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In recent years, PD-1 immune checkpoint inhibitors based on monoclonal antibodies have revolutionized cancer therapy, but there still exist unresolved issues, such as the high cost, the relatively low response rates, and so on, compared with small-molecule drugs. Herein a type of pyrrole-imidazole (Py-Im) polyamide as a small-molecule DNA binder was designed and synthesized, which could competitively bind to the same double-stranded DNA stretch in the PD-L1 promoter region as the STAT3 binding site and thus downregulate PD-L1 expression. It was demonstrated that the Py-Im polyamides directly caused apoptosis in tumor cells and retarded cell migration in the absence of T cells through inhibiting the Akt/caspase-3 pathway. Also, in a coculture system, they enhanced the T-cell-mediated killing of tumor cells by the reversal of immune escape. Because such polyamides induced antitumor effects via both immune and nonimmune pathways, they could be further developed as promising PD-L1 gene-targeting antitumor drugs.

Storm geysers increasingly occur in sewer systems under climate change and rapid urbanization. Mitigation measures are in great demand to avoid safety problems. In this study, three-dimensional computational fluid dynamics models of single-inlet and multi-inlet systems were established to investigate geysering induced by rapid filling and assess the effectiveness of potential mitigation methods. The modeling results suggest that increasing the capacity of the downstream pipe before the inflow front reaches the chamber can effectively reduce the maximum geyser pressure. The peak pressure can be significantly mitigated when the chamber size is designed with care and the drop height between the upstream and downstream pipes is reduced. A diversion deflector with air vents and an orifice plate at the riser top end can alleviate the maximum pressure by about 65% with about 75% of the entrapped air being released. The peak pressure during the geyser event in the multi-inlet model is less than that of a single-inlet model under the same total inflow condition, but more water can be released. HIGHLIGHTS A small drop height between the connecting pipes can effectively reduce the maximum pressure during rapid filling.; Mitigation measures including flow deflectors and orifice plates were studied to alleviate geyser intensity.; Intermittent air–water jets can be generated much more easily in a system with multiple inlets, and the peak pressure is generally small but more water can be released.

Purpose: To propose a new imaging classification based on cerebral angiography to determine the segment and length of occlusion and the condition of the proximal and distal lumen of the occluded segment.Methods: This retrospective study included patients with non-acute carotid artery occlusion (NACAO) who visited XXX Hospital (01/2017-12/2020). The lesions were classified according to the segment and length of carotid artery occlusion and the proximal and distal lumen of the occluded segment. Results: Type IV is not recommended for endovascular recanalization, and patients with types I (10/24, 41.7%), II (7/24, 29.2%), and III (7/24, 29.2%) were included. The recanalization success rate was 87.5% (21/24; Type I, 10/10; Type II, 7/7; Type III, 4/7; P=0.017). The incidence of perioperative complications was 25.0% (6/24; Type I, 0/10; Type II, 2/7; Type III, 4/7; P=0.038). The re-occlusion rate was not significantly different among the three groups (P=0.284). The average modified Rankin Scale (mRS) score in the success group was lower than before operation (P=0.012), but not in the failure group (P=0.317). Conclusion: The new classification based on cerebral angiography is helpful to screen patients with drug-refractory NACAO with a high success rate and low complications of intra-tube recanalization.

Purchasing a house in origin cities or towns has become a new trend in housing trajectories for rural migrants in China, whereas previous studies focus mainly on determinants of housing tenure for ...

At present, cancers have been causing deadly fears to humans and previously unpredictable losses to health. Especially, lung cancer is one of the most common causes of cancer-related mortality accounting for approximately 15% of all cancer cases worldwide. While Non-Small Cell Lung Carcinomas (NSCLCs) makes up to 80% of lung cancer cases. The patient compliance has been weakening because of serious drug resistance and adverse drug effects. Therefore, there is an urgent need for the development of novel structural agents to inhibit NSCLCs. Nitrogen-containing heterocyclic compounds exhibit wide range of biological properties, especially antitumor activity. We reviewed some deadly defects of clinical medicines for the lung cancer therapy and importance of nitrogen based heterocyclic derivatives against NSCLCs. Nitrogen heterocycles exhibit significant antitumor activity against NSCLCs. Nitrogen heterocyclic hybrids could be developed as multi-target-directed NSCLC inhibitors and it is believed that the review is significant for rational designs and new ideas in the development of nitrogen heterocyclic-based drugs.

