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Doppler frequency estimation with high accuracy is very important for precise orbit determination and scientific studies in deep space exploration. In this paper, we propose a new method which implements cross correlation of only received signals from one single station to estimate Doppler frequency. The algorithm is relatively simple and it can achieve high accuracy even when signal to noise ratio (SNR) is very low. Moreover, the accuracy can be further improved by implementing frequency compensation, especially when the frequency dynamic range is high. Simulations were performed and results proved the validity of this method. X-band observations on MEX (Mars Express) and Juno were performed by a 13 m telescope of Wuhan University, which was equipped by two back ends, i.e. CDAS (Chinese Data Acquisition System) and RSR (Radio Science Receiver). Raw data recorded by the CDAS were processed by using the proposed method, and the estimated frequencies were in good agreement with the real time frequency estimation values by the RSR. What’s more, the accuracy by using cross correlation was higher than the one of RSR.

Differential phase delay is calculated for the differential one-way range (DOR) signals transmitted by Tianwen-1, the first Chinese Mars spacecraft that entered into the Mars orbit on 2021 February 10. Large decreases in the differential phase delay are identified in the DOR signals received by ground stations on 2021 March 23 and June 18. The decreases indicate sizable increases of the total electron content (TEC) along the DOR signal path between Tianwen-1 and the ground stations. The TEC increases are estimated to be 85 and 175 TEC units on 2021 March 23 and June 18, respectively. Evidence shows that they are caused by the sheath regions ahead of the coronal mass ejections (CMEs) that traversed the signal path on both days. The results represent the first observations of CME-related structures by the DOR signals and demonstrate the potential of DOR signals in remote sensing the interplanetary plasma structures in the solar wind.

In 2020, China will launch a Mars spacecraft composed of anorbiter and lander/rover. In this paper, the tracking techniques of the Marsspacecraft for a large radio telescope are analyzed and verifiedusing the Shanghai 65 m radio telescope (Tianma telescope). The measurementresults indicate that the pointing error caused by thermal deformation ofthe antenna body, atmospheric refraction, and the light-time effect should beconsidered when a large radio telescope is used to track the Marsspacecraft. When the light-time effect is not taken into account, thereceiving power is reduced by approximately 0.8 dB. When the elevation offset is 36and 72 arcsec, the reception capacity of the Tianma telescope is reduced byapproximately 0.8 and 3.5 dB, respectively. The results of this study thus have importantimplications for the Mars exploration.

The precise positioning of a lander is a key issue during in situ planetary exploration. This paper proposes an optimal weighting algorithm based on a Helmert-variance component estimation applied to VLBI phase delay data. We validated our algorithm on Chang’e 3 lander VLBI phase delay from the Chinese VLBI Network. We consider that the lander positioning accuracy achieved with our new algorithm is at least 53 % better, compared to previous estimations based on the same observations. The position of the lander based on continuous 4-day observations was estimated to be 44.1215 ° N ( ± 21.9 m), −19.5135 ° E ( ± 4.2 m) and −2632.7 m ( ± 18.9 m) with respect to a moon reference system. This result agrees well with the position derived from images taken by the Narrow Angle Camera on the Lunar Reconnaissance Orbiter.

Background Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS) is a common disease of urology, of which the pathogenesis and therapy remain to be further elucidated. Quercetin has been reported to improve the symptoms of CP/CPPS patients. We aimed to verify the therapeutic effect of quercetin on CP/CPPS and identify the mechanism responsible for it. Methods A novel CP/CPPS model induced with Complete Freund Adjuvant in Sprague Dawley rats was established and the prostates and blood specimens were harvested for further measurement after oral administration of quercetin for 4 weeks. Results Increased prostate index and infiltration of lymphocytes, up-regulated expression of IL-1β, IL-2, IL-6, IL-17A, MCP1, and TNFα, decreased T-SOD, CAT, GSH-PX, and increased MDA, enhanced phosphorylation of NF-κB, P38, ERK1/2, and SAPK/JNK were detected in CP/CPPS rat model. Quercetin was identified to ameliorate the histo-pathologic changes, decrease the expression of pro-inflammatory cytokines IL-1β, IL-2, IL-6, IL-17A, MCP1, and TNFα, improve anti-oxidant capacity, and suppress the phosphorylation of NF-κB and MAPKs. Conclusions Quercetin has specific protective effect on CP/CPPS, which is mediated by anti-inflammation, anti-oxidation, and at least partly through NF-κB and MAPK signaling pathways.

