Large-tuning-range frequency stabilization of an ultraviolet laser by an open-loop piezoelectric ceramic controlled Fabry-Pérot cavity.

We demonstrate a laser frequency stabilization method with large tuning range to stabilize a UV laser by installing piezoelectric ceramic actuators into a Fabry-Pérot cavity with an ultra-low expansion spacer. To suppress piezoelectric drift, a two-layer symmetrical structure is adopted for the piezoelectric actuator, and a 14.7 GHz tuning range is achieved. The short-term drift of the piezoelectric ceramics caused by temperature and creep is eliminated, and the long-term drift is 0.268 MHz/h when the Fabry-Pérot cavity is sealed in a chamber without a vacuum environment. The long-term frequency drift is mainly caused by stress release and is eliminated by compensating the cavity voltage with an open loop. Without the need for an external reference or a vacuum environment, the laser frequency stabilization system is greatly simplified, and it can be extended to wavelengths ranging from ultraviolet to infrared. Owing to its simplicity, stability, and large tuning range, it is applicable in cold atom and trapped ion experiments.

[Influence of tension-free midurethral sling surgery on sexual function in women with stress urinary incontinence].

OBJECTIVE: To investigate the change of the female patients' sexual function after tension free vaginal tape (TVT) or transobturator suburethral tape (TVT-O) surgery for stress urinary incontinence (SUI). METHODS: Female sexual function index (FSFI) was sent to 66 female patients who underwent a TVT/TVT-O surgery at least 3 months after the operation, to a maximum of 5 years. All The patients were divided into two groups according to different surgical methods, different follow-up intervals (more than or less than 1 year) and whether there was concomitant coital incontinence (CCI) before the operation. The changes of FSFI scores before and after the operation were compared between the two groups by multiple covariances analysis. The total score was higher, and the sexual function was better. RESULTS: In the study, 60 patients answered the questionnaire, and 51 questionnaires were available. Before surgery, there were no significant difference between TVT and TVT-O groups in FSFI, age, body mass index (BMI). As to patients who had TVT/TVT-O surgery, when the influence of the postoperative period and symptoms accompanying intercourse were corrected, the two groups had no significant difference in difference of FSFI (dFSFI) scores after operation (F = 2.52, P = 0.119), and they had similar sexual function improvement ratio (40.0% vs. 44.4%, P > 0.05). But to the patients who had concomitant coital incontinence before the operations, the dFSFI scores was higher than patients who did not have concomitant coital incontinence (1.86 ± 1.95 vs. -0.09 ± 2.24, P < 0.05). CONCLUSION: TVT and TVT-O surgery have no significant difference in influence on sexual function in women between each other, but the patients who suffer from CCI before the surgery will have a better sexual function improvement.

[Analysis of related factors of premature delivery for the migrant population in local suburban Beijing areas].

OBJECTIVE: To study the health conditions of pregnant migrant women in some suburban areas of Beijing by comparing a variety of pathological, physiological and social factors and exploring the relevant factors associated with preterm birth so as to prevent effectively preterm birth. METHODS: A total of 279 cases of pregnancy in preterm birth at out hospital from January 2004 to December 2008 were reviewed. The date of maternal age, parity, prenatal examinations, history of vaginitis, history of chorioamnionitis, premature rupture of membranes, occupation, residing location and education status were recorded. And the relationship between them and preterm birth were analyzed by χ(2) test. RESULTS: The overall incidence of preterm birth was 5.34%. And the following factors had statistically significant differences with premature birth: chorioamnionitis, vaginitis, premature rupture of membranes, a lack of prenatal examinations, low education status, migrant population or maternal parity. However there was no statistical significance (P > 0.05) between preterm birth and other factors, such as occupation. CONCLUSION: The incidence of preterm birth is associated with a lack of prenatal examinations, low education status, chorioamnionitis, bacterial vaginitis and premature rupture of membranes. Therefore the migrant women in Beijing should receive targeted education programs during pregnancy. And reproductive tract inflammation should be properly treated.

