• Title/Summary/Keyword: Positivity

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Stability and Optimal Harvesting in Lotka-Volterra Competition Model for Two-species with Stage Structure

  • Al-Omari, J.F.M.
    • Kyungpook Mathematical Journal
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    • v.47 no.1
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    • pp.31-56
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    • 2007
  • In this paper, we consider a delay differential equation model of two competing species with harvesting of the mature and immature members of each species. The time delay in the model represents the time from birth to maturity of that species, which appears in the adults recruitment terms. We study the dynamics of our model analytically and we present results on positivity and boundedness of the solution, conditions for the existence and globally asymptotically stable of equilibria, a threshold of harvesting, and the optimal harvesting of the mature populations of each species.

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Cytologic Findings of Cerebrospinal Fluid (뇌척수액의 세포병리)

  • Jin, So-Young
    • The Korean Journal of Cytopathology
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    • v.19 no.2
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    • pp.86-98
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    • 2008
  • Cerebrospinal fluid (CSF) cytology is based on the cytopathologic findings of other body fluids. However, CSF's cytologic features are less familiar to physicians than are those of the other body fluid's cytology because of the small number of cases. The low overall diagnostic accuracy and the presence of false positivity still remain as problems. The incidence of lymphoreticular malignancies and metastatic carcinomas are rather higher than that of primary brain tumors. In this review, the characteristic cytologic findings of conventional CSF cytology are reviewed along with a brief note on the technical preparation and diagnostic pitfalls.

The Region of Positivity and Unimodality in the Truncated Series of a Nonparametric Kernel Density Estimator

  • Gupta, A.K.;Im, B.K.K.
    • Journal of the Korean Statistical Society
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    • v.10
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    • pp.140-144
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    • 1981
  • This paper approximates to a kernel density estimate by a truncated series of expansion involving Hermite polynomials, since this could ease the computing burden involved in the kernel-based density estimation. However, this truncated series may give a multimodal estimate when we are estiamting unimodal density. In this paper we will show a way to insure the truncated series to be positive and unimodal so that the approximation to a kernel density estimator would be maeningful.

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On the Paneitz-Branson Operator in Manifolds with Negative Yamabe Constant

  • Ali, Zouaoui
    • Kyungpook Mathematical Journal
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    • v.62 no.4
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    • pp.751-767
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    • 2022
  • This paper deals with the Paneitz-Branson operator in compact Riemannian manifolds with negative Yamabe invariant. We start off by providing a new criterion for the positivity of the Paneitz-Branson operator when the Yamabe invariant of the manifold is negative. Another result stated in this paper is about the existence of a metric on a manifold of dimension 5 such that the Paneitz-Branson operator has multiple negative eigenvalues. Finally, we provide new inequalities related to the upper bound of the mean value of the Q-curvature.

Triple Negative Breast Cancer in People of North East India: Critical Insights Gained at a Regional Cancer Centre

  • Sharma, Mousumi;Sharma, Jagannath Dev;Sarma, Anupam;Ahmed, Shiraj;Kataki, Amal Chandra;Saxena, Rahul;Sharma, Dilutpal
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.11
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    • pp.4507-4511
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    • 2014
  • Background: Breast cancer is a heterogeneous disease comprising of distinct biological subtypes with many targeted prognostic biomarkers having therapeutic implications. However, no specific targeted therapy for triple negative breast cancer has been discovered to date and hence further research is needed. Aim: The aim and objectives of the present study were to examine the prevalence of triple negative breast cancer (TNBC) in North-East India and to compare the clinicopathological parameters in two study groups defined by immunohistochemistry (IHC) - "TNBC" and "Others". Materials and Methods: We carried out a retrospective study in a cohort of 972 patients diagnosed with invasive breast carcinoma in the Department of Pathology, Dr. B. Borooah Cancer Institute, a Regional Cancer Centre for treatment and research, Guwahati, for a period of 3 years and 10 months from January 2010 to October 2013. Based on IHC findings, patients were divided into two groups - "TNBC" and "Others". All relevant clinicopathological parameters were compared in both. TNBC were defined as those that were estrogen receptor (ER), progesterone receptor (PR), and HER2/neu negative while those positive for any of these markers were defined as "Others". Results: In this study, out of total 972 cases 31.9% (310 cases) were defined as TNBC and 662 cases (68.1%) as "Others" based on IHC markers. Compared to the "Others" category, TNBC presented at an early age (mean 40 years), were associated with high grade large tumours and high rate of node positivity, IDC NOS being the most common histological subtype in TNBC. Conclusions: TNBC accounts for a significant portion of breast cancers in this part of India and commonly present at younger age and tend to be large high grade tumours.

