Nonlinear mechanical response and rippling of thick multiwalled carbon nanotubes

The measured drop of the effective bending stiffness of multiwalled carbon nanotubes (MWCNTs) with increasing diameter is investigated by a generalized local quasicontinuum method. The previous hypothesis that this reduction is due to a rippling mode is confirmed by the calculations. The observed ripples result from a complex three-dimensional deformation similar to the Yoshimura buckling pattern. It is found that thick MWCNTs exhibit a well-defined nonlinear moment-curvature relation, even for small deformations, governed by the interplay of strain energy relaxation and intertube interactions. Rippling deformations are also predicted for MWCNTs subject to torsion, resulting in an effective torsional modulus much smaller than that predicted by linear elasticity.

Potential use of antioxidants for control of growth and fumonisin production by Fusarium verticillioides and Fusarium proliferatum on whole maize grain

The effect of interactions between two food grade antioxidants butylated hydroxyanisole (BHA) and propyl paraben (PP, 100, 200, 500 microg g(-1)) and water activity (a(w), 0.995, 0.98, 0.95) of irradiated maize on lag phase prior to growth, growth rate and fumonisin production by Fusarium verticillioides and Fusarium proliferatum was evaluated at 25 degrees C. Both antioxidants had an effect on growth characteristics, and fumonisin production. However, this was dependent on the dose used and the a(w) treatment. At 500 microg g(-1) BHA and PP increased the lag phase prior to growth, and reduced the growth rate of both Fusarium species significantly, especially at 0.95 a(w). Both antioxidants significantly reduced the production of fumonisin by both Fusarium species, especially at 0.98 and 0.95 a(w). These results suggest that these antioxidants have potential for treatment of maize grain for controlling growth of these mycotoxigenic species and prevent fumonisin accumulation.

Biotechnological applications of penicillin acylases: state-of-the-art

This review describes the most recent developments in the biotechnological applications of penicillin acylases. This group of enzymes is involved mainly in the industrial production of 6-aminopenicillanic acid and the synthesis of semisynthetic beta-lactam antibiotics. In addition, penicillin acylases can also be employed in other useful biotransformations, such as peptide synthesis and the resolution of racemic mixtures of chiral compounds. Particular emphasis is placed on advances in detection of new enzyme specificities towards other natural penicillins, enzyme immobilization, and optimization of enzyme-catalyzed hydrolysis and synthesis in the presence of organic solvents.

Comparison of dietary intake among overweight and non-overweight schoolchildren

OBJECTIVE

To determine differences in dietary intake between overweight and non-overweight schoolchildren and differences in consumption during the day and in the course of the week.

RESEARCH METHODS AND PROCEDURES

Using a cross-sectional design, 32 schoolchildren (11-y-old) were selected at random. The parents of children recorded dietary intake for a week using the food weighing method. The children were considered to be overweight when the weight for height was higher than 90th percentile.

RESULTS

Some 46.9% of examined schoolchildren were considered overweight. Percentage energy intake reported was significantly lower in the overweight group compared to the non-overweight children (8948.7 vs 9590.1 kJ/day; P<0.01). Carbohydrate intake was significantly greater in the non-overweight schoolchildren (250.9+/-58.8 vs 222.1+/-77.4 g/day; P<0.01). The difference in protein intake between week and weekend days was significant (81.6+/-25.5 in the week days vs 73.9+/-21.4 g/day in the weekend days; P<0.05).

DISCUSSION

The data suggest the belief that overweight children eat more than non-overweight children is not correct. These findings suggest that the positive energy balance causing overweight is due possibly to a low energy output.

Variability of six STR loci in populations from Central Spain

Allele frequency distributions of six short tandem repeat (STR) loci, HUMTH01, HUMFES/FPS, HUMTPOX, HUMVWF/A31, HUMF13B, and HUMLPL, were determined in a population (101 individuals) of the Vera-Jerte region in West Central Spain. Amplified products were electrophoresed on denaturing polyacrylamide gels and silver-stained. The exact test demonstrated that none of the six loci deviated from Hardy-Weinberg equilibrium. R-matrix analysis in relation to other European samples agrees well with genetic distance results of Reynolds et al. (1983). Comparisons show that our population comes reasonably well within the range of variation of other European samples, and that the representation of these samples on the genetic map indicates a close relation between geographical location and distribution in the diagram.

Subcutaneous emphysema during labour

Subcutaneous emphysema is an unusual but potentially dangerous complication of pregnancy and labour. The incidence is unknown. About 200 cases have been reported in world literature, mainly in primiparous women. This report describes a 30-year-old primigravid who complained during labour of a sudden swelling in her face associated with a mild difficulty in breathing.

