Synthesis and interaction of terminal unsaturated chemical probes with Mycobacterium tuberculosis CYP124A1

A series of C15–C20 isoprenyl derivatives bearing terminal alkenyl and alkynyl groups were synthesized as possible substrates of the methyl-branched lipid ω-hydroxylase CYP124A1 from Mycobacterium tuberculosis. The interactions of each compound with the enzyme active site were characterized using UV–vis spectroscopy. We found that C10 and C15 analogs bind with similar affinity to the corresponding parent C10 and C15 substrates geraniol and farnesol, respectively. Three analogs (C10-ω-ene, C10-ω-yne, C15-ω-yne) interact with the proximal side of the heme iron by coordinating to the oxygen atom of the ferric heme, as judged by the appearance of typical Type-IA binding spectra. On the other hand, the C15-ω-ene analog interacts with the ferric heme by displacing the bound water that generates a typical Type I binding spectrum. We were unable to detect P450-mediated oxidation of these probes following extended incubations with CYP124A1 in our reconstituted assay system, whereas a control reaction containing farnesol was converted to ω-hydroxy farnesol under the same conditions. To understand the lack of detectable oxidation, we explored the possibility that the analogs were acting as mechanism-based inhibitors, but we were unable to detect time-dependent loss of enzymatic activity. In order to gain insight into the lack of detectable turnover or time-dependent inhibition, we examined the interaction of each compound with the CYP124A1 active site using molecular docking simulations. The docking studies revealed a binding mode where the terminal unsaturated functional groups were sequestered within the methyl-binding pocket, rather than positioned close to the heme iron for oxidation. These results aid in the design of specific inhibitors of Mtb-CYP124A1, an interesting enzyme that is implicated in the oxidation of methyl-branched lipids, including cholesterol, within a deadly human pathogen

Integrating pressure sensor control into semi-solid extrusion 3D printing to optimize medicine manufacturing

Semi-solid extrusion (SSE) is a three-dimensional printing (3DP) process that involves the extrusion of a gel or paste-like material via a syringe-based printhead to create the desired object. In pharmaceuticals, SSE 3DP has already been used to manufacture formulations for human clinical studies. To further support its clinical adoption, the use of a pressure sensor may provide information on the printability of the feedstock material in situ and under the exact printing conditions for quality control purposes. This study aimed to integrate a pressure sensor in an SSE pharmaceutical 3D printer for both material characterization and as a process analytical technology (PAT) to monitor the printing process. In this study, three materials of different consistency were tested (soft vaseline, gel-like mass and paste-like mass) under 12 different conditions, by changing flow rate, temperature, or nozzle diameter. The use of a pressure sensor allowed, for the first time, the characterization of rheological properties of the inks, which exhibited temperature-dependent, plastic and viscoelastic behaviours. Controlling critical material attributes and 3D printing process parameters may allow a quality by design (QbD) approach to facilitate a high-fidelity 3D printing process critical for the future of personalized medicine

Níveis de calcidiol e manutenção da função muscular, capacidade funcional e densidade mineral óssea em uma população espanhola não selecionada.

