• Title/Summary/Keyword: Positivity

Search Result 624, Processing Time 0.021 seconds

A method to analyze the flyability of airplane trajectories with specified engine power

  • Gilles Labonte;Vincent Roberge;Mohammed Tarbouchi
    • Advances in aircraft and spacecraft science
    • /
    • v.10 no.5
    • /
    • pp.473-494
    • /
    • 2023
  • This article introduces a formalism for the analysis of airplane trajectories on which the motion is determined by specifying the power of the engines. It explains a procedure to solve the equations of motion to obtain the value of the relevant flight parameters. It then enumerates the constraints that the dynamical abilities of the airplane impose on the amount of fuel used, the speed, the load factor, the lift coefficient, the positivity and upper boundedness of the power available. Examples of analysis are provided to illustrate the method proposed, with rectilinear and circular trajectories. Two very different types of airplanes are used in the examples: a Silver Fox-like small UAV and a common Cessna 182 Skylane.

PERIODIC SURFACE HOMEOMORPHISMS AND CONTACT STRUCTURES

  • Dheeraj Kulkarni;Kashyap Rajeevsarathy;Kuldeep Saha
    • Journal of the Korean Mathematical Society
    • /
    • v.61 no.1
    • /
    • pp.1-28
    • /
    • 2024
  • In this article, we associate a contact structure to the conjugacy class of a periodic surface homeomorphism, encoded by a combinatorial tuple of integers called a marked data set. In particular, we prove that infinite families of these data sets give rise to Stein fillable contact structures with associated monodromies that do not factor into products to positive Dehn twists. In addition to the above, we give explicit constructions of symplectic fillings for rational open books analogous to Mori's construction for honest open books. We also prove a sufficient condition for the Stein fillability of rational open books analogous to the positivity of monodromy for honest open books due to Giroux and Loi-Piergallini.

PREVENTION STRATEGIES TO CONTROL AN EPIDEMIC USING A SEIQHRV MODEL

  • Mohit Soni;Rajesh Kumar Sharma;Shivram Sharma
    • The Pure and Applied Mathematics
    • /
    • v.31 no.2
    • /
    • pp.131-158
    • /
    • 2024
  • This study investigates the impact of precautionary measures, such as isolating exposed individuals, wearing masks, and maintaining physical distance, on preventing infectious disease. A deterministic SEIQHRV epidemic model is employed for this purpose. The model's positivity, boundedness, disease-free, and endemic equilibrium points are identified. A sensitivity test assesses the impact of preventive measures on infected classes. Results show that a basic reproduction number less than unity drives disease eradiction, while a higher unity value encourages the adoption of preventive measures.

SPLITTING TECHNIQUE AND GODUNOV-TYPE SCHEMES FOR 2D SHALLOW WATER EQUATIONS WITH VARIABLE TOPOGRAPHY

  • Dao Huy Cuong;Mai Duc Thanh
    • Bulletin of the Korean Mathematical Society
    • /
    • v.61 no.4
    • /
    • pp.969-998
    • /
    • 2024
  • We present numerical schemes to deal with nonconservative terms in the two-dimensional shallow water equations with variable topography. Relying on the dimensional splitting technique, we construct Godunov-type schemes. Such schemes can be categorized into two classes, namely the partly and fully splitting ones, depending on how deeply the scheme employs the splitting method. An upwind scheme technique is employed for the evolution of the velocity component for the partly splitting scheme. These schemes are shown to possess interesting properties: They can preserve the positivity of the water height, and they are well-balanced.

Correlation of Proliferating Cell Nuclear Antigen (PCNA) Expression and S-phase Fraction, Survival Rate in Primary Non-Small Cell Lung Cancer (원발성 비소세포 폐암에서 PCNA의 발현정도와 암세포의 분열능 및 생존률과의 관계)