Construction of a reference linkage map for melon

A map of melon (Cucumis melo L.) with 411 markers (234 RFLPs, 94 AFLPs, 47 RAPDs, 29 SSRs, five inter-SSRs, and two isozymes) and one morphological trait (carpel number) was constructed using the F2 progeny of a cross between the Korean accession P1161375 and the Spanish melon type 'Pinyonet Piel de Sapo'. RFLPs were obtained using 212 probes from different genomic and cDNA melon libraries, including 16 Arabidopsis ESTs, 13 Cucumis known genes, and three resistant gene homologues. Most loci (391) mapped to 12 major linkage groups, spanning a total genetic distance of 1197 cM, with an average map interval of 3 cM/marker. The remaining 21 loci (six RAPDs and 15 AFLPs) were not linked. A majority (66%) of the markers were codominant (RFLPs, SSRs, and isozymes), making them easily transferable to other melon crosses. Such markers can be used as a reference, to merge other melon and cucumber maps already constructed. Indeed, some of them (23 SSRs, 14 RFLPs, one isozyme, and one morphological trait) could act as anchor points with other published cucurbit maps.

Construction of a reference linkage map for melon

A map of melon (Cucumis melo L.) with 411 markers (234 RFLPs, 94 AFLPs, 47 RAPDs, 29 SSRs, five inter-SSRs, and two isozymes) and one morphological trait (carpel number) was constructed using the F2 progeny of a cross between the Korean accession PI161375 and the Spanish melon type 'Pinyonet Piel de Sapo'. RFLPs were obtained using 212 probes from different genomic and cDNA melon libraries, including 16 Arabidopsis ESTs, 13 Cucumis known genes, and three resistant gene homologues. Most loci (391) mapped to 12 major linkage groups, spanning a total genetic distance of 1197 cM, with an average map interval of 3 cM/marker. The remaining 21 loci (six RAPDs and 15 AFLPs) were not linked. A majority (66%) of the markers were codominant (RFLPs, SSRs, and isozymes), making them easily transferable to other melon crosses. Such markers can be used as a reference, to merge other melon and cucumber maps already constructed. Indeed, some of them (23 SSRs, 14 RFLPs, one isozyme, and one morphological trait) could act as anchor points with other published cucurbit maps.Key words: Cucumis melo, genetic map, molecular markers, RFLPs, SSRs.

Evaluation of Persian Gulf veterans with symptoms of peripheral neuropathy

BACKGROUND

Persian Gulf syndrome is a set of symptoms that do not fit into well-understood diagnostic categories. Among these symptoms, there are some that could suggest a generalized neuropathic process.

OBJECTIVE

Correlate neurological symptoms with objective electrodiagnostic findings.

METHODS

A randomized sample of 176 Persian Gulf veterans (PGV) evaluated at the San Juan Veterans Administration Medical Center was obtained. The subjects completed a questionnaire, and those who met the inclusion criteria underwent electrodiagnostic evaluation.

RESULTS

Of the 176 PGV selected, 162 completed the questionnaire. The next step was to perform electrodiagnostic studies on those who described symptoms suggesting peripheral neuropathy and met the inclusion criteria. Twelve individuals met the inclusion criteria for electro-diagnostic studies. All studies were normal except that two subjects were found to have bilateral carpal tunnel syndrome.

CONCLUSIONS

Although this is a relatively small sample of PGV, the findings are in accordance with other studies in which no definite generalized neuropathic pattern has been described.

Optimization of Composites Based on PP/Elastomer Blends and Short Pet Fibers

The physical and mechanical properties of ternary composites based on isotactic polypropylene (iPP) and ethylene—octene copolymer blends reinforced with poly(ethylene terephthalate) (PET) fibers have been studied. In order to evaluate the effect of the matrix composition and fiber content on the final properties of the composite, an experimental design based on a Doehlert Uniform Net has been employed. The results show that PET fibers behave as a reinforcing agent for PP/ethylene—octene copolymer blends, this effect being more evident at high copolymer percentages in the blend. It is important to notice that the analyzed mechanical properties are more dependent on matrix composition than on fiber percentage. So, as PP content is increased, the blend becomes more rigid and stable, and a noticeable increase in tensile and flexural modulus and strength are observed. Moreover, dynamic mechanical measurements provide a further confirmation of the reinforcing effect of these fibers. A displacement of the glass-transition temperature ((Tg)) of the elastomeric phase to higher temperatures is observed as fiber content in the composite increased. The morphology of the composites has been also analyzed by scanning electron microscopy (SEM). Good interfacial adhesion between fibers and matrix is observed, especially when the copolymer is the continuous phase. Hence, it is possible to correlate good interaction at the fiber—matrix interface with an improvement of composite properties.

