Short Recurrence Time Research Articles

Discovery of Two New Eruptions of the Ultrashort Recurrence Time Nova M31N 2017-01e* *Based on observations obtained with the Hobby-Eberly Telescope (HET), which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximillians-Universitaet Muenchen, and Georg-August Universitaet Goettingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E.

We report the recent discovery of two new eruptions of the recurrent nova M31N 2017-01e in the Andromeda galaxy. The latest eruption, M31N 2024-08c, reached R = 17.8 on 2024 August 06.85 UT, ∼2 months earlier than predicted. In addition to this recent eruption, a search of archival Palomar Transient Factory data has revealed a previously unreported eruption on 2014 June 18.46 UT that reached a peak brightness of R ∼ 17.9 approximately a day later. The addition of these two eruption timings has allowed us to update the mean recurrence time of the nova. We find 〈T rec〉 = 924.0 ± 7.0 days (2.53 ± 0.02 yr), which is slightly shorter than our previous determination. Thus, M31N 2017-01e remains the nova with the second shortest recurrence time known, with only M31N 2008-12a being shorter. We also present a low-resolution spectrum of the likely quiescent counterpart of the nova, a ∼20.5 mag evolved B star displaying an ∼14.3 days photometric modulation.

The Accelerating Decline of the Mass Transfer Rate in the Recurrent Nova T Pyxidis* * Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of University for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

The recurrent nova T Pyxidis (T Pyx) has erupted six times since 1890, with its last outburst in 2011, and the relatively short recurrence time between classical nova explosions indicates that T Pyx must have a massive white dwarf (WD) accreting at a high rate. It is believed that, since its outburst in 1890, the mass transfer rate in T Pyx was very large due to a feedback loop where the secondary is heated by the hot WD. The feedback loop has been slowly shutting off, reducing the mass transfer rate, and thereby explaining the magnitude decline of T Pyx from ∼13.8 (before 1890) to 15.7 just before the 2011 eruption. We present an analysis of the latest Hubble Space Telescope far-ultraviolet and optical spectra, obtained 12 yr after the 2011 outburst, showing that the mass transfer rate has been steadily declining and is now below its preoutburst level by about 40%: Ṁ∼1−3×10−7M⊙ yr−1 for a WD mass of ∼1.0–1.4 M ⊙, an inclination of 50°–60°, reddening of E(B − V) = 0.30 ± 0.05, and a Gaia Data Release 3 distance of 2860−471+816 pc. This steady decrease in the mass transfer rate in the ∼decade after the 2011 outburst is in sharp contrast with the more constant preoutburst ultraviolet continuum flux level from archival International Ultraviolet Explorer spectra. The flux (i.e., Ṁ ) decline rate is 29 times faster now in the last ∼decade than observed since 1890 to ∼2010. The feedback loop shut off seems to be accelerating, at least in the decade following its 2011 outburst. In all eventualities, our analysis confirms that T Pyx is going through an unusually peculiar short-lived phase.

Ticking away: The long-term X-ray timing and spectral evolution of eRO-QPE2

Quasi-periodic eruptions (QPEs) are repeated X-ray flares from galactic nuclei that recur every few hours to days, depending on the source. Despite some diversity in the recurrence and amplitude of eruptions, their striking regularity has motivated theorists to associate QPEs with orbital systems. Among the known QPE sources, eRO-QPE2 has shown the most regular flare timing and luminosity since its discovery. We report here on its long-term evolution over 3.3 yr from discovery and find that: i) the average QPE recurrence time per epoch has decreased over time, albeit not at a uniform rate; ii) the distinct alternation between consecutive long and short recurrence times found at discovery has not been significant since; iii) the spectral properties, namely flux and temperature of both eruptions and quiescence components, have remained remarkably consistent within uncertainties. We attempted to interpret these results as orbital period and eccentricity decay coupled with orbital and disk precession. However, since gaps between observations are too long, we are not able to distinguish between an evolution dominated by just a decreasing trend, or by large modulations (e.g. due to the precession frequencies at play). In the former case, the observed period decrease is roughly consistent with that of a star losing orbital energy due to hydrodynamic gas drag from disk collisions, although the related eccentricity decay is too fast and additional modulations have to contribute too. In the latter case, no conclusive remarks are possible on the orbital evolution and the nature of the orbiter due to the many effects at play. However, these two cases come with distinctive predictions for future X-ray data: in the case of a decreasing trend, we expect all future observations to show a shorter recurrence time than the latest epoch, while in the case of large-amplitude modulations we expect some future observations to be found with a larger recurrence, hence an apparent temporary period increase.

