Fossils, molecules and embryos: new perspectives on the Cambrian explosion

The Cambrian explosion is named for the geologically sudden appearance of numerous metazoan body plans (many of living phyla) between about 530 and 520 million years ago, only 1.7% of the duration of the fossil record of animals. Earlier indications of metazoans are found in the Neoproterozic; minute trails suggesting bilaterian activity date from about 600 million years ago. Larger and more elaborate fossil burrows appear near 543 million years ago, the beginning of the Cambrian Period. Evidence of metazoan activity in both trace and body fossils then increased during the 13 million years leading to the explosion. All living phyla may have originated by the end of the explosion. Molecular divergences among lineages leading to phyla record speciation events that have been earlier than the origins of the new body plans, which can arise many tens of millions of years after an initial branching. Various attempts to date those branchings by using molecular clocks have disagreed widely. While the timing of the evolution of the developmental systems of living metazoan body plans is still uncertain, the distribution of Hox and other developmental control genes among metazoans indicates that an extensive patterning system was in place prior to the Cambrian. However, it is likely that much genomic repatterning occurred during the Early Cambrian, involving both key control genes and regulators within their downstream cascades, as novel body plans evolved.     

The founding of the Psychological Laboratory, University College London: "Dear Galton…Yours truly, J Sully."

The events leading up to the founding of the Psychological Laboratory at University College London are examined in the light of correspondence from James Sully to Francis Galton. The correspondence reveals the dependence of Sully on Galton for detailed advice at every stage of the process, possible reasons for which are discussed. It also provides sufficient clues to enable identification of a hitherto anonymous donor. Although Galton may have inspired and advised on the initial setting up of the laboratory, his influence on its work did not become apparent until after his death. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Orientated crystallization in drawn thermoplastic polyimide modified by carbon nanofibers

The solid state crystallization in drawn thermoplastic polyimide films is studied as a function of draw ratio (DR) under the effect of vapor grown carbon fiber nanoinclusions. The nucleating effect of the nanoinclusions coupled with the orientation effect of drawing generates a unique orientated layered lamellar structure, characteristic of smectic‐like mesophase. The degree of draw induced orientated crystallization increases with the content of nanoinclusions and with the DR, and is reflected in the mechanical behavior of the film. Generally, the Young's modulus and the yield point of the drawn crystalline films in the drawing direction are significantly higher compared with the noncrystalline counterparts. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

Palladium‐nanoparticle intercalated vermiculite for selective hydrogenation of α,β‐unsaturated aldehydes

Palladium nanoparticles were generated in the interlamellar region of swelling 2:1 type vermiculite clay using an adsorption excess isotherm. An adsorption excess isotherm was constructed for vermiculite after exchanging the exchangeable Na⁺ ions in the interlamellar region using a binary liquid mixture (ethanol:toluene). Based on adsorption excess isotherm, 1% w/w palladium was intercalated into the interlamellar space of vermiculite. The Pd‐intercalated vermiculite was characterized by X‐ray diffraction, transmission electron microscopy and atomic absorption spectroscopy. The 1% w/w Pd‐intercalated vermiculite was tested for its catalytic activity towards selective hydrogenation reactions involving some α,β‐unsaturated carbonyl compounds using a pulse reactor and its catalytic activity was compared with commercial 1% Pd/C. The intercalated catalyst was found to be very selective towards the desired product of unsaturated alcohols. Copyright © 2007 Society of Chemical Industry     

Actively stabilised diode pumped Tm:YAlO laser

An actively stabilised, continuous-wave, 1.94 /spl mu/m Tm:YAlO laser is presented. Optoelectronic negative feedback stabilisation is utilised to prevent relaxation-oscillation-driven spiking. The amplitude stability of the laser is found to be very robust against cavity perturbation and parasitic radiation back-reflection, making it attractive for practical applications.     

