The Neandertal lower right deciduous second molar from Trou de l'Abîme at Couvin, Belgium

A human lower right deciduous second molar was discovered in 1984 at the entrance of Trou de l'Abîme at Couvin (Belgium). In subsequent years the interpretation of this fossil remained difficult for various reasons: (1) the lack of taxonomically diagnostic elements which would support its attribution to either Homo (sapiens) neanderthalensis or H. s. sapiens; (2) the absence of any reliable chronostratigraphic interpretation of the sedimentary sequence of the site; (3) the contradiction between archaeological interpretations, which attributed the lithic industry to a transitional facies between the Middle and Early Upper Palaeolithic, and the radiocarbon date of 46,820 ± 3,290 BP obtained from animal bone remains associated with the tooth and the flint tools.Thanks to recent progress regarding these three aspects, the tooth from Trou de l'Abîme may now be studied in detail. Analyses of the morphology and enamel thickness of the fossil yielded diagnostic characters consistent with an attribution to Neandertals. Re-examination of the lithic industry of Couvin shows that it corresponds to the late Middle Palaeolithic rather than a transitional facies. Furthermore, a new analysis of the site stratigraphy indicates that the unit situated above the archaeological layer in which the tooth was found is probably a palaeosol of brown soil type. Comparison with the regional cave sequences as well as with the reference sequence from the Belgian loess belt tends to show that the most recent palaeosol of this type is dated between 42,000 and 40,000 BP. This is consistent with both a recently obtained AMS result at 44,500 BP and the published conventional date.     

Molecular Characteristics of Bovine Serum Albumin-Dextran Conjugates

Bovine serum albumin (BSA)-dextran conjugates were prepared by using the Maillard reaction; depending on the ratio of dextran to BSA used, about 0.5–1 mol of dextran could be bound to 1 mol of native BSA. SDS–PAGE patterns revealed that BSA and dextran had been covalently bonded. Structural analyses by fluorescence spectroscopy and circular dichroism indicated that the BSA surface in each conjugate was covered with dextran without any great disruption of the native conformation. The conjugates could be grouped into two fractions on the basis of the weight-average molecular mass measured: the main fraction at 1.95–2.35×10⁵ g/mol and a less-abundant fraction with aggregates greater than 1.50×10⁶ g/mol. High-performance size-exclusion chromatography in conjunction with multi-angle laser light scattering detection revealed that the BSA-dextran conjugates prepared by using the Maillard reaction had various molar masses and radii.     

Population features of Microphrys bicornutus Latreille, 1825 (Brachyura, Majidae) from Isla Margarita, Venezuela

The aim of this study is to characterize the population biology (sex ratio, size structure, relative growth of reproductive characters and realised fecundity) of the crab Microphrys bicornutusfrom Isla Margarita, Venezuela. Nearly 100 crabs were collected and fixed monthly during 1998. In the laboratory, crabs were sexed and measured: maximum carapace length, chelae length, chelae and abdomen width for females and first pleopod length for males. Additionally, 96 ovigerous females were collected to determine fecundity. The following measurements were taken for each female: body wet weight (BWW), body dry weight (BDW), egg wet weight (EWW), egg dry weight (EDW) and number of eggs (NE). The following determinations were made: relative fecundity (RF) = NE/BDW and reproductive output (RO) = (EDW/ BDW) × 100. Relative size at the onset of maturity (RSOM) was calculated as minimum ovigerous female/female's maximum size. The results indicate that the sex ratio is nearly 1:1 during the entire year. Ovigerous females and moulted males and females were observed throughout the year. Size frequency distribution and size at the onset of sexual maturity, estimated by relative growth of the sexual secondary characters and RSOM value, differed from those estimated in studies done in Jamaica and Buchuaco, Venezuela.     

