Grain Boundary Segregation: the New Sprouts

Some aspects of grain boundary segregation (GBS) are discussed. This paper adds two new sprouts. The first is connected with formation of the atomic complexes in boundary region and their effect on grain boundary diffusion (GBD). The second – with a nonhomogeneity of energy distribution between boundary sites

Surface Tension Gradient as Additional Driving Force for Grain Boundary Diffusion. Equilibrium and Non-Equilibrium Cases

Classic Fisher model of grain-boundary diffusion with leakage into bulk is generalized by consideration of the surface-tension change along the grain boundary.Класична Фішерова модель для зерномежової дифузії з відсмоктуванням в об’єм зерен узагальнено з урахуванням зміни поверхневого натягу вздовж межі зерна.Классическая модель Фишера для зернограничной диффузии с отсосом в объём зёрен обобщена с учётом изменения поверхностного натяжения вдоль границы зерна

Grain Boundary Diffusion with Simultaneous Chemical Interaction in Grain Boundary

The new model is developed, taking into account the simultaneous grain boundary diffusion (within the Fisher—Gibbs approximation) and chemical interaction, which leads to the AB-type molecules’ formation in a binary system. The evaluation of ‘reaction’ effect on the rate of the whole process is made.Розглянуто нову модель, що враховує дифузію вздовж меж зерен (в рамках апроксимації Фішера—Ґіббса) одночасно з хімічною взаємодією, яка веде до утворення молекул типу АВ у бінарних системах. Зроблено оцінку впливу «реакції» на швидкість процесу в цілому.Рассмотрена новая модель, которая учитывает диффузию по границам зёрен (в рамках аппроксимации Фишера—Гиббса) одновременно с химическим взаимодействием, ведущим к образованию молекул типа АВ в бинарных системах. Сделана оценка влияния «реакции» на скорость процесса в целом

Structure and diffusion processes in laminated composites of a Cu-Ti system

Characteristics of diffusion transformations in a multi-layer composite of a Cu-Ti system, which was produced by high-temperature diffusion welding followed by rolling at room temperature, are reportedye

Взаимная диффузия в системах на основе тугоплавких металлов с ОЦК-решеткой: титан–тантал и титан – многокомпонентный (высокоэнтропийный) сплав

In this work, the interdiffusion features in multicomponent (high-entropy) alloys of refractory metals were studied. The following pairs were chosen as the diffusion study objects: titanium–equiatomic alloy (Hf–Nb–Ta–Ti–Zr–Mo) and titanium–tantalum for the sake of comparison. The article covers the issues of sample preparation, microstructure study, sample preparation methodology for diffusion research, and experimental results. Diffusion annealing was carried out for 12 h in a vacuum at a residual argon pressure of 6.65·10–3 Pa and a temperature of 1200 °С. Particular attention was paid to the method of combining diffusion pairs (titanium with tantalum, titanium with alloy) by thermal cycling near the polymorphic transformation temperature in titanium (882 °C) within ± 50 °C. The behaviour of the most characteristic elements (Ta, Zr, Ti) in the weld area after the titanium and alloy diffusion pair joining was demonstrated. This is the first time that data on the dependence of the intensity of the corresponding spectral line for titanium and elements of a multicomponent alloy on the penetration depth were obtained. A change in the signal intensity for system elements was observed at a depth of 150–200 μm, whereas a sharp drop in the signal intensity was seen to occur at depths of about 50 μm. The effective value of the coefficient of diffusion of elements into titanium averaged over all elements of the alloying system (except for titanium) at a temperature of 1200 °C was calculated. The obtained value was compared to reference data: the self-diffusion coefficient in β-titanium and diffusion coefficients in titanium pairs with alloy doping elements.Изучены особенности взаимной диффузии в многокомпонентных (высокоэнтропийных) сплавах на основе тугоплавких металлов. В качестве объектов диффузионного исследования были выбраны следующие пары: титан – эквиатомный сплав (Hf–Nb–Ta–Ti–Zr–Mo) и, для сравнения, титан–тантал. Рассмотрены вопросы приготовления образцов, исследования микроструктуры, методика подготовки образцов для изучения диффузии и экспериментальные результаты. Диффузионный отжиг был проведен в течение 12 ч в вакууме с остаточным давлением аргона 6,65·10–3 Па при температуре 1200 °С. Особое внимание уделено методике соединения диффузионных пар (титана с танталом, титана со сплавом) путем термоциклирования вблизи температуры полиморфного превращения в титане (882 °С) в пределах ±50 °С. Показано поведение наиболее характерных элементов (Ta, Zr, Ti) в области сварного шва после соединения диффузионной пары титана и сплава. Впервые получены данные о зависимости интенсивности соответствующей линии спектра для титана и элементов многокомпонентного сплава от глубины проникновения. Изменение интенсивности сигнала для элементов систем наблюдается на глубине 150–200 мкм, а резкое падение интенсивности сигнала происходит на глубинах порядка 50 мкм. Рассчитано усредненное по всем элементам системы легирования сплава (за исключением титана) эффективное значение коэффициента диффузии элементов в титан при температуре 1200 °С. Проведено сравнение полученного значения со справочными данными: коэффициентом самодиффузии в β-титане, коэффициентами диффузии в парах титана с легирующими элементами сплава

