South Atlantic paleobathymetry since early Cretaceous

We present early Cretaceous to present paleobathymetric reconstructions and quantitative uncertainty estimates for the South Atlantic, offering a strong basis for studies of paleocirculation, paleoclimate and paleobiogeography. Circulation in an initially salty and anoxic ocean, restricted by the topography of the Falkland Plateau, Rio Grande Ridge and Walvis Rise, favoured deposition of thick evaporites in shallow water of the Brazilian-Angolan margins. This ceased as sea oor spreading propagated northwards, opening an equatorial gateway to shallow and intermediate circulation. This gateway, together with subsiding volcano-tectonic barriers would have played a key role in Late Cretaceous climate changes. Later deepening and widening of the South Atlantic, together with gateway opening at Drake Passage would lead, by mid-Miocene (∼15 Ma) to the establishment of modern-style thermohaline circulation

Effect of interactive ternary mixtures on dispersion characteristics of ipratropium bromide in dry powder inhaler formulations

The purpose of this investigation was to evaluate the effect of mixing order and the influence of adding fines on in vitro performance of ipratropium bromide (ITB) dry powder inhaler formulations. Coarse lactose (CL) in varying mass ratio with or without addition of micronized lactose (ML) and ITB in different mixing sequences was used to formulate ternary mixtures. A binary mixture composed of CL and ITP served as control. The in vitro deposition of ITB from these formulations was measured using an Andersen cascade impactor (aerosolization at 39 L/min) employing a HandiHaler as the delivery device. It was observed that mixing order has a significant effect (P<.05) on in vitro deposition of ITB. Formulations with preblending of CL and ITB produced similar deposition profiles as the control, regardless of the added ML. In contrast, formulations without preblending resulted in significantly higher fine particle dose (FPD) as compared with the control. In addition, an increased quantity of ML generally resulted in an increase in drug deposition. The results show that the effect of ML on dispersion of ITB is highly dependent upon the mixing order. The evaluation of atomic force measurement (AFM) to forecast drug detachment and predict the aerodynamic characteristics resulted in similar attraction forces for the different pairs lactose/lactose (42.66±25.01 nN) and lactose/ITB (46.77±17.04 nN)

Exploring the Potential of A Highly Compressible Microcrystalline Cellulose as Novel Tabletting Excipient in the Compaction of Extended-Release Coated Pellets Containing an Extremely Water-Soluble Model Drug

Compaction of controlled-release coated pellets into tablets is challenging because of the fusion of pellets and the rupturing of coated film. The difficulty in compaction intensifies with the use of extremely water-soluble drugs. Therefore, the present study was conducted to prepare and compact pellets containing pseudoephedrine hydrochloride as an extremely water-soluble model drug. The pellets were produced using an extrusion–spheronization technique. The drug-loaded pellets were coated to extend the drug release up to 12-h employing various polymers, and then they were compressed into tablets using microcrystalline cellulose Ceolus KG-801 as a novel tabletting excipient. The in vitro drug release studies of coated pellets and tablets were undertaken using the USP basket method in dissolution test apparatus I. The amount of drug released was analyzed at a wavelength of 215 nm. The combined coatings of hydroxypropyl methylcellulose and Kollicoat SR-30D yielded 12-h extended-release pellets with drug release independent of pH of dissolution medium following zero-order kinetics. The drug release from the tablets prepared using inert Celous KG-801 granules as tabletting excipient was found faster than that of coated pellets. However, a modification in drug release rate occurred with the incorporation of inert Ceolus KG-801 pellets. The drug dissolution profile from tablets containing 40% w/w each of coated pellets and inert granules along with 20% w/w inert pellets was found to be closely similar to that of coated pellets. Furthermore, the friability, tensile strength, and disintegration time of the tablets were within the USP specifications

A subset of calretinin-positive neurons are abnormal in Alzheimer's disease.

The distribution of the calcium-binding protein calretinin was investigated by immunohistochemistry in the hippocampus, the subicular areas, and the entorhinal cortex in patients with Alzheimer's disease and in control subjects. By double immunolabelling, the calretinin immunoreactivity was compared to the immunoreactivity for beta/A4 amyloid or for tau proteins. Calretinin-positive neurons were mainly observed in the molecular layer of the gyrus dentatus, the stratum radiatum of the Ammon's horn, and in layers II and III of the entorhinal cortex. The general pattern of calretinin immunoreactivity was conserved in Alzheimer's disease. Calretinin-positive neurons appeared normal in the hippocampus but had a reduced dendritic tree in the entorhinal cortex. Dystrophic calretinin immunoreactive fibres were often observed in the outer molecular layer of the gyrus dentatus and in the CA4 sector in Alzheimer's disease. Most neurons containing neurofibrillary tangles were not calretinin immunoreactive and most senile plaques were not associated with calretinin positive fibres. These results show that entorhinal calretinin-positive neurons are affected in Alzheimer's disease in spite of an absence of systematic association with neurofibrillary tangles and senile plaques.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe