In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence.

Accurate control of the polarization states of laser light is important in precision measurement experiments. In experiments involving the use of a vacuum environment, the stress-induced birefringence effect of the vacuum windows will affect the polarization states of laser light inside the vacuum system, and it is very difficult to measure and optimize the polarization states of the laser light in situ. The purpose of this protocol is to demonstrate how to optimize the polarization states of the laser light based on the fluorescence of ions in the vacuum system, and how to calculate the birefringence of vacuum windows based on azimuthal angles of external wave plates with Mueller matrix. The fluorescence of 25Mg+ ions induced by laser light that is resonant with the transition of |32P3/2,F = 4, mF = 4 â†’ |32S1/2,F = 3, mF = 3 is sensitive to the polarization state of the laser light, and maximum fluorescence will be observed with pure circularly polarized light. A combination of half-wave plate (HWP) and quarter-wave plate (QWP) can achieve arbitrary phase retardation and is used for compensating the birefringence of the vacuum window. In this experiment, the polarization state of the laser light is optimized based on the fluorescence of 25Mg+ ion with a pair of HWP and QWP outside the vacuum chamber. By adjusting the azimuthal angles of the HWP and QWP to obtain maximum ion fluorescence, one can obtain a pure circularly polarized light inside the vacuum chamber. With the information on the azimuthal angles of the external HWP and QWP, the birefringence of the vacuum window can be determined.

A simple method for in situ measurement of vacuum window birefringence.

We present a simple method to measure the degrees of circular polarization (DoCP) of laser light inside a vacuum chamber and the birefringence of a vacuum window by detecting the fluorescence emitted by Doppler cooled ions in an ion trap. Imperfect laser polarization will cause ions to be pumped to the dark state which will decrease the fluorescence rates of the ions. With a simulation based on the rate equations of the relevant energy levels of 25Mg+ ions, we find that the fluorescence rate is sensitive to the DoCP of the laser. Based on the simulation result, we present a new method to optimize the DoCP of the laser inside the vacuum chamber by adjusting fast axis azimuthal angles of a half-wave plate and a quarter-wave plate outside the vacuum chamber. The laser light is optimized to be circularly polarized with an uncertainty of the DoCP of 7.8 × 10-5. With the obtained polarization information on both sides of the vacuum window and treating the vacuum window as an unknown wave plate, the phase delay and the fast axis azimuthal angle of the vacuum window can be determined in the form of Mueller matrix. The phase delay is determined to be 197.60(39)°, and the fast axis azimuthal angle is determined to be 104.00(5)°.

Image evaluation of suprazygomatic masticator space lesions.

In order to understand lesions involving the suprazygomatic masticator space (SZMS) demonstrated on computered tomography (CT) or magnetic resonance (MR) images, we collected 45 cases of lesions in SZMS. There were hematomas in 26 cases, tumors in 16 cases, and abscesses in 3 cases. The location of these lesions in compartments of the SZMS and adjacent structures was analyzed. Most commonly hematoma was found in the deep loose connective tissue (80.8%), followed by the superficial dense connective tissue (61.5%). Only 2 SZMS hematoma involved the superficial fat pad. Five patients had air accumulation in the SZMS, and all were in the deep fat pad and with maxillary sinus fracture. Of the sixteen cases which were tumors, 12 were extended from adjacent structures, and four were primary tumor. In cases of tumor, compartments of SZMS involved most frequently were temporal muscles (15 of 16 cases), followed by deep fat pad (8 of 16 cases). The connective tissue layer of SZMS is a communication pathway for superficial spread of infection, hematoma, or tumor invasion to or from the scalp and face. Compartments of deep fat pad and temporal muscle are also pathways for the spread of disease to or from the face, intracranium and orbit. The primary tumors in infratemporal fossa and SZMS are rare. Malignant tumors in SZMS usually come from surrounding spaces.

A modified model of helical resonator with predictable loaded resonant frequency and Q-factor.

High voltage radio frequency (RF) supply is a critical part in an ion trapping system. The RF supply should have high Q-factor and relatively high driving frequency. A frequently used RF supply for an ion trap system is a helical resonator. In certain applications, it is advantageous to have a predictable resonant frequency and Q-factor when the helical resonator is connected to a capacitive load. We develop a model to describe the behavior of a helical resonator with capacitive load. With this model, we can correctly predict the loaded resonant frequency and the loaded Q-factor. To test our prediction, we construct a helical resonator, and measure its resonant frequencies and Q-factors under different capacitive loads. The experimental results agree with our prediction.

