MODEL OF GEOMEDIA CONTAINING DEFECTS: COLLECTIVE EFFECTS OF DEFECTS EVOLUTION DURING FORMATION OF POTENTIAL EARTHQUAKE FOCI

This paper describes the statistical thermo-dynamical evolution of an ensemble of defects in the geomedium in the field of externally applied stresses. The authors introduce ‘tensor structural’ variables associated with two specific types of defects, fractures and localized shear faults (Fig. 1). Based on the procedure for averaging of the structural variables by statistical ensembles of defects, a self-consistency equation is developed; it determines the dependence of the macroscopic tensor of defects-induced strain on values of external stresses, the original pattern and interaction of defects. In the dimensionless case, the equation contains only the parameter of structural scaling, i.e. the ratio of specific structural scales, including the size of defects and an average distance between the defects.The self-consistency equation yields three typical responds of the geomedium containing defects to the increasing external stress (Fig. 2). The responses are determined from values of the structural scaling parameter. The concept of non-equilibrium free energy for a medium containing defects, given similar to the Ginzburg-Landau decomposition, allowed to construct evolutionary equations for the introduced parameters of order (deformation due to defects, and the structural scaling parameter) and to explore their solutions (Fig. 3).It is shown that the first response corresponds to stable quasi-plastic deformation of the geomedium, which occurs in regularly located areas characterized by the absence of collective orientation effects. Reducing the structural scaling parameter leads to the second response characterized by the occurrence of an area of meta-stability in the behavior of the medium containing defects, when, at a certain critical stress, the orientation transition takes place in the ensemble of interacting defects, which is accompanied by an abrupt increase of deformation (Fig. 2). Under the given observation/averaging scale, this transition is manifested by localized cataclastic deformation (i.e. a set of weak earthquakes), which migrates in space at a velocity several orders of magnitude lower than the speed of sound, as a ‘slow’ deformation wave (Fig. 3). Further reduction of the structural scaling parameter leads to degeneracy of the orientation meta-stability and formation of localized dissipative defect structures in the medium. Once the critical stress is reached, such structures develop in the blow-up regime, i.e. the mode of avalanche-unstable growth of defects in the localized area that is shrinking eventually. At the scale of observation, this process is manifested as brittle fracturing that causes formation of a deformation zone, which size is proportional to the scale of observation, and corresponds to occurrence of a strong earthquake.On the basis of the proposed model showing the behavior of the geomedium containing defects in the field of external stresses, it is possible to describe main ways of stress relaxation in the rock massives – brittle large-scale destruction and cataclastic deformation as consequences of the collective behavior of defects, which is determined by the structural scaling parameter.Results of this study may prove useful for estimation of critical stresses and assessment of the geomedium status in seismically active regions and be viewed as model representations of the physical hypothesis about the uniform nature of deve­lopment of discontinuities/defects in a wide range of spatial scales

Perforated Peptic Ulcer Combined with Posttraumatic Diaphragmatic Hernia in Third Gestation Trimester: a Clinical Case

Background. Gastric and duodenal ulcers are extremely rare in pregnancy, according to published literature. Peptic ulcer is found in 1 per 4,000 pregnant women, a figure probably underestimated due to its hampered diagnosis in pregnancy. Pregnancy peptic ulcer is considered less expected. Perforated gastric and duodenal ulcers comprise about 1.5 % of total acute abdominal diseases, and the perforation rate in ulcer patients ranges within 5–15 %. This complication afflicts the ages of 20–40 years in men much more frequently than in women. Three perforation types occur: free into abdominal cavity (87 %), contained (9 %), into lesser omentum and retroperitoneal tissue (4 %).Materials and methods. The clinical case describes surgical management of posttraumatic diaphragmatic hernia-comorbid perforated gastric ulcer in a pregnant woman in third trimester. Surgery with postoperative patient management enabled for a favourable outcome.Results and discussion. Perforation-entailing gastric and duodenal ulcers in pregnant women have received negligible attention due to rarity in clinical practice. Paul et al. described 14 cases of duodenal perforation in pregnancy, all fatal.Conclusion. Early diagnosis of surgical pathology during gestation is still difficult contributing to the development of severe complications associated with high mortality. The patient’s admission to a level III interspecialty hospital was key to enable a timely consilium-driven decision of caesarean intervention for saving the child, diagnosing intraoperatively life-threatening complicated surgical diseases and opting for radical surgery that ended in a favourable outcome