Introduction: Vitamin D has beneficial effects that supposedly contribute to the maintenance of musculoskeletal function. Objective: To analyze in an unselected population the effect of calcidiol levels on the muscular function of both hands, on the activities of daily living and on changes in bone mineral density (BMD). Material and methods: The cohort of the EVOS study was used, which performed, among others, measurements of muscle strength of grasping both hands, questions related to the difficulty in performing daily activities, densitometric study of the lumbar and hip spine and biochemistry for determination calcidiol levels. Results: Calcidiol values ​​≥20 ng / mL were associated with increased grip muscle strength in both hands. After adjusting for age, sex, BMI and seasonality, calcidiol levels <20 ng / mL were independently associated with decreased muscle grip strength only in the left hand (OR = 2.35, 95% CI 1.03 -5, 38) Likewise, the inability or difficulty in "picking up a book or object on a high shelf" and "getting out of bed" was significantly associated with calcidiol levels <20 ng / mL. Calcidiol levels <20 ng / mL were associated with greater losses of BMD in the femoral neck and in the total hip. These associations were maintained in the multivariate analysis. Conclusions: The maintenance of calcidiol levels ≥20 ng / mL was associated with greater muscle grip strength in the hands, maintenance of daily activities and less loss of BMD in the hip. This study corroborates the usefulness of maintaining adequate levels of vitamin D to maintain musculoskeletal function.Introdução: A vitamina D tem efeitos benéficos que supostamente contribuem para a manutenção da função músculo-esquelética. Objetivo: Analisar em uma população não selecionada o efeito dos níveis de calcidiol na função muscular de ambas as mãos, nas atividades da vida diária e nas alterações na densidade mineral óssea (DMO). Material e métodos: Utilizou-se a coorte do estudo EVOS, que realizou, entre outras, medidas de força muscular de preensão nas duas mãos, questões relacionadas à dificuldade na realização das atividades diárias, estudo densitométrico da coluna lombar e quadril e bioquímica para determinação dos níveis de calcidiol. Resultados: Valores de calcidiol ≥20 ng / mL foram associados ao aumento da força muscular de preensão em ambas as mãos. Após o ajuste para idade, sexo, IMC e sazonalidade, os níveis de calcidiol <20 ng / mL foram associados de forma independente à diminuição da força de preensão muscular apenas na mão esquerda (OR = 2,35, IC 95% 1,03-5, 38) Da mesma forma, a incapacidade ou dificuldade em "pegar um livro ou objeto em uma prateleira alta" e "sair da cama" foi significativamente associada a níveis de calcidiol <20 ng / mL. Níveis de calcidiol <20 ng / mL foram associados a maiores perdas de DMO no colo do fêmur e no quadril total. Essas associações foram mantidas na análise multivariada. Conclusões: A manutenção de níveis de calcidiol ≥20 ng / mL foi associada a maior força de preensão muscular nas mãos, manutenção das atividades diárias e menor perda de DMO no quadril. Este estudo corrobora a utilidade de manter níveis adequados de vitamina D para manter a função músculo-esquelética

Assortment optimisation under a general discrete choice model: A tight analysis of revenue-ordered assortments

The assortment problem in revenue management is the problem of deciding which subset of products to offer to consumers in order to maximise revenue. A simple and natural strategy is to select the best assortment out of all those that are constructed by fixing a threshold revenue $\pi$ and then choosing all products with revenue at least $\pi$. This is known as the revenue-ordered assortments strategy. In this paper we study the approximation guarantees provided by revenue-ordered assortments when customers are rational in the following sense: the probability of selecting a specific product from the set being offered cannot increase if the set is enlarged. This rationality assumption, known as regularity, is satisfied by almost all discrete choice models considered in the revenue management and choice theory literature, and in particular by random utility models. The bounds we obtain are tight and improve on recent results in that direction, such as for the Mixed Multinomial Logit model by Rusmevichientong et al. (2014). An appealing feature of our analysis is its simplicity, as it relies only on the regularity condition. We also draw a connection between assortment optimisation and two pricing problems called unit demand envy-free pricing and Stackelberg minimum spanning tree: These problems can be restated as assortment problems under discrete choice models satisfying the regularity condition, and moreover revenue-ordered assortments correspond then to the well-studied uniform pricing heuristic. When specialised to that setting, the general bounds we establish for revenue-ordered assortments match and unify the best known results on uniform pricing.Comment: Minor changes following referees' comment

Effect of Mono and Di-rhamnolipids on Biofilms Pre-formed by Bacillus subtilis BBK006.

Different microbial inhibition strategies based on the planktonic bacterial physiology have been known to have limited efficacy on the growth of biofilms communities. This problem can be exacerbated by the emergence of increasingly resistant clinical strains. Biosurfactants have merited renewed interest in both clinical and hygienic sectors due to their potential to disperse microbial biofilms. In this work, we explore the aspects of Bacillus subtilis BBK006 biofilms and examine the contribution of biologically derived surface-active agents (rhamnolipids) to the disruption or inhibition of microbial biofilms produced by Bacillus subtilis BBK006. The ability of mono-rhamnolipids (Rha-C10-C10) produced by Pseudomonas aeruginosa ATCC 9027 and the di-rhamnolipids (Rha-Rha-C14-C14) produced by Burkholderia thailandensis E264, and phosphate-buffered saline to disrupt biofilm of Bacillus subtilis BBK006 was evaluated. The biofilm produced by Bacillus subtilis BBK006 was more sensitive to the di-rhamnolipids (0.4 g/L) produced by Burkholderia thailandensis than the mono-rhamnolipids (0.4 g/L) produced by Pseudomonas aeruginosa ATCC 9027. Rhamnolipids are biologically produced compounds safe for human use. This makes them ideal candidates for use in new generations of bacterial dispersal agents and useful for use as adjuvants for existing microbial suppression or eradication strategies

