Sludge dewaterability: The variation of extracellular polymeric substances during sludge conditioning with two natural organic conditioners.

To assess the characteristics of Extracellular Polymeric Substances during natural organic conditioners for sludge treatment, Moringa oleifera (MO) and chitosan (CTS) were used as conditioners. The findings of this study show that despite the high EPS content due to the fact that this component is not destroyed upon conditioning, sludge conditioned with MO and CTS displayed efficient and improved dewaterability. MO and CTS showed the same mechanism of action by protonation of the negatively charged EPS and reduction of electrostatic repulsions between sludge flocs, thus enhancing sludge filterability by neutralizing and settling. The effect of MO and CTS on EPS lies in their ability to neutralize EPS, settling them. MO and CTS neutralize and aggregate the EPS, hence improving sludge dewaterability. The results indicate that CTS can impact the EPS quantity and quality while MO impacts the EPS quality. Understanding the impact of MO and CTS on sludge EPS can help elucidate the mechanism of their dewaterability efficiency.

[Identification and target prediction of conserved microRNAs in Ammopiptanthus mongolicus].

Ammopiptanthus mongolicus, a woody plant growing in the desert, plays a vital role in vegetation maintaining and restoration in the arid region in northwest China. The plant exhibits an extremely high tolerance to abiotic stress such as drought and freezing stresses, and it has been used as an ideal model for abiotic stress tolerance research in trees. MicroRNA (miRNA) is a class of approximately 21nt endogenous non-protein-coding small RNA, which plays an important role in plant growth, development and responses to environmental stresses. By now, a large number of miRNAs have been reported in many plant species, but no studies describing A.mongolicus miRNA were published. In the present study, the types, expression levels, and putative target genes of conserved miRNAs in seedlings of A. mongolicus were analyzed using small RNA deep sequencing technology and bioinformatics methods. Nineteen conserved miRNAs, which belong to 10 miRNA families, were identified, with abundance ranging from 55 to 1920269 reads. Target prediction analysis determined the target genes of 14 conserved miRNAs. The functional classification analysis indicated that the conserved miRNAs participate in the development and environmental response by regulating the biological processes including the transcription regulation, hormone signal transduction, metabolisms and stress resistance.

Propagation equation of Hermite-Gauss beams through a complex optical system with apertures and its application to focal shift.

Based on the generalized Huygens-Fresnel diffraction integral (Collins' formula), the propagation equation of Hermite-Gauss beams through a complex optical system with a limiting aperture is derived. The elements of the optical system may be all those characterized by an ABCD ray-transfer matrix, as well as any kind of apertures represented by complex transmittance functions. To obtain the analytical expression, we expand the aperture transmittance function into a finite sum of complex Gaussian functions. Thus the limiting aperture is expressed as a superposition of a series of Gaussian-shaped limiting apertures. The advantage of this treatment is that we can treat almost all kinds of apertures in theory. As application, we define the width of the beam and the focal plane using an encircled-energy criterion and calculate the intensity distribution of Hermite-Gauss beams at the actual focus of an aperture lens.

Deep brain stimulation of the subthalamic nucleus improves sleep in Parkinson disease patients: A systematic review and meta-analysis.

BACKGROUND: Sleep disorders significantly affect the quality of life in Parkinson disease (PD) patients. Deep brain stimulation of the subthalamic nucleus has been reported to improve motor symptoms and decrease medication usage. However, the impact of subthalamic nucleus deep brain stimulation (STN-DBS) on sleep quality in PD patients remains to be definitively determined. This systematic review and meta-analysis, conducted following the preferred reporting items for systematic reviews and meta-analyses guidelines, aimed to clarify the effect of STN-DBS on sleep quality in PD patients. METHODS: A rigorous literature search identified 6 studies, including 1 randomized controlled trial and 5 self-controlled trials, totaling 154 patients who underwent deep brain stimulation, providing 308 pairs of data for analysis. Parkinson disease sleep scale was the primary measure of interest, while the Movement Disorder Society-sponsored revision of the unified Parkinson disease rating scale was documented in all trials. Study quality was assessed using the Newcastle-Ottawa scale. RESULTS: STN-DBS significantly improved Parkinson disease sleep scale scores (mean difference = 20.41, 95% CI: [13.03, 27.79], I² = 60.8%, P < .001), indicating enhanced sleep quality. Furthermore, a significant reduction in movement disorder society unified Parkinson disease rating scale part III scores postoperatively (mean difference = -12.59, 95% CI: [-14.70, -10.49], I² = 89.9%, P < .001) suggested improved motor function. PD medication usage was also significantly reduced postoperatively (mean difference = -314.71, 95% CI: [-468.13, -161.28], I² = 52.9%, P < .001). A sensitivity analysis confirmed the robustness of the main findings. The sample size was adequate, allowing for conclusive inferences. CONCLUSION: The present study, which comprises a comprehensive systematic review and meta-analysis, offers compelling evidence that STN-DBS can ameliorate sleep quality, augment motor function, and curtail medication consumption among individuals afflicted with PD.

