Wave packet dynamics in a monolayer graphene

The dynamics of charge particles described by Gaussian wave packet in monolayer graphene is studied analytically and numerically. We demonstrate that the shape of wave packet at arbitrary time depends on correlation between the initial electron amplitudes $\psi_1(\vec r,0)$ and $\psi_2(\vec r,0)$ on the sublattices $A$ and $B$ correspondingly (i.e. pseudospin polarization). For the transverse pseudospin polarization the motion of the center of wave packet occurs in the direction perpendicular to the average momentum ${\vec p_0}=\hbar \vec{k_0}$. Moreover, in this case the initial wave packet splits into two parts moving with opposite velocities along ${\vec p_0}$. If the initial direction of pseudospin coincides with average momentum the splitting is absent and the center of wave packet is displaced at $t>0$ along the same direction. The results of our calculations show that all types of motion experience {\it zitterbewegung}. Besides, depending on initial polarization the velocity of the packet center may have the constant component $v_c=uf(a)$, where $u\approx 10^8 cm/s$ is the Fermi velocity and $f(a)$ is a function of the parameter $a=k_0d$ ($d$ is the initial width of wave packet). As a result, the direction of the packet motion is determined not only by the orientation of the average momentum, but mainly by the phase difference between the up- and low- components of the wave functions. Similar peculiarities of the dynamics of 2D electron wave packet connected with initial spin polarization should take place in the semiconductor quantum well under the influence of the Rashba spin-orbit coupling.Comment: 7 pages, 8 figures, to be published in Phys. Rev.

Wave packet dynamics in hole Luttinger systems

For hole systems with an effective spin 3/2 we analyzed analytically and numerically the evolution of wave packets with the different initial polarizations. The dynamics of such systems is determined by the $4\times 4$ Luttinger Hamiltonian. We work in the space of arbitrary superposition of light- and heavy-hole states of the "one-particle system". For 2D packets we obtained the analytical solution for the components of wave function and analyzed the space-time dependence of probability densities as well as angular momentum densities. Depending on the value of the parameter $a=k_0d$ ($k_0$ is the average momentum vector and $d$ is the packet width) two scenarios of evolution are realized. For $a>>1$ the initial wave packet splits into two parts and the coordinates of packet center experience the transient oscillations or {\it Zitterbewegung} (ZB) as for other two-band systems. In the case when $a0$ remains almost cylindrically symmetric and the ripples arise at the circumference of wave packet. The ZB in this case is absent. We evaluated and visualized for different values of parameter $a$ the space-time dependence of angular momentum densities, which have the multipole structure. It was shown that the average momentum components can precess in the absence of external or effective magnetic fields due to the interference of the light- and heavy hole states. For localized initial states this precession has a transient character.Comment: 9 pages, 8 gigur

Space-time evolution of Dirac wave packets

In this work we study the dynamics of free 3D relativistic Gaussian wave packets with different spin polarization. We analyze the connection between the symmetry of initial state and the dynamical characteristics of moving particle. The corresponding solutions of Dirac equation having different types of symmetry were evaluated analytically and numerically and after that the electron probability densities, as well as, the spin densities were visualized. The average values of velocity of the packet center and the average spin were calculated analytically, and the parameters of transient Zitterbewegung in different directions were obtained. These results can be useful for the interpretation of future experiments with trapped ions.Comment: 10 pages, 7 figure

