47 research outputs found

    A solution for galactic disks with Yukawian gravitational potential

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    We present a new solution for the rotation curves of galactic disks with gravitational potential of the Yukawa type. We follow the technique employed by Toomre in 1963 in the study of galactic disks in the Newtonian theory. This new solution allows an easy comparison between the Newtonian solution and the Yukawian one. Therefore, constraints on the parameters of theories of gravitation can be imposed, which in the weak field limit reduce to Yukawian potentials. We then apply our formulae to the study of rotation curves for a zero-thickness exponential disk and compare it with the Newtonian case studied by Freeman in 1970. As an application of the mathematical tool developed here, we show that in any theory of gravity with a massive graviton (this means a gravitational potential of the Yukawa type), a strong limit can be imposed on the mass (m_g) of this particle. For example, in order to obtain a galactic disk with a scale length of b ~ 10 kpc, we should have a massive graviton of m_g << 10^{-59} g. This result is much more restrictive than those inferred from solar system observations.Comment: 7 pages; 1 eps figure; to appear in General Relativity and Gravitatio

    [Trophoblastic diseases]

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    Item does not contain fulltextHydatidiform mole is the most frequently-occurring gestational trophoblastic disease (GTD). Patients with GTD have elevated human chorionic gonadotrophin (HCG) produced by the trophoblast. After evacuation of the mole, weekly serum HCG determinations can be used to assess whether the trophoblast is persisting or regressing based on the standardised normal Nijmegen serum HCG regression curve. The serum HCG pattern is used to establish the diagnosis 'persistent trophoblastic disease'. Treatment with monochemotherapy in the form of methotrexate is the treatment of choice. For about 80% of women with a persistent trophoblastic disease following a molar pregnancy this treatment will lead to a complete remission of the disorder. If resistance to methotrexate occurs then a combined therapy is indicated. A recently developed, and as yet unvalidated, normogram for the serum HCG level during methotrexate treatment might in the near future be able to identify patients with methotrexate resistance at an early stage. Hysterectomy or curettage may be indicated as part of therapy in selected patients. The incidence of choriocarcinoma after a live birth is estimated at 1 in every 40,000 full-term pregnancies. These patients have a high risk for resistance to methotrexate (75%). Treatment of these patients with primary combination therapy at a specialised medical centre is then indicated

    DESA1002 'Continuous City' Niki Gango

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    The Continuous City has been the underlying theme throughout the semester and as such requires a little attention when interpreting the conglomeration of projects that encompass not only Tunis but the wider context. Cities such as Dubrovnik, Madrid, Isfahan, Tokyo, Amsterdam, Venice, Paris, Stockholm, New York and Jerusalem all formed part of the Continuous City and each student was given a section of their respective city that would ultimately become the basis of their work throughout the semester. The objective of this project was to realize a design concept based on the site F13 in Tunis. The approach undertaken towards this project was to delve into the local traditional housing of Tunis. Ultimately this would lead to the discovery of the quintessential Tunisian courtyard that played a significant role throughout the design process. When designing for an urban dwelling such as a set of three apartments as was proposed throughout my project the consideration of the courtyard: internal, external, shared or otherwise would became an integral facet to the development of the site. Further investigation into Tunisian housing culture also resulted in the understanding that there exists a strong push in Tunis back towards traditional housing methods. Some of the features that persist in such methods include the limited palette of exterior openings, with the incorporation of mainly interior openings that surround the typical Tunisian courtyard space. Furthermore, access to living areas, bedrooms and kitchen areas designed around such a centralised courtyard in order to facilitate local living traditions became of significance. As well as the adoption of thick exterior walls to ward off the harsh African sun. Thus my approach was to design with Tunisian living in mind. In particular special consideration was given to the appropriation of room sizes very early on in the design process. This became the basis for the apartments in addition to the tweaking of the apartment layout and functionality prior to the later adoption of a shaded public space that would sit below the apartments

    Sentinel node dissection is safe in the treatment of early-stage vulvar cancer.