Expression of multi-drug resistance-related genes MDR3 and MRP as prognostic factors in clinical liver cancer patients.

BACKGROUND/AIMS: To investigate the expression of multi-drug resistance-related genes, MDR3 and MRP, in clinical specimens of primary liver cancer and their potential as prognostic factors in liver cancer patients. METHODOLOGY: A total of 26 patients with primary liver cancer were enrolled. The expression of MDR3 and MRP genes was measured by real-time PCR and the association between gene expression and the prognosis of patients was analyzed by the Kaplan-Meier method and COX regression model. RESULTS: This study showed that increases in MDR3 gene expression were identified in cholangiocellular carcinoma, cirrhosis and HBsAg-positive patients, while MRP expression increased in hepatocellular carcinoma, non-cirrhosis and HBsAg-negative patients. Moreover, conjugated bilirubin and total bile acid in the serum were significantly reduced in patients with high MRP expression compared to patients with low expression. The overall survival tended to be longer in patients with high MDR3 and MRP expression compared to the control group. MRP might be an independent prognostic factor in patients with liver cancer by COX regression analysis. CONCLUSIONS: MDR3 and MRP may play important roles in liver cancer patients as prognostic factors and their underlying mechanisms in liver cancer are worthy of further investigation.

Inflammatory myofibroblastic tumor mimicking malignant meningioma in the middle cranial fossa: a case report.

INFLAMMATORY myofibroblastic tumor (IMT), also known as inflammatory pseudotumor or plasma cell granulomas, is an uncommon fibro-inflammatory lesion which is composed of inflammatory cells and myofibroblastic spindle cells. Its pathogenesis is still unknown. The tumor commonly occurs in the lung, upper respiratory tract, live, orbit, abdominal membrane, retroperitoneum, and genitourinary tract.It rarely involves the central nerve system, especially the middle cranial fossa. As far as we know, there are no more than 5 reports of IMT that developed in the middle cranial fossa without involving temporal bone. IMT can occur at any age but primarily affects children and young adults. It is difficult to diagnose IMT by clinical and imaging characteristics only. Here we present an 82-year-old female with intracranial IMT arising from the meninges and without involving temporal bone, which was diagnosed as malignant meningioma before operation.

A Radiosensitivity Prediction Model Developed Based on Weighted Correlation Network Analysis of Hypoxia Genes for Lower-Grade Glioma.

Background and Purpose: Hypoxia is one of the basic characteristics of the physical microenvironment of solid tumors. The relationship between radiotherapy and hypoxia is complex. However, there is no radiosensitivity prediction model based on hypoxia genes. We attempted to construct a radiosensitivity prediction model developed based on hypoxia genes for lower-grade glioma (LGG) by using weighted correlation network analysis (WGCNA) and least absolute shrinkage and selection operator (Lasso). Methods: In this research, radiotherapy-related module genes were selected after WGCNA. Then, Lasso was performed to select genes in patients who received radiotherapy. Finally, 12 genes (AGK, ETV4, PARD6A, PTP4A2, RIOK3, SIGMAR1, SLC34A2, SMURF1, STK33, TCEAL1, TFPI, and UROS) were included in the model. A radiosensitivity-related risk score model was established based on the overall rate of The Cancer Genome Atlas (TCGA) dataset in patients who received radiotherapy. The model was validated in TCGA dataset and two Chinese Glioma Genome Atlas (CGGA) datasets. A novel nomogram was developed to predict the overall survival of LGG patients. Results: We developed and verified a radiosensitivity-related risk score model based on hypoxia genes. The radiosensitivity-related risk score served as an independent prognostic indicator. This radiosensitivity-related risk score model has prognostic prediction ability. Moreover, a nomogram integrating risk score with age and tumor grade was established to perform better for predicting 1-, 3-, and 5-year survival rates. Conclusions: We developed and validated a radiosensitivity prediction model that can be used by clinicians and researchers to predict patient survival rates and achieve personalized treatment of LGG.

