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71.
With the growth of network traffic volume, link congestion cannot be avoided efficiently with conventional routing protocols. By utilizing the single shortest‐path routing algorithm from link state advertisement information, standard routing protocols lack of global awareness and are difficult to be modified in a traditional network environment. Recently, software‐defined network (SDN) provided innovative architecture for researchers to program their own network protocols. With SDN, we can divert heavy traffic to multiple paths in order to resolve link congestion. Furthermore, certain network traffics come in periodic fashion such as peak hours at working days so that we can leverage forecasting for resource management to improve its performance. In this paper, we propose a proactive multipath routing with a predictive mechanism (PMRP) to achieve high‐performance congestion resolution. PMRP has two main concepts: (a) a proactive mechanism where PMRP deploys M/M/1 queue and traffic statistics to simulate weighted delay for possible combinations of multipaths placement of all subnet pairs, and leverage genetic algorithm for accelerating selection of optimized solution, and (b) a predictive mechanism whereby PMRP uses exponential smoothing for demand traffic volumes and variance predictions. Experimental results show a 49% reduction in average delay as compared with single shortest routing, and a 16% reduction in average delay compared with utilization & topology‐aware multipath routing (UTAMP). With the predictive mechanism, PMRP can decrease an additional 20% average delay. Furthermore, PMRP reduces 93% of flow table usage on average as compared with UTAMP.  相似文献   
72.
Energetic carbon ions are promising projectiles used for cancer radiotherapy. A thorough knowledge of how the energy of these ions is deposited in biological media (mainly composed of liquid water) is required. This can be attained by means of detailed computer simulations, both macroscopically (relevant for appropriately delivering the dose) and at the nanoscale (important for determining the inflicted radiobiological damage). The energy lost per unit path length (i.e., the so-called stopping power) of carbon ions is here theoretically calculated within the dielectric formalism from the excitation spectrum of liquid water obtained from two complementary approaches (one relying on an optical-data model and the other exclusively on ab initio calculations). In addition, the energy carried at the nanometre scale by the generated secondary electrons around the ion’s path is simulated by means of a detailed Monte Carlo code. For this purpose, we use the ion and electron cross sections calculated by means of state-of-the art approaches suited to take into account the condensed-phase nature of the liquid water target. As a result of these simulations, the radial dose around the ion’s path is obtained, as well as the distributions of clustered events in nanometric volumes similar to the dimensions of DNA convolutions, contributing to the biological damage for carbon ions in a wide energy range, covering from the plateau to the maximum of the Bragg peak.  相似文献   
73.
Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) represent a group of hematological disorders that are traditionally considered as indistinct slow progressing conditions; still, a subset of cases shows a rapid evolution towards myelofibrotic bone marrow failure. Specific abnormalities in the megakaryocyte lineage seem to play a central role in this evolution, especially in the bone marrow fibrosis but also in the induction of myeloproliferation. In this review, we analyze the current knowledge of prognostic factors of MPNs related to their evolution to myelofibrotic bone marrow failure. Moreover, we focused the role of the megakaryocytic lineage in the various stages of MPNs, with updated examples of MPNs in vitro and in vivo models and new therapeutic implications.  相似文献   
74.
魏玲  臧润清  敕建波  姚秀 《家电科技》2007,230(2):55-57
本文分析了盘管外融冰问题并建立其数学模型;利用该模型模拟了盘管外融冰过程,并对模拟结果进行了分析。分析表明,该模型比较合理,更加接近蓄冷槽内融冰过程的实际情况;循环水量对融冰持续时间有较大影响。所得结论可为今后蓄冷系统的优化计算分析提供理论根据。  相似文献   
75.
Research in science and medicine is witnessing a massive increases in literature concerning extracellular vesicles (EVs). From a morphological point of view, EVs include extracellular vesicles of a micro and nano sizes. However, this simplistic classification does not consider both the source of EVs, including the cells and the species from which Evs are obtained, and the microenvironmental condition during EV production. These two factors are of crucial importance for the potential use of Evs as therapeutic agents. In fact, the choice of the most suitable Evs for drug delivery remains an open debate, inasmuch as the use of Evs of human origin may have at least two major problems: (i) autologous Evs from a patient may deliver dangerous molecules; and (ii) the production of EVs is also limited to cell factory conditions for large-scale industrial use. Recent literature, while limited to only a few papers, when compared to the papers on the use of human EVs, suggests that plant-derived nanovesicles (PDNV) may represent a valuable tool for extensive use in health care.  相似文献   
76.