  • Yang, Sei-Hoon;Kim, Hak-Ryul;Gu, Ki-Seon;Jung, Byung-Hak;Jeong, Eun-Taik
    • Tuberculosis and Respiratory Diseases
    • /
    • v.44 no.4
    • /
    • pp.756-765
    • /
    • 1997
  • Background : To study the prognosis of patients with lung cancer, many investigators have reported the methods to detect cell proliferation in tissues including PCNA, thymidine autoradiography, flow cytometry and Ki-67. PCNA, also known as cyclin, is a cell related nuclear protein with 36KD intranuclear polypeptide that is maximally elevated in S phase of proliferating cells. In this study, PCNA was identified by paraffin-embedding tissue using immunohistochemistry which has an advantage of simplicity and maintenance of tissue architecture. The variation of PCNA expression is known to be related with proliferating fraction, histologic type, anatomic(TNM) stage, degree of cell differentiation, S-phase fraction and survival rate. We analyzed the correlation between PCNA expression and S-phase fraction, survival. Method : To investigate expression of PCNA in primary lung cancer, we used immunohistochemical stain to paraffin-embedded sections of 57 resected primary non-small cell lung cancer specimen and the results were analyzed according to the cell type, cell differentiation, TNM stage, S-phase fraction and survival. Results : PCNA expression was divided into five group according to degree of staging(-, +, ++, +++, ++++). Squamous cell type showed high positivity than in adenocarcinoma. Nonsignificant difference related to TNM stage was noticed. Nonsignificant difference related to degree of cell differentiation was noticed. S-phase fraction was increased with advance of PCNA positivity, but it could not reach the statistic significance. The 2 year survival rate and median survival time were -50% 13 months, +75% 41.3 months, ++73% 33.6 months, +++67% 29.0 months, ++++25% 9 months with statistic significance (P<0.05, Kaplan-Meier, generalized Wilcox). Conclusion : From this study, PCNA expression was high positive in squamous cell cancer. And, there was no relationship between PCNA positivity and TNM stage, cellular differentiation or S-phase fraction. But, the patients with high positive PCNA staining showed poor survival rate than the patients with lower positive PCNA staining (p<0.05). It was concluded that PCNA immunostaining is a simple and useful method for survival prediction in paraffin embedded tissue of non-small cell lung cancer.

  • PDF

Use of Human Adipose Tissue as a Source of Endothelial Cells (혈관내피세포 채취의 원천으로 인간 지방조직의 활용)

  • Park, Bong-Wook;Hah, Young-Sool;Kim, Jin-Hyun;Cho, Hee-Young;Jung, Myeong-Hee;Kim, Deok-Ryong;Kim, Uk-Kyu;Kim, Jong-Ryoul;Jang, Jung-Hui;Byun, June-Ho
    • Maxillofacial Plastic and Reconstructive Surgery
    • /
    • v.32 no.4
    • /
    • pp.299-305
    • /
    • 2010
  • Purpose: Adipose tissue is located beneath the skin, around internal organs, and in the bone marrow in humans. Its main role is to store energy in the form of fat, although it also cushions and insulates the body. Adipose tissue also has the ability to dynamically expand and shrink throughout the life of an adult. Recently, it has been shown that adipose tissue contains a population of adult multipotent mesenchymal stem cells and endothelial progenitor cells that, in cell culture conditions, have extensive proliferative capacity and are able to differentiate into several lineages, including, osteogenic, chondrogenic, endothelial cells, and myogenic lineages. Materials and Methods: This study focused on endothelial cell culture from the adipose tissue. Adipose tissues were harvested from buccal fat pad during bilateral sagittal split ramus osteotomy for surgical correction of mandibular prognathism. The tissues were treated with 0.075% type I collagenase. The samples were neutralized with DMEM/and centrifuged for 10 min at 2,400 rpm. The pellet was treated with 3 volume of RBC lysis buffer and filtered through a 100 ${\mu}m$ nylon cell strainer. The filtered cells were centrifuged for 10 min at 2,400 rpm. The cells were further cultured in the endothelial cell culture medium (EGM-2, Cambrex, Walkersville, Md., USA) supplemented with 10% fetal bovine serum, human EGF, human VEGF, human insulin-like growth factor-1, human FGF-$\beta$, heparin, ascorbic acid and hydrocortisone at a density of $1{\times}10^5$ cells/well in a 24-well plate. Low positivity of endothelial cell markers, such as CD31 and CD146, was observed during early passage of cells. Results: Increase of CD146 positivity was observed in passage 5 to 7 adipose tissue-derived cells. However, CD44, representative mesenchymal stem cell marker, was also strongly expressed. CD146 sorted adipose tissue-derived cells was cultured using immuno-magnetic beads. Magnetic labeling with 100 ${\mu}l$ microbeads per 108 cells was performed for 30 minutes at $4^{\circ}C$ a using CD146 direct cell isolation kit. Magnetic separation was carried out and a separator under a biological hood. Aliquous of CD146+ sorted cells were evaluated for purity by flow cytometry. Sorted cells were 96.04% positivity for CD146. And then tube formation was examined. These CD146 sorted adipose tissue-derived cells formed tube-like structures on Matrigel. Conclusion: These results suggest that adipose tissue-derived cells are endothelial cells. With the fabrication of the vascularized scaffold construct, novel approaches could be developed to enhance the engineered scaffold by the addition of adipose tissue-derived endothelial cells and periosteal-derived osteoblastic cells to promote bone growth.