The influence of temperature on a variety of physiological or chemical processes has generated considerable interest, and recently noninvasive lanthanide-incorporated optical thermometers have been considered as promising candidates for monitoring its changes at different scales. Herein, a novel Bi3+-activated Sr3-xGdxGaO4+xF1-x phosphor with tunable color has been constructed by a cooperative cation-anion substitution strategy with to the replacement of [Sr2+-F-] by [Gd3+-O2-]. When x = 0, the sample Sr3GaO4F/Bi3+ possesses a peak wavelength at 438 nm, and this value will shift to 470 nm if x is equal to 1 (Sr2GdGaO5/Bi3+). In addition, photoluminescence tuning from blue to red has been realized successfully by an efficient Bi3+ → Eu3+ energy migration model in Sr2.6Gd0.4GaO4.4F0.6 samples. The specific Bi3+ → Eu3+ energy transfer has been explained by dipole-dipole interactions derived from a model of the Dexter pathway. Intriguingly, the two dopants (a blue signal from Bi3+ and a red signal from Eu3+) possess different thermal responses to increasing temperature. Accordingly, the intensity ratio values are sensitive to the temperature changes. The energy level cross relaxation causes the quenching effect of Bi3+, and the multi-phonon de-excitation mode leads to the thermal quenching of Eu3+. At room temperature (298 K), the determined maximum relative sensitivity (Sr) is 1.27% K-1. Moreover, the absolute sensitivity (Sa) is 0.067 K-1 since the temperature is elevated to 523 K. The collected results are superior to most of the reported optical thermometry materials.

Intracranial atherosclerotic stenosis (ICAS) is one of the leading causes of stroke worldwide. Current diagnostic evaluations and treatments remain insufficient to assess the vulnerability of intracranial plaques and reduce the recurrence of stroke in symptomatic ICAS. On the other hand, asymptomatic ICAS is associated with an increased risk of cognitive impairment. The pathogenesis of ICAS related cognitive decline is largely unknown. The aim of SICO-ICAS study (stroke incidence and cognitive outcomes of ICAS) is to elucidate the pathophysiology of stroke and cognitive impairment in ICAS population, comprehensively evaluating the complex interactions among life-course exposure, genomic variation, vascular risk factors, cerebrovascular burden and coexisting neurodegeneration.SICO-ICAS is a multicenter, prospective, observational cohort study. We aim to recruit 3,000 patients with symptomatic or asymptomatic ICAS (50% or occlusion) who will be followed up for ≥12 months. All participants will undergo pre-designed magnetic resonance imaging packages, blood biomarkers testing, as well as detailed cognitive domains assessment. All participants will undergo clinical visits every 6 months and telephone interviews every 3 months. The primary outcome measurement is ischemic stroke or cognitive impairment within 12 months after enrollment.This study will establish a large prospective ICAS cohort, hopefully discover new biomarkers associated with vulnerable intracranial plaques, identify subjects at high risk for incident ischemic stroke or cognitive impairment, and eventually propose a precise diagnostic and treatment strategy for ICAS population.Chinese Clinical Trials Register ChiCTR2200061938.

In our work, 19 novel 4,5-diazafluorene derivatives (11a-d, 12a-d, 13a-d, 14a-c, 15c, 16a-c) bearing a 1,3-disubstituted pyrazol/thioxothiazolidinone or thioxothiazolidinone-oxadiazole moieties were designed, synthesized, preliminarily explored for their antitumor activities and in vitro mechanism. All compounds showed different values of antiproliferative activity against A549, AGS, HepG2 and MCF-7 cell lines through CCK-8. Especially, the compound 14c exhibited the strongest activity and best selectivity against A549 cells with an IC50 1.13 μM and an SI value of 7.01 relative to MRC-5 cells, which was better than cisplatin (SI = 1.80) as a positive control. Experimental results at extracellular level demonstrated that compounds 14a-c could strongly interact with the G-quadruplex(es) formed in a 26 nt telomeric G-rich DNA, in particular, the 14c exhibits quite strong binding affinity with an association equilibrium constant (KA) of 7.04(±0.16) × 107 M−1 and more than 1000-fold specificity to G4-DNA over ds-DNA and Mut-DNA at the compound/G4-DNA ratio of 1:1. Further trap assay ascertained that compounds 14a-c owned strong inhibitory ability of telomerase activity in A549 cells, suggesting that these compounds have great possibility to target telomeric G-quadruplexes and consequently indirectly inhibit the telomerase activity. In addition, it is worthy of note that the remarkable inhibitory effects of 14a-c on the mobility of tested cancer cells were observed by wound healing assays. Furthermore, molecular docking and UV–Vis spectral results unclose the rationale for the interaction of compounds with such G-quadruplex(es). These results indicate that the growth and metastasis inhibition of cancer cells mediated by these 4,5-diazafluorene derivatives possibly result from their interaction with telomeric G-quadruplexes, suggesting that 4,5-diazafluorene derivatives, especially 14c, possess potential as anticancer drugs.

