Fluorescent probes of the orientation of myosin regulatory light chains in relaxed, rigor, and contracting muscle.

The orientation of the light-chain region of myosin heads in relaxed, rigor, and isometrically contracting fibers from rabbit psoas muscle was studied by fluorescence polarization. Cysteine 108 of chicken gizzard myosin regulatory light chain (cgRLC) was covalently modified with iodoacetamidotetramethylrhodamine (iodo-ATR). Native RLC of single glycerinated muscle fibers was exchanged for labeled cgRLC in a low [Mg2+] rigor solution at 30 degrees C. Troponin and troponin C removed in this procedure were replaced. RLC exchange had little effect on active force production. X-ray diffraction showed normal structure in rigor after RLC exchange, but loss of axial and helical order in relaxation. In isolated myofibrils labeled cgRLC was confined to the regions of the sarcomere containing myosin heads. The ATR dipoles showed a preference for orientations perpendicular to the fiber axis, combined with limited nanosecond rotational motion, in all conditions studied. The perpendicular orientation preference was more marked in rigor than in either relaxation or active contraction. Stretching relaxed fibers to sarcomere length 4 microns to eliminate overlap between actin- and myosin-containing filaments had little effect on the orientation preference. There was no change in orientation preference when fibers were put into rigor at sarcomere length 4.0 microns. Qualitatively similar results were obtained with ATR-labeled rabbit skeletal RLC

Characteristics of electrohydrodynamic roll structures in laminar planar Couette flow

The behaviour of an incompressible dielectric liquid subjected to a laminar planar Couette flow with unipolar charge injection is investigated numerically in two dimensions. The computations show new morphological characteristics of roll structures that arise in this forced electro-convection problem. The charge and velocity magnitude distributions between the two parallel electrodes are discussed as a function of the top wall velocity and the EHD Rayleigh number, T for the case of strong charge injection. A wide enough parametric space is investigated such that the observed EHD roll structures progress through three regimes. These regimes are defined by the presence of a single or double-roll free convective structure as observed elsewhere (Vazquez et al 2008 J. Phys. D 41 175303), a sheared or stretched roll structure, and finally by a regime where the perpendicular velocity gradient is sufficient to prevent the generation of a roll. These three regimes have been delineated as a function of the wall to ionic drift velocity Uw/kE, and the T number. In the stretched regime, an increase in Uw/kE can reduce charge and momentum fluctuations whilst in parallel de-stratify charge in the region between the two electrodes. The stretched roll regime is also characterised by a substantial influence of Uw/kE on the steady development time, however in the traditional non-stretched roll structure regime, no influence of Uw/kE on the development time is noted

Reducing of industrial atmospheric emissions using electrocyclone

The article is focused on capturing process-related dust at industrial enterprises (in chemical, metallurgical and energy industries). An electrocyclone can be recommended for the purification of gases emitted into the atmosphere from particulates, such as sodium percarbonate (efficiency 97.5%–99.9%), iron-vanadium concentrate (98.0% - 99.9%), fly ash (99.0%–99.9%). However, the fumes from copper-smelting furnaces cannot be purified with high efficiency (less than 50–60%) because of their properties. Using electrocyclone will reduce the amount of aerosol emissions, and in some cases, let the emission reach the values set by standards

The Development of a New Questionnaire to Measure the Burden of Immunoglobulin Treatment in Patients with Primary Immunodeficiencies: The IgBoT-35.

Purpose: To describe the development and psychometric testing of a new questionnaire to measure the burden of immunoglobulin treatment (Ig) from the perspective of patients with primary immunodeficiencies (PID). Patients and Methods: An online, cross-sectional survey was administered to PID patients across 10 countries (nine European and Canada) who were receiving either intravenous (IVIg) or subcutaneous (SCIg) immunoglobulin therapy. The range and distribution of the responses (ie, levels of missing data, floor and ceiling effects), exploratory factor analysis (using factor loadings of 0.4 or greater) and measures of internal consistency reliability (ie, Cronbach's alpha coefficient, inter-item and item-total correlations) were used to identify the domain and item pool. Results: In total, 472 patients completed the questionnaire, of which 395 were included in the analysis (32% underwent IVIg and 67% underwent SCIg). The final instrument contained 34 items across eight domains of treatment burden (time, organisation and planning, leisure and social, interpersonal relationships, employment and education, travel, consequences of treatment and emotional) and an additional Ig treatment burden global question at the end of the measure. All the scales achieved good internal reliability (Cronbach's alpha coefficient ranged from 0.70 to 0.85) and, with the exception of one item exceeded the minimum threshold of 0.35 for item-total correlations. Treatment burden was lower than anticipated across the different treatment routes and countries, although overall was more burdensome for patients undergoing IVIg compared to SCIg treatment. Conclusion: The IgBoT-35 appears to be a reliable, patient-generated questionnaire and may help to identify more individualised and preferred therapies for the PID patient when used in clinical practice. A new survey with a sample of US patients is currently being undertaken to further establish its validity and conceptual model. The overall Ig burden of treatment scores appeared to be low. PID patient preferences are important to guide treatment decisions and ensuring patients receive the right treatment at the right time

An Analysis of the Blockcipher-Based Hash Functions from PGV

Preneel, Govaerts, and Vandewalle (1993) considered the 64 most basic ways to construct a hash function H: {0, 1}*->{0, 1}(n) from a blockcipher E: {0, 1}(n) x {0, 1}(n)->{0,1}(n). They regarded 12 of these 64 schemes as secure, though no proofs or formal claims were given. Here we provide a proof-based treatment of the PGV schemes. We show that, in the ideal-cipher model, the 12 schemes considered secure by PGV really are secure: we give tight upper and lower bounds on their collision resistance. Furthermore, by stepping outside of the Merkle-Damgard approach to analysis, we show that an additional 8 of the PGV schemes are just as collision resistant (up to a constant). Nonetheless, we are able to differentiate among the 20 collision-resistant schemes by considering their preimage resistance: only the 12 initial schemes enjoy optimal preimage resistance. Our work demonstrates that proving ideal-cipher-model bounds is a feasible and useful step for understanding the security of blockcipher-based hash-function constructions

Resistência do plasmodium falciparum ao fansidar, quinina e tetraciclina

Descreve-se pela primeira vez uma cêpa amazônica de Plasmodium falciparum resistente ao Fansidar (pirimetamina mais sulfadoxina) e quinino mais tetraciclina simultaneamente. O paciente, com 13 anos de idade, residia há cinco anos em Ariquemes, Estado de Rondônia, na Amazônia brasileira. A infecção foi curada com dose elevada de cloroquina administrada em dose única intravenosa (IV). É evidenciado o alto valor da cloroquina na cura da malária falciparum resistente, quando administrada em doses maiores que as usadas nos esquemas convencionais de tratamento.For the first time an Amazonian strain of Plasmodium falciparum resistant to FansidarR (pyrimethamine + sulfadoxine) and quinine + tetracycline, taken sequentially is described. This case involves a female patient 13 years old, living for five years in Ariquemes County, State of Rondônia, in the Brazilian Amazon. The infection was cured with a single high dose of chloroquine administered intravenously. The authors point out the high valor of chloroquine in treating falciparum-resistant malaria, especially when given in higher doses than the standard one used for malaria therapy