261 research outputs found
Homological smoothness and deformations of generalized Weyl algebras
It is an immediate conclusion from Bavula's papers \cite{Bavula:GWA-def},
\cite{Bavula:GWA-tensor-product} that if a generalized Weyl algebra
A=\kk[z;\lambda,\eta,\varphi(z)] is homologically smooth, then the polynomial
has no multiple roots. We prove in this paper that the converse is
also true. Moreover, formal deformations of are studied when \kk is of
characteristic zero.Comment: Final version, 36 page
Non-commutative deformations and quasi-coherent modules
We identify a class of "quasi-compact semi-separated" (qcss) twisted
presheaves of algebras A for which well-behaved Grothendieck abelian categories
of quasi-coherent modules Qch(A) are defined. This class is stable under
algebraic deformation, giving rise to a 1-1 correspondence between algebraic
deformations of A and abelian deformations of Qch(A). For a qcss presheaf A, we
use the Gerstenhaber-Schack (GS) complex to explicitely parameterize the first
order deformations. For a twisted presheaf A with central twists, we descibe an
alternative category QPr(A) of quasi-coherent presheaves which is equivalent to
Qch(A), leading to an alternative, equivalent association of abelian
deformations to GS cocycles of qcss presheaves of commutative algebras. Our
construction applies to the restriction O of the structure sheaf of a scheme X
to a finite semi-separating open affine cover (for which we have an equivalence
between Qch(O) and Qch(X)). Under a natural identification of
Gerstenhaber-Schack cohomology of O and Hochschild cohomology of X, our
construction is shown to be equivalent to Toda's construction in the smooth
case
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Deterministic Separation of Cancer Cells from Blood at 10 mL/min
Circulating tumor cells (CTCs) and circulating clusters of cancer and stromal cells have been identified in the blood of patients with malignant cancer and can be used as a diagnostic for disease severity, assess the efficacy of different treatment strategies and possibly determine the eventual location of metastatic invasions for possible treatment. There is thus a critical need to isolate, propagate and characterize viable CTCs and clusters. Here, we present a microfluidic device for mL/min flow rate, continuous-flow capture of viable CTCs from blood using deterministic lateral displacement arrays. We show here that a deterministic bump array can be designed such that it will isolate with efficiency greater than 85% CTCs over a large range in sizes from millimeter volume clinical blood samples in minutes, with no effect on cell vitality so that further culturing and analysis of the cells can be carried out
Modeling Three-dimensional Invasive Solid Tumor Growth in Heterogeneous Microenvironment under Chemotherapy
A systematic understanding of the evolution and growth dynamics of invasive
solid tumors in response to different chemotherapy strategies is crucial for
the development of individually optimized oncotherapy. Here, we develop a
hybrid three-dimensional (3D) computational model that integrates
pharmacokinetic model, continuum diffusion-reaction model and discrete cell
automaton model to investigate 3D invasive solid tumor growth in heterogeneous
microenvironment under chemotherapy. Specifically, we consider the effects of
heterogeneous environment on drug diffusion, tumor growth, invasion and the
drug-tumor interaction on individual cell level. We employ the hybrid model to
investigate the evolution and growth dynamics of avascular invasive solid
tumors under different chemotherapy strategies. Our simulations reproduce the
well-established observation that constant dosing is generally more effective
in suppressing primary tumor growth than periodic dosing, due to the resulting
continuous high drug concentration. In highly heterogeneous microenvironment,
the malignancy of the tumor is significantly enhanced, leading to inefficiency
of chemotherapies. The effects of geometrically-confined microenvironment and
non-uniform drug dosing are also investigated. Our computational model, when
supplemented with sufficient clinical data, could eventually lead to the
development of efficient in silico tools for prognosis and treatment strategy
optimization.Comment: 41 pages, 8 figure
Аванпроєкт пасажирського дальньо-магістрального літака місткістю 240 пасажирів
Робота публікується згідно наказу Ректора НАУ від 27.05.2021 р. №311/од "Про розміщення кваліфікаційних робіт здобувачів вищої освіти в репозиторії університету". Керівник роботи: професор, д.т.н. Карускевич Михайло ВіталійовичThis diploma work is dedicated to preliminary design of the long-range passenger aircraft with 240 passengers capacity and its design characteristic estimation. The work considers comparative analyze of the planes-prototypes and selection of the most advanced technical decisions for wing, fuselage, tail unit, landing gear, high lift devices, primary flight control surfaces. For the acceptable range of center of gravity position the iterative method for the units mass location have been used. The diploma work contains preliminary design of the Roller Module for cargo hold and container compartment in the special part.Дана дипломна робота присвячена ескізному проекту далекомагістрального пасажирського літака місткістю 240 пасажирів та оцінці його конструктивних характеристик. У роботі розглянуто порівняльний аналіз літаків-прототипів і вибір найбільш прогресивних технічних рішень крила, фюзеляжу, хвостового оперення, шасі, підйомної сили, основних поверхонь управління польотом. Для прийнятного діапазону положення центру ваги використовувався ітераційний метод визначення маси одиниць. У дипломній роботі наведено ескізний проект роликового модуля вантажного трюму та контейнерного відсіку в спеціальній частині
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