ЭПИДЕМИОЛОГИЧЕСКИЙ МОНИТОРИНГ И ПРОФИЛАКТИКА ГЕМОФИЛЬНОЙ ИНФЕКЦИИ ТИПА B В РОССИЙСКОЙ ФЕДЕРАЦИИ

At three study sites, incidence rates of meningitis caused by Haemophilus influenzae type b exceeded the threshold of 10 cases per на 100,000 children under 5 and mandated vaccination. Both vaccines the use of which is permitted in the Russian Federation are efficacious and safe. In order to make immunization a success, it’s imperative to take the comprehensive approach comprising not only vaccine procurement but also cold chain reinforcement, laboratory capacity building including staff training, computerization of primary care facilities as well as other feasible types of healthcare modernization. Immunization against Haemophilus influenzae type b not only prevents in children purulent bacterial meningitis of aforementioned etiology but also reduces rates of respiratory infections.В трех центрах исследования показатели заболеваемости менингитом, вызванным Haemophilus influenzae типа b, превышали 10 случаев на 100 000 детского населения в возрасте до 5 лет и обосновывали проведение массовой вакцинации. Обе вакцины, разрешенные к применению в Российской федерации, эффективны и безопасны. Чтобы при проведении вакцинации добиться успеха, необходимо не только поставить вакцины, но и подойти к решению вопроса комплексно, включая укрепление холодовой цепи и лабораторного потенциала с проведением дополнительной подготовки персонала, компьютеризацию учреждений первичной медико-санитарной помощи и иные осуществимые виды модернизации здравоохранения. Иммунизация против гемофильной инфекции типа b предотвращает возникновение у детей гнойных бактериальных менингитов соответствующей этиологии и уменьшает заболеваемость респираторными инфекциями

DIAGNOSTIC MARKERS OF ALLERGIC BRONCHOPULMONARY ASPERGILLOSIS IN PATIENTS WITH BRONCHIAL ASTHMA

Studies of probable significance of different immunological mediators for the development of chronic allergic inflammation in patients with allergic bronchopulmonary aspergillosis (ABPA) are necessary in order to specify potential targets for therapeutic intervention and timely diagnosis of the disease. The purpose of present study was to determine the features of immune response regulation, and to identify diagnostic markers associated with development of ABPA in patients with bronchial asthma, and to evaluate clinical and immunological efficacy of specific antimycotic therapy.The study involved 13 patients with ABPA, 14 patients with bronchial asthma with fungal sensitization (BAFS), 17 patients with bronchial asthma (BA) and 12 apparently healthy individuals. Levels of thymic stromal lymphopoietin (TSLP), thymus and activation-regulated chemokine (TARC), IL-8, as well as levels of total IgE and specific IgE to Aspergillus fumigatus (A. fumigatus) were measured in blood serum by enzyme immunoassay; blood eosinophil counts were also made. Monitoring of these immunological markers in the course of antimycotic therapy was carried out.Significantly higher numbers of eosinophils, increased levels of total IgE and sIgE for A. fumigatus, as well as TARC and IL-8 in serum were revealed in patients with ABPA when compared to the patients with BA. No significant differences in TSLP content were found between the examined groups of patients. A positive correlation between the levels of sIgE to A. fumigatus and contents of TARC and IL-8, numbers of eosinophils, and total IgE levels confirms the important diagnostic value of proinflammatory cytokines in ABPA patients. In the course of itraconazole medication, a positive clinical and immunological dynamics in ABPA patients was revealed. After 12 weeks of therapy, a significant increase in AST, FEV1 and Tiffno respiratory indexes, along with decreased number of eosinophils, total IgE levels, and a trend towards a decrease in TARC and IL-8 levels were documented. This dynamics confirms clinical efficiency of antifungal drugs when treating chronic allergic inflammation in ABPA patients.Implementation of modern immunological biomarkers, alongside with traditional indicators, will allow to differentially evaluate a probability for ABLA development in patients with bronchial asthma, to present additional evidence for discerning early stages of the disease, and to conclude about the efficiency of the therapy applied

Клиническая эффективность пневмококковой конъюгированной 13-валентной вакцины у детей раннего возраста