Clinical, manometric, and EMG characteristics of patients with fecal incontinence

Fecal incontinence occurs frequently in both men and women. Yet, few studies on fecal incontinence have separated the evaluation and interpretation of data by gender. This study was designed to identify differences in the clinical, anorectal manometry, and electromyography (EMG) characteristics between male and female patients with fecal incontinence. We compared 53 incontinent males (mean age, 64 years) with 72 incontinent females (mean age, 61 years). Each patient underwent computerized anorectal manometry, and invasive (pudendal nerve conduction studies and concentric needle EMG) and noninvasive EMG (anal sensor surface electrode). An anal incontinence score (AIS) ranging from 0 to 6 was used to categorize patients. Male patients had higher incontinence scores at presentation (AIS greater than 4, 70% vs. 54%). Female patients had significantly lower resting pressure (40 vs. 53 mmHg, p < 0.05) and more women had sphincter asymmetry (36% vs. 25%, p < 0.05). Both groups had similar PNTMLs (2.41 vs. 2.47 ms). Difference was seen in the net strength of the sphincter (women 4.0 microV vs. men 8.0 microV, p < 0.05), as measured by noninvasive EMG. In conclusion, it is well known that there are differences in anorectal physiologic function between male and female patients with normal continence. Comparing male and female patients with fecal incontinence suggests that female patients tend to have worse sphincter function that men. Both groups had similar EMG alterations, suggesting a common neurogenic injury as etiology. Future studies are needed to address the sexes separately.

[Analysis of a programme of direct referral between primary and specialist care in potential surgery patients]

OBJECTIVE

To describe the results of a programme of direct referral of potential surgery patients between primary and specialist care, designed to lessen waiting-times.Design. Prospective, longitudinal and descriptive study.

SETTING

Health Area N. masculine 19 (Valencian Health Service): Surgery Service of Elche Hospital and 6 Health Centres.

PARTICIPANTS

Patients with pathologies that do not need special techniques for diagnosis except examination and who have a clear irrefutable indication of surgery without risk factors (ASA I-II).Intervention. The referral protocol consists of: a) diagnosis of pathology and pre-operative study in primary care (PC); b) appointment made by phone for the surgery clinic at the hospital, where diagnosis and pre-operative study are confirmed; c) referral and operation in the unit of non-hospital major surgery (UCMA); d) monitoring post-operation by the home hospitalisation unit (HHU) or preferably by the health centre, and e) check-up at the surgery clinic. Main measurements. The degree of agreement between PC and the specialist, assessment of the pre-operative study, and waiting time.

RESULTS

86 patients were referred (average age, 35; 76% male) by 28 doctors. The most common pathologies were hernia (36%), pilonidal sinus (23.2%) and miscellaneous (32.5%). There was general agreement in diagnosis in 90.7% of cases. 89.5% of patients brought the proper pre-operative study. Mean waiting time between the primary care consultation in the different procedures and the first hospital consultation was 19 days; with 44 more days elapsing till the surgical operation.

CONCLUSIONS

This new programme is effective and economic, in that there is <<adequate referral>> of patients, waiting time is reduced by over 7 months for pilonidal sinus and by over 2 years for hernia pathology, and the procedure can be used for a large number of patients, as the pathologies involved are very common.

Optimization of 6-aminopenicillanic acid (6-APA) production by using a new immobilized penicillin acylase

A new immobilized penicillin acylase (ECPVA) was obtained by covalent binding of penicillin acylase from Streptomyces lavendulae on Eupergit C. Enzymic hydrolysis of penicillin V catalysed by ECPVA was optimized using a 2(3) factorial design of experiments, and the selected parameters for this study were pH, temperature and substrate concentration. The immobilized enzyme showed an optimal pH value of 9.5-10.5, and an optimal temperature of 60 degrees C, whereas its soluble counterpart showed the same optimal pH value and a lower optimal temperature of 50 degrees C.

Cocaine self-administration in rats differentially alters mRNA levels of the monoamine transporters and striatal neuropeptides

The potential neuroadaptations to cocaine self-administration (SA) were evaluated using quantitative in situ hybridisation histochemistry. Levels of mRNAs of the monoamine transporters, i.e. the primary molecular targets of cocaine, and the striatal neuropeptides substance P and enkephalin, which predominantly exist in different populations of dopaminoceptive striatal neurons, were quantified in rats which had reached different stages of acquisition of cocaine SA. Thus, animals were killed 1 h after completing a self-administration session (i) early in or after acquisition of cocaine SA (ii) after various regimes of chronic cocaine SA, and (iii) a 10-day period of withdrawal from chronic cocaine intake. Control mRNA levels of all molecules under study were those quantified in animals receiving i.v. saline yoked to rats self-administering cocaine (1.5 or 0.75 mg/kg per infusion, depending on the experiment). Monoamine transporter expression was differentially altered by cocaine; dopamine transporter mRNA levels in the ventral tegmental area, but not in the substantia nigra, were increased following withdrawal from cocaine, suggesting a role for the upregulated mesolimbic dopamine transporter in the mechanisms underlying relapse to cocaine taking. By contrast, serotonin transporter mRNA in the dorsal raphé and noradrenaline transporter mRNA in the locus coeruleus remained unaltered under all experimental conditions. In addition, the expression of the striatal neuropeptides was also differentially altered; substance P mRNA levels were transiently increased in the shell of the nucleus accumbens by prolonged cocaine self-administration, but enkephalin mRNA levels in the dorsal and ventral striatum remained unaltered under all conditions.