Time dependent viscoelastic rheological response of pure, modified and synthetic bituminous binders

Bitumen is a viscoelastic material that exhibits both elastic and viscous components of response and displays both a temperature and time dependent relationship between applied stresses and resultant strains. In addition, as bitumen is responsible for the viscoelastic behaviour of all bituminous materials, it plays a dominant role in defining many of the aspects of asphalt road performance, such as strength and stiffness, permanent deformation and cracking. Although conventional bituminous materials perform satisfactorily in most highway pavement applications, there are situations that require the modification of the binder to enhance the properties of existing asphalt material. The best known form of modification is by means of polymer modification, traditionally used to improve the temperature and time susceptibility of bitumen. Tyre rubber modification is another form using recycled crumb tyre rubber to alter the properties of conventional bitumen. In addition, alternative binders (synthetic polymeric binders as well as renewable, environmental-friendly bio-binders) have entered the bitumen market over the last few years due to concerns over the continued availability of bitumen from current crudes and refinery processes. This paper provides a detailed rheological assessment, under both temperature and time regimes, of a range of conventional, modified and alternative binders in terms of the materials dynamic (oscillatory) viscoelastic response. The rheological results show the improved viscoelastic properties of polymer- and rubber-modified binders in terms of increased complex shear modulus and elastic response, particularly at high temperatures and low frequencies. The synthetic binders were found to demonstrate complex rheological behaviour relative to that seen for conventional bituminous binders

Развитие трех эндокринопатий на фоне терапии ниволумабом

Active implementation of immune checkpoint inhibitors into oncology practice leads to an increase in numbers of observed immune-mediated adverse events, including various endocrinopathies. The focus is on multiple endocrine gland involvement because their predictors are unclear. The paper describes a clinical case of a patient with central cancer of the right lung, who had been administered immune therapy with anti-PD-1 monoclonal antibody (nivolumab). Under this treatment, three endocrine immune-mediated adverse events developed without any concomitant problems from other organs and body systems. The most interesting was the occurrence of adrenal insufficiency and fulminant diabetes mellitus, while, unlike hypothyroidism, which also developed in this patient, those two have been significantly less often described and up to now their incidence, prevalence and association with a certain subgroup of immune checkpoint inhibitors have not been identified. Despite multiple endocrine organ involvement and taking into account positive effects of the anti-tumor treatment, as well as titration of the corresponding hormonal replacement therapy, treatment with nivolumab was continued. Patients treated with immune checkpoint inhibitors require a multidisciplinary team approach including an endocrinologist, because of the potential multiple endocrinopathies, including life-threatening.Активное применение ингибиторов контрольных точек иммунного ответа в онкологической практике приводит к увеличению числа наблюдаемых иммуноопосредованных нежелательных явлений, в том числе различных эндокринопатий. В фокусе внимания случаи с развитием полигландулярных поражений по причине их неясных предикторов. В статье приведено клиническое наблюдение пациента с центральным раком правого легкого, которому была назначена иммунотерапия анти-PD-1-моноклональным антителом (ниволумаб). На фоне данной терапии развилось три эндокринных иммуноопосредованных нежелательных явления без сопутствующего поражения других органов и систем. Наибольший интерес представляет возникновение надпочечниковой недостаточности и фульминантного сахарного диабета, так как в отличие от гипотиреоза, также развившегося у пациента, они описываются значимо реже и на данный момент не определена частота их встречаемости и ассоциация с определенной подгруппой препаратов ингибиторов контрольных точек. Невзирая на множественное поражение органов эндокринной системы, с учетом наличия положительной динамики в противоопухолевом лечении и подбора соответствующей гормональной терапии лечение ниволумабом было продолжено. Пациенты, получающие ингибиторы контрольных точек, нуждаются в мультидисциплинарном ведении с участием эндокринолога, так как существует вероятность развития множественных (в том числе жизнеугрожающих) эндокринопатий

Investigation of statistical characteristics of interaction between the low-frequency oscillations in heart rate variability and peripheral microcirculation in healthy subjects and myocardial infarction patients

Objective. This study compares the statistical characteristics of interaction between 0.1 Hz oscillations in heart rate variability (HRV) and photoplethysmogram (PPG) in healthy subjects and myocardial infarction (Ml) patients. Material and methods. We studied 23 healthy subjects (20 men and 3 women aged 26±3 years) and 23 patients (12 men and 11 women aged 52±4 years) at about one month after Ml. The 10-minute signals of simultaneously recorded cardioin-tervalogram (CIG) and PPG were studied. We calculated the total percentage of phase synchronization between the studied 0.1 Hz oscillations and estimated the distribution functions of duration of synchronous and non-synchronous epochs, the variability of basic frequency of oscillations, and variance of phase noises in 0.1 Hz oscillations in HRV and PPG. Results. The total percentage of phase synchronization between 0.1 Hz oscillations is significantly greater in healthy subjects than in Ml patients (47±3% and 26±4%, respectively). Significant difference between these two groups in the distribution of duration of synchronous and non-synchronous epochs was not revealed. The Ml patients had greater variance between the basic frequencies of 0.1 Hz oscillations in HRV and PPG than healthy subjects. This phenomenon correlates with the increased level of phase noises in the records of Ml patients. Conclusion. The quality of synchronization between 0.1 Hz oscillations in HRV and PPG is associated with the strength of influence of external factors (noises) and variability of the basic frequency of these oscillations