375 research outputs found
Efficient Hybrid Machine Learning Algorithm for text Classification
Text Mining and Text Classification are the most important and challenging task. Deriving high quality and relevant information form text is Text Mining and categorizing the text documents is done using the Text Classification. The real challenge in these areas is to address the problems like handling large text corpora, similarity of words in text documents, and association of text documents with a subset of class categories. The feature extraction and classi?cation of such text documents require an efficient machine learning algorithm which performs automatic text classification. The major drawback encountered in text classification and retrieval is determining whether a text is pertinent to the query. This work focuses on text classification by using the data mining techniques. A hybrid algorithm is proposed for classifying the text. The proposed algorithm combines the concepts of KNN, SVM and NB. The results obtained support the proposed hybrid algorithm in text classification
Microarray analysis of androgen-regulated gene expression in testis: the use of the androgen-binding protein (ABP)-transgenic mouse as a model
BACKGROUND: Spermatogenesis is an androgen-dependent process, yet the molecular mechanisms of androgens' actions in testis are poorly understood. Transgenic mice overexpressing rat androgen-binding protein (ABP) in their testes have reduced levels of intratesticular androgens and, as a result, show a progressive impairment of spermatogenesis. We used this model to characterize changes in global gene expression in testis in response to reduced bioavailability of androgens. METHODS: Total RNA was extracted from testes of 30-day old transgenic and wild-type control mice, converted to cRNA, labeled with biotin, and hybridized to oligonucleotide microarrays. Microarray results were confirmed by real-time reverse transcription polymerase chain reaction. RESULTS: Three-hundred-eighty-one genes (3.05% of all transcripts represented on the chips) were up-regulated and 198 genes (1.59%) were down-regulated by at least a factor of 2 in the androgen-deficient animals compared to controls. Genes encoding membrane proteins, intracellular signaling molecules, enzymes, proteins participating in the immune response, and those involved in cytoskeleton organization were significantly overrepresented in the up-regulated group. Among the down-regulated transcripts, those coding for extracellular proteins were overrepresented most dramatically, followed by those related to proteolysis, cell adhesion, immune response, and growth factor, cytokine, and ion channel activities. Transcripts with the greatest potential impact on cellular activities included several transcription factors, intracellular signal transducers, secreted signaling molecules and enzymes, and various cell surface molecules. Major nodes in the up-regulated network were IL-6, AGT, MYC, and A2M, those in the down-regulated network were IL-2, -4, and -10, MAPK8, SOCS1, and CREB1. CONCLUSION: Microarray analysis followed by gene ontology profiling and connectivity analysis identified several functional groups of genes and individual genes responding to sustained reduction of androgen levels in the mouse testis. These include genes whose products function as transcription factors, cell surface molecules including ion channels, extra- and intracellular signaling molecules, and secreted enzymes with the potential of regulating cell-to-cell attachment. The transcription factors CREB1 (down-regulated) and MYC (up-regulated) may mediate the most important initial phases of the testicular response to reduced levels of androgens. These results suggest specific avenues for further research that will lead to a better understanding of how androgens regulate spermatogenesis
Recommended from our members
Palbociclib has no clinically relevant effect on the QTc interval in patients with advanced breast cancer.