Teaching artificial intelligence (AI) is an emerging challenge in global school education. There are considerable barriers to overcome, including the existing practices of technology education and teachers’ knowledge of AI. Research evidence shows that studying teachers’ experiences can be beneficial in informing how appropriate design in teaching sustainable AI should evolve. Design frames characterize teachers’ design reasoning and can substantially influence their AI lesson design considerations. This study examined 18 experienced teachers’ perceptions of teaching AI and identified effective designs to support AI instruction. Data collection methods involved semi-structured interviews, action study, classroom observation, and post-lesson discussions with the purpose of analyzing the teachers’ perceptions of teaching AI. Grounded theory was employed to detail how teachers understand the pedagogical challenges of teaching AI and the emerging pedagogical solutions from their perspectives. Results reveal that effective AI instructional design should encompass five important components: (1) obstacles to and facilitators of participation in teaching AI, (2) interactive design thinking processes, (3) teachers’ knowledge of teaching AI, (4) orienteering AI knowledge for social good, and (5) the holistic understanding of teaching AI. The implications for future teacher AI professional development activities are proposed.

Rural–urban migrants in China often experience poor living conditions and are less likely to be homeowners than urban–urban migrants. This study aims to investigate whether the homeownership gap between rural–urban migrants and urban–urban migrants in China vary by income. We explore the homeownership gap between the two migrant groups using the National Migrants Population Dynamic Monitoring Survey in 2014. Our findings show that the homeownership gap between rural–urban migrants and urban–urban migrants vary by income, and this gap is larger for high-income groups than for low-income groups. The estimations also demonstrate that social security insurance may act as the transmission channel, indicating a stratification process.

Background: Rural-urban migrants often suffer overrepresented health risks but have less access to public health services，while the homeownership status in China may play a vital role in the attainment of local welfare. However, the effect of homeownership on the public health services utilization is still understood. This study aims to address the causal effect of homeownership on the utilization of local public health services among rural migrants in China. Three issues are addressed to discuss: Whether the homeownership produces a significant effect on the utilization of local public health services or not? Are there any interaction effect between homeownership and location of household/ healthcare center? Does the homeownership effect vary by employment status, migration duration and migration patterns?Methods: The dataset from the 2017 National Migrants Population Dynamic Monitoring Survey (NMPDMS-2017) is applied to explore the direct effect of homeownership on the utilization of local public health services. The Logit regression is conducted to discuss the associations, while the IV estimation developed by Lewbel (2012) is employed to correct the endogeneity of homeownership. Additionally, the Logit regressions are also performed to explore the interaction effect and heterogeneous effect.Results: The Logit estimations reveal that the homeownership is positive with the establishment of health record (OR=1.1926; 95% CI=1.154,1.2325) and the attendance of health education (OR=1.1883; 95% CI=1.1506,1.2271) ,while IV estimations also confirms that the homeownership has a positive effect on the establishment of health record (Coefficient=0.0222; 95% CI=0.0121, 0.0323) and the health education access (Coefficient=0.0241; 95% CI=0.0139, 0.0343).The interaction term of homeownership and household location (Coefficient=1.4141; 95% CI= 1.2453, 1.6057) as well as the interaction between homeownership and healthcare center location (Coefficient=1.1476; 95% CI= 1.0491, 1.2554) are related with the increased establishment of health record establishment, whereas only the interaction of homeownership and household location shows significant correlations in the health education model(Coefficient=1.2186; 95% CI=1.0734, 1.3794).Conclusion: The homeownership produces a positive effect on the utilization of local public health services among rural migrants in China. Moreover, the homeownership may play a greater role along with the geographical accessibility.