Positive Rate of Tumor Marker according to Sites of Recurrence in Gastric Cancer (위암 재발부위에 따른 종양표지자의 양성률)

  • Jang, Jin-Seok;Lee, Sung-Wook;Lee, Jong-Hun;Roh, Myung-Hwan;Han, Sang-Young;Kim, Min-Chan;Jeong, Gap-Jung;Choi, Seok-Reyol
    • Journal of Gastric Cancer
    • /
    • v.5 no.4 s.20
    • /
    • pp.222-227
    • /
    • 2005
  • Purpose: There are several reports suggested the usefulness of serum tumor markers, AFP, CEA and CA19-9 as prognostic factors or indicators for recurrence in gastric cancer. This clinical study was peformed to evaluate positive rate of tumor markers according to site of recurrence in gastric cancer. Materials and Methods: From the database of patients who underwent radical gastrectomy for gastric cancer between January 1999 and January 2004, 52 patients who showed recurrence were included in this retrospective study. Serum levels of tumor markers were measured at the time of preoperative diagnosis of the gastric cancer and at the time of postoperative recurrence during follow up, respectively. Results: The overall positivity of tumor markers at the time of recurrence was found to be significantly higher than that of prior to surgery in the recurred group for the single test as well as the combination tests. For the peritoneum, the most common recurrent site, the positivity of CA19-9 was higher at the time of recurrence. And the significant positivity of CEA at the time of recurrence was detected in the liver cases. Conclusion: Having a preoperative positive tumor marker may identify the patient as having an increased chance of a recurrence. Although tumor markers continue to have limited diagnostic significance in gastric cancer, CA19-9 may be useful as a predictor for peritoneal recurrence of the gastric cancer, and CEA for recurrence to liver.

  • PDF

Prevalence and clinical significance of the positive antinuclear antibody in children with idiopathic thrombocytopenic purpura (소아 특발혈소판감소 자색반병 환자에서 항핵항체 검사의 양성률 및 임상적 의의)

  • Jun, So Eun;Park, Seong Sik;Lim, Young Tak
    • Clinical and Experimental Pediatrics
    • /
    • v.51 no.11
    • /
    • pp.1217-1221
    • /
    • 2008
  • Purpose : An association between idiopathic thrombocytopenic purpura (ITP) and systemic lupus erythematosus (SLE) has been recognized for decades because thrombocytopenia is the first manifestation in some patients with SLE. However, the risk of later development of SLE in childhood ITP is currently unknown. We retrospectively evaluated the incidence and clinical significance of the positive antinuclear antibody (ANA) in children with acute ITP. Methods : This study was retrospectively performed to review the clinical and laboratory characteristics in 77 children diagnosed to have acute ITP and admitted to the Pusan National University Hospital between January 2003 and December 2006. Patients tested positive for ANA were regularly followed-up for at least 12 months for symptoms indicative of SLE. Results : Seventy-seven children were included in the study; 38 males (49.4%) and 39 females (50.5%), the mean age was 4.5 years. Sixteen (20.8%) ITP patients had a positive ANA, with a median titer of 1:320. The mean age of the patients with positive ANA was 9.3 years, which is much older than 3.3 years for patients with negative ANA (P<0.05). The positive ANA group was predominantly female (81.3%) compared to the negative ANA group (P<0.05). There was no statistically significant difference in mean platelet counts between both groups. No statistically significant difference was found in ANA positivity and progression to chronic ITP or SLE. After the median follow-up of 32 months, SLE was diagnosed only in one ITP patient with positive ANA. Conclusion : Our data demonstrated that ANA positivity is often found in children with acute ITP. Large-scale studies should be considered to determine the significance of ANA positivity in childhood ITP for the later development of SLE.

