Objective To investigate the current distribution and predict the future suitable habitats of Haemaphysalis longicornis in Nanjing City, so as to provide insights into control and early warning of ticks and management of tick-borne diseases in Nanjing City. Methods The electronic map of Nanjing City was obtained from the National Platform for Common GeoSpatial Information Services. The distribution of H. longicornis and the longitude and latitude of distribution points from 2022 to 2024 were obtained from centers for disease control and prevention across each district in Nanjing City. Climatic and environmental variable data in Nanjing City were captured from the Worldclim database. Initially, 19 bioclimatic variables in this database were selected, including annual mean temperature, mean diurnal range, isothermality, temperature seasonality, maximum temperature of the warmest month, minimum temperature of the warmest month, temperature annual range, mean temperature of the wettest quarter, mean temperature of the driest quarter, mean temperature of the warmest quarter, mean temperature of the coldest quarter, annual precipitation, precipitation of the wettest month, precipitation of the driest month, precipitation seasonality, precipitation of the wettest quarter, precipitation of the driest quarter, precipitation of the warmest quarter, and precipitation of the coldest quarter. The elevation and normalized difference vegetation index were obtained from Data Sharing Platform of the Center for Resources and Environmental Sciences, Chinese Academy of Sciences. Then, the distribution points of H. longicornis, elevation, vegetation index and 19 bioclimatic variables were loaded into the software MaxEnt 3.4.4 to evaluate and screen out the variables with a contribution rate of 1% and higher. ArcGIS 10.8.1 software was used to extract the elevation, vegetation index and 19 bioclimatic variables of the distribution points of H. longicornis for a correlation analysis. If the absolute value of the correlation coefficient was 0.8 and higher, the variable with the higher contribution was retained. The 2050 dataset of the BCCCSM2-MR atmospheric circulation model in the coupled model intercomparison project phase 6 (CMIP6) were obtained from the Worldclim database as climate data for 2050. Screened H. longicornis species data and environmental and climate data were loaded into the maximum entropy (MaxEnt) model with the software MaxEnt 3.4.4 for training and validation, and then, all data generated from the model were imported into the software ArcGIS 10.8.1 to generate raster data and yield the map pertaining to the distribution of H. longicornis risk in Nanjing City. The accuracy of the model was evaluated with a receiver operating characteristic (ROC) curve, and the predictive effect of the model was assessed with area under the ROC curve (AUC). The suitable habitats of H. longicornis were classified in Nanjing City with the software ArcGIS 10.8.1, and the areas of distribution of suitable habitats in various categories were recorded to create the map of current H. longicornis suitable habitats classification in Nanjing City. The climatic and geographic information data in 2050 were employed as future environmental and climatic factors, and current environmental and climatic factors and current H. longicornis distribution data were additionally used to predict the future suitable habitats of H. longicornis in Nanjing City. In addition, the contributions of environmental and climatic factors to distribution of suitable habitats of H. longicornis was evaluated with the Jackknife method in Nanjing City. Results A total of 10 environmental and climatic variables were screened for analysis of the suitability of H. longicornis in Nanjing City based on correlation analyses and contributions of the MaxEnt model, including annual mean temperature, precipitation of the warmest quarter, vegetation index, precipitation of the wettest month, temperature annual range, annual precipitation, mean temperature of the warmest quarter, elevation, mean temperature of the wettest quarter, and maximum temperature of the warmest month, and annual mean temperature (34.8%), precipitation of the warmest quarter (17.3%), vegetation index (13.1%), and precipitation of the wettest month (10.8%) contributed relatively highly to the distribution of suitable habitats of H. longicornis in Nanjing City. The mean AUC of the ROC curve was 0.810 ± 0.055 for 10 repeated modeling results of the MaxEnt model, indicating high predictive performance of the model. The potential distribution areas of H. longicornis were predicted to be mainly located in Luhe District, Pukou District, Jiangning District, Lishui District, and Gaochun District in Nanjing City with the MaxEnt model. Under current climatic conditions, the area of potential suitable habitats of H. longicornis was 4 182.42 km² in Nanjing City, including 1 252.94 km² highly suitable habitats, which accounted for 19.00% of the total area of Nanjing City. Under the climate scenario in 2050, the area of potential suitable habitats of H. longicornis was projected to increase to 5 467.58 km² in Nanjing City, accounting for 82.95% of the total area of the city, and these habitats were mainly concentrated in Luhe District, Pukou District, Jiangning District, Lishui District, and Gaochun District. The areas of suitable habitats of H. longicornis at various categories were predicted to vary greatly in 2050, and the area of highly suitable habitats of H. longicornis was projected to increase to 2 378.82 km², accounting for 36.08% of the total area of Nanjing City. Based on jackknife tests and contributions of environmental and climatic variables, 6 dominant environmental and climatic factors were screened, including annual mean temperature (34.8% contribution), precipitation of the warmest quarter (17.3% contribution), vegetation index (13.1% contribution), precipitation of the wettest month (10.8% contribution), temperature annual range (5.4% contribution), and mean temperature of the warmest quarter (5.0% contribution), with cumulative contributions of 86.4%. Conclusion The distribution of H. longicornis is strongly associated with vegetation, temperature and precipitation in Nanjing City. Future climate change may lead to an expansion of the distribution area of H. longicornis in Nanjing City.

