3,833 research outputs found
Galaxy Activity in Merging Binary Galaxy Clusters
We present the results of a study of galaxy activity in two merging binary
clusters (A168 and A1750) using the Sloan Digital Sky Survey (SDSS) data
supplemented with the data in the literature. We have investigated the merger
histories of A168 and A1750 by combining the results from a two-body dynamical
model and X-ray data. In A168 two subclusters appear to have passed each other
and to be coming together from the recent maximum separation. In A1750, two
major subclusters appear to have started interaction and to be coming together
for the first time. We find an enhanced concentration of the galaxies showing
star formation (SF) or active galactic nuclei (AGN) activity in the region
between two subclusters in A168, which were possibly triggered by the cluster
merger. In A1750, we do not find any galaxies with SF/AGN activity in the
region between two subclusters, indicating that two major subclusters are in
the early stage of merging.Comment: 14 pages, 12 figures. To appear in MNRA
Clinical Usefulness of Preoperative and Postoperative Chest Computed Tomography for Colorectal Cancer
Purpose: This research sought to identify the utility value of chest computed tomography (CT) when it comes to the diagnosis of lung metastasis in cases of colorectal cancer. Methods: From September 2004 to January 2008, 266 patients who were treated for colorectal cancer at Department of Surgery, Hanyang University College of Medicine, were divided into two groups: one that underwent preoperative and postoperative periodical chest CT (periodical inspection group, PIG; May 2006 to January 2008, 135 patients) and one that did not undergo periodical chest CT (non-periodical inspection group, NPIG; September 2004 to April 2006, 131 patients) for comparison. Results: The overall lung metastasis diagnosis rates did not manifest any significant difference. The times to diagnose lung metastasis patients were 6.3 months and 15.7 months for the PIG and the NPIG, respectively (P = 0.022). The size of the metastatic lung nodule was smaller in the PIG than in the NPIG (< 1 cm in 9/9 patients vs. < 1 cm in 6/9 patients in the PIG and the NPIG, respectively; P = 0.02). A solitary lung metastasis was more frequently found in the PIG (5/9 patients) than in the NPIG (1/11 patients) (P = 0.024). During the follow-up period, 100% (2/2 patients) and 60% (3/5 patients) of the patients in the PIG and the NPIG, respectively, with stage III cancer underwent a lung metastasectomy (P = 0.002). Conclusion: Chest CT enables early diagnosis with a smaller size and a lower number of lung metastases in patients with colorectal cancer. Moreover, pulmonary the rate of the pulmonary resection for selected patients may be improved. However, the contribution of chest CT to increasing the survival rate must be investigated in a prospective randomized study. ?? 2010 The Korean Society of Coloproctology
Immobilization of Saccharomyces Cerevisiae in Rice Hulls for Ethanol Production
The whole cell immobilization in ethanol fermentation can be done by using natural carriers or through synthetic carriers. All of these methods have the same purpose of retaining high cell concentrations within a certain defined region of space which leads to higher ethanol productivity. Lignocellulosic plant substance represents one of highly potential sources in ethanol production. Some studies have found that cellulosic substances substances can also be used as a natural carrier in cell immobilization by re-circulating pre-culture medium into a reactor. In this experiment, ricehulls without any treatment were used to immobilize Saccharomyces cerevisiae through semi solid state incubation combined with re-circulating pre-culture medium. The scanning electron microscopy (SEM) pictures of the carrier show that the yeast cells are absorbed and embedded to the rice hull pore. In liquid batch fermentation system with an initial sugar concentration of 50 g/L, nearly 100% total sugar was consumed after 48 hours. This resulted in an ethanol yield of 0.32 g ethanol/g glucose, which is 62.7% of the theoretical value. Ethanol productivity of 0.59 g/(L.h) is 2.3 fold higher than that of free cells which is 0.26 g/(L.h). An effort to reuse the immobilized cells in liquid fermentation system showed poor results due to cell desorption in the first batch which led to high sugar concentration inhibitory effect in the second batch fermentation. This might be solved by using semi solid fermentation process in the future work
Accretion, Growth of Supermassive Black Holes, and Feedback in Galaxy Mergers
Super-Eddington accretion is very efficient in growing the mass of a black
hole: in a fraction of the Eddington time its mass can grow to an arbitrary
large value if the feedback effect is not taken into account. However, since
super-Eddington accretion has a very low radiation efficiency, people have
argued against it as a major process for the growth of the black holes in
quasars since observations have constrained the average accretion efficiency of
the black holes in quasars to be \ga 0.1. In this paper we show that the
