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Asymmetric cross- and self-aldol reactions of aldehydes in water with a polystyrene-supported triazolylproline organocatalyst

  • Llanes, Patricia
  • Sayalero, Sonia
  • Rodríguez-Escrich, Carles
  • Pericàs, Miquel A.
<p> <style type="text/css"> <!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:-536870145 1107305727 0 0 415 0;} @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:-520092929 1073786111 9 0 415 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-parent:""; margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-ansi-language:EN-GB;} p.RSCB01COMAbstract, li.RSCB01COMAbstract, div.RSCB01COMAbstract {mso-style-name:"RSC B01 COM Abstract"; mso-style-unhide:no; mso-style-qformat:yes; mso-style-link:"RSC B01 COM Abstract Char"; margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; text-align:justify; line-height:12.0pt; mso-line-height-rule:exactly; mso-pagination:widow-orphan; font-size:9.0pt; mso-bidi-font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-ansi-language:EN-GB; mso-fareast-language:EN-GB; font-weight:bold; mso-bidi-font-weight:normal; mso-no-proof:yes;} span.06CHeading {mso-style-name:"06 C Heading"; mso-style-priority:1; mso-style-unhide:no; mso-ansi-font-size:9.0pt; mso-bidi-font-size:9.0pt; font-family:"Times New Roman"; mso-ascii-font-family:"Times New Roman"; mso-hansi-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; font-variant:small-caps; mso-font-width:108%; font-weight:bold; mso-bidi-font-weight:normal;} span.RSCB01COMAbstractChar {mso-style-name:"RSC B01 COM Abstract Char"; mso-style-unhide:no; mso-style-locked:yes; mso-style-link:"RSC B01 COM Abstract"; mso-ansi-font-size:9.0pt; mso-fareast-language:EN-GB; font-weight:bold; mso-bidi-font-weight:normal; mso-no-proof:yes;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:11.0pt; mso-ansi-font-size:11.0pt; mso-bidi-font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-ansi-language:EN-GB;} .MsoPapDefault {mso-style-type:export-only; margin-bottom:10.0pt; line-height:115%;} @page WordSection1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.WordSection1 {page:WordSection1;} --> </style> </p> <p class="RSCB01COMAbstract"> <span class="06CHeading"><span lang="EN-GB" style="font-weight:normal">A polystyrene-immobilized triazolylproline has been prepared by a bottom-up approach involving co-polymerization with full regiocontrol. The resulting PS resin swells in water and has been applied to the enantioselective cross-aldol reaction and to the self-aldol reaction of aldehydes under essentially neat conditions, excellent yields and stereoselectivities being recorded.</span></span></p>
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Atomic species identification at the (101) anatase surface by simultaneous scanning tunnelling and atomic force microscopy

  • Stetsovych, Oleksandr
  • Todorovic, Milica
  • Shimizu, Tomoko K.
  • Moreno, Cesar
  • Ryan, James William
  • Perez Leon, Carmen
  • Sagisaka, Keisuke
  • Palomares, Emilio
  • Matolin, Vladimır
  • Fujita, Daisuke
  • Perez, Ruben
  • Custance, Oscar
<div> Anatase is a pivotal material in devices for energy-harvesting applications and catalysis.</div> <div> Methods for the accurate characterization of this reducible oxide at the atomic scale are</div> <div> critical in the exploration of outstanding properties for technological developments. Here</div> <div> we combine atomic force microscopy (AFM) and scanning tunnelling microscopy (STM),</div> <div> supported by first-principles calculations, for the simultaneous imaging and unambiguous</div> <div> identification of atomic species at the (101) anatase surface. We demonstrate that dynamic</div> <div> AFM-STM operation allows atomic resolution imaging within the material&rsquo;s band gap. Based</div> <div> on key distinguishing features extracted from calculations and experiments, we identify</div> <div> candidates for the most common surface defects. Our results pave the way for the understanding</div> <div> of surface processes, like adsorption of metal dopants and photoactive molecules,</div> <div> that are fundamental for the catalytic and photovoltaic applications of anatase, and</div> <div> demonstrate the potential of dynamic AFM-STM for the characterization of wide band gap</div> <div> materials.</div>
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Recent Advances in the Catalytic Preparation of Cyclic Organic Carbonates