Background: Robot-assisted/laparoscopic intracorporeal ileal conduit (ICIC) has been reported in many experienced centers. Whether laparoscopic ICIC is superior to extracorporeal ileal conduit (ECIC) and whether laparoscopic ICIC should be promoted is still controversial. The aim of the study was to compare surgical and early oncological outcomes between patients undergoing laparoscopic radical cystectomy (LRC) with ICIC and ECIC. Methods: From January 2011 to June 2016, a total of 45 patients with bladder cancer underwent LRC with ileal conduit at our department, of whom 20 patients underwent LRC with ECIC and 25 patients underwent LRC with ICIC. Data of each patient’s characteristics, surgical outcomes, and short-term oncological outcomes were collected and analyzed. Results: LRC with ileal conduit was performed successfully on all 45 patients. There were no significant differences in patients' characteristics, mean total operative time, and mean estimated blood loss between the ICIC and ECIC groups. Median time of flatus and oral intake was shorter in the ICIC group compared with the ECIC group (3 vs. 5 days, P = 0.035; 4 vs. 5 days, P = 0.002). The complications rates did not show significant difference between the two groups within the first 90 days postoperatively (P = 0.538). Cancer staging showed 45% of patients in the ECIC group and 36% in the ICIC group had a pathologic stage of T3 or T4, and 50% of patients in the ECIC group and 44% in the ICIC group had a pathologic stage of N1 or N1+. Kaplan–Meier analysis showed no significant difference in overall survival at 24 months (60% vs. 62%, P = 0.857) between the ECIC and ICIC groups. Conclusions: ICIC after LRC may be successful with the benefits of faster recovery time. No significant difference was found in complications and oncological outcomes between ICIC and ECIC. However, larger series with longer follow-up are needed to validate this procedure. Key words: Ileal Conduit; Laparoscopy; Urinary Bladder Cancer

The third Chinese lunar spacecraft Chang'E-3 (CE3) was launched in 2013, and very long baseline interferometry (VLBI) observations were performed to improve accuracy of its orbit determination. During all the observation time, VLBI group delay experienced very large turbulence, which was up to hundreds of picoseconds, and with variation period of a few tens of seconds. However, VLBI group delay of another lunar spacecraft Chang'E-5-T1 (CE5T1), which was launched in 2014, did not show such turbulence. Influences from the troposphere, ionosphere, ground instruments, and phase characteristics of the on board antennas were considered at first, but none of these were the main cause of this large turbulence. Further investigations were made on differential phase delay turbulence, signal-to-noise ratio, and layout of spacecraft. The investigation results indicated that the large turbulence on group delay was caused by an interference of reflected signals from the CE3 spacecraft surface. Simulations proved that the delay error caused by signal reflection varied with frequency and therefore caused large turbulence on group delay. To minimize the multipath effect caused by signal reflection, some possible solutions are presented.

Chinese lunar spacecraft Chang’E-3 (CE3) and Chang’E5-T1 (CE5T1) were launched in 2013 and 2014, respectively and very long baseline interferometry (VLBI) observations were performed. Signal to noise ratio (SNR) of the Tianma (TM) station experienced peculiar variation, whereas SNRs of other stations were rather stable. Further, it happened only when observing spacecraft, and showed no such variation when performing astronomical observations. Moreover, it was distinctive on X band signals, whereas it was not noticed on S band signals. Analysis showed that the SNR variation was closely related with changing rate of elevation angle. Further investigations discovered that there were two sets of antenna control software at TM station, and the SNR variation originated from a bug in elevation control software used for observing spacecraft, not for astronomical observations. The bug caused big pointing error (around ± 30 as) on elevation angle of TM, which resulted in the peculiar SNR variation. It was not noticed on S band signals due to its relatively wide and flat main beam comparing with ± 30 as pointing error. However, the bug was fixed in software update in July, 2016, and the SNR of TM showed no such variation in 2017 and 2018.

The accuracy of lunar laser ranging (LLR) experiment has already increased to about 1 cm in recent years. When the LLR data joined to the lunar dynamical model updated from DE430, three independent numerically integrated ephemerides called DE436, EPM2017 and INPOP17a were released in 2017. It prompts us to reanalysis the lunar rotation parameters of the ephemerides, and also, especially estimation of the lunar free libration modes. To this end, we performed a Fourier analysis and least-square fit with the data from these three ephemerides to estimate lunar free librations. The results show that the free librations for each ephemeris are consistent with each other and with the previously published DE421 and DE430 free libration values; minor differences in detail may result from differences in the physical parameters contained in each ephemeris. The Euler angles integrated in each ephemeris however, show a significant difference before 1800, relative to the difference after 1970. This indicates that special attention must be paid to backward integration when building ephemerides.

