140 research outputs found
Impact of multiple modes on the evolution of self-interacting axion condensate around rotating black holes
Ultra-light particles, such as axions, form a macroscopic condensate around a
highly spinning black hole by the superradiant instability. Due to its
macroscopic nature, the condensate opens the possibility of detecting the axion
through gravitational wave observations. However, the precise evolution of the
condensate must be known for the actual detection. For future observation, we
numerically study the influence of the self-interaction, especially interaction
between different modes, on the evolution of the condensate in detail. First,
we focus on the case when condensate starts with the smallest possible angular
quantum number. For this case, we perform the non-linear calculation and show
that the dissipation induced by the mode interaction is strong enough to
saturate the superradiant instability, even if the secondary cloud starts with
quantum fluctuations. Our result indicates that explosive phenomena such as
bosenova do not occur in this case. We also show that the condensate settles to
a quasi-stationary state mainly composed of two modes, one with the smallest
angular quantum number for which the superradiant instability occurs and the
other with the adjacent higher angular quantum number. We also study the case
when the condensate starts with the dominance of the higher angular quantum
number. We show that the dissipation process induced by the mode coupling does
not occur for small gravitational coupling. Therefore, bosenova might occur in
this case.Comment: 29 pages, 25 figures, 1 tabl
Coexistence of Continuous Variable Quantum Key Distribution and 7 12.5 Gbit/s Classical Channels
We study coexistence of CV-QKD and 7 classical 12.5 Gbit/s on-off keying
channels in WDM transmission over the C-band. We demonstrate key generation
with a distilled secret key rate between 20 to 50 kbit/s in experiments running
continuously over 24 hours.Comment: 2018 IEEE Summer Topicals, paper MD4.
The predictive variable regarding relapse in patients with ulcerative colitis after achieving endoscopic mucosal healing
Background/AimsMucosal healing (MH) is a proposed therapeutic goal for patients with ulcerative colitis (UC). Whether MH is the final goal for UC, however, remains under debate. Therefore, to elucidate clinical variables predicting relapse after MH in UC could be useful for establishing further therapeutic strategy. The aim of this study is to evaluate the predictive variables for relapse in UC-patients after achieving MH.MethodsFrom April 2010 to February 2015, 298 UC-patients treated at Kitano Hospital were retrospectively analyzed. MH was defined as Mayo endoscopic subscore of 0 or 1. The cumulative relapse free rate after achieving MH was evaluated. Predictive variables for relapse in UC-patients were assessed by Cox regression analysis.ResultsOf 298 UC-patients, 88 (29.5%) achieved MH. Of the 88 UC patients who achieved MH, 21 (23.9%) experienced UC-relapse. Based on Kaplan-Meier analysis, the cumulative relapse free rate at 1, 3, and 5 years after achieving MH was 87.9%, 70.2%, and 63.8%, respectively. The cumulative relapse free rate tended to be higher in the Mayo-0 group (76.9%) than in the Mayo-1 group (54.1%) at 5 years, although the difference was not statistically significant (P=0.313). Cox regression analysis indicated that the use of an immunomodulator was a predictive variable for relapse in UC-patients after achieving MH (P=0.035).ConclusionsOur data demonstrated that the prognosis of UC patients after achieving endoscopic MH could be based on UC refractoriness requiring an immunomodulator
Diagnosis and Treatment of Ulcerative Colitis with Cytomegalovirus Infection: Importance of Controlling Mucosal Inflammation to Prevent Cytomegalovirus Reactivation
Human cytomegalovirus (HCMV) is a member of the herpesvirus family. HCMV infection persists throughout the host lifespan in a latent state following primary infection. The ability of HCMV to escape control by the host immune system and its resulting reactivation suggests the importance of ongoing immune surveillance in the prevention of HCMV reactivation. HCMV is a common cause of opportunistic infection that causes severe and fatal disease in immune-compromised individuals. In inflammatory bowel disease patients, particularly those with ulcerative colitis (UC), HCMV is often reactivated because these patients are frequently treated with immunosuppressive agents. This reactivation exacerbates colitis. Additionally, HCMV infection can induce severe colitis, even in patients with UC who have never been treated with immunosuppressive agents. However, the role of HCMV in colonic inflammation in patients with UC remains unclear. Here, we present previous and current clinical data on the diagnosis and treatment of HCMV infection in UC. Additionally, our experimental data from a newly established mouse model mimicking UC with concomitant CMV infection clearly demonstrate that inflammation could result in the exacerbation of UC disease activity with induction of HCMV reactivation. In summary, optimal control of colonic inflammation should be achieved in UC patients who are refractory to conventional immunosuppressive therapies and are positive for HCMV
Sentinel-1 data to support monitoring deforestation in tropical humid forests
In recent years, methodologies for deforestation detection that use satellite data have been developed, primarily using optical data, which cannot detect deforestation in the presence of clouds. In this paper, we discuss a methodology developed to detect deforestation using Sentinel-1 data and that aims to complement typical early warning system based on optical satellite images such as one the Peruvian Government employs. The methodology was applied in three pilot areas in the tropical humid forest of Peru. Sentinel-1 data were acquired in Interferometric Wide Swath (IW) mode and VH polarization. We use a Gamma-Map filter to reduce the speckle noise, and the average of 3 chrono-sequentially continuous images to reduce the multi-temporal variation of the forest backscattering. This produced 6 time series for each pilot area. For the detection of deforestation, we used an algorithm based on the difference and ratio between the images before and after deforestation. The accuracy assessment revealed a user’s accuracy greater than 95%. We also made a multitemporal comparison between our results and the early warning tropical forest loss alerts that use only Landsat data, which showed that until the end of the study period 33.26% of the deforestation we detected was not detected by the early warning alerts that use Landsat data
SR-PSOX/CXCL16 plays a critical role in the progression of colonic inflammation.