Varicocele (VC) is the most common abnormality identified in men evaluated for hypofertility. Increased levels of reactive oxygen species (ROS) and reduced antioxidants concentrations are key contributors in varicocele-mediated hypofertility. Moreover, inflammation and alterations in testicular immunity negatively impact male fertility. In particular, NLRP3 inflammasome activation was hypothesized to lead to seminal inflammation, in which the levels of specific cytokines, such as IL-1β and IL-18, are overexpressed. In this review, we described the role played by oxidative stress (OS), inflammation, and NLRP3 inflammasome activation in VC disease. The consequences of ROS overproduction in testis, including inflammation, lipid peroxidation, mitochondrial dysfunction, chromatin damage, and sperm DNA fragmentation, leading to abnormal testicular function and failed spermatogenesis, were highlighted. Finally, we described some therapeutic antioxidant strategies, with recognized beneficial effects in counteracting OS and inflammation in testes, as possible therapeutic drugs against varicocele-mediated hypofertility.  相似文献   
77.
A linear theory based on Maxwell-Vlasov equations and the Laplace transform is presented to describe the large-orbit coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier. A 35-GHz, TE5,1-mode large-orbit coaxial-waveguide CARM amplifier is specifically analyzed. Good agreement between the linear theory and the nonlinear simulations is found in the exponentially growing region of the wave. Results show that the operating magnetic field and the electron-beam energy and average radius substantially affect the power, and especially, a small beam current may be unsuitable to a large-orbit CARM amplifier operation.  相似文献   
78.
Primary aldosteronism (PA) is a pathological condition characterized by an excessive aldosterone secretion; once thought to be rare, PA is now recognized as the most common cause of secondary hypertension. Its prevalence increases with the severity of hypertension, reaching up to 29.1% in patients with resistant hypertension (RH). Both PA and RH are “high-risk phenotypes”, associated with increased cardiovascular morbidity and mortality compared to non-PA and non-RH patients. Aldosterone excess, as occurs in PA, can contribute to the development of a RH phenotype through several mechanisms. First, inappropriate aldosterone levels with respect to the hydro-electrolytic status of the individual can cause salt retention and volume expansion by inducing sodium and water reabsorption in the kidney. Moreover, a growing body of evidence has highlighted the detrimental consequences of “non-classical” effects of aldosterone in several target tissues. Aldosterone-induced vascular remodeling, sympathetic overactivity, insulin resistance, and adipose tissue dysfunction can further contribute to the worsening of arterial hypertension and to the development of drug-resistance. In addition, the pro-oxidative, pro-fibrotic, and pro-inflammatory effects of aldosterone may aggravate end-organ damage, thereby perpetuating a vicious cycle that eventually leads to a more severe hypertensive phenotype. Finally, neither the pathophysiological mechanisms mediating aldosterone-driven blood pressure rise, nor those mediating aldosterone-driven end-organ damage, are specifically blocked by standard first-line anti-hypertensive drugs, which might further account for the drug-resistant phenotype that frequently characterizes PA patients.  相似文献   
79.
The main problem in dealing with energy-harvesting (EH) sensor nodes is represented by the scarcity and non-stationarity of powering, due to the nature of the renewable energy sources. In this work, the authors address the problem of task scheduling in processors located in sensor nodes powered by EH sources. Some interesting solutions have appeared in the literature in the recent past, as the lazy scheduling algorithm (LSA), which represents a performing mix of scheduling effectiveness and ease of implementation. With the aim of achieving a more efficient and conservative management of energy resources, a new improved LSA solution is here proposed. Indeed, the automatic ability of foreseeing at run-time the task energy starving (i.e. the impossibility of finalizing a task due to the lack of power) is integrated within the original LSA approach. Moreover, some modifications have been applied in order to reduce the LSA computational complexity and thus maximizing the amount of energy available for task execution. The resulting technique, namely energy-aware LSA, has then been tested in comparison with the original one, and a relevant performance improvement has been registered both in terms of number of executable tasks and in terms of required computational burden.  相似文献   
80.
Optimization of optical design for developing an LED lens module   总被引:1,自引:0,他引:1  
In this study, a procedure for optimization of an LED lens module design based on 3 LED light sources was divided into two phases. For preliminary optimization of the dimensions of the LED lens module in Stage I, an optical analysis with orthogonal arrays and TracePro (an optical design package) combined with analysis of variance was conducted to investigate relationships between the multiple optical quality characteristics (viewing angle and average illuminance) and dimension parameters and find the initial optimal parameter combination of the LED lens module. In Stage II, the initial optimal parameter combination determined in Stage I was employed to develop an orthogonal array L25(56) for optical simulation. The experimental data of the orthogonal array were used to train and test the back-propagation neural network to develop an optical quality predictor, which was integrated into the genetic algorithms and the particle swarm optimization in order to find the optimal parameter combination that conformed to optical quality. From the experimental results, the proposed optimization procedure contributes to a precise viewing angle to achieve the goal of optical quality and improved the average illuminance in development of the product. The procedure to optimize the optical design developed in this study can be applied to design all types of LED lens modules and improve the optical design and technology of the LED lens industry.  相似文献   
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