Recurrence Pattern Is an Independent Surgical Prognostic Factor for Long-Term Oncological Outcomes in Patients with Hepatocellular Carcinoma.

The perioperative outcomes of a partial hepatectomy for hepatocellular carcinoma (HCC) have improved. However, high recurrence rates after a curative hepatectomy for HCC is still an issue. This study aimed to analyze the difference between various recurrence patterns. We retrospectively reviewed 754 patients with HCC who underwent a curative hepatectomy between January 2012 and March 2021. Patients with recurrent events were categorized into three types: regional recurrence (type I), multiple intrahepatic recurrence (type II), or presence of any distant metastasis (type III). The median follow-up period was 51.2 months. Regarding recurrence, 375 (49.7%) patients developed recurrence, with 244 (32.4%), 51 (6.8%), and 80 (10.6%) patients having type I, II, and III recurrence, respectively. Type III recurrence appeared to be more common in male patients and those with major liver resection, vascular invasion, a large tumor size (>5 cm), a higher tumor grade, and higher levels of AST and AFP (p < 0.05). Patients who had distant metastasis at recurrence had the shortest recurrence time and the worst overall survival (p < 0.001 and p < 0.001). our study demonstrated that recurrence with distant metastasis occurred earliest and had the worst outcome compared to regional or multiple intrahepatic recurrences.

PiR-1919609 Is an Ideal Potential Target for Reversing Platinum Resistance in Ovarian Cancer.

PIWI-interacting RNAs (piRNAs) are a type of noncoding small RNA that can interact with PIWI-like RNA-mediated gene silencing (PIWIL) proteins to affect biological processes such as transposon silencing through epigenetic effects. Recent studies have found that piRNAs are widely dysregulated in tumors and associated with tumor progression and a poor prognosis. Therefore, this study aimed to investigate the effect of piR-1919609 on the proliferation, apoptosis, and drug resistance of ovarian cancer cells. In this study, we used small RNA sequencing to screen and identify differentially expressed piRNAs in primary ovarian cancer, recurrent ovarian cancer, and normal ovaries. A large-scale verification study was performed to verify the expression of piR-1919609 in different types of ovarian tissue, including ovarian cancer tissue and normal ovaries, by RT-PCR and to analyze its association with the clinical prognosis of ovarian cancer. The expression of PIWILs in ovarian cancer was verified by RT-PCR, Western blotting and immunofluorescence. The effects of piR-1919609 on ovarian cancer cell proliferation, apoptosis and drug resistance were studied through in vitro and in vivo models. (1) piR-1919609 was highly expressed in platinum-resistant ovarian cancer tissues (p < 0.05), and this upregulation was significantly associated with a poor prognosis and a shorter recurrence time in ovarian cancer patients (p < 0.05). (2) PIWIL2 was strongly expressed in ovarian cancer tissues (p < 0.05). It was expressed both in the cytoplasm and nucleus of ovarian cancer cells. (3) Overexpression of piR-1919609 promoted ovarian cancer cell proliferation, inhibited apoptosis, and promoted tumor growth in nude mice. (4) Inhibition of piR-1919609 effectively reversed ovarian cancer drug resistance. In summary, we showed that piR-1919609 is involved in the regulation of drug resistance in ovarian cancer cells and might be an ideal potential target for reversing platinum resistance in ovarian cancer.

