1,186 research outputs found
Quasi-Exact Solvability and the direct approach to invariant subspaces
We propose a more direct approach to constructing differential operators that
preserve polynomial subspaces than the one based on considering elements of the
enveloping algebra of sl(2). This approach is used here to construct new
exactly solvable and quasi-exactly solvable quantum Hamiltonians on the line
which are not Lie-algebraic. It is also applied to generate potentials with
multiple algebraic sectors. We discuss two illustrative examples of these two
applications: an interesting generalization of the Lam\'e potential which
posses four algebraic sectors, and a quasi-exactly solvable deformation of the
Morse potential which is not Lie-algebraic.Comment: 17 pages, 3 figure
Noncommutative effective theory of vortices in a complex scalar field
We derive a noncommutative theory description for vortex configurations in a
complex field in 2+1 dimensions. We interpret the Magnus force in terms of the
noncommutativity, and obtain some results for the quantum dynamics of the
system of vortices in that context
Biologically active Phytophthora mating hormone prepared by catalytic asymmetric total synthesis
A Phytophthora mating hormone with an array of 1,5-stereogenic centers has been synthesized by using our recently developed methodology of catalytic enantioselective conjugate addition of Grignard reagents. We applied this methodology in a diastereo- and enantioselective iterative route and obtained two of the 16 possible stereoisomers of Phytophthora hormone α1. These synthetic stereoisomers induced the formation of sexual spores (oospores) in A2 mating type strains of three heterothallic Phytophthora species, P. infestans, P. capsici, and P. nicotianae but not in A1 mating type strains. The response was concentration-dependent, and the oospores were viable. These results demonstrate that the biological activity of the synthetic hormone resembles that of the natural hormone α1. Mating hormones are essential components in the sexual life cycle of a variety of organisms. For plant pathogens like Phytophthora, sexual reproduction is important as a source of genetic variation. Moreover, the thick-walled oospores are the most durable propagules that can survive harsh environmental conditions. Sexual reproduction can thus greatly affect disease epidemics. The availability of synthetic compounds mimicking the activity of Phytophthora mating hormone will be instrumental for further unravelling sexual reproduction in this important group of plant pathogens.
ZrO2 Based materials as photocatalysts for 2-propanol oxidation by using UV and solar light irradiation and tests for CO2 reduction
Bare ZrO2, Ce doped ZrO2 and Er doped ZrO2 samples have been prepared by a hydrothermal process and have been used as photocatalysts for 2-propanol oxidation reaction in gas solid regime. Moreover, some preliminary tests have been carried out for CO2 reduction. The samples were physico-chemically characterized and both bare and doped ZrO2 based materials resulted active for oxidation and reduction reactions by using UV and solar irradiation. The reactivity results have been correlated with the compositional, structural and morphological features of the photocatalysts
Diagnostic and prognostic value of B4GALT1 hypermethylation and its clinical significance as a novel circulating cell-free DNA biomarker in colorectal cancer
Epigenetic modifications of glyco-genes have been documented in different types of cancer and are tightly linked to proliferation, invasiveness, metastasis, and drug resistance. This study aims to investigate the diagnostic, prognostic, and therapy-response predictive value of the glyco-gene B4GALT1 in colorectal cancer (CRC) patients. A Kaplan-Meier analysis was conducted in 1418 CRC patients (GEO and TCGA datasets) to assess the prognostic and therapy-response predictive values of the aberrant expression and methylation status of B4GALT1. Quantitative methylation-specific PCR (QMSP) and droplet digital quantitative methylation-specific PCR (dd-QMSP) were respectively used to detect hypermethylated B4GALT1 in metastasis and plasma in four cohorts of metastatic CRC cases (mCRC). Both the downregulated expression and promoter hypermethylation of B4GALT1 have a negative prognostic impact on CRC. Interestingly a low expression level of B4GALT1 was significantly associated with poor cetuximab response (progression-free survival (PFS) p = 0.01) particularly in wild-type (WT)-KRAS patients (p = 0.03). B4GALT1 promoter was aberrantly methylated in liver and lung metastases. The detection of hypermethylated B4GALT1 in plasma of mCRC patients showed a highly discriminative receiver operating characteristic (ROC) curve profile (area under curve (AUC) value 0.750; 95% CI: 0.592-0.908, p = 0.008), clearly distinguishing mCRC patients from healthy controls. Based on an optimal cut-off value defined by the ROC analysis, B4GALT1 yield a 100% specificity and a 50% sensitivity. These data support the potential value of B4GALT1 as an additional novel biomarker for the prediction of cetuximab response, and as a specific and sensitive diagnostic circulating biomarker that can be detected in CRC
