237 research outputs found
A Dynamic-Zone-Based Coordinated Ramp-Metering Algorithm With Queue Constraints for Minnesota's Freeways
Following about 40 years of successful deployment of coordinated traffic-responsive ramp control, a new generation is being developed for Minnesota's freeways based on density measurements, rather than flow rates. This was motivated from recent research indicating that the critical value of density at which capacity is observed is less sensitive and more stable than capacity, thereby allowing the opportunity for more effective control. The main goals of the new approach are to delay the onset of the breakdown and accelerate system recovery when ramp metering is disabled due to the violation of maximum allowable ramp waiting times. This is obtained by a dynamic zone partitioning of the freeway network to identify critical bottleneck locations and coordinated balancing of ramp delays, which aims to avoid mainline breakdown. The effectiveness of the new control strategy is assessed by comparison with the currently deployed version of the stratified zone metering algorithm through microscopic simulation of a real 12-mi 17-ramp freeway section. Simulations show a decrease in delays of mainline and ramp traffic and an improvement of 8% in overall system delays while avoiding maximum ramp delay violations
Functional connectivity analysis of cerebellum using spatially constrained spectral clustering
The human cerebellum contains almost 50% of the neurons in the brain, although its volume does not exceed 10% of the total brain volume. The goal of this study is to derive the functional network of the cerebellum during the resting-state and then compare the ensuing group networks between males and females. Toward this direction, a spatially constrained version of the classic spectral clustering algorithm is proposed and then compared against conventional spectral graph theory approaches, such as spectral clustering, and N-cut, on synthetic data as well as on resting-state fMRI data obtained from the Human Connectome Project (HCP). The extracted atlas was combined with the anatomical atlas of the cerebellum resulting in a functional atlas with 46 regions of interest. As a final step, a gender-based network analysis of the cerebellum was performed using the data-driven atlas along with the concept of the minimum spanning trees. The simulation analysis results confirm the dominance of the spatially constrained spectral clustering approach in discriminating activation patterns under noisy conditions. The network analysis results reveal statistically significant differences in the optimal tree organization between males and females. In addition, the dominance of the left VI lobule in both genders supports the results reported in a previous study of ours. To our knowledge, the extracted atlas comprises the first resting-state atlas of the cerebellum based on HCP data
Regional New Particle Formation over the Eastern Mediterranean and Middle East
Atmospheric new particle formation (NPF) events taking place over large distances between locations, featuring similar characteristics, have been the focus of studies during the last decade. The exact mechanism which triggers NPF still remains indefinable, so are the circumstances under which simultaneous occurrence of such events take place in different environments, let alone in environments which are parted by over 1200 km. In this study, concurrent number size distribution measurements were conducted in the urban environments of Athens (Greece) and Amman (Jordan) as well as the regional background site of Finokalia, Crete, all located within a distance of almost 1300 km for a 6-month period (February–July 2017). During the study period Athens and Finokalia had similar occurrence of NPF (around 20%), while the occurrence in Amman was double. When focusing on the dynamic characteristics at each site, it occurs that formation and growth rates at Amman are similar to those at Finokalia, while lower values in Athens can be ascribed to a higher pre-existing particle number at this urban site. By comparing common NPF events there are 5 concomitant days between all three sites, highly related to air masses origin. Additionally, for another 19 days NPF takes place simultaneously between Finokalia and Amman, which also share common meteorological characteristics, adding to a total of 60% out of 41 NPF events observed at Finokalia, also simultaneously occurring in Amman
Vein Thrombosis Risk in Women and Travel
Deep vein thrombosis (DVT) of the lower limbs is a serious condition that can lead to pulmonary embolism (PE) in about 15–24% of cases. If it is not diagnosed/treated timely, nearly 15% of these PE are lethal. The relationship between travel and staying in the same position for a long time is well-known since World War II. Generally, it is more frequent in air flights. It is also associated with the economic downturn in airplanes because passengers have limited space and have greater difficulty of moving. It is estimated that approximately 1–6% of long-haul passengers arrive at their destination with a clot in their veins, but most DVT are asymptomatic
Radial probe endobronchial ultrasound assisted conventional transbronchial needle aspiration in the diagnosis of solitary peribronchial pulmonary lesion located in the segmental bronchi
Background: The diagnosis of peribronchial pulmonary lesions located in the tertiary bronchi, also known as segmental bronchi, as well as, the 4th order and 5th order segmental bronchi is very difficult. Histopathological specimens cannot be easily obtained by endobronchial biopsies (EBBX) due to the patent but small segmental bronchial lumen. The aim of the present study was to evaluate the diagnostic accuracy and safety of the novel technique with radial probe endobronchial ultrasound (R-EBUS) assisted conventional transbronchial needle aspiration (C-TBNA) in the diagnosis of solitary peribronchial pulmonary lesions located in segmental bronchi from 3th to 5th order. Methods: From December 2014 to December 2015, 16 patients with solitary peribronchial pulmonary lesions in the segmental bronchi from 3th to 5th order confirmed by computed tomography (CT) were enrolled. The lesions were located using radial probe endobronchial ultrasound (R-EBUS) to determine the sites of conventional transbronchial needle aspiration (C-TBNA), then, histopathological specimens were obtained using the technique of C-TBNA. The final pathological diagnosis was made based on the findings from the surgical specimens. Statistical analyses were performed for specimen results and complications. Results: On pathological evaluation, 14 of the 16 specimens were malignant, including 8 adenocarcinomas, 4 squamous cell carcinomas, and 2 small cell carcinomas, while 2 were non-malignant diseases. The diagnostic accuracy rate, sensitivity and missed diagnosis rates were 87.5%, 87.5% and 12.5%, respectively. When Combined the results of cytology with histologic samples obtained from C-TBNA the total diagnostic accuracy rate, sensitivity and missed diagnosis rate were 93.75%, 93.75% and 6.25%, respectively. There were 2 cases of bleeding complications \u3e5 mL after C-TBNA, and both were resolved with endobronchial management. Conclusions: The combination of R-EBUS with C-TBNA was advantageous and safe for the diagnosis of solitary peribronchial pulmonary lesions located in the segmental bronchi. However, possible bleeding complications should be anticipated with needle aspiration. Further verification of this combined application should be investigated in larger clinical trials
