Interaction of Nitrogen-Vacancy Centers in Diamond with a Dense Ensemble of Carbon-13

The nitrogen-vacancy center in diamond attracts a lot of attention in sensing applications, mainly for temperature, magnetic field, and rotation measurements. Nuclear spins of carbon-13 surrounding the nitrogen-vacancy center can be used as a memory or sensing element. In the current work, a diamond plate with a relatively large concentration of carbon-13 was synthesized and examined. The spectrum of optically detected magnetic resonance was recorded and analyzed in a magnetic field range of 5-200 G. A strain-independent measurement technique of carbon-13 isotope concentration based on the analysis of magnetic resonance spectra was developed. Additionally, narrow features in the spectrum were detected and understood

Tuberculosis in HIV-infected children in Europe, Thailand and Brazil: paediatric TB-HIV EuroCoord study

SETTING: Centres participating in the Paediatric European Network for Treatment of AIDS (PENTA), including Thailand and Brazil. OBJECTIVE: To describe the incidence, presentation, treatment and treatment outcomes of tuberculosis (TB) in human immunodeficiency virus (HIV) infected children. DESIGN: Observational study of TB diagnosed in HIV-infected children in 2011–2013. RESULTS: Of 4265 children aged <16 years, 127 (3%) were diagnosed with TB: 6 (5%) in Western Europe, 80 (63%) in Eastern Europe, 27 (21%) in Thailand and 14 (11%) in Brazil, with estimated TB incidence rates of respectively 239, 982, 1633 and 2551 per 100 000 person-years (py). The majority (94%) had acquired HIV perinatally. The median age at TB diagnosis was 6.8 years (interquartile range 3.0–11.5). Over half (52%) had advanced/severe World Health Organization stage immunodeficiency; 67 (53%) were not on antiretroviral therapy (ART) at TB diagnosis. Preventive anti-tuberculosis treatment was given to 23% (n = 23) of 102 children diagnosed with HIV before TB. Eleven children had unfavourable TB outcomes: 4 died, 5 did not complete treatment, 1 had recurrent TB and 1 had an unknown outcome. In univariable analysis, previous diagnosis of acquired immune-deficiency syndrome, not being virologically suppressed on ART at TB diagnosis and region (Brazil) were significantly associated with unfavourable TB outcomes. CONCLUSION: Most TB cases were from countries with high TB prevalence. The majority (91%) had favourable outcomes. Universal ART and TB prophylaxis may reduce missed opportunities for TB prevention

How Chaotic is the Stadium Billiard? A Semiclassical Analysis

The impression gained from the literature published to date is that the spectrum of the stadium billiard can be adequately described, semiclassically, by the Gutzwiller periodic orbit trace formula together with a modified treatment of the marginally stable family of bouncing ball orbits. I show that this belief is erroneous. The Gutzwiller trace formula is not applicable for the phase space dynamics near the bouncing ball orbits. Unstable periodic orbits close to the marginally stable family in phase space cannot be treated as isolated stationary phase points when approximating the trace of the Green function. Semiclassical contributions to the trace show an $\hbar$ - dependent transition from hard chaos to integrable behavior for trajectories approaching the bouncing ball orbits. A whole region in phase space surrounding the marginal stable family acts, semiclassically, like a stable island with boundaries being explicitly $\hbar$-dependent. The localized bouncing ball states found in the billiard derive from this semiclassically stable island. The bouncing ball orbits themselves, however, do not contribute to individual eigenvalues in the spectrum. An EBK-like quantization of the regular bouncing ball eigenstates in the stadium can be derived. The stadium billiard is thus an ideal model for studying the influence of almost regular dynamics near marginally stable boundaries on quantum mechanics.Comment: 27 pages, 6 figures, submitted to J. Phys.

Абсцесс легкого как осложнение COVID-19-пневмонии: клинический случай

The article describes a case of polysegmental destructive viral-bacterial pneumonia complicated with acute pulmonary abscess, pleural empyema, and pneumopleurofibrosis in a 50-year-old female patient infected with the SARS-CoV-2 virus. The first clinical, laboratory and radiological signs of purulent-necrotic inflammation appeared only 20 days after receiving a positive RT-PCR test result with a nasopharyngeal swab. A month later, an emerging abscess in the lower lobe of the right lung was diagnosed. Subsequently, it spontaneously drained into the pleural cavity.Coagulopathy with the formation of microthrombi in small pulmonary vessels is one of the causative factors of lung abscess in patients infected with the SARS-CoV-2 virus.В статье описан случай полисегментарной деструктивной вирусно-бактериальной пневмонии, осложненной острым абсцессом легкого, эмпиемой плевры и пневмоплеврофиброзом у 50-летней пациентки, находившейся на лечении в стационаре по поводу COVID-19-пневмонии, подтвержденной выявлением ПЦР РНК SARS-CoV-2. Первые клинико-лабораторно-рентгенологические признаки гнойно-некротического воспаления появились через 20 дней после получения положительного результата ПЦР-теста в мазке со слизистой носоглотки. Еще через месяц был диагностирован формирующийся абсцесс в нижней доле правого легкого, который в последующем самопроизвольно дренировался в плевральную полость.Одним из факторов формирования абсцесса легкого при COVID-19-пневмонии может быть нарушение свертывающей системы крови с образованием микротромбов в мелких легочных сосудах

