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Summary Background Maintenance of water balance in the stratum corneum (SC) is determined by the content of intercellular lipids and natural moisturizing factors (NMFs) in corneocytes. Aim To investigate the association between the NMFs and (pro)filaggrin and the proteases responsible for the processing of (pro)filaggrin to NMFs in the SC of hydrated and dry skin areas of healthy human subjects. Methods The SC hydration state and the transepidermal water loss (TEWL) were measured using a Corneometer and a Tewameter, respectively. Proteases, (pro)filaggrin and NMFs were extracted from SC samples obtained by tape-stripping of the tested skin. Expression levels of (pro)filaggrin were determined by dot blotting and western blotting, and total NMFs by ultra-high performance liquid chromatography. Expression of the proteases caspase-14, calpain-1 and bleomycin hydrolase was measured by western blotting. Results The levels of (pro)filaggrin were not significantly different between hydrated and dry skin, whereas the level of total NMFs was significantly reduced in dry skin. A negative correlation between (pro)filaggrin and NMFs was found in dry skin (Pearson correlation coefficient r = − 0.57, *P

This study evaluates the possibility of depositing hard B4C and TiC reinforcing particles in a Ni matrix using low-pressure cold spraying. It also investigates the effect of particle velocity and kinetic energy on deposition efficiency, microstructure, hardness, and wear resistance. B4C and TiC powders were blended at 50, 75, and 92 wt% carbide content with Ni powder comprising the remainder of the mixture. The impact velocity of sprayed carbide particles was calculated using a mathematical model based on the thermodynamics of compressible fluid flow through a converging-diverging nozzle. The model showed that the kinetic energy of TiC particles prior to impact was three times smaller than that of B4C, resulting in a higher carbide content (18 wt% compared to 8 wt%) due to reduced fracture and rebound of the TiC particles. Although the hardness values of both coatings are within the range of cold-sprayed WC-Co-Ni, wear rates were found to be high.

Background: Cathepsin G, a serine protease that is activated by ultraviolet (UV) radiation, increases matrix metalloproteinase-1 (MMP-1) expression in fibroblasts through fibronectin (Fn) fragmentation and promotes the conversion of proMMP-1 to active MMP-1. Objectives: This study investigated whether [2-[3-[[(1-benzoyl-4-piperidinyl)methylamino]carbonyl]-2-naphthalenyl]-1-(1-naphthalenyl)-2-oxoethyl]-phosphonic acid (KPA), a cathepsin G inhibitor, plays any role in extracellular matrix (ECM) damage in an in vitro 3D dermal equivalent (DE) and an in vivo ultraviolet B (UVB)-irradiated hairless mice. Methods: We examined the potential ECM-protective effects of a cathepsin G inhibitor in an in vitro 3D DE model and an in vivo UVB-irradiated hairless mouse skin model. Results: Among five known serine protease inhibitors, KPA showed the strongest potency and selectivity against cathepsin G. KPA inhibited the cathepsin G-mediated MMP-1 increase and alleviated the downregulation of mRNAs encoding collagen and tissue inhibitor of matrix metalloproteinase-1 in an in vitro 3D DE model. Most importantly, topical application of KPA (0.025%) to the dorsal skin of hairless mice enhanced collagen expression and attenuated UVB-induced Fn fragmentation and upregulation of MMP-2 and MMP-9 activities. Conclusions: Cathepsin G inhibitors may be useful for the prevention of UVB-induced photoaging through amelioration of ECM damage and MMP upregulation.

Nanostructures of self-assembled monolayers (SAMs) are designed and produced using coadsorption and nanografting techniques. Because the structures of these artificially engineered domains are predesigned and well-characterized, a systematic investigation is possible to study the mechanical responses to force modulation under atomic force microscope tips. Force modulation imaging reveals characteristic contrast sensitivity to changes in molecular-level packing, molecule chain lengths, domain boundaries, and surface chemical functionalities in SAMs. By means of actively tuning the driving frequency, the resonances at the tip-surface contact are selectively activated. Therefore, specific surface features, such as the edges of the domains and nanostructures or desired chemical functionalities, can be selectively enhanced in the amplitude images. These observations provide a new and active approach in materials characterization and the study of nanotribology using atomic force microscopy.

