Localized CO2 laser damage repair of fused silica optics

A technique has been developed for the localized treatment of laser damage sites in fused silica optics by CO2 laser melt-flow smoothing, by using a 50 to 125 microm diameter beam in a regime that avoids mass removal by ablation. A detailed calibration of the laser irradiance for the threshold ablation of craters was carried out for a range of beam diameters and pulses in the 20 micros to 200 ms range. The results agree with a thermal model that also provides estimates of the melt depth for the different irradiation conditions. Smoothing trials for glass melting at irradiance values just below the ablation threshold irradiance were conducted to determine the optimum conditions and limits for the smoothing process. The technique has been found to remove damage pits up to a depth of 0.5 microm, while the small melt depth associated with localized treatment limits the smoothing to a <or=5 microm lateral size.

Identification of components of male-produced pheromone of coffee white stemborer, Xylotrechus quadripes

The coffee white stem borer, Xylotrechus quadripes Chevrolat (Coleoptera: Cerambycidae), is the foremost pest of arabica coffee in India, Sri Lanka, China, Vietnam, and Thailand. Previous work showed that female beetles were attracted to traps baited with male beetles. Analyses of volatiles from male X. quadripes of Indian origin by gas chromatography (GC) linked to electroantennographic (EAG) recording from a female beetle antenna showed three male-specific components comprising more than 90% of the volatiles, two of which elicited EAG responses. The major EAG-active component was produced at up to 2 microg hr(-1) insect(-1) and was identified as (S)-2-hydroxy-3-decanone (I) by comparison of GC data, and mass (MS), infrared, and nuclear magnetic resonance (NMR) spectra with those of synthetic standards. The second component was identified as 3-hydroxy-2-decanone (II) produced in part by isomerization of I under the conditions of the GC analysis, although the NMR spectrum suggested it is naturally produced at up to 7% of I. The minor component that elicited an EAG response, present at 7% of the amount of I, was identified as (S,S)-2,3-dihydroxyoctane (III) from GC and MS data. 2-Hydroxy-3-octanone (0.2-0.5% of I), 2,3-decanedione (2% of I), 2-phenylethanol (3% of I), and octanoic acid (4% of I) were also identified in volatiles from male beetles. A general, stereospecific synthetic route to the enantiomers of 2-hydroxy-3-alkanones from the enantiomers of ethyl lactate was developed. The enantiomers of III were synthesized from (E)-2-octene by Sharpless asymmetric dihydroxylation. (S)-(I) was attractive to male X. quadripes in laboratory bioassays, but addition of (S,RS)-(III) at 10% of I reduced attractiveness. In field trials carried out in India with sticky, cross-vane traps, (S)- and (RS)-(I) attracted male X. quadripes and addition of (S,S)-(III) at 10% of I reduced attractiveness. Significant numbers of female Demonax balyi Pascoe (Coleoptera: Cerambycidae) were sometimes caught in traps baited with (S)-(I) alone.

The effects of host physiology on the attraction of tsetse (Diptera: Glossinidae) and Stomoxys (Diptera: Muscidae) to cattle

In Zimbabwe, studies were made of the numbers of tsetse (Glossina spp.) and stable flies (Stomoxys spp.) attracted to cattle of different nutritional status, age and sex. Host odours were analysed to determine the physiological basis of these differences and improved methods are described for measuring rates of production of kairomones. Seasonal fluctuations in host weight, related to changes in pasture quality, had no significant effect on attraction of tsetse or Stomoxys. However, both attraction to different individuals and carbon dioxide production by these individuals were strongly correlated with weight, suggesting a possible link. Attraction to the odour from different types of cattle decreased in the order ox>cow>heifer>calf, and oxen were twice as attractive as calves of less than 12 months old. Lactation did not alter the relative attractiveness of cows. Calves less than six months old produced lower levels of carbon dioxide, acetone, octenol and phenols than oxen, but for older calves and cows, levels of production of known kairomones and repellents were similar to those of an ox. Carbon dioxide produced by cattle varied according to time of day and the animal's weight; cattle weighing 500 kg produced carbon dioxide at a mean rate of 2.0 l min(-1) in the morning and 2.8 l min(-1) in the afternoon compared to respective rates of 1.1 and 1.9 l min(-1) for cattle weighing 250 kg. Artificially adjusting the doses of carbon dioxide produced by individual cattle to make them equivalent did not remove significant differences in attractiveness for tsetse but did for Stomoxys. Increasing the dose of carbon dioxide from 1 to 4 l min(-1) in a synthetic blend of identified kairomones simulating those produced by a single ox, increased attractiveness to tsetse but not to the level of an ox. The results suggest that the main sources of differences in the attractiveness of individual cattle are likely to be variation in the production of carbon dioxide and, for tsetse, other unidentified kairomone(s). The biological and practical implications of these findings are discussed.