Unusual magneto-optical behavior induced by local dielectric variations under localized surface plasmon excitations

We study the effect of global and local dielectric variations on the polarization conversion rps response of ordered nickel nanowires embedded in an alumina matrix. When considering local changes, we observe a non-monotonous behavior of the rps, its intensity unusually modified far beyond to what it is expected for a monotonous change of the whole refractive index of the embedding medium. This is related to the local redistribution of the electromagnetic field when a localized surface plasmon is excited. This finding may be employed to develop and improve new biosensing magnetoplasmonic devices

Excess cardiovascular mortality associated with cold spells in the Czech Republic

<p>Abstract</p> <p>Background</p> <p>The association between cardiovascular mortality and winter cold spells was evaluated in the population of the Czech Republic over 21-yr period 1986–2006. No comprehensive study on cold-related mortality in central Europe has been carried out despite the fact that cold air invasions are more frequent and severe in this region than in western and southern Europe.</p> <p>Methods</p> <p>Cold spells were defined as periods of days on which air temperature does not exceed -3.5°C. Days on which mortality was affected by epidemics of influenza/acute respiratory infections were identified and omitted from the analysis. Excess cardiovascular mortality was determined after the long-term changes and the seasonal cycle in mortality had been removed. Excess mortality during and after cold spells was examined in individual age groups and genders.</p> <p>Results</p> <p>Cold spells were associated with positive mean excess cardiovascular mortality in all age groups (25–59, 60–69, 70–79 and 80+ years) and in both men and women. The relative mortality effects were most pronounced and most direct in middle-aged men (25–59 years), which contrasts with majority of studies on cold-related mortality in other regions. The estimated excess mortality during the severe cold spells in January 1987 (+274 cardiovascular deaths) is comparable to that attributed to the most severe heat wave in this region in 1994.</p> <p>Conclusion</p> <p>The results show that cold stress has a considerable impact on mortality in central Europe, representing a public health threat of an importance similar to heat waves. The elevated mortality risks in men aged 25–59 years may be related to occupational exposure of large numbers of men working outdoors in winter. Early warnings and preventive measures based on weather forecast and targeted on the susceptible parts of the population may help mitigate the effects of cold spells and save lives.</p

The Rose Bengal Test in Human Brucellosis: A Neglected Test for the Diagnosis of a Neglected Disease

Brucellosis is a highly contagious zoonosis affecting livestock and human beings. The human disease lacks pathognomonic symptoms and laboratory tests are essential for its diagnosis. However, most tests are difficult to implement in the areas and countries were brucellosis is endemic. Here, we compared the simple and cheap Rose Bengal Test (RBT) with serum agglutination, Coombs, competitive ELISA, Brucellacapt, lateral flow immunochromatography for IgM and IgG detection and immunoprecipitation with Brucella proteins. We tested 208 sera from patients with brucellosis proved by bacteriological isolation, 20 contacts with no brucellosis, and 1559 sera of persons with no recent contact or brucellosis symptoms. RBT was highly sensitive in acute and long evolution brucellosis cases and this related to its ability to detect IgM, IgG and IgA, to the absence of prozones, and to the agglutinating activity of blocking IgA at the pH of the test. RBT was also highly specific in the sera of persons with no contact with Brucella. No test in this study outperformed RBT, and none was fully satisfactory in distinguishing contacts from infected patients. When modified to test serum dilutions, a diagnostic titer >4 in RBT resulted in 87.4% sensitivity (infected patients) and 100% specificity (contacts). We discuss the limitations of serological tests in the diagnosis of human brucellosis, particularly in the more chronic forms, and conclude that simplicity and affordability of RBT make it close to the ideal test for small and understaffed hospitals and laboratories

Efficient propagation of systematic uncertainties from calibration to analysis with the SnowStorm method in IceCube

Efficient treatment of systematic uncertainties that depend on a large number of nuisance parameters is a persistent difficulty in particle physics and astrophysics experiments. Where low-level effects are not amenable to simple parameterization or re-weighting, analyses often rely on discrete simulation sets to quantify the effects of nuisance parameters on key analysis observables. Such methods may become computationally untenable for analyses requiring high statistics Monte Carlo with a large number of nuisance degrees of freedom, especially in cases where these degrees of freedom parameterize the shape of a continuous distribution. In this paper we present a method for treating systematic uncertainties in a computationally efficient and comprehensive manner using a single simulation set with multiple and continuously varied nuisance parameters. This method is demonstrated for the case of the depth-dependent effective dust distribution within the IceCube Neutrino Telescope