Search

Using a dusty plasma ratchet, one can realize the rectification of charged dust particle in a plasma. To obtain the ratchet potential dominating the rectification, here we perform quantitative simulations based on a two-dimensional fluid model of capacitively coupled plasma. Plasma parameters are firstly calculated in two typical cross sections of the dusty plasma ratchet which cut vertically the saw channel at different azimuthal positions. The balance positions of charged dust particle in the two cross sections then can be found exactly. The electric potentials at the two balance positions have different values. Using interpolation in term of a double-sine function from previous experimental measurement, an asymmetrical ratchet potential along the saw channel is finally obtained. The asymmetrical orientation of the ratchet potential depends on discharge conditions. Quantitative simulations further reproduce our previous experimental phenomena such as the rectification of dust particle in the dusty plasma ratchet.

In this article, a novel cryotherapy approach using a uniform, controlled, and consistent in vivo application of liquid nitrogen (LN2) spray as a Metered Cryospray™ (MCS) process is described. Although MCS may be used for many potential clinical applications, this paper focuses on the development that led to the controlled and consistent delivery of radial LN2 cryogen spray in order to generate a uniform circumferential effect and how the amount of MCS can be adapted to specifically ablate targeted diseases within a patient’s lumen such as an airway or esophagus., Video abstract

Platelets primarily participate in hemostasis and antimicrobial host defense. The present study aimed to investigate the effects of leucine-rich repeat flightless-interacting protein-1 (LRRFIP1) on platelet agglutination. The bacterial strain of LRRFIP1 was used to synthesize the recombinant protein and a mouse model of LRRFIP1 gene knockout was established. Platelets were isolated from the mice and divided into the different trial groups according to their treatment with collagen, thrombin receptor SFLLRN, anti-wild-type (w)LRRFIP1monoclonal antibodies and the model of LRRFIP1 gene knockout. The platelets were prepared and platelet agglutination was examined using platelet aggregation apparatus. The active αIIbβ3 integrin was examined by flow cytometry. The results revealed that the combined wLRRFIP1 protein was successfully expressed. wLRRFIP1 treatment significantly triggered platelet agglutination of collagen, thrombin and monoclonal antibody treated platelets. wLRRFIP1 knockout significantly decreased αIIbβ3 levels compared with the wild-type. Platelet agglutination was also significantly inhibited in the LRRFIP1−/−mouse model compared with the wild-type. LRRFIP1 knockout significantly decreased the αIIbβ3 levels in platelets undergoing convulxin treatment. In conclusion, LRRFIP1 treatment triggered platelet agglutination and LRRFIP1 gene knockout inhibited platelet agglutination. In addition, LRRFIP1 gene knockout significantly decreased the levels of αIIbβ3. This suggests that LRRFIP1 my be applied to patients in a clinical setting to trigger platelet agglutination in inflammatory diseases and atherothrombotic diseases.

A kinetic model of atmospheric streamer discharges on conductors with surface protrusion is first presented. The formations of streamer discharges in air on both the smooth conductors and rough conductors with different surface protrusions have been studied by using two-dimensional particle-in-cell simulations complemented by Monte Carlo collisions (PIC-MCC). The evolutions of electric fields, plasma densities as well as the propagation velocity of the streamers are demonstrated. Moreover, the influences of the sizes of surface protrusions on development of the discharge have been investigated. It is shown that, compared with the discharge on a smooth conductor, the streamer discharge is greatly favored by the protrusion, whose maximum electric field, electron density and propagation velocity are increased. Under the same discharge conditions, the discharges with medium sizes of the protrusions are the strongest, rather than those with protrusions of small size or big size. Our results reveal the underlying physics governing the discharge and have promising applications in high voltage (HV) transmission engineering.

Research on informational masking for nonspeech stimuli has focused on the effects of spectral uncertainty in the masker. In this letter, results are presented from some preliminary probe experiments in which the spectrum of the masker is held fixed but the spatial properties of the masker are randomized. In addition, in some tests, the overall level of the stimulus is randomized. These experiments differ from previous experiments that have measured the effect of spatial uncertainty on masking in that the only attributes (aside from level) that distinguish the target from the masker are the spatial attributes; in all of the tests, the target and masker were statistically identical, statistically independent, narrowband noise signals. In general, the results indicate that detection performance is degraded by spatial uncertainty in the masker but that compared both to the effects of spectral uncertainty and to the effects of overall-level uncertainty, the effects of spatial uncertainty are relatively small.

Objective: To summarize the technique and surgical outcome for total resection of lower sacral tumor. Methods: This retrospective study included 12 cases of total resection of lower sacral tumor (involving S3 and the below) from January 2010 to February 2013. Seven patients underwent en bloc resection and five cases accepted intralesional curettage. We used extraperitoneal approach to ligature the bilateral internal iliac artery, separated the tumor, and used transverse incision to separate the sacrum from surrounding ligaments and muscles. We then separated the sacrum to S2-S3 junction and ligatured the dural sac, cut off the sacrum at the S2-S3 junction, and remove the tumor out of the envelope. The other five patients underwent posterior surgery, which directly revealed lesions. Curettes were used under direct vision to scrape the tumor tissue. Results: All patients underwent the operation successfully without perioperative death or serious complication. The blood loss ranged from 300-650 mL (460 mL in average) in en bloc resection group. The blood loss ranged from 350-2800 mL (1595 mL in average) in curettage group. One case of transient enteroplegia and one case of transient gatism were respectively reported in en bloc resection group and one case of chronic pain in sacral was reported in curettage group. The postoperative pathological results revealed that there were 4 chordomas, 2 giant cell tumor and 1 metastatic tumor in en bloc resection group. All patients were followed up for 4-36 months (13.6 in average). At the final follow-up there was no recurrence reported. Two cases of local recurrence (40%) in curettage group were reported. Conclusion: The surgery combined with anterior-posterior approach helped remove the lower sacral tumor totally, with uncomplicated surgical operations and obviously reduced recurrence rate. The recurrence rate was significantly reduced using curettage method.