CRCS: An automatic image processing pipeline for hormone level analysis of Cushing’s disease

Due to the abnormal secretion of adreno-cortico-tropic-hormone (ACTH) by tumors, Cushing's disease leads to hypercortisonemia, a precursor to a series of metabolic disorders and serious complications. Cushing's disease has high recurrence rate, short recurrence time and undiscovered recurrence reason after surgical resection. Qualitative or quantitative automatic image analysis of histology images can potentially in providing insights into Cushing's disease, but still no software has been available to the best of our knowledge. In this study, we propose a quantitative image analysis-based pipeline CRCS, which aims to explore the relationship between the expression level of ACTH in normal cell tissues adjacent to tumor cells and the postoperative prognosis of patients. CRCS mainly consists of image-level clustering, cluster-level multi-modal image registration, patch-level image classification and pixel-level image segmentation on the whole slide imaging (WSI). On both image registration and classification tasks, our method CRCS achieves state-of-the-art performance compared to recently published methods on our collected benchmark dataset. In addition, CRCS achieves an accuracy of 0.83 for postoperative prognosis of 12 cases. CRCS demonstrates great potential for instrumenting automatic diagnosis and treatment for Cushing's disease.

The subglottic involvement is an independent risk factor for recurrence of laryngeal amyloidosis.

To analyze the risk factors for recurrence of laryngeal amyloidosis (LA). The clinical data of patients with LA admitted in the Otolaryngology Head and Neck Surgery Department of the Second Affiliated Hospital of Xi'an Jiaotong University from August 2009 to June 2022 were analyzed retrospectively; then, the risk factors for recurrence and their impacts on the recurrence time were also analyzed. Of the 44 patients with LA, the majority (38 cases, 86.4%) only involved one anatomical region and the others (6 cases, 13.6%) involved two laryngeal regions concurrently. Overall, the glottic region was the most commonly affected area (28 cases, 63.6%), followed by the supraglottic region (16 cases, 36.4%) and subglottic region (6 cases, 13.6%). In addition, all the lesions were categorized as isolated nodule (31.8%), submucosal localized deposition (52.3%), and submucosal diffuse deposition (15.9%) according to their morphologies under electronic laryngoscope. Finally, six patients (13.6%) had recurrence after operation with a median recurrence time of 24.5months, and subglottic involvement was confirmed to be an independent risk factor for recurrence of LA by univariate and multivariate logistic regression analyses (P < 0.05). Meanwhile, the patients with subglottic involvement presented as submucosal diffuse deposition had a considerable shorter recurrence time (t = 5.759, P = 0.005). The subglottic involvement is an independent risk factor for recurrence of LA.

Ultralow frictional healing explains recurring slow slip events.

Plate motion on shallow subduction megathrusts is accommodated by a spectrum of tectonic slip modes. However, the frictional properties and conditions that sustain these diverse slip behaviors remain enigmatic. Frictional healing is one such property, which describes the degree of fault restrengthening between earthquakes. We show that the frictional healing rate of materials entrained along the megathrust at the northern Hikurangi margin, which hosts well-characterized recurring shallow slow slip events (SSEs), is nearly zero (<0.0001 per decade). These low healing rates provide a mechanism for the low stress drops (<50 kilopascals) and short recurrence times (1 to 2 years) characteristic of shallow SSEs at Hikurangi and other subduction margins. We suggest that near-zero frictional healing rates, associated with weak phyllosilicates that are common in subduction zones, may promote frequent, small-stress-drop, slow ruptures near the trench.

Presence of secondary bladder cancer following radical nephroureterectomy for upper tract urothelial carcinoma: characteristics, risk factors, and predictive value

BackgroundTo assess the characteristics, predictive risk factors, and prognostic effect of secondary bladder cancer (SBCa) following radical nephroureterectomy (RNU) in upper tract urothelial carcinoma (UTUC).MethodsUsing the Surveillance, Epidemiology, and End Results database, the authors analyzed clinicopathologic characteristics and survival data from 472 UTUC patients with SBCa after RNU, between 2004 and 2017. Cox’s proportional hazard regression model was implemented to identify independent predictors associated with post-recurrence outcomes. The threshold for statistical significance was p < 0.05.ResultsIn total, 200 Ta-3N0M0 localized UTUC patients with complete data were finally included. With a median follow-up of 71.0 months (interquartile ranges [IQR] 36.0 -103.8 months), 52.5% (n = 105) had died, with 30.5% (n = 61) dying of UTUC. The median time interval from UTUC to SBCa was 13.5 months (IQR 6.0–40.8 months). According to multivariable Cox regression analysis, patients with SBCa located at multiple sites, advanced SBCa stage, higher SBCa grade, elderly age and a shorter recurrence time, encountered worse cancer-specific survival (CSS), all p < 0.05.ConclusionFor primary UTUC patients with SBCa after radical surgery, advanced age, multiple SBCa sites, shorter recurrence time, higher SBCa stage, and grade proved to be significant independent prognostic factors of CSS. We ought to pay more attention to SBCa prevention as well as to earlier signs which may increase the likelihood of early detection. Having the ability to manage what may be seen as the superficial SBCa signs may enable us to improve survival but further research is required.

