Search

Organic semiconductors with well-defined architectures pose a suitable alternative to amorphous silicon-based inorganic semiconductors. Encouraged by the development of organic semiconductors based on columnar liquid crystals, herein, we report on a family of C3-symmetric star-shaped mesogens based on triphenylamine (TPA), a functional unit with strong electron donor character. Highly stable columnar phases with high hole mobility values were obtained out of this nonplanar functional unit, and this was achieved by using flexible amide spacers to join the TPA units to a tris(triazolyl)triazine (T) star-shaped core, allowing the formation of intermolecular hydrogen bonds. The presence of hydrogen bonds results in a stabilization of the columnar architectures either in bulk or in the presence of solvents by reinforcing π-stacking and van der Waals interactions, as deduced by Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) studies. Furthermore, the introduction of a stereogenic center in the flexible spacer prompts the formation of chiral aggregates in the liquid crystal state and in the organogel formed in 1-octanol, as demonstrated by circular dichroism spectroscopy.

In vitro–in vivo extrapolation (IVIVE) allows prediction of clinical outcomes across populations from in vitro data using specific scalars tailored to the biologic characteristics of each population. This study experimentally determined scalars for patients with varying degrees of nonalcoholic fatty liver disease (NAFLD), ranging from fatty liver to nonalcoholic steatohepatitis (NASH) and cirrhosis. Microsomal, S9, and cytosol fractions were extracted from 36 histologically normal and 66 NAFLD livers (27 nonalcoholic fatty liver [NAFL], 13 NASH, and 26 NASH with cirrhosis). Corrected microsomal protein per gram liver (MPPGL) progressively decreased with disease severity (26.8, 27.4, and 24.3 mg/g in NAFL, NASH, and NASH/cirrhosis, respectively, compared with 35.6 mg/g in normal livers; ANOVA, P< 0.001). Homogenate, S9, and cytosolic protein showed a consistent trend of decline in NASH/cirrhosis relative to normal control (post-hoc ttest, P< 0.05). No differences across the groups were observed in homogenate, S9, cytosolic, and microsomal protein content in matched kidney samples. MPPGL-based scalars that combine protein content with liver size revealed that the reduction in MPPGL in NAFL and NASH was compensated by the reported increase in liver size (relative scalar ratios of 0.96 and 0.99, respectively), which was not the case with NASH/cirrhosis (ratio of 0.63), compared with healthy control. Physiologically based pharmacokinetics-informed global sensitivity analysis of the relative contribution of IVIVE scalars (hepatic CYP3A4 abundance, MPPGL, and liver size) to variability in exposure (area under the curve) to three CYP3A substrates (alprazolam, midazolam, and ibrutinib) revealed enzyme abundance as the most significant parameter, followed by MPPGL, whereas liver volume was the least impactful factor.SIGNIFICANCE STATEMENTNonalcoholic fatty liver disease-specific scalars necessary for extrapolation from in vitro systems to liver tissue are lacking. These are required in clearance prediction and dose selection in nonalcoholic fatty liver and steatohepatitis populations. Previously reported disease-driven changes have focused on cirrhosis, with no data on the initial stages of liver disease. The authors obtained experimental values for microsomal, cytosolic, and S9 fractions and assessed the relative impact of microsomal scalars on predicted exposure to substrate drugs using physiologically based pharmacokinetics.

Gene therapy has become a relevant tool in the biomedical field to treat or even prevent some diseases. The effective delivery of genetic material into the cell remains a crucial step to succeed in this purpose. In the search for efficient non-viral vectors, a series of amino-terminated dendronized hyperbranched polymers (DHPs) of different generations based either on bis-MPA or bis-GMPA have been designed. All of them have demonstrated an accurate ability to complex two types of genetic materials, a plasmid DNA and a siGFP, yielding dendriplexes. Moreover, some of them have proved to be able to deliver the genetic material inside the cells, resulting in the effective accomplishment of the desired genetic modification and improving the activity of some commercial transfection reagents. Different cell lines, including cancer and mesenchymal stem cells, have been studied here to evaluate the ability of DHPs as vectors for transfection. Treatments based on mesenchymal stem cells are gaining importance due to their pluripotency. Thus, it is of special relevance to introduce a genetic modification into a mesenchymal cell line as it allows it to act over a wide spectrum of tissues after inducing cellular differentiation.