Aims The aims of this review were to assess the reasons why patients were referred to a specialist dental paediatric unit and the quality of the referral letters received. Material and Method All patients referred to the paediatric consultation clinic at the Liverpool University Dental Hospital from January 2004 to July 2004 were included in the review. The reasons for their referral, as stated by the referring practitioners, were compared with the clinical findings from initial assessments in the consultation clinic and the quality of referral letters was assessed. Results Ninety-nine out of a total of 102 referrals were from general dental practitioners. Sixty were girls and 42 boys. Their mean age was 9.5 years. The commonest reason (25 patients) was for treatment under general anaesthesia. In 90 (88.2%) cases the main reason for referral stated in the letters was consistent with the findings of the clinical assessment in the consultant clinic. All 102 letters included the patient's name, address, date of birth and telephone number and 89 (87.3%) were dated. However, only 25 (24.5%) included any mention of medical history and fewer than 30% included details of any treatment provided by the referring practitioner. Conclusions The vast majority of patients were referred for good reasons. The quality of the referral letters was generally poor. The use of a structured referral pro forma could improve the quality of the referral.

We demonstrate that it is possible to achieve exceptionally fine control over the anchoring of liquid crystals via the use of semi-fluorinated self-assembled monolayers of varying spacer length. We use this approach to map the detailed shape of an anchoring transition surface in thermodynamic phase space and to explore the links between anchoring and orientational wetting phenomena. These results allow one to design a substrate that will place a standard liquid-crystal film arbitrarily close to an anchoring transition between homeotropic and planar anchoring.

The structure and the electronic properties of a series of CH3- and CF3-terminated alkanethiol monolayers on Au(1 1 1) have been studied by scanning tunneling microscopy (STM) and surface X-ray and helium scattering. At full coverage, the CH3-terminated monolayers form long-range ordered domains of a ð p 3 � p 3ÞR30 and a ð2 p 3 � 3ÞR30 standing-up phase. By thermal desorption, distinct lying-down phases of intermediate density as well as the ðpp 3Þ lying-down phase were generated. In contrast, the CF3-terminated monolayers at full coverage form a standing-up phase of hexagonal symmetry that exhibits no long-range order at room temperature. Even after annealing, the domain sizes are smaller by more than one order of magnitude compared to the CH3-terminated thiol monolayers. A com- parison of the low-density lying-down phases suggests no measurable influence of the CF3-group on the ordering. The current-voltage dependence (I-V -curves) measured by scanning tunneling spectroscopy (STS) shows no voltage gap for CH3-terminated decanethiols. In contrast, in the I-V -curves for CF3-terminated decanethiol monolayers, an asym- metric voltage gap of about 2 V can be clearly observed. The latter results are discussed in terms of a microscopic model that includes the formation of an interfacial Coulomb barrier at the CF3/vacuum boundary. In addition, the effects of the tunneling conditions on the STM image contrast were examined. These studies demonstrate that the nature of the STM images and thus, the respective apparent lateral order of the films, strongly depends on the choice of the tunneling parameters. 2001 Elsevier Science B.V. All rights reserved.

We report the formation and subsequent topochemical polymerization of semi-fluorinated self-assembled monolayers (SAMs) containing diacetylene groups. The SAMs used were formed via the adsorption of the following derivatives: CF3(CF2)n(CH2)16C⋮CC⋮C(CH2)10SH (n = 2, 3) and CF3(CF2)n(CH2)11C⋮CC⋮C(CH2)10SH (n = 9, 12) onto the surface of gold. The polymerization of the monolayers was initiated by UV irradiation and was monitored using resonance Raman spectroscopy. SAMs with short semi-fluorinated portions were found to polymerize more effectively than those with longer portions, indicating that steric factors become important with increasing perfluorinated chain length.

