Reaction rate oscillations during catalytic CO oxidation: A brief overview

It is not the intent here to present a comprehensive review of the dynamic behavior of the catalytic oxidation of CO. This reaction is one of the most widely studied in the field of catalysis. A review paper by Engel and Ertl has examined the basic kinetic and mechanistic aspects, and a comprehensive paper by Razon and Schmitz was recently devoted to its dynamic behavior. Those interested in further study of the subject should consult these reviews and a number of general review papers on catalytic reaction dynamics. The goal is to present a brief overview of certain interesting aspects of the dynamic behavior of this reaction and to discuss a few questions and issues, which are still the subject of study and debate

Phase diagrams of period-4 spin chains consisting of three kinds of spins

We study a period-4 antiferromagnetic mixed quantum spin chain consisting of three kinds of spins. When the ground state is singlet, the spin magnitudes in a unit cell are arrayed as (s-t, s, s+t, s) with integer or half-odd integer s and t (0 <= t < s). The spin Hamiltonian is mapped onto a nonlinear sigma model (NLSM) in a previously developed method. The resultant NLSM includes only two independent parameters originating from four exchange constants for fixed s and t. The topological angle in the NLSM determines the gapless phase boundaries between disordered phases in the parameter space. The phase diagrams for various s and t shows rich structures. We systematically explain the phases in the singlet-cluster-solid picture.Comment: 8 pages (16 figures included

Effet du chlorure de sodium sur la germination de graines de Ricinus communis L.

Ricinus communis L (ricin) figure parmi les espèces du Programme biocarburant au  Sénégal. Sa culture sur des terrains incultes (terres salées) constitue une alternative pour éviter une concurrence sur les terres à vocation agricole. C’est pourquoi le taux de germination (TG) de sept accessions de graines de ricin a été étudié pendant 15 jours sous des concentrations croissantes de NaCl (0; 20; 50; 80; 100; 150 et 200 mM). Les résultats ont montré une large variabilité de tolérance au sel au stade de la germination. Les accessions 3 et 8 ont été très sensibles avec des TG réduits seulement à la concentration 20 mM NaCl. Les accessions 1, 6 et 7 n’ont pas toléré la concentration 50 mM. L’accession 5 n’a toléré que les teneurs &lt; 80 mM. L’accession 4 a germé dans les milieux ≤ 100 mM NaCl. Elle n’a manifesté une perte significative de TG qu’en présence de 150 mM NaCl. Elle a été la moins affectée par l’effet ralentisseur du sel sur la vitesse de germination. Ces résultats permettent de dire que le mode d’action de NaCl sur la germination est de nature osmotique et/ou toxique.Mots clés : Ricin, espèce, biocarburant, tolérance au sel, teneur en sel, Sénégal

Extractive Spectrophotometric Determination of Ce(IV) with p-Anisidine

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HIV and cancer registry linkage identifies a substantial burden of cancers in persons with HIV in India.

We utilized computerized record-linkage methods to link HIV and cancer databases with limited unique identifiers in Pune, India, to determine feasibility of linkage and obtain preliminary estimates of cancer risk in persons living with HIV (PLHIV) as compared with the general population.Records of 32,575 PLHIV were linked to 31,754 Pune Cancer Registry records (1996-2008) using a probabilistic-matching algorithm. Cancer risk was estimated by calculating standardized incidence ratios (SIRs) in the early (4-27 months after HIV registration), late (28-60 months), and overall (4-60 months) incidence periods. Cancers diagnosed prior to or within 3 months of HIV registration were considered prevalent.Of 613 linked cancers to PLHIV, 188 were prevalent, 106 early incident, and 319 late incident. Incident cancers comprised 11.5% AIDS-defining cancers (ADCs), including cervical cancer and non-Hodgkin lymphoma (NHL), but not Kaposi sarcoma (KS), and 88.5% non-AIDS-defining cancers (NADCs). Risk for any incident cancer diagnosis in early, late, and combined periods was significantly elevated among PLHIV (SIRs: 5.6 [95% CI 4.6-6.8], 17.7 [95% CI 15.8-19.8], and 11.5 [95% CI 10-12.6], respectively). Cervical cancer risk was elevated in both incidence periods (SIRs: 9.6 [95% CI 4.8-17.2] and 22.6 [95% CI 14.3-33.9], respectively), while NHL risk was elevated only in the late incidence period (SIR: 18.0 [95% CI 9.8-30.20]). Risks for NADCs were dramatically elevated (SIR &gt; 100) for eye-orbit, substantially (SIR &gt; 20) for all-mouth, esophagus, breast, unspecified-leukemia, colon-rectum-anus, and other/unspecified cancers; moderately elevated (SIR &gt; 10) for salivary gland, penis, nasopharynx, and brain-nervous system, and mildly elevated (SIR &gt; 5) for stomach. Risks for 6 NADCs (small intestine, testis, lymphocytic leukemia, prostate, ovary, and melanoma) were not elevated and 5 cancers, including multiple myeloma not seen.Our study demonstrates the feasibility of using probabilistic record-linkage to study cancer/other comorbidities among PLHIV in India and provides preliminary population-based estimates of cancer risks in PLHIV in India. Our results, suggesting a potentially substantial burden and slightly different spectrum of cancers among PLHIV in India, support efforts to conduct multicenter linkage studies to obtain precise estimates and to monitor cancer risk in PLHIV in India

