At present,precise radiotherapy has been widely used through the development with many years,but the existing technique still is limited by the limitation of tolerance dose of normal tissues,which cannot achieve the optimal goal of treating tumor.Flash radiotherapy(Flash-RT)is one kind of radiotherapy technique that uses the beam with ultra-high dose rate(UHDR)to conduct irradiation,which can furthest treat tumors while significantly reduce radiation injury of normal tissues.But until now,the biological mechanism,key physical parameters and triggering mechanism of Flash-RT are still unclear,and its principle and clinical translational application are still in the stage of research.This review clarified the technological advance and clinical translational application of Flash-RT research through summarized the relevant research of Flash-RT.

The increasing incidence of myopia has become a significant public health issue worldwide.Since its estab-lishment in 2015,the International Myopia Institute(IMI)has published a series of white papers on myopia prevention and control in 2019 and 2021,advancing the scientific management and clinical research of myopia prevention and control worldwide.In 2023,IMI released new white papers on myopia prevention and control.In this paper,the highlights of the third series of IMI white papers on children,young adults,and emerging research areas in myopia are interpreted,intend-ing to help related professionals understand the management and research focus of myopia patients of different ages.

The foveal avascular zone(FAZ)is the most sensitive region of the retina, which is interconnected by the macular capillary plexus. Its morphology can indirectly reflect the alterations of macular microcirculation. With strong repeatability and reliability, optical coherence tomography angiography(OCTA)can non-invasively visualize and quantify the FAZ. The great value of OCTA makes it an important supplemental examination tool in ophthalmology and other professions. The area and perimeter of FAZ have been demonstrated to be an effective clinical diagnostic indicator in high myopia, diabetic retinopathy, glaucoma and other ocular diseases. In recent years, the geometry of FAZ has also proven to have clinical value. The parameters describing the geometry of FAZ, such as circularity index, acircularity index and axial ratio, provide a new perspective for ocular disease research. The comprehensive investigation of the morphological characteristics of the FAZ is helpful to explore the pathological mechanism of the occurrence and development of ocular diseases, predict preclinical changes, make pathological stages of the disease precise, and provide a theoretical basis for monitoring the disease's progression and assessing patients' visual prognosis.

Myopia shows a trend of high incidence and low age,and the number of high myopia patients is increasing year by year.Safe and effective myopia intervention measures are the top priority of myopia prevention and control.It has been found that low-dose atropine,orthokeratology,repeated low-level red light and other treatment methods have reliable efficacy,which can provide a variety of options for myopia prevention and control in children.The choroid,as an impor-tant anatomical structure of the fundus,is closely related to the mechanism of myopia.Choroidal parameters may become markers for evaluating the effect of myopia prevention and control and monitoring the progression of myopia.With the con-tinuous development of medical imaging technology,choroidal thickness and microcirculatory parameters have been accu-rately quantified.Further exploration of the changes of choroid under various myopia intervention measures will help clini-cians design personalized treatment plans for different patients,which is of great clinical significance for the management of myopia prevention and control.In this article,the research progress on choroidal thickness and blood flow changes under different myopia prevention and control measures are reviewed.

l-Heptopyranoses are important components of bacterial polysaccharides and biological active secondary metabolites like septacidin (SEP), which represents a group of nucleoside antibiotics with antitumor, antifungal, and pain-relief activities. However, little is known about the formation mechanisms of those l-heptose moieties. In this study, we deciphered the biosynthetic pathway of the l,l-gluco-heptosamine moiety in SEPs by functional characterizing four genes and proposed that SepI initiates the process by oxidizing the 4'-hydroxyl of l-glycero-α-d-manno-heptose moiety of SEP-328 ( 2) to a keto group. Subsequently, SepJ (C5 epimerase) and SepA (C3 epimerase) shape the 4'-keto-l-heptopyranose moiety by sequential epimerization reactions. At the last step, an aminotransferase SepG installs the 4'-amino group of the l,l-gluco-heptosamine moiety to generate SEP-327 ( 3). An interesting phenomenon is that the SEP intermediates with 4'-keto-l-heptopyranose moieties exist as special bicyclic sugars with hemiacetal-hemiketal structures. Notably, l-pyranose is usually converted from d-pyranose by bifunctional C3/C5 epimerase. SepA is an unprecedented monofunctional l-pyranose C3 epimerase. Further in silico and experimental studies revealed that it represents an overlooked metal dependent-sugar epimerase family bearing vicinal oxygen chelate (VOC) architecture.

Objective　The predisposing factors,clinical characteristics and imaging characteristics of intracranial and extracranial vertebral artery dissection are compared to understand the influence on the location of vertebral artery dissection and the ultrasonic characteristics of different parts.Methods　Forty-four patients with vertebral artery dissection diagnosed in the Department of Neurology of our hospital from June 2017 to June 2021 were selected and divided into intracranial group and extracranial group according to different lesion sites of vertebral artery dissection.The differences in baseline data,susceptibility factors,clinical manifestations and ultrasonic characteristics of the two groups were compared.Results　A total of forty-four patients were enrolled and were divided into intracranial vertebral artery dissection group (n=20 cases) and extracranial artery dissection group (n=24 cases).The incidence of massage or trauma in extracranial was significantly higher than that in intracranial (P=0.01).Headache symptoms were more common in intracranial group (P=0.04),however there were no significant differences in clinical features such as dizziness,hemiplegia,dysphagia and Horner’s sign between the two groups (P>0.05).Intramural hematoma was the most common ultrasonic characteristics in patients with vertebral artery dissection,and Ultrasonography was significantly limited in the intracranial segment.It is simple to operate,non-invasive,inexpensive and easy to popularize.Conclusions　The predisposing factors and clinical manifestations of vertebral artery dissection are not identical in different parts.