Objective:To evaluate the clinical value of sacral canal posterior wall reconstruction in the treatment of symptomatic sacral canal cysts.Methods:A retrospective cohort study was conducted.The clinical data of 80 patients with symptomatic sacral cysts who underwent surgical treatment at Beijing Friendship Hospital, Capital Medical University, between June 2018 and September 2024 were collected. There were 19 males and 61 females, with an average age of (49.0±11.3) years (ranged from 23-76 years). The patients were divided into the traditional group ( n=30) and the reconstruction group ( n=50) based on the surgical approach. The traditional group underwent the conventional surgical method without reconstruction of the posterior wall of the sacral canal, while the reconstruction group underwent posterior wall reconstruction of the sacral canal. Postoperative observations included the integrity of the sacral canal posterior wall, wound healing, and symptom improvement in both groups. Measurement data with normal distribution were expressed as mean±standard deviation( ± s). Independent samples t-test was used for comparisons of measurement data between groups. Categorical data were compared using the chi-square test or Fisher′s exact test. Ordinal data were analyzed using the Mann-Whitney U test. Pearson correlation analysis was used to assess the relationship between variables. Results:Among the 80 patients, the sacral bone integrity score in the reconstruction group was (1.42±0.49) scores, compared to (3.00±0.00) scores in the traditional group, the reconstruction group showed significantly better results ( P<0.05). Symptom improvement was also significantly different between the two groups ( P=0.038): in the traditional group, 17 patients experienced complete symptom resolution, 6 partial improvement, 7 no improvement, and 0 worsening; in the reconstruction group, 37 had complete symptom resolution, 11 partial improvement, 2 no improvement, and 0 worsening. The effective improvement rate (complete+ partial improvement) in the reconstruction group was significantly better than that in the traditional group ( P=0.012). In terms of wound healing, 76 cases healed well, 4 had delayed healing, and 0 had infections. In the traditional group, 27 healed well, 3 had delayed healing, 0 infections; in the reconstruction group, 49 healed well, 1 had delayed healing, and 0 infections. There was no significant difference in wound healing rate between the two groups ( P=0.146). A significant positive correlation was found between sacral canal posterior wall integrity and symptom improvement ( r=0.288, P=0.010). Conclusion:Sacral canal posterior wall reconstruction significantly improves postoperative anatomical integrity and clinical outcomes without increasing complications, supporting its adoption as a preferred surgical approach for symptomatic sacral canal cysts.

Extensive epigenetic reprogramming involves in memory CD8+ T-cell differentiation. The elaborate epigenetic rewiring underlying the heterogeneous functional states of CD8+ T cells remains hidden. Here, we profile single-cell chromatin accessibility and map enhancer-promoter interactomes to characterize the differentiation trajectory of memory CD8+ T cells. We reveal that under distinct epigenetic regulations, the early activated CD8+ T cells divergently originated for short-lived effector and memory precursor effector cells. We also uncover a defined epigenetic rewiring leading to the conversion from effector memory to central memory cells during memory formation. Additionally, we illustrate chromatin regulatory mechanisms underlying long-lasting versus transient transcription regulation during memory differentiation. Finally, we confirm the essential roles of Sox4 and Nrf2 in developing memory precursor effector and effector memory cells, respectively, and validate cell state-specific enhancers in regulating Il7r using CRISPR-Cas9. Our data pave the way for understanding the mechanism underlying epigenetic memory formation in CD8+ T-cell differentiation.