Microstructural Periventricular White Matter Injury in Post-Hemorrhagic Ventricular Dilatation.

BACKGROUND AND OBJECTIVES: The neurological deficits of neonatal post-hemorrhagic hydrocephalus (PHH) have been linked to periventricular white matter injury. To improve understanding of PHH-related injury, diffusion basis spectrum imaging (DBSI) was applied in neonates, modeling axonal and myelin integrity, fiber density, and extra-fiber pathologies. Objectives included characterizing DBSI measures in periventricular tracts, associating measures with ventricular size, and examining MRI findings in the context of post-mortem white matter histology from similar cases. METHODS: A prospective cohort of infants born very preterm underwent term equivalent MRI, including infants with PHH, high-grade intraventricular hemorrhage without hydrocephalus (IVH), and controls (VPT). DBSI metrics extracted from the corpus callosum, corticospinal tracts, and optic radiations included fiber axial diffusivity, fiber radial diffusivity, fiber fractional anisotropy, fiber fraction (fiber density), restricted fractions (cellular infiltration), and non-restricted fractions (vasogenic edema). Measures were compared across groups and correlated with ventricular size. Corpus callosum postmortem immunohistochemistry in infants with and without PHH assessed intra- and extra-fiber pathologies. RESULTS: Ninety-five infants born very preterm were assessed (68 VPT, 15 IVH, 12 PHH). Infants with PHH had the most severe white matter abnormalities and there were no consistent differences in measures between IVH and VPT groups. Key tract-specific white matter injury patterns in PHH included reduced fiber fraction in the setting of axonal and/or myelin injury, increased cellular infiltration, vasogenic edema, and inflammation. Specifically, measures of axonal injury were highest in the corpus callosum; both axonal and myelin injury were observed in the corticospinal tracts; and axonal and myelin integrity were preserved in the setting of increased extra-fiber cellular infiltration and edema in the optic radiations. Increasing ventricular size correlated with worse DBSI metrics across groups. On histology, infants with PHH had high cellularity, variable cytoplasmic vacuolation, and low synaptophysin marker intensity. DISCUSSION: PHH was associated with diffuse white matter injury, including tract-specific patterns of axonal and myelin injury, fiber loss, cellular infiltration, and inflammation. Larger ventricular size was associated with greater disruption. Postmortem immunohistochemistry confirmed MRI findings. These results demonstrate DBSI provides an innovative approach extending beyond conventional diffusion MRI for investigating neuropathological effects of PHH on neonatal brain development.

Analysis of Antidepressant Quality Markers of Bupleuri Radix Before and After Vinegar-processing Based on UPLC-Q-TOF-MS and Network Pharmacology / 中国实验方剂学杂志

