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Polycrystalline diamond compact (PDC) drill bit often performs with low ROP, short service life and poor stability under complicated and difficult to drill formations. Therefore, a vertical wheel PDC bit is proposed, which is a new drill bit technology applying an integrated unit combining the tooth wheel and the rotary shaft thereof. Besides, the experiments on motion and mechanical characteristics of the vertical wheel under the conditions of tooth shape and number of teeth, normal deflection angle of the wheel, and different cutting depth were carried out using variable parameter experimental device, and the movement, force law, and crushing specific work of vertical wheel under different experimental conditions were obtained. The comparative experiments of PDC cutting rock breaking under the conditions of parallel cutting of PDC unit and pre-damage of the wheel were also carried out, and the cutting load of PDC teeth under pre-damage conditions is between 38.72% and 70.95% lower than that of parallel cutting was obtained. Finally, a comparative experiment of indoor drilling between vertical wheel PDC bit and conventional PDC bit was carried out. Results show than when drilling in gravel rock, under the same WOB, the torque response of vertical wheel PDC bit is equivalent to that of the PDC bit, while the ROP of vertical wheel PDC bit is 22.94%e53.33% higher than that of conventional PDC bit, and the threedimensional acceleration of the vertical wheel PDC bit is 19.17%e76.23% of that of the PDC bit. The experimental results contribute to a better understanding of vertical wheels and provide technical support for their use in PDC bits. [ABSTRACT FROM AUTHOR]

A combined unit, which has the ability to measure the current and emittance of the high intensity direct current (DC) ion beam, is developed at Peking University (PKU). It is a multi-slit single-wire (MSSW)-type beam emittance meter combined with a water-cooled Faraday Cup, named high intensity beam emittance measurement unit-6 (HIBEMU-6). It takes about 15 seconds to complete one measurement of the beam current and its emittance. The emittance of a 50-mA@50-kV DC proton beam is measured. [ABSTRACT FROM AUTHOR]

Optical emission spectroscopy (OES), as a simple in situ method without disturbing the plasma, has been performed for the plasma diagnosis of a 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source at Peking University (PKU). A spectrum measurement platform has been set up with the quartz-chamber electron cyclotron resonance (ECR) ion source [Patent Number: ZL 201110026605.4] and experiments were carried out recently. The electron temperature and electron density inside the ECR plasma chamber have been measured with the method of line intensity ratio of noble gas. Hydrogen plasma processes inside the discharge chamber are discussed based on the diagnostic results. What is more, the superiority of the method of line intensity ratio of noble gas is indicated with a comparison to line intensity ratio of hydrogen. Details will be presented in this paper. [ABSTRACT FROM AUTHOR]

Background: Encephalitis with antibodies against N-methyl D-aspartate receptor (NMDAR) is recognized as a group of antibody-mediated neuropsychiatric syndromes, which occurs with and without a tumor association. Neoplasm may contribute to the pathogenesis of Anti-NMDAR encephalitis in tumor-positive patients. However, the underlying causes in tumor-negative patients are largely unknown. This is the first report, of which we are aware, of two cases of anti-NMDAR encephalitis after the resection of melanocytic nevus.Case Presentation: We describe 2 female patients in their 20s confirmed with anti-NMDAR encephalitis. They shared two points in common: About several weeks (2 weeks and 5 weeks respectively) before the initial symptom, both of them underwent a resection of melanocytic nevi; the screening tests for an ovarian teratoma and other tumors were all negative. A 25 year-old woman presented with seizure, psychiatric symptoms and behavioral change for 2 weeks. Electroencephalogram indicated electrographic seizures. Anti-NMDAR antibodies were all positive in the cerebrospinal fluid and serum. Her symptoms relieved gradually after the treatment with steroids and mycophenolate mofetil. Another patient admitted to our hospital with psychosis, behavioral change and complex partial seizure over a period of 5 months. Electroencephalogram demonstrated generalized slow activities. High titres of anti-NMDAR antibodies were both detected in the cerebrospinal fluid and serum. She responded well to the first-line immunotherapy and got substantial recovery.Conclusion: Our cases provided an observational link between anti-NMDAR encephalitis and resection of nevi. We postulate that the exposure of certain antigen on nevus cell caused by nevi excision, which might be NMDA receptor or other mimic cross-reactive antigens, may trigger an autoimmune response resulting in encephalitis. This suggested a potential site of antigen exposure triggering the immune response in non-tumor associated anti-NMDAR encephalitis, which may lend support to elucidating the underlying immunopathological mechanisms. Further studies are expected for investigating the expression of NMDA receptor on nevus cell and evaluating the validity of this hypothesis. [ABSTRACT FROM AUTHOR]