CD8-Positive T-Lymphocytes/metabolism* ; Cell Differentiation ; Chromatin/immunology* ; Animals ; Mice ; Immunologic Memory ; Epigenesis, Genetic ; SOXC Transcription Factors/immunology* ; NF-E2-Related Factor 2/immunology* ; Mice, Inbred C57BL ; Gene Regulatory Networks ; Enhancer Elements, Genetic

OBJECTIVE: To precise classify sacral meningeal cysts, effective guide minimally invasive neurosurgery and postoperative personalized rehabilitation by multiple dimensions radiographic reconstruction MRI. METHODS: From March to December 2021, based on the original 3D-fast imaging employing steadystate acquisition (FIESTA) scanning sequence, 92 patients with sacral meningeal cysts were pre-operatively evaluated by multiple dimensional reconstruction MRI. The shape of nerve root and the leakage of cyst were reconstructed according to the direction of nerve root or leakage track showed on original MRI scans. Sacral canal cysts were accurately classified as including nerve root and without nerve root, so as to accurately design the incision of skin and formulate corresponding open range of the posterior wall of the sacral canal. Under the microscope intraoperation, the shape of the nerve roots inside cysts or leakage track of the cysts without nerve roots were verified and explored. After the reinforcement and shaping operation, several reexaminations of multiple dimensional reconstruction MRI were performed to understand the deformation of the nerve root and hydrops in the operation cavity, so as to formulate a persona-lized rehabilitation plan for the patients. RESULTS: Among the 92 patients with sacral mengingeal cyst, 58 (63.0%) cysts with nerve root cyst, 29 (31.5%) cysts without nerve root cyst, and 5 (5.4%) cysts with mixed sacral canal cyst. In 58 patients with nerve root cysts, the accuracy of preoperative clinical classification on MRI image reached 96.6% (56/58) through confirmation by operating microscope. Only 2 cases of large single cyst with nerve root on the head of cyst were mistaken for without nerve root type. In 29 patients with sacral cyst without nerve root, the accuracy of preoperative image reached 100% through confirmation by operating microscope. The accuracy of judging the internal nerve root and leakage of 12 cases with recurrent sacral cyst was also 100%. Two cases of delayed postoperative hydrops were found one month after operation. After rehabilitation treatment by moxibustion and bathing, the hydrops disappeared 4-6 months after operation. CONCLUSION Multiple dimensional reconstruction MRI can precisely make clinical classification of sacral meningeal cysts before operation, guide minimally invasive neurosurgery effectively, and improve the rehabilitation effect.
Humans ; Magnetic Resonance Imaging/methods* ; Male ; Female ; Sacrum/surgery* ; Adult ; Middle Aged ; Imaging, Three-Dimensional/methods* ; Cysts/rehabilitation* ; Aged ; Adolescent ; Young Adult ; Spinal Nerve Roots/diagnostic imaging* ; Minimally Invasive Surgical Procedures ; Neurosurgical Procedures/methods*

Allergen-specific immunotherapy（AIT） remains the only therapeutic approach with the potential to modify the natural course of allergic rhinitis（AR）. Nevertheless, considerable inter-individual variability exists in patients'responses to AIT. To facilitate more reliable assessment of treatment efficacy, the China Rhinopathy Research Cooperation Group（CRRCG） convened young and middle-aged nasal experts in China to formulate the present consensus. The recommended subjective outcome measures for AIT comprise symptom scores, medication scores, combined symptom and medication scores, quality-of-life assessments, evaluation of disease control, and assessment of comorbidities. Objective indicators may supplement these measures. Currently available objective approaches include skin prick testing, nasal provocation testing, and allergen exposure chambers. However, these methods remain constrained by practical limitations and are not yet appropriate for routine implementation in clinical efficacy evaluation. In addition, several biomarkers, including sIgE and the sIgE/tIgE ratio, sIgG4, serum IgE-blocking activity, IgA, cytokines and chemokines, as well as immune cell surface molecules and their functional activity, have been shown to have associations with AIT outcomes. While these biomarkers may complement subjective assessments, they are subject to significant limitations. Consequently, large-scale multicenter trials and real-world evidence are required to strengthen the evidence base. The present consensus underscores the necessity of integrating patients'subjective experiences with objective testing throughout the treatment process, thereby providing a more comprehensive and accurate framework for efficacy evaluation. Looking forward, future investigations should prioritize the incorporation of multi-omics data and artificial intelligence methodologies, which hold promise for overcoming current limitations in assessment strategies and for advancing both the standardization and personalization of AIT.
