Chemical evolution: The first stages

The available data on the syntheses of critically important precursor molecules for chemical evolution are reviewed and problems of rates of production versus rates of destruction in the primitive ocean are discussed. It is concluded that many global chemical syntheses would have been improbable in the Earth's oceans and that more attention should be paid to specific environments which would have favored such syntheses. The recent discovery of an accelerating effect of formaldehyde on the oligomerization of HCN as well as the eutectic-concentration mechanism are discussed in relation to a new scenario for chemical evolution on the primitive Earth.     

Prenatal detection of trisomy 9 mosaicism

Chromosomal mosaicism in amniotic fluid cells poses a serious dilemma in prenatal diagnosis since the observation may represent: (1) pseudomosaicism—an inconsequential tissue culture artefact; or (2) true mosaicism—occurring in approximately 0.0 per cent of amniocenteses with a significant impact on pregnancy outcome. Mosaicism for trisomy 9 was observed in an amniotic fluid specimen obtained for advanced maternal age with two cell lines [46,XX (46 per cent)/47,XX, + 9 (54 per cent)] present in each of four culture flasks. Since more than 75 per cent of newborns with trisomy 9 mosaicism have complex cardiac malformations, a fetal echocardiogram was obtained at 20 weeks' gestation and interpreted as normal. A fetal blood sample (22 weeks' gestation) disclosed only a single trisomy 9 cell among the 100 metaphases analysed. However, a second fetal echocardiogram performed at the time of blood sampling suggested a non-specific cardiac anomaly. Fetal autopsy following elective pregnancy termination revealed several malformations including severe micrognathia, persistence of the left superior vena cava, and skeletal anomalies. Cytogenetic studies of cell cultures derived from several fetal tissues demonstrated trisomy 9 ranging from 12 to 24 per cent.     

Water to atmosphere fluxes of 131I in relation with alkyl-iodide compounds from the Seine Estuary (France)

This study presents an original work on measurements of stable and radioactive iodinated species in the Seine estuary (France), with estimates fluxes of volatile gaseous species from water to the atmosphere. Various iodinated compounds were identified in water and air in particular 131I in water, what is unusual. Concentrations and behaviour of iodinated elements in the Seine estuary seem similar to what has been observed in other European estuaries. MeI (Methyl Iodide) and Total Volatile Iodine (TVI) fluxes from water to air vary between 392 and 13949 pmol m(-2) d(-1) and between 1279 and 16484 pmol m(-2) d(-1), respectively. Water to air flux of TVI for the Seine river was estimated in the range 4-46 kg y(-1). Measurements of (131)I in water varying between 0.4 and 11.9 Bq m(-3). Fluxes of (131)I from water to atmosphere are in the range 2.4 x 10(5)-1.3 x 10(7)Bq y(-1), close to an annual discharge of (131)I by a nuclear reactor.     

Effectiveness of high back belt positioning booster seats in side impacts

OBJECTIVE: The objective of this study is to evaluate the potential of high back booster seats to provide effective protection to children in side impacts. METHOD: This article presents a series of side impact sled tests at a velocity change of 30.5 km/h and a peak deceleration of 15.2 g, using the Hybrid III 6-year-old dummy in two styles of commonly used high-back booster seats: a conventional polystyrene booster seat and a convertible child restraint/booster seat. A series of tests were also performed using alternative anchorage systems in combination with the boosters. Simulated side impact tests were conducted at 90 degrees and 45 degrees. RESULTS: The booster seats tested were found to be too short for the 6-year-old dummy and head contact with the side door occurred in all 90 degree tests, resulting in high HIC values. The greatest potential for achieving effective protection in side impact in this test series was observed when the convertible child restraint/booster was used in combination with a rigid anchorage system. Using this system, the body of the dummy was kept farther away from the door which resulted in a softer head impact with the side door. CONCLUSIONS: Results from this work indicate that current booster seats offer poor torso containment and no head protection for children within the recommended age range. They also showed that the level of protection provided by belt positioning booster seats can be improved through the use of rigid anchorage systems. However, for this potential to be fully realized, belt positioning booster seats must offer better containment of the occupant during the impact.     

Acute impairing effects of morphine related to driving: A systematic review of experimental studies to define blood morphine concentrations related to impairment in opioid-naïve subjects

Objective: The objective of this study was to look for dose– and concentration–effect relationships in experimental studies on single-dose administration of morphine on traffic-relevant behavioral tests by a systematic literature review and possibly to see whether a dose/concentration could be defined below which few or no tests would be affected.

Methods: Searches for corresponding literature were conducted using MEDLINE, EMBASE, and PsycINFO, throughout March of 2016. The search strategy consisted of words colligated to cognitive and psychomotor functions of relevance to driving, in relation to morphine administration. The tests were arranged in main groups, and tests showing impairment were categorized by doses as well as calculated plasma concentrations.

