Electronic and optoelectronic materials and devices inspired by nature.

Inorganic semiconductors permeate virtually every sphere of modern human existence. Micro-fabricated memory elements, processors, sensors, circuit elements, lasers, displays, detectors, etc are ubiquitous. However, the dawn of the 21st century has brought with it immense new challenges, and indeed opportunities-some of which require a paradigm shift in the way we think about resource use and disposal, which in turn directly impacts our ongoing relationship with inorganic semiconductors such as silicon and gallium arsenide. Furthermore, advances in fields such as nano-medicine and bioelectronics, and the impending revolution of the 'ubiquitous sensor network', all require new functional materials which are bio-compatible, cheap, have minimal embedded manufacturing energy plus extremely low power consumption, and are mechanically robust and flexible for integration with tissues, building structures, fabrics and all manner of hosts. In this short review article we summarize current progress in creating materials with such properties. We focus primarily on organic and bio-organic electronic and optoelectronic systems derived from or inspired by nature, and outline the complex charge transport and photo-physics which control their behaviour. We also introduce the concept of electrical devices based upon ion or proton flow ('ionics and protonics') and focus particularly on their role as a signal interface with biological systems. Finally, we highlight recent advances in creating working devices, some of which have bio-inspired architectures, and summarize the current issues, challenges and potential solutions. This is a rich new playground for the modern materials physicist.

Determination of paper filler Z-distribution by low-vacuum SEM and EDX.

Paper, mainly constituted of cellulose fibres, often contains mineral fillers. These fillers increase some of the properties of the paper (whiteness, printability, etc.) and are cheaper than the cellulose fibres. Nevertheless, the fillers reduce the mechanical properties of the sheet. Paper presents an anisotropy corresponding to three main directions. This anisotropy characterises the sheet mechanical properties, structure and filler distribution. Analyses of the cross section of the paper sheet with a low-vacuum scanning electron microscope with an energy dispersive spectrometer analysis module can show this distribution. The procedure developed consists in analysing discrete profiles to build the mean profile known as filler Z-distribution for each of the fillers. To develop this method, problems such as determination of the surface points, the number of points to analyse to define a cross section profile and the time required for the test, have been solved. Paper is sensitive to electron irradiation. In order to avoid deterioration of the material and to obtain satisfactory results, the time span for analyses is restricted to 40 s with a 12 kV electron beam accelerating voltage. Monte Carlo simulations are used to determine the diffusion cloud size and thus to determine the number of points that constitute a profile. The samples are gold sputtered and, with the aid of backscattered imaging, the coated surface allows determination of the sample surface points.

N-Acylethanolamines in seeds. Quantification Of molecular species and their degradation upon imbibition

N-Acylethanolamines (NAEs) were quantified in seeds of several plant species and several cultivated varieties of a single species (cotton [Gossypium hirstutum]) by gas chromatography-mass spectroscopy. The total NAE content of dry seeds ranged from 490 +/- 89 ng g(-1) fresh weight in pea (Pisum sativum cv early Alaska) to 1,608 +/- 309 ng g(-1) fresh weight in cotton (cv Stoneville 7A glandless). Molecular species of NAEs in all seeds contained predominantly 16C and 18C fatty acids, with N-linoleoylethanolamine (NAE18:2) being the most abundant (approaching 1,000 ng g(-1) fresh weight in cottonseeds). Total NAE levels dropped drastically following 4 h of imbibition in seeds of pea, cotton, and peanut (Arachis hypogea cv Virginia), and this decline was most pronounced for NAE18:2. A novel enzyme activity was identified in cytosolic fractions of imbibed cottonseeds that hydrolyzed NAE18:2 in vitro. NAE degradation was optimal at 35 degrees C in 50 mM MES buffer, pH 6.5, and was inhibited by phenylmethylsulfonyl fluoride and 5, 5'-dithio-bis(2-nitrobenzoic acid), which is typical of other amide hydrolases. Amidohydrolase activity in cytosolic fractions exhibited saturation kinetics toward the NAE18:2 substrate, with an apparent K(m) of 65 &mgr;M and a V(max) of 83 nmol min(-1) mg(-1) protein. Total NAE amidohydrolase activity increased during seed imbibition, with the highest levels (about four times that in dry seeds) measured 2 h after commencing hydration. NAEs belong to the family of "endocannabinoids," which have been identified as potent lipid mediators in other types of eukaryotic cells. This raises the possibility that their imbibition-induced metabolism in plants is involved in the regulation of seed germination.

The effect of salmeterol on nocturnal symptoms, airway function, and inflammation in asthma.

