ПЕРВЫЕ РЕЗУЛЬТАТЫ ТАРГЕТНОЙ ТЕРАПИИ ПРИ РАКЕ ПОЧКИ В МОСКВЕ

The paper provides the first interim analysis of a database including information on 427 metastatic kidney cancer patients receiving targeted therapy in the cancer facilities of the Moscow Healthcare Department. It shows a comparative analysis of the periods of first-line targeted therapy with different drugs until progression is established.В статье представлен первый промежуточный анализ базы данных, включающий информацию о 427 больных метастатическим раком почки, получавших таргетную терапию в онкологических учреждениях Департамента здравоохранения г. Москвы. Показан сравнительный анализ сроков проведения первой линии таргетной терапии различными препаратами до установления прогрессирования

A case of successful using a stromal corneal transplant for therapeutic keratoplasty in a patient with herpetic keratitis

Introduction. Herpes virus infection is a cause of inflammatory corneal diseases in 20-57 % of cases. To date, due to the lack and high cost of donor material in Ukraine, approbation of new material for keratoplasty is of great relevance. Purpose. To report a case of successful using a stromal corneal transplant for therapeytic keratoplasty in a patient with herpitic keratitis. Material and Methods. Visual acuity testing, standard ophthalmic examination, microbiology study. Results. Using lyophilized stromal layers made it possible to prevent corneal perforation in a patient with herpetic keratitis. Early operative intervention made it possible to preserve visual function and to avoid severe complications. Conclusions. If urgent keratoplasty is required and keratobioimplant is not available/affordable, lyophilized stromal layers of the cornea with the Descemet's membrane can serve as an alternative material for therapeutic tectonic keratoplasty and can prevent development of severe keratitis complications including descemetocele, corneal perforation etc

Computing the Stationary Distribution of Queueing Systems with Random Resource Requirements via Fast Fourier Transform

Queueing systems with random resource requirements, in which an arriving customer, in addition to a server, demands a random amount of resources from a shared resource pool, have proved useful to analyze wireless communication networks. The stationary distributions of such queuing systems are expressed in terms of truncated convolution powers of the cumulative distribution function of the resource requirements. Discretization of the cumulative distribution function and the application of the fast Fourier transform are a traditional way of calculating convolutions. We suggest finding truncated convolution powers of the cumulative distribution functions by calculating the convolution powers of the truncated cumulative distribution functions via fast Fourier transform. This radically decreases computational complexity. We introduce the concept of resource load and investigate the accuracy of the proposed method at low and high resource loads. It is shown that the proposed method makes it possible to quickly and accurately calculate truncated convolution powers required for the analysis of queuing systems with random resource requirements

On Truncation of the Matrix-Geometric Stationary Distributions

In this paper, we study queueing systems with an infinite and finite number of waiting places that can be modeled by a Quasi-Birth-and-Death process. We derive the conditions under which the stationary distribution for a loss system is a truncation of the stationary distribution of the Quasi-Birth-and-Death process and obtain the stationary distributions of both processes. We apply the obtained results to the analysis of a semi-open network in which a customer from an external queue replaces a customer leaving the system at the node from which the latter departed

On Two Interacting Markovian Queueing Systems

In this paper, we study a Markovian queuing system consisting of two subsystems of an arbitrary structure. Each subsystem generates a multi-class Markovian arrival process of customers arriving to the other subsystem. We derive the necessary and sufficient conditions for the stationary distribution to be of product form and consider some particular cases of the subsystem interaction for which these conditions can be easily verified

Performance Characterization and Traffic Protection in Street Multi-Band Millimeter-Wave and Microwave Deployments

To alleviate the impact of outages caused by dynamic blockage of propagation paths in millimeter wave (mmWave) systems, 3GPP has proposed multi-connectivity operation, where user equipment (UE) maintains simultaneous links to both sub-6 GHz and mmWave BSs. We address one of the most challenging prospective deployments – multi-lane street deployment with intra-and inter-RAT multi-connectivity. By utilizing the mixture of analytical and simulation tools, we first characterize the outage characteristics at mmWave layer. These characteristics further serve as an input to the queuing model characterizing service performance of sub-6 GHz BS serving sub-6 GHz and temporarily offloaded mmWave sessions and implementing traffic protection strategies. Our numerical results show that the use of inter-RAT multi-connectivity to offload mmWave sessions decreases sub-6 GHz session rate multiple times while utilizing multi-connectivity at the mmWave layer allows to partially compensate it. Traffic “jam” road conditions affect the sub-6 GHz session rate reducing it by approximately 20% compared to “normal” road traffic conditions. Furthermore, reserving shares of resources to sub-6 GHz and mmWave traffic favors “heavy-weight” mmWave sessions. On the other hand, individual session resource allocation leads to fair performance. However, this option induces the trade-off between the attained rate and the session drop probability. IEE