Determination of Frequency of Epstein-Barr Virus in Non-Hodgkin Lymphomas Using EBV Latent Membrane Protein 1 (EBV-LMP1) Immunohistochemical Staining

  • Ishtiaq, Sheeba;Hassan, Usman;Mushtaq, Sajid;Akhtar, Noreen
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.6
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    • pp.3963-3967
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    • 2013
  • Background: The presence of Epstein-Barr virus (EBV) in Non-Hodgkin's lymphoma can be identified by immunohistochemistry for detection of EBV latent membrane protein (LMP). The role of EBV as an etiologic agent in the development of non-Hodgkin lymphoma has been supported by detection of high levels of latent membrane protein 1 (LMP-1) expression in tumors. However, no study has been conducted in a Pakistani population up till now to determine the frequency of Epstein-Barr virus positivity. The objective of our study was to determine a value for non-Hodgkin lymphoma patients using EBV LMP-1 immunostaining in our institution. Materials and Methods: This study was carried out at the Department of Histopathology, Armed Forces Institute of Pathology (AFIP), Pakistan from December 2011 to December 2012. It was a cross sectional study. A total of 71 patients who were diagnosed with various subtypes of NHL after histological and EBV LMP-1 immunohistochemical evaluation were studied. Sampling technique was non-probability purposive. Statistical analysis was achieved using SPSS version 17.0. Mean and SD were calculated for quantitative variables like patient age. Frequencies and percentages were calculated for qualitative variables like subgroup of NHL, results outcome of IHC for EBV and gender distribution. Results: Mean age of the patients was $53.6{\pm}16$ years (Mean${\pm}$SD). A total of 50 (70.4%) were male and 21 (29.6%) were female. Some 9 (12.7%) out of 71 cases were positive for EBV-LMP-1 immunostaining, 2 (22.2%) follicular lymphoma cases, 1 (11.1%) case of T-cell lymphoblastic lymphoma, 4 (44.4%) cases of diffuse large B cell lymphomas, 1 (11.1%) mantle cell lymphoma and 1 (11.1%) angioimmunoblastic T cell lymphoma case. Conclusion: In our study, frequency of EBV in NHL is 12.7% and is mostly seen in diffuse large B cell lymphoma. This requires further evaluation to find out whether this positivity is due to co-infection or has a role in pathogenesis.

Correlation Between Skin Prick Test and Enzyme-linked Immunosorbent Assay Using Serum for Identification of Subjects Positive to Major Indoor Respiratory Allergens (실내환경 주요 호흡기 알레르기 항원 감작검사를 위한 피부단자 시험과 혈청 ELISA시험의 상관성에 대한 연구)

  • Heo, Yong;Kim, Hyoung-Ah
    • Journal of Environmental Health Sciences
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    • v.34 no.5
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    • pp.369-373
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    • 2008
  • The indoor environment is an important source of exposure to various aeroallergens and pathogenic microorganism. It has been shown that exposure to aeroallergens enhances the risk of indoor inhabitants developing asthma. Since the skin prick test, a typical clinical method for identification of subjects positive to allergens, can rarely cause fatal or non-fatal reactions in susceptible persons, an in vitro assay such as ELISA using serum has been considered for testing positivity against various allergens. We evaluated the validity of a serum ELISA kit for screening positive subjects to major aeroallergens including Dermatophagoides farinae, Dermatophagoides pteronyssinus, cockroach, Alternaria, Cladosporium, Aspergillus, Penicillium, dog hair, cat fur, mugwort, and ragweed. The ELISA results were compared with the skin prick test results, and sensitivity, specificity, and overall accuracy were calculated to each allergen. Higher sensitivities were obtained from D. farinae, (77.8%) and D. pteronyssinus (69.2%), but sensitivities to Aspergillus, Penicillium, dog hair, cat fur, and ragweed were very low down to 0%. Specificity ranged from 88.7% (cat fur) to 100% (mugwort and ragweed). Overall the accuracy of the serum ELISA kit was relatively high, in that the lowest was 85.1% for cat fur and the highest was 98.6% for Alternaria, Cladosporium, and ragweed. Considering specificity and overall accuracy for the serum ELISA kit, it may be considered reliable. However, when the kit is used for screening purpose, positivity to aeroallergens should be carefully determined since sensitivity for the kit is low.

p53 Immunoreactivity in the Cytology of Body Cavity Fluid (체강 삼출액의 세포학적 검사에서의 p53 면역염색의 유용성)