The complex light-curve of the afterglow of GRB071010A

We present and discuss the results of an extensive observational campaign devoted to GRB071010A, a long-duration gamma-ray burst detected by the Swift satellite. This event was followed for almost a month in the optical/near-infrared (NIR) with various telescopes starting from about 2min after the high-energy event. Swift-XRT observations started only later at about 0.4d. The light-curve evolution allows us to single out an initial rising phase with a maximum at about 7min, possibly the afterglow onset in the context of the standard fireball model, which is then followed by a smooth decay interrupted by a sharp rebrightening at about 0.6d. The rebrightening was visible in both the optical/NIR and X-rays and can be interpreted as an episode of discrete energy injection, although various alternatives are possible. A steepening of the afterglow light curve is recorded at about 1d. The entire evolution of the optical/NIR afterglow is consistent with being achromatic. This could be one of the few identified GRB afterglows with an achromatic break in the X-ray through the optical/NIR bands. Polarimetry was also obtained at about 1d, just after the rebrightening and almost coincident with the steepening. This provided a fairly tight upper limit of 0.9% for the polarized-flux fraction.Comment: 11 pages, 3 figures, MNRAS, in pres

The complex light-curve of the afterglow of GRB071010A

We present and discuss the results of an extensive observational campaign devoted to GRB071010A, a long-duration gamma-ray burst detected by the Swift satellite. This event was followed for almost a month in the optical/near-infrared (NIR) with various telescopes starting from about 2min after the high-energy event. Swift-XRT observations started only later at about 0.4d. The light-curve evolution allows us to single out an initial rising phase with a maximum at about 7min, possibly the afterglow onset in the context of the standard fireball model, which is then followed by a smooth decay interrupted by a sharp rebrightening at about 0.6d. The rebrightening was visible in both the optical/NIR and X-rays and can be interpreted as an episode of discrete energy injection, although various alternatives are possible. A steepening of the afterglow light curve is recorded at about 1d. The entire evolution of the optical/NIR afterglow is consistent with being achromatic. This could be one of the few identified GRB afterglows with an achromatic break in the X-ray through the optical/NIR bands. Polarimetry was also obtained at about 1d, just after the rebrightening and almost coincident with the steepening. This provided a fairly tight upper limit of 0.9% for the polarized-flux fraction.Comment: 11 pages, 3 figures, MNRAS, in pres

Разработка подходов для исследования биораспределения бицистронной терапевтической плазмидной конструкции в организме мыши

Relevance. The use of gene therapy drugs for the treatment of genetic diseases and stimulation of regeneration processes is lengthy and involves repeated injections, which may lead to increased dissemination of gene therapy constructs from the injection site and undesirable ectopic expression of growth factors encoded in them. Existing approaches to study the pharmacokinetics of a drug to assess the dissemination of a gene therapy drug from the site of administration are not applicable. Objective: to evaluate the suitability of the real-time PCR method for studying the biodistribution of a promising gene therapy drug in mice during a course of use. Methods. Male F1 CBA×C57/Black mice after nerve injury were injected with the test plasmid into the denervated tibial muscle after nerve injury, as well as after 4, 9 and 13 days at a dosage of 60 and 120 μg/mouse. After 7, 14, and 28 days, organ and tissue samples were removed, total DNA was isolated, and plasmid DNA content was assessed by real-time PCR. Results. We have shown that the studied genetic construct is able to disseminate from the injection site. We have found that the peak of dissemination for this construct in the organs and tissues of the mouse is reached 14–28 days after the end of the course application, while ectopic expression of growth factors is not observed in them. Conclusion. The proposed method is specific, highly sensitive, and linear over a wide range of concentrations. Thus, it can be recommended for studying the biodistribution of potential gene therapy drugs in the body of experimental animals as part of a preclinical studies complex.Актуальность. Применение генотерапевтических препаратов для лечения генетических заболеваний и стимуляции процессов регенерации является длительным и подразумевает осуществление повторных инъекций, что может привести к усилению диссеминации генотерапевтических конструкций из области введения и нежелательной эктопической экспрессии закодированных в них ростовых факторов. Существующие подходы по изучению фармакокинетики лекарственного препарата для оценки диссеминации генотерапевтического препарата из очага введения неприменимы. Цель: оценить пригодность метода ПЦР в реальном времени для изучения биораспределения перспективного генотерапевтического препарата в организме мыши при курсовом применении. Методы. Самцам мышей F1 CBA×C57/Black делали инъекции исследуемой плазмиды в денервированную большеберцовую мышцу после травмы нерва, а также через 4, 9 и 13 дней в дозировке 60 и 120 мкг/мышь. Через 7, 14 и 28 дней после окончания курса инъекций образцы органов и тканей изымали, тотальную ДНК выделяли, и содержание плазмидной ДНК оценивали с помощью ПЦР в реальном времени. Результаты. Было показано, что изученная генетическая конструкция способна диссеминировать из области введения. Было установлено, что пик диссеминации для данной конструкции в органах и тканях мыши достигается через 14–28 суток после окончания курсового применения, при этом эктопической экспрессии факторов роста в них не наблюдается. Заключение. Предложенный метод является специфичным, высокочувствительным и линеен в широком диапазоне концентраций. Таким образом, он может быть рекомендован для изучения биораспределения потенциальных генотерапевтических препаратов в организме экспериментальных животных в рамках комплекса доклинических исследований