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    Contains fulltext : 71041.pdf (publisher's version ) (Open Access)PURPOSE: To investigate the safety and clinical utility of the sentinel node procedure in early-stage vulvar cancer patients. PATIENTS AND METHODS: A multicenter observational study on sentinel node detection using radioactive tracer and blue dye was performed in patients with T1/2 (< 4 cm) squamous cell cancer of the vulva. When the sentinel node was found to be negative at pathologic ultrastaging, inguinofemoral lymphadenectomy was omitted, and the patient was observed with follow-up for 2 years at intervals of every 2 months. Stopping rules were defined for the occurrence of groin recurrences. RESULTS: From March 2000 until June 2006, a sentinel node procedure was performed in 623 groins of 403 assessable patients. In 259 patients with unifocal vulvar disease and a negative sentinel node (median follow-up time, 35 months), six groin recurrences were diagnosed (2.3%; 95% CI, 0.6% to 5%), and 3-year survival rate was 97% (95% CI, 91% to 99%). Short-term morbidity was decreased in patients after sentinel node dissection only when compared with patients with a positive sentinel node who underwent inguinofemoral lymphadenectomy (wound breakdown in groin: 11.7% v 34.0%, respectively; P < .0001; and cellulitis: 4.5% v 21.3%, respectively; P < .0001). Long-term morbidity also was less frequently observed after removal of only the sentinel node compared with sentinel node removal and inguinofemoral lymphadenectomy (recurrent erysipelas: 0.4% v 16.2%, respectively; P < .0001; and lymphedema of the legs: 1.9% v 25.2%, respectively; P < .0001). CONCLUSION: In early-stage vulvar cancer patients with a negative sentinel node, the groin recurrence rate is low, survival is excellent, and treatment-related morbidity is minimal. We suggest that sentinel node dissection, performed by a quality-controlled multidisciplinary team, should be part of the standard treatment in selected patients with early-stage vulvar cancer

    BRCA1 and p53 protein expression in cultured ovarian surface epithelial cells derived from women with and without a BRCA1 germline mutation.

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    Item does not contain fulltextAIM: Mutations in the BRCA1 and TP53 genes are early genetic events leading to (hereditary) ovarian carcinoma. The human ovarian surface epithelium (OSE) is considered the tissue of origin of at least a subset of these tumours. Therefore, OSE cell cultures derived from women harbouring BRCA1 germline mutations can be a potential model to study hereditary ovarian carcinogenesis. In fact, previous in vitro studies indicate phenotypical differences between OSE from women with and without such germline mutations. Therefore, we have assessed whether differences in the expression of BRCA1 and p53 proteins in cultured OSE cells could contribute to these observations. STUDY DESIGN: Thirty-two OSE cultures derived from women harbouring a BRCA1 mutation (Predisposed OSE [POSE]) and ten cultures from women without a cancer predisposition (Non predisposed OSE [NPOSE]) were grown under standard conditions. Immunocytochemistry was performed to assess the expression of the BRCA1- and p53 proteins. Ki67 immunocytochemical expression was assessed to determine possible differences in cell cycle status between the two groups. In addition, to study whether wild type p53 was expressed, induction of p53 by cis-platinum was assessed by Western blot. RESULTS: On the basis of Ki67 expression, three different groups were analyzed. In the group with all cultures that expressed Ki67 no significant difference was observed in BRCA1 (P = 0.19) and p53 expression (P = 0.09). In the group with moderate to high Ki67 expression no difference in BRCA1 expression (P = 0.50) was observed. However, p53 expression was significantly lower in the case group (P = 0.01). The same observation for p53 was made in the group with only high Ki67 expression (P = 0.02). Furthermore, the expression of both BRCA1 and p53 positively correlates with Ki67 expression. In POSE and NPOSE, p53 was induced by cis-platinum to a similar extent. CONCLUSION: Our study indicates differences in the expression of p53, but not in the expression of BRCA1 between POSE and NPOSE. In addition, our findings do suggest the absence of losses of the wild type BRCA1 and p53 genes in the studied OSE cultures. This indicates that losses in these genes cannot account for observed differences in phenotypical traits between POSE and NPOSE, but that differences in levels of p53 might contribute

    Vaginal Radical Trachelectomy for Early-Stage Cervical Cancer: Increased Recurrence Risk for Adenocarcinoma

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    OBJECTIVE: To evaluate consecutive vaginal radical trachelectomies (VRTs) in early-stage cervical cancer in the 2 main referral centers for fertility-preserving surgery in the Netherlands. MATERIALS AND METHODS: Oncology, fertility, and obstetrical data were recorded in a regional database of all VRTs without neoadjuvant chemotherapy performed in 2 major referral centers between 2000 and 2015. RESULTS: Most of the patients (91.7%) had stage IB1 disease. In 72.0%, squamous cell carcinoma was the histologic diagnosis; in 24.2%, adenocarcinoma; and in 3.8%, adenosquamous carcinoma. The median follow-up was 51 months.Nine (6.8%) recurrences occurred, 4 resulting in death of disease (death rate, 3.0%). Recurrence rates were 12.5% for adenocarcinoma, 20% for adenosquamous carcinoma, and 4.2% for squamous cell carcinoma (P < 0.01).From 117 women, data about fertility and obstetrical outcome were obtained. Almost 60% of women attempted to conceive after a VRT. Of these women, 40% needed fertility treatment. A total of 47 pregnancies were established, and a total of 37 children were born of which 30 (81.1%) were delivered after 32 weeks of gestational age. CONCLUSIONS: Nonsquamous cell histology and high-grade disease are associated with a significantly higher risk of recurrence in the univariate and multivariate analyses. Women with both these histology features should be counseled reticently for VRT.Pregnancies after VRT must be regarded as high-risk pregnancies with a high prematurity rate
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