Diagnosis and treatment outcomes of adult tuberculosis in an urban setting with high HIV prevalence in Sierra Leone: A retrospective study
OBJECTIVE: To assess the diagnosis, treatment outcomes, and predictors of mortality in adult tuberculosis (TB) patients in an urban setting with a high HIV prevalence. METHODS: A retrospective study was conducted of adult TB patients aged >/=15 years who were treated at Connaught Hospital in Freetown, Sierra Leone from January through December 2017. Multivariate logistic regression was used to identify predictors of mortality. RESULTS: Of 1127 TB cases notified in 2017, 1105 (98%) were tested for HIV, yielding a TB/HIV co-infection rate of 32.0%. Only HIV-tested cases (n=1105) were included in the final analysis. The majority were male (69.3%), aged 25-34 years (29.2%), and had pulmonary TB (96.3%). Treatment outcomes were as follows: 29.0% cured, 29.0% completed, 0.5% treatment failure, 24.2% lost to follow-up, 12.8% transferred/not evaluated, and 4.5% died. The majority of deaths (80.0%, 40/50) occurred within 2 months of TB treatment initiation. Age 65 years or older (adjusted odds ratio 3.48, 95% confidence interval 1.15-10.56; p=0.027) and HIV-positive status (adjusted odds ratio 3.50, 95% confidence interval 1.72-7.12; p=0.001) were independent predictors of mortality. CONCLUSIONS: Suboptimal TB treatment outcomes were observed in Sierra Leone in 2017. More local and international action is warranted to help achieve the 2035 global TB elimination targets
Impact of extracellular vesicle isolation methods on downstream mirna analysis in semen: A comparative study
Seminal plasma (SP) contains a unique concentration of miRNA, mostly contained in small extracellular vesicles (sEVs) such as exosomes, some of which could be clinically useful for diagnosis and/or prognosis of urogenital diseases such as prostate cancer (PCa). We optimized several exosome-EV isolation technologies for their use in semen, evaluating EV purifying effectiveness and impact on the downstream analysis of miRNAs against results from the standard ultracentrifugation (UC) method to implement the use of SP sEV_miRNAs as noninvasive biomarkers for PCa. Our results evidenced that commercial kits designed to isolate exosomes/EVs from blood or urine are mostly applicable to SP, but showed quantitative and qualitative variability between them. ExoGAG 3500x g and the miRCURY Cell/Urine/CSF 1500x g methods resulted as equivalent alternative procedures to UC for isolating exosomes/sEVs from semen for nanoparticle characteristics and quality of RNA contained in vesicles. Additionally, the expression profile of the altered semen sEV-miRNAs in PCa varies depending on the EV isolation method applied. This is possibly due to different extraction techniques yielding different proportions of sEV subtypes. This is evidence that the exosome-EV isolation method has a significant impact on the analysis of the miRNAs contained within, with important consequences for their use as clinical biomarkers. Therefore, miRNA analysis results for EVs cannot be directly extrapolated between different EV isolation methods until clear markers for delineation between microvesicles and exosomes are established. However, EV extraction methodology affects combined models (semen exosome miRNA signatures plus blood Prostate specific antigen (PSA) concentration for PCa diagnosis) less; specifically our previously described (miR-142-3p + miR-142-5p + miR-223-3p + PSA) model functions as molecular marker from EVs from any of the three isolation methods, potentially improving the efficiency of PSA PCa diagnosis
Oscillatons revisited
In this paper, we study some interesting properties of a spherically
symmetric oscillating soliton star made of a real time-dependent scalar field
which is called an oscillaton. The known final configuration of an oscillaton
consists of a stationary stage in which the scalar field and the metric
coefficients oscillate in time if the scalar potential is quadratic. The
differential equations that arise in the simplest approximation, that of
coherent scalar oscillations, are presented for a quadratic scalar potential.