Objective: Our aim was to study the clinical efficacy of pneumococcal conjugate 13-valent vaccine (PCV13) in children aged less than 3 years.Methods: retrospective comparative study of the incidence of acute respiratory infections (ARI), otitis and pneumonia during the first three years of life in 184 children vaccinated with PKV13 and 186 unvaccinated peers.Results: 91 of 184 children (49.4%) were vaccinated during the 1st year of life, 61 (33.2%) — during the 2nd year, and 32 (17.4%) — during the 3rd year. Number of ARI per 1 child among children vaccinated in the 1st year of life was 5.5 times less than among unvaccinated children (0.42 and 2.31 cases); frequency of otitis during the second year of life was 6.8 times less (7.6% and 52.1%, р < 0,01), and during the third — 34.7 times less (1.1% and 38.2%, р < 0,01). All children vaccinated before the age of 1 were 6.3 times less (1.1% and 6.9%) ill with pneumonias. Additionally it was noted that number of ARI per 1 person among children, vaccinated during the 1st year of life, during the third year of life was lower than among children vaccinated later (0.42; 1.02; 2.03 respectively). There also was a significant in otitis number between children vaccinated during the first and the third years of life (1.1 and 15.6% р < 0,01).Conclusion: to reduce the incidence of ARI, otitis and pneumonia in children, it is necessary to vaccinate children with PCV13 in the age under 1 year. «Catching up» immunization of the second and third years of life is effective, but to a lesser extent.Цель исследования: изучить клиническую эффективность вакцинации против пневмококковой инфекции конъюгированной тринадцативалентной вакциной (ПКВ13) детей в возрасте до 3 лет.Методы: ретроспективное сравнительное исследование заболеваемости острыми респираторными инфекциями (ОРИ), отитами и пневмониями на протяжении первых трех лет жизни у 184 детей, привитых ПКВ13, и их 186 непривитых сверстников.Результаты. На 1-м году жизни вакцинирован 91 ребенок из 184 (49,4%), на 2-м — 61 (33,2%), на 3-м — 32 (17,4%). У привитых на первом году жизни по сравнению с непривитыми число ОРИ на 1 ребенка на третьем году жизни было в 5,5 раз меньше (0,42 и 2,31 случая), частота отитов на втором году жизни — в 6,8 раз меньше (7,6 и 52,1%; р < 0,01), на третьем — в 34,7 раз меньше (1,1 и 38,2%; р < 0,01). Пневмониями за все три года привитые до одного года болели в 6,3 раза меньше (1,1 и 6,9%). Дополнительно было отмечено, что у детей, вакцинированных на первом году жизни, на третьем году число ОРИ на 1 человека было меньше, чем у привитых позже (0,42; 1,02; 2,03 соответственно на первом, втором и третьем году наблюдения), также достоверно различалось число отитов между привитыми на первом и третьем годах (1,1 и 15,6%; р < 0,01).Заключение. Для снижения заболеваемости детей ОРИ, отитами и пневмониями необходима вакцинация ПКВ13 в возрасте до одного года. «Нагоняющая» иммунизация на втором и третьем годах жизни эффективна, но в меньшей степени

BASOPHILE ACTIVATION TEST FOR THE DIAGNOSTICS OF FUNGAL SENSITIZATION IN THE PATIENTS WITH CYSTIC FIBROSIS

Aspergillus fumigatus colonization in the patients with cystic fibrosis (CF) may cause sensitization against A. fumigatus and/or allergic bronchopulmonary aspergillosis (ABPA), which significantly worsens the course of underlying disease. At the present time, new diagnostic tests are searched for detection of fungal sensitization in these patients. The aim of this work was to evaluate an opportunity of application of basophile activation test with A. fumigatus allergen in vitro using flow cytometry, aiming for identification of fungal sensitization in the CF patients. The study included 190 patients with CF aged 1 to 37 years. All the patients underwent common allergy screening (skin tests with fungal allergens, determination of serum levels of total IgE and specific IgE for the fungal allergens), and mycological examination (microscopy and culture of respiratory substrates). Computed tomography of the chest was performed upon clinical indications. The basophil activation test with the A. fumigatus allergen was performed in 10 CF patients with ABPA, and 10 CF patients without ABPA, in addition to the standard allergological examination. Frequency of sensitization to A. fumigatus in the patients with cystic fibrosis was 27%, the incidence of allergic bronchopulmonary aspergillosis was 5.7%. The number of eosinophils, total IgE and specific IgE levels in CF patients with ABPA were significantly higher than in CF patients without ABPA. In blood of the ABPA patients we have identified 68.5 (52.5-81.5%) of basophilic leukocytes activated by A. fumigatus allergen, with a stimulation index of 17.07 (10.30-27.70). In appropriate comparison group, the stimulation index did not exceed 1.5 (p = 0.000). Direct positive correlation between the levels of specific IgE to A. fumigatus and the number of basophils activated by A. fumigatus allergens was revealed (r = 0.77; р < 0.05). FVC values and the body mass index in CF patients with ABPA were significantly lower when compared with the patients without fungal sensitization. Introduction of the basophil activation test, along with standard techniques, may enable a more differentiated assessment of ABPA development in CF patients. Timely detection of associations between A. fumigatus sensitization and clinical status of CF patients will facilitate early and effective administration of specific therapy