ObjectiveTo analyze the antidepressant quality markers（Q-Marker） of Bupleuri Radix（BP） before and after vinegar-processing by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS）， multivariate statistical analysis and network pharmacology. MethodUPLC-Q-TOF-MS was used to analyze the chemical basis of raw and vinegar-processed products of BP， and principal component analysis（PCA） orthogonal partial least squares-discriminant analysis（OPLS-DA） were used to identify the differential components in BP that changed significantly before and after vinegar-processing， which were regarded as candidate quality markers（Q-Marker）. Then the disease-drug-component-target network related to antidepressant effect of BP was constructed by network pharmacology， and the antidepressant Q-Marker of raw and vinegar-processed products of BP was determined. Rats were randomly divided into blank group， model group， fluoxetine group（2.67 mg·kg-1） and total saponin group（0.72 mg·kg-1）， except the blank group， rats in the other groups were subjected to chronic unpredictable mild stress（CUMS）. Three weeks after the start of modeling， rats in each administration group were given the corresponding dose of drugs once a day for 4 weeks， and rats in the blank and model groups were given normal saline with dose of 10 mL·kg-1. At 1 day before modeling， 21 days and 28 days after administration， body mass weighing， sucrose preference test and open field test were performed on each group . After 28 days of administration， real-time fluorescence quantitative polymerase chain reaction（Real-time PCR） was used to detect the mRNA expression levels of phosphatidylinositol 3-kinase（PI3K）， protein kinase B（Akt）， mammalian target of rapamycin（mTOR）， glycogen synthase kinase-3β（GSK-3β）， forkhead box transcription factor O3a（FoxO3a） and β-catenin in hippocampal tissues of rats in each group， while protein expression levels of PI3K， Akt， mTOR and FoxO3a in hippocampal tissues of rats in each group were detected by Western blot. ResultThere were 19 components in BP showed significant changes before and after vinegar-processing， and 9 components such as saikosaponin A， saikosaponin B1， saikosaponin B2， saikosaponin C and saikosaponin D were identified as potential Q-Marker through S-plot differential marker screening. Combined with the disease-drug-component-target network， saikosaponin A， saikosaponin B1， saikosaponin B2 and saikosaponin D were identified as antidepressant Q-Marker of raw and vinegar-processed products of BP. According to the results of pharmacodynamic tests， after 28 d of administration， compared with the blank group， the body mass， sucrose preference index and open field total score of rats in model group， fluoxetine group and total saponin group decreased significantly（P<0.01）. Compared with the model group， the body mass， sucrose preference index and open field total score in total saponin group increased significantly（P<0.01）. Compared with the blank group， mRNA expression levels of PI3K， Akt， mTOR and β-catenin in hippocampus of rats in the model group decreased significantly（P<0.05）， while mRNA expression levels of GSK-3β and FoxO3a increased significantly（P<0.05）. Compared with the model group， mRNA expression levels of PI3K， Akt， mTOR and β-catenin in hippocampus of rats in the total saponin group were increased significantly（P<0.05）， while mRNA expression levels of GSK-3β and FoxO3a decreased significantly（P<0.05）. Compared with the blank group， the protein expression levels of Akt and mTOR in hippocampus of the model group decreased significantly（P<0.01）， while the protein expression levels of PI3K and FoxO3a increased significantly（P<0.01）. Compared with the model group， the expression level of Akt in hippocampus of the total saponin group increased significantly（P<0.01）， the mTOR expression level was increased but not statistically significant， while the protein expression levels of PI3K and FoxO3a decreased significantly（P<0.01）. ConclusionThe chemical constituents of BP changed greatly after vinegar-processing， and the antidepressant Q-Marker of raw and vinegar-processed products of BP was determined by chemical basis， pharmacodynamics， network pharmacology and signaling pathway， which provided a reference for further research on quality control， pharmacodynamic substance basis and processing mechanism of BP.

Transthoracic closure of ventricular septal defects guided by transesophageal echocardiography.

BACKGROUND: This study aims to investigate the effectiveness and safety of transthoracic closure of ventricular septal defects totally guided by transesophageal echocardiography. METHODS: A total of 119 patients (62 males, 57 females; mean age 2.1±5.2 years; range, 11 months to 50 years) who underwent transthoracic closure of ventricular septal defects in our center between April 2017 and November 2018 were included. All patients were evaluated in terms of the diameter and morphological features of ventricular septal defects via transesophageal echocardiography. During the procedure, transthoracic echocardiography was used as the only guiding tool for occluder implantation. RESULTS: Of the patients, 116 underwent successful transthoracic device closure procedure. Two patients were switched to surgical repair due to new-onset aortic regurgitation in one patient and severe arrhythmias after device release in the other patient. One patient underwent a second operation for occluder migration during the hospital stay. In the first attempt, 106 ventricular septal defect occluders were correctly positioned. Transthoracic echocardiography revealed the insecure position or significant residual shunting in 10 patients. The original device was replaced with an asymmetric device or a more extensive occluder, and satisfactory results were finally obtained. No complications such as new-onset aortic regurgitation, residual shunt, complete heart block, or device dislodgement occurred during follow-up. CONCLUSION: Transthoracic closure of ventricular septal defects under the total guidance of transthoracic echocardiography is a safe and effective method.