This allows us to take a closer look at the interesting properties of these
oscillating objects. The leading terms of the solutions considering a quartic
and a cosh scalar potentials are worked in the so called stationary limit
procedure. This procedure reveals the form in which oscillatons and boson stars
may be related and useful information about oscillatons is obtained from the
known results of boson stars. Oscillatons could compete with boson stars as
interesting astrophysical objects, since they would be predicted by scalar
field dark matter models.Comment: 10 pages REVTeX, 10 eps figures. Updated files to match version
published in Classical and Quantum Gravit
The use of alteplase, although safe, does not offer clear clinical advantages when mild stroke is non-disabling
Introduction: It is unknown whether alteplase is effective and safe in patients with mild acute ischemic stroke (AIS). Determining whether symptoms are “disabling” or not is a crucial factor in the management of these patients. This study aimed to investigate the efficacy and safety of alteplase in patients with mild, non-disabling AIS. Methods: We included all consecutive patients admitted for AIS at our institution from January 2015 to May 2022 who presented a baseline NIHSS score of 0–5 and fit the criteria to receive intravenous thrombolysis. In order to select only subjects with non-disabling AIS, we excluded patients who scored more than 1 point in the following NIHSS single items: vision, language, neglect, and single limb. Patients who scored at least 1 point in the NIHSS consciousness item were excluded as well. This study is a retrospective analysis of a prospectively collected database. Results: After the application of the exclusion criteria, we included 319 patients, stratified into patients receiving and not receiving alteplase based on non-disabling symptoms. The two groups were comparable regarding demographic and clinical data. Rates of a 3-month favorable outcome, defined as a 3-month mRS score of 0–1, were similar, being 82.3% and 86.1% in the treated and untreated patients, respectively. Hemorrhagic complications and mortality occurred infrequently and were not affected by alteplase treatment. Discussion: This observational study suggests that the use of alteplase, although safe, is not associated with a better outcome in highly selected patients with non-disabling AIS
Identification of a novel synthetic lethal vulnerability in non-small cell lung cancer by co-targeting TMPRSS4 and DDR1
Finding novel targets in non-small cell lung cancer (NSCLC) is highly needed and identification of synthetic lethality between two genes is a new approach to target NSCLC. We previously found that TMPRSS4 promotes NSCLC growth and constitutes a prognostic biomarker. Here, through large-scale analyses across 5 public databases we identified consistent co-expression between TMPRSS4 and DDR1. Similar to TMPRSS4, DDR1 promoter was hypomethylated in NSCLC in 3 independent cohorts and hypomethylation was an independent prognostic factor of disease-free survival. Treatment with 5-azacitidine increased DDR1 levels in cell lines, suggesting an epigenetic regulation. Cells lacking TMPRSS4 were highly sensitive to the cytotoxic effect of the DDR1 inhibitor dasatinib. TMPRSS4/DDR1 double knock-down (KD) cells, but not single KD cells suffered a G0/G1 cell cycle arrest with loss of E2F1 and cyclins A and B, increased p21 levels and a larger number of cells in apoptosis. Moreover, double KD cells were highly sensitized to cisplatin, which caused massive apoptosis (~40%). In vivo studies demonstrated tumor regression in double KD-injected mice. In conclusion, we have identified a novel vulnerability in NSCLC resulting from a synthetic lethal interaction between DDR1 and TMPRSS4
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