МОДЕЛЬ ГЕОСРЕДЫ С ДЕФЕКТАМИ: КОЛЛЕКТИВНЫЕ ЭФФЕКТЫ РАЗВИТИЯ НЕСПЛОШНОСТЕЙ ПРИ ФОРМИРОВАНИИ ПОТЕНЦИАЛЬНЫХ ОЧАГОВ ЗЕМЛЕТРЯСЕНИЙ

This paper describes the statistical thermo-dynamical evolution of an ensemble of defects in the geomedium in the field of externally applied stresses. The authors introduce ‘tensor structural’ variables associated with two specific types of defects, fractures and localized shear faults (Fig. 1). Based on the procedure for averaging of the structural variables by statistical ensembles of defects, a self-consistency equation is developed; it determines the dependence of the macroscopic tensor of defects-induced strain on values of external stresses, the original pattern and interaction of defects. In the dimensionless case, the equation contains only the parameter of structural scaling, i.e. the ratio of specific structural scales, including the size of defects and an average distance between the defects.The self-consistency equation yields three typical responds of the geomedium containing defects to the increasing external stress (Fig. 2). The responses are determined from values of the structural scaling parameter. The concept of non-equilibrium free energy for a medium containing defects, given similar to the Ginzburg-Landau decomposition, allowed to construct evolutionary equations for the introduced parameters of order (deformation due to defects, and the structural scaling parameter) and to explore their solutions (Fig. 3).It is shown that the first response corresponds to stable quasi-plastic deformation of the geomedium, which occurs in regularly located areas characterized by the absence of collective orientation effects. Reducing the structural scaling parameter leads to the second response characterized by the occurrence of an area of meta-stability in the behavior of the medium containing defects, when, at a certain critical stress, the orientation transition takes place in the ensemble of interacting defects, which is accompanied by an abrupt increase of deformation (Fig. 2). Under the given observation/averaging scale, this transition is manifested by localized cataclastic deformation (i.e. a set of weak earthquakes), which migrates in space at a velocity several orders of magnitude lower than the speed of sound, as a ‘slow’ deformation wave (Fig. 3). Further reduction of the structural scaling parameter leads to degeneracy of the orientation meta-stability and formation of localized dissipative defect structures in the medium. Once the critical stress is reached, such structures develop in the blow-up regime, i.e. the mode of avalanche-unstable growth of defects in the localized area that is shrinking eventually. At the scale of observation, this process is manifested as brittle fracturing that causes formation of a deformation zone, which size is proportional to the scale of observation, and corresponds to occurrence of a strong earthquake.On the basis of the proposed model showing the behavior of the geomedium containing defects in the field of external stresses, it is possible to describe main ways of stress relaxation in the rock massives – brittle large-scale destruction and cataclastic deformation as consequences of the collective behavior of defects, which is determined by the structural scaling parameter.Results of this study may prove useful for estimation of critical stresses and assessment of the geomedium status in seismically active regions and be viewed as model representations of the physical hypothesis about the uniform nature of deve­lopment of discontinuities/defects in a wide range of spatial scales. В работе описана статистико-термодинамическая эволюция ансамбля дефектов в геосреде в поле внешнего приложенного напряжения. Авторами вводятся тензорные  структурные переменные, ассоциированные с двумя характерными типами дефектов: трещинами и локализованными сдвигами (рис. 1). Процедура осреднения структурных переменных по статистическому ансамблю дефектов позволила получить уравнение самосогласования, определяющее зависимость макроскопического тензора деформации, индуцированной дефектами, от величины внешних напряжений, исходной структуры и взаимодействия дефектов, которое в безразмерном случае содержит только один параметр – параметр структурного скейлинга. Параметр структурного скейлинга определяется отношением характерных структурных масштабов: размером дефектов и средним расстоянием между дефектами.В результате решения уравнения самосогласования получено три характерных реакции геосреды с дефектами на рост внешнего напряжения (рис. 2), которые определяются величиной параметра структурного скейлинга. Формулировка неравновесной свободной энергии для среды с дефектами в форме, аналогичной разложению Гинзбурга-Ландау, позволила записать эволюционные уравнения для введенных параметров порядка (деформации, обусловленной дефектами, и параметра структурного скейлинга) и исследовать их собственные  решения (рис. 3).Показано, что первая реакция соответствует устойчивому квазипластическому деформированию среды, локализованному в регулярно расположенных пространственных областях, характеризующихся отсутствием коллективных ориентационных эффектов. Уменьшение параметра структурного скейлинга приводит ко второй реакции, которая характеризуется появлением области метастабильности в поведении среды с дефектами, когда при некотором критическом напряжении происходит ориентационный переход в ансамбле взаимодействующих дефектов, сопровождающийся резким скачком деформации (рис. 2). При этом на масштабе наблюдения (осреднения) этот переход проявляется в виде локализованной катакластической деформации (множества слабых землетрясений), мигрирующей по пространству со скоростью, на порядки меньшей скорости звука – «медленной» деформационной волны (рис. 3). Дальнейшее уменьшение параметра структурного скейлинга приводит к вырождению ориентационной метастабильности и формированию в среде локализованных диссипативных дефектных структур, которые при достижении критического напряжения развиваются в режиме с обострением – режиме лавинно-неустойчивого роста дефектов в локализованной пространственной области, уменьшающейся с течением времени. На масштабе наблюдения этот процесс проявляется в виде хрупкого разрушения с формированием зоны разрушения, соизмеримой с самим масштабом наблюдения, и соответствует появлению сильного землетрясения.Таким образом, построенная модель поведения геосреды с дефектами в поле внешних напряжений позволяет описать основные способы релаксации напряжений массивами горных пород: хрупкое крупномасштабное разрушение и катакластическое деформирование, которые являются следствиями коллективного поведения дефектов, определяемого величиной параметра структурного скейлинга.Полученные результаты могут быть полезны для оценки критических напряжений и состояний геосреды в сейсмоактивных районах, а также могут рассматриваться как модельные представления физической гипотезы о единстве природы развития несплошностей (дефектов) на широком спектре пространственных масштабов