A miniaturized 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source, which has the ability of producing a tens-mA H+ beam, has been built and tested at Peking University (PKU). Its plasma chamber dimension is Φ30 mm × 40 mm and the whole size of the ion source is Φ180 mm × 130 mm. This source has a unique structure with the whole source body embedded into the extraction system. It can be operated in both continuous wave (CW) mode and pulse mode. In the CW mode, more than 20 mA hydrogen ion beam at 40 kV can be obtained with the microwave power of 180 W and about 1 mA hydrogen ion beam is produced with a microwave power of 10 W. In the pulse mode, more than 50 mA hydrogen ion beam with a duty factor of 10% can be extracted when the peak microwave power is 1800 W. [ABSTRACT FROM AUTHOR]

High current hydrogen molecular ion beam is obtained with a specially designed stainless steel liner permanent magnet 2.45-GHz electron–cyclotron resonance (ECR) ion source (PMECR II) at Peking University (PKU). To further understand the physics of the hydrogen generation process inside a plasma chamber, theoretical and experimental investigations on the liner material of the plasma chamber in different running conditions are carried out. Several kinds of materials, stainless steel (SS), tantalum (Ta), quartz, and aluminum (Al) are selected in our study. Experimental results show that stainless steel and tantalum are much better than others in generation. During the experiment, an increasing trend in fraction is observed with stainless steel liner after O2 discharge inside the ion source. Surface analyses show that the roughness change on the surface after O2 discharge may be responsible for this phenomenon. After these studies, the pure current of ions can reach 42.3 mA with a fraction of 52.9%. More details are presented in this paper. [ABSTRACT FROM AUTHOR]

Background: Morvan syndrome is a rare disorder characterized by the combination of peripheral nerve hyperexcitability, encephalopathy and dysautonomia with marked insomnia. It was reported to have association to antibodies to voltage-gated potassium channels including contactin associated protein-like 2 antibodies (CASPR2-Ab) and leucine-rich glioma inactivated protein 1 antibodies (LGI1-Ab). LGI1-Ab was reported to associate with seizures, amnesia, confusion, hyponatraemia and a good prognosis, while CASPR2-Ab with peripheral presentations, probable risk for tumor and a poor prognosis. The vast majority of Morvan syndrome patients were male, with normal magnetic resonance imaging of the brain.Case Presentation: We report a female case presenting with a combination of bilateral leg pain, widespread myokymia, memory disturbance, seizure, hyperhidrosis and insomnia. She had antibodies targeting CASPR2 and LGI1, tested by the indirect immunofluorescence test, which demonstrated the diagnosis of typical Morvan syndrome as well as classical limbic encephalitis. Cranial MRI revealed bilateral hyper-intensity of the medial temporal lobe, insular lobe and basal ganglia on T2/FLAIR and DWI sequence. As the treatment carried on, her serum LGI1-Ab disappeared and her memory loss, seizure and confusion quickly relieved. But her peripheral presentations did not relieve until serum CASPR2-Ab turned negative. Intravenous immunoglobulin treatment showed limited efficacy while she achieved almost complete remission with corticosteroids therapy.Conclusions: This case provides a rare female resource of Morvan syndrome, which is the first patient with both CASPR2-Ab and LGI1-Ab positive Morvan syndrome in China and one of the few female patients with Morvan syndrome reported so far. Through the detailed analysis of her clinical course, the diverse and overlapping clinical phenotype of CASPR2-Ab and LGI1-Ab in patients with Morvan syndrome was obvious and interesting. [ABSTRACT FROM AUTHOR]

The stability and reliability of an ion source and its beam availability are extremely significant for any accelerator, especially for those high current long term CW operation ones like ADS. Although the first high quality 306-hours continuous wave (CW) operating curve at 50 mA@35 keV has been successfully obtained with a standard compact 2.45 GHz ECR ion source at Peking University (PKU), but the uncertainties that caused beam trips before are unacceptable during an accelerator real operation and should be eliminated. Meanwhile, no permission will be given when the beam power is upgraded from 50 mA@35 keV to 50 mA@50 keV. To improve the PKU CW proton source quality, several upgrades were done recently. After those improvements, a new long term CW proton beam experiment at 50 mA@50 keV was carried out in June 2016. The total running time is 300.5 hours, including near 6 hours ion source preparation and 294 hours non-disturb continuous operation. Within the continuous 13 days operation, no beam-off happened, no spark was observed, no beam drop appeared, no interrupting action was needed, and only a few beam fluctuations caused by the air conditional failure occurred. Beam availability and reliability within the 294 hours is 100%. The root-mean-square (RMS) emittance of this 50 mA@50 keV CW proton beam is about 0.186 π.mm.mrad. A careful inspection of the ion source was done after this long term operation and no obvious damage was found. The restart experimental results obtained after the ion source inspection prove the high repeatability of PKU PMECRIS. In addition, a 130-mA H+ beam was obtained at 50 kV with duty factor of 10% (100 Hz/1 ms) with this source. Details will be presented in this paper. [ABSTRACT FROM AUTHOR]