Logistics operation and management of public hospitals based on the"one center,four platforms"model / 现代医院

Objective To evaluate the effectiveness of a hospital logistics operation and management based on the"one center,four platforms"model.Methods In line with the grading evaluation standards for hospital intelligent management,we used technologies such as big data,Internet of Things,Internet Plus,and artificial intelligence to develop a"one center,four platforms"model.This model consisted of a logistics intelligent operation and maintenance management center,an equipment control information platform,a security prevention information platform,an energy consumption monitoring information platform,and an operation management information platform.Results The equipment fault resolution capability,enhanced by the"smart linkage",showed a significant improvement.In 2022,false alarms decreased by 28.63%compared to 2021,with high-level and ordinary-level alarms decreasing by 69.53%and 33.15%,respectively.The"one-stop"logistics service capability was signifi-cantly improved,as indicated by a 2.92%decrease in maintenance frequency in 2022 compared to 2021.This improvement was further reflected in the quality of maintenance and a decrease in the repeated maintenance occurrences.The energy consumption control capability,based on the"data mining",showed a significant improvement,with an 8.71%year-on-year decrease in en-ergy expenditure of ten thousand yuan in 2022 compared to 2021.Conclusion The"one center,four platforms"model can sig-nificantly enhance the efficiency of logistics operation and maintenance management.

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The main protease (Mpro) of SARS-CoV-2 is an attractive target in anti-COVID-19 therapy for its high conservation and major role in the virus life cycle. The covalent Mpro inhibitor nirmatrelvir (in combination with ritonavir, a pharmacokinetic enhancer) and the non-covalent inhibitor ensitrelvir have shown efficacy in clinical trials and have been approved for therapeutic use. Effective antiviral drugs are needed to fight the pandemic, while non-covalent Mpro inhibitors could be promising alternatives due to their high selectivity and favorable druggability. Numerous non-covalent Mpro inhibitors with desirable properties have been developed based on available crystal structures of Mpro. In this article, we describe medicinal chemistry strategies applied for the discovery and optimization of non-covalent Mpro inhibitors, followed by a general overview and critical analysis of the available information. Prospective viewpoints and insights into current strategies for the development of non-covalent Mpro inhibitors are also discussed.

GDNF-secreting human neural progenitor cells increase tyrosine hydroxylase and VMAT2 expression in MPTP-treated cynomolgus monkeys.

Human neural progenitor cells (hNPCs) have been proposed as a potential source of cells for ex vivo gene therapy. In this pilot study, three 5-year-old female cynomolgus monkeys received a single intracarotid infusion of MPTP, followed 1 week later by MRI-guided stereotaxic intrastriatal and intranigral injections of male hNPCs transgenic for GDNF. Immunosupression with oral cyclosporine (30-40 mg/kg) began 48 h before hNPC transplants and continued throughout the study. We monitored the animals using a clinical rating scale (CRS). Three months postsurgery, we euthanized the animals by transcardiac perfusion, then retrieved and processed their brains for morphological analysis. Our findings include the following. 1) hNPCs survived and produced GDNF in all animals 3 months postsurgery. 2) hNPCs remained in the areas of injection as observed by GDNF immunostaining and in situ hybridization for the human Y chromosome. 3) A "halo" of GDNF expression was observed diffusing from the center of the graft out into the surrounding area. 4) We observed increased TH- and VMAT2-positive fibers in areas of GDNF delivery in two of the three animals. The two animals with TH- and VMAT2-positive fibers also showed reductions in their CRS scores. 5) Some GFAP-positive perivascular cuffing was found in transplanted areas. 6) General blood chemistry and necropsies did not reveal any abnormalities. Therefore, we conclude that hNPCs releasing GDNF may be a possible alternative for intracerebral trophic factor delivery in Parkinson's disease.

Identification and management of sepsis associated-acute kidney injury / 中华危重病急救医学

At present, the diagnosis of sepsis associated-acute kidney injury (SA-AKI) mainly relies on monitoring urine volume or serum creatinine (SCr) levels. Due to decreased renal blood supply and the use of diuretics, the diagnosis is intrusive and non-specific. Early identification of the clinical process of SA-AKI and effective management can restore renal function as soon as possible and improve outcomes. This paper discusses the epidemiology, diagnostic limitations, pathophysiological mechanism, treatment and prognosis of SA-AKI. Approximately 30% of patients with sepsis were found to develop acute kidney injury (AKI), and 50% of patients with AKI in the intensive care unit (ICU) were found to have sepsis. Once a diagnosis of SA-AKI is made, close monitoring and timely organ support therapy should be combined to prevent further kidney injury. SA-AKI can be reversed early in the first week after admission, and the prognosis is good. The main mechanisms of organ injury in sepsis are reduced perfusion of bilateral glomeruli, impaired inflammatory response, metabolic adaptation and microcirculation. Etiological control and antibiotic application early play important roles in sepsis management. In addition, fluid resuscitation, vasopressors, early use of renal replacement therapy (RRT), and blood purification are important prognostic factors of SA-AKI.