Background Bladder cancer is a complex disease associated with high morbidity and mortality. Management of bladder cancer before radical cystectomy continues to be controversial. We compared the long-term efficacy of one-shot neoadjuvant intra-arterial chemotherapy (IAC) versus no IAC (NIAC) before radical cystectomy (RC) for bladder cancer. Methods We performed a retrospective review of patients who underwent either one-shot IAC or NIAC before RC between October 2006 and November 2015. A propensity-score matching (1:3) was performed based on key characters. The Kaplan-Meier method was utilized to estimate survival probabilities, and the log-rank test was used to compare survival outcomes between different groups. A multivariable Cox proportional hazard model was used to estimate survival outcomes. Results Twenty-six patients were treated using IAC before RC, and 123 NIAC patients also underwent RC. After matching, there was no significant difference between groups in baseline characteristics, perioperative variables, complication outcomes or tumor characteristics. Compared with clinical tumor stages, pathological tumor stages demonstrated a significant decrease (P = 0.002) in the IAC group. There was no significant difference in overall survival (OS, p = 0.354) or cancer-specific survival (CSS, p = 0.439) between the groups. Among all patients, BMI significantly affected OS (p = 0.004), and positive lymph nodes (PLN) significantly affected both OS (pp = 0.010). Conclusions One-shot neoadjuvant IAC before RC shows safety and tolerability and provides a significant advantage in pathological downstaging but not in OS or CSS. Further study of neoadjuvant combination therapeutic strategies with RC is needed.

Chang’E-3 spacecraft was orbiting the Moon from December 6–14, 2013, and very long baseline interferometry (VLBI) observations were performed to improve the accuracy of its orbit determination. In the process of recording VLBI raw data, 2 bits quantization was implemented. Interesting phenomenon was that signal-to-noise ratio (SNR) of each VLBI station experienced periodical change and had large variation on amplitude while in the Moon’s orbit, whereas SNR kept in a stable level after Chang’E-3 landed on the Moon. Influence of varying elevation angle on SNR was analyzed and compensation of 2 bits quantization harmonics to SNR calculation was investigated. Most importantly, telescope system noise temperature increase caused by the Moon was computed along the time of Chang’E-3 orbiting the Moon, and well matched SNR changing trend in terms of correlation coefficients.

Additional file 1: Table S1. Pathological staging before and after surgery in the NIAC group after matching (see Fig. S2), Table S2. Pathological staging before and after surgery in the IAC group (see Fig. S3), Table S3. Multivariable Cox proportional hazard model to estimate survival outcomes in IAC and NIAC groups, Table S4. Description of OS of diabetes groupings in the IAC group (see Fig. S4A), Table S5. Description of OS of BMI groupings in the NIAC group (see Fig. S4B), Table S6. Description of OS of PLN groupings in the NIAC group (see Fig. S4B), Table S7. Description of CSS of PLN groupings in the NIAC group (see Fig. S4B)

Context. Study the rotation of a celestial body is an efficient way to infer its interior structure, and then may give information of its origin and evolution. In this study, based on the latest shape model of Phobos from Mars Express (MEX) mission, the polyhedron approximation approach was used to simulate the gravity field of Phobos. Then, the gravity information was combined with the newest geophysical parameters such as GM and k2 to construct the numerical model of Phobos’ rotation. And with an appropriate angles transformation, we got the librational series respect to Martian mean equator of date. Aims. The purpose of this paper is to develop a numerical model of Phobos’ rotational motion that includes the elastic properties of Phobos. The frequencies analysis of the librational angles calculated from the numerical integration results emphasize the relationship between geophysical properties and dynamics of Phobos. This work will also be useful for a future space mission dedicated to Phobos. Methods. Based on the latest shape model of Phobos from MEX mission, we firstly modeled the gravity field of Phobos, then the gravity coefficients were combined with some of the newest geophysical parameters to simulate the rotational motion of Phobos. To investigate how the elastic properties of Phobos affect its librational motion, we adopted various k2 into our numerical integration. Then the analysis was performed by iterating a frequency analysis and linear least-squares fit of Phobos’ physical librations. From this analysis, we identified the influence of k2 on the largest librational amplitude and its phase. Results. We showed the first ten periods of the librational angles and found that they agree well with the previous numerical results which Phobos was treated as a perfectly rigid body. We also found that the maximum amplitudes of the three parameters of libration are also close to the results from a rigid model, which is mainly due to the inclination of Phobos and moments of inertia. The other amplitudes are slightly different, since the physics contained in our model is different to that of a previous study, specifically, the different low-degree gravity coefficients and ephemeris. The libration in longitude τ has the same quadratic term with previous numerical study, which is consistent with the secular acceleration of Phobos falling onto Mars. We investigated the influence of the tidal Love number k2 on Phobos’ rotation and found a detectable amplitude changes (0.0005°) expected in the future space mission on τ, which provided a potential possibility to constrain the k2 of Phobos by observing its rotation. We also studied the influence of Phobos’ orbit accuracy on its libration and suggested a simultaneous integration of orbit and rotation in future work.

