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검색결과 6,473건 처리시간 0.031초

Moment of Inertia of Gas as a Source of Added Gravitational Field in Galaxies

  • Portnov, Yuriy A.
    • Journal of Astronomy and Space Sciences
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    • 제39권2호
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    • pp.59-65
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    • 2022
  • In this paper we propose a new perspective for explaining galaxy rotation curves. We conjecture that there is a gravitational moment of inertia which, together with gravitational mass, contributes to the gravitational potential. We substantiate a formula for the potential created by the moment of inertia. We validate our model by computing orbital rotation velocities for several galaxies and showing that computed rotation velocities correspond to the observed ones. Our proposed approach is capable of accounting for constant gas velocities outside of a galactic disc without relying on the dark matter hypothesis. Furthermore, it addresses several problems faced by the application of the dark matter hypothesis, e.g., the absence of inward collapse of dark matter into a galaxy, the spherical distribution of dark matter around galaxies, and absence of traces of the effect of dark matter in two ultra-diffuse galaxies, NGC 1052-DF2, and NGC 1052-DF4.

Appendiceal Mucinous Neoplasm Detected due to the Protrusion of Mucin, in the Absence of Appendiceal Distension: A Case Report

  • Park, Jin Woo;Park, Min Geun;Song, Ji-Sun;Cho, Hyeon Je;Kim, Yu Jin
    • Journal of Digestive Cancer Reports
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    • 제8권2호
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    • pp.109-111
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    • 2020
  • A mucocele is a cystic dilatation of the vermiform appendix that contains mucous material. The symptoms associated with it are not specific and the diagnosis is seldom made prior to surgery. The reported prevalence in appendectomy specimens procured during surgery is 0.2-0.3%. Recently, we experienced a case of patient with appendiceal mucocele detected by colonoscopic examination. This case did not show typical colonoscopic features of a mucocele, demonstrating protrusion of mucin, in the absence of a smooth mound with normal overlying mucosa surrounding the appendiceal orifice. The case involved a 64-year-old woman who underwent a colonoscopy. An abdominopelvic computed tomography scan suggested a normal appendix. Subsequently, we performed an appendectomy. The pathologic finding was a low-grade appendiceal mucinous neoplasm.

AN INNOVATION DIFFUSION MODEL IN PARTIAL COMPETITIVE AND COOPERATIVE MARKET: ANALYSIS WITH TWO INNOVATIONS

  • CHUGH, S.;GUHA, R.K.;DHAR, JOYDIP
    • Journal of Applied and Pure Mathematics
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    • 제4권1_2호
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    • pp.27-36
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    • 2022
  • An innovation diffusion model is proposed model consists of three classes, namely, a non-adopter class, adopter class innovation-I, and adopter class innovation-II in a partially competitive and cooperative market. The proposed model is analyzed with the help of the qualitative theory of a system of ordinary differential equations. Basic influence numbers associated with first and second innovation $R_{0_1}$ and $R_{0_2}$ respectively in the absence of each other are quantified. Then the overall basic influence number (R0) of the system is assessed for analyzing stability in the market in different situations. Sensitivity analysis of basic influence numbers associated with first and second innovation in the absence of each other is carried out. Numerical simulation supports our analytical findings.

Biomarker-directed Targeted Therapy in Colorectal Cancer

  • John M. Carethers
    • Journal of Digestive Cancer Research
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    • 제3권1호
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    • pp.5-10
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    • 2015
  • With advances in the understanding of the biology and genetics of colorectal cancer (CRC), diagnostic biomarkers that may predict the existence or future presence of cancer or a hereditary condition, and prognostic and treatment biomarkers that may direct the approach to therapy have been developed. Biomarkers can be ascertained and assayed from any tissue that may demonstrate the diagnostic or prognostic value, including from blood cells, epithelial cells via buccal swab, fresh or archival cancer tissue, as well as from cells shed into fecal material. For CRC, current examples of biomarkers for screening and surveillance include germline testing for suspected hereditary CRC syndromes, and stool DNA tests for screening average at-risk patients. Molecular biomarkers for CRC that may alter patient care and treatment include the presence or absence of microsatellite instability, the presence or absence of mutant KRAS, BRAF or PIK3CA, and the level of expression of 15-PGDH in the colorectal mucosa. Molecularly targeted therapies and some general therapeutic approaches rely on biomarker information. Additional novel biomarkers are on the horizon that will undoubtedly further the approach to precision or individualized medicine.