Humans ; Allergens/immunology* ; China ; Consensus ; Desensitization, Immunologic ; Immunoglobulin E ; Quality of Life ; Rhinitis, Allergic/therapy* ; Treatment Outcome ; East Asian People

Objective To construct YOLOv10 based artificial intelligence(AI)models for the automatic detection in small bowel capsule endoscopy(SBCE)images.Methods SBCE data from two centers was collected,including 23 115 images and 35 412 annotated labels covering 11 categories of small bowel lesions.The images were annotated using the LabelMe tool and converted into the YOLO format required for deep learning model development.The pre-trained YOLOv10 and YOLOv8 models were used for transfer learning training on the constructed dataset.Model performance was comprehensively evaluated using metrics such as precision,accuracy,sensitivity,specificity,false-positive rate,and detection speed.Finally,the models were deployed on local computers for real-time detection of SBCE images and videos.Results Six different versions of YOLO object detection models were developed,namely YOLOv8n,YOLOv8s,YOLOv8m,YOLOv10n,YOLOv10s,and YOLOv10m.On the validation set,YOLOv10s model achieved the best mAP50(0.795);although its inference latency was not the fastest(4.803 ms/img),it met the requirements for clinical application.On the test set,YOLOv10s performed well,with an accuracy of 92.69%,a sensitivity of 89.23%,and a false-positive rate of 4.78%.Especially,in category-specific inference,the highest sensitivity was for"bleeding"at 96.41%,while the lowest was for"narrowing"at 82.29%.Conclusion The model constructed based on YOLOv10 neural network can rapidly and accurately detect and classify various small bowel lesions,exhibiting significant clinical application potential.

Objective:To investigate the relationship between blood pressure trajectories and blood pressure variability with the risk of target organ damage in Chinese population from childhood to middle age.Methods:This study is a population-based, long-term follow-up cohort study. Participants who had their blood pressure measured at least 5 times in the Hanzhong Adolescent hypertension cohort from 1987 to 2023 were included in this study. Group-based trajectory modeling was used to identify different systolic and diastolic blood pressure trajectories, and the subjects were divided into low-increasing group, moderate-increasing group and high-increasing group according to blood pressure trajectories. Blood pressure variability was assessed using standard deviation (SD), variability independent of the mean (VIM), and average real variability (ARV). Target organ damage was evaluated during the final follow-up in 2023 (middle age). Logistic regression models were used to analyze the relationship between blood pressure trajectories and blood pressure variability with the risk of target organ damage.Results:A total of 2 447 subjects were included, with a median age of 48 years, of whom 1 373 were male (56.1%). Based on systolic blood pressure, 868 were in the low-increasing group, 1 238 in the moderate-increasing group, and 341 in the high-increasing group. For diastolic blood pressure, the distribution was 894, 1 263 and 290, respectively. Compared with the low-increasing group of systolic blood pressure, the moderate-increasing group (arteriosclerosis: OR=4.14, 95% CI 2.96-5.79; proteinuria: OR=2.06, 95% CI 1.38-3.07; left ventricular hypertrophy: OR=1.68, 95% CI 1.00-2.82) and high-increasing group (arterial stiffness: OR=15.44, 95% CI 10.14-23.50; proteinuria: OR=5.80, 95% CI 3.63-9.29; left ventricular hypertrophy: OR=2.93, 95% CI 1.55-5.53) had a higher risk of target organ damage (all P<0.005). The moderate-increasing group of diastolic blood pressure had a higher incidence of arterial stiffness ( OR=3.72, 95% CI 2.69-5.12) and proteinuria ( OR=1.67, 95% CI 1.15-2.42) than the low-increasing group (all P<0.005), while the high-increasing group had a significantly higher risk of all type of target organ damage compared to the low-increasing group (arterial stiffness: OR=10.84, 95% CI 7.08-16.61; proteinuria: OR=3.72, 95% CI 2.31-5.99; left ventricular hypertrophy: OR=2.38, 95% CI 1.23-4.59; all P<0.005). Additionally, higher systolic blood pressure variability was associated with an increased incidence of arterial stiffness (SD: OR=2.25, 95% CI 1.96-2.57; VIM: OR=1.64, 95% CI 1.45-1.86; ARV: OR=1.70, 95% CI 1.50-1.93) and proteinuria (SD: OR=1.65, 95% CI 1.44-1.89; VIM: OR=1.41, 95% CI 1.22-1.63; ARV: OR=1.45, 95% CI 1.26-1.67; all P<0.005). The results for diastolic blood pressure variability indicators were similar to those for systolic blood pressure. Conclusion:Early-life blood pressure trajectories are predictive of target organ damage risk in middle age. Higher blood pressure variability is related to an increased risk of arterial stiffness and proteinuria, but was less associated with left ventricular hypertrophy. Focusing on the risk of high blood pressure early in life can help prevent the occurrence of target organ damage in middle age.