The kinetics of the ruthenium-promoted cis,cis to trans,trans isomerization of 1,1,2,2,5,5,6,6-octamethyl-1,2,5,6-tetrasilacycloocta-3,7-diene were investigated. Incubation of a ruthenium alkylidene complex, (Cy(3)P)RuCl(2)(==CHPh)Ru(p-cymene)Cl(2), in CD(2)Cl(2) for 5 days at 40 degrees C afforded a catalytically active ruthenium species that was shown to be responsible for promoting the isomerization. The isomerization was observed to proceed in two steps: (1) conversion of the starting cis,cis isomer to a proposed cis,trans intermediate and (2) subsequent conversion of the intermediate to the product trans,trans isomer. Kinetic studies demonstrated that the two steps are first-order with respect to the concentrations of the cis,cis isomer, the intermediate, and the ruthenium alkylidene complex. The data were further consistent with a mechanism involving bimolecular hydride addition-elimination during the two isomerization steps.

The structures of semifluorinated alkanethiol self-assembled monolayers (SAMs) generated by the adsorption of CF3(CF2)9(CH2)nSH (F10HnSH, n = 2, 6, 11, 17, 33) onto gold were investigated with atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and surface plasmon resonance spectroscopy. Images obtained by AFM of the F10H2SH SAM showed a remarkably ordered 2D hexagonal lattice with a lattice constant, a = 5.9 ± 0.1 A, on Au(111)/mica. As the total number of carbon atoms in the alkyl spacer groups (n) was increased, the fluorocarbon adlayer structure appeared more disordered in the AFM images; however, the thicknesses of the fluorocarbon layers estimated from the C 1s (CF3), C 1s (CF2), and F 1s XPS signal intensities were indistinguishable in all of the SAMs. In contrast, the C 1s (CH2) signals revealed that the tilt angles of the alkyl spacer groups depended strongly on n. We utilized a contrast variation SPR technique with various contacting media for an independent determination of t...

The microstructure, wettability, and thermal stability of self-assembled monolayers (SAMs) on gold generated from semifluorinated alkanethiols F(CF2)10(CH2)nSH, where n = 2, 6, 11, 17, and 33 (F10HnSH), were examined by polarization modulation infrared reflection absoprtion spectroscopy (PM-IRRAS) and dynamic contact angle measurements. Analysis by PM-IRRAS revealed that the length of the methylene spacer (Hn) influenced the tilt angle of the fluorocarbon segments in the semifluorinated SAMs. As the length of the methylene spacer was increased, the tilt angle of the perfluorocarbon moiety increased with respect to the surface normal. The longer methylene spacers (Hn, n = 11, 17, and 33) exhibited well-ordered trans-extended conformations as indicated by the position of the antisymmetric methylene band (νaCH2 = 2919 cm-1). Shortening the length of the methylene spacer to n = 6, however, led to a decrease in conformational order (νaCH2 = 2925 cm-1). Dynamic contact angle measurements using the Wilhelmy plat...

This research was supported by the Office of Naval Research, Grant No. N00014-92-J-1246. Partial support from Division of Materials Research, NSF Polymer Program, Grants No. DMR92-23099 and DMR93-214573, is also appreciated. This work made use of MRL Central Facilities at UCSB supported by the National Science Foundation under award no. DMR96-32716. The work at NC State University was supported by the NCSU COE start-up funds and the NSF CAREER award, Grant No. DMR98-75256. The work at the University of Houston was supported by the National Science Foundation, Grant No. DMR97-00662. K.C. greatly acknowledges the financial support from the LG-Yonam Foundation for a sabbatical visit to Cornell University (1997-1998).

dc conductance measurements have been used to study the pinning of magnetic vortices by columnar defects in an amorphous film of Ta 0.35Ge0.65. Defects oriented at an angle of approximately 40° from the normal were introduced by oblique deposition of the film. The temperature dependence of the conductivity in the low current limit permits a direct comparison of pinning for magnetic fields oriented along and at large angles to the columns. The vortex mobility shows a minimum when the applied field is along the columnar defects, and there is a pronounced increase of the low current activation energy in that configuration at the matching field, i.e., when the defect and vortex densities are equal. At higher currents the I-V characteristics show a discontinuous increase to normal state resistance at a current density J*. The effect is demonstrated to result from an instability in the vortex viscosity for the field direction in which the vortices are weakly pinned, changing to a pinning instability for the field aligned along the columns. @S0163-1829~99!00141-1#

Utilizing scanning tunneling microscopy, we have explored the self-assembling and electronic properties of unsymmetrical disulfides CH3(CH2)nSS(CH2)n+lNC60 (where n = 5 or 10, and C60 = buckminster...