Postoperative outcomes and recurrence patterns of intermediate-stage hepatocellular carcinoma dictated by the sum of tumor size and number

The selection criteria for Barcelona Clinic Liver Cancer (BCLC) intermediate-stage hepatocellular carcinoma (HCC) patients who would truly benefit from liver resection (LR) remain undefined. To identify BCLC-B HCC patients more suitable for LR. We included patients undergoing curative LR for BCLC stage A or B multi-nodular HCC (MNHCC) and stratified BCLC-B patients by the sum of tumor size and number (N + S). Overall survival (OS), recurrence-free survival (RFS), recur-rence-to-death survival (RTDS), recurrence patterns, and treatments after recurrence in BCLC-B patients in each subgroup were compared with those in BCLC-A patients. In total, 143 patients who underwent curative LR for MNHCC with BCLC-A (n = 25) or BCLC-B (n = 118) were retrospectively analyzed. According to the N + S, patients with BCLC-B HCC were divided into two subgroups: BCLC-B1 (N + S ≤ 10, n = 83) and BCLC-B2 (N + S > 10, n = 35). Compared with BCLC-B2 patients, those with BCLC-B1 had a better OS (5-year OS rate: 67.4% vs 33.6%; P < 0.001), which was comparable to that in BCLC-A patients (5-year OS rate: 67.4% vs 74.1%; P = 0.250), and a better RFS (median RFS: 19 mo vs 7 mo; P < 0.001), which was worse than that in BCLC-A patients (median RFS: 19 mo vs 48 mo; P = 0.022). Further analysis of patients who developed recurrence showed that both BCLC-B1 and BCLC-A patients had better RTDS (median RTDS: Not reached vs 49 mo; P = 0.599), while the RTDS in BCLC-B2 patients was worse (median RTDS: 16 mo vs not reached, P < 0.001; 16 mo vs 49 mo, P = 0.042). The recurrence patterns were similar between BCLC-B1 and BCLC-A patients, but BCLC-B2 patients had a shorter recurrence time and a higher proportion of patients had recurrence with macrovascular invasion and/or extrahepatic metastasis, both of which were independent risk factors for RTDS. BCLC-B HCC patients undergoing hepatectomy with N + S ≤ 10 had mild recurrence patterns and excellent OS similar to those in BCLC-A MNHCC patients, and LR should be considered in these patients.

M31N 2017-01e: Discovery of a Previous Eruption in this Enigmatic Recurrent Nova

We report the discovery of a previously unknown eruption of the recurrent nova M31N 2017-01e that took place on 2012 January 11. The earlier eruption was detected by Pan-STARRS and occurred 1847 days (5.06 yr) prior to the eruption on 2017 January 31 (M31N 2017-01e). The nova has now been seen to have had a total of four recorded eruptions (M31N 2012-01c, 2017-01e, 2019-09d, and 2022-03d) with a mean time between outbursts of just 929.5 ± 6.8 days (2.545 ± 0.019 yr), the second shortest recurrence time known for any nova. We also show that there is a blue variable source (〈V〉 = 20.56 ± 0.17, B − V ≃ 0.045), apparently coincident with the position of the nova, that exhibits a 14.3 days periodicity. Possible models of the system are proposed, but none are entirely satisfactory.