Objective:To explore the impact of the two-way referral model on compliance and prognosis in patients with heart failure.Methods:This bidirectional cohort study enrolled chronic heart failure (CHF) patients treated at Qilu Hospital of Shandong University or designated primary hospitals between March 2018 and March 2022. Patients were categorized into two groups based on referral status: two-way referral group (participating in the referral model with≥1 follow-up visit at primary hospitals) and the core hospital group (receiving treatment and follow-up exclusively at Qilu Hospital). Baseline clinical characteristics were collected and compared between groups. Patients underwent followed-up, with primary endpoints including follow-up rate, drug (β-blockers, angiotension converting enzyme inhibitor (ACEI)/angiotensin Ⅱ receptor blockers (ARB)/angiotensin receptor-neprilysin inhibitor (ARNI), sodium-glucose cotransporter 2 inhibitors and mineralocorticoid receptor antagonists) utilization rate and target dose achievement rate. Secondary endpoints encompassed changes from baseline in left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDd), and N-terminal pro-brain natriuretic peptide (NT-proBNP), plus cardiovascular mortality and heart failure rehospitalization. Generalized linear mixed models analyzed longitudinal trends in LVEF, LVEDd, and NT-proBNP levels. Kaplan-Meier curves and Cox regression evaluated LVEF recovery rates, supplemented by subgroup analyses. Multivariate logistic regression was used to identify factors influencing target dose achievement rate for β-blockers and ACEI/ARB/ARNI therapies in CHF patients.Results:A total of 357 patients were enrolled, aged 53 (41, 63) years, including 256 males (71.7%). 157 patients were in the two-way referral group and 200 patients in the core hospital-treated group. Compared with the core hospital-treated group, the two-way referral group had lower baseline LVEF (28 (22, 34)% vs. 31 (23, 36)%, P=0.021) and systolic blood pressure (116 (104, 125) mmHg vs. 121 (109, 134) mmHg (1 mmHg=0.133 kPa), P=0.010). The 12-month follow-up rate of the two-way referral group was higher than the core hospital-treated group (73.8% vs. 56.0%, P=0.004). No significant between-group differences were observed in drug utilization rate of β-blockers, ACEI/ARB/ARNI, or sodium-glucose cotransporter 2 inhibitors during follow-up (all P>0.05), while mineralocorticoid receptor antagonists use showed a declining trend in both groups. Although the core hospital-treated group had higher target dose achievement rates for β-blockers (65.4% vs. 49.3%, P=0.042) and ACEI/ARB/ARNI (79.8% vs. 65.8%, P=0.046) than the two-way referral group, multivariate logistic regression indicated that the two-way referral model was not a negative predictor for these outcomes (all P>0.05). Both groups showed improved NT-proBNP, LVEDd, and LVEF from baseline (all P<0.001) with no significant difference in trends between groups (all P>0.05). There was no significant difference in the composite incidence (7.6% vs. 6.5%, P=0.674) and cumulative incidence (log-rank P=0.684) of cardiovascular death and heart failure rehospitalization at 12 months between two groups. Conclusion:The two-way referral model demonstrates advantages in improving medication adherence, drug utilization rates, and targetdoseachievement rates among CHF patients. This model not only promotes cardiac functional recovery but also reduces risks of cardiovascular mortality and heart failure rehospitalization, achieving comparable therapeutic and management outcomes to those observed in core hospital-treated patients.