Objective: To determine if selective newborn cord blood testing (NCBT) could contain costs without increasing morbidity of hemolytic disease of the newborn (HDN). Design: A national telephone survey confirmed the common practice of routine blood type and Coombs' NCBT. Two 12-month study arms, retrospective and prospective, were conducted. Hemolytic disease of the newborn was studied retrospectively under an unrestricted NCBT policy. Then, HDN was studied after a policy change that restricted NCBT to patients in newborn intensive care units and normal newborns with clinical jaundice or Rh-negative mothers, and/or positive maternal antibody screenings, or unavailable maternal blood testing. Participants: All newborns (N=8501) at the MetroHealth Medical Center, Cleveland, Ohio, were studied (retrospective arm, all 1989 admissions; prospective arm, all July 1990 to June 1991 admissions). Outcome Measures: Blood type and Coombs' NCBT, maternal blood type and antibody screening, Hobel risk scores for clinical severity of newborn hospitalization, duration of hospitalizations, and peak serum bilirubin levels. Results: No quantitative or qualitative increases in morbidity from jaundice were detected by retrospective analysis with unrestricted NCBT, or prospectively after selective testing on 4498 newborns. Each study arm resulted in 15 readmissions for jaundice; these included two patients with ABO HDN. Furthermore, selective testing resulted in performance of NCBTs on only 390 infants in the 'normal' nursery (24% of the original sample). Estimates projected on 1991 US births (4 111 000) showed that selective NCBT offers potential yearly savings above $30.8 million of patient charges, savings above $11.3 million of hospital costs, and the reassignment of more than 112 personnel full-time equivalents. Conclusion: Selective NCBT decreases the use of resources and costs without apparent additional patient morbidity from HDN. (Arch Pediatr Adolesc Med. 1995;149:1147-1151), Ceasing routine testing of the newborn's umbilical cord blood to ascertain ABO or Rh incompatibility does not appear to have any effect on diagnosis of hemolytic disease of the newborn (HDN) and would save money. HDN is severe jaundice due to the mother's antibodies destroying the child's red blood cells. All babies born during a one-year period at a medical referral center had routine determination of umbilical cord blood type and a Coomb's test, whereas in a subsequent year, only at-risk infants were tested. This policy reduced the number of blood samples tested from 1,593 to 1,048, a 76% reduction. Fifteen children required readmission for neonatal jaundice, and there were two readmissions for HDN due to ABO incompatibility during each time period. No differences were found in length of hospitalization for jaundice nor in peak jaundice levels. Selective testing saved the hospital $8,745 in hospital costs, $23,759 in patient charges, and 180 hours of technician time.

The Spanish National Hip Fracture Registry (or Registro Nacional de Fractura de Cadera, RNFC) is a database of hip fracture patients admitted to Spanish hospitals. Its goals include assessment and continuous improvement of the care process.

Anaemia is a very common condition in elderly patients with hip fracture. The side effects of blood transfusions are well known, and further research on potential alternative therapies is needed.

Two-dimensional (2D) crystallization behaviors of A-TPCn(n= 4, 6, 10), T3C4, and hydrogen-bonded complexes T3C4@TPCn(n= 4, 6, 10) are investigated by means of scanning tunneling microscope (STM) observations and density functional theory (DFT) calculations. The STM observations reveal that A-TPC4, A-TPC10, and T3C4self-organize into dumbbell-shaped structures, well-ordered bright arrays, and zigzag structures, respectively. Interestingly, T3C4@TPC10fails to form the cage-ball structure, whereas T3C4@TPC4and T3C4@TPC6co-assemble into cage-ball structures with the same lattice parameters. The filling rates of the balls of these two kinds of cage-ball structures depend heavily on the deposition sequence. As a result, the filling rates of the cages in T3C4/A-TPCn(n= 4, 6) with deposition of T3C4anterior to A-TPCnare higher than those in A-TPCn/T3C4(n= 4, 6) with the opposite deposition sequence. Furthermore, lattice defects formed by T3C4coexist with the cage-ball structures. Moreover, the similar energy per unit area of lattice defects (−0.101 kcal mol–1Å–2) and the two cage-ball networks (−0.194 and −0.208 kcal mol–1Å–2, respectively), illustrating the similar stabilities of lattice defects and cage-ball networks, demonstrates the rationality of lattice defects. Combining STM investigations and DFT calculations, this work could provide a useful approach to investigate the 2D crystallization mechanisms of supramolecular liquid crystals on surfaces.