ОСОБЕННОСТИ ЛОКАЛИЗАЦИИ ДЕФОРМАЦИИ И РАСПРЕДЕЛЕНИЯ ОЧАГОВ АКУСТИЧЕСКОЙ ЭМИССИИ В ОБРАЗЦАХ ГОРНЫХ ПОРОД ПОД ВОЗДЕЙСТВИЕМ ОДНООСНОГО СЖАТИЯ И ЭЛЕКТРИЧЕСКИХ ИМПУЛЬСОВ

Results of uniaxial compression tests of rock samples in electromagnetic fields are presented. The experiments were performed in the Laboratory of Basic Physics of Strength, Institute of Continuous Media Mechanics, Ural Branch of RAS (ICMM). Deformation of samples was studied, and acoustic emission (AE) signals were recorded. During the tests, loads varied by stages. Specimens of granite from the Kainda deposit in Kyrgyzstan (similar to samples tested at the Research Station of RAS, hereafter RS RAS) were subject to electric pulses at specified levels of compression load. The electric pulses supply was galvanic; two graphite electrodes were fixed at opposite sides of each specimen. The multichannel Amsy-5 Vallen System was used to record AE signals in the six-channel mode, which provided for determination of spatial locations of AE sources. Strain of the specimens was studied with application of original methods of strain computation based on analyses of optical images of deformed specimen surfaces in LaVISION Strain Master System.Acoustic emission experiment data were interpreted on the basis of analyses of the AE activity in time, i.e. the number of AE events per second, and analyses of signals’ energy and AE sources’ locations, i.e. defects.The experiment was conducted at ICMM with the use of the set of equipment with advanced diagnostic capabilities (as compared to earlier experiments described in [Zakupin et al., 2006a, 2006b; Bogomolov et al., 2004]). It can provide new information on properties of acoustic emission and deformation responses of loaded rock specimens to external electric pulses.The research task also included verification of reproducibility of the effect (AE activity) when fracturing rates responded to electrical pulses, which was revealed earlier in studies conducted at RS RAS. In terms of the principle of randomization, such verification is methodologically significant as new effects, i.e. physical laws, can be considered fully indubitable if they prove stable when some parameters of the experiment are changed. Parameters may be arbitrarily modified within a small range, and randomization is thus another common statistical significance criterion for sample sets obtained at the same conditions. At ICMM, the experiments were conducted in compliance with the principle of randomization [Bogomolov et al., 2011]. In this respect, the material of specimens, loading conditions and characteristics of the electrical pulses source were similar to those in the experiments at RS RAS.As evidenced by the experiments, during electromagnetic field stimulation, the AE activity is manyfold higher than the background activity before the impact. This supports the research results reviewed in [Bogomolov et al., 2011] concerning the AE activity increment of 20 % due to electric pulses in the field twice less strong than that in our experiments at ICMM.The AE energy distribution analysis shows that cumulative distributions of the number of AE signals vs energy (i.e. the number of AE signals which energy exceeds a specified threshold value) are power-behaved. This is equivalent to the linear plot of distribution in log units of energy and relative events number, similarly to the case of Gutenberg–Richter law for earthquakes. It is noted that for the logarithmic graphs of distribution by energy, angular coefficients (b-factors) are somewhat different in the period of electric impact and in no-impact periods, which shows that the ratio of AE signals with higher energy indicators is increased in case of external impacts. Such a difference is most evident at the near-critical load when compression amounts to 0.94 fracturing stress value.According to data from the AE source location system, it is revealed that impacts of the electric field are accompanied by redistribution of AE sources through the specimen volume when compression