2,139 research outputs found
Estimate black hole masses of AGNs using ultraviolet emission line properties
Based on the measured sizes of broad line region of the reverberation-mapping
AGN sample, two new empirical relations are introduced to estimate the central
black hole masses of radio-loud high-redshift () AGNs. First, using
the archival spectroscopy data at UV band for the
reverberation-mapping objects, we obtained two new empirical relations between
the BLR size and \Mg/\C emission line luminosity. Secondly, using the newly
determined black hole masses of the reverberation-mapping sample for
calibration, two new relationships for determination of black hole mass with
the full width of half maximum and the luminosity of \Mg/\C line are also
found. We then apply the relations to estimate the black hole masses of AGNs in
Large Bright Quasar Surveyq and a sample of radio-loud quasars. For the objects
with small radio-loudness, the black hole mass estimated using the R_{\rm BLR}
- L_{\eMg/\eC} relation is consistent with that from the relation. But for radio-loud AGNs, the mass estimated
from the R_{BLR} - L_{\eMg/\eC} relation is systematically lower than that
from the continuum luminosity . Because jets could have
significant contributions to the UV/optical continuum luminosity of radio-loud
AGNs, we emphasized again that for radio-loud AGNs, the emission line
luminosity may be a better tracer of the ionizing luminosity than the continuum
luminosity, so that the relations between the BLR size and UV emission line
luminosity should be used to estimate the black hole masses of high redshift
radio-loud AGNs.Comment: 19 pages, 10 figure
Nasopharyngeal carcinoma (NPC) with liver metastasis in pregnancy
Introduction: Cancer in pregnancies is the second most common cause of death after trauma in woman of reproductive age and confounds about 0.1 to 0.2% of pregnancies1,2) and rarely nasopharyngeal carcinoma being the aetiology. Objective: This report describes a pregnant woman in which an advanced-stage NPC was diagnosed and managed accordingly with a review of some related literature reviews. Case report: 29 year old Chinese lady was diagnosed with nasopharyngeal carcinoma (NPC) during her third trimester with very short history. She initially presented to us at 34 weeks of pregnancy with a painless right neck swelling and a chronic non-productive cough for one month duration. She was initially thought to have tuberculous lymphadenitis. A routine rigid endoscopic nasopharyngoscope examination revealed a right Fossa of Rosenmuller (FOR) mass. Biopsy of the nasal mass and fine needle aspiration cytology (FNAC) of the neck swelling further confirmed nasopharyngeal carcinoma- non keratinizing type. After discussion with her obstetrician and the patient, she underwent an elective induction of labor at 36 weeks of gestation, and delivered a healthy 2.77 kg baby boy. Computer tomography (CT) neck, thorax and abdomen were performed 2 weeks postpartum. The imaging showed fullness of the right FOR with metastases to right level 2 cervical lymph node along with metastatic deposits in 2 segments of the liver. She was then referred to oncology unit for further management. Conclusion: In conclusion, high index of suspicion is important in detection of NPC even in pregnant ladies with suspicious neck swelling. Method of detecting NPC early in pregnancy is essential in order to give optimize treatment, achieve potential for full recovery and also reduced the adverse risk and complications associated with NPC
Meteorin regulates mesendoderm development by enhancing nodal expression
During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development. It is highly expressed in the inner cell mass of blastocysts and further in the epiblast and extra-embryonic ectoderm during gastrulation. Genetic ablation of the Meteorin gene resulted in early embryonic lethality, presumably due to impaired lineage allocation and subsequent cell accumulation. Embryoid body culture using Meteorin-null embryonic stem (ES) cells showed reduced Nodal expression and concomitant impairment of mesendoderm specification. Meteorin-null embryos displayed reduced levels of Nodal transcripts before the gastrulation stage, and impaired expression of Goosecoid, a definitive endoderm marker, during gastrulation, while the proximo-distal and anterior-posterior axes and primitive streak formation were preserved. Our results show that Meteorin is a novel regulator of Nodal transcription and is required to maintain sufficient Nodal levels for endoderm formation, thereby providing new insights in the regulation of mesendoderm allocation.open1113sciescopu
Adaptive loose optimization for robust question answering
Question answering methods are well-known for leveraging data bias, such as
the language prior in visual question answering and the position bias in
machine reading comprehension (extractive question answering). Current
debiasing methods often come at the cost of significant in-distribution
performance to achieve favorable out-of-distribution generalizability, while
non-debiasing methods sacrifice a considerable amount of out-of-distribution
performance in order to obtain high in-distribution performance. Therefore, it
is challenging for them to deal with the complicated changing real-world
situations. In this paper, we propose a simple yet effective novel loss
function with adaptive loose optimization, which seeks to make the best of both
worlds for question answering. Our main technical contribution is to reduce the
loss adaptively according to the ratio between the previous and current
optimization state on mini-batch training data. This loose optimization can be
used to prevent non-debiasing methods from overlearning data bias while
enabling debiasing methods to maintain slight bias learning. Experiments on the
visual question answering datasets, including VQA v2, VQA-CP v1, VQA-CP v2,
GQA-OOD, and the extractive question answering dataset SQuAD demonstrate that
our approach enables QA methods to obtain state-of-the-art in- and
out-of-distribution performance in most cases. The source code has been
released publicly in \url{https://github.com/reml-group/ALO}.Comment: 13 pages,8 figure
A phytophthora effector manipulates host histone acetylation and reprograms defense gene expression to promote infection