Analysis of practice effect of teaching reform in the course of nursing education based on Rain Classroom / 中华医学教育探索杂志

Objective:To investigate the application effect of blended teaching mode based on Rain Classroom in the course of nursing education.Methods:The nursing teaching class in 2019 was set as the observation group ( n=20), which adopted blended teaching mode combining classroom teaching and online learning of Rain Classroom platform. The teaching class with the same number of students in the same period in 2018 was set as the control group ( n=20), which implemented the traditional classroom teaching mode. SPSS 22.0 was used for statistical processing, and independent-samples t-test was used to analyze the results of seminar, simulated teaching and final theoretical examination of the two classes of students and the evaluation of the teaching effect of the course. Results:There was no significant difference between the two groups in the results of simulated teaching ( t=0.21, P = 0.834). The scores of seminar [(91.18±1.20), t=3.09, P<0.05] and final theoretical examination [(78.63±6.28), t=3.33, P<0.05] in the observation group were significantly higher than those in the control group. The scores of information retrieval and processing ability ( t=-3.33, P < 0.05), problem finding ability ( t=-2.17, P < 0.05), independent thinking ability ( t=-2.53, P < 0.05), knowledge integration ability ( t=-3.86, P < 0.001), self-learning ability ( t=-3.12, P<0.05), the sense of identity to the role of nursing teachers ( t=-2.53, P < 0.05), the awareness of active learning ( t=-3.13, P < 0.05) and the attitude of lifelong learning ( t=-4.46, P < 0.001) in the experimental group were higher than those in the control group. Conclusion:The blended teaching based on Rain Classroom is conducive to the cultivation of students' inquiry learning ability and deep learning of theoretical knowledge, and promotes the effective achievement of curriculum teaching objectives.

Anti-tumor Effect of Alkaloids of Chinese Medicine： A Review / 中国实验方剂学杂志

Malignant tumors， with the increasing crude morbidity and mortality year by year， have become the major diseases threatening human health. The conventional therapeutic drugs against tumors have serious adverse reactions， which can cause a heavy burden on patients. The active components of Chinese medicine can effectively inhibit tumor growth， improve the quality of life of patients， and have few toxic and side effects. Alkaloids of Chinese medicine are natural organic compounds widely existing in a variety of Chinese herbal medicines. In recent years， they have attracted more and more attention because of their anti-tumor effect. The anti-tumor mechanisms of alkaloids of Chinese medicine mainly include the induction of apoptosis， inhibition of tumor cell migration and invasion， suppression of proliferation， induction of autophagy of tumor cells， cell cycle arrest， inhibition of tumor angiogenesis， regulation of microRNA， and modulation of immunity. In addition， Chinese medicine alkaloids can also reverse tumor drug resistance and reduce the stemness of tumor stem cells. Alkaloids of Chinese medicine can regulate the phosphatidylinositol 3-kinase/protein kinase B （PI3K/Akt）， c-Jun N-terminal kinase （JNK）， p38 mitogen-activated protein kinase （p38 MAPK）， mammalian target of rapamycin （mTOR）， Notch， Hedgehog， Wnt/β-catenin， and other signaling pathways to participate in the processes of tumor proliferation， invasion and metastasis， autophagy and apoptosis， and affect the occurrence and development of tumors in multiple links and ways. The derivatives and nano-preparations of alkaloids can improve the solubility， utilization， and anti-tumor activity of alkaloids， bringing a broader prospect for the clinical application of alkaloids. This review summarized the recent anti-tumor research on alkaloids， their representative derivatives， and nano-preparations to provide references for the in-depth research on the anti-tumor effect of alkaloids.

Estimation of atmospheric environmental radiation capacity in an isotope industrial park / 中国辐射卫生

Objective To study and estimate the public dose constraint and the atmospheric radiation capacity of an isotope industrial park, and to provide a basis for management of radioactive effluent discharge in isotope industrial parks. Methods We collected the natural environment data, meteorological data, and population distribution and dietary data as well as the source terms of radioactive airborne effluents of an isotope industrial park. The public dose constraint value of the isotope industrial park was determined based on the natural environmental radiation hazard level. The atmospheric environmental radiation capacity of the industrial park was estimated by the all-pathways method. Results The public dose constraint value of the industrial park was 0.2 mSv/a. At the end of industrial park planning, the maximum individual effective dose to the public caused by airborne effluent discharge was 1.07×10−6 Sv/a, which accounted for 0.54% of the public dose constraint value. The proportions of discharges of airborne radionuclides to respective environmental radiation capacities ranged from 0.04% to 4.34%. Conclusion The determined public dose constraint value of the isotope industrial park can be used as the total radiation capacity of the regional atmospheric environment to constrain the discharge of radioactive effluents. The environmental radiation capacity of each radionuclide can be estimated by the all-pathways method considering the comprehensive impact of radionuclide discharges, which is suitable for the control and management of isotope production enterprises in industrial parks.