Inflammatory bowel disease (IBD) is initiated and perpetuated by a dysregulated immune response to unknown environmental antigens such as luminal bacteria in genetically susceptible hosts. SR-PSOX/CXCL16, a scavenger receptor that binds phosphatidylserine and oxidised lipoprotein, has both phagocytic activity and chemotactic properties. The aim of this study was to investigate the role of SR-PSOX/CXCL16 in patients with IBD and experimental murine colitis
Slow hot carrier cooling in cesium lead iodide perovskites
Lead halide perovskites are attracting a great deal of interest for optoelectronic applications such as solar cells, LEDs, and lasers because of their unique properties. In solar cells, heat dissipation by hot carriers results in a major energy loss channel responsible for the Shockley–Queisser efficiency limit. Hot carrier solar cells offer the possibility to overcome this limit and achieve energy conversion efficiency as high as 66% by extracting hot carriers. Therefore, fundamental studies on hot carrier relaxation dynamics in lead halide perovskites are important. Here, we elucidated the hot carrier cooling dynamics in all-inorganic cesium lead iodide (CsPbI3) perovskite using transient absorption spectroscopy. We observe that the hot carrier cooling rate in CsPbI3 decreases as the fluence of the pump light increases and the cooling is as slow as a few 10 ps when the photoexcited carrier density is 7 × 1018 cm−3, which is attributed to phonon bottleneck for high photoexcited carrier densities. Our findings suggest that CsPbI3 has a potential for hot carrier solar cell applications
Efficacy and Safety of Long-Term Thiopurine Maintenance Treatment in Japanese Patients With Ulcerative Colitis
Background/AimsThe long-term clinical outcomes of patients with bio-naive ulcerative colitis (UC) who maintain remission with thiopurine are unclear. The aim of this study was to assess the long-term efficacy and safety of maintenance treatment with thiopurine in UC patients.MethodsThis was a retrospective observational cohort analysis conducted at a single center. Between December 1998 and August 2013, 59 of 87 patients with bio-naive UC who achieved remission after induction with treatments other than biologics were enrolled. Remission maintenance with thiopurine was defined as no concomitant treatment needed other than 5-aminosalicylate without relapse. We assessed the remission-maintenance rate, mucosal healing rate, colectomy-free rate, and treatment safety in UC patients who received thiopurine as maintenance treatment.ResultsThe 84-month cumulative remission-maintenance and colectomy-free survival rates in the UC patients who were receiving maintenance treatment with thiopurine and 5-aminosalicylate were 43.9% and 88.0%, respectively. Of the 38 patients who underwent colonoscopy during thiopurine maintenance treatment, 23 (60.5%) achieved mucosal healing. Of the 59 patients who achieved clinical remission with thiopurine, 6 patients (10.2%) discontinued the thiopurine therapy because of adverse events.ConclusionsOur study demonstrates the long-term efficacy and safety of thiopurine treatment in patients with bio-naive UC
Ischemic enteritis with intestinal stenosis
A 75-year-old man was admitted to our hospital with sudden onset of vomiting and abdominal distension. The patient was taking medication for arrhythmia. Computed tomography showed stenosis of the ileum and a small bowel dilatation on the oral side from the region of stenosis. A transnasal ileus tube was placed. Enteroclysis using contrast medium revealed an approximately 6-cm afferent tubular stenosis 10 cm from the terminal ileum and thumbprinting in the proximal bowel. Transanal double-balloon enteroscopy showed a circumferential shallow ulcer with a smooth margin and edema of the surrounding mucosa. The stenosis was so extensive that we could not perform endoscopic balloon dilation therapy. During hospitalization, the patient's nutritional status deteriorated. In response, we surgically resected the region of stenosis. Histologic examination revealed disappearance of the mucosal layer and transmural ulceration with marked fibrosis, especially in the submucosal layer. Hemosiderin staining revealed sideroferous cells in the submucosal layers. Based on the pathologic findings, the patient was diagnosed with ischemic enteritis. The patient's postoperative course was uneventful
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