Biomaterials for antimalarial drug transport still need to be investigated in order to attain nanocarriers that can tackle essential issues related to malaria treatment, e.g.complying with size requirements and targeting specificity for their entry into Plasmodium-infected red blood cells (pRBCs), and limiting premature drug elimination or drug resistance evolution. Two types of dendritic macromolecule that can form vehicles suitable for antimalarial drug transport are herein explored. A new hybrid dendritic-linear-dendritic block copolymer based on Pluronic® F127 and amino terminated 2,2′-bis(glycyloxymethyl)propionic acid dendrons with a poly(ester amide) skeleton (HDLDBC-bGMPA) and an amino terminated dendronized hyperbranched polymer with a polyester skeleton derived from 2,2′-bis(hydroxymethyl)propionic acid (DHP-bMPA) have provided self-assembled and unimolecular micelles. Both types of micelle carrier are biocompatible and exhibit appropriate sizes to enter into pRBCs. Targeting studies have revealed different behaviors for each nanocarrier that may open new perspectives for antimalarial therapeutic approaches. Whereas DHP-bMPA exhibits a clear targeting specificity for pRBCs, HDLDBC-bGMPA is incorporated by all erythrocytes. It has also been observed that DHP-bMPA and HDLDBC-bGMPA incorporate into human umbilical vein endothelial cells with different subcellular localization, i.e.cytosolic and nuclear, respectively. Drug loading capacity and encapsulation efficiencies for the antimalarial compounds chloroquine, primaquine and quinacrine ranging from 30% to 60% have been determined for both carriers. The resulting drug-loaded nanocarriers have been tested for their capacity to inhibit Plasmodiumgrowth in in vitroand in vivoassays.

Evaluar los resultados asistenciales y la repercusión económica de la intervención geriátrica en pacientes mayores de 75 años con fractura de cadera en fase aguda.

La infección por Clostridium difficile es actualmente la principal causa de enfermedad gastrointestinal de origen nosocomial. Su prevalencia en la población anciana es superior por reunirse en este grupo etario gran cantidad de factores de riesgo como son comorbilidad, frecuente exposición al medio sanitario o residencial, inmunosenescencia y mayor consumo de antibióticos y antiácidos. En los últimos años, las técnicas diagnósticas han mejorado notablemente, lo que podría implicar un incremento de diagnósticos. Las nuevas pautas de consenso de expertos proponen la estratificación de la situación clínica del paciente en el momento del diagnóstico para la elección del tratamiento óptimo. Recientemente se han incluido en las guías clínicas nuevas opciones terapéuticas como la flidaxomicina o el trasplante de materia fecal con resultados alentadores, sobre todo para el control de las frecuentes recurrencias.

Introduction:Nanostructured lyotropic liquid crystal particles (LLC NPs) have proven to be extremely useful tools for applications in drug delivery. These structured nanoparticles are formed by amphiphilic molecules and contain internal water channels, which are not in contact with external water, and where polar drugs can situate; on the other hand, apolar drugs can be loaded in the lipophilic part of the structure and the amphiphilic drugs can locate at the polar/apolar interfaces.Areas covered:A revision of the most relevant results published in the field of LLC NPs has been made. The first section discusses the most common compounds used in these nanoparticles and their preparation and characterization. A summary of recent and relevant results including the composition and type of nanoparticles used, the illness treated, the administration via and some special features in each case have been summarized in a table.Expert opinion:LLC NPs are highly versatile drug delivery systems, which can be applied by topical, oral and intravenous treatments. Especially relevant is their use for the release of anticancer drugs, biomolecules and vaccines. Nevertheless a number of critical points need to be solved in order to attain practical applications.

