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)°.

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.

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 primary study on the relationship between condyle position and anterior distraction for cross bite caused by cleft lip and palate].

OBJECTIVE: To evaluate the changes of the position of the mandibular condyle in cleft lip and palate patients with secondary bony cross-bite deformity after early orthodontic treatment with extraoral bow and facial mask. METHODS: The TMJ topograph 6 months before and after treatment was investigated in 8 patients. The width of the anterior,superior and posterior space of the TMJ was compared prior to and post treatment. RESULTS: The results showed that there was no significant difference in the width of the three spaces of the TMJ before and after treatment. CONCLUSION: The position of the mandibular condyle had no significant change after maxillary anterior distraction with extraoral bow and facial mask.

[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.

[Assessment of velopharyngeal function in normal speech by CT].

OBJECTIVE: To find an objective method to assess velopharyngeal function by CT. METHODS: Three dimensional conformation of the velopharyngeal orifice of 30 subjects with normal speech at rest and /i:/ position were observed and analyzed. The linear distance and area of velopharyngeal orifice were measured and analyzed statistically. RESULTS: The average minimal area of velopharyngeal orifice at/i:/ position was 11.92+/-11.73 mm(2). The physical RVPI was 4.03+/-4.03%. Coronary closure was the most common type of velopharyngeal contraction which accounted for 50%, semi-ring type being 30%, and ring type being 20%. No sagittal closure were seen in this study. There were 70% subjects whose position of velopharyngeal closure was at the level of the first cervical vertebra, 26.7% above the level and 3.3% below it. The arrange of velopharyngeal closure was 9-12 mm in 83.4% subjects, and 3-6mm in 16.6%. CONCLUSION: As a method of assessing velopharyngeal function, CT can not only observe the conformation of velopharyngeal orifice in three dimensions, but also quantitatively analyze the velopharyngeal function.

[Early face mask treatment for maxillary hyperplasia in patients with cleft lip and Palate]

OBJECTIVE: Early interfering orthodontics were used to treat maxillary hyperplasia by face mask and extra-oral bow technique in teenages.The position changes of maxilla after orthodontic treatment were evaluated.METHODS:The cephlometric variables before and after treatment were measured.Variables after treatment were compared with normal values in children with same ages,and changes of the maxillary position was determind.RESULTS:The position of the maxilla after orthopedics was significantly advanced (P<0.001),but there was still difference from normal values.CONCLUSION:In the peroid of mixed dentition of patients with cleft lip and palate,early orthodontics on maxillary hyperplasia could stimulate maxillary development and growth,remove or improve crossbite,extra-oral bow and face mask were efficient tools for this kind of patients.

[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.

[Presurgical infant orthopedics in complete bilateral cleft lip and palate reconstruction]

OBJECTIVE:This study want to effects on using intraoral-appliance treatment of complete bilateral left lip and Palate in clinic.METHODS:Using Lisson's method preliminary evaluated to effect of presurgical infant orthopedics complete bilateral cleft lip and palate.A sample of 4 cases of 18 weeks infant complete bilateral cleft lip and palate.2 of they are males, others are females.All of they had received presurgical infant orthopedics,Using intraoral appliance. comparison of before and after cast analysis.Evaluate anteiro posteior I, tranverse,oblique degree of the lateral segment, pretrusion premaxilla position change.RESULTS:Every patients after orthopedics treatment had retracted premaxilla come back,corrected of oblique of premaxilla,had lateral segments growth equally on both side,their inclination should be similar.CONCLUSION:Intraoral-appliance can successfully improved malarrangement maxilla of bilateral cleft lip and palate.

[Observation in vivo histological response induced by imlplanted domestic poly-DL-lactic acid plates]

OBJECTIVE:To analyze the histological response and biocompatibility to implanted domestic PDLLA plates in vivo METHODS:Bilateral artificial fractures were created in mandibular bodies in dog and internal fixed with domestic PDLLA plate,TM plate respectively;meanwhile,a domestic PDLLA plate was imlplanted in femur.The interfacial soft tissue around the plates were collected and performed histological study RESULTS:All the skin wound healed well without abscess and fistula formation. From 2 to 4 weeks after the operation,the inflmmatory granulomatous response around the intenal fixation PDLLA plates was more serious than that of the control,in which more macrophages,plasmocytes and less lymphocytes,mononuclear cells infiltrated CONCLUSION:Domestic PDLLA plate is an inert internal fixation material with good biocompatibility, which induced a non-speciflc foreign reaction

[Observation of the biodegradation of domestic poly-DL-lactic acid plates in vivo]

OBJECTIVE:To analyze the degradation and related factors of domestic poly-DL-lactic acid(PDLLA) plates in vivo. METHODS: The artifical transverse fractures in mandibular bodies of dogs were created and internal fixed with domestic PDLLA plates as experimental group,the implanted PDLLA plates in femurs as control.A certain time after the operation,the plates in fractured and implanted regions were collected and undertaken macroscopy and scanning electromicroscopy(SEM),meanwhile the fracture-healing status was evaluated. RESULTS: With time going on,the surface of domestic PDLLA plates y and density of micro-holes among poly-DL-lactic acid molecules in the PDLLA plates increased gradually.16-20 weeks Domestic PDLLA plates can be gradually biodegradation in vivo,in which it is correspondent with and accelerative the fracture-healing process.

[A comparison of the effects of 180kv X-ray radiation and cobalt-60 radiation on the jaws of the guinea pigs]

OBJECTIVE: Study of the effects of 180kv x-ray and cobalt-60 radiation on jaws and enhance the understanding of pathology of osteroradionecrosis of jaws(ORNJ).METHODS: 128 guinea pigs were grouped according to different irradiation sources and doses.Fractioned radiation from both sources was delivered in right mandible.The teeth extractions were conducted one week prior to radiation and 1,3,5 months after radiation respectively.Following radiation,the guinea pigs were examined by gross observation, x-ray film and histopathological examination at regular interval. RESULTS: Bone resorption occured within 1 month after irradiation as result of osteoblast inhibition and osteoclast activation.From 2 to 4 month afterwards,the number of osteocytes reduced and pyknosis, empty lacunae as well as obliteration of small vessels in periodontal membrane were commonly seen.The teeth extractions conducted at 3 months,5 months after radiation lead to ORNJ in 7 amimals (14.6%).CONCLUSION: 180kv x-ray radiation was far more damaging to jaws than cobalt-60 radiation.The dental extraction is an important factor inducint the development of ORNJ.

[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.