Clinical Investigation of Cervical Tuberculous Lymphadenitis (결핵성 경부 임파선염의 임상적 고찰)

  • Park, Mi-Ran;Kim, Chang-Sun;Seo, Jee-Young;Son, Hyung-Dae;Rheu, Nam-Soo;Cho, Dong-Il
    • Tuberculosis and Respiratory Diseases
    • /
    • v.44 no.6
    • /
    • pp.1225-1233
    • /
    • 1997
  • Background : Cervical tuberculous lymphadenitis(CTL) is one of the most common extra-pulmonary tuberculosis. Recently overall incidence of pulmonary tuberculosis has decreased, but the incidence of tuberculous lymphadenitis has not decreased. Its duration of treatment is still controversial and the pathogenesis, prognosis and relationship with other site tuberculous are poorly published. So we did a retrograde study of 120 cases of confirmed CTL about its clinical manifestations. Method : All patients were applied fine needle aspiration(FNA) of palpable enlarged cervical lymph nodes and 114 patients were examined for AFB smear and 34 patients for TB culture with aspirated fluid. 57 patients were examined Mantoux test(5TU with PPD-S). With above methods, a total of 120 patients was diagnosed as having CTL. Results : 1) CTL is most prevalent in young women between the age of 20~30 years and the incidence of CTL in female is 2.5 times higher than that of male. It is located most commonly in the posterior cervical area. The most common presenting symptom is painless palpable enlarged cervical lymph nodes. 2) With FNA of enlarged cervical lymph nodes, the percentage of histopathological positivity is 82.3%. The percentage of AFB smear positivity is 38.6%, and that of TB culture positivity is 17.6%(p<0.001). 3) Pulmonary tuberculosis is noted in 79 cases(65.8%). And 42 cases(53.5%) of them had minimal pulmonary tuberculosis. In 14 cases(11.7%), other extrapulmonary tuberculosis coexsisted and pleural tuberculosis was most Common in the order. 4) CTL was treated with anti-tuberculous medication(first line drug) and median treatment duration was 18.5months. During treatment, the size of involved lymph nodes decreased gradually in 62 cases(75.8%), newly developed lymph nodes were found in 25 cases(30.4%), fluctuation formation in 22 cases(26.8%) and fistula formation in 14 cases(17.0%). Conclusion : CTL is prevalent in women between the age of 20~40 years and it involves posterior cervical area most commonly. CTL is treated with long-term anti-tuberculous chemotherapy. We think it is one manifestation of systemic disease and frequently coexisting with pulmonary tuberculosis. Despite anti-tuberculous chemotherapy, the size of involved lymph nodes was increased, new lymph nodes were developed or fluctuation and fistula formed in involved lymph nodes. After sufficient medication, when the patient felt pressure discomfort from enlarged lymph node or fistula was formed, we recommended total excision of involved lymph nodes.

  • PDF

Examination of Generating Mechanism Concerning Father's Participation in Child-rearing (맞벌이 가정 부친의 육아참가 발생과정)

  • Park, Ji-Sun;Kondo, Rie;Kim, Jung-Suk;Sasai, Tsukasa;Takahashi, Shigesato;Park, Chun-Man;Nakajima, Kazuo
    • Korean Journal of Health Education and Promotion
    • /
    • v.26 no.5
    • /
    • pp.57-70
    • /
    • 2009
  • Objectives: This purpose of this study was to make clear the fitness to data of the causality model related to father's child-rearing participation in a double-income household. Methods: Subjects of this survey consisted of the fathers of 2,006 households that use 21 day-care centers and 4 kindergartens whose cooperation was received via the city government departments that have jurisdiction over day-care centers and kindergartens in cities A and B in prefecture I and in city C in prefecture II (city A: 499 households; city B: 1,113 households; city C: 988 households). The surveyed items consisted of the father's age, the father's educational history, the number of children, the age of the youngest child, the father's parental-role awareness, the father's daily working hours, the father's return-home time, and child-rearing participation by the father. Results: The fit indices were found to be CFI = 0.912, GFI = 0.948, and RMSEA = 0.082. Regarding the path coefficients, the path coefficient of the pathway from the age of the youngest child to the father's parent positivity (0.08) and the path coefficient of the pathway from the father's parent positivity to child-rearing participation (0.19) were both at statistically significant levels. Also, the father's return-home time and the working hours, which were considered as disincentives exhibited a direct effect on child-rearing participation without being influenced by the father's parent positivity or parent negativity. The path coefficient of the pathway from return-home time to child-rearing participation was -0.43, and the path coefficient of the pathway from working hours to child-rearing participation was -0.13. The value of the path coefficient expressing the relationship between the return-home time and working hours was 0.80. Conclusion: Authors infered that it'll be the basic material to build a generation mechanism about vanity and father's child-rearing participation appropriately as a result of this research.