observational constraint does not need to be violated if the black holes in
quasars have undergone a two-phase growing process: with a short
super-Eddington accretion process they get their masses inflated by a very
large factor until the feedback process becomes important, then with a
prolonged sub-Eddington accretion process they have their masses increased by a
factor \ga 2. The overall average efficiency of this two-phase process is
then \ga 0.1, and the existence of black holes of by redshift
6 is easily explained. Observational test of the existence of the
super-Eddington accretion phase is briefly discussed.Comment: 11 pages, 4 figures. Submitted to MNRA
Two Lung Masses with Different Responses to Pemetrexed
We described here a patient who had two lung masses. Although the two masses had the same histology and a similar good response to initial chemotherapy with gemcitabine and carboplatin, the response to pemetrexed as a second-line treatment was different after re-growth of the tumors. These two lung masses could have originated from different clones or they could have progressed through different paths of molecular pathogenesis after metastasis, which would lead to different tumor characteristics, including their chemosensitivity. Regardless of their pathogenetic mechanisms, it seems important to recognize that tumors with the same histology that develop in one patient can have different responses to drugs
Probing the nanoscale phase separation in binary photovoltaic blends of poly(3-hexylthiophene) and methanofullerene by energy transfer
The generation of charge carriers in organic photovoltaic devices requires exciton diffusion to an interface of electron donor and acceptor materials, where charge separation occurs. We report a time resolved study of fluorescence quenching in films of poly(3-hexylthiophene) containing a range of fractions of the electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We show that energy transfer from P3HT to PCBM helps to bring excitons to the interface, where they dissociate into charge carriers. Fluorescence quenching in blends with ≤50 wt% of PCBM is controlled by exciton diffusion in P3HT. This allows us to estimate the average size of PCBM domains to be about 9 nm in the 1:1 blend. The implications for polymer solar cells are discussed
Integrated stratigraphy of the Waitakian-Otaian Stage boundary stratotype, Early Miocene, New Zealand
The base of the type section of the Otaian Stage at Bluecliffs, South Canterbury, is recognised as the stratotype for the boundary between the Waitakian and Otaian Stages. Principal problems with the boundary are the restriction of existing bioevent proxies to shelf and upper slope environments and its uncertain age. These topics are addressed by a multidisplinary study of a 125 m section about the boundary, which examines its lithostratigraphy, depositional setting, biostratigraphy, correlation, and geochronology.
The lower siltstone lithofacies (0-38.5 m) was deposited at upper bathyal depths (200-600 m) in a marginal basin which was partially sheltered from fully oceanic circulation by a submarine high and islands. The site was covered by cool-temperate water and was probably adjacent to the Subtropical Convergence. This unit is succeeded by the banded lithofacies (38.5-106 m) and the upper siltstone lithofacies (basal 19 m studied). Paleodepth probably declined up-sequence, but deposition at shelf depths is not definitely indicated. A cyclic pattern of abundance spikes in benthic and planktonic foraminifera commences 9 m above base and extends to 73 m in the banded lithofacies. Oxygen isotope excursions (up to 2.08%) in Euuvigerina miozea and Cibicides novozelandicus are greatest within the interval containing the abundance spikes. The stage boundary occurs in the banded lithofacies at the highest abundance spike (73 m). Although condensed intervals might affect the completeness of the section, they are not associated with sedimentary discontinuities, and we consider that the section is suitable as a biostratigraphic reference.
Spores, pollens, dinoflagellates, calcareous nannofossils, foraminifera, bryozoans, and ostracods are preserved near the boundary, but molluscs principally occur higher, in the shallower upper siltstone lithofacies. Siliceous microfossils are rare. There is considerable scope for further biostratigraphic research.
The primary event marking the boundary at 73 m is the appearance of the benthic foraminifer Ehrenbergina marwicki. This is a distinctive and widely distributed event but is restricted to shelf and upper bathyal environments. Supplementary events in planktonic foraminifera and calcareous nannofossils were researched. Highest occurrences of Globigerina brazieri and G. euapertura are recorded at 47 and 58 m. There is a marked decline in relative abundance of Paragloborotalia spp. at 62 m. Helicosphaera carteri becomes more abundant than H. euphratis between 56 and 87 m. These events are not exact proxies for the boundary but they may usefully indicate proximity to it. They occur in the interval of prominent spikes in foraminiferal abundance.