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Ontogenetic variation in Chironomus flaviplumus (Diptera, Chironomidae) larvae

  • Hyunsu Yoo;Jae-won Park;Ihn-Sil Kwak
    • Journal of Species Research
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    • 제13권1호
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    • pp.41-49
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    • 2024
  • Chironomus is a large genus of Diptera comprising about 400 species and occurs worldwide except for Antarctica. The strong morphological cross-taxon similarity of chironomid larvae renders identification at the species level difficult. Here, we analyzed the morphology of larvae of Chironomus flaviplumus, an easily cultured species employed as a bioindicator in polluted environments, to determine identifying morphological characteristics at the first through fourth instar. Observed differences appearing at each instar include the presence or absence of setae on the body and tubules on the 10th and 11th body segment, the number of seta interna in the mandible, and the presence or absence of ring organs in the antennae. Some specific morphological characteristics did not change after hatching. Our findings provide a reliable method for identifying C. flaviplumus larvae.

Ultrasound Utility for Predicting Biological Behavior of Invasive Ductal Breast Cancers

  • Zhang, Lei;Liu, Yu-Jie;Jiang, Shuang-Quan;Cui, Hao;Li, Zi-Yao;Tian, Jia-Wei
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권19호
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    • pp.8057-8062
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    • 2014
  • Purpose: The aim of the study was to evaluate the correlation of ultrasound features with breast cancer molecular status. Materials and Methods: A retrospective review was performed of ultrasound findings in 263 patients diagnosed with breast invasive ductal carcinoma for comparison with immunohistochemistric results were obtained from each lesion. Relationships between ultrasound findings and molecular status were investigated by using multiple regression analysis by means of stepwise logistic regression. Differences in ultrasound criteria were assessed among women with different molecular status. Results: ER positivity was associated with small size, lobulate, angular or spiculated margin contours, absence of calcification, posterior tumor shadowing and low elasticity score; PR positivity was associated with small size, lobulate or angular or spiculated margin contours and absence of calcification; HER2 positivity was associated with presence of calcification and absence of any echogenic halo. The calculated models of predicted molecular status were accurate and discriminating with AUCs of 0.78, 0.74, and 0.74, respectively. Conclusions: Breast cnacer ultrasound features show some correlation with the molecular status. These models may help to expand the scope of ultrasound in predicting tumor biology.

가토 척출 자궁근의 운동성에 관한 연구 V. Acetylcholine, PGF2α 및 Oxytocin의 자궁 수축기전에 관한 연구 (Studies on the Mechanical Activities of Rabbit Myometrium V. Effects of Acetylcholine, Oxytocin and Prostagla, din F2α on Cyclic Nucleotide Levels of Rabbit Whole Uterus)

  • 이창업;권종국;이준섭;양일석;이문한
    • 대한수의학회지
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    • 제22권1호
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    • pp.1-8
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    • 1982
  • The effect of acetylcholine, oxytocin and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) on cyclic nucleotide levels in estrogen-primed rabbit whole uterus were studied in the presence and absence of 1-methyl-3-isobutyl xanthine (MIX), a phosphodiestrase inhibitor, and indomethacin, a prostagandin inhibitor. In the absence of MIX, acetylcholine increased guanosine 3', 5'-cyclic monophosphate (cGMP), but had no effect on adenosine 3', 5'-cyclic monophosphate (cAMP) levels. In contrast, oxytocin had no influence on cGMP, but decreased cAMP levels. $PGF_{2{\alpha}}$ increased cGMP and decreased cAMP levels. MIX increased both cAMP and cGMP levels. Oxytocin and $PGF_{2{\alpha}}$ further increased cGMP levels, indicating activation of guanylate cyclase activity. The ratio of cAMP/cGMP was decreased by uterine stinulants both in presence and absence of MIX. Indomethacin elevated cAMP and cGMP revels. The effects of uterine stimulants in the presence of indomethacin on cyclic nucleotide levels were varied from tissue to tisse. In general, oxytocin decreased cGMP and $PGF_{2{\alpha}}$ increased cAMP/cGMP levels, but the effects were statisically nonsignicficant. The cAMP/cGMP ratio was increased by uterine stimulant in the presence of indomethacin. In conclusion, uterine stimulants eased cAMP/cGMP ratio which indicates that the uterine stimulants have opposing effects on adenylate cyclase and guanylate cyclase activities. The endometrium plays a role in the regulation of cyclic nucleotide levels and uterine contraction by means of PG synthesis. Indomethacin has an unknown activities besides both of PG synthetase and phosphodiesterase inhibitions.

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