No Abstract

No Abstract

The preparation of optically active atropoisomeric polymers which present chiral backbones, thanks to induction during their synthesis from stereogenic centers, located far away from the skeleton is possible, thanks principally to semirigid conformations of the promesogenic spacers between them. The result is that chiral “information” can be passed as far as 21 Å from the asymmetric center to the carbon atom that forms the polymeric chain in poly(isocyanide)s. The sense of chiral induction in these conformationally rigid polymers parallels the helical sense of the cholesteric phases, as well as to the helical senses of chiral smectic C phases, induced by the monomers in nematic and smectic C phases, respectively. All these phenomena obey the odd–even rules proposed for chiral sense changes in these liquid crystalline phases. Noncovalent interactions play an important part in the induction process, in which steric arguments can be used to justify the inductions observed. The methodology can be used to prepare macromolecules, which display switching behavior upon thermal or electrochemical stimulus. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3161–3174, 2006

The synthesis and characterization of the mesomorphic and dielectric properties of new imine-based liquid crystalline compounds that exhibit tilted SmC phases is reported. The presence of an imino linkage within the mesogenic nucleus of these compounds is significant due to the ability of benzaldimines to coordinate to metals. Complexation to a divalent metal such as Pdii has been studied in order to assess the effects of antiparallel dimerization of organic ligands, through metal-coordination, on the appearance of antiferroelectric order in the mesophase. An organometallic palladiumii complex has been prepared and this shows antiferroelectric behaviour over the whole range of the tilted smectic mesophase. Structure–activity studies have also been carried out by varying structural elements in the composition of the ligands. The changes include the disposition of the linking groups within the mesogenic core, and presence of a lateral hydroxy group.

The synthesis and characterization of the mesomorphic and dielectric properties of new imine-based liquid crystalline compounds that exhibit tilted SmC* phases is reported. The presence of an imino linkage within the mesogenic nucleus of these compounds is significant due to the ability of benzaldimines to coordinate to metals. Complexation to a divalent metal such as Pd(ii) has been studied in order to assess the effects of antiparallel dimerization of organic ligands, through metal-coordination, on the appearance of antiferroelectric order in the mesophase. An organometallic palladium(ii) complex has been prepared and this shows antiferroelectric behaviour over the whole range of the tilted smectic mesophase. Structure–activity studies have also been carried out by varying structural elements in the composition of the ligands. The changes include the disposition of the linking groups within the mesogenic core, and presence of a lateral hydroxy group.

Hexacatenar chiral oxazoline complexes were prepared in a stereospecific synthesis. Metals (Pd, Ni, Cu, Zn), lateral alkoxy chains (OC₆H₁₃, OC₁₂H₂₅), sterically demanding alkyl groups (CH₃, C₄H₉) on the chiral rigid centre and the number of nuclei incorporated in the complex core (mononuclear, orthopalladated dinuclear) were varied in order to achieve supramolecular organization of the phasmid-like molecules in liquid crystal phases. Mesomorphic properties were not observed in neat materials, but phase diagrams of binary mixtures with TNF demonstrate that steric repulsion can be overcome by intercalation of the electron-acceptor TNF. In spite of the presence of six lateral chains, SmA phases were found exclusively. The structures of the SmA phases were found to have additional order with respect to SmA phases formed by calamitic molecules. Further examination of the complexes in host nematic materials demonstrated their use as chiral dopants to induce cholesteric LC phases.

Chiral columnar liquid crystals have recently appeared as a promising new type of ferroelectric materials. To date, all the columnar liquid crystals that have been reported to show ferroelectric switching consist of organic compounds. However, metal‐containing liquid crystals open this field to a significant number of new structures and offer the possibility of adding to the ferroelectric behavior other properties inherent to the presence of metals in the structure, such as magnetism, as well as the use of new methods of characterization (EPR, synchrotron radiation, etc.). The potential of columnar metal‐containing liquid crystals as ferroelectric materials has been demonstrated even though only a few organic columnar ferroelectric liquid crystals have been described. As a first approach to this type of material, this concepts article describes the results obtained with chiral metal β‐diketonates that show ferroelectric switching in the columnar mesophase. It has been shown that these materials have a helical columnar arrangement in the mesomorphic state, and a chiral superstructure has been proposed from circular dichroism studies. This type of supramolecular structure plays a fundamental role in the ferroelectric properties of these compounds. The discussion is mainly focused on the strategy employed for the molecular design, and on the interpretation of the mesophase structure and the electrooptic effect. The use of a diverse range of techniques, both those commonly used in the field of liquid crystals and those that are more specific will be highlighted, and the principles of these specific techniques are summarized together with a justification of their applicability to this study.

