Measles humoral immunity in health-care workers

Healthcare-workers are at risk of contact with measles patients and disease transmission. Measles-infected employees of healthcare facilities may contribute to the nosocomial measles spread and serve as a source of infection for most susceptible cohorts such as pregnant women, neonates, and immunocompromised patients. In order to study the humoral immunity against measles in healthcare workers and reveal factors associated with seronegative status, we performed a cross-sectional study by enrolling 847 healthcare workers of the Arkhangelsk Regional Clinical Hospital. Anti-measles virus serum immunoglobulin G antibodies were quantified by using VectorMeasles-IgG ELISA kit (Vector-Best, Russia). According to the manufacturer's recommendations specific IgG anti-measles titer cut-off value higher than 0.18 IU/ml, equal to 0.12—0.17 IU/ml, or lower than 0.12 IU/ml was considered as positive (protective), equivocal, or negative, respectively. Assessing an impact of employee's gender, age, affiliation (department), current position was carried out by using binary logistic regression analysis while analyzing seronegative status of healthcare workers. Study participants dominated by females (92.1%). The median age was 48 (39; 57) years. The employees of somatic departments prevailed (26.7%). It was found that 93.7% of medical workers had concentration of anti-measles antibodies exceeding magnitude of protective titer (above 0.18 IU/ml), 4.4% and 1.9% were measles seronegative and equivocal, respectively. The level of antibodies against measles was associated with age of healthcare workers, but not with gender. All employees older than 60 years were measles seropositive, whereas those younger than 35 or within range 35 to 60 years of age had protective antibody titer in 77% and 95.5% of cases, respectively. The proportion of subjects with seronegative results did not depend on employee's position (doctor, nurse, cleaning worker), but varied a lot between different hospital departments. According to the data of logistic regression, the odds to have a seronegative test result among employees from somatic and remaining departments were 4.4-fold higher. Importantly, the rate of seronegative results was by 10-fold lower in employees born between 1968 and 1984 than those found in subjects born after 1985. On the other hand, subjects older than 60 years of age were seronegative at 50-fold lower rate than those who were under 35. The median concentration of measles immunoglobulin G among vaccinated healthcare workers vs. subjects recovered after natural infection was significantly lower reaching 0.56 IU/ml and 4.2 IU/ml (p < 0.001), respectively. Five-year monitoring showed that titer of measles IgG antibodies decreased by 1.2-1.9-fold (average — 1.5). Thus, a cohort of healthcare workers from multidisciplinary healthcare facility demonstrated that the proportion measles-susceptible subjects was 6.3%. Importantly, age of examined subjects mainly affected seronegative status. Taking into consideration age-related lowered serum antibody level in vaccinated healthcare workers, seroprevalence studies and subsequent revaccination of seronegative people should be performed at least once every 5 years to prevent measles spread in healthcare facilities

Nondispersive solutions to the L2-critical half-wave equation

We consider the focusing $L^2$-critical half-wave equation in one space dimension $$i \partial_t u = D u - |u|^2 u,$$ where $D$ denotes the first-order fractional derivative. Standard arguments show that there is a critical threshold $M_* > 0$ such that all $H^{1/2}$ solutions with $\| u \|_{L^2} < M_*$ extend globally in time, while solutions with $\| u \|_{L^2} \geq M_*$ may develop singularities in finite time. In this paper, we first prove the existence of a family of traveling waves with subcritical arbitrarily small mass. We then give a second example of nondispersive dynamics and show the existence of finite-time blowup solutions with minimal mass $\| u_0 \|_{L^2} = M_*$. More precisely, we construct a family of minimal mass blowup solutions that are parametrized by the energy $E_0 >0$ and the linear momentum $P_0 \in \R$. In particular, our main result (and its proof) can be seen as a model scenario of minimal mass blowup for $L^2$-critical nonlinear PDE with nonlocal dispersion.Comment: 51 page

New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H^+, Li^+, Na^+, K^+, NH_(4)^+, Mg^(2+), Ca^(2+), Cl^−, Br^−, NO_(3)^−, HSO_(4)^−, and SO_(4)^(2−). Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization algorithms. A number of exemplary calculations for systems containing atmospherically relevant aerosol components are shown. Amongst others, we discuss aqueous mixtures of ammonium sulfate with dicarboxylic acids and with levoglucosan. Overall, the new parameterization of AIOMFAC agrees well with a large number of experimental datasets. However, due to various reasons, for certain mixtures important deviations can occur. The new parameterization makes AIOMFAC a versatile thermodynamic tool. It enables the calculation of activity coefficients of thousands of different organic compounds in organic-inorganic mixtures of numerous components. Models based on AIOMFAC can be used to compute deliquescence relative humidities, liquid-liquid phase separations, and gas-particle partitioning of multicomponent mixtures of relevance for atmospheric chemistry or in other scientific fields

Pertussis immunity in pregnant women and factors associated with seronegative status