Effect of various intracanal materials on the diagnostic accuracy of cone-beam computed tomography in vertical root fractures / 北京大学学报(医学版)

OBJECTIVE@#To study the effect of various intracanal materials on the accuracy of oral maxillofacial cone-beam computed tomography (CBCT) for the diagnosis of vertical root fracture (VRF).@*METHODS@#A total of twenty-four structurally intact single root canal dried and isolated teeth extracted for orthodontic treatment or periodontal disease were collected. The teeth were decrowned along the cemento-enamel junction (CEJ) and then used as samples for the study after conventional root canal preparation and post preparation. The 24 samples were divided into two groups with 12 samples in each group. Group A was the control group (no VRF group). According to intracanal materials, they were divided into five subgroups: blank group, fiber post group, gutta-percha point group, titanium post group and gold-palladium post group. Group B was the experimental group (VRF group), and subgroups were grouped as above. The VRF model was prepared by a unified method in the VRF group: the root was completely fractured in the buccolingual direction with a custom root canal nail and then cemented and reset. The control group was not subjected to the simulation of VRF. Titanium post and gold-palladium post were made according to the individuality of the root canal preparation, and the tightness of the post to the root canal wall was confirmed by X-ray radiograph. Then all the samples were scanned by CBCT in the isolate swine mandibular alveolar sockets. The diagnostic accuracy was statistically analyzed via blind interpretation by experienced endodontic specialists and oral and maxillofacial medical imaging specialists.@*RESULTS@#The accuracy of the diagnosis of VRF in the blank group, fiber post group, gutta-percha point group, titanium post group, and gold-palladium post group in CBCT was 95.83%, 91.67%, 87.50%, 79.17%, and 45.83%, respectively. Compared with the blank group, the differences were not statistically significant in the fiber post group (P>0.999), the gutta-percha point group (P=0.500) and the titanium post group (P=0.125). The lowest diagnostic accuracy of VRF was found in the gold-palladium post group, and the difference was statistically significant compared with all other groups (P < 0.001).@*CONCLUSION@#Various intracanal materials have different degrees of influence on the diagnostic accuracy of VRF diagnosis in CBCT. The influence of fiber post, gutta-percha point and titanium post was small, while the influence of gold-palladium post was significant.

Mechanical Behavior of Radial Support of a Novel Balloon Expandable Tapered Stent / 医用生物力学

Objective To explore influences of the taper and connecting rib form on supporting performance of the stent, and provide an important scientific basis for structural design and clinical selection of the tapered stent. Methods A nonlinear finite element model for radial support performance of a novel balloon-expandable tapered stent was constructed, and the radial stiffness (RS) and stress distributions of the stent at different tapers (0°, 0.565°and 1.13°) and with different structural forms of stent linker (V-shape, I-shape, C-shape, S-shape, M-shape) were analyzed by plane compression. The relationship between structural design of the vascular stent and its radial support performance was studied. Results The RS of 0°stent, 0.565°stent, 1.13° stent was 2.51, 1.61, 0.85 N/mm, respectively. The RS of 0.565°stent and 1.13° stent was 35.86% and 66.14% lower than that of 0°stent (round straight stent), respectively. Except that the RS of C-shape linker stent was 1.48 N/mm, the RS of I, M, S and V-shape linker stents was not significantly different, which was 2.51, 2.61, 2.41, 2.52 N/mm, respectively, indicating that radial compression resistance of these four linker stents was almost the same. Conclusions Compared with traditional round straight stents, the RS of tapered stents will decrease, and the RS of stents will gradually decrease with the the taper increasing. Among all stent types in this study, except C-shape linker stents, the RS of other linker shapes has little effect on the RS of stents. The radial support performance of the stent can be improved by reducing the taper of the tapered stent, without changing the form of stent connecting ribs.