is below 0.9 maximum stress value, which corresponds to the stage of diffusive accumulation of defects. The location system can be effectively applied when events with high amplitudes are accumulated in sufficient number. In this regard, clustering of AE sources (defects) in the area of a future fault was recorded only during the measuring test when the AE activity was quite high at the constant load.As shown by data from the optical diagnostics set of equipment, LаVision Strain Master System, deformation of a specimen takes place in a non-uniform pattern over its surface, which is manifested as consecutively propagating waves of localized strain. This conclusion contributes to the research results obtained earlier for rock samples under tension and compression [Panteleev et al., 2013b, 2013c, 2013d]. Localized axial strain waves and localized radial strain waves (when material particles move in the direction perpendicular to the compression direction) are concurrently observed. Such localized strain waves are ‘slow’ – they propagate at velocities that are by six or seven orders lower than the intrinsic velocity of sound propagation in the material. This observation correlates with the research results obtained earlier in studies of strain localization forms in the course of rock deformation [Zuev, 2011; Zuev et al., 2012].When the loaded specimen is impacted by the electromagnetic field, maximum strain values are slightly decreased in comparison with those in the ordinary case (when only compressive load is applied). This trend seems to be a specific feature of changes in localization of deformation in the loaded rock samples impacted by electric pulses. Besides, the experiments demonstrate that a source of macro-destruction can be induced by the influence of an external electromagnetic field, and the growth of a nucleus of such source can be stabilized during the impact. The above conclusions correlate with the statistical model of a solid body with defects which is developed in ICMM [Panteleev et al., 2011, 2012, 2013a].Представлены результаты испытаний образцов горных пород на одноосное сжатие в присутствии электромагнитного поля. Эксперименты проведены в лаборатории физических основ прочности ИМСС УрО РАН с исследованием деформации образца и регистрацией сигналов акустической эмиссии (АЭ). В процессе испытаний нагрузка изменялась ступенчато. Образцы гранита Каиндинского месторождения, Кыргызстан (однотипные с испытанными на Научной станции РАН), подвергались воздействию электрических импульсов, подаваемых на графитовые электроды, которые закреплялись на противоположных гранях образцов, при фиксированном уровне сжимающего усилия. Запись сигналов акустической эмиссии выполнялась в шестиканальном режиме многоканальной системой Amsy-5 Vallen System, что позволило определить пространственное расположение источников АЭ. Исследование деформации образца производилось при помощи оригинальных методов расчета полей деформации, основанных на корреляционном анализе оптических изображений деформированной поверхности образца (на базе системы LaVision Strain Master).Интерпретация экспериментальных данных акустической эмиссии осуществлялась на основе анализа временной зависимости акустоэмиссионной активности (количество актов АЭ в секунду), а также энергии сигналов и мест расположения их источников (дефектов).Эксперимент в ИМСС УрО РАН на установке с расширенными диагностическими возможностями (по сравнению с ранее проведенными экспериментами, которые описаны в ряде работ [Zakupin et al., 2006a, 2006b; Bogomolov et al., 2004]) способен дать новую информацию о свойствах акустоэмиссионных и деформационных откликов нагруженных породных образцов на внешнее электроимпульсное воздействие.