Neurolymphomatosis mimicking neurosarcoidosis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Both neurosarcoidosis and central nervous system lymphoma can be very difficult to diagnose. We describe the case of a patient in whom neurosarcoidosis was strongly suspected, but who was eventually found to have lymphoma. We believe the case to be of interest and practical value to neurologists, oncologists and internists with an interest in inflammatory diseases.</p> <p>Case presentation</p> <p>A diagnosis of neurosarcoidosis was considered in a 49-year-old Caucasian man on the basis of the following symptoms and indications: a cough, bilateral hilar lymphadenopathy confirmed by thoracic computed tomography, the development of an S1 radiculopathy, cerebrospinal fluid abnormalities (raised protein level), bilateral lung hilar and lachrymal gland uptake on a gallium scan, and erythema nodosum confirmed with skin biopsy. These were followed by the development of multiple cranial neuropathies, including seventh nerve palsy. Exhaustive further investigations yielded no evidence for an alternative diagnosis. Treatments with steroids, cyclophosphamide, intravenous immunoglobulin and finally infliximab were of no benefit. He eventually developed cutaneous nodules, a biopsy of which revealed lymphoma that proved resistant to therapy.</p> <p>Conclusion</p> <p>Constant diagnostic vigilance is required in disorders such as neurosarcoidosis.</p

Safety and efficacy of VB-111, an anticancer gene therapy, in patients with recurrent glioblastoma: results of a phase I/II study.

BackgroundVB-111 is a non-replicating adenovirus carrying a Fas-chimera transgene, leading to targeted apoptosis of tumor vascular endothelium and induction of a tumor-specific immune response. This phase I/II study evaluated the safety, tolerability, and efficacy of VB-111 with and without bevacizumab in recurrent glioblastoma (rGBM).MethodsPatients with rGBM (n = 72) received VB-111 in 4 treatment groups: subtherapeutic (VB-111 dose escalation), limited exposure (LE; VB-111 monotherapy until progression), primed combination (VB-111 monotherapy continued upon progression with combination of bevacizumab), and unprimed combination (upfront combination of VB-111 and bevacizumab). The primary endpoint was median overall survival (OS). Secondary endpoints were safety, overall response rate, and progression-free survival (PFS).ResultsVB-111 was well tolerated. The most common adverse event was transient mild-moderate fever. Median OS time was significantly longer in the primed combination group compared with both LE (414 vs 223 days; hazard ratio [HR], 0.48; P = 0.043) and unprimed combination (414 vs 141.5 days; HR, 0.24; P = 0.0056). Patients in the combination phase of the primed combination group had a median PFS time of 90 days compared with 60 in the LE group (HR, 0.36; P = 0.032), and 63 in the unprimed combination group (P = 0.72). Radiographic responders to VB-111 exhibited characteristic, expansive areas of necrosis in the areas of initial enhancing disease.ConclusionsPatients with rGBM who were primed with VB-111 monotherapy that continued after progression with the addition of bevacizumab showed significant survival and PFS advantage, as well as specific imaging characteristics related to VB-111 mechanism of action. These results warrant further assessment in a randomized controlled study