A long-term frequency stabilized deep ultraviolet laser for Mg+ ions trapping experiments.

As many precision laser spectroscopy experiments require frequency stabilized lasers, development of long-term stabilized lasers is of great interest. In this work, we report long-term frequency stabilization of a 280 nm deep ultraviolet laser to a high precision wavemeter with digital servo control such that the long-term drift of the laser frequency was greatly reduced. Long-term laser frequency drift was measured with a fiber frequency comb system over 8 h. After locking, the maximum drift rate of the 280 nm laser was lowered from 576 MHz/h to 6.4 MHz/h. With proper environment control of the wavemeter, the maximum drift rate of the 280 nm laser was further lowered to less than 480 kHz/h. The locked laser system was successfully used in a Mg(+) ions trapping experiment, which was also discussed in this work.

Preventive vertebroplasty for adjacent vertebral bodies: a good solution to reduce adjacent vertebral fracture after percutaneous vertebroplasty.

BACKGROUND AND PURPOSE: Adjacent VCF frequently occurs after percutaneous vertebroplasty. Our aim was to evaluate PrVP in the prevention of PVNO-adjacent VCF. MATERIALS AND METHODS: Radiographs of 68 patients who initially presented with a single-level unhealed fracture and underwent vertebroplasty were retrospectively reviewed for the occurrence of PVNO fracture. Patients in the nonpreventive group (n = 33) underwent TVP only for a vertebra with an unhealed fracture. The preventive group (n = 35) underwent PrVP combined with TVP. We injected bone cement into the caudal part of the superior adjacent vertebra and the cephalic part of the inferior adjacent vertebra to perform PrVP. RESULTS: The incidences of PVNO fracture in adjacent vertebra next to a vertebra cemented at the patient's first vertebroplasty (within 6 months: 24% versus 3%, P = .012; within 1 year: 30% versus 3%, P = .006; >4 years: 39% versus 3%, P = .006) markedly decreased in the preventive group compared with the nonpreventive group. PVNO fracture was found in 26% of vertebrae adjacent to the first TVP level in the nonpreventive group and in 2% of vertebrae adjacent to a PrVP level in the preventive group after inclusion of all PrVP procedures. Approximately 33% of patients in the nonpreventive group underwent repeat vertebroplasty, mainly due to adjacent fractures. Only 3% of patients in the preventive group underwent repeated procedures. None of the vertebrae cemented for PrVP or TVP developed PVNO refracture. CONCLUSIONS: Preventive vertebroplasty for the adjacent vertebra combined with TVP for the fractured vertebra is effective in the prevention of propagation of PVNO adjacent fractures, thus reducing the necessity of multiple repeat vertebroplasty procedures.

[Evaluation of speech aid's function with air flow pressure techniques]

OBJECTIVE:To evaluated of speech aid's function with air flow pressure techniques. METHODS: The study group contained 12 patients with cleft palate,submucous cleft palate and congenital velopharyngeal insufficiency who had been found to have VPI(velopharyngeal insufficiciency) and hypernasal speech and were scheduled for speech aid. RESULTS: It was confirmed that study was to assess the relationship between oral-nasal resonance with and without the speech aid. CONCLUSION: The speech aid be able to improve the velopharyngeal function in some VPI patients,also it is useful clinical results for the speech therapiist.

[Cephalometric analysis of maxillary development in adult unoperated cleft palate patients]

OBJECTIVE: Analysis of maxillary development in adult unoperated cleft palate patients.METHODS:Lateral cephalometric radiographs of 37 case of adult unoperated cleft palate (UCP) patients were analyzed with computerized aided image system, 20 normal adults were as a control group.RESULTS: Showed that maxillary anteroposterior distance of UCP group is shorter than normal control group (P<0.05) and there is no significant difference on superoinferior distance of jaw between the UCY group and normal control group (P>0.05).CONCLUSION:The cleft palate intrinsic deformities can interfere maxillarv normal development.

[A study on speech training methods for patients following cleft palate repair]

OBJECTIVE:This study is to improve speech articulations of patients following cleft palate repair. METHODS: 20 cases were treated with systemic speech trainning. The methods included testing speech articulations of pre-and post-training blowing and systemic speech training whose program was consonant (first step), syllable (second), word (third), sentence (forth), and (fifth). RESULTS: It is showed that their articulations improved from 48.1% to 97.1% on average,and,the improvement in speech was highly significant statistically(P<0.0001).The younger the patient was,the shorter the training circle was. CONCLUSION: Speech training can correct habit of compensatory pathologic articulation and improve articluation of patient following cleft palate repair.