Creation of helical SmC* and Ch mesophases has been achieved by means of metal ion complexation by chiral isocyanide ligands, which have already proven their ability to induce high optical activity in helical synthetic polymers. Thus, from unstable isocyanide compounds with a mesogenic core derived from phenyl benzoate, five stable complexes have been prepared. Four palladium(II) complexes have been obtained with different chiral tails and, in one case, with a three-ring mesogenic core. Their corresponding SmC* phases have been studied in terms of their ferroelectric properties. High Ps values have been found for complexes derived from (S)-octan-2-ol: 93 4;nC 4;cm–2 for I2Pd(C8*)2 and 59 4;nC 4;cm–2 for I2Pd(COOPhC8*)2. A gold(I) complex with (R)-2-octyl as the chiral tail is presented as the first SmC* gold(I) complex whose ferroelectric behaviour has been studied. Indeed, the complex has been used as a chiral dopant in a binary mixture, the Ps value of which has been estimated.

A biotin-enhanced enzyme immunoassay (EIA) for respiratory syncytial virus (RSV) antigen detection (TESTPACK RSV®) was prospectively compared with virus isolation in cell culture and immunofluorescence. Of 156 nasopharyngeal swab specimens from infants with respiratory symptoms, 81 (52) yielded RSV in culture. Compared with culture the sensitivity of the EIA was 95 and specificity was 92; the specificity increased to 97 with a blocking assay. Compared with immunofluorescence the sensitivity of EIA was 92 and specificity was 93. In order to assess the performance of TESTPACK RSV® as a bedside test, nasopharyngeal swabs from 49 children were tested by EIA at the bedside by housestaff and by immunofluorescence in the laboratory; the sensitivity of the EIA was lower (78) while specificity remained high (95). Inclusion of older children may have resulted in diminished sensitivity. The TESTPACK RSV® is a simple, rapid test that performs well and is easily adaptable to an office setting. Further evaluation of the test in older children may be required.

Possessing excellent processibility on silicon integrated circuits and a thermodynamically stable polar supermolecular structure, chiral smectic C (C*) ferroelectric liquid crystals (FLCs) are promising materials for use in ultra-fast (>500 MHz) integrated electro-optic modulators. In order to realize this promise, however, it is necessary to obtain FLC materials with values of the electronic second order nonlinear optical (NLO) susceptibility χ(2) larger than have been reported to date. One way to achieve this goal is to obtain orientation of “large β” organic functional arrays, composed of two rings with a conjugating spacer unit, along the polar axis in the C* phase. Such long molecular groupings, however, typically orient along the director in LC phases, normal to the C* polar axis. We present herein the results of the initial investigation of an approach for achieving large χ(2) in FLCs. In this case orientation of the prototypical large β chromophore found in the dye Disperse Red 1 (DR1) is achieved by incorporation of the chromophore into a side-by-side dimer structure. Characterization of C* mixtures incorporating the new dopant at concentrations up to 30% by weight shows that indeed the DR1 chromophore can be oriented along the polar axis in FLCs with a moderate degree of polar stereocontrol.

We have recently reported the first FLCs designed specifically for large second order nonlinear optical (NLO) susceptibility χ(2); a series of o-nitro-1-methylheptyloxy biphenylbenzoates and phenyl biphenylcarboxylates. Properties of a stable room-temperature C* mixture of two such components (1:1 W316/W317 = MX5679) are presented. The nonlinear susceptibility, as evidenced by the Type 1 eeo deff for second harmonic generation (SHG) from 1,064 nm light for MX5679 is indeed large relative to other FLCs which have been evaluated for χ(2) (deff (ZLI3654) = 0.0016 pm/V, deff (SCE9) = 0.0037 pm/V, deff (MX5679) = 0.16 pm/V). The synthesis and some properties of second-generation FLCs designed for NLO applications is also described.

The synthesis and characterization of a series of tetrathiafulvalenes (1–3) bearing a different number of 4′-cyanobiphenyl-4-yloxy side groups is reported. Compound 3 exhibits a nematic and a smectic A mesophase. In the smectic A phase a peculiar local biaxial order due to the unconventional molecular structure is proposed. A charge-transfer salt derived from 3, namely 3·I5 , also shows mesogenic behaviour.

No Abstract.

Diastereoselectivity in the polymerisation of isocyanides has been observed to be operating over approximately 2 nm, which separates the reactive group from the stereogenic centre, as revealed by circular dichroism spectroscopy.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The synthesis, electrochemical and mesomorphic properties of 4,5-ethylenedithio-4′-[2-(perfluorohexyl)ethoxycarbonyl] tetrathiafulvalene are reported. This compound is the first semifluorinated mesogenic tetrathiafulvalene derivative.