NuSTAR and AstroSat observations of thermonuclear X-ray bursts with short-recurrence times in 4U 1636−536

We report results from the spectro-timing analysis of the atoll source 4U 1636$-$536 observed with NuSTAR and AstroSat during its hard spectral state. In three observations of 207 ks total exposure, we identify 31 thermonuclear X-ray bursts including five doublets and a triplet. Recurrence time as short as 3.8 minutes is seen in one of the doublets. To the best of our knowledge, this is the shortest recurrence time known for this source. Our time-averaged spectroscopy during the bursts indicate the presence of an additional powerlaw or a blackbody component in a few cases, perhaps due to varying temperatures during bursts or plausible deviation from ideal blackbody behavior, however, it is difficult to probe this using the time-resolved spectroscopy owing to limited statistics. Time-resolved bursts are well fit using an absorbed blackbody model with temperatures varying between 1.7 and 2.2 keV. Burst oscillations around 581 Hz are detected with 3$\sigma$ confidence during the decay phase in two of the X-ray bursts. One of the burst oscillations is seen at 582 Hz, a frequency observed during the 2001 superburst in this source.

An 8‐Year‐Long Low‐Frequency Earthquake Catalog for Southern Cascadia

AbstractLow‐frequency earthquakes (LFEs) are small magnitude earthquakes with typical magnitude less than 2 and reduced amplitudes at frequencies greater than 10 Hz relative to ordinary small earthquakes. Their occurrence is often associated with tectonic tremor and slow‐slip events along the plate boundary in subduction zones and occasionally transform fault zones. They are usually grouped into families with all the earthquakes of a given family originating from the same small patch on the plate interface and recurring more or less episodically in a bursty manner. In this study, we extend the LFE catalog obtained by Plourde et al. (2015), https://doi.org/10.1002/2015gl064363 during an episode of high tremor activity in April 2008 to the 8‐year period 2004–2011. All of the tremors in the Boyarko et al. (2015), https://doi.org/10.1016/j.epsl.2015.06.026 catalog south of 42° North have associated LFE activity, but we have identified several smaller episodes of LFEs without associated tremor activity, and extend their catalog forward and backward by a total of about 3 years. As in northern Cascadia, the downdip LFE families have recurrence intervals several times smaller than the updip families. For the April 2008 Episodic Tremor and Slip event, the best recorded LFE families exhibit a strong tidal Coulomb stress sensitivity starting 1.5 days after the rupture front passes by each LFE family. The southernmost LFE family, which has been interpreted to be on the subduction plate boundary, near the updip limit of tremor, has a very short recurrence time. Also, these LFEs tend to occur during times when predicted tidal Coulomb stress is discouraging slip on the plate boundary. Both observations suggest that this LFE family may be on a different fault.

Rapid Bursts of Magnetically Gated Accretion in the Intermediate Polar V1025 Cen

Abstract Magnetically gated accretion has emerged as a proposed mechanism for producing extremely short, repetitive bursts of accretion onto magnetized white dwarfs in intermediate polars (IPs), but this phenomenon has not been detected previously in a confirmed IP. We report the 27 day TESS light curve of V1025 Cen, an IP that shows a remarkable series of 12 bursts of accretion, each lasting for less than 6 hours. The extreme brevity of the bursts and their short recurrence times (∼1–3 days) are incompatible with the dwarf-nova instability, but they are natural consequences of the magnetic gating mechanism developed by Spruit and Taam to explain the Type II bursts of the accreting neutron star known as the Rapid Burster. In this model, the accretion flow piles up at the magnetospheric boundary and presses inward until it couples with the star’s magnetic field, producing an abrupt burst of accretion. After each burst, the reservoir of matter at the edge of the magnetosphere is replenished, leading to cyclical bursts of accretion. A pair of recent studies applied this instability to the suspected IPs MV Lyr and TW Pic, but the magnetic nature of these two systems has not been independently confirmed. In contrast, previous studies have unambiguously established the white dwarf in V1025 Cen to be significantly magnetized. The detection of magnetically gated bursts in a confirmed IP therefore validates the extension of the Spruit and Taam instability to magnetized white dwarfs.

