-up minimally invasive approach is preferred for SAP patients and those with"wet"necrosis on CT,while direct open necrosectomy may be advantageous for"dry"necrosis(particularly with limited liquefaction)by shortening hospital stay and reducing certain major outcomes,though at the cost of increased incision infection and incision herina.CT imaging features and SAP classification can serve as valuable tools for risk stratification and guiding individualized timing and modality of intervention.

Objective:To investigate the radioactivity levels and variation trends of 90Sr in drinking water and food around the Qinshan Nuclear Power Plant in operation. Methods:From 2012 to 2022, the source, factory, and tap water was collected within 30 km around the Qinshan Nuclear Power Plant during the wet and dry seasons (i.e., May and October, respectively) each year to determine the 90Sr concentration in water. According to the dietary habits of local residents, four kinds of food, including rice, cabbage, mullet, and crucian carp, were collected to determine and analyze the 90Sr radioactivity concentration in food using the bis-(2-ethylhexyl) phosphoric acid extraction chromatographic method. Results:From 2012 to 2022, the 90Sr radioactivity concentrations in the source, factory, and tap water around the Qinshan Nuclear Power Plant ranged from 3.73 to 11.89 mBq/L, 2.95 to 9.83 mBq/L, and 3.12 to 8.70 mBq/L, respectively, showing nonsignificant fluctuations over the years. The 90Sr radioactivity concentrations in rice, cabbage, mullet, and crucian carp ranged from 0.02 to 0.46 Bq/kg (dry weight), 0.26 to 1.07 Bq/kg (fresh weight), 0.38 to 1.05 Bq/kg (fresh weight), and 0.08 to 1.32 Bq/kg (fresh weight), respectively, all below the national standard limits. Conclusions:From 2012 to 2022, the 90Sr radioactivity levels in drinking water and food around the Qinshan Nuclear Power Plant were at the background level and remained stable.

Objective:To investigate the current situation of nuclear medicine practices, determine the number of nuclear medicine staff, conduct internal exposure monitoring and dose estimation for nuclear mecidine staff engaged in 131I treatment in Zhejiang province. Methods:A survey was conducted over all the 22 hospitals involved in 131I treatment in the province. The 131I activity in thyroid of 96 stafff in 131I treatment workplaces were measured by means of direct method. At the same time, the effective doses from internal exposure were estimated and the influencing factors were analyzed. Results:131I activity in thyroids was found to be above the detection limit for 49 staff (51.04%) in nineteen hospitals. The maximum value of 131I activity was 629.18 Bq. There was no statistically significant difference in 131I detection rate in thyroid of 131I treatment staff between different positions, different genders and different levels of hospitals ( P>0.05). Comparisons of 131I activity of thyroid of nuclear medicine staff for theatment of thyroid cancers had shown that the highest was for nurses, followed by technicians and doctors, and the lowest was for cleaning staff ( H=6.39, P<0.05). The estimated committed effective dose to the nuclear medicine staff ranged from 0.05 to 2.37 mSv, with those below 1 mSv accounting for 93.88% of the total. Logistic regression analysis showed that nursing position was the risk factor contributing to the committed effective dose ( OR=2.805, 95% CI 1.076-7.314). Conclusions:In Zhejiang province, the committed effective dose to thyroid of nuclear medicine staff from 131I internal exposure was not in excess of the dose limit. However, the staff performing iodine therapy still need to strengthen protection against internal exposure and take scientific and effective protective measures to reduce the risk of health hazards from internal exposure.