Synthesis of highly focused fields with circular polarization at any transverse plane

We develop a method for generating focused vector beams with circular polarization at any transverse plane. Based on the Richards-Wolf vector model, we derive analytical expressions to describe the propagation of these set of beams near the focal area. Since the polarization and the amplitude of the input beam are not uniform, an interferometric system capable of generating spatially-variant polarized beams has to be used. In particular, this wavefront is manipulated by means of spatial light modulators displaying computer generated holograms and subsequently focused using a high numerical aperture objective lens. Experimental results using a NA=0.85 system are provided: irradiance and Stokes images of the focused field at different planes near the focal plane are presented and compared with those obtained by numerical simulation.

Regio- and stereoselective microwave-assisted synthesis of 5-alkyl-4-alkenyl-4-phenyl-1,3-oxazolidin-2-ones

Chiral symmetrical alk-2-yne-1,4-diols have been stereoselectively transformed into 5-alkyl-4-alkenyl-4-phenyl-1,3-oxazolidin- 2-ones, which are precursors of quaternary α-amino β-hydroxy acids. The key step was the cyclization of the bis(tosylcarbamates) of 2- phenylalk-2-yne-1,4-diols, easily obtained from the starting chiral diols. These cyclizations were accomplished with complete regioselectivity and up to 92:8 dr in the presence of catalytic amounts of Ni(0) or Pd (II) derivatives under microwave heating.

Stereoselective Synthesis of (-)-Spicigerolide

(-)-Spicigerolide was enantioselectively synthesized from a protected (S)-lactaldehyde. The synthesis of the polyacetylated framework relied on two Zn-mediated stereoselective additions of alkynes to aldehydes as well as a regiocontrolled [3,3]-sigmatropic rearrangement of an allylic acetate. The pyranone moiety was constructed via ring-closing metathesis.

Total synthesis of aeruginazole A

The first total synthesis of Aeruginazole A, prepared via a convergent strategy that involved both solid-phase peptide synthesis and solution phase chemistry and that enabled conservation of the stereochemistry of the intermediates, is reported.

Isolation, structural assignment and total synthesis of Barmumycin

Barmumycin was isolated from an extract of the marine actinomycete Streptomyces sp. BOSC-022A and found to be cytotoxic against various human tumor cell lines. Based on preliminary one- and two-dimensional 1H- and 13C-NMR spectra, the natural compound was initially assigned the structure of macrolactone-type compound 1, which was later prepared by two different routes. However, major spectroscopic differences between isolated barmumycin and 1 led to revision of the proposed structure as E-16. Based on synthesis of this new compound, and subsequent spectroscopic comparison of it to an authentic sample of barmumycin, the structure of the natural compound was indeed confirmed as that of E-16.

Synthesis of Janus compounds for the recognition of G-U mismatched nucleobase pairs

The design and synthesis of two Janus-type heterocycles with the capacity to simultaneously recognize guanine and uracyl in G-U mismatched pairs through complementary hydrogen bond pairing is described. Both compounds were conveniently functionalized with a carboxylic function and efficiently attached to a tripeptide sequence by using solid-phase methodologies. Ligands based on the derivatization of such Janus compounds with a small aminoglycoside, neamine, and its guanidinylated analogue have been synthesized, and their interaction with Tau RNA has been investigated by using several biophysical techniques, including UV-monitored melting curves, fluorescence titration experiments, and 1H NMR. The overall results indicated that Janus-neamine/guanidinoneamine showed some preference for the +3 mutated RNA sequence associated with the development of some tauopathies, although preliminary NMR studies have not confirmed binding to G-U pairs. Moreover, a good correlation has been found between the RNA binding affinity of such Janus-containing ligands and their ability to stabilize this secondary structure upon complexation.

Patient-centered Care in Maternity Services: A Critical Appraisal and Synthesis of the Literature.

BACKGROUND: Patient-centered care (PCC) has been recognized as a marker of quality in health service delivery. In policy documents, PCC is often used interchangeably with other models of care. There is a wide literature about PCC, but there is a lack of evidence about which model is the most appropriate for maternity services specifically. AIM: We sought to identify and critically appraise the literature to identify which definition of PCC is most relevant for maternity services. METHODS: The four-step approach used to identify definitions of PCC was to 1) search electronic databases using key terms (1995-2011), 2) cross-reference key papers, 3) search of specific journals, and 4) search the grey literature. Four papers and two books met our inclusion criteria. ANALYSIS: A four-criteria critical appraisal tool developed for the review was used to appraise the papers and books. MAIN RESULTS: From the six identified definitions, the Shaller's definition met the majority of the four criteria outlined and seems to be the most relevant to maternity services because it includes physiologic conditions as well as pathology, psychological aspects, a nonmedical approach to care, the greater involvement of family and friends, and strategies to implement PCC. CONCLUSION: This review highlights Shaller's definitions of PCC as the one that would be the most inclusive of all women using maternity services. Future research should concentrate on evaluating programs that support PCC in maternity services, and testing/validating this model of care.