  • Martín, Carmen
  • Fiorani,Giulia
  • Kleij, Arjan W.
<p> The catalytic formation of cyclic organic carbonates<br /> (COCs) using carbon dioxide (CO2) as a renewable carbon feed<br /> stock is a highly vibrant area of research with an increasing amount of<br /> researchers focusing on this thematic investigation. These organic<br /> carbonates are highly useful building blocks and nontoxic reagents<br /> and are most commonly derived from CO2 coupling reactions with<br /> oxirane and dialcohol precursors using homogeneous catalysis methodologies. The activation of suitable reaction partners using<br /> catalysis as a key technology is a requisite for efficient CO2 conversion as its high kinetic stability poses a barrier to access<br /> functional organic molecules with added value in both academic and industrial laboratories. Although this area of science has<br /> been flourishing for at least a decade, in the past 2&minus;3 years, significant advancements have been made to address the general<br /> reactivity and selectivity issues that are associated with the formation of COCs. Here, we present a concise overview of these<br /> activities with a primary focus to highlight the most important progress made and the opportunities that catalysis can bring about<br /> when the synthesis of these intermediates is optimized to a higher level of sophistication. The attention will be limited to those<br /> cases in which homogeneous metal-containing systems have been employed because they possess the highest potential for<br /> directed organic synthesis using CO2 as molecular building block. This review discusses examples of exceptional reactivity and<br /> selectivity, taking into account the challenging nature of the substrates that were involved, and mechanistic understanding guiding<br /> the optimization of these protocols is also highlighted.</p>
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Influence of a hyperlipidic diet on the composition of the non-membrane lipid pool of red blood cells of male and female rats.

  • Remesar Betlloch, Xavier
  • Antelo, Arantxa
  • Llivina, Clàudia
  • Albà, Emma
  • Berdié, Lourdes
  • Agnelli, Silvia
  • Arriarán, Sofía
  • Fernández López, José Antonio
  • Alemany, Marià, 1946-
Podeu consultar dades primàries associades a l'article a: http://hdl.handle.net/2445/66010, Background and objectives. Red blood cells (RBC) are continuously exposed to oxidative agents, affecting their membrane lipid function. However, the amount of lipid in RBCs is higher than the lipids of the cell membrane, and includes triacylglycerols, which are no membrane components. We assumed that the extra lipids originated from lipoproteins attached to the cell surface, and we intended to analyse whether the size and composition of this lipid pool were affected by sex or diet. Experimental design. Adult male and femaleWistar rats were fed control or cafeteria diets. Packed blood cells and plasma lipids were extracted and analysed for fatty acids by methylation and GC-MS, taking care of not extracting membrane lipids. Results. The absence of ω3-PUFA in RBC extracts (but not in plasma) suggest that the lipids extracted were essentially those in the postulated lipid surface pool and not those in cell membrane. In cells' extracts, there was a marked depletion of PUFA (and, in general, of insaturation). Fatty acid patterns were similar for all groups studied, with limited effects of sex and no effects of diet in RBC (but not in plasma) fatty acids. Presence of trans fatty acids was small but higher in RBC lipids, and could not be justified by dietary sources. Conclusions. The presence of a small layer of lipid on the RBC surface may limit oxidative damage to the cell outer structures, and help explain its role in the transport of lipophilic compounds. However, there may be other, so far uncovered, additional functions for this lipid pool.
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Road safety determinants: do institutions matter? [WP]

  • Albalate, Daniel, 1980-
  • Yarygina, Anastasiya
Road safety is a global health problem and its severity in developing countries highlights the need for research to address its causes. We explore the effect of institutional variables on road safety, redressing the literature’s failure to consider political institutions as road safety determinants. Specifically, we analyze the effect on traffic accidents and fatalities of different political regimes, electoral rules and forms of government and we control for other factors. By drawing on an international sample of countries taken over a long time-span, we find that democratic institutions are associated with better road safety. The beneficial effects of democratization become apparent after about four years in countries undergoing a regime transition and are also discernible in established democracies that are consolidating their political institutions. Finally, our results suggest that road safety can be characterized as a local public good and that its provision is greater in parliamentary systems.
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Cafeteria diet induce changes in blood flow that are more related with heat dissipation than energy accretion