Background: Most of employees in urban China have experienced a heavy commuting burden ，which has become an urgent issue that should be solved in the process of promoting the new urbanization strategy. However, not only has the exploration of relationship between commuting and sickness absence been still scant in China, but also there is no discussion made to analyze the mechanism linking the commuting time and sickness absence. To address these gaps, this study firstly investigates the commuting-absence effect as well as the potential transmission channel between them. Methods: Using a unique dataset of 2013 Matched Employer-Employee Survey (CMEES) in China, we apply the zero-inflated negative binomial model to explore the nexus between the commuting and sickness absence. To discuss the potential mechanism linking commuting and sickness absence in the context of China, the estimations of the impact of the commuting on health-related outcomes and work efforts are performed to confirm transmission channels of commute-absence effect by the OLS and Logit regression model. Results: The empirical results reveal that a longer commute has a positive effect on sickness absences, while it is still robust against several specifications. More importantly, the commuting-absence effect is mainly transmitted through health-related outcomes of employees, whereas we cannot find evidence that the effect is transmitted through shirking behavior s. Additionally, the heterogeneous effects of commuting-absence are differentiated across Hukou status, gender, pattern of commuter travel, scale of cities and types of enterprises . Conclusion: The long commute induces to lower productivities through the sickness absence, that is, the longer journey from home to work is positively related with the increasing sickness absence, which keeps in consistency with previous studies. And the potential effect of commute-sickness absence is mainly transmitted through their health-related outcomes.

At present, diseases resulting from various reasons have been causing deadly fears to humans and previously incogitable losses to health. Meanwhile, the patient compliance has been weakening because of drug resistance and serious drug adverse effects. There is therefore an urgent need for the development of novel structural agents. Rhodanine derivatives have exhibited wide biological activities, as well as significant industrial applications, which suggests that rhodanine heterocycle represents a key structural motif in heterocyclic chemistry and occupies a prominent position in drug discovery. Here, we review some deadly defects of clinical medicines to the therapy of diseases and important advances on rhodanine derivatives in drug researches (e.g. as anti-diabetic, anti-viral, antiinflammatory, anti-microbial, anti-tumor agents and inhibitors for Alzheimer Disease), indicating that rhodanine heterocycle could be used as a significant pharmacophore to develop novel pharmacological active molecules. It is believed that the review is of importance for new ideas in the development of and rational designs of rhodanine-based drugs.

In the plant leaf classification, leaf representation with traditionally handcrafted features is difficult to reveal its complex shape and texture. In this paper, we proposed a novel plant leaf classification method based on convolutional neural network (CNN) due to its powerful capability of feature extraction and classification. In our method, a ten-layer CNN was constructed for plant leaf classification. In order to improve the classification, sample augment for leaf was applied to the images to enlarge the database. The visualization was utilized for analyzing the factors influencing the accuracy rate. The experimental results on leaf database Flavia with 4,800 leaf images and 32 kinds of leaf showed that the proposed method achieved a high overall accuracy with 87.92%.

Background: An alarming increment in pathogenic resistance to existing anti-microbial agents is a serious problem and the treatment of these bacterial infections is becoming increasingly challenging. Therefore, there is an urgent need to develop novel antimicrobial agents. Objective: As a part of our ongoing studies toward the development of novel antibacterial agents, the synthesis and antibacterial activity of a series of (Z)-5-((3-phenyl-1H-pyrazol-4-yl)methylene)-2-thioxothiazolidin-4-one derivatives will be discussed in this study. Method: (Z)-5-((3-phenyl-1H-pyrazol-4-yl)methylene)-2-thioxothiazolidin-4-one derivatives were designed, synthesized and evaluated for antibacterial activity. The structures were confirmed by IR, 1H NMR, 13C NMR and mass spectrometry. All of the synthesized compounds were evaluated in vitro using a 96-well microtiter plate and a serial dilution method to obtain their minimum inhibitory concentration (MIC) values against a variety of different strains, including multidrug-resistant clinical isolates. Results: The antibacterial test in-vitro showed that most compounds in series 7 and 9 exhibited significant inhibitory activities against anaerobic bacteria (Streptococcus mutans) strains with a MIC value of 1 µg/mL. Compounds 7c and 9c showed the most potent activity against MRSA (3167 and 3506) with a minimum inhibitory concentration (MIC) value of 1 µg/mL, which is equivalent to moxifloxacin and greater than gatifloxacin, oxacillin and norfloxacin. Additionally, compound 9c showed potent antibacterial activity against Bacillus subtilis (aerobic bacteria) with a MIC value of 2 µg/mL. Conclusion: The work suggests that these type of rhodanine compounds had a better potent activity against MRSA compared with other perviously reported rhodanine derivatives, which might provide a valuable information for the development of new antibacterial agents against multidrug-resistant clinical isolates MRSA.