The aim of this study was to assess the potential effects of palbociclib in combination with letrozole on QTc. PALOMA-2, a phase 3, randomized, double-blind, placebo-controlled trial, compared palbociclib plus letrozole with placebo plus letrozole in postmenopausal women with estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer. The study included a QTc evaluation substudy carried out as a definitive QT interval prolongation assessment for palbociclib. Time-matched triplicate ECGs were performed at 0, 2, 4, 6, and 8 h at baseline (Day 0) and on Cycle 1 Day 14. Additional ECGs were collected from all patients for safety monitoring. The QT interval was corrected for heart rate using Fridericia's correction (QTcF), Bazett's correction (QTcB), and a study-specific correction factor (QTcS). In total, 666 patients were randomized 2 : 1 to palbociclib plus letrozole or placebo plus letrozole. Of these, 125 patients were enrolled in the QTc evaluation substudy. No patients in the palbociclib plus letrozole arm of the substudy (N=77) had a maximum postbaseline QTcS or QTcF value of ≥ 480 ms, or a maximum increase from clock time-matched baseline for QTcS or QTcF values of ≥ 60 ms. The upper bounds of the one-sided 95% confidence interval for the mean change from time-matched baseline for QTcS, QTcF, and QTcB at all time points and at steady-state Cmax following repeated administration of 125 mg palbociclib were less than 10 ms. Palbociclib, when administered with letrozole at the recommended therapeutic dosing regimen, did not prolong the QT interval to a clinically relevant extent
The Hyperdense Internal Carotid Artery Sign: Prevalence and Prognostic Relevance in Stroke Thrombolysis
Introduction. The hyperdense internal carotid artery sign (HICAS) has been suggested as a common marker of terminal internal carotid artery (ICA) thrombus associated with poor outcomes following thrombolysis. We aimed to investigate the prevalence and prognostic significance of the HICAS in an unselected cohort of patients receiving intravenous thrombolysis. Methods. Prethrombolysis NCCTs of 120 patients were examined for the presence of the HICAS and hyperdense middle cerebral artery sign (HMCAS). A poor outcome was defined as a discharge Barthel score <15 or inpatient death. Results. A HICAS was present in 3 patients (2.5%). Prethrombolysis neurological deficits were significantly more severe in patients with a HICAS (P = 0.019). HICAS was not significantly associated with a poor outcome (P = 0.323). HMCAS was significantly associated with severe prethrombolysis neurological deficits (P = 0.0025) and a poor outcome (P = 0.015). Conclusions. This study suggests that the prevalence of the HICAS may be lower than previously reported.
The presence of a HICAS was associated with severe prethrombolysis neurological deficits in keeping with terminal ICA occlusion. The role of the HICAS as a prognostic marker in stroke thrombolysis remains unclear
Colossal Magnetoresistance by Avoiding a Ferromagnetic State in the Mott System Ca3Ru2O7
Transport and magnetic studies of Ca3Ru2O7 for temperatures ranging from 0.4
K to 56 K and magnetic fields, B, up to 45 T leads to strikingly different
behavior when the field is applied along the different crystal axes. A
ferromagnetic (FM) state with full spin polarization is achieved for B||a-axis,
but colossal magnetoresistance is realized only for B||b-axis. For B||c-axis,
Shubnikov-de Haas oscillations are observed and followed by a less resistive
state than for B||a. Hence, in contrast to standard colossal magnetoresistive
materials, the FM phase is the least favorable for electron hopping. These
properties together with highly unusual spin-charge-lattice coupling near the
Mott transition (48 K) are driven by the orbital degrees of freedom.Comment: 15 pages including 3 figure
Partial antiferromagnetism in spin-chain Sr5Rh4O12, Ca5Ir3O12 and Ca4IrO6 single crystals
We report a structural, thermodynamic and transport study of the newly
synthesized Sr5Rh4O12, Ca5Ir3O12 and Ca4IrO6 single crystals. These
quasi-one-dimensional insulators consist of a triangular lattice of spin chains
running along the c-axis, and are commonly characterized by a partial
antiferromagnetic (AFM) order, a small entropy removal associated with the
phase transitions and a sizable low-temperature specific heat linearly
proportional to temperature. Sr5Rh4O12 is defined by an AFM order below 23 K
with strong evidence for an Ising character and two step-like transitions in
isothermal magnetization leading to a ferrimagnetic state at 2.4 T and a
ferromagnetic state at 4.8 T, respectively. Ca5Ir3O12 and Ca4IrO6 are also
antiferromagnetically ordered below 7.8 K and 12 K, respectively, and show an
unusually large ratio of the Curie-Weiss temperature to the Neel temperature.
In particular, Ca5Ir3O12, which includes both Ir4+ and Ir5+ ions, reveals that
only S=1/2 spins of the Ir4+ ions are involved in the magnetic ordering whereas
S=3/2 spins of the Ir5+ ions remain disordered. All results suggest the
presence of the geometrical frustration that causes incomplete long-range AFM
order in these quasi-one-dimensional compounds
In vivo tomographic imaging based on bioluminescence
The most important task for bioluminescence imaging is to identify the emission source from the captured bioluminescent signal on the surface of a small tested animal. Quantitative information on the source location, geometry and intensity serves for in-vivo monitoring of infectious diseases, tumor growth, metastases in the small animal. In this paper, we present a point-spread function-based method for reconstructing the internal bioluminescent source from the surface light output flux signal. The method is evaluated for sensing the internal emission sources in nylon phantoms and within a live mouse. The surface bioluminescent signal is taken with a highly sensitive CCD camera. The results show the feasibility and efficiency of the proposed point-spread function-based method
- …