The care and nurture of undulator data sets

Undulator radiation is the X-ray source of choice for modern macromolecular crystallography beamlines. Here, the basic properties of undulator sources are described and it is indicated why they make such good X-ray sources for macromolecular crystallography. Collection of excellent data from these beamlines is not always straightforward; therefore, a number of rules are postulated for undulator data collection and guidelines are offered which will help to ensure a satisfactory experiment.

The attitudes of two groups of South African women towards mode of delivery

OBJECTIVE

To determine whether 2 specific groups of women prefer vaginal or abdominal delivery.

METHODS

Forty-six black and 54 colored (of mixed race, the predominant population group) primigravidas and 59 black and 62 colored multigravidas were interviewed between April 2003 and February 2004 at Tygerberg Hospital, Tygerberg, South Africa.

RESULTS

Among primigravidas, 89% of black women and 83% of colored women preferred vaginal delivery. Among the multigravidas, 86% of black women and 79% of colored women preferred vaginal delivery. Most women believed that they would recover more quickly (65%) and with less pain (32%) after vaginal delivery. Forty-one percent of all women viewed episiotomy as the greatest disadvantage of vaginal delivery, while 43% were unaware of any advantage to cesarean delivery.

CONCLUSION

Most colored and black women preferred vaginal over cesarean delivery. A challenge to healthcare personnel is to educate women about both routes.

Responses of Teretrius nigrescens toward the dust and frass of its prey, Prostephanus truncatus

Teretrius nigrescens is considered to be a specialized predator of Prostephanus truncatus, a serious pest of stored maize and dried cassava roots. Using a bait-bag behavioral bioassay, this investigation found T nigrescens to be strongly arrested by dust and frass produced by P. truncatus on maize, whereas responses to maize flour were weak. Attempts to increase the arrestiveness of flour by altering its physical properties (coarseness or particle size range) were unsuccessful. The arrestive property of dust/frass did not degrade with long-term storage nor did it volatilize or degrade with oven baking up to 150 degrees C. However, extraction with methanol and reapplication was successful in transferring the arrestive property from the dust/frass onto maize flour. The prey dust/frass also induced more oviposition than did maize flour, as judged by production of F1 offspring. The results provide strong evidence for the existence of a high boiling point compound(s) in P. truncatus dust/frass that acts as a contact kairomone for T nigrescens. This, or another compound(s) also seems to act as an oviposition stimulant for female T. nigrescens.

Investigation of Long-Range Female Sex Pheromone of the European Tarnished Plant Bug, Lygus rugulipennis: Chemical, Electrophysiological, and Field Studies

The European tarnished plant bug, Lygus rugulipennis, is an important pest of agricultural and horticultural crops throughout Europe. Adult male L. rugulipennis were previously shown to be attracted to traps baited with live virgin females, which suggests the females produce a sex pheromone. Volatiles produced by virgin female L. rugulipennis were shown to contain three components, hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal which elicited electroantennographic (EAG) responses from males in analyses by linked gas chromatography-electroantennography (GC-EAG). They were produced in 1.5:1:0.08 ratio, respectively, by single females. Collections from 1, 2, or 4 virgin females showed the proportions of hexyl butyrate and (E)-4-oxo-2-hexenal to increase relative to that of (E)-2-hexenyl butyrate with increasing number of females. Although these compounds were found in body extracts of both male and female L. rugulipennis, they were not detected in volatiles released by virgin males. EAG dose-response studies showed that both males and females responded to these chemicals with minimal differences in sensitivity between the sexes or to the three components, except that males were more responsive than females to (E)-4-oxo-2-hexenal at the two highest doses tested. Release rates of the compounds from rubber septa, polyethylene vials, and polyethylene sachets were measured under laboratory conditions. Four field tests were carried out using sticky traps baited with all possible binary and tertiary combinations of the three chemicals using different combinations of dispensing systems. Catches of male L. rugulipennis in baited traps were similar to those in unbaited traps. Significantly fewer females were caught on traps baited with blends containing hexyl butyrate than on traps without hexyl butyrate or unbaited traps in one test and overall. The roles of the three compounds and possible reasons for their failure to attract males are discussed.