The objectives of this study were to examine the correlation between the level of serum inflammatory markers and the stability of carotid plaques in patients with ischemic cerebrovascular disease and to assess the ability of each inflammatory marker to identify vulnerable carotid plaques.For the early identification of vulnerable carotid plaques, 65 patients with carotid plaques were divided into a stable plaque group (n = 21) and an unstable plaque group (n = 44) according to magnetic resonance imaging characteristics. The unstable plaque group was divided into an unstable unruptured plaque group (n = 29) and an unstable ruptured plaque group (n = 15) according to whether the fibrous cap was ruptured. The levels of serum soluble cluster of differentiation 40 ligand (sCD40L), matrix metalloproteinase (MMP)-9, and MMP-2 were measured by enzyme-linked immunosorbent assay.The levels of serum sCD40L and MMP-9 in the unstable plaque group, the unstable unruptured plaque group and the ruptured plaque group were significantly higher than those in the stable plaque group (P0.05). There was no significant difference in the MMP-2 level between the stable plaque group and unstable plaque group (P = 0.056). The MMP-2 levels in the stable plaque group, unstable unruptured plaque group, and ruptured plaque group were not different (P = 0.095). The carotid plaques and the positive rate of MMP-9 of ≥84.09 ng/mL were statistically significant, suggesting increased vulnerability.Serum levels of sCD40L and MMP-9 are associated with the stability of carotid plaques. Higher levels of serum sCD40L and MMP-9 may suggest that the plaques are vulnerable or have ruptured.

A novel series of 2-(1H-pyrazol-4-yl)-1H-imidazo[4,5-f][1,10]phenanthrolines were designed, synthesized and evaluated for their antitumor activity against lung adenocarcinoma by CCK-8 assay, electrophoretic mobility shift assay (EMSA), UV-melting study, wound healing assay and docking study. These compounds showed good inhibitory activities against lung adenocarcinoma. Especially compound 12c exhibited potential antiproliferative activity against A549 cell line with the half maximal inhibitory concentration (IC50) value of 1.48 μM, which was a more potent inhibitor than cisplatin (IC50 = 12.08 μM) and leading compound 2 (IC50 = 1.69 μM), and the maximum cell inhibitory rate being up to 98.40%. Moreover, further experiments demonstrated that compounds 12a–d can strongly interact with telomeric DNA to stabilize G-quadruplex DNA with increased ΔTm values from 12.44 to 20.54 °C at a ratio of DNA to compound 1:10. These results implied that growth inhibition of A549 cells mediated by these phenanthroline derivatives is possibly positively correlated to the fact their interaction with telomeric G-quadruplexs.

To explore the feasibility, safety and efficacy of endovascular reconstructive treatment by multiple overlapping stents with or without coils.Totally 17 patients of vertebrobasilar fusiform aneurysms treated by multiple overlapping stents with or without coils between September 2011 and September 2015 in Department of Neurosurgery, Beijing Hospital were retrospectively reviewed. There were 15 male and 2 female patients with mean age of (47±13) years. Clinical manifestations included subarachnoid hemorrhage in 5 patients, cerebral ischemia or infarction in the posterior circulation in 5 patients, mass effect accompanied with brainstem infarction in 1 patients, headache or dizziness in 4, and incidental findings in 2 patients. Aneurysm located in intracranial vertebral artery in 11 patients, vertebrobasilar junction in 2 patients, and basilar trunk in 4 patients. Mean aneurysmal size was 18.5 mm×8.0 mm(length×width).Sole stenting with overlapping stents was performed in 8 patients, and overlapping stents with coils was applied in 9 patients. Post-procedural hemorrhage occurred in a patient with a giant basilar trunk fusiform aneurysm and led to death. The 16 surviving patients were clinically followed up for a mean of 21.1 months. One patient had a modified Rankin score of 4, and the other patients had a good recovery. Among 15 patients with a mean angiographic follow-up of 8.6 months, 9 patients had their aneurysms further thrombosed, 3 patients were stable, and 3 patients with a recurred aneurysm. Final complete occlusion was achieved in 7 patients.Reconstructive treatment by overlapping stents with or without coils is feasible and relative safe in vertebrobasilar fusiform aneurysms.

Let (W,S) be a Weyl group of type Bn. In this paper, we find certain nontrivial distinguished involutions in the two-sided cell Ωt of W with a-value [Formula: see text] for 1≤ 2t ≤ n and n even (resp., [Formula: see text] for 1≤ 2t < n and n odd). Besides, for 1≤ i1< ⋯ < it≤ n-1, let Li1⋯ it be a left cell of W with a-value t2 and R(Li1⋯ it) ={si1,…,sit}. There are only two involutions y(i1,i1)⋯ y(it-1,it-1) sit and y(i1,i1)⋯ y(it,it) in the left cell Li1⋯ it. We prove that the former (resp., latter) is a distinguished involution in the left cell Li1⋯ it for t odd (resp., even).

