Asymmetric Hydrogenation vs Transfer Hydrogenation in the Reduction of Cyclic Imines

A comparison between the two most common reduction approaches for obtaining chiral amines, asymmetric hydrogenation (AH) versus asymmetric transfer hydrogenation (ATH), was accomplished by using iridium complexes based on atropoisomeric diphosphines and cyclic diamines as ligands respectively. Seven substrates, different in electronic and steric properties, were screened applying both reduction methods. For AH the best results in terms of enantioselectivity (e.e. up to 64%) were obtained by using [Ir(COD)(TetraMe-BITIOP)]Cl in the presence of DCDMH as additive. ATH was carried out with [IrCp*(CAMPY)Cl]Cl as catalyst, allowing the obtainment of the products with appreciable e.e. (up to 76%)

Asymmetric Hydrogenation of 1-aryl substituted-3,4-Dihydroisoquinolines with Iridium Catalysts Bearing Different Phosphorus-Based Ligands

Starting from the chiral 5,6,7,8-tetrahydroquinolin-8-ol core, a series of amino-phosphorusbased ligands was realized. The so-obtained amino-phosphine ligand (L1), amino-phosphinite (L2) and amino-phosphite (L3) were evaluated in iridium complexes together with the heterobiaryl diphosphines tetraMe-BITIOP (L4), Diophep (L5) and L6 and L7 ligands, characterized by mixed chirality. Their catalytic performance in the asymmetric hydrogenation (AH) of the model substrate 6,7-dimethoxy-1-phenyl-3,4-dihydroisoquinoline 1a led us to identify Ir-L4 and Ir-L5 catalysts as the most eective. The application of these catalytic systems to a library of dierently substituted 1-aryl-3,4-dihydroisoquinolines aorded the corresponding products with variable enantioselective levels. The 4-nitrophenyl derivative 3b was obtained in a complete conversion and with an excellent 94% e.e. using Ir-L4, and a good 76% e.e. was achieved in the reduction of 2-nitrophenyl derivative 6a using Ir-L5

On the relation between carbonyl stretching frequencies and the donor power of chelating diphosphines in nickel dicarbonyl complexes

The relation between spectroscopic observables and the detailed metal- ligand bonding features in chelation complexes is addressed using both experimental and state-of-the-art theoretical and computational methods. We synthesized and characterized a set of six nickel dicarbonyl complexes of general formula [Ni(CO)(2)(PP)], where PP is an atropoisomeric chelating diphosphine ligand. The analysis of the obtained experimental data and the basicity and oxidative potentials of the free ligands suggests a close relation between the donor ability of the chelating ligand and the carbonyl stretching frequencies observed in the complexes. We then use theory to unravel the detailed mechanisms of chelation-bond formation in terms of partial charge flows between the molecular orbitals of the fragments. By extending the promising, recently published natural orbitals for chemical valence/ charge displacement (NOCV/CD) analysis scheme we provide a thorough, quantitative description of the several charge fluxes following the metal-ligand bond formation and demonstrate that the carbonyl stretching frequencies in the considered complexes selectively respond to the sigma-donation charge flow from the phosphorus lone pairs of the ligands, with the frequency shift being in quantitative correlation with the extent of the ligand-to-metal charge transfer

Toxigenic dinoflagellates and associated toxins in San Jorge Gulf, Argentina

The occurrence of harmful algal blooms (HABs) is a global problem, and particularly in San Jorge Gulf (SJG), Argentina, which supports important fisheries, HABs represent a risk to human health. We studied the diversity and distribution of toxigenic dinoflagellates in the SJG using toxin detection and quantification, and assessed the connections between cell densities, toxins, and oceanographic parameters. Phytoplankton net samples were taken for microscopic and liquid chromatography-tandem mass spectrometry (LC-MSMS) analyses during an expedition aboard R/V Coriolis II in February 2014. Solid phase adsorption toxin tracking (SPATT) devices were also deployed to determine the presence of dissolved lipophilic toxins in seawater. Toxigenic dinoflagellate species and associated toxins showed different distribution patterns in the north and the south SJG. Protoceratium reticulatum and Dinophysis acuminata, together with yessotoxin and pectenotoxins, were predominantly detected in the northern SJG, mainly associated with low-nutrient, warmer waters. By contrast, Alexandrium catenella and paralytic shellfish toxins showed the highest relative abundances in the southern SJG, associated with high-nutrient, low-temperature waters. Cellular toxin content was also differently affected by environmental parameters, highlighting the complexity of HABs in this area. Spirolides were detected by SPATT for the first time in the SJG, suggesting the occurrence of A. ostenfeldii.Facultad de Ciencias Naturales y Muse

Toxigenic dinoflagellates and associated toxins in San Jorge Gulf, Argentina

The occurrence of harmful algal blooms (HABs) is a global problem, and particularly in San Jorge Gulf (SJG), Argentina, which supports important fisheries, HABs represent a risk to human health. We studied the diversity and distribution of toxigenic dinoflagellates in the SJG using toxin detection and quantification, and assessed the connections between cell densities, toxins, and oceanographic parameters. Phytoplankton net samples were taken for microscopic and liquid chromatography-tandem mass spectrometry (LC-MSMS) analyses during an expedition aboard R/V Coriolis II in February 2014. Solid phase adsorption toxin tracking (SPATT) devices were also deployed to determine the presence of dissolved lipophilic toxins in seawater. Toxigenic dinoflagellate species and associated toxins showed different distribution patterns in the north and the south SJG. Protoceratium reticulatum and Dinophysis acuminata, together with yessotoxin and pectenotoxins, were predominantly detected in the northern SJG, mainly associated with low-nutrient, warmer waters. By contrast, Alexandrium catenella and paralytic shellfish toxins showed the highest relative abundances in the southern SJG, associated with high-nutrient, low-temperature waters. Cellular toxin content was also differently affected by environmental parameters, highlighting the complexity of HABs in this area. Spirolides were detected by SPATT for the first time in the SJG, suggesting the occurrence of A. ostenfeldii.Facultad de Ciencias Naturales y Muse