[The normal people's parameters of the velopharyngeal incompetence(VPI) by cephalometric analysis]

OBJECTIVE:To estimate velopharyngeal incompetence(VPI)in patients with cleft lip and palate,we seek for the normal people's parameters of VPI. METHODS:Studying on 222 normal people with VPI by cephalometric analysis,the parameters of the normal people have been set up.RESULTS: There was remarkable correlationship between the rate of velopharyngeal sagital restriction by cephalometric analysis and the rate of VPI by nasopharyngeal endoscope.CONCLUSION:Cephalometric analysis is useful to estimate the function of velopharyngeal closure and mobility of the soft palate.

[A comparative study of velopharyngeal function after palatoplasty with different age group]

That the most suitable age of palatoplasty is still an argumentative question.The final purpose of palatoplasty is to obtain the satisfactory effectiveness is to obtain the satisfactory effectiveness of phonetic distinctness.So,early palatoplasty is suported by more more experts and patient's parents.This study detected 60 cases velopharyngeal function after traditional palatoplasty with two flaps,adopting nasopharyngeal fiberscope and detective system of image processing and quantitative analysis of velopharyngeal function,for long term evaluation of traditional palatoplasty with different operative success iin early palatoplasty group (less than 3 years old) was 80.0% while that in later palatoplasty group (more than 6 years old) was 53.3%.From other aspects of types of velopharyngeal competence,mobility of soft palate and rate of velopharyngeal coronary contraction,the author described advantages of early palatoplasty.

[Quantitative study of velopharyngeal function post-palatoplasty]

The computer of nasopharyngeal fiberscope(NPF) for quantitative analysis was carried out to assess the palate articulation of 43 subjects,and normal articulation of 60 subjects.The rest,/a/,/s/and /m/ articulation of NPF pictures were calculated for veloparyngreal function via computer.

[Cephalometric analysis in the patients of TMJ ankylosis with OSAS: Skeletal morphology]

By cephalometric analysis of 18 normal men and 12 men who got TMJ ankylosis with obstructive sleep apnea syndrome(OSAS),the authors reported that there were cephalometric characteristics in the patients:the craniomaxillofacial bones displacement posteriorly and superiorly,and demonstrated that it is key to advance the patients' jaws and enlarge the upper airway space.

[The pre-and-postoperative cephalometric evaluation on the patients of TMJ ankylosis with OSAS]

After taken the comparative studies on the cephalometric analysis of the patients of TMJ ankyolsis with OSAS pre-and-post operation,the authors demonstrated the method combining TMJ reconstruction and orthognathic surgery is responsible to the patients.

[Cephalometric analysis in the patients of TMJ ankylosis with OSAS: Soft tissue morphology]

By cephalometric analysis of 18 normal men and 12 men who got TMJ ankylosis with obstructive sleep apnea syndrome(OSAS),the authors reported that there were cephalometric characteristics in the patients:the posterior airway space(PAS) decreased(P<0.001),and the rate of (TA+SPA)/OPA remarkably increased(P<0.001),so the two parameters are significant for the diagnosis and treatment of the patients.

[The pre-postoperative polysomnographic evaluation on the patients of TMJ ankylosis with OSAS]

Passing by the comparative studies on the polysomnogram of the patients of TMJ ankylosis with OSAS pre-and-postoperation,the result showed the patients' AI (Apnea Index;AI) has been decreasing,SaO(2) during sleep get to rise,and the method combining TMJ reconstruction and orthognathic surgery is effective to the patients.

[Primary study on speech training of palatalized misarticulation].

OBJECTIVE: In this paper, differences in 10 palatalized misarticulation patients between pre-and post-speech training were reported to discuss the training methods of palatalized misarticulation. METHODS: 10 palatalized misarticulation patients (6 male, 4 female) with the age of 4-14 years were included in the study. All the patients had undergone systematic speech therapy,and their speech intelligibilities were analyzed. RESULTS: All patients' speech intelligibilities after training were significantly higher than those before training. /s/, /z/, /c/, /d/, /t/, /zh/, /ch/, /sh/, /j/, /q/ and /x/ were often involved. CONCLUSION: Palatalized misarticulation was caused by abnormal palato-lingual contact which leads to decreasement of speech intelligibility. Speech training is the only method to correct the wrong articulation position and articulation method. The key of training methods for palatalized misarticulation is to plane the dorsum and release the tongue's retroflex.