To evaluate the short-term outcome of single stenting technique for unruptured, wide-necked, tiny aneurysms of the anterior circulation.Eleven unruptured, wide-necked, tiny aneurysms of the anterior circulation were treated by a single stent deployed in the parent artery between January 2008 and July 2013 in Department of Neurosurgery in Beijing Hospital. The maximum diameter of the aneurysms ranged from 2.0 to 3.0 mm, mean (2.4 ± 0.4) mm, and the dome-to-neck ratios were all ≤ 1.2. The locations were clinoid segment of internal carotid artery (n=2), posterior communicating artery origin (n=4), anterior choroidal artery origin (n=2) and middle cerebral artery bifurcation (n=3). All internal carotid aneurysms were located in the medial and/or ventral wall of the internal carotid artery. The rate of aneurysm obliteration and rupture during follow-up was obtained by repeat angiography and clinic or telephone interview respectively.Sole stent placement in the parent artery was intentionally performed for nine aneurysms, while attempt of coiling after stent deployment for the other two aneurysms failed due to unsuccessful microcatherization. Ten stents were successfully deployed, of which one was used to treat two tandem lesions simultaneously. Only one aneurysm became smaller immediately postprocedure. No perioperative complications occurred. Angiographic follow-up after a mean period of (13 ± 6) months (range 8-24 months) revealed that 8 aneurysms did no change in size, 2 became smaller and only one was totally occluded. Asymptomatic in-stent stenosis of the parent artery was found in all 3 shrinking or occluded aneurysms. No aneurysm rupture was observed in the clinical follow-up.For those unruptured, wide-necked, tiny aneurysms arising at branching sites in the anterior circulation, single stenting technique seems to be a safe alternative treatment, while the short-term rate of aneurysm occlusion is low.

Coumarins are oxygen-containing heterocyclic compounds, which is an important type of compounds in the discovery of bioactive molecules. Some work on the synthesis of bioactive coumarins has been done by other groups. Meanwhile, many synthetic methodologies have been put forward to construct skeleton of coumarins. Results: herein, typical methods constructing coumarin and its derivatives along with multifarious biological activity compounds in vitro and in vivo are summarized, which is of value for design, synthesis and biological application of coumarins. Keywords-Coumarin; heterocyclic compound; synthesis; methodology; biological activity.

In the hydrostatic thrust bearing with open-loop quantity oil supply system for the heavy NC machine tool, the time-variable oil viscosity and the loads will cause the lubricant film thickness deviating from the optimum value, which reduce the bearing film rigidity and affect the machine tool precision. This paper proposed a controllable hydrostatic thrust bearing, which combined the constant flow chambers and the controllable flow chambers. The chamber flow can be adjusted automatically according to the load, the cutting force, and the thermal results of thrust bearing. The controllable chamber flow was adjusted by the electro-hydraulic servo variable mechanism. The oil film thickness error was measured in real time to maintain the most optimum film thickness. The models of controllable chamber flow and servo variable mechanism were established, and the model identification experiments for servo variable mechanism were carried on. The hardware-in-loop simulation results show that the controllable bearings assure the stability and rapidity of system, compensate effectively the effect of load parameter on oil film thickness, and improve the position tracking performance, and validate the creditability of the identification model.

To enhance the clinical doctors' cognizance of atypical spinal dural arteriovenous fistulae (SDAVFs) associated with perimedullary anteriovenous fistulae (PMAVFs).The clinical imaging and surgical therapy of 3 patients with PMAVFs were analyzed retrospectively.The clinical presentations of the 3 patients were not significantly different from those of typical SDAVFs. They were verified by repeated spinal angiography that the anterior spinal artery (ASA) is supplied to the drainage-vein. The 3 patients were treated surgically. First two operations were performed to eliminate the supply of ASA and dural branch, then the supply of the dural branch was amputated, and finally both the ASA and dural branch supplies were excised successfully. Clinical symptoms of the 3 patients were improved after treatment.It is necessary to perform thorough spinal angiography in patients with SDAVFs to exclude another fistula. The key point in the treatment of such patients is successfully to terminate both the spinal feeder and dural branch feeder.