Random-access performances measures evaluation with the concept of virtual preamble

Now rapid growth of number of the devices communicating among themselves in LTE (Long-Term Evolution) networks and also increase in volume of transmitted data is observed. The task of reduction of signal and user load, which is serviced by communication networks is relevant. For this purpose algorithms of the simplified interaction between the user devices and a network are being developed and implemented to minimize the spent network resources. In this paper the session initiation procedure between the User Equipment and the LTE eNodeB is analyzed. The problem of the small data transmission formed by the Machine-To-Machine (M2M) connections can be solved by using a Random Access Channel (RACH) for session initiation. Such solution was proposed in the technical report 37.868 of 3GPP (3rd Generation Partnership Project) consortium. For a RACH session initiation procedure it is necessary to evaluate preliminary measures such as access delay, access success probability, access failure pobability, statistics on number of preamble transmissions in case of successful access. In this paper we propose formulas for all listed measures estimation using the virtual preambles approach. Numerical analysis shows the accuracy of the proposed analytical model in the form of the Markov chain. © 2019 Author(s)

Simulation-Based Analysis of Mobility Models for Wireless UAV-to-X Networks

Recently, the use of air base stations located on unmanned aerial vehicles (UAVs) has attracted great attention. Static deployment of a sufficient number of UAVs allows uniform wireless coverage in the demanded areas, where the existing cellular infrastructure has white spots or insufficient capacity. However, UAVs mobility may be required for applications, where UAVs are used to provide communications for mobile groups of users (e.g., massive sport or community events like marathon or music festival) or for patrolling tasks with relaxed requirements for data transmission delays (for example, when collecting information from a large number of mMTC sensors). In such tasks, the movement of UAVs can significantly increase the efficiency of the system, since in this case the coverage of the area can be provided by a smaller number of UAVs following the dynamics of ground users. Nowadays, more and more often the question arises about the mobile communications availability in a remote area, for example, during public events or search operations. The lack of on-demand connectivity with sufficient quality in such areas is unacceptable in modern conditions. Therefore, the study of the behavior of a dynamic UAV network is necessary for decision-making operation in such scenarios. The main contribution of this work is making the user mobility model more human-alike according to the real scenarios. The paper considers two models of UAVs movement, the effectiveness of which is estimated from the point of view of the coverage probability and average fade duration of the signal. © 2020, Springer Nature Switzerland AG

Quantifying the Density of mmWave NR Deployments for Provisioning Multi-Layer VR Services

The 5G New Radio (NR) technology operating in millimeter wave (mmWave) frequency band is designed for support bandwidth-greedy applications requiring extraordinary rates at the access interface. However, the use of directional antenna radiation patterns, as well as extremely large path losses and blockage phenomenon, requires efficient algorithms to support these services. In this study, we consider the multi-layer virtual reality (VR) service that utilizes multicast capabilities for baseline layer and unicast transmissions for delivering an enhanced experience. By utilizing the tools of stochastic geometry and queuing theory we develop a simple algorithm allowing to estimate the deployment density of mmWave NR base stations (BS) supporting prescribed delivery guarantees. Our numerical results show that the highest gains of utilizing multicast service for distributing base layer is observed for high UE densities. Despite of its simplicity, the proposed multicast group formation scheme operates close to the state-of-the-art algorithms utilizing the widest beams with longest coverage distance in approximately 50-70% of cases when UE density is lambda >= 0.3. Among other parameters, QoS profile and UE density have a profound impact on the required density of NR BSs while the effect of blockers density is non-linear having the greatest impact on strict QoS profiles. Depending on the system and service parameters the required density of NR BSs may vary in the range of 20-250 BS/km(2)