Cascade Reaction by Chemo- and Biocatalytic Approaches to Obtain Chiral Hydroxy Ketones and anti 1,3-Diols

Achemo- andbiocatalytic cascade approach was applied for the stereos elective synthesis of hydroxy ketone sand the corresponding 1,3-diols. A new class of tridentate N,N,Oligands was used with coppe r(II) complexes for the asymmetric b-borylation of a, b-unsaturated compounds. The complex containing ligand L5 emergedas the best performer,and it gave the orga-noborane derivatives with good ee values. The corresponding keto\u2013alcohol compounds were then bioreduced by yeasts. The biotransformation set up with Rhodo Torula rubra allowed (R)- keto\u2013 alcohols and (S, S)-diols to be obtained with up to 99% ee and up to 99% de in favor of the anti enantiomers

The Rotterdam Study: objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in the Netherlands. The study targets cardiovascular, neurological, ophthalmological and endocrine diseases. As of 2008 about 15,000 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in some 600 research articles and reports (see http://www.epib.nl/rotterdamstudy). This article gives the reasons for the study and its design. It also presents a summary of the major findings and an update of the objectives and methods

The Rotterdam Study: 2010 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in close to a 1,000 research articles and reports (see www.epib.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods

The effects of neuroleptics on facial action in schizophrenic patients

This paper describes the influence of neuroleptic therapy on facial action in drug-naive schizophrenics. In a comparative study of medicated and unmedicated schizophrenic patients, the coordinates of 12 small light-reflecting points, attached to subjects' faces, were computer-recorded and analyzed automatically during a semistandardized clinical interview. In addition, facial activity in videotaped interviews was coded using the Facial Action Coding System (FACS). Each sample group comprised of eight patients with the DSMIII- R diagnostic criteria "schizophrenia" or "schizophreniform disorder". Subjects were studied on two occasions, one shortly after admission to the hospital, the other three weeks later. Group I was unmedicated during the first session, whereas group2 was medicated throughout the study. Three weeks after the start of medication, at the second interview, both recording methods showed a reduction in facial activity and facial expression across all subjects in group 1. The facial action of patients in group2, however, remained unchanged.Ziel der vorliegenden Arbeit war die Untersuchung des Einflusses von Neuroleptika auf die Mimik von unmedizierten schizophrenen Patienten. Wiihrend eines halbstandardisierten klinischen Interviews worde die Beweglichkeit von zwolf kleinen, licht-reflektierenden Punkten, die in das Gesicht von medizierten und unmedizierten schizophrenen Patienten geklebt worden, automatisch im Zeitverlauf gemessen. Erganzend wurde der mirnische Ausdruck mit dem Facial Action Coding System (FACS) kodiert, wofiir die Patienten gleichzeitig mit Video aufgenommen worden. Jede der beiden Gruppen bestand aus acht Patienten mit den DSM-IIIR- Diagnosen "Schizophrenie" oder "Schizophrenieforme Storung". Die Patienten worden einmal direkt nach der stationaren Aufnahme und ein zweites Mal nach drei Wochen untersucht. Die Patienten der ersten Gruppe waren zum ersten Zeitpunkt nicht mit Neuroleptika mediziert, wiihrend die der zweiten Gruppe schon zu diesem Zeitpunkt entsprechende Medikamente einnahmen. Es konnte eine Reduktion der mimischen Beweglichkeit des gesamten Gesichtes im Sinne einer neuroleptisch bedingten Hypornimie der primiir Neuroleptika-unbehandelten Patienten bei der zweiten Untersuchung beobachtet werden. Die andere Gruppe Schizophrener, die zu beiden Zeitpunkten mit Neuroleptika behandelt waren, zeigte keine Veriinderung in ihrer mimischen Beweglichkeit

CFD simulations of solid-liquid separation process in modified swirl settling tanks

Przedstawiono wyniki symulacji komputerowych procesu separacji układu ciało stałe-ciecz w nowych konstrukcyjnie osadnikach wirowych. Wykorzystano model burzliwości k-ε i model DPM oprogramowania ASNYS Fluent 19.0. Badania przeprowadzono dla osadników wirowych posiadających króciec wlotowy zanurzony na różnej głębokości oraz przegrodę, której położenie zmieniano. Badania doświadczalne potwierdziły słuszność zastosowania wymienionych modeli. Przedstawiono trajektorie cząstek uzyskane podczas symulacji, które potwierdziły powstawanie ruchu wirowego i prezentowały czas przebywania cząstek ciała stałego wewnątrz osadnika. Konstrukcja o najwyższym stopniu separacji posiadała przegrodę ulokowaną pośrodku między ujściem z króćca wlotowego i wylotowego w osi aparatu.The results of computer simulations of solid-liquid separation in constructional new swirl settling tanks are shown in the paper. The k-e model and DPM models of ANSYS Fluent software 19.0 were used. The studies were carried out for the swirl settling tanks which were characterized by the submerged inlet port situated in a different immersion depth and the baffle with different location inside the tank. Experimental studies confirmed models validity. The particles trajectories obtained in simulations are presented. They confirm the presence of swirl movement and show the residence time of solid particles inside the settling tank. The construction with highest separation efficiency was characterized by the baffle located in tank’s axis and in the middle of inlet and outlet ports