Predictive Value of Newly Diagnosed IgG Level in Patients with IgG-type Multiple Myeloma after Initial Treatment

To explore the predictive value of newly diagnosed IgG levels in the recurrence of IgG-type multiple myeloma (MM) patients after initial treatment. The clinical and pathological data of 91 patients newly diagnosed IgG-type MM who were hospitalized in the Department of Hematology of the Second People's Hospital of Yichang and Department of Oncology of The Affiliated Hospital of Jianghan University from April 2010 to March 2019 were collected. According to the median IgG level at the time of initial diagnosis, patients were divided into high IgG group and low IgG group. The recurrence time after initial treatment was followed up, and the correlation between newly diagnosed IgG level and recurrence was analyzed by univariate and multivariate analysis, as well as the influencing factors of IgG levels in order to predict furtherly the potential mechanism of recurrence. Univariate survival analysis showed that high revised international staging system (R-ISS) staging, high level of bone marrow plasma cell (BMPC), lactate dehydrogenase (LDH), creatinine, β2-microglobulin, and IgG, low level of hemoglobin and serum albumin, high-risk genetic risk, autologous hematopoietic stem cell transplantation (ASCT) were closely related to shortened recurrence time after initial treatment (all P<0.05). COX multivariate survival analysis showed that high R-ISS staging, high level of BMPC, β2-microglobulin, LDH, and IgG, low level of serum albumin, high-risk genetic risk, ASCT were independently associated with shorter recurrence time after initial treatment (all P<0.05). The median recurrence time of IgG MM patients with high and low IgG level was 30 (7-53) months and 42 (5-65) months, respectively. The cumulative recurrence rate of MM patients with high IgG level was significantly higher than that of patients with low level (χ2=7.982, P=0.005). Univariate analysis of the difference in IgG levels showed that high level of BMPC, urea nitrogen, blood creatinine, and low level of hemoglobin and serum albumin were closely related to high IgG level of IgG-type MM patients in initial diagnosis (all P<0.05). The logistic regression analysis of the differences in IgG levels showed that low level of serum albumin were independently correlated with high IgG levels in IgG-type MM patients in initial diagnosis (P<0.05). The higher the serum IgG concentration of IgG-type MM patients at first diagnosis, the earlier the recurrence, which is related to the low level of serum albumin, and can be used as a potential recurrence predictor after complete remission of IgG-type MM patients.

Discovery of Transition from Marginally Stable Burning to Unstable Burning after a Superburst in Aql X-1

Abstract Superbursts are long duration, rare, and extremely energetic thermonuclear explosions of neutron star low-mass X-ray binaries (NS LMXBs), which are proposed to be due to unstable carbon ignition. We report the superburst properties and consequences from Aql X–1 observed by the Neutron Star Interior Composition Explorer (NICER), the Monitor of All-sky X-ray Image, Swift, and Insight Hard X-ray Modulation Telescope (Insight-HXMT) on the MJD 59130.7. We found two faint type I X-ray bursts 9.44 days after the superburst with a short recurrence time of 7.6 minutes, which is the most accurate measurement of the quenching time in all NS LMXBs with observed superbursts. We also discovered mHz quasi-periodic oscillations in the frequency range 2.7–11.3 mHz immediately after the superburst, before and after the resumption of the first type I X-ray burst from NICER, Swift, and Insight-HXMT observations. For the first time, we observed the transition from superburst, via marginally stable burning to unstable burning in NS LMXBs. We compared the quenching time and the recurrence time of type I X-ray bursts with simulations.

Thermonuclear X-Ray Bursts with Late Secondary Peaks Observed from 4U 1608–52

Abstract We report the temporal and spectral analysis of three thermonuclear X-ray bursts from 4U 1608−52, observed by the Neutron Star Interior Composition Explorer (NICER) during and just after the outburst observed from the source in 2020. In two of the X-ray bursts, we detect secondary peaks 30 and 18 s after the initial peaks. The secondary peaks show a fast rise exponential decay-like shape resembling a thermonuclear X-ray burst. Time-resolved X-ray spectral analysis reveals that the peak flux, blackbody temperature, and apparent emitting radius values of the initial peaks are in agreement with X-ray bursts previously observed from 4U 1608−52, while the same values for the secondary peaks tend toward the lower end of the distribution of bursts observed from this source. The third X-ray burst, which happened during much lower accretion rates, did not show any evidence for a deviation from an exponential decay and was significantly brighter than the previous bursts. We present the properties of the secondary peaks and discuss the events within the framework of short recurrence time bursts or bursts with secondary peaks. We find that the current observations do not fit in standard scenarios and challenge our understanding of flame spreading.