[Extracorporeal membrane oxygenation for severe acute respiratory distress syndrome caused by novel 2009 influenza A (H1N1) virus].

OBJECTIVE: To summarize the clinical experiences and indications of extracorporeal membrane oxygenation (ECMO) for severe ARDS caused by novel 2009 influenza A (H1N1) virus. METHODS: All ECMO cases with severe ARDS associated with novel 2009 influenza A (H1N1) virus were analyzed in 5 intensive care units (ICUs) from 5 different hospitals in Beijing and Tianjin. A physician experienced in ECMO handling collected the relevant data, including general conditions pre and post-EMCO, efficacy and complication parameters, ventilator settings of mechanical ventilation and clinical outcomes. The statistical software of SPSS (version 11.5) was used for data analysis. RESULTS: 18 cases of novel H1N1 influenza with severe ARDS received ECMO. There were 9 males and 9 females (all pregnant). The mean age was (33 ± 11) years old. Eight were complicated with pulmonary barotraumas (6 of pneumothorax). Prior to ECMO, the patients underwent noninvasive and invasive positive pressure ventilation for 1 day and 60 hours respectively. Physiological parameters 2-6 hours prior to ECMO use were: (53 ± 14) mm Hg of PaO2/FiO2, (17 ± 5) cm H2O of positive end expiratory pressure (PEEP), 3.80 ± 0.29 of Murray lung injury score, (7.38 ± 0.10) of arterial pH, (3.3 ± 2.3) mmol/L of serum lactate, 16 ± 8 of APACHE II score. All patients treated venous-venous ECMO (VV-ECMO) for a mean duration of 8 days (range: 2 - 168). Settings of mechanical ventilation (prior to ECMO vs 2 hours post-ECMO) were: peak airway pressure (31 ± 7) vs (25 ± 6) cm H2O, respiratory rate (15 ± 4) vs (22 ± 6) breaths/min, FiO2 0.8 - 1.0 vs 0.35 - 0.50, PEEP (16 ± 5) vs (12 ± 4) cm H2O. Arterial blood gas (pH, PaO2 and PaCO2) post-ECMO of 2 hours and 24-hour significantly improved (P < 0.05). Seven patients died during ECMO, 11 patients were successfully weaned from ECMO. And 8 of them survived and were discharged. One patient stayed in ICU and 2 died in ICU. CONCLUSIONS: As an effective measure of respiratory supports, ECMO may provide pulmonary rest and improve gas exchanges in severe ARDS induced by novel H1N1 Influenza.

[Analysis of risk factors of prolonged intensive care unit stay of critically ill obstetric patients: a 5-year retrospective review in 3 hospitals in Beijing].

