Closed Aromatic Tubes-Capsularenes.

In this study, we describe a synthetic method for incorporating arenes into closed tubes that we name capsularenes. First, we prepared vase-shaped molecular baskets 4-7. The baskets comprise a benzene base fused to three bicycle[2.

Picking on Carbonate: Kinetic Selectivity in the Encapsulation of Anions.

Supramolecular hosts bind to inorganic anions at a fast rate and select them in proportion with thermodynamic stability of the corresponding [anion⊂host] complexes, forming in a reversible manner. In this study, we describe the action of hexapodal capsule 1 and its remarkable ability to select anions based on a large span of rates by which they enter this host. The thermodynamic affinity of 1 toward eighteen anions extends over eight orders of magnitude (0 View Article and Find Full Text PDF

Molecular Recognition of Nerve Agents and Their Organophosphorus Surrogates: Toward Supramolecular Scavengers and Catalysts.

Nerve agents are tetrahedral organophosphorus compounds (OPs) that were developed in the last century to irreversibly inhibit acetylcholinesterase (AChE) and therefore impede neurological signaling in living organisms. Exposure to OPs leads to a rapid development of symptoms from excessive salivation, nasal congestion and chest pain to convulsion and asphyxiation which if left untreated may lead to death. These potent toxins are prepared on a large scale from inexpensive staring materials, making it feasible for terrorist groups or states to use them against military and civilians.

A Molecular Capsule with Revolving Doors Partitioning Its Inner Space.

Covalent capsule 1 was designed to include two molecular baskets linked with three mobile pyridines tucked into its inner space. On the basis of both theory (DFT) and experiments (NMR and X-ray crystallography), we found that the pyridine "doors" split the chamber (380 Å ) of 1 so that two equally sizeable compartments (190 Å ) became joined through a conformationally flexible aromatic barrier. The compartments of such unique host could be populated with CCl (88 Å ; PC=46 %), CBr (106 Å ; 56 %) or their combination CCl /CBr (PC=51 %), with thermodynamic stabilities ΔG° tracking the values of packing coefficients (PC).

The epididymis of the prepubertal swamp buffalo (Bubalus bubalis): histochemistry of phosphatases.

The distribution of phosphatases was examined in the epididymis of swamp buffaloes aged 1.5-2 years, where spermatogenic activity in the testis had reached the early primary spermatocyte stage. A granular distribution of acid phosphatase was present in the luminal region of the epithelium of the efferent ductules.

Influence of media and thermal shock on sperm capacitation.

To elucidate the influence of medium and thermal shock in inducing sperm capacitation, eight ejaculates were processed as follows. Each ejaculate was divided into three aliquots. To two of the aliquots, an equal volume of saline was added, while TEST-yolk was added to the remaining aliquot.

Pregnancy terminating effect of Jatropha curcas in rats.

The fertility regulatory effect of the fruit of Jatropha curcas was investigated by oral administration of different extracts to pregnant rats for varying periods of time. Foetal resorption was observed with methanol, petroleum ether and dichloromethane extracts indicating the abortifacient properties of the fruit. The results also suggest that the interruption of pregnancy occurred at an early stage after implantation.

TEST-yolk media and sperm quality.

Media prepared with egg yolk and two buffers, TES and Tris, called TEST-yolk have been shown to have beneficial effects on the survivability, fertilizing capacity and storage potential of human spermatozoa. Egg yolk lipoproteins are the critical compounds for the beneficial effects, with a synergistic effect due to the TES-Tris buffer component. TEST-yolk media have been used in the sperm penetration assay, the hemizona assay, sperm preparation for clinical in-vitro fertilization, artificial insemination with homologous spermatozoa, cryopreservation, sperm samples with a positive antisperm antibody test, and preparation for techniques requiring capacitated spermatozoa.

Ultrastructural localisation of alkaline phosphatase in the intertubular tissue of the testis in the domestic fowl.

Alkaline phosphatase activity in the intertubular tissue of the testes of the domestic fowl was examined using an ultracytochemical technique based on the lead capture method. In the interstitial tissue, the Leydig cells, transitional cells and the fibroblasts displayed enzyme activity on their cell membranes. Vacuoles located in the transitional cells were lined by reaction products of enzyme activity, whereas the vacuoles representing extracted lipid droplets and present mainly in the Leydig cells were free of enzyme activity.

Ultrastructural localisation of alkaline phosphatase in the testis of domestic fowl.

The ultrastructural distribution of alkaline phosphatase has been investigated in the testis of the domestic fowl. Enzyme activity was observed in the germinal epithelium and in the peritubular tissue. In both situations the activity was located in the plasma membranes.

Ultrastructural localization of phosphatases in the testes of the domestic fowl: acid phosphatase and thiamine pyrophosphatase.

ACPase and TPPase activity has been examined in the germinal epithelium of the testes in the domestic fowl. ACPase activity in spermatogonia and spermatocytes was confined to the Golgi complex. In spermatids ACPase activity was seen in the endoplasmic reticulum and nuclear envelope in the phase I and especially in the phase II (the elongating phase).

On the structure of the vascular body in the domestic fowl.

The microscopic structure of the vascular body has been described. Three cell types have been identified. The arrangement of blood and lymph vessels has been demonstrated by means of injection techniques, and these vessels have been investigated at an ultrastructural level.

Ultrastructural studies on the differentiation of spermatids in the domestic fowl.

Four phases of spermatid maturation are recognized on the basis of nuclear morphology. The formation of the acrosome, perforatorium and axial filament complex are described in relation to these phases. The functional significance of the microtubular systems in nuclear elongation and spermatid curvature are discussed.

Stages of spermatids in the domestic fowl: a light microscope study using Araldite sections.

Ten stages in spermatid maturation have been identified in the testis of the domestic fowl, using Araldite-embedded material. Identification of stages 1-3 was dependent on the position of the idiosome and the proacrosome granule. Stages 4-8 were identified by the shape of the acrosome, shape and length of nucleus, and the shape of the cell, The presence of the manchette and the mitochondrial sheath helped identify stages 9 and 10.