The profile and complications of women with placental abruption and intrauterine death

The aim of this study was to evaluate the profile and outcome of patients with placental abruption and intrauterine death. It was a retrospective study over 2 years from 1 January 1999 to 31 December 2000. All women (n = 96) presenting with placental abruption and intrauterine death at a tertiary referral center were identified from the records of weekly perinatal mortality meetings. Data were reviewed by a single researcher. Hypertensive disorders were diagnosed in 75 per cent (n = 72) women, most often at admission once intrauterine death had already occurred. Thirty-nine per cent had a previous history of hypertensive disease during pregnancy, placental abruption, intrauterine death, or preterm delivery. Twenty-two per cent of patients (n = 21) were unbooked. Major maternal complications occurred in 53 per cent of women. There were no maternal deaths. In conclusion, previous obstetric history and hypertensive disorders are important factors in women with placental abruption causing intrauterine death. Severe complications are common but careful management in a tertiary center can reduce their impact.

Phenotypic plasticity of Rhyzopertha dominica pheromone signaling: the effects of different hosts and presence of conspecific females on male produced aggregation pheromone

Male Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) release an aggregation pheromone consisting of a blend of two components, dominicalure 1 (D1) and Dominicalure 2 (D2). Pheromone from single insects, in different contexts, was collected and measured to determine if this signal is phenotypically plastic. Release rates were lowered when males were moved from maize grains to groundnut kernels or when moved from solitary occupation of maize grain to grain occupied by seven females. The pheromone release was increased again once these moves were reversed. The release of D1 was more affected than D2: thus, on groundnuts or in the presence of females, less pheromone was released and the proportion of D1 in the blend was lowered. Possible reasons for the modifications of the signal are discussed.

Minor components in the sex pheromone of legume podborer: Maruca vitrata development of an attractive blend

The legume podborer, Maruca vitrata (syn. M. testulalis) (F.) (Lepidoptera: Pyralidae) is a pantropical pest of legume crops. Sex pheromone was collected by gland extraction or trapping of volatiles from virgin female moths originating in India, West Africa, or Taiwan. Analysis by GC-EAG and GC-MS confirmed previously published findings that (E,E)-10,12-hexadecadienal is the most abundant EAG-active component with 2-5% of (E,E)-10,12-hexadecadienol also present. At least one other EAG response was detected at retention times typical of monounsaturated hexadecenals or tetradecenyl acetates, but neither could be detected by GC-MS. Laboratory wind-tunnel bioassays and a field bioassay of blends of (E,E)-10,12-hexadecadienal with (E,E )-10,12-hexadecadienol and a range of monounsaturated hexadecenal and tetradecenyl acetate isomers indicated greatest attraction of males was to those including (E,E)-10,12-hexadecadienol and (E)-10-hexadecenal as minor components. In subsequent trapping experiments in cowpea fields in Benin, traps baited with a three-component blend of (E,E)-10,12-hexadecadienal and these two minor components in a 100:5:5 ratio caught significantly more males than traps baited with the major component alone, either two-component blend, or virgin female moths. Further blend optimization experiments did not produce a more attractive blend. No significant differences in catches were found between traps baited with polyethylene vials or rubber septa, or between lures containing 0.01 and 0.1 mg of synthetic pheromone. Significant numbers of female M. vitrata moths, up to 50% of total catches, were trapped with synthetic blends but not with virgin females. At present there is no clear explanation for this almost unprecedented finding, but the phenomenon may improve the predictive power of traps for population monitoring.

Primipaternity and duration of exposure to sperm antigens as risk factors for pre-eclampsia

OBJECTIVE

To establish whether primipaternity and duration of unprotected sexual cohabitation is associated with an increased risk of pre-eclampsia.

METHOD

At a tertiary referral center, the study had a case and control group of 60 multigravid women each, as well as a case and control group of 50 primigravid women each. Information was compiled by means of a confidential questionnaire.

RESULT

After multiple logistic regression analysis using age, smoking, hypertension in previous pregnancies, change of paternity and duration of unprotected sexual cohabitation as predictors, the regression coefficients for change of paternity and sexual cohabitation of longer than 6 months in multigravid women were -0.4 (P = 0.15) and -1.4 (P = 0.03), respectively.

CONCLUSION

Multigravid women with a period of unprotected sexual cohabitation of longer than 6 months had a decreased risk of pre-eclampsia. Primipaternity was not a significant risk factor for pre-eclampsia.