OBJECTIVE: To identify the risk factors of prolonged intensive care unit (ICU) stay of critically ill obstetric patients. METHODS: A retrospective analysis of cases of critically ill obstetric patients admitted to the ICUs of Peking University Third Hospital, Capital Medical University Affiliated Beijing Chaoyang Hospital, and PLA 306 Hospital from January 1st 2006 to December 31st 2010 was made. Data included demographics, causes of critical illness or complications that prompted ICU admission, the acute physiology and chronic health evaluation II (APACHEII) scores, the time intervals between onset of acute symptoms and ICU admission, laboratory test results, treatment measures, length of ICU stay and the final maternal mortality. Data were used to identify univariate and multivariate predictors for prolonged ICU stay. RESULTS: During the 5-year period there were 207 obstetric patients [mean age (31.74±2.32) years old, mean gestational age (34.86±4.72) weeks] were transferred to the ICU for critical care (42 ICU admissions per 10 000 deliveries), and among them 4 women died (mortality rate 1.93%). The pathogenesis of the cases could be divided into direct obstetric pathologies (n=138) and indirect or coincidental pathologies (n=69). The most common obstetric causes of admission were massive postpartum haemorrhage (n=42, 20.29%) and pregnancy associated hypertension (n=36, 17.39%), followed by acute fatty liver of pregnancy (AFLP, n=27, 13.04%), obstetric disseminated intravascular coagulation (DIC, n=23, 11.11%). The most common non obstetric causes of admission were acute heart failure (n=26, 12.56%) and acute respiratory failure (n=22, 10.63%), followed by severe acute pancreatitis (SAP, n=11, 5.31%). The incidence of prolonged ICU stay (ICU stay >3 days) was 52.66% (n=109). Univariate predictors of prolonged ICU stay included inadvertent antenatal care, high serum creatinine, abnormal international normalized ratio of prothrombin time (INR), abnormal oxygenation index (PaO(2)/FiO(2)), AFLP, obstetric DIC, SAP, use of mechanical ventilation, indications for inotropic support, and blood purification, and >24 hour interval between onset of acute symptoms and ICU admission. Multivariate modeling identified that inadvertent and irregular antenatal care [odds ratio (OR) 1.68, 95% confidence interval (95%CI) 1.14-2.69, P=0.011], PaO(2)/FiO(2) (OR 4.73, 95%CI 1.46-11.37, P=0.013), AFLP (OR3.21, 95%CI 1.13-4.76, P=0.026), DIC (OR 2.73, 95%CI 1.28-4.02, P=0.018), SAP (OR 4.78, 95%CI 1.83-7.42, P=0.021 ), indications for inotropic support (OR 1.96, 95%CI 1.24-3.15, P=0.001), blood purification (OR 11.02, 95%CI 3.04-58.02, P=0.015) and >24 hour interval between onset of acute symptoms and ICU admission (OR 2.04, 95%CI 1.21-4.25, P<0.001) were the independent predictors for prolonged ICU stay. CONCLUSION: The incidence of prolonged ICU stay is high for critically ill obstetric patients. Patients with identified multivariate predictors carry a high risk of prolonged ICU stay, they may benefit from enhanced regular antenatal care, prevention of critical obstetric and medical complications, shortening the interval between onset of acute symptoms and ICU admission and strengthening the support of organ function.

[Cultivation and morphology of nanobacteria in sera of patients with kidney calculi].

OBJECTIVE: To detect, culture, and characterize the nanobacteria (NB) from sera of patients with kidney calculi in our department. METHODS: Blood samples of 24 patients with kidney calculi and of 3 healthy volunteers in our department were collected for NB culture in this study. We used immunohistochemistry, von kossa staining, scanning electron microscopy (SEM), transmission electron microscopy (TEM) to investigate the appearance and components of cultural NB. RESULTS: Twenty-two blood samples out of 24 (91.67%) showed growth of NB, while no NB were detected in volunteers' blood samples. The infection rate of stone group was obviously higher than that of healthy volunteers. After a 4-week culture period, the light microscope revealed coccoid-shaped NB with a diameter of 100-500 nm, which could be identified by immunohistochemistry and von kossa staining. SEM and TEM (negative staining) revealed NB with a hollow interior coated in needle-like apatite crystals. Such nanoparticles could bud-off new ones and therefore appeared like living organisms. CONCLUSION: NB can be identified from sera of most patients involved in kidney calculi. It may have intimate relation to the formation of kidney calculi because the infection rate of NB blood samples of stone patients was significantly higher than that of healthy volunteers. Immunohistochemistry, von kossa staining, SEM and TEM are special methods for identifying NB from different aspects. The appearance and character are important points to distinguish NB from other nano-sized particles.

Dynamic quantification of avian influenza H7N9(A) virus in a human infection during clinical treatment using droplet digital PCR.