Задача исследований также включала проверку воспроизводимости эффекта отклика скорости трещинообразования (активности АЭ) на воздействие электрических импульсов, который был ранее обнаружен авторами (НС РАН). Такая проверка имеет важное методологическое значение с точки зрения принципа рандомизации – новые эффекты (физические законы) могут считаться полностью достоверными, если они устойчивы к некоторым изменениям параметров постановки эксперимента. В небольших пределах модификация параметров может быть произвольной, отсюда – рандомизация, дополняющая распространенные критерии статистической достоверности для выборок, полученных при одних и тех же условиях. Принципу рандомизации вполне соответствует постановка экспериментов на образцах горных пород в ИМСС УрО РАН [Bogomolov et al., 2011]. В связи с этим, материал образцов, режим нагружения и характеристики источника электрических импульсов выбирались сходными с экспериментами на Научной станции РАН.Эксперименты дали следующие основные результаты. Активность АЭ при стимулировании электромагнитным полем в десятки раз превышает ее фоновый уровень до воздействия. Это существенно дополняет ранее полученные результаты (обобщение в работе [Bogomolov et al., 2011]) прироста активности АЭ порядка 20 % под воздействием электромагнитного поля при вдвое меньшей напряженности электрического поля.При анализе энергетических распределений сигналов АЭ показано, что кумулятивные распределения (т.е. количество сигналов АЭ с энергией, превышающей некоторое пороговое значение от величины этого порога) числа сигналов по энергии соответствуют степенной зависимости. Это эквивалентно линейному графику распределения в логарифмических единицах энергии и числа событий, по аналогии со случаем закона Гутенберга-Рихтера для землетрясений. Обращено внимание на то, что для логарифмических графиков распределений по энергии угловые коэффициенты (b-факторы) в период электровоздействия и во время его отсутствия несколько различаются. Это различие, свидетельствующее об увеличении доли сигналов АЭ с повышенными энергиями при внешнем воздействии, проявилось в наибольшей степени при околокритической нагрузке (напряжение сжатия 0.94 от разрушающего).Применение системы локации источников сигналов АЭ позволило установить, что при сжатии, меньшем 0.90 от максимального (соответствующем стадии диффузного накопления дефектов), воздействие электромагнитного поля сопровождается перераспределением источников по объему образца. Для эффективного использования системы локации необходимо накопление достаточно большого числа событий с большими значениями амплитуд. С учетом этого, результат кластеризации очагов АЭ (дефектов) к области будущего макроразрыва был отмечен лишь в измерительной сессии с достаточно высокой активностью АЭ при постоянной нагрузке.С помощью системы оптической диагностики LаVision Strain Master показано, что процесс деформирования образца происходит неоднородно по всей поверхности в виде последовательно распространяющихся волн локализованной деформации, что дополняет ранее полученные результаты при растяжении и сжатии ряда горных пород [Panteleev et al., 2013b, 2013c, 2013d]. При этом наблюдаются волны локализованной поперечной деформации (волны, в которых частицы материала перемещаются в направлении, перпендикулярном направлению сжатия), и волны локализованной продольной (осевой) деформации. Наблюдаемые волны локализованной деформации являются «медленными», скорость их распространения на шесть-семь порядков меньше характерной скорости звука в материале, что соответствует ранее полученным результатам исследования форм локализации деформации при нарушении горных пород [Zuev, 2011; Zuev et al., 2012].В период дополнительного воздействия электромагнитных полей на нагруженные образцы значения максимумов деформации несколько уменьшаются по сравнению с обычным случаем (только сжимающая нагрузка). Вероятно, эта тенденция – характерная особенность в изменении локализации деформации нагруженных породных образцов под влиянием электрических импульсов. Также была продемонстрирована возможность инициирования очага макроразрушения воздействием внешнего электромагнитного поля и стабилизации роста зародыша такого очага в течение воздействия, что согласуется с ключевыми результатами разрабатываемой в ИМСС УрО РАН статистической модели твердого тела с дефектами [Panteleev et al., 2011, 2012, 2013a]