Objective　To evaluate the diagnostic value of superb microvascular imaging(SMI) in cervical artery dissection.Methods　A total of 42 patients with cervical artery dissection diagnosed by the Department of Neurology of our hospital from June 2017 to June 2021 were collected to evaluate the consistency of SMI and CTA/MRA+DSA in the diagnosis of cervical artery dissection,and to compare the accuracy and sensitivity of SMI.Results　Among 42 patients,the positive rate of cervical artery dissection with ultrasonography,SMI,CTA or MRA and DSA were 42.8 %（18/42）,90.4% （38/42） and 92.6%（39/42） respectively.The DSA mostly showed the line-like sign(n=19,48.7%); Ultrasonography and SMI mostly showed the intramural hematoma.SMI and CTA/MRA+DSA showed the good consistency in the diagnosis of cervical artery dissection（Kappa=0.340，P=0.056).Superb microvascular imaging was superior to ultrasonography in the detection of cervical artery dissection（Kappa=5.895，P=0.015）.The area under the ROC superb microvascular imaging diagnosis of cervical artery dissection was 0.966.It is suggested that superb microvascular imaging has high accuracy in diagnose cervical artery dissection.Conclusion　Superb microvascular imaging has high clinical value in the diagnosis of various types of cervical artery dissection.

It has been reported that ODB genes play an important role in homologous recombination-directed DNA repair, suggesting their potential applications in plant breeding. To analyze the expression characteristics of tobacco NtODB gene, the cDNA sequence of NtODB was obtained using in silico cloning technique. The physicochemical properties, signal peptide, and advanced structures of the predicted protein were analyzed using bioinformatics tools. The results showed that the NtODB gene has a 579-bp open reading frame which encodes a protein with 192 amino acid residues. The protein NtODB is predicted to be alkaline and hydrophilic. Real-time quantitative PCR showed that NtODB was constitutively expressed in different tissues. Subcellular localization showed that NtODB was mainly expressed in cell membrane and chloroplast. These results may help us to better understand and elucidate the roles of ODB genes in the homologous recombination-directed DNA repair.
Amino Acid Sequence ; Base Sequence ; Cloning, Molecular ; Computational Biology ; Computer Simulation ; DNA, Complementary ; Phylogeny ; Plant Breeding ; Tobacco/genetics*

Objective:To resolve the issue of poor automatic segmentation of the bowel in women with pelvic tumors, a Dense V-Network model was established, trained and evaluated to accurately and automatically delineate the bowel of female patients with pelvic tumors.Methods:Dense Net and V-Net network models were combined to develop a Dense V-Network algorithm for automatic segmentation of 3D CT images. CT data were collected from 160 patients with cervical cancer, 130 of which were randomly selected as the training set to adjust the model parameters, and the remaining 30 were used as test set to evaluate the effect of automatic segmentation.Results:Eight parameters including Dice similarity coefficient (DSC) were utilized to quantitatively evaluate the segmentation effect. The DSC value, JD, ΔV, SI, IncI, HD (cm), MDA (mm), and DC (mm) of the small intestine were 0.86±0.03, 0.25±0.04, 0.10±0.07, 0.88±0.05, 0.85±0.05, 2.98±0.61, 2.40±0.45 and 4.13±1.74, which were better than those of any other single algorithm.Conclusion:Dense V-Network algorithm proposed in this paper can deliver accurate segmentation of the bowel organs. It can be applied in clinical practice after slight revision by physicians.

Background and aims:To investigate the safety and efficacy of direct-acting antiviral(DAA)regimens in a cohort of Chinese patients with chronic hepatitis C virus(HCV)infection. Methods:A total of 222 adult Chinese patients were enrolled and treated via DAA regimens in accor-dance with HCV management guidelines.Treatment responses were evaluated 4 weeks after treatment,at the end of treatment(EOT)and 12 weeks post-treatment.Virological responses,biochemical re-sponses,model for end-stage liver disease(MELD)and Child-Pugh(CP)scores were recorded. Results:A total of 218 patients(98.2％)achieved sustained virological response 12 weeks post-treatment and 4 patients relapsed.The combined number of rapid virological responses for all six regimens was 170/222(76.6％),and 221/222(99.6％)had achieved virological responses by the end of treatment.In decompensated cirrhosis patients the baseline mean CP score was 6.8±1.3 and the mean MELD score was 10.1±3.3.Compared with the mean CP score at baseline,the mean score is significantly lower at the end of treatment(5.7±1.3)and 12 weeks post-treatment(5.6±1.0).Estimated glomerular filtration rates did not differ significantly from baseline during the treatment or 12 weeks post-treatment.The incidence of adverse events in patients with chronic hepatitis C and compensated cirrhosis was 42/172(24.4％),and in patients with decompensated cirrhosis it was 8/22(36.4％).The most frequently reported adverse events were elevated indirect bilirubin,fatigue and rash.There were no cases of serious adverse events,death or treatment discontinuation because of adverse events. Conclusion:DAA regimens were highly effective and well tolerated irrespective of HCV genotype,cirrhosis,liver or kidney transplantation,hepatocellular carcinoma,HCV/hepatitis B virus co-infection,or renal failure.