Uterine Embolization as a New Treatment Option in Adenomyosis Uteri
Adenomyosis is characterized by the development of endometrial ectopic glands and tissue in the myometrium layer in depth greater than 2.5 mm from the endometrial surface of the separative area by -myomas well as by hypertrophy and hyperplasia of the smooth muscles of the myometrium. This is filtration, not mere displacement, of the myometrium, from the endometrium. Clinical symptoms include dysmenorrhea and menorrhagia. It is diffuse (adenomyosis) or focal (adenomyoma), asymmetrically affects the uterine wall of premenopausal women (usually the posterior) and often coexists with myomas. The pathogenesis of adenomyosis remains unknown. The treatment options are: drug therapy, invasive treatment of fibroids: myomectomy (open—intra-abdominal, laparoscopic, hysteroscopic), hysterectomy, myolysis—cryocatalysis, microwave or radiofrequency thermal catalysis (RF-ablation), ultrasound focus catalysis (FUS), laser photocatalysis and percutaneous selective uterine artery embolization (UAE). Embolization remains an alternative and not a substitute of hysterectomy. The medical indication is made on a case-by-case basis, depending on age, desire for pregnancy and the clinical symptoms of adenomyosis
Premature Birth, Management, Complications
In recent years an increase in premature births (PB) rate has been noticed, as this pregnancy complication that still remain an important cause of perinatal morbidity and mortality, is multifactorial and prediction is not easy in many cases. There are many bibliographic data supporting the view that PB have also genetic predisposition. The trend of “recurrence” of PB in women as well as its increased frequency in ethnic groups suggests its association with genetic factors, either as such or as an interaction of genes and environment. Immunomodulatory molecules and receptors as well as polymorphisms of various genes and/or single nucleotides (single nucleotide polymorphisms, SNPs) now allow with advanced methods of Molecular Biology the identification of genes and proteins involved in the pathophysiology of PB. From the history of a pregnant woman, the main prognostic factor is a previous history of prematurity, while an ultrasound assessment of the cervix between 18 and 24 weeks is suggested, both in the developed and the developing world. According to the latest data, an effective method of successful prevention of premature birth has not been found. The main interventions suggested for the prevention of premature birth are the cervical cerclage, the use of cervical pessary, the use of progesterone orally, subcutaneously or transvaginally, and for treatment administration of tocolytic medication as an attempt to inhibit childbirth for at least 48 hours to make corticosteroids more effective. Despite the positive results in reducing mortality and morbidity of premature infants, the need for more research in the field of prevention, investigation of the genital code and the mechanism of initiation of preterm birth is important
Antiphospholipid Syndrome and Pregnancy-Diagnosis, Complications and Management: An Overview
Antiphospholipid syndrome which is also known as APS is an autoimmune disease which represents an acquired form of thrombophilia. The etiology of APS remains unknown. This disorder occurs when the immune system mistakenly attacks some of the normal human proteins and manifests itself as recurrent arterial or venous thrombosis and it could emerge after abortions or in recurrent pregnancy loss. In APS, the body produces the wrong antibodies against phospholipid-binding proteins, that is present in the blood and plays an important role in coagulation. Antibodies are specific proteins that usually target and neutralize the body’s invaders, such as viruses and bacteria. When antibodies attack phospholipid-binding proteins, blood clots abnormally. Specifically, it could cause blood clots in veins or arteries leading to stroke and various pregnancy complications such as: endometrial death, miscarriage, preeclampsia, intrauterine growth restriction and prematurity. APS is divided into primary and secondary, which is associated with autoimmune diseases and more often with systemic lupus erythematosus (SLE), while antibodies against cardiolipin are detected in many other conditions (infections, malignancies, drugs, etc.). The symptoms of APS, in addition to arterial and/or venous thrombosis and pregnancy complications, are multisystemic and the differential diagnosis of the primary APS from the secondary, in the context of SLE, is of particular clinical interest and is subject of this literature review
The Contribution of Uterine Artery Embolization as a Safe Treatment Option for Uterine Fibroids
Uterine fibroids have remarkably heterogeneous clinical characteristics with unknown exact etiology. The treatment of fibroids should be individualized based on their size, location, growth rate, the symptoms that they cause, the desire to have children and the age of the woman. Embolization is currently the most advanced non-surgical technique. The majority of women report satisfactory post-treatment results like shorter hospitalization period and recovery time in comparison to hysterectomy and improvement or complete remission of clinical symptoms. Complications include amenorrhea (in the majority of cases: recurrence after three months) and infections that are generally treated with antibiotics. The results from most clinical studies and our published experience indicate that embolization improves pelvic symptoms related to uterine fibroids. Collaborative efforts between gynecologists and interventional radiologists are necessary in order to optimize the safety and efficacy of this procedure. In the future, embolization could be generally recommended as treatment option for women who desire future fertility/pregnancy
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