Management of MDR-TB in HIV co-infected patients in Eastern Europe: Results from the TB:HIV study

Objectives Mortality among HIV patients with tuberculosis (TB) remains high in Eastern Europe (EE), but details of TB and HIV management remain scarce. Methods In this prospective study, we describe the TB treatment regimens of patients with multi-drug resistant (MDR) TB and use of antiretroviral therapy (ART). Results A total of 105 HIV-positive patients had MDR-TB (including 33 with extensive drug resistance) and 130 pan-susceptible TB. Adequate initial TB treatment was provided for 8% of patients with MDR-TB compared with 80% of those with pan-susceptible TB. By twelve months, an estimated 57.3% (95%CI 41.5\u201374.1) of MDR-TB patients had started adequate treatment. While 67% received ART, HIV-RNA suppression was demonstrated in only 23%. Conclusions Our results show that internationally recommended MDR-TB treatment regimens were infrequently used and that ART use and viral suppression was well below the target of 90%, reflecting the challenging patient population and the environment in which health care is provided. Urgent improvement of management of patients with TB/HIV in EE, in particular for those with MDR-TB, is needed and includes widespread access to rapid TB diagnostics, better access to and use of second-line TB drugs, timely ART initiation with viral load monitoring, and integration of TB/HIV care

Incidence of cancer and overall risk of mortality in individuals treated with raltegravir-based and non-raltegravir-based combination antiretroviral therapy regimens

Objectives: There are currently few data on the long-term risk of cancer and death in individuals taking raltegravir (RAL). The aim of this analysis was to evaluate whether there is evidence for an association. Methods: The EuroSIDA cohort was divided into three groups: those starting RAL-based combination antiretroviral therapy (cART) on or after 21 December 2007 (RAL); a historical cohort (HIST) of individuals adding a new antiretroviral (ARV) drug (not RAL) to their cART between 1 January 2005 and 20 December 2007, and a concurrent cohort (CONC) of individuals adding a new ARV drug (not RAL) to their cART on or after 21 December 2007. Baseline characteristics were compared using logistic regression. The incidences of newly diagnosed malignancies and death were compared using Poisson regression. Results: The RAL cohort included 1470 individuals [with 4058 person-years of follow-up (PYFU)] compared with 3787 (4472 PYFU) and 4467 (10 691 PYFU) in the HIST and CONC cohorts, respectively. The prevalence of non-AIDS-related malignancies prior to baseline tended to be higher in the RAL cohort vs. the HIST cohort [adjusted odds ratio (aOR) 1.31; 95% confidence interval (CI) 0.95–1.80] and vs. the CONC cohort (aOR 1.89; 95% CI 1.37–2.61). In intention-to-treat (ITT) analysis (events: RAL, 50; HIST, 45; CONC, 127), the incidence of all new malignancies was 1.11 (95% CI 0.84–1.46) per 100 PYFU in the RAL cohort vs. 1.20 (95% CI 0.90–1.61) and 0.83 (95% CI 0.70–0.99) in the HIST and CONC cohorts, respectively. After adjustment, there was no evidence for a difference in the risk of malignancies [adjusted rate ratio (RR) 0.73; 95% CI 0.47–1.14 for RALvs. HIST; RR 0.95; 95% CI 0.65–1.39 for RALvs. CONC] or mortality (adjusted RR 0.87; 95% CI 0.53–1.43 for RALvs. HIST; RR 1.14; 95% CI 0.76–1.72 for RALvs. CONC). Conclusions: We found no evidence for an oncogenic risk or poorer survival associated with using RAL compared with control groups.Peer reviewe

Establishing a hepatitis C continuum of care among HIV/hepatitis C virus-coinfected individuals in EuroSIDA

Objectives The aim of the study was to establish a methodology for evaluating the hepatitis C continuum of care in HIV/hepatitis C virus (HCV)-coinfected individuals and to characterize the continuum in Europe on 1 January 2015, prior to widespread access to direct-acting antiviral (DAA) therapy. Methods Stages included in the continuum were as follows: anti-HCV antibody positive, HCV RNA tested, currently HCV RNA positive, ever HCV RNA positive, ever received HCV treatment, completed HCV treatment, follow-up HCV RNA test, and cure. Sustained virological response (SVR) could only be assessed for those with a follow-up HCV RNA test and was defined as a negative HCV RNA result measured > 12 or 24 weeks after stopping treatment. Results Numbers and percentages for the stages of the HCV continuum of care were as follows: anti-HCV positive (n = 5173), HCV RNA tested (4207 of 5173; 81.3%), currently HCV RNA positive (3179 of 5173; 61.5%), ever HCV RNA positive (n = 3876), initiated HCV treatment (1693 of 3876; 43.7%), completed HCV treatment (1598 of 3876; 41.2%), follow-up HCV RNA test to allow SVR assessment (1195 of 3876; 30.8%), and cure (629 of 3876; 16.2%). The proportion that achieved SVR was 52.6% (629 of 1195). There were significant differences between regions at each stage of the continuum (P <0.0001). Conclusions In the proposed HCV continuum of care for HIV/HCV-coinfected individuals, we found major gaps at all stages, with almost 20% of anti-HCV-positive individuals having no documented HCV RNA test and a low proportion achieving SVR, in the pre-DAA era.Peer reviewe

Gender differences in the use of cardiovascular interventions in HIV-positive persons; the D:A:D Study

Peer reviewe

The concordance of the limiting antigen and the Bio-Rad avidity assays in persons from Estonia infected mainly with HIV-1 CRF06_cpx

BACKGROUND: Serological assays to determine HIV incidence have contributed to estimates of HIV incidence, monitoring of HIV spread, and evaluation of prevention strategies. Two frequently used incidence assays are the Sedia HIV-1 LAg-Avidity EIA (LAg) and the Bio-Rad avidity incidence (BRAI) assays with a mean duration of recent infection (MDRI) of 130 and 240 days for subtype B infections, respectively. Little is known about how these assays perform with recombinant HIV-1 strains. We evaluated the concordance of these assays in a population infected mainly with HIV-1 CRF06_cpx. MATERIAL/METHODS: Remnant serum samples (n = 288) collected from confirmed, newly-diagnosed HIV-positive persons from Estonia in 2013 were tested. Demographic and clinical data were extracted from clinical databases. LAg was performed according to the manufacturer’s protocol and BRAI testing was done using a validated protocol. Samples with LAg-pending or BRAI-invalid results were reclassified as recent if they were from persons with viral loads <1000 copies/mL or were reclassified as long-term if presenting with AIDS. RESULTS: In total 325 new HIV infections were diagnosed in 2013 in Estonia. Of those 276 persons were tested with both LAg and BRAI. Using assay results only, the recency rate was 44% and 70% by LAg and BRAI, respectively. The majority of samples (92%) recent by LAg were recent by BRAI. Similarly, 89% of samples long-term by BRAI were long-term by LAg. After clinical information was included in the analysis, the recency rate was 44% and 62% for LAg and BRAI, respectively. The majority of samples (86%) recent by LAg were recent by BRAI and 91% of long-term infections by BRAI were long-term by LAg. CONCLUSIONS: Comparison of LAg and BRAI results in this mostly CRF06_cpx-infected population showed good concordance for incidence classification. Our finding of a higher recency rate with BRAI in this population is likely related to the longer MDRI for this assay