Intermale variation in aggregation pheromone release in Prostephanus truncatus

Intermale variation in pheromone signaling has been confirmed and quantified by measurements of pheromone produced by single adult male Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae). Males varied in both the amounts of the two components of their aggregation pheromone and the ratio of one component to the other. The mean rates of production of the pheromone components T1 and T2 were 1.9 and 0.5 microg/day, respectively. There were repeatable differences among males in the amounts of T2 produced and the proportion of T1 in the pheromone blend over two weeks. Of the 15 males studied, one released a large burst of pheromone in a short period, while the remainder, if they did release, did so over an extended period. This suggested that there may be two alternative release strategies and the significance of this is discussed.

Identification of methyl salicylate as the principal volatile component in the methanol extract of root bark of Securidaca longepedunculata Fers

Securidaca longepedunculata Fers (Polygalaceae) is commonly used as a medicine in many parts of Africa and shows promise for protecting stored grain against insect pests. Analysis of a methanol extract of the root bark by gas chromatography linked to mass spectrometry (GC/MS) showed a major component accounting for over 90% of the volatile material. This was identified as methyl 2-hydroxybenzoate (methyl salicylate) by comparison of the GC retention times and mass spectrum with those of synthetic standards. This conflicts with an earlier report that the major component is methyl 4-hydroxybenzoate. Two minor components had mass spectra characteristic of 2-hydroxybenzoate esters and were identified as methyl 2-hydroxy-6-methoxybenzoate and its benzyl analogue, again conflicting with an earlier report.

Urinary protein excretion and expectant management of early onset, severe pre-eclampsia

OBJECTIVE

To evaluate the importance of proteinuria in the expectant management of early onset, severe pre-eclampsia.

METHODS

In this prospective series of 340 women, 24-h urine collections were performed and monitored twice weekly in a high-care ward.

RESULTS

Seventy-four women with at least two 24-h urine collections were grouped into women with a proteinuria increase of > or =2 g (n=29) and with women whose proteinuria decreased, or increased by <2 g (n=45). Major maternal complications, prolongation of gestation, and perinatal outcomes were comparable. Fifty-six (75%) women experienced an increase in proteinuria. When patients with heavy proteinuria (n=83) were compared to those with moderate proteinuria (n=257), maternal and perinatal outcomes were comparable. More days were gained before delivery in the heavy proteinuria group than in the moderate (12 vs. 9; P<0.001).

CONCLUSION

Most patients experienced increased proteinuria. Neither the rate of increase nor the amount of proteinuria affected maternal and perinatal outcomes.

High-average-power Nd:YAG planar waveguide laser that is face pumped by 10 laser diode bars

A planar waveguide Nd:YAG laser is pumped with 430 W of power from 10 laser diode bars to produce a multimode output power of 150 W at an optical efficiency of 35%. Use of a hybrid resonator of the positive-branch confocal unstable type for the lateral axis and of one of the near-case I waveguide type for the transverse axis increased the laser brightness by a factor of ~26 with only 12% less power than in the multimode case.

The effects of inadvertent intramuscular injection of BCG vaccine

We report on a case of inadvertent intramuscular injection of BCG vaccine into an already tuberculin-sensitive individual which resulted in a severe and prolonged local reaction. There is no consensus on the best management of this complication, although in this case healing appeared to be hastened by anti-tuberculous chemotherapy.

The crystal and molecular structures of diferric porcine and rabbit serum transferrins at resolutions of 2.15 and 2.60 A, respectively

The serum transferrins are monomeric proteins with a molecular mass of around 80 kDa and are responsible for the transport of iron in vertebrates. The three-dimensional structures of diferric porcine and rabbit serum transferrin have been refined against X-ray diffraction data extending to 2.15 and 2.60 A, respectively. Data for both proteins were collected using synchrotron radiation at temperatures of 277 K. The porcine protein crystallizes in the space group C2, with unit-cell parameters a = 223.8, b = 44.9, c = 78.9 A, beta = 105.4 degrees with one molecule in the asymmetric unit. The structure was solved by molecular-replacement methods using rabbit serum transferrin as the search model. The structure was refined using REFMAC, with a final residual of 13.8% (R(free) = 18.2% for a 5% data sample) for all data to 2.15 A. The final model comprises 5254 protein atoms, two Fe(3+) cations and two CO(3)(2-) anions, one N-acetyl glucosamine moiety and 494 water molecules. The rabbit protein crystallizes in space group P4(3)2(1)2, with unit-cell parameters a = 127.2, c = 144.9 A and one molecule per asymmetric unit. The structure was solved using the method of multiple isomorphous replacement and refined using REFMAC to give a final residual of 18.6% (R(free) = 22.2% for a 5% data sample) for all data to 2.60 A. The final model comprises 5216 protein atoms, two Fe(3+) cations and two CO(3)(2-) anions, a Cl(-) anion and 206 solvent molecules; there is no clear indication of the carbohydrate moiety attached to Asn490 (rabbit serum numbering). Both molecules adopt a bilobal structure typical for members of the transferrin family. Each of the structurally homologous lobes contains two dissimilar domains with a single iron-binding site buried within the interdomain cleft. The porcine serum protein lacks an interdomain disulfide bridge close to the connecting peptide between the lobes, but this seems to have little effect on the overall orientation of the lobes. The N-lobes of both proteins possess lysine residues, one from each of the two domains, that lie in close proximity to one another to form the so-called dilysine trigger. The more acid-labile release of iron from serum transferrins than from lactoferrins is discussed.