乌江流域不同营养水平的梯级水库沉积物中磷形态特征

分析了乌江干流及支流不同营养水平的梯级水库(东风-贫营养、红岩-中营养、乌江渡-富营养)沉积物粒度的垂向分布,并以改进的连续提取法(SEDEX)调查了不同磷形态垂向分布特征。结果表明:3水库沉积物粒径均随深度的增加而减小,东风水库粒径最大,红岩水库其次,处于下游的乌江渡水库粒径最小;乌江渡、红岩和东风水库沉积物总磷(TP)的平均含量分别为2.07、1.22和1.11mg.g-1,总无机磷分别占到总磷53.8%、44.5%和81.9%,有机磷占TP的41.9%、55.5%和18.1%;3水库各形态磷所占比例不同,其中,乌江渡水库交换态磷所占比例相对较大,与其富营养化状态一致;乌江渡水库沉积物表层10cm,各形态磷含量随深度的增加呈下降趋势,红岩水库除交换态磷,其他各形态磷变化趋势不明显。东风水库各形态磷变化趋势不明显;河流梯级开发使下游水库颗粒物粒径变小,从而使下游水体中的磷更易吸附和释放,下游水库沉积物与水体交换也更强烈,除总磷外,交换态磷、自生磷和有机磷也可较好地反映水库富营养程度及演变。     

Product Quality Research Institute evaluation of cascade impactor profiles of pharmaceutical aerosols, part 1: Background for a statistical method

The purpose of this article is 2-fold: (1) to document in the public domain the considerations that led to the development of a regulatory statistical test for comparison of aerodynamic particle size distribution (APSD) of aerosolized drug formulations, which was proposed in a US Food and Drug Administration (FDA) draft guidance for industry; and (2) to explain the background and process for evaluation of that test through a working group involving scientists from the FDA, industry, academia, and the US Pharmacopeia, under the umbrella of the Product Quality Research Institute (PQRI). The article and the referenced additional statistical information posted on the PQRI Web site explain the reasoning and methods used in the development of the APSD test, which is one of the key tests required for demonstrating in vitro equivalence of orally inhaled and nasal aerosol drug products. The article also describes the process by which stakeholders with different perspectives have worked collaboratively to evaluate properties of the test by drawing on statistical models, historical and practical information, and scientific reasoning. Overall, this article provides background information to accompany the companion article's discussion of the study's methods and results. Published: January 19, 2007 Former address: Office of Generic Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration Rockville, MD     

Product Quality Research Institute evaluation of cascade impactor profiles of pharmaceutical aerosols: Part 2—Evaluation of a method for determining equivalence

The purpose of this article is to present the thought process, methods, and interim results of a PQRI Working Group, which was charged with evaluating the chi-square ratio test as a potential method for determining in vitro equivalence of aerodynamic particle size distribution (APSD) profiles obtained from cascade impactor measurements. Because this test was designed with the intention of being used as a tool in regulatory review of drug applications, the capability of the test to detect differences in APSD profiles correctly and consistently was evaluated in a systematic way across a designed space of possible profiles. To establish a “base line,” properties of the test in the simplest case of pairs of identical profiles were studied. Next, the test's performance was studied with pairs of profiles, where some difference was simulated in a systematic way on a single deposition site using realistic product profiles. The results obtained in these studies, which are presented in detail here, suggest that the chi-square ratio test in itself is not sufficient to determine equivalence of particle size distributions. This article, therefore, introduces the proposal to combine the chi-square ratio test with a test for impactor-sized mass based on Population Bioequivalence and describes methods for evaluating discrimination capabilities of the combined test. The approaches and results described in this article elucidate some of the capabilities and limitations of the original chi-square ratio test and provide rationale for development of additional tests capable of comparing APSD profiles of pharmaceutical aerosols. Published: January 19, 2007     

Reciprocal control of retinal rod cyclic GMP phosphodiesterase by its gamma subunit and transducin

The switching on of the cGMP phosphodiesterase (PDE) in retinal rod outer segments by activated transducin (T alpha-GTP) is a key step in visual excitation. The finding that trypsin activates PDE (alpha beta gamma) by degrading its gamma subunit and the reversal of this activation by gamma led to the proposal that T alpha-GTP activates PDE by relieving an inhibitory constraint imposed by gamma (Hurley and Stryer: J. Biol. Chem. 257:11094-11099, 1982). We report here studies showing that the addition of gamma subunit also reverses the activation of PDE by T alpha-GTP-gamma S. A procedure for preparing gamma in high yield (50-80%) is presented. Analyses of SDS polyacrylamide gel slices confirmed that inhibitory activity resides in the gamma subunit. Nanomolar gamma blocks the activation of PDE by micromolar T alpha-GTP gamma S. The degree of activation of PDE depends reciprocally on the concentrations of gamma and T alpha-GTP gamma S. gamma remains bound to the disk membrane during the activation of PDE by transducin. The binding of gamma to the alpha beta subunits of native PDE is very tight; the dissociation constant is less than 10 pM, indicating that fewer than 1 in 1,700 PDE molecules in rod outer segments are activated in the absence of T alpha-GTP.     