STUDY OBJECTIVE: To determine the efficacy of salmeterol alone in a group of patients with moderate asthma with nocturnal worsening of symptoms. DESIGN: Double-blind, randomized, placebo-controlled crossover study. SETTING: Tertiary care hospital specializing in respiratory diseases. PARTICIPANTS: Ten patients with nocturnal asthma. INTERVENTIONS: Subjects were randomized to salmeterol, 100 micrograms twice daily, or placebo for 6 weeks with a 1-week washout between treatment periods. Symptoms, nocturnal awakenings, and beta 2-agonist use were recorded daily. Spirometry was performed at weeks 1 and 6 of each period at bedtime and at 4 AM, and methacholine challenge was performed at 4 AM followed by bronchoscopy with BAL. BAL fluid analysis included cell count and differential count, eosinophil cationic protein, Charcot-Leyden crystal protein, leukotriene B4, and thromboxane B2. RESULTS: The percentage of nights with awakenings decreased significantly with salmeterol (69.8 +/- 8.7% vs 30.6 +/- 10.8% for placebo and salmeterol, respectively; p = 0.02). The percentage of 24-h days with supplemental inhaled beta 2-agonist use significantly decreased with salmeterol (85.9 +/- 9.4% vs 70.4 +/- 10.1% for placebo and salmeterol, respectively; p = 0.04). There were no significant differences in bronchial reactivity, 4 AM FEV1, overnight percentage change in FEV1, or indexes of airway inflammation. CONCLUSIONS: Salmeterol alone improves the number of nocturnal awakenings and supplemental 24-h beta 2-agonist use in nocturnal asthma without significantly altering lung function and airway inflammation.

Methacholine challenge does not affect bronchoalveolar fluid cell number and many indices of cell function in asthma.

Methacholine (MCh) challenge testing is often incorporated into clinical studies prior to performing bronchoscopy as a measure of bronchial hyperresponsiveness (BHR). However, the effect of methacholine on many aspects of bronchoalveolar lavage (BAL) fluid cell count and function have not been fully evaluated. Ten patients with asthma, maintained on inhaled beta 2-agonists, were studied. Each subject underwent two bronchoscopies in a random order, one preceded by methacholine challenge within 30 min of the BAL. The investigators were blinded to the regimen. Several markers of BAL fluid cell number and function were studied: cell count and differential histamine, eosinophil products, including eosinophil cationic protein and Charcot-Leyden crystal protein, macrophage production of thromboxane B2 and leukotriene B4, neutrophil lysozyme and lactoferrin, and lymphocyte typing and activation markers measured via flow cytometry. No significant differences were noted in any of these markers of cell number or function which could be ascribed to methacholine challenge. Thus, methacholine challenge does not appear to affect these markers of cell number and function. These findings indicate that a methacholine challenge can be used as a measure of bronchial hyperresponsiveness within 30 min prior to bronchoscopy without altering bronchoalveolar lavage fluid characteristics.

Localization of the cystic fibrosis transmembrane conductance regulator in airway secretory glands.

Cystic fibrosis (CF) is caused by mutations in the gene coding for the CF transmembrane conductance regulator (CFTR). From human normal tracheal submucosal gland cells in culture, we identified endogenous CFTR as a 170 kDa protein, consistent with that of fully glycosylated, mature CFTR molecule. This observation led to the hypothesis that airway secretory glands could be an important site for the CFTR expression. Using anti-human CFTR polyclonal and monoclonal antibodies, we examined the cellular and subcellular localization of the CFTR protein in airway submucosal glands from human and bovine tracheal tissues as well as in tracheal gland cell cultures. In human tracheal tissue, CFTR immunolabelling was present along both the apical and basolateral plasma membranes of glandular mucous cells. In contrast, CFTR was associated with the secretory granules of glandular serous cells. Using immunogold electron microscopy, we demonstrated that CFTR protein was more specifically associated with the membrane of serous cell secretory granules. In bovine tracheal tissue CFTR labelling was also identified in the secretory granules of glandular serous cells. In contrast, when bovine and human tracheal gland cells were cultured, no mature secretory granules were present, but a predominantly intracytoplasmic distribution of CFTR was observed. Our data thus suggest that in airway tissues, CFTR could be involved in intracellular processes of the mucus exocytosis in submucosal secretory glands.

New investigations on hematoxylin, hematein, and hematein-aluminium complexes. I. Spectroscopic and physico-chemical properties of hematoxylin and hematein.

Analytically pure hematoxylin (Htx), pentaacetylhematoxylin (PAHtx), and hematein (Hm) were isolated and characterized by 1H-NMR spectroscopy. The VIS/UV spectra of Htx and Hm were recorded in MeOH and in H2O at various pH values. The molar extinction coefficients of the long wavelength absorption bands are reported. The pKa value for the 1st acidic dissociation step of Hm has been determined from the pH dependency of the absorption spectra of Hm in aqueous buffer solutions. Finally, the absorption spectra are qualitatively discussed.