The Waitakian-Otaian boundary is dated at 21.7 Ma by strontium isotopes. Stable primary remanence could not be determined in a pilot paleomagnetic study of Bluecliffs specimens. However, specimens trended towards reversed polarity, and remagnetisation great circle analysis will allow directions to be calculated in future collections
Conservative management for postprostatectomy urinary incontinence
BACKGROUND: Urinary incontinence is common after radical prostatectomy and can also occur in some circumstances after transurethral resection of the prostate (TURP). Conservative management includes pelvic floor muscle training with or without biofeedback, electrical stimulation, extra-corporeal magnetic innervation (ExMI), compression devices (penile clamps), lifestyle changes, or a combination of methods. OBJECTIVES: To determine the effectiveness of conservative management for urinary incontinence up to 12 months after transurethral, suprapubic, laparoscopic, radical retropubic or perineal prostatectomy, including any single conservative therapy or any combination of conservative therapies. SEARCH METHODS: We searched the Cochrane Incontinence Group Specialised Register (5 February 2014), CENTRAL (2014, Issue 1), EMBASE (January 2010 to Week 3 2014), CINAHL (January 1982 to 18 January 2014), ClinicalTrials.gov and World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (both searched 29 January 2014), and the reference lists of relevant articles. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials evaluating conservative interventions for urinary continence in men after prostatectomy. DATA COLLECTION AND ANALYSIS: Two or more review authors assessed the methodological quality of the trials and abstracted data. We tried to contact several authors of included studies to obtain extra information. MAIN RESULTS: Fifty trials met the inclusion criteria, 45 in men after radical prostatectomy, four trials after TURP and one trial after either operation. The trials included 4717 men of whom 2736 had an active conservative intervention. There was considerable variation in the interventions, populations and outcome measures. Data were not available for many of the pre-stated outcomes. Men's symptoms improved over time irrespective of management.There was no evidence from eight trials that pelvic floor muscle training with or without biofeedback was better than control for men who had urinary incontinence up to 12 months after radical prostatectomy; the quality of the evidence was judged to be moderate (for example 57% with urinary incontinence in the intervention group versus 62% in the control group, risk ratio (RR) for incontinence after 12 months 0.85, 95% confidence interval (CI) 0.60 to 1.22). One large multi-centre trial of one-to-one therapy showed no difference in any urinary or quality of life outcome measures and had narrow CIs. It seems unlikely that men benefit from one-to-one PFMT therapy after TURP. Individual small trials provided data to suggest that electrical stimulation, external magnetic innervation, or combinations of treatments might be beneficial but the evidence was limited. Amongst trials of conservative treatment for all men after radical prostatectomy, aimed at both treatment and prevention, there was moderate evidence of an overall benefit from pelvic floor muscle training versus control management in terms of reduction of urinary incontinence (for example 10% with urinary incontinence after one year in the intervention groups versus 32% in the control groups, RR for urinary incontinence 0.32, 95% CI 0.20 to 0.51). However, this finding was not supported by other data from pad tests. The findings should be treated with caution because the risk of bias assessment showed methodological limitations. Men in one trial were more satisfied with one type of external compression device, which had the lowest urine loss, compared to two others or no treatment. The effect of other conservative interventions such as lifestyle changes remained undetermined as no trials involving these interventions were identified. AUTHORS' CONCLUSIONS: The value of the various approaches to conservative management of postprostatectomy incontinence after radical prostatectomy remains uncertain. The evidence is conflicting and therefore rigorous, adequately powered randomised controlled trials (RCTs) which abide by the principles and recommendations of the CONSORT statement are still needed to obtain a definitive answer. The trials should be robustly designed to answer specific well constructed research questions and include outcomes which are important from the patient's perspective in decision making and are also relevant to the healthcare professionals. Long-term incontinence may be managed by an external penile clamp, but there are safety problems
IMMOBILIZATION OF Saccharomyces cerevisiae IN RICE HULLS FOR ETHANOL PRODUCTION
The whole cell immobilization in ethanol fermentation can be done by using natural carriers or through synthetic carriers. All of these methods have the same purpose of retaining high cell concentrations within a certain defined region of space which leads to higher ethanol productivity. Lignocellulosic plant substance represents one of highly potential sources in ethanol production. Some studies have found that cellulosic substances substances can also be used as a natural carrier in cell immobilization by re-circulating pre-culture medium into a reactor. In this experiment, ricehulls without any treatment were used to immobilize Saccharomyces cerevisiae through semi solid state incubation combined with re-circulating pre-culture medium. The scanning electron microscopy (SEM) pictures of the carrier show that the yeast cells are absorbed and embedded to the rice hull pore. In liquid batch fermentation system with an initial sugar concentration of 50 g/L, nearly 100% total sugar was consumed after 48 hours. This resulted in an ethanol yield of 0.32 g ethanol/g glucose, which is 62.7% of the theoretical value. Ethanol productivity of 0.59 g/(L.h) is 2.3 fold higher than that of free cells which is 0.26 g/(L.h). An effort to reuse the immobilized cells in liquid fermentation system showed poor results due to cell desorption in the first batch which led to high sugar concentration inhibitory effect in the second batch fermentation. This might be solved by using semi solid fermentation process in the future work.Keywords: ethanol, fermentation, immobilization, rice hulls, yeast cell
- …