  • Sung, Sun-Hee;Han, Woon-Sup
    • The Korean Journal of Cytopathology
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    • v.9 no.1
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    • pp.15-20
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    • 1998
  • Mutant form of the p53 gene product is abnormally accumulated in the nuclei of the tumor cells due to prolonged half life, and readily detected by immunohistochemical methods. To determine the positivity rate of p53 in body cavity fluid according the primary site and histological types of tumors and the utility of p53 immunostaining as an adjunct in the diagnosis of malignancy, we reviewed 69 effusions, including pleural effusion, ascitic fluid, and pericardial fluid, that were diagnosed as overt malignancy and 21 effusions of suspicious malignancy, immunohistochemistry was performed on paraffin-embedded cell blocks using a monoclonal antibody to p53 supressor gene product(Clone DO7) and a standard avidin-biotin complex technique with a citrate buffer antigen retrieval solution. The results were as follows; of the 46 pleural effusions with overt malignancy, 22 were immunopositive for p53 protein; of the 21 ascitic fluids with overt malignancy, 5 were positive for p53. Positivity rates according to the primary sites of tumors were 18 of 34(52.9%), 8 of 21(38.1%), 1 of 9(11.1%) cases of the tumors of the lung, GI tract, and ovary, respectively. According to the histologic types of lung cancer, 11 cases(61.6%) were positive out of 18 adenocarcinomas, 2 of 5 large cell undifferentiated carcinomas, and 1 of 2 small cell undifferentiated carcinomas. Of 21 cases of suspicious malignancy, 6 were positive for p53 and all of them(6/6) were confirmed as adenocarcinoma of the lung or GI tract. These findings indicate that p53 immunostaining using paraffin embedded cell block is useful diagnostic and prognostic marker in body fluid cytology although negative immunostaining does not exclude malignancy.

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The Influence of Psychological Well-being on Spiritual Well-being: Mediating Effets of Resilience and Social Support (목회자 사모의 심리적 안녕감이 영적 안녕감에 미치는 영향: 회복탄력성과 사회적 지지의 매개효과)

  • Kim, Nami
    • The Journal of the Korea Contents Association
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    • v.16 no.2
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    • pp.673-685
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    • 2016
  • This study investigated the mediating effects of resilience and social support on the association between psychological and spiritual well-being. The survey findings and resulting analysis of the 236 participants measured their psychological well-being, spiritual well-being, resilience, and social support follow: First, psychological well-being, resilience, and social support showed a positive correlation with spiritual well-being. Resilience shows high correlations with psychological and spiritual well-being. Second, the relationship between psychological and spiritual well-being was partially mediated by resilience, but was not mediated by social support. Lastly, the influence of resilience sub factors(self control capability, interpersonal relationship ability, positivity) on spiritual well-being shows that positivity was highly significant. Finally, this study discusses educational implications for increasing spiritual well-being for pastors' wives.

Helicobacter pylori babA2 Positivity Predicts Risk of Gastric Cancer in Ardabil, a Very High-Risk Area in Iran

  • Abdi, Esmat;Latifi-Navid, Saeid;Yazdanbod, Abbas;Zahri, Saber
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.2
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    • pp.733-738
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    • 2016
  • Background: Ardabil, a Northwestern province of Iran, was found to have the highest rate of gastric cancer (GC) in the country (ASRs = 51.8/100,000 for males and 24.9/100,000 for females) and one of the highest gastric cardia cancer rates in the world. The aim of the present study was to assess the associations of the cagA and babA2 status of Helicobacter pylori with GC in the Ardabil population. Materials and Methods: A total of 103 patients with non-atrophic gastritis (56) and GC (47), who underwent endoscopy at the Imam Khomeini Hospital in Ardabil, were assessed. The status of 16S rDNA, cagA and babA2 genes was determined using PCR and histopathological assessment was performed. Results: The following genotypic frequency was observed: cagA+ (50.6%), cagA-(49.4%), babA2+ (26.5%), babA2- (73.5%) cagA+/babA2+ (19.3%), cagA-/babA2+ (7.2%), cagA+/babA2-(31.3%), cagA-/babA2-(42.2%). Although the frequency of the cagA+, cagA+/babA2+ and cagA-/babA2+ genotypes in patients with GC (55.6%, 25.9%, and 14.8%, respectively) was higher than in those with NAG (48.2%, 16.1%, and 3.6%, respectively), the difference did not reach significance. In contrast, the presence of the babA2 gene (40.7% vs 19.6%) significantly increased the risk of GC; the age-sex-adjusted odds ratio (95% confidence interval) was 5.068 (1.506-17.058; P=0.009), by multiple logistic regression. Conclusions: It is proposed that the H. pylori babA2 positivity might be considered as an important determinant of GC risk in Ardabil.