СЕРОТИПЫ STREPTOCOCCUS PNEUMONIAE, ВЫЗЫВАЮЩИХ ВЕДУЩИЕ НОЗОЛОГИЧЕСКИЕ ФОРМЫ ПНЕВМОКОККОВЫХ ИНФЕКЦИЙ

First in Russia prospective non-interventional hospital-based study on Streptococcus pneumoniae serotypes causing meningitis and acute otitis media (AOM) in children and community-acquired pneumonia (CAP) in children and adults, as well as serotype coverage by pneumococcal conjugate vaccines (PCV’s) of different composition has been conducted. Serotypes 19F, 14 and serogroup 6 are the leading in meningitis; serotype coverage is 70,6% for PCV7, and 76,5% – for PCV10 and PCV13. Among S. pneumoniae serotypes causing AOM 19F, 3, 23F and serogroup 6 have been the most prevalent in Saint Petersburg. PCV7 and PCV10 provide equal serotypes coverage in AOM – 63,2% among children 0–2 years old, and 32,5% among children 5–17 years old. PCV13 covers up to 79% of serotypes in infants. In CAP PCV7 and PCV10 provide 57,1% serotype coverage in children and 56,1% – in adults. Serotype coverage in CAP for PCV13 has been 14,3% and 34,5% higher for children and adults, correspondingly. Obtained data supports PCV inclusion in children immunization program in Saint Petersburg, whereas PCV13 provides the broadest serotype coverage. In the course PCV’s implementation continued pneumococcal infection surveillance is advisable.Впервые в России в проспективном неинтервенционном госпитальном эпидемиологическом исследовании изучен серотиповой состав Streptococcus pneumoniae, вызывающих менингиты, внебольничную пневмонию и острый средний отит (ОСО), а также охват циркулирующих серотипов пневмококковыми конъюгированными вакцинами (ПКВ) различного состава. К ведущим серотипам S. pneumoniae, вызывающим у детей гнойный менингит, относятся 19F, 14 и серогруппа 6. Охват серотипов S. pneumoniae, вызывающих гнойный менингит для ПКВ7, составляет 70,6%, а для ПКВ10 и ПКВ13 – 76,5%. Ведущими серотипами пневмококков, вызывающих ОСО, в Санкт-Петербурге являются серотипы 19F, 3, 23F и серогруппа 6. Охват серотипов для ПКВ7 и ПКВ10 одинаков и составляет 63,2% для детей в возрасте 0–2 лет и 32,5% для детей в возрасте 5–17 лет. Для ПКВ13 эти показатели составляют соответственно 79% и 55%. При внебольничной пневмонии ПКВ7 и ПКВ10 обеспечивали одинаковый охват: 57,1% у детей и 56,1% у взрослых. Для ПКВ13 эти показатели были на 14,3% больше у детей и на 34,5% у взрослых. Полученные данные обосновывают целесообразность применения пневмококковых конъюгированных вакцин для массовой иммунизации детей в Санкт-Петербурге, при этом ПКВ13 обеспечивает наибольший охват серотипов S. pneumoniae, вызывающих основные пневмококковые заболевания. Для оценки эффективности вакцинации целесообразно продолжить эпидемиологическое наблюдение за пневмококковыми инфекциями после проведения массовой иммунизации ПКВ13