The chemisorption site of the simplest prototypical model alkanethiol compound, methanethiol [CH3SH], on a Pt{111} surface in the temperature range 298–1073 K has been investigated by means of time-of-flight scattering and recoiling spectrometry (TOF-SARS) and low-energy electron diffraction (LEED). TOF-SARS spectra of the scattered and recoiled ions plus fast neutrals were collected as a function of crystal azimuthal rotation angle δ and beam incident angle α using 4 keV Ar+ primary ions. At room temperature, the adsorption of methanethiol produces a partially disordered overlayer that gives rise to a diffuse (3×3)R30° LEED pattern and three-fold symmetry in the scattering profiles. Heating this surface layer results in the sequential dehydrogenation of the methanethiol and the formation of S–C species at elevated temperatures. By ∼373 K, hydrogen is absent from the TOF-SARS spectra and a sharp (3×3)R30° LEED pattern is observed. The model developed from the scattering data is consistent with the preservation of the adsorption site at elevated temperatures, but a change in the S–C bond angle with respect to the surface plane. For the fully dehydrogenated species, the S atoms reside ∼1.6±0.2 A above the surface in face-centered-cubic (fcc) three-fold sites and the C atoms reside ∼1.5±0.4 A in hexagonal-close-packed (hcp) three-fold sites. It is proposed that the remarkable stability of this SC adsorbate results from bonding of both the S and C atoms to the surrounding Pt atoms, i.e., a Pt-stabilized SC moiety.

An 8-question Modified Child Dental Anxiety Scale was developed to assess children's concerns about specific dental procedures. These dental situations include examination, scale and polish, injection, filling, extraction, and relative and general anaesthesia. A question about how the child felt generally when visiting the dentist was also included. Children ( n = 314) from two schools in Liverpool, ages 8 to 15 years, completed a questionnaire including the modified scale, Corah's Dental Anxiety Scale, the Dental Fear Survey Schedule for Children, and background questions (age, sex and previous dental experience). The internal consistency was favourable (α = .84) and test-retest reliability acceptable. This initial study suggests that the scale may be useful in trials to assess the benefits of interventions to assist children receive dental treatment.

Surface elemental and structural characterization of hexadecanethiol and heptadecanethiol (C and C for short) and 16,16,16-trifluorohexadecanethiol (FC) self-assembled monolayers (SAMs) on a Au111 surface have been obtained from time-of-flight scattering and recoiling spectrometry. The clean Au surface was also characterized in order to identify the azimuthal orientation of the SAMs with respect to the substrate. Classical ion trajectory simulations were used to relate the experimental scattering and recoiling data to the surface structure. The scattered and recoiled atoms originate from the outermost five-six atomic layers, and azimuthal anisotropy was observed in the measurements. The results provide a model for the SAMs in which the alkyl chains chemisorb with the S atoms situated above the face-centered-cubic (fcc) threefold sites of the Au111 surface to form a continuous film with a (√3×√3)R30° structure that fully covers the Au surface. The orientation of the molecular axis azimuth of the SAMs relative to the Au azimuthal directions was determined. The data indicate that the molecular chains have specific tilt and twist angles relative to the Au surface and six coexisting domains resulting from the six equivalent tilt directions of the molecular axis. Dramatic changes in the anisotropic patterns of the ion scattering azimuthal scans from the surfaces of the SAMs with different terminations were observed. These phenomena result from the different tilt angles of the CH and CF groups. The data are consistent with free rotation of both the CH and CF groups. The C SAM exhibited the best azimuthal features and was more resistant to radiation damage from the incident Ar scattering beam than the other films. Due to the tilt angle of the SAMs, an "ion's eye view" of the structure, i.e., the positions of the atomic cores as experienced by the incoming keV ions, reveals a regular array of sloping cavities within each unit cell.