Background: The most common treatment for old calcaneal fractures accompanied by subtalar joint injury is the use of subtalar in situ arthrodesis and subtalar distraction bone-block arthrodesis or osteotomy. This article describes the introduction of a novel surgical treatment, gradual subtalar distraction with external fixation and restoration of the calcaneal height, and presents an assessment of its efficacy. Methods: The protruding lateral calcaneus and the articular surfaces and subchondral bone of the posterior facet of the subtalar joint were surgically removed. An external fixator, attached with 2 pins in the subcutaneous tibia and 2 pins in the posterolateral calcaneus, was used to fix the subtalar joint for 7 to 10 days followed by gradual subtalar distraction at 1 mm/d. The lengthening procedure was stopped when the calcaneal height was restored according to radiography. The external fixator was removed after bone fusion. Seven cases of old calcaneal fractures accompanied by severe subtalar joint injury (8 feet) were treated using this method. Average follow-up was 14.3 months (range, 7-36 months). Results: In all 7 cases (1 case of both feet), the postoperative wound healed primarily. The calcaneal heights of all 8 feet were partially restored. Subtalar joint bone fusion was completed within 4 to 6 months after the operation. The average preoperative American Orthopedic Foot & Ankle Society (AOFAS) hindfoot score was 25.3, and the average postoperative AOFAS score was 76.3. Conclusion: Subtalar distraction osteogenesis with external fixation was a novel and effective method for the treatment of old calcaneal fractures accompanied by severe subtalar joint injury in this small group of patients. Level of Evidence: Level IV, retrospective case series.

The variations of width and shift of Ar I (2P2 --1S5) spectral line with discharge parameters were studied in a slot microplasma. In order to measure the wavelength shift, the Ar I (2P2 --1S5) spectral line emitted from argon discharge at pressure of 10 Pa was used as a reference line. With the gas pressure increasing in the range of 1 x 10(4) - 6 x 10(4) Pa, the width and shift of Ar I (2P2 --1S5) spectral line were measured in argon (99.92%)/air discharge. It was found that both the width and the shift of Ar I (2P2 --1S5) spectral line increase linearly with the increase in gas pressure, indicating that the electron density increases with the increase in gas pressure. In addition, the width and the shift of Ar I (2P2 --1S5) spectral line at gas gap width of 100 and 300 microm were measured for comparison. It was found that both increase with the increase in gas gap width, which indicates that the electron density in the slot microplasma increases with the increase in gas gap width.

The electron energy in the transition from streamer discharge to glow-like discharge in dielectric barrier discharge in air was investigated by using emission spectra. The vibrational temperature was measured with the N2 second positive band (C3II(u) --B3II(g)) of the emission spectrum. The average electron energy was investigated from the relative intensity of the nitrogen molecular ion line at 391.4 nm and the nitrogen molecular line at 337.1 nm. It was found that the vibrational temperature and the relative intensity of nitrogen molecular ion line at 391.4 nm increased abruptly in the transition from streamer discharge to glow-like discharge. It was also found that the pressure for the transition pressure from streamer discharge to glow-like discharge changed with different gap distances, but the product of the transition pressure and gas gap width remained constant.

The electron density in a subatmospheric dielectric barrier discharge by using argon spectral line shape is measured for the first time. With the gas pressure increasing in the range of 1×104 Pa–6×104 Pa, the line profiles of argon 696.54 nm are measured. An asymmetrical deconvolution procedure is applied to separate the Gaussian and Lorentzian profile from the measured spectral line. The gas temperature is estimated by using rotational temperature of N2+. By subtracting the van der Waals broadening and partial Lorentzian instrumental broadening from the Lorentzian broadening, the Stark broadening is obtained and used to estimate the electron density. It is found that the electron density in dielectric barrier discharge increases with the increase in gas pressure.

Reactive sputtering is a very useful technique for fabricating oxides and other compound thin films. Very recently, we developed a technique named multi-ion-beam reactive conputtering (MI-BRECS) for preparing multi-component metal oxide thin films. In order to promote the development of this technique, it is necessary to investigate the mechanisms of thin film growth of reactive cosputtering. Based on the well-known gas kinetics, we established a fundamental model of multi-ion beam, multi-target reactive cosputtering under stable sputtering circumstances, and obtained the relationships between both the deposition rate and composition of thin films and the controllable reactive cosputtering parameters. This model reveals the essential parameters that affect the composition of thin films and the methods for controlling the deposition rate and the composition of thin films can be obtained from the model.