29 research outputs found

    MIMO-OFDM WDM PON with DM-VCSEL for femtocells application

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    Globalization, rapid technological changes, and growing competition not only facilitate but also make the supply chain more complex and fragile. Any disruption can disturb many organizations and even the whole system. There are many theories and frameworks that present a solution but no study is available that theoretically development framework for supply chain risk management. The focus of this study is to develop a novel framework for identifying the potential risks and assessment of their effects on supply chain performance. Additionally, evaluate the role of supply chain interaction in risk mitigation and performance improvement in Malaysian manufacturing. This is a conceptual paper, systematic as well as content analysis have been done for the literature review. For future study, there is a need to empirically verification of this theoretical framework. The proposed methodology to achieve this framework is; a questionnaire will be developed from a pool and will be validated by exploratory view for risk identification. This questionnaire will be distributed among Malaysian manufacturing and data will be analyzed through Structural Equation Modelling (SEM) for risk assessment and mitigation. The theoretical contribution of this study is support of the theory of swift, even flow as underpinning theory and information processing theory as supportive theory

    ПЭТ-КТ с 11С-метионином в диагностике анапластических астроцитом и анапластических олигодендроглиом

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    The aim of this study was to evaluate average 11C-methionine uptake for grade II (anaplastic) gliomas in a large cohort, as well as relations between MRI and PET characteristics and their unfluence on overall and progression-free survival.Materials and methods. The study was based upon 78 patients with supratentorial tumors, among them 48 with anaplastic astrocytoma (AA) and 30 with anaplastic oligodendroglioma (AO). ALL patients underwent PET-CT with 11C-methionine and MRI study (Т1, Т2, Т2-FLAIR, DWI и 3D Т1+Gd regimes). Tumor removal was performed in 71 cases, stereotactic biopsy in 8 patients. Tumor specimen were assessed by neuropatomorphologists and IDH1-status and 1p/19q co-deletion were evaluated.Study results. AA IDH− tumors demonstrated statistically significant bigger metabolic volume and radiotracer uptake comparing with AA IDH+. Moreover, AA IDH − characterized by higher fractional MET uptake. The smallest tumors (by MRI) were AOs, meanwhile their fractional contrast enhancement was higher than for AAs. AOs were also known as tumors with minimal difference between MRI and PET-CT volume. MET uptake decreased in a row АА IDH− – АОД – AA IDH+, but the difference has not reached statistical significance. For wild-type AAs metabolic volume correlated with OS and PFS, meanwhile for IDH-mutant AAs tumor volume (measured by MRI) correlated only with PFS.Conclusion. Present study based on the largest cohort of patients with anaplastic gliomas who underwent both MRI and PET with 11C-methionine. It turned out, that unlike grade II oligodendogliomas, AOs do not always demonstrate higher than their astrocytic counterparts MET uptake levels.Цель исследования: определение усредненных показателей индекса накопления (ИН) радиофармпрепарата (РФП) (11С-метионина) в группе глиом Grade III на большом клиническом материале, а также изучение взаимосвязи показателей МРТ- и ПЭТ-исследований и значений ИН РФП с показателями общей и безрецидивной выживаемости.Материал и методы. В исследуемую группу вошло 78 пациентов, из них с диагнозом анапластическая астроцитома (АА) 48 (61,5%) пациентов и анапластическая олигодендроглиома (АОД) 30 (38,5%) пациентов; во всех случаях супратенториальной локализации. Всем пациентам выполнена ПЭТ-КТ с 11С-метионином по стандартной методике, а также МРТ в режимах Т1, Т2, Т2-FLAIR, DWI и 3D Т1+Gd. В 71 случае выполнено удаление опухоли, в 8 – верификация гистологического диагноза путем стереотаксической биопсии. Все опухоли подверглись молекулярно-генетическому анализу, в том числе с исследованием мутации IDH1 и ко-делеции 1p/19q.Результаты исследования. Метаболический объем опухоли и величина ИН РФП были статистически значимо выше в группе IDH-негативных АА, нежели в группе IDH-позитивных АА; кроме того, АА дикого типа продемонстрировали более высокие значения долевого накопления РФП. Наименьший общий объем опухоли по МРТ продемонстрировали АОД, при этом долевой объем контрастирования этих опухолей был значительно выше, чем в общей группе астроцитарных опухолей; для АОД характерно минимальное отличие общего объема опухоли от метаболического. Значения ИН РФП уменьшается в ряду АА IDH− – АОД – AA IDH+, однако эти различия не достигли статистически значимых величин. В группе IDH-негативных АА объем метаболически активной ткани по данным ПЭТ демонстрировал слабоотрицательную зависимость с общей и безрецидивной выживаемостью, а объем опухоли в группе IDH-мутантных АА коррелировад только с безрецидивной выживаемостью.Заключение. Настоящая работа на крупнейшем клиническом материале анализирует соотношения результатов МРТ и ПЭТ-КТ с 11С-метионином в группе глиом Grade III. На основании полученных данных удалось продемонстрировать неоднозначность зависимости значений ИН РФП в группе анапластических глиом от наличия олигодендрокомпонента в гистоструктуре опухоли, где, в отличие от глиом Grade II, не получено значимых отличий в уровне метаболической активности астроцитарных и олигодендроглиом, обе группы демонстрировали большой разброс показателей

    Endoscopic transsphenoidal approach in the diagnosis and treatment of chiasmosellar germinomas

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    Introduction. According to the recommendations of Russian and international professional associations, treatment of germinomas can be initiated without histological verification of the diagnosis, since it can be based on biochemical tumor markers. However, patients with brain germinomas usually have normal levels of these markers; therefore, histological verification is required. Stereotactic biopsy and transcranial biopsy are sometimes associated with a risk of damage to crucial anatomical structures. Currently, both biopsy and total removal of sellar and parasellar tumors can be performed via endoscopic endonasal approach. The study objective is to demonstrate the possibility of using endoscopic transsphenoidal approach for biopsy and total removal of chiasmosellar germinomas. Materials and methods. Thirteen patients with primary chiasmosellar germinomas underwent endoscopic endonasal interventions in N. N. Burdenko National Medical Research Center for Neurosurgery between 2010 and 2017. The “Germinoma-2008” protocol was used in the subsequent treatment of these patients. The male to female ratio was 2.25 : 1; mean age was 21.1 years (6–38 years).Results. The surgery volume varied between biopsy (n = 4) and partial (n = 5) or complete (n = 4) tumor removal. The diagnosis was histologically verified in all patients. None of the patients developed liquorrhea and / or meningitis in the postoperative period, which suggests that the surgery was effective and safe. Conclusion. The endoscopic endonasal approach for histological verification of the diagnosis and removal of chiasmosellar germinomas is safe and effective
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