Subunit of glycosylation-inhibiting factor is an abundant protein that binds to certain glycoproteins and sugars

The adherence of Staphylococcus aureus to biomaterials used in orthopaedic surgery (polymethylmethacrylate, fresh bone, steel and titanium alloys) and to glass was studied in vitro at 1, 2, 6, 24 and 48 h of incubation. Nonslime-producing strains (72, 80 and 510) and slime-producing variants of these strains were used. An automated and fast method of ATP-bioluminiscence was applied to determine bacterial viability. The lowest adherence corresponded to polymethylmethacrylate and bone, and the highest to metals. Significant adherence was detected in all cases after 6 h and was strain dependent, being lowest for strain 72. In most cases, adherence of nonslime-producing variants was not significant compared with controls, and slime-producing were more adherent than nonslime-producing variants. These differences were maximal at 6 h or 48 h, depending on the strain and the material. The findings suggest that the appearance of slime-producing cells within a given nonslime-producing bacterial population may jeopardise postoperative immune systems and antibiotic efficacy as a consequence of biofilm formation on implants and prostheses.     

Ethanol enhancement of Pavlovian conditioning.

60 New Zealand albino rabbits were tested for Pavlovian conditioning and extinction of eye-blink (EB) and heart-rate (HR) responses following water or various doses of oral ethanol (375–2,500 mg/kg). The highest dose suppressed both EB and HR conditioning during training, whereas the lowest dose enhanced HR responses during training and increased EB responses during later extinction in a symmetrically state-dependent manner. An intermediate dose (750 mg/kg) administered during training enhanced HR responses and suppressed EB responses but increased EB responses during later extinction following either ethanol or water. Ethanol treatments also suppressed unconditioned responses (UCRs) to shock and increased locomotor activity; however, these effects differed qualitatively from those that ocurred during Pavlovian training and extinction. Results suggest that very low doses of ethanol can enhance the ability of stimuli to elicit Pavlovian conditioned reflexes and impair the ability to adaptively modify these reflexes when stimulus contingencies later change. (55 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relation between the time to achieve the lower limit of the APTT therapeutic range and recurrent venous thromboembolism during heparin treatment for deep vein thrombosis

BACKGROUND: Randomized trials have demonstrated the importance of achieving adequate heparinization early in the course of therapy. Recently, some authors reported a pooled analysis of selected studies in the literature that suggested that there is no convincing evidence that the risk of recurrent venous thromboembolism is critically dependent on achieving a therapeutic activated partial thromboplastin time result at 24 to 48 hours. METHODS: We provide the analyses of patient groups entered into our series of 3 consecutive double-blind randomized trials evaluating initial heparin therapy for proximal deep venous thrombosis. RESULTS: Logistic regression analysis of the patient groups receiving the less intense initial intravenous heparin dose of 30,000 U/24 h demonstrated that subtherapy for 24 hours predicted the onset of venous thromboembolic events. Failure to achieve a therapeutic activated partial thromboplastin time by 24 hours was associated with a 23.3% frequency of venous thromboembolism vs 4% to 6% for those whose activated partial thromboplastin time exceeded the therapeutic threshold by 24 hours (P=.02). Time-to-event analysis shows the increased frequency of recurrent venous thromboembolic events during the period of study in patients who were subtherapeutic for 24 hours compared with those who were therapeutic (P=.001). CONCLUSIONS: Our findings reaffirm the clinical importance of rapidly achieving therapeutic levels of heparin. Patients who failed to achieve the therapeutic threshold by 24 hours were at an increased risk of subsequent recurrent venous thromboembolism. These findings are independently supported by the results of a randomized trial comparing different intensities of initial heparin treatment by continuous infusion.     

Linear and nonlinear effects of aging on categorizing and naming faces.

Ss aged 54–84 yrs performed 5 separate tasks involving various aspects of face processing: (1) structural decisions, (2) familiarity decisions, (3) semantic decisions, (4) 1st-name decisions, and (5) name retrieval. For the categorization tasks (1–4), the mean reaction times (RTs) for the older Ss (over 65) were plotted against the corresponding means for the younger Ss (under 65). This produced a linear function (slope >1, intercept