Objective To evaluate the efficacy and safety of polyethylene glycol electrolyte powder(PEG)combined with linaclotide(Lin)for bowel preparation in elderly constipated patients before colonoscopy.Methods In this prospective,randomized controlled trial,90 elderly patients with constipation undergoing colonoscopy were recruited at our hospital from June 2022 to December 2023.Participants were randomly assigned to three groups(n=30 each):PEG-3L alone,PEG-3L+Lin,and PEG-2L+Lin.Primary outcome was Boston Bowel Preparation Scale(BBPS)score and secondary outcomes included adverse event rates,colonoscopy completion rate,withdrawal time,and polyp detection rate.Statistical analysis was performed using independent t-tests and chi-square tests.Results The PEG-3L+Lin group achieved significantly higher BBPS scores than both PEG-3L alone and PEG-2L+Lin groups did(both P<0.001).The PEG-2L+Lin group also outperformed the PEG-3L alone group in cleansing efficacy(90.0%vs.76.7%,P=0.008).The PEG-2L+Lin group demonstrated the best tolerability and lowest adverse event rate,the PEG-3L group had the longest withdrawal time(P<0.05),but the three groups showed no significant difference in polyp detection rates.Conclusion PEG combined with linaclotide significantly improves bowel cleansing in elderly constipated patients.PEG-2L+Lin regimen provides optimal balance between efficacy,safety,and tolerability,making it a preferable choice for this population.

Objective To investigate the effects of aerobic exercise and different exercise habits on skeletal muscle function and the possible molecular mechanisms in colorectal cancer-loaded mice.Methods Thirty-five 5-week-old BABL/c male mice were acclimatized to feeding for 1 week and then divided randomly into the following groups:control(D),tumor(M),exercise preconditioning(QAM),lifetime exercise(AM),and exercise(HAM)groups(n=7 mice per group).Mice in the QAM and AM groups underwent aerobic exercise regimen 1 from weeks 2～6.At week 7,mice in the experimental groups received 0.2 mL of CT26 colon cancer cell suspension subcutaneously in the dorsal aspect of the left hind limb,while control mice received 0.2 mL of saline at the corresponding site.Mice in the AM and HAM groups were subjected to aerobic exercise regimen 2 for weeks 7～9.The general status and skeletal muscle mass and function were monitored in all mice throughout the experiments.After completion of the experiment,samples were collected and the cross-sectional area of gastrocnemius muscle fibers(CSA)was measured by hematoxylin and eosin staining and expression levels of proteins related to synthesis and catabolism of the gastrocnemius muscle were analyzed by Western Blot.Results(1)The weight ratio of the gastrocnemius muscle was significantly lower in mice in the M,QAM,and HAM groups compared with group D,and was significantly higher in AM mice compared with M,QAM,and HAM mice.(2)Grip strength,endurance,skeletal muscle circumference,and CSA were significantly lower in group D mice compared with the other groups,and was most enhanced in group HAM.Endurance and CSA were consistently enhanced in groups QAM,AM,and HAM.(3)Muscle RING-finger protein-1(MuRF1)expression levels were significantly lower in groups M,QAM,AM,and HAM than in group D,significantly lower in groups AM and HAM than in group M,and significantly lower in group HAM than in group QAM.(4)Fibronectin type Ⅲ domain-containing protein 5(FNDC5)expression levels were significantly lower in group M than in groups D and QAM.(5)Peroxisome proliferator-activated receptor gamma coactivator 1-alpha expression levels were significantly lower in the QAM and HAM groups compared with group M.(6)Expression levels of phospho(p)-AMP-activated protein kinase(AMPK)/AMPK and p-AMPK were significantly higher in group QAM than in groups D and M,p-AMPK expression significantly lower in groups AM and HAM was than in group QAM,and AMPK expression was significantly lower in groups QAM,AM,and HAM than in group D.Conclusions Exercise preconditioning and continuous aerobic exercise can improve skeletal muscle mass and function in CT26 colon cancer-loaded mice by activating AMPK phosphorylation to stimulate skeletal muscle secretion of FNDC5,thereby regulating the expression of MuRF1 protein.