The Abbreviated Impactor Measurement (AIM) Concept: Part II—Influence of Evaporation of a Volatile Component—Evaluation with a “Droplet-Producing” Pressurized Metered Dose Inhaler (pMDI)-Based Formulation Containing Ethanol as Cosolvent

The abbreviated impactor measurement (AIM) concept is a potential solution to the labor-intensive full-resolution cascade impactor (CI) methodology for inhaler aerosol aerodynamic particle size measurement. In this validation study, the effect of increasing the internal dead volume on determined mass fractions relating to aerodynamic particle size was explored with two abbreviated impactors both based on the Andersen nonviable cascade impactor (ACI) operating principle (Copley fast screening Andersen impactor [C-FSA] and Trudell fast screening Andersen impactor [T-FSA]). A pressurized metered dose inhaler-delivered aerosol producing liquid ethanol droplets after propellant evaporation was chosen to characterize these systems. Measures of extrafine, fine, and coarse particle mass fractions from the abbreviated systems were compared with corresponding data obtained by a full-resolution ACI. The use of liquid ethanol-sensitive filter paper provided insight by rendering locations visible where partly evaporated droplets were still present when the “droplet-producing” aerosol was sampled. Extrafine particle fractions based on impactor-sized mass were near equivalent in the range 48.6% to 54%, comparing either abbreviated system with the benchmark ACI-measured data. The fine particle fraction of the impactor-sized mass determined by the T-FSA (94.4 ± 1.7%) was greater than using the C-FSA (90.5 ± 1.4%) and almost identical with the ACI-measured value (95.3 ± 0.4%). The improved agreement between T-FSA and ACI is likely the result of increasing the dead space between the entry to the induction port and the uppermost impaction stage, compared with that for the C-FSA. This dead space is needed to provide comparable conditions for ethanol evaporation in the uppermost parts of these impactors.     

Inhibitory probes of mitochondrial ATPase and the action of DDT

Chemical inhibitors were used as probes of mitochondrial ATPase to determine the site of action of DDT on oligomycin-sensitive mitochondrial ATPase (OS-ATPase) using whole mitochondria isolated from red coxal muscle of the American cockroach. Several plotting procedures were employed to delineate the form of inhibition. Relative potency and joint action were used to detect similar action, synergism, and antagonism between DDT and the inhibitory probes DCCD, Nbf-CI, and oligomycin. DDT demonstrated not (strictly) competitive kinetics and may be acting as an uncompetitive inhibitor. DDT and DCCD produced similar additive action. At limiting concentrations of DCCD, inhibition was reduced in the presence of DDT. Effects shown by oligomycin were not altered by DDT. DDT enhanced the effects of Nbf-CI. These interactions, together with the demonstration of not (strictly) competitive kinetics, indicate that DDT may be acting on the membrane sector as an allosteric modifier.     

Foraging habitat determines predator–prey size relationships in marine fishes

Predator–prey size (PPS) relationships are determined by predator behaviour, with the likelihood of prey being eaten dependent on their size relative to that of the consumer. Published PPS relationships for 30 pelagic or benthic marine fish species were analysed using quantile regression to determine how median, lower and upper prey sizes varied with predator size and habitat. Habitat effects on predator foraging activity/mode, morphology, growth and natural mortality are quantified and the effects on PPS relationships explored. Pelagic species are more active, more likely to move by caudal fin propulsion and grow more rapidly but have higher mortality rates than benthic species, where the need for greater manoeuvrability when foraging in more physically complex habitats favours ambush predators using pectoral fin propulsion. Prey size increased with predator size in most species, but pelagic species ate relatively smaller prey than benthic predators. As pelagic predators grew, lower prey size limits changed little, and prey size range increased but median relative prey size declined, whereas the lower limit increased and median relative prey size was constant or increased in benthic species.