RadA protein from Archaeoglobus fulgidus forms rings, nucleoprotein filaments and catalyses homologous recombination

Proteins that catalyse homologous recombination have been identified in all living organisms and are essential for the repair of damaged DNA as well as for the generation of genetic diversity. In bacteria homologous recombination is performed by the RecA protein, whereas in the eukarya a related protein called Rad51 is required to catalyse recombination and repair. More recently, archaeal homologues of RecA/Rad51 (RadA) have been identified and isolated. In this work we have cloned and purified the RadA protein from the hyperthermophilic, sulphate-reducing archaeon Archaeoglobus fulgidus and characterised its in vitro activities. We show that (i) RadA protein forms ring structures in solution and binds single- but not double-stranded DNA to form nucleoprotein filaments, (ii) RadA is a single-stranded DNA-dependent ATPase at elevated temperatures, and (iii) RadA catalyses efficient D-loop formation and strand exchange at temperatures of 60-70 degrees C. Finally, we have used electron microscopy to visualise RadA-mediated joint molecules, the intermediates of homologous recombination. Intriguingly, RadA shares properties of both the bacterial RecA and eukaryotic Rad51 recombinases.

Female sex pheromone of brinjal fruit and shoot borer, Leucinodes orbonalis blend optimization

The brinjal fruit and shoot borer, Leucinodes orbonalis is the major pest of eggplant in South Asia. Analysis of female pheromone gland extracts prepared from insects of Indian and Taiwanese origin confirmed (E)-11-hexadecenyl acetate (E11-16:Ac) as the major pheromone component with 0.8 to 2.8% of the related (E)-11-hexadecen-1-ol (E11-16:OH), as previously reported from Sri Lanka. The average quantity of E11-16:Ac extracted per female was estimated to be 33 ng, with a range of 18.9 to 46.4 ng when collected 2 to 3 hr into the scotophase. In field trials conducted in India, blends containing between 1 and 10% E11-16:OH caught more male L. orbonalis than E11-16:Ac alone. At the 1,000 microg dose, on white rubber septa, addition of 1% E11-16:OH to E11-16:Ac was found to be more attractive to male L. orbonalis than either 0.1 or 10% E11-16:OH. Trap catch was found to be positively correlated with pheromone release rate, with the highest dose tested, 3,000 microg, on white rubber septa catching more male moths than lower doses. Field and wind tunnel release rate studies confirmed that E11-16:OH released from white rubber septa and polyethylene vials at approximately twice the rate of E11-16:Ac and that the release rate of both compounds was doubled in polyethylene vials compared to white rubber septa. This difference in release rate was reflected in field trials conducted in Bangladesh where polyethylene vial dispensers caught more male moths than either black or white rubber septa, each loaded with the same 100:1 blend of E11-16:Ac and E11-16:OH in a 3,000 microg loading.

Delivery of patients with early onset, severe pre-eclampsia

OBJECTIVES

To compare the effects of induction/labor to delivery before labor in early onset, severe pre-eclampsia.

METHODS

Five-year prospective case series. Delivery course and neonatal outcome were examined for 335 women with viable singletons.

RESULTS

Induction was successful in 45% of attempts. Women exposed to labor had longer (5.5 days, P<0.0001) admissions to delivery periods and were more often delivered for maternal indications (RR=2.87, 95% CI=1.98-4.16). Their babies were born 1.6 weeks older (P<0.0001) and 352 g heavier (P<0.0001) than those delivered before labor. Babies exposed to labor needed intensive care less often (RR=0.4, 95% CI=0.27-0.58), had lower rates of severe hyaline membrane disease (RR=0.26, 95% CI=0.11-0.59) and sepsis (RR=0.56, 95% CI=0.33-0.93), and were discharged earlier (P<0.0001).

CONCLUSIONS

Exposure to induction/labor in selected patients is not detrimental to neonatal outcome in early, severe pre-eclampsia.