L'ultrasonographie endorectale dans les cancers du rectum [Endorectal ultrasound of rectal cancers].

Endorectal ultrasonography has become the preferred exam to assess the local extent of rectal cancers. From 1990 to 1992, we have examined 28 patients with a rectal cancer. The tumours were classified according to the TNM. The objective of this exam is to identify patients whose tumours have invaded the perirectal fat. These patients are first treated in our clinic by an accelerated hyperfractionated radiotherapy and then operated. The preoperative staging made with the endorectal ultrasound was then compared with the anatomopathologic staging. The depth of the invasion was assessed precisely in 78.5% of cases. The exam's sensitivity to detect the invasion of the perirectal fat was 96% and its specificity 75%. Lymph node involvement was accurately identified in 67.8% of cases with a sensitivity of 81% and a specificity of 50%. This short retrospective study confirms that endorectal ultrasonography is a highly accurate tool for the staging of rectal carcinoma prior to operation and hence to select the patients that can benefit from preoperative irradiation.

Caracterización del sector transporte; marítimo, fluvial y aéreo, como un factor importante para el perfil logístico en Colombia

El Proyecto “Caracterización del sector Transporte; marítimo, fluvial y aéreo, como un factor importante para el perfil logístico en Colombia” es un trabajo que tiene como objeto elaborar un documento, que proporcione toda la información necesaria para comprender y analizar el sector a tratar, teniendo en cuenta los factores que influyeron en el proceso de conformación en cada uno de los sistemas de transporte, dando así un punto de partida para entender la situación actual y las posibles fallas a lo largo de todo el proceso logístico que este implica.

Amyloid-like fibrillogenesis through supramolecular helix-mediated self-assembly of tetrapeptides containing non-coded alpha-aminoisobutyric acid (Aib) and 3-aminobenzoic acid (m-ABA)

Single-crystal X-ray diffraction studies of two terminally protected tetrapeptides Boc-Ile-Aib-Val-m-ABA-OMe (I) and Boc-Ile-Aib-Phe-m-ABA-OMe (II) (Aib = alpha-aminoisobutyric acid; m-ABA = meta-aminobenzoic acid) reveal that they form continuous H-bonded helices through the association of double-bend (type III and I) building blocks. NMR Studies support the existence of the double-bend (type Ill and I) structures of the peptides in solution also. Field emission scanning electron-microscopic (FE-SEM) and high-resolution transmission electron-microscopic (HR-TEM) images of the peptides exhibit amyloid-like fibrils in the solid state. The Congo red-stained fibrils of peptide I and II, observed between crossed polarizers, show green-gold birefringence, a characteristic of amyloid fibrils.

Do designers show categorical perception of typefaces?

Readers need to easily discriminate between different letters, so typefaces are designed to make these differences distinctive. But there is also a uniformity of style within a typeface. These styles are recognised by typographic designers and may be categorised to enable more efficient discrimination among typefaces. The manner in which designers perceive typefaces is explored using the paradigm of Categorical Perception (CP). A continuum of fonts is created by interpolating between two typefaces and two tasks (identification and discrimination) are used to test for CP. As the application of CP to typefaces is a new approach, various methodological issues are pursued. The experiments reveal that the conditions required to demonstrate CP are quite specific and CP was only evident in Times and Helvetica and not Garamond and Bodoni. Possible reasons for this difference are the characteristics of the two typefaces and their context of use. Speculation as to the purpose of CP in non-designers raises the under-researched question of how we identify letters in different typefaces when reading.

The expression of the end-Cenomanian oceanic anoxic event (OAE 2) in the Helvetic Alps