The structure and growth of two classes of self-assembled monolayers (SAMs) on Au(111) derived from the adsorption of the functionalized thiol hexyl-azobenzenethiol (12-(4-(4-hexylphenylazo)phenoxy)dodecane-1-thiol) and the partially fluorinated alkanethiols (CF 3 (CF 2 ) 9 (CH 2 ) 11 SH and CF 3 (CF 2 ) 7 (CH 2 ) 6 SH were examined. The structural properties of the SAMs were strongly influenced by the interactions between the functional groups comprising the tails of the molecules. Molecular resolution atomic force microscopy (AFM) images of the hexyl-azobenzenethiol SAMs revealed an expanded lattice (nearest neighbor spacing, a = 0. 53 nm, b = 0. 56 nm, and angle between the two axes, φ = 85°) relative to those of simple azobenzene-terminated SAMs. The expanded lattice probably results from the presence of the hexyl tail groups. The structure of the SAMs formed from the fluorinated alkanethiols was also probed by AFM, Fourier transform infrared spectroscopy (FTIR-RAS) and dynamic contact angle measurements. The degree of molecular tilt of the fluorocarbon helix appears to be influenced by the length of the methylene spacer moieties, which might result from the introduction of flexibility into the molecular chains.

The paper describes the evolution of safety management and the part played by human factors in accident causation. It identifies the key elements of effective safety management and suggests that a crucial determinant of good safety performance is the safety culture of the organization. A plan is outlined for reviewing and improving safety culture with the support of a detailed safety culture promptlist.

Several studies have reported that 1,2-alkanediols show increasing anti-microbial activity as their alkane chain length increases. However, there are no reports on the influence of alkane chain length on the skin irritation potential of 1,2-alkanediols. To investigate the influence of alkane chain length on the skin irritation potential of 1,2-alkanediols. The objective and subjective (sensory) skin irritation potentials of five 1,2-alkanediols - 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and 1,2-decanediol - were evaluated. We also estimated percutaneous absorption by measuring in vitro skin penetration using a Franz diffusion cell system. Like anti-microbial activity, sensory irritation potential increased as alkane chain length increased, most likely due to increasing membrane interference and/or intrinsic toxicity of 1,2-alkanediols. 1,2-Hexanediol showed the lowest objective skin irritation potential, which increased when the alkane chain length decreased or increased. Furthermore, percutaneous absorption negatively correlated with the alkane chain length of 1,2-alkanediols. These results show that a lower skin absorption potential is not indicative of a low skin irritation potential. Our results suggest that the factors and processes involved in skin irritation potential are complex and that skin irritation potential is influenced by intrinsic toxicity and the potential for penetration or integration in the lipid bilayer.

We report a dramatic, concentration-dependent decrease in the rate of photo-oxidation of semiconducting polymers due to the addition of small amounts of metal nanoshells to the polymer. In each case, the nanoshell resonances are tuned to the triplet exciton-ground state energy of the polymer. The nanoshell dopants slow the oxidation rate yet do not affect the photoluminescent properties of the polymers to which they have been added.

This study has examined children's estimates of dental anxiety and pain before and after a standard dental treatment session consisting of a local analgesic and drilling procedures. A method of assessing intensity of pain while receiving dental treatment was devised, and measures of the child's uncooperativeness and the dentist's supportive behaviour including treatment time was collected. Results showed that there was an immediate reduction in dental anxiety following exposure to dental procedures for those children referred because of their previous uncooperativeness. The reduction in anxiety was not attributed to supportive behaviour of the dentist. Children referred as unco-operative recorded higher pain intensity to comparison children.