The X-Ray Bursts of XTE J1739–285: A NICER Sample

Abstract In this work, we report on observations with the Neutron Star Interior Composition Explorer of the known neutron star X-ray transient XTE J1739–285. We observed the source in 2020 February and March, finding it in a highly active bursting state. Across a 20 day period, we detected 32 thermonuclear X-ray bursts, with an average burst recurrence time of . A timing and spectral analysis of the ensemble of X-ray bursts reveals homogeneous burst properties, evidence for short-recurrence time bursts, and the detection of a 386.5 Hz burst oscillation candidate. The latter is especially notable, given that a previous study of this source claimed a 1122 Hz burst oscillation candidate. We did not find any evidence of variability near 1122 Hz and instead find that the 386.5 Hz oscillation is the more prominent signal of the two burst oscillation candidates. Hence, we conclude it is unlikely that XTE J1739–285 has a submillisecond rotation period.

Sphincter of Oddi Laxity Alters Bile Duct Microbiota and Contributes to the Recurrence of Chelodocholithiasis

Background: Chelodocholithiasis is closely associated with bacterial infection and inflammation in the bile ducts. Our previous studies showed that sphincter of Oddi laxity (SOL) significantly altered the bile microbiota and might contribute to biliary stone recurrence. However, the direct association among SOL, bile microbiota, and chelodocholithiasis recurrence has not been well investigated. Methods: We recruited 202 patients with chelodocholithiasis, and obtained the bile samples from the common bile duct. We performed 16S rRNA gene analysis to characterize the bile microbiota, and analyzed the risk factors of chelodocholithiasis. Results: Distinct bile microbial communities were identified in patients with and without SOL with a significantly greater abundance of Rhizobiaceae in SOL patients. SOL patients had a higher risk of biliary stone recurrence with a considerably shorter recurrence time. The abundance of Clostridium was significantly higher in recurrent patients. SOL (P = 0.045, HR = 8.563) and pre-operative gamma-glutamyl transferase level (P = 0.037, HR = 1.002) were two independent risk factors of chelodocholithiasis recurrence. Conclusions: Chelodocholithiasis patients with and without SOL demonstrated significant differences in their microbial communities. SOL is a critical risk factor of chelodocholithiasis recurrence after surgery. The presence of Clostridium is potentially associated with SOL-induced chelodocholithiasis recurrence.

Sphincter of Oddi laxity alters bile duct microbiota and contributes to the recurrence of choledocholithiasis.

BackgroundCholedocholithiasis is closely associated with bacterial infection and inflammation in the bile duct. Our previous studies showed that sphincter of Oddi laxity (SOL) significantly altered the bile microbiota and might contribute to the recurrence of biliary stones. However, the direct association among SOL, the bile microbiota, and choledocholithiasis recurrence is unclear.MethodsWe prospectively recruited 202 patients with choledocholithiasis, and obtained bile samples from the common bile duct. We performed 16S ribosomal RNA gene analysis to characterize the bile microbiota and analyzed the risk factors for choledocholithiasis.ResultsDistinct bile microbial communities were identified in patients with and without SOL, with a significantly larger abundance of Rhizobiaceae in patients with SOL. Patients with SOL had a higher risk of biliary stone recurrence, with a considerably shorter recurrence time. The abundance of Clostridium was significantly higher in patients with stone recurrence. SOL [P=0.024, hazard ratio (HR) =10.800, 95% confidence interval (CI): 1.377–84.701] was an independent risk factor of choledocholithiasis recurrence.ConclusionsCholedocholithiasis patients with and without SOL demonstrated significant differences in their microbial communities. SOL is a critical risk factor for the recurrence of choledocholithiasis after surgery. The presence of Clostridium may be potentially associated with the recurrence of SOL-induced choledocholithiasis.