Upper Cenomanian pelagic sediments from the northern Alpine Helvetic fold-and-thrust belt (northern Tethyan margin) coeval with Oceanic Anoxic Event (OAE) 2 are characterized by the temporal persistence of micrite sedimentation and lack of organic carbon-rich layers. We studied an expanded section in the Chrummflueschlucht (east of Euthal, Switzerland), which encompasses the OAE 2 time interval. In order to identify the paleoceanographic and paleoenvironmental conditions during OAE 2 in this part of the northern Tethyan margin, and more specifically to trace eventual changes in nutrient levels and oxic conditions, we investigated the biostratigraphy (planktonic foraminifera), the bulk-rock mineralogy, and measured stable carbon- and oxygen-isotopes, total phosphorus (P) and redox-sensitive trace-element (RSTE) contents. We were able to determine – with some remaining uncertainties – the different planktonic foraminiferal biozones characteristic of the Cenomanian–Turonian boundary interval (Rotalipora cushmani, Whiteinella archaeocretacea and Helvetoglobotruncana helvetica zones). In the lower part of the section (R. cushmani total range zone), the bulk-rock δ13C record shows a long-term increase. Within sediments attributed to the W. archaeocretacea partial range zone, δ13C values reach a maximum of 3.3‰ (peak “a”). In the following the values decrease and increase again to arrive at a plateau with high δ13C values of around 3.1‰, which ends with a peak of 3.3‰ (peak “c”). At the top of the section, in sediments belonging to the H. helvetica total range zone, δ13C values decrease to post-OAE values of around 2.2‰. The last occurrence of R. cushmani is observed just above the positive δ13C shift characterizing OAE 2. P contents display small variations along the section with a long-term decreasing trend towards the top. Before the OAE 2 interval, P values show higher values and relatively good covariation with detrital input, indicating higher nutrient input before OAE 2. In sediments corresponding to the onset of the δ13C positive excursion, P content is marked by a sharp peak probably linked to a slowdown in sedimentation rates and/or the presence of a small hiatus, as is shown by the presence of glauconite and phosphatic grains. In the interval corresponding to OAE 2, P values remain low and increase slightly at the end of the positive shift in the δ13C record (in the H. helvetica total range zone). The average contents of RSTE (U, V, As, Co, Mo and Mn) remain low throughout the section and appreciable RSTE enrichments have not been observed for the sedimentary interval corresponding to OAE 2. No correlation is observed with stratigraphic trends in RSTE contents in organic-rich deeper-water sections. The presence of double-keeled planktonic foraminifera species during most of the Cenomanian/Turonian boundary event is another evidence of relatively well-oxygenated conditions in this part of the northern Tethyan outer shelf. Our results show that the Chrummflueschlucht section corresponds to one of the most complete section for the Cenomanian–Turonian boundary interval known from the Helvetic realm even if a small hiatus may be present at the onset of the δ13C record (peak “a”). The evolution of P contents suggests an increase in input of this nutritive element at the onset of OAE2. However, the trends in RSTE contents and the planktonic foraminifera assemblages show that the Helvetic realm has not been affected by strongly depleted oxygen conditions during OAE 2.

A review of Holocene rainforest ecotonal dynamics at opposite ends of the Amazon - Bolivia versus Colombia

In this review paper, the aim is to compare and contrast fossil pollen evidence for Holocene rainforest ecotonal dynamics at opposite ends of the Amazon basin – the southern ecotone in NE lowland Bolivia versus the northern ecotone in lowland Colombia. During the Holocene, tropical South America experienced major changes in precipitation (Silva Dias et al. 2009). Consideration of Amazonian rainforest dynamics over this time-frame may therefore provide important insights into rainforest responsiveness to climate change.

Crystal structure of garciniaphenone and evidences on the relationship between keto-enol tautomerism and configuration

Garciniaphenone (=rel-(1R,5R,7R)-3-benzoyl-4-hydroxy-8,8-dimethyl-1,7-bis(3-methylbut-2-en-1-yl)bicyclo[3.3.1]non-3-ene-2,9-dione; 1). a novel natural product, was isolated from a hexane extract of Garcinia brasiliensis fruits. The crystal structure of 1 as well as the selected geometrical and Configurational features were compared with those of known related polyprenylated benzophenones. Garciniaphenone is the first representative of polyprenylated benzophenones without a prenyl substituent at C(5). Notably, the absence of a 5-prenyl substituent has an impact on the molecular geometry. The tautomeric form of 1 in the solid state was readily established by a residual-electronic-density map generated by means of a difference Fourier analysis, and there is an entirely delocalized six-membered chelate ring encompassing the keto-enol moiety. The configuration at C(7) was used to rationalize the nature of the keto-enol tautomeric form within 1. The intermolecular array in the network is maintained by nonclassical intermolecular H-bonds.

Crystalline structure of mangiferin, a C-glycosyl-substituted 9H-xanthen-9-one isolated from the stem bark of Mangifera indica

The crystalline structure of mangiferin (= 2-beta-D-glucopyranosyl-1,3,6,7-tetrahydroxy-9H-xanthen-9-one; 1), a biologically active xanthenone C-glycoside, isolated from the stem bark of Mangifera indica (Anacardiaceae), was unambiguously determined by single-crystal X-ray diffraction (XRD). The crystal structure is summarized as follows: triclinic, P1, a = 7.6575(5), b = 11.2094(8), c = 11.8749(8) angstrom, alpha = 79.967(5), beta = 87.988(4), gamma = 72.164(4)degrees, V = 955.3(1) angstrom(3), and Z = 2. The structure also shows two molecules in the asymmetric unit cell and five crystallization H2O molecules. The packing is stabilized by several intermolecular H-bonds involving either the two symmetry-independent mangiferin molecules 1a and 1b, or the H2O ones.

Withanolides from Aureliana fasciculata var. fasciculata

In the first phytochemical study of the Aureliana genus (Solanaceae), two new withanolides, 1 and 2, together with two known sterols, were isolated from the MeOH extract of the leaves of Aureliana fasciculata var. fasciculata. The structures were established as (4S,22R)-16 alpha-acetoxy-5 beta,6 beta-epoxy-4 beta,17 alpha-dihydroxy-1-oxowitha-2,24-dienolide (aurelianolide A) and (4S,22R)-16 alpha-acetoxy-4 beta,17 alpha-dihydroxy-1-oxowitha-2,5,24-trienolide (aurelianolide B). The new compounds possessed the unusual 16 alpha,17 alpha-dioxygenated group and were fully characterized by spectroscopic techniques, including (1)H- and (13)C-NMR (DEPT), as well as 2D-NMR (HMBC, HMQC, (1)H, (1)H-COSY, NOESY) experiments, and HR-MS.