Immune response during pathogen infection requires extensive transcription reprogramming. A fundamental mechanism of transcriptional regulation is histone acetylation. However, how pathogens interfere with this process to promote disease remains largely unknown. Here we demonstrate that the cytoplasmic effector PsAvh23 produced by the soybean pathogen Phytophthora sojae acts as a modulator of histone acetyltransferase (HAT) in plants. PsAvh23 binds to the ADA2 subunit of the HAT complex SAGA and disrupts its assembly by interfering with the association of ADA2 with the catalytic subunit GCN5. As such, PsAvh23 suppresses H3K9 acetylation mediated by the ADA2/GCN5 module and increases plant susceptibility. Expression of PsAvh23 or silencing of GmADA2/GmGCN5 resulted in misregulation of defense-related genes, most likely due to decreased H3K9 acetylation levels at the corresponding loci. This study highlights an effective counter-defense mechanism by which a pathogen effector suppresses the activation of defense genes by interfering with the function of the HAT complex during infection
Shortening of primary cilia length is associated with urine concentration in the kidneys
Background The primary cilium, a microtubule-based cellular organelle present in certain kidney cells, functions as a mechano-sensor to monitor fluid flow in addition to various other biological functions. In kidneys, the primary cilia protrude into the tubular lumen and are directly exposed to pro-urine flow and components. However, their effects on urine concentration remain to be defined. Here, we investigated the association between primary cilia and urine concentration. Methods Mice either had free access to water (normal water intake, NWI) or were not allowed access to water (water deprivation, WD). Some mice received tubastatin, an inhibitor of histone deacetylase 6 (HDAC6), which regulates the acetylation of α-tubulin, a core protein of microtubules. Results WD decreased urine output and increased urine osmolality, concomitant with apical plasma membrane localization of aquaporin 2 (AQP2) in the kidney. After WD, compared with after NWI, the lengths of primary cilia in renal tubular epithelial cells were shortened and HDAC6 activity increased. WD induced deacetylation of α-tubulin without altering α-tubulin levels in the kidney. Tubastatin prevented the shortening of cilia through increasing HDAC6 activity and consequently increasing acetylated α-tubulin expression. Furthermore, tubastatin prevented the WD-induced reduction of urine output, urine osmolality increase, and apical plasma membrane localization of AQP2. Conclusions WD shortens primary cilia length through HDAC6 activation and α-tubulin deacetylation, while HDAC6 inhibition blocks the WD-induced changes in cilia length and urine output. This suggests that cilia length alterations are involved, at least in part, in the regulation of body water balance and urine concentration
Incidence and risk factors of subsyndromal delirium after curative resection of gastric cancer
Background: Subsyndromal delirium, a condition in which patients exhibit some, but not all, of the symptoms of delirium, can negatively affect the outcomes of patients with cancer. However, the incidence of subsyndromal delirium in patients with gastric cancer is unknown. Here, we investigated the incidence and risk factors of subsyndromal delirium after curative resection of gastric cancer. Methods: We recruited consecutive patients with gastric cancer who were scheduled for curative resection at a tertiary hospital. Patients' subsyndromal delirium symptoms were serially assessed preoperatively and 1, 2, 3, and 7 days postoperatively using the Delirium Rating Scale-Revised-98 (DRS-R-98). A DRS-R-98 score of 8-14 at any postoperative assessment was considered to indicate subsyndromal delirium. Sociodemographic and pre-/intraoperative clinical data were also assessed. Logistic regression analyses were used to determine the associated risk factors. Results: Data were analysed from 163 out of 217 eligible patients. Postoperative delirium occurred in one patient (0.6%) and subsyndromal delirium occurred in 19 patients (11.7%). Age >= 70 years (odds ratio, [OR] 3.85; 95% confidence interval [0], 136-10.92; p = 0.011) and education level <= 9 years (OR, 3.98; 95% CI, 139-11.41; p= 0.010) were independent risk factors of subsyndromal delirium after adjusting for preoperative cognitive function. Other pre-/intra-operative variables including anxiety/depression, poor sleep quality, and anaesthesia duration were not associated with subsyndromal delirium. Conclusions: In contrast to the low incidence of delirium among patients undergoing curative resection of gastric cancer, a substantial proportion of such patients experienced subsyndromal delirium. Considering the prognostic implications, more careful detection and management of subsyndromal delirium may be warranted in patients with gastric cance
A microencapsulation approach to design microbial seed coatings to boost wheat seed germination and seedling growth under salt stress
IntroductionSalt stress in seed germination and early seedling growth is the greatest cause of crop loss in saline-alkali soils. Microbial seed coating is an effective way to promote plant growth and salt resistance, but these coatings suffer from poor seed adhesion and low survival rates under typical storage conditions.MethodsIn this study, the marine bacterium Pontibacter actiniarum DSM 19842 from kelp was isolated and microencapsulated with calcium alginate using the emulsion and internal gelation method.ResultsCompared to unencapsulated seeds, the spherical microcapsules demonstrated a bacterial encapsulation rate of 65.4% and survival rate increased by 22.4% at 25°C for 60 days. Under salt stress conditions, the seed germination percentage of microcapsule-embedded bacteria (M-Embed) was 90%, which was significantly increased by 17% compared to the germination percentage (73%) of no coating treatment (CK). Root growth was also significantly increased by coating with M-Embed. Chlorophyll, peroxidase, superoxide dismutase, catalase, proline, hydrogen peroxide and malondialdehyde levels indicated that the M-Embed had the best positive effects under salt stress conditions.DiscussionTherefore, embedding microorganisms in suitable capsule materials provides effective protection for the survival of the microorganism and this seed coating can alleviate salt stress in wheat. This process will benefit the development of sustainable agriculture in coastal regions with saline soils
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