Despite high level of vaccination coverage, pertussis remains a serious problem of modern medicine. Pertussis cases are registered among infants, adolescents, and adults. Infants younger than three months of age have the highest rate of serious clinical pertussis course. Transplacental transfer of pertussis-specific antibodies induce protection against infection. The available data regarding anti-pertussis antibody level in pregnant women in Russia remain sparce. To evaluate the humoral immunity to Bordetella pertussis in pregnant women and factors associated with seronegative status, we performed a cross-sectional study with 388 participants. SeroPertussis IgG (Israel) ELISA kit was used to quantitate antibodies against pertussis toxin/hemagglutinin. Binary logistic regression analysis was performed to assess factors associated with seronegative status. The median age of the subjects was 30 years old, more than half of which (51.3%) provided no verified pertussis vaccination data so that their children will not receive transplacental anti-infectious immunity. Gestational age was significantly associated with seronegative status. Compared to women tested during the first trimester, participants in the third trimester of pregnancy were more likely to be seronegative against pertussis. The odds of being susceptible rose with increased gestational period (p &lt; 0.01 for linear trend). Age, number of pregnancies and vaccination status revealed no impact on significant differences between seropositive and seronegative subjects. Pertussis booster vaccinations for preschool children, adolescents and healthcare workers dealing with pregnant women and neonates as well as cocoon vaccination strategy and vaccination during pregnancy were necessary to be implemented to protect infants against pertussis

Wilson – Konovalov Disease: Clinical Cases with Different Manifestations and Outcomes

Аim: to describe clinical cases of Wilson – Konovalov disease in pediatric patients.Key points. The first clinical case demonstrates the manifestation of Wilson – Konovalov disease with unexplained mild elevation of aminotransferases at the age of 6 years. Despite the persistent hyperenzymemia, no additional laboratory tests were prescribed. At the age of 10, the patient showed signs of liver failure and neurological symptoms. Laboratory and instrumental examination enabled to diagnose Wilson – Konovalov disease at the stage of liver cirrhosis. The diagnosis was confirmed at the Federal medical center. The diagnosis was delayed and made 4 years after the hyperenzymemia was first revealed. The relief of clinical signs was observed after the orthotopic transplantation of the right lobe of the liver from a living related donor. The patient was under surveillance for 10 years after the transplantation.The second clinical case shows another variant of the course of the Wilson – Konovalov disease manifested as an acute hepatitis. To clarify the etiology of the disease, the patient was hospitalized. In 2 weeks, the patient developed symptoms of acute liver failure, progressive hemorrhagic syndrome, acute hepatic encephalopathy. Death from fulminant hepatitis occurred in 3 weeks after the disease onset after the disease onset.Conclusion. Healthcare workers should be aware of clinical signs of Wilson – Konovalov disease. Screening for the disease is recommended for children with an unexplained increase of liver transaminases, acute liver failure, chronic hepatitis and liver cirrhosis

Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates

We present a soft x-ray angle-resolved photoemission spectroscopy study of the overdoped high-temperature superconductors La$_{2-x}$Sr$_x$CuO$_4$ and La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$. In-plane and out-of-plane components of the Fermi surface are mapped by varying the photoemission angle and the incident photon energy. No $k_z$ dispersion is observed along the nodal direction, whereas a significant antinodal $k_z$ dispersion is identified. Based on a tight-binding parametrization, we discuss the implications for the density of states near the van-Hove singularity. Our results suggest that the large electronic specific heat found in overdoped La$_{2-x}$Sr$_x$CuO$_4$ can not be assigned to the van-Hove singularity alone. We therefore propose quantum criticality induced by a collapsing pseudogap phase as a plausible explanation for observed enhancement of electronic specific heat

Mechanochemical Synthesis of Doped Apatite-type Lanthanum Silicates

In this paper, our results on mechanochemical synthesis of ATLS are summarized. The effect of the dopant type, its parent compound nature and amount of water on the Al and Fe-doped ATLS formation as well as possible phenomenological models of mechanism of apatitetype silicates synthesis are considered. As lanthanum and silicon sources, the La2O3 and SiO2∙nH2O have been taken. As dopant precursors, Fe- and Al-oxides and hydroxides, Fe(HCOO)3, SiO2 impregnated with nitrates have been taken. The apatite formation in the course of milling is studied by XRD, TEM, 29Si and 27Al MAS NMR, IR and UV-Vis spectroscopy. The key role of intermediate La(OH)3 formation, acid-base reactions and double-contact generation in the many-component mixtures due to aluminum or ferrosilicate formation for the rapid MCS of doped ATLS is shown. The doped ATLS formation via the topotactic mechanism was observed in the case of mixtures containing Al(OH)3 and SiO2 impregnated with nitrates. The water presence favours fast passing of acid-base reactions, however a large quantity of water may lead to ATLS formation via the activated mixture amorphization

New Outlook on the Possible Existence of Superheavy Elements in Nature

A consistent interpretation is given to some previously unexplained phenomena seen in nature in terms of the recently discovered long-lived high spin super- and hyper-deformed isomeric states. The Po halos seen in mica are interpreted as due to the existence of such isomeric states in corresponding Po or nearby nuclei which eventually decay by gamma- or beta-decay to the ground states of 210Po, 214Po and 218Po nuclei. The low-energy 4.5 MeV alpha-particle group observed in several minerals is interpreted as due to a very enhanced alpha transition from the third minimum of the potential-energy surface in a superheavy nucleus with atomic number Z=108 (Hs) and atomic mass number around 271 to the corresponding minimum in the daughter.Comment: 8 pages, 8 figures, 5 tables. Paper presented at VII Int. School-Seminar on Heavy Ion Physics, May 27 - June 1, 2002, Dubna, Russi