Results: Fifteen studies were included in the review. Impairment after the administration of a single intravenously dose of morphine was found in some of the tests on reaction time, attention, and visual functions. No impairment was observed in tests on psychomotor skills and en-/decoding. Tests on reaction time appeared to be less sensitive to the morphine administration, whereas tests on visual functions and attention appeared to be the most sensitive to the morphine administration. Single-dose administration of morphine with dosages up to 5 mg appeared to cause very few effects on traffic-relevant performance tasks. At higher dosages, impairment was found on various tasks but with no clear dose–effect relationship. Plasma morphine concentrations less than 50 nmol/L are most probably accompanied by few effects on traffic-relevant performance tasks.

Conclusions: A plasma morphine concentration of 50 nmol/L (approximately 14.3 ng/mL) could represent an upper level, under which there is little accompanying road traffic risk. A single dose of 5 mg morphine IV and analgetic equivalence doses of fentanyl, hydromorphone, oxycodone, and oxymorphone are presented with the suggestion that few traffic-relevant effects will appear after such doses.     

Screening of Ready-to-Eat Meat Products for Hepatitis E Virus in Switzerland

Seroprevalence data for pig herds suggested that there must be a relevant reservoir for hepatitis E virus (HEV) in Switzerland. To know more about the viral presence in ready-to-eat meat products, we screened pork liver sausages and raw meat sausages from the Swiss retail market for the presence of HEV. Testing was performed with a detection method where the virus extraction step was optimized. As for the performance of the improved method, the mean recovery rate for the mengovirus process control was 24.4%, whereas for HEV-inoculated sample matrices between 10.4 and 100% were achieved. The limit of detection was about 1.56 × 10³ and 1.56 × 10² genome copies per gram for liver sausages and raw meat sausages, respectively. In the screening programme, HEV-RNA was detected in 10 of total 90 (11.1%) meat products, 7 of 37 (18.9%) liver sausages, and 3 of 53 (5.7%) raw meat sausages. Virus loads of up to 5.54 log₁₀ HEV genome copies per gram were measured. All sequences retrieved from positive samples belonged to HEV genotype 3. The significance of the presented work was a current overview of the HEV prevalence in ready-to-eat meat products on the Swiss retail marked and an improvement of the extraction efficiency of the HEV detection method.     

Carbohydrate and calling: Depletion of muscle glycogen and the chorusing dynamics of the neotropical treefrog Hyla microcephala

Chorusing males of the neotropical treefrog Hyla microcephala call in distinct bouts punctuated by periods of silence, a pattern known as unison bout singing. Schwartz (1991) previously tested and refuted the hypotheses that males periodically stop calling either because of a female preference for males that call cyclically, or because high ambient noise levels inhibit vocal activity. Males of H. microcephala are vocally responsive to the calls of other males, and during calling bouts their rate of note production can exceed 10,000 per hour. In natural choruses females preferentially pair with males that call at the higher rates. Because females can pair with males over many hours, males may stop calling periodically to save energy so they can continue to call for the entire period that females are available. We directly tested this energy conservation hypothesis by collecting samples of males early in the evening just after chorusing commenced and later when chorusing had ended for the night. Trunk muscles (internal and external oblique), which are responsible for the airflow associated with note production, were dissected, frozen, and their glycogen content measured. Data on calling behavior were obtained for late-evening samples. Individual calling behavior was not correlated with a males final glycogen level. In addition, many males ended their calling before glycogen reserves were exhausted, indicating that factors other than energy can determine when males finally stop chorusing, However, the biochemical assays supported the energy conservation hypothesis. Unless chorusing was punctuated by pauses, most males would have been unable to sustain high rates of calling for an entire evening without exhausting glycogen reserves in their trunk muscles. Because the time females pair with males is probably unpredictable to males, the ability to call for long periods may improve a males chances of mating.     

Multiple paternity in wild populations of the garter snake,Thamnophis sirtalis

Summary Many adaptations have arisen in response to spern competition. In garter snakes, males produce copulatory plugs that are thought to prevent such competition. We tested this assumption using paternity exclusion techniques with electrophoretic data from 32 litters of snakes collected from two populations. Multiple paternity was confirmed in 50% of the litters examined (13/22 Michigan litters; 3/10 Wisconsin litters), and we estimate that as many as 72% of the litters may have been multiply sired. The presence of multiple paternity was also confirmed using the technique of genotypic regression. Mean relatedness in litters with evidence of multiple paternity was 0.390±0.053; in litters lacking such evidence mean relatedness was 0.498±0.022. Thus our data reveal a high incidence of multiple paternity in these snakes and suggest that their adaptations to prevent sperm competition are surprisingly ineffective.