  • Sabater, David
  • Agnelli, Silvia
  • Arriarán, Sofía
  • Romero, María del Mar
  • Fernández López, José Antonio
  • Alemany, Marià, 1946-
  • Remesar Betlloch, Xavier
Podeu consultar dades primàries associades a l'article a: http://hdl.handle.net/2445/96861, Background. A ``cafeteria'' diet is a self-selected high-fat diet, providing an excess of energy, which can induce obesity. Excess of lipids in the diet hampers glucose utilization eliciting insulin resistance, which, further limits amino acid oxidation for energy. Methods. Male Wistar rats were exposed for a month to ``cafeteria'' diet. Rats were cannulated and fluorescent microspheres were used to determine blood flow. Results. Exposure to the cafeteria diet did not change cardiac output, but there was a marked shift in organ irrigation. Skin blood flow decreased to compensate increases in lungs and heart. Blood flow through adipose tissue tended to increase in relation to controls, but was considerably increased in brown adipose tissue (on a weight basis). Discussion. The results suggest that the cafeteria diet-induced changes were related to heat transfer and disposal.
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Quantitative analysis of rat adipose tissue cell recovery, and non-fat cell volume, in primary cell cultures.

  • Rotondo, Floriana
  • Romero, María del Mar
  • Ho-Palma, Ana Cecilia
  • Remesar Betlloch, Xavier
  • Fernández López, José Antonio
  • Alemany, Marià, 1946-
Podeu consultar dades primàries associades a l'article a: http://hdl.handle.net/2445/102243, Background. White adipose tissue (WAT) is a complex, diffuse, multifunctional organ which contains adipocytes, and a large proportion of fat, but also other cell types, active in defense, regeneration and signalling functions. Studies with adipocytes often require their isolation from WAT by breaking up the matrix of collagen fibres; however, it is unclear to what extent adipocyte number in primary cultures correlates with their number in intact WAT, since recovery and viability are often unknown. Experimental Design. Epididymal WAT of four young adult rats was used to isolate adipocytes with collagenase. Careful recording of lipid content of tissue, and all fraction volumes and weights, allowed us to trace the amount of initial WAT fat remaining in the cell preparation. Functionality was estimated by incubation with glucose and measurement of glucose uptake and lactate, glycerol and NEFA excretion rates up to 48 h. Non-adipocyte cells were also recovered and their sizes (and those of adipocytes) were measured. The presence of non-nucleated cells (erythrocytes) was also estimated. Results. Cell numbers and sizes were correlated from all fractions to intact WAT. Tracing the lipid content, the recovery of adipocytes in the final, metabolically active, preparation was in the range of 70 75%. Cells showed even higher metabolic activity in the second than in the first day of incubation. Adipocytes were 7%, erythrocytes 66% and other stromal (nucleated cells) 27% of total WAT cells. However, their overall volumes were 90%, 0.05%, and 0.2% of WAT. Non-fat volume of adipocytes was 1.3% of WAT. Conclusions. The methodology presented here allows for a direct quantitative reference to the original tissue of studies using isolated cells. We have also found that the ``live cell mass'' of adipose tissue is very small: about 13 mL/g for adipocytes and 2 mL/g stromal, plus about 1 mL/g blood (the rats were killed by exsanguination). These data translate (with respect to the actual ``live cytoplasm'' size) into an extremely high metabolic activity, which make WAT an even more significant agent in the control of energy metabolism.
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Effects of sex and site on amino acid metabolism enzyme gene expression and activity in rat white adipose tissue

  • Arriarán, Sofía
  • Agnelli, Silvia
  • Remesar Betlloch, Xavier
  • Fernández López, José Antonio
  • Alemany, Marià, 1946-
Podeu consultar dades primàries associades a l'article a: http://hdl.handle.net/2445/66872, Background and Objectives.White adipose tissue (WAT) shows marked sex- and diet-dependent differences.However, our metabolic knowledge ofWAT, especially on amino acid metabolism, is considerably limited. In the present study, we compared the influence of sex on the amino acid metabolism profile of the four mainWAT sites, focused on the paths related to ammonium handling and the urea cycle, as a way to estimate the extent ofWAT implication on body amino-nitrogen metabolism. Experimental Design. Adult female and male rats were maintained, undisturbed, under standard conditions for one month. After killing them under isoflurane anesthesia. WAT sites were dissected and weighed. Subcutaneous, perigonadal, retroperitoneal and mesentericWAT were analyzed for amino acid metabolism gene expression and enzyme activities. Results. There was a considerable stability of the urea cycle activities and expressions, irrespective of sex, and with only limited influence of site. Urea cycle was more resilient to change than other site-specialized metabolic pathways. The control of WAT urea cycle was probably related to the provision of arginine/citrulline, as deduced from the enzyme activity profiles. These data support a generalized role of WAT in overall amino-N handling. In contrast, sex markedly affected WAT ammonium-centered amino acid metabolism in a site-related way, with relatively higher emphasis in males' subcutaneousWAT. Conclusions. We found that WAT has an active amino acid metabolism. Its gene expressions were lower than those of glucose-lipid interactions, but the differences were quantitatively less important than usually reported. The effects of sex on urea cycle enzymes expression and activity were limited, in contrast with the wider variations observed in other metabolic pathways. The results agree with a centralized control of urea cycle operation affecting the adipose organ as a whole.
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Effect of verbal task complexity in a working memory paradigm in patients with type 1 diabetes. A fMRI study.