Background Some recent studies suggest that some imaging-negative temporal lobe epilepsy (TLE) had significant amygdala enlargement (AE). Contradictory data were also reported in previous studies regarding the association between AE and TLE. The present study was to investigate the clinical characters of a group of TLE with AE and compare the amygdala volume of the same patient before and after antiepileptic drugs treatment by a larger sample size. Methods This study recruited 33 mesial TLE patients with AE and 35 healthy volunteers. The clinical history, seizure semiology, electroencephalogram (EEG), fluorodeoxyglucose-positron emission tomography (FDG-PET) and amygdala volume were investigated. The amygdala volume were compared between ipsilateral and contralateral sides, TLE patients and 35 healthy controls, and patients at first and follow-up visit by 3.0 T MRI. Results Average seizure onset age was 42.0 years (SD 14.3). All patients had complex partial seizures, fourteen had occasional generalized tonic-clonic seizures which often happened during sleep. Ninety percent patients suffered from anxiety or depression. Thirty percent patients had memory decline. Interictal epileptiform discharges appeared predominantly in the anterior or inferior temporal area ipsilateral to AE. Interictal FDG-PET showed regional glucose hypometabolism in the ipsilateral temporal lobe. No hippocampal sclerosis (HS) was suspected in all patients. 22 patients demonstrated good seizure control and significantly reduced volume of the enlarged amygdala after treatment (P < 0.01). The other 11 patients showed initial response to treatment, followed by a gradual increase in seizure frequency over time, and no volume change of the enlarged amygdala after treatment. Conclusions TLE with AE probably represents a distinct nosological and probably less homogeneous syndrome which is most likely a subtype of TLE without ipsilateral HS. The chronic and long lasting inflammatory processes or focal cortical dysplasia could lead to amygdala enlargement possibly. [ABSTRACT FROM AUTHOR]

The hematite nanorods and magnetite nanoparticles were synthesized via direct thermolysis of an iron-based metal-organic framework materials MIL-100(Fe) (MIL: Materials of Institut Lavoisier) for the first time and used as absorbents for the removal of As(V). The prepared materials were characterized by XRD, SEM, TEM and BET. It was found that calcination temperature and calcination atmosphere affected the pore sizes and types of the obtained materials, and then further influenced the removal of As(V). At pH 3, the As(V) adsorption capacities of obtained Fe3O4 and α-Fe2O3 calcined at 350 °C, 550 °C, 750 °C were 80.5 mg g-1, 94.9 mg g-1, 74.1 mg g-1 and 70.5 mg g-1, respectively. This approach may provide reference for the synthesis of other metal oxide nanoparticles. [ABSTRACT FROM AUTHOR]

A practical 2.45-GHz microwave-driven Cs-free H− source was improved based on the experimental H− source at Peking University (PKU). Several structural improvements were implemented to meet the practical requirements of Xi’an Proton Application Facility (XiPaf). Firstly, the plasma chamber size was optimized to enhance the plasma intensity and stability. Secondly, the filter magnetic field and electron deflecting magnetic field were enhanced to reduce co-extracted electrons. Thirdly, a new two-electrode extraction system with farther electrode gap and enhanced water cooling ability to diminish spark and sputter during beam extraction was applied. At last, the direct H− current measuring method was adopted by the arrangement of a new pair of bending magnets before Faraday cup (FC) to remove residual electrons. With these improvements, electron cyclotron resonance (ECR) magnetic field optimization experiments and operation parameter variation experiments were carried out on the H− ion source and a maximum 8.5-mA pure H− beam was extracted at 50 kV with the time structure of 100 Hz/0.3 ms. The root-mean-square (RMS) emittance of the beam is 0.25π⋅mm⋅mrad. This improved H− source and extraction system were maintenance-free for more than 200 hours in operation. [ABSTRACT FROM AUTHOR]