New investigations on hematoxylin, hematein, and hematein-aluminium complexes. II. Hematein-aluminium complexes and hemalum staining.

The absorption spectra of hematein-aluminium solutions have been recorded at various concentrations and pH values; the solutions were prepared using analytically pure hematein and potassium alum as aluminium source. In aqueous solution, four different hematein-aluminium complexes could be distinguished by absorption spectroscopy. In weakly acidic media we observed the violet 1:1 and 1:2 complexes HmAl (VII) and HmAl2(3) (VIII), and in strongly acidic solution the red 1:1 complex HmAl2 (IX). Whereas, in weakly alkaline solution the blue 1:1 complex HmAl0 (X) was detected. By change of the pH value the complexes were mutual interconverted. The dye complexes were characterized by their absorption spectra and molar extinction coefficients. We have stained HeLa cells with the complex solutions under different experimental conditions. In all cases the nuclear staining was intense whereas the staining of the cytoplasm was weak. The microspectra of the stained nuclei were recorded and compared with the absorption spectra of the complexes in solution. Thus it was possible to identify the bound dye species. After staining in acidic media, the cells were red to red-violet depending on the reaction conditions. The three cationic dye species VII, VIII, and IX were bound in varying amounts. After blueing in weakly acidic media or in water, only the violet dye complex VII was detected whereas, after blueing in weakly alkaline media, only the blue complex X has been observed. Enzymatic digestion experiments have shown that the dye complexes in the nuclei were bound to DNA while those in the cytoplasm and nucleoli were bound to RNA. The binding between the dye complexes and the nucleic acids is discussed.

Use corporate culture to trigger high performance.

The challenge is to manage the organization's culture so that you can tap the company's strengths to achieve superior performance and identify its weaknesses in time to overcome them before they cause serious damage.

Comparison of HIV-antibody prevalence in patients consenting to and declining HIV-antibody testing in an STD clinic.

All patients attending a sexually transmitted disease (STD) clinic were offered voluntary, anonymous human immunodeficiency virus (HIV)-antibody testing and counseling as part of routine clinical evaluation. During a three-month evaluation period, 82% of patients accepted HIV testing. Testing was accepted equally by men and women and by heterosexual and homosexual men. Black men were more likely to refuse testing than men from other ethnic groups. Eight (0.7%) of 1146 STD clinic patients tested were infected with HIV. A blinded study of 237 patients who refused testing identified nine (3.8%) additional HIV-infected patients. Men who refused testing were 5.3 times more likely to be infected than men who accepted testing. Male homosexuals and black and Hispanic men who refused testing were 7.3 and 8.8 times, respectively, more likely to be infected with HIV than were their counterparts who accepted testing. Human immunodeficiency virus testing and counseling should be routinely offered to STD clinic patients. Male STD clinic patients, especially homosexual or minority men, who refuse voluntary HIV testing should be counseled regarding reducing their risk for HIV transmission.

KIE: Results of voluntary, anonymous human immunodeficiency virus (HIV) antibody testing and counseling offered to all patients attending a sexually transmitted disease (STD) clinic showed that men who refused testing were 5.3 times more likely to be infected than men who accepted testing, and that male homosexuals and black and Hispanic men who refused testing were even more likely to be infected than their counterparts who accepted testing. The prevalence of HIV infection in persons refusing HIV testing was determined in a retrospective, blinded study using stored serum specimens originally drawn for syphilis testing. It is recommended that HIV testing and counseling should be routinely offered to STD clinic patients; male STD clinic patients who refuse voluntary HIV testing should be counseled about reducing their risk for HIV transmission.

The role of aging and chronic disease in sexual dysfunction.

Sexual dysfunction is so highly prevalent in elderly males that it is often considered an inevitable consequence of "normal aging." To determine if other factors are related to an age-associated decline in sexual function, we surveyed two groups of elderly male veterans in a geriatric ambulatory care clinic: aged 65 to 75 years ("young-old") and aged over 75 ("old-old"). We compared their survey responses with responses from a general medical clinic for unstable medical patients, aged under 65 ("old-young"). Of 347 subjects surveyed, 225 completed a health and sexual function questionnaire (response rate = 65%). Absent libido was reported by 30% of old-young, 31% of young-old, and 47% of old-old. Erectile dysfunction was reported in 26% of old-young, 27% of young-old, and 50% of old-old (P less than .01). We used ordinal logistic regression and found overall sexual dysfunction to be significantly related to subjective poor health, diabetes mellitus, and incontinence (P less than .05), while controlling for age. These data suggest that, although sexual dysfunction is more common in the aged, it is often related more to comorbid illness than aging alone.