17 research outputs found

    SEQUENTIAL INDUCTION OF CHIRALITY IN POLY(PHENYLACETYLENE)S

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    Several hierarchical levels of chirality have been detected in functionalized poly(phenylacetylene)s (PPA).1 In this work we have studied the chirality induction throughout these levels in PPA functionalized with phenylglycine methyl ester groups, Fig. 1.2 These pendant groups force the PPA chain to lose its planar all-transoid shape to form helical structures. The chiral seed of the pendants, [(R)- or (S)-], dictates the preferent handedness of the helices, both the internal polyacetylene helical covalent backbone and the external helix formed by the side pendants which forms a complementary helix or counter-helix. In this work, we afford a full assessment of the interconnection between stereocenter and helix sources of chirality and the action of these polymers as chiral templates of other supra-molecular structures with inherited chiral properties. We then used VCD spectroscoy to demonstrate the chiral induction from the stereogenic centers to the backbone helix and from this to the pendant helix, which are largely promoted by two mechanisms: steric effects and hydrogen bonding. In addition, the VCD spectra supported that the helical setup of the pendants induces the solvent DMSO molecules to adopt a solvation helix around the polymer, thus proving how an achiral solvent becomes chirally organized owing to the template effect of the covalent polymer helices. A similar effect was observed in DMSO solutions of the monomeric units. Interestingly, this resulted in opposite helical sense to the one observed in the polymer with identical enantiomeric form.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Variations in the Thickness of the Plantar Fascia After Training Based in Training Race. A Pilot Study

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    Plantar fascia (PF) is a connective tissue made up of mostly type 1 collagen that is subjected to constant loads. This study evaluated the effect of continuous running on tissue stress in the PF by measuring changes in the thickness of the PF using ultrasound scans. It was a cross-sectional study involving 24 runners from the University of Valencia, recruited as volunteers between December 2018 and February 2019. A variety of data was recorded: (age, body mass index, type of footwear, number of workouts per week, KM run per week, sports injuries in the last year, pre and postrace ultrasound PF measurements). There were significant differences in the 3 postrace measurements of the left foot (<0.001). PF thicknesses were measured before and after running, with a minimal average difference of 0.4 mm in the medial and central fascicles, and 0.3 mm in the lateral fascicle. We observed PF thicknesses above 4mm in asymptomatic patients with no signs of vascularisation, proving that increased PF thickness is not the only criterion for diagnosis of plantar fasciitis

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Vibrational Properties of Thiolate-Protected Gold Nanoclusters

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    Transformation from [Au<sub>25</sub>(SCH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>CH<sub>3</sub>)<sub>18</sub>]<sup>0</sup> to Au<sub>28</sub>(SCH<sub>2</sub>CH(CH<sub>3</sub>)Ph)<sub>21</sub> gold nanoclusters: gentle conditions is enough

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    Herein we report the transformation of [Au₂₅(SR)₁₈]⁰ into Au₂₈(SR)₂₁ induced by ligand exchange reaction. In contrast to other reported cluster transformations, which proceed at elevated temperature and large excess of incoming ligands, the transformation reported here occurs under mild conditions (room temperature, very low thiol excess) with a chiral ligand. A difference of one methyl group between incoming and leaving thiol is sufficient to induce the transformation. To the best of our knowledge the Au₂₈(SR)₂₁ cluster has not been isolated before

    Enantiopure, Monodisperse Alleno-acetylenic Cyclooligomers: Effect of Symmetry and Conformational Flexibility on the Chiroptical Properties of Carbon-Rich Compounds

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    Enantiopure, monodisperse alleno-acetylenic cyclooligomers were synthesized. The single-crystal x-ray structures of the cyclic trimer and hexamer were resolved, providing insights into the symmetry of these mols. Electronic CD (ECD), ORD, Raman spectroscopy, and vibrational CD (VCD) data were analyzed with the aid of theor. calcns. This multidimensional approach ultimately provided general guidelines that are useful for designing carbon-rich compds. with intense chiroptical properties

    La desnaturalización de una proteina globular por surfactantes es monotorizada por espectroscopia Raman quiral

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    Desnaturalización de proteínas por surfactantes ha recibido una gran atencion los últimos años debido a sus implicaciones en productos farmacéuticos, cosméticos. A lo largo de esta comunicacion se demuestra la capacidad de la espectroscopia ROA para seguir este procesoUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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