This study involved a human infection with avian influenza H7N9(A) virus in Zhejiang province, the first one after implementing the closure measures of living poultry markets in China. The clinical symptoms, epidemiological and virological characteristics of the case were described briefly, and as the emphasis, H7N9 virus was detected quantitatively and continuously from the collected samples in 10 different periods of the patient's treatment in order to reveal changes of viral load in patient's body during the treatment. This study first used reverse-transcription droplet digital PCR (RT-ddPCR) assays to monitor viral load dynamically for human H7N9 infection, synchronously performing real-time RT-PCR as a reference technology to obtain more comprehensive data for comparison. Our results indicated that RT-ddPCR compared to real-time RT-PCR is more sensitive and accurate for quantifying H7N9 viral load without the use of standard curves. Furthermore it can provide reference data for clinical policies including infectivity judgement, ward transferring and therapy adjustment for the patient during treatment.

Digital subtraction angiography imaging characteristics of patients with extra-intracranial atherosclerosis and its relationship to stroke.

To investigate the angiographic characteristics and clinical features in patients with suspected extra-intracranial atherosclerosis in a large cohort of Chinese population. On the basis of digital subtraction angiography characteristics, pathological morphology of extra-intracranial atherosclerosis was divided into tortuosity, kinking, coiling, and stenosis in 2,218 individuals aged 45-89 years. The degree of stenosis was further divided into low-grade (<30 %), intermediate-grade (30-69 %), and high-grade stenosis (≥70 %). Clinical manifestations were divided into transient ischemic attack, cerebral infarction and cerebral hemorrhage. The prevalence of tortuosity and stenosis were significantly higher in the extracranial arterial system than that of intracranial arterial system. The prevalence of tortuosity and kinking were significantly higher on the left side than the right side. The prevalence of mild and moderate stenosis in the internal carotid artery was significantly higher in the left side than the right side. The incidence of cerebral infarction was significantly higher in the internal carotid arterial (ICA) system than the vertebrobasilar arterial (VBA) system. Tortuosity is a common carotid abnormality in the Chinese population. The prevalence of ICA tortuosity is higher than that of VBA. The incidence of cerebral infarction in each atherosclerosis group was significantly higher in ICA than that of VBA. The prevalence of stroke is higher in the ICA system than the VBA system. Kinkings and coilings may not have a clinical significance if these lesions are not associated with atheromatous plaques or carotid stenosis.

[Influence of avian influenza virus NS1 protein on the expression of IP-10 in BEAS-2B cells].

OBJECTIVE: To investigate the influence of avian influenza virus (AIV) NS1 protein on the expression of interferon-inducible protein 10 (IP-10). METHODS: NSI gene from virus A/Anhui/1/2005 (H5N1), NS1 gene inserted with 80-84 amino acids from virus A/Anhui/1/2005 (H5N1) and NS1 gene from virus A/Puerto Rico/8/1934 (H1N1) were cloned into the eukaryotic expression vector pEGFP-N1, and transfected into BEAS-2B cells, IP-10 expression level in transfected cells was detected by flow cytometry. RESULTS: Compared with the control group pEGFP-N1, expression of these three different NS1 genes can down-regulate the expression of IP-10 in BEAS-2B cells, but there is no significant difference as to the lower level among them. CONCLUSION: NS1 protein of A/Anhui/1/2005 (H5N1) can down-regulate the expression level of IP-10, but this may not clarify its relationship with the virulence of AIV.

[Codon optimization of the H5N1 influenza virus HA gene gets high expression in mammalian cells].

In order to improve the expression of human avian influenza virus hemagglutinin (HA) and meet the pandemic influenza vaccine needs, we optimized and synthesized the whole length of HA gene of H5N1 (A/Anhui/1/2005) influenza virus in accordance with the human's codon preference, and inserted it to the eukaryotic expression vector pDC315 to construct a eukaryotic expression vector pDC315-Mod. HA. This plasmid and the eukaryotic expression vector pDC315-Wt. HA containing wild HA gene were transfected into 293T cells respectively to compare the expression of HA protein. The results showed that according to the comparison and identification by indirect immunofluorescence assay and Western blot test, the expression of HA protein in 293T cells was significantly improved after codon optimization. This laid a foundation for pandemic influenza vaccine research.