Oleanane Saponins and Glycerogalactolipids from the Leaves of Guapira graciliflora

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure determination of a tetrahydro-beta-carboline of arthropod origin: A novel alkaloid-toxin subclass from the web of spider Nephila clavipes

The orb-web spiders are polyphagous animals in which the web plays a very important role in the capture of preys; oily droplets usually cover the capture-web of the spider Nephila clavipes and seem to be of great importance for prey capture. The knowledge of the chemical composition of these droplets is necessary to understand the function of this adhesive material in web mechanics and prey capture. A novel subclass of spider toxins, tetrahydro-beta-carboline, was identified among the weaponry of compounds present inside of oily droplets. This type of alkaloid is not common among the natural compounds of spider toxins. Apparently, when the prey arthropods get caught by the spider web, their bodies are covered with many adhesive oily droplets, which disrupt delivering the tetrahydro-beta-carboline to the direct contact with the prey integument. Toxicity assays demonstrated a potent lethal effect of the alkaloid toxin to the spider preys; topical applications of the teirahydro-beta-carboline at first caused clear signs of neurotoxicity, followed by the death of preys. The structure of the major component, a tetrahydro-beta-carboline, among the alkaloid toxins was elucidated by means of UV spectrophotometry, ESI mass spectrometry, H-1-NMR spectroscopy, and high-resolution mass spectrometry. The structure of the natural toxin was determined as 1-(2-guanidinoethyl)-1,2,3,4-tetrahydro-6-hydroxymethyl)-beta-carboline; the investigation of the pharmacological properties and neurotoxic actions of this compound may be used in the future as reference for the development of new drugs to be applied at level of pest control in agriculture.

Structure determination of hydroxytrypargine: A new tetrahydro-beta-carboline toxin from the venom of the spider Parawixia bistriata

A new, highly active tetrahydro-p-carboline toxin from the spider Parawixia bistriata, the most-common species of social spider occurring in Brazil, was isolated. The new toxin was identified as 1,2,3,4-tetrahydro-6-hydroxy-beta-carboline (= N-[3-(2,3,4,9-tetrahydro-6-hydroxy-1H-pyrido[3,4-b]indol-1-yl)propyl]guanidine; 3). This type of alkaloid, not common among spider toxins, was found to be the most-potent constituent of the spider's chemical weaponry to kill prey. When P bistriata catch arthropods in their web, they apparently attack their prey in groups of many individuals injecting their venoms. In vivo toxicity assays with 3 demonstrated a potent lethal effect to honeybees, giving rise to clear neurotoxic effects (paralysis) before death. The compound's toxicity (LD50 value) was determined to be ca. 8 ng/g of honeybee. The investigation of the pharmacological properties and neurotoxic actions of 3 may be used in the future for the development of new drugs to be applied for pest control in agriculture.

New antifungal terpenoid glycosides from Alibertia edulis (Rubiaceae)

Phytochemical investigation from the stems of Alibertia edulis led to the isolation and identification of a new iridoid 6 beta-hydroxy-7-epigardoside methyl ester (1) and a new saponin 3 beta-O-[alpha-L-rhamnopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl]-28-O-beta-D-glucopyranoside pomolate (2), along with three known compounds, shanzhiside methyl ester (3), ixoside (4), and 3,4,5-trimethoxyphenyl 1-O-beta-D-apiofuranosyl-(1 -> 6)-O-beta-D-glucopyranoside (5). The structures of 1 and 2 were established on the basis of their spectroscopic data. Iridoid 1 and saponin 2 exhibited moderate inhibitory activities against Candida albicans and C krusei in a dilution assay.

Phenolic Derivatives from Fruits of Dipteryx lacunifera DUCKE and Evaluation of Their Antiradical Activities

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Neural networks in chemosystematic studies of asteraceae: A classification based on a dichotomic approach

This paper describes the application of artificial neural nets as an alternative and efficient method for the classification of botanical taxa based on chemical data (chemosystematics). A total of 28,000 botanical occurrences of chemical compounds isolated from the Asteraceae family were chosen from the literature, and grouped by chemical class for each species. Four tests were carried out to differentiate and classify different botanical taxa. The qualifying capacity of the artificial neural nets was dichotomically tested at different hierarchical levels of the family, such as subfamilies and groups of Heliantheae subtribes. Furthermore, two specific subtribes of the Heliantheae and two genera of one of these subtribes were also tested. In general, the artificial neural net gave rise to good results, with multiple-correlation values R > 0.90. Hence, it was possible to differentiate the dichotomic character of the botanical taxa studied.