  • Guàrdia Olmos, Joan
  • Gallardo Moreno, Geisa B.
  • Gudayol Ferré, Esteve
  • Peró, Maribel
  • González Garrido, Andrés A.
Podeu consultar dades primàries associades a l'article a: http://hdl.handle.net/2445/109182, Type 1 diabetes (T1D) is commonly diagnosed in childhood and adolescence, and the developing brain has to cope with its deleterious effects. Although brain adaptation to the disease may not result in evident cognitive dysfunction, the effects of T1D on neurodevelopment could alter the pattern of BOLD fMRI activation. The aim of this study was to explore the neural BOLD activation pattern in patients with T1D versus that of healthy matched controls while performing two visuospatial working memory tasks, which included a pair of assignments administered through a block design. In the first task (condition A), the subjects were shown a trial sequence of 3 or 4 white squares positioned pseudorandomly around a fixation point on a black background. After a fixed delay, a second corresponding sequence of 3 or 4 red squares was shown that either resembled (direct, 50%) or differed from (50%) the previous stimulation order. The subjects were required to press one button if the two spatial sequences were identical or a second button if they were not. In condition B, the participants had to determine whether the second sequence of red squares appeared in inverse order (inverse, 50%) or not (50%) and respond by pressing a button. If the latter sequence followed an order distinct from the inverse sequence, the subjects were instructed to press a different button. Sixteen patients with normal IQ and without diabetes complications and 16 healthy control subjects participated in the study. In the behavioral analysis, there were no significant differences between the groups in the pure visuo-spatial task, but the patients with diabetes exhibited poorer performance in the task with verbal stimuli (p < .001). However, fMRI analyses revealed that the patients with T1D showed significantly increased activation in the prefrontal inferior cortex, subcortical regions and the cerebellum (in general p < .001). These different activation patterns could be due to adaptive compensation mechanisms that are devoted to improving efficiency while solving more complex cognitive tasks.
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In rats fed high-energy diets, taste, rather than fat content, is the key factor increasing food intake: a comparison of a cafeteria and a lipid-supplemented standard diet

  • Oliva Lorenzo, Laia
  • Aranda, Tània
  • Caviola, Giada
  • Fernández-Bernal, Anna
  • Alemany, Marià, 1946-
  • Fernández López, José Antonio
  • Remesar Betlloch, Xavier
Podeu consultar dades primàries associades a l'article a: http://hdl.handle.net/2445/111074, Background. Food selection and ingestion both in humans and rodents, often is a critical factor in determining excess energy intake and its related disorders. Methods. Two different concepts of high-fat diets were tested for their obesogenic effects in rats; in both cases, lipids constituted about 40% of their energy intake. The main difference with controls fed standard lab chow, was, precisely, the lipid content. Cafeteria diets (K) were self-selected diets devised to be desirable to the rats, mainly because of its diverse mix of tastes, particularly salty and sweet. This diet was compared with another, more classical high-fat (HF) diet, devised not to be as tasty as K, and prepared by supplementing standard chow pellets with fat. We also analysed the influence of sex on the effects of the diets. Results. K rats grew faster because of a high lipid, sugar and protein intake, especially the males, while females showed lower weight but higher proportion of body lipid. In contrast, the weight of HF groups were not different from controls. Individual nutrient's intake were analysed, and we found that K rats ingested large amounts of both disaccharides and salt, with scant differences of other nutrients' proportion between the three groups. The results suggest that the key differential factor of the diet eliciting excess energy intake was the massive presence of sweet and salty tasting food. Conclusions. The significant presence of sugar and salt appears as a powerful inducer of excess food intake, more effective than a simple (albeit large) increase in the diet's lipid content. These effects appeared already after a relatively short treatment. The differential effects of sex agree with their different hedonic and obesogenic response to diet.
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