Total synthesis of (-)-isoavenaciolide

An enantioselective approach to (-)-isoavenaciolide was achieved starting from 1- undecyn-3-ol. The synthesis relied upon the preparation of a chiral 4-silyloxy-2-alkenylborane by hydroboration of a protected 2,3-allenol and subsequent stereoselective addition to 2- thiophenecarboxaldehyde

Total synthesis of entecavir

Entecavir (BMS-200475) was synthesized from 4-trimethylsilyl-3-butyn-2-one and acrolein. The key features of its preparation are: (i) a stereoselective boron-aldol reaction to afford the acyclic carbon skeleton of the methylenecylopentane moiety; (ii) its cyclization by a Cp2TiCl-catalyzed intramolecular radical addition of an epoxide to an alkyne; and (iii) the coupling with a purine derivative by a Mitsunobu reaction.

Straightforward synthesis of cyclic and bicyclic peptides

Cyclic peptide architectures can be easily synthesized from cysteine-containing peptides with appending maleimides, free or protected, through an intramolecular Michael-type reaction. After peptide assembly, the peptide can cyclize either during the trifluoroacetic acid treatment, if the maleimide is not protected, or upon deprotection of the maleimide. The combination of free and protected maleimide moieties and two orthogonally protected cysteines gives access to structurally different bicyclic peptides with isolated or fused cycles.

Is the presence of an intrathecal synthesis of immunoglobulins associated with neurocognitive impairment in HIV-infected patients?

Worldwide, the incidence of HIV-associated dementia has decreased However, the prevalence of HIV-associated neurocognitive disorders (HAND), mostly the milder forms, i.e. mild neurocognitve disorders (MND) and asymptomatic neurocognitive impairments (ANI) has increased in the combined antiretroviral therapy (cART) era. Indeed, 20% to 60% of well- treated HIV-infected patients, i.e. with undetectable HIV viremia, still present HAND in the cART era. HAND are characterized by psychomotor slowing, memory loss, and attention deficit. Possible explanations for this paradoxical phenomenon encompass: increased survival of HIV- infected patients thank to cART, low grade inflammation of the brain insufficient penetrance of antiretroviral drugs through the blood brain barrier (BBB), or on the contrary, toxic effect of some antiretroviral drugs. These somewhat contradictory hypotheses underline our poor understanding of HAND physiopathology. Here, we aim at determining whether the intrathecal synthesis of immunoglobulins G (IgG), hereafter referred as cerebrospinal fluid oligoclonal band (CSF OB), may help us in better understanding the immunopathogenesis of cognitive disorders. By analogy with other infection, such as syphilis or neuroborreliosis (9, 10), one can assume that, in the case of HIV-infected patients, the CSF OB are directed against HIV proteins (11). Nevertheless, in the case of HIV, the meaning of such CSF OB is unclear. Indeed, it is unknown whether this intrathecal inflammatory reaction is beneficial (viral control) or harmful (brain parenchyma destruction by the different inflammatory factors). Here, we looked at the association between CSF OB and cognitive disorders in HIV-infected patients, hypothesizing that if these CSF OB are protective, one should see an inverse correlation with the presence of cognitive disorders.

Vulnerability of stream biota to climate change in mediterranean climate regions: a synthesis of ecological responses and conservation challenges

Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate change. It is expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human development. In this article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological responses. We also discuss current knowledge gaps and conservation challenges. Expected climate alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and fires. Recent observations, which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental changes. Accurate forecasts of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding hydrology. Long-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate change. Investments should focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Africa. Scientists, policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge.

Synthesis of a tetrahydroimidazo-[2',1':2,3]thiazolo[5,4-c]pyridine derivative with Met inhibitory activity

A straightforward synthesis of the Met antagonist JLK1360 involving an alkylationcyclocondensation process using aminothiazole 1 and nitrophenacyl bromide 2, reduction of the nitro group, and coupling of the resulting tetracyclic aniline 5 with an appropriate N-acyl alanine derivative, is reported.

Synthesis of a tetrahydroimidazo-[2',1':2,3]thiazolo[5,4-c]pyridine derivative with Met inhibitory activity

A straightforward synthesis of the Met antagonist JLK1360 involving an alkylationcyclocondensation process using aminothiazole 1 and nitrophenacyl bromide 2, reduction of the nitro group, and coupling of the resulting tetracyclic aniline 5 with an appropriate N-acyl alanine derivative, is reported.