Same-beam very long baseline interferometry observations were performed between the rover and the lander of Chang'E-3 and differential phase delay data were obtained with the minimum random error of about 0.03ps. These data were used to monitor the rover motions, as small as several centimeters, including movement, turning, and attitude adjustment. The relative position between the rover and the lander was precisely measured with an accuracy of 1m, which is an improvement of 10 times compared with that of the Apollo project.

Same beam VLBI is an important mean for the high precision ground-based navigation in lunar orbit rendezvous and docking. The probability of calculating the differential cycle ambiguity successfully by conventional real time resolving algorithms of multi-frequency same beam VLBI is low. However, the time delay is very long if the differential phase delay is calculated by post-processing method. The precision and the time delay of ground based navigation for two spacecrafts in lunar orbit rendezvous and docking will be affected. Under this background, a real time differential phase delay resolving algorithms of same beam VLBI which is applicable for lunar orbit rendezvous and docking is studied. The differential phase delay and cycle ambiguity resolving principles of multi-frequency same beam VLBI are introduced. The cause of cycle ambiguity error is analyzed according to the real-time and post-processing results of differential phase cycle ambiguity and differential phase delay. Some improvements are achieved by calculating accurate differential group delay and using matching searching method and continuity of differential phase, and a novel real time differential phase delay resolving algorithm is put forward. The result, calculated by using same beam VLBI observation data of SELENE mission, shows that the probability of getting the right cycle ambiguity is up to 95.49%, which is 5.45% higher than the conventional method.

When the signals from spacecrafts and radio sources transmits through the earths atmosphere and ionosphere, their phase occurs fluctuation, which has great influence on the measurement precision of the ground observing system such as VLBI. Using same beam VLBI data of 1 year which were got from two satellites (Rstar and Vstar) in Japanese lunar exploration project SELENE, we studied the Allan standard deviation and the structure function of correlation phase fluctuations of Rstar and Vstar, and differential correlation phase fluctuation between Rstar and Vstar on six baselines. We also obtained Allan standard deviation of phase fluctuations of Rstar and differential phase fluctuation between Rstar and Vstar at each station based on the 6 baseline data. In addition, we obtained the relationship model between differential phase fluctuations of Rstar and Vstar and its separation angle at each station. In the range of time interval 8 τ τ 0, which obeys Kolmogorov disturbance theory. The relationship model between the root mean square of differential phase fluctuations of Rstar and Vstar and its separation angle at each station is φ =1.967 θ +0.738 deg/deg, and that on six baselines is φ =2.759 θ +1.069 deg/deg.

Purpose: To introduce our experience with intracorporeal ileal conduit and evaluate the safety and feasibility of this endoscopic urinary diversion. Materials and Methods: Between March 2014 and July 2017, thirty-six consecutive patients underwent laparoscopic radical cystectomy with intracorporeal ileal conduit. Patients’ demographic data, perioperative data, 90-days postoperative outcomes and complications were collected. This cohort were divided into two groups of 18 patients each by chronological order of the operations to facilitate comparison of clinical data. Data were evaluated using the students’ T test, Mann-Whitney test and Fisher's Exact test. Results: All surgeries were completed successfully with no conversion. Median total operating time and median intracorporeal urinary diversion time were 304 and 105 minutes, respectively. Median estimated blood loss was 200 mL, and median lymph node yield was 21. Twenty-six Clavien grade < 3 complications occurred within 30-days and 9 occurred within 30-90 days. Five Clavien grade 3-5 complications occurred within 30 days. No statistically significant differences were found between the two groups except for intracorporeal urinary diversion time. At median follow-up of 17.5 (range 3-42) months, 6 patients experienced tumor recurrence/metastasis and 4 of these patients died. Conclusions: Intracorporeal ileal conduit following laparoscopic radical cystectomy is safe, feasible and reproducible. With the accumulation of experience, the operation time can be controlled at a satisfactory level.