Seroprevalence of Lyme borreliosis in Finland 50 years ago

ObjectivesLyme borreliosis (LB) is a tick-borne infection common in Europe. In Finland, the LB seroprevalence in the healthy population was 3.9% in 2011. While the present-day seroprevalence of LB is well characterized in several European areas, there are no studies on the seroprevalence of LB before the description of the infection in the late 1970s.MethodsWe used a subset of historical serum samples (n = 994) collected during the Finnish Mobile Clinic Health Survey, a nationwide cross-sectional health survey of the 1960s and 1970s. All samples were screened with Borrelia burgdorferi whole-cell sonicate IgG ELISA. The seropositivity of the samples was further confirmed by the C6 peptide ELISA and recomBead IgG 2.0 bead immunoassay. The association of LB seropositivity with risk factors and with self-reported diseases and symptoms relating to disseminated LB were analysed by logistic regression.ResultsB. burgdorferi IgGs were detected in 199 of 994 analysed samples; hence, the overall seroprevalence was 20.0% (95% confidence interval: 17.6–22.6). The highest seroprevalence was observed in persons aged ≥50 years (165/696), in those currently not working (92/383), and in the regions of South and Central Finland (91/226 and 27/88, respectively). Further, perception of feeling unhealthy (129/197 versus 412/794) was higher among LB-seropositive individuals compared to LB-seronegative participants.ConclusionLB seroprevalence was considerably higher in Finland in the late 1960s and early 1970s than in 2011. This result questions the perception of an unprecedentedly high LB seroprevalence in present-day Europe

Sindbis Virus Strains of Divergent Origin Isolated from Humans and Mosquitoes During a Recent Outbreak in Finland

Sindbis virus (SINV) is a mosquito-borne avian hosted virus that is widely distributed in Europe, Africa, Asia, and Oceania. Disease in humans is documented mainly from Northern Europe and South Africa and associated with genotype I. In 2018 under extremely warm climatic conditions, a small outbreak of 71 diagnosed SINV infections was recorded in Finland. We screened 52 mosquito pools (570 mosquitoes) and 223 human sera for SINV with real-time RT-PCR and the positive samples with virus isolation. One SINV strain was isolated from a pool (n = 13) of genusOchlerotatusmosquitoes and three strains from patient serum samples. Complete genome analysis suggested all the isolates to be divergent from one another and related to previous Finnish, Swedish, and German strains. The study provides evidence of SINV strain transfer within Europe across regions with different epidemiological characteristics. Whether these are influenced by different mosquito genera involved in the transmission remains to be studied.Peer reviewe

Enhanced flight performance by genetic manipulation of wing shape in Drosophila

Insect wing shapes are remarkably diverse and the combination of shape and kinematics determines both aerial capabilities and power requirements. However, the contribution of any specific morphological feature to performance is not known. Using targeted RNA interference to modify wing shape far beyond the natural variation found within the population of a single species, we show a direct effect on flight performance that can be explained by physical modelling of the novel wing geometry. Our data show that altering the expression of a single gene can significantly enhance aerial agility and that the Drosophila wing shape is not, therefore, optimized for certain flight performance characteristics that are known to be important. Our technique points in a new direction for experiments on the evolution of performance specialities in animals