This paper describes research in two areas: heterogeneous catalysis and molecular self-assembly. The work in heterogeneous catalysis used the platinum-catalyzed hydrogenation of diolefin(dialkyl)platinum(II) complexes to generate platinum surface alkyls of known structure. The structure and reactivity of these suiface alkyls were inferred from characteristic processes occurring on the surface. The incorporation of deuterium from isotopically labelled protic solvents (e.g. EtOD) was particularly useful mechanistically. The technique of self-assembly was used to form organic monolayers by coordination of a ligand to a metal or metal oxide surface. In addition to the chemisorption of alkyl thiols on gold (as alkyl thiolates, RS-Au+), a number of other systems were demonstrated to givs ordered organic surface species.

This study examined bidirectional relationships between age at first sexual intercourse and academic goals and achievement. It was hypothesized that lower educational goals and achievement would be associated with initiating sexual intercourse at a younger age, and that initiating sexual activity early would be associated with a decrease in subsequent academic achievement and goals. In longitudinal data spanning 11 years, evidence was found for bidirectional effects. One interpretation of these results is that adolescents with high educational goals and achievement delay having intercourse because of the perceived risks (e.g., pregnancy and sexually transmitted diseases may jeopardize their plans for the future). Conversely, adolescents who engage in sexual intercourse at young ages might undergo a change in attitudes, including reduced interest in academic achievement and goals. The specific educational variables most strongly related to adolescent sexual intercourse in this study differed substantially by race and gender.

The fall in applications to dental schools in the UK has resulted in various recruiting strategies. One such move was the introduction of a two-day residential course for fifth and sixth formers which was first instigated in 1989. This paper describes the course which had been run on four occasions with a total of 160 participants. The results of a survey on the impressions of the course by these participants is reported. It appears that the courses are effective in increasing interest in dentistry in the vast majority of participants.

Nach einem auserhalb der Klinik stattgefundenen Herz-Kreislauf-Stillstand und zunachst erfolgreicher Reanimation sind die endgultigen Uberlebensraten und – bei den Uberlebenden – die neurologischen Ergebnisse weiterhin unbefriedigend. Dabei bleibt es schwierig, fruh das Outcome zu prognostizieren, da zuverlassige Marker fehlen. Ob die Serumlaktatkonzentration dabei hilfreich sein konnte, hat eine japanische Arbeitsgruppe untersucht.

A series of alkyl- and aryl-substituted derivatives of cis,cis-1,2,5,6-tetrasilacycloocta-3,7-diene were prepared. Isomerization of these compounds to the corresponding trans,trans-1,2,5,6-tetrasilacycloocta-3,7-dienes by exposure to Ru and Zr hydride complexes was explored. Experimental probes of the isomerization were consistent with a stepwise mechanism involving metal hydride addition/elimination rather than one involving radical intermediates. Analysis of the low energy conformers of the various cis and trans isomers of 1,1,2,2,5,5,6,6-octamethyl-1,2,5,6-tetrasilacycloocta-3,7-diene using density functional theory suggested the following trend in stability: trans,trans > cis,trans > cis,cis. The calculated trend in stability was consistent with the experimentally observed unidirectional isomerization of the carbon-carbon double bonds from all cis to all trans and supports a cis,trans isomer as a tenable intermediate.

Long-range interactions between self-assembled monolayers (SAMs) of semifluorinated alkanethiols have been studied by direct force measurements in water and aqueous NaCl solutions. SAMs prepared from three different thiols, with identical fluorinated head groups but varying hydrocarbon spacer lengths, were investigated: CF(3)(CF(2))(9)(CH(2))(x)SH, where x=2, 11, or 17. Force measurements show that the interactions in water and electrolyte solutions are composed of both double-layer interactions emerging from what appears to be charges adsorbed onto the surfaces and long-range "hydrophobic" attractions, in excess of the expected van der Waals forces. The three investigated thiols produce similar results in force measurements, though the contact angles with water are slightly different. The "hydrophobic" attraction has the form of step-like attractive discontinuities in the force profiles at separations ranging from 20 to 40 nm, caused by bridging of microscopic bubbles residing at the surfaces. The shape or range of these discontinuities are not significantly affected by replacement of the water with either 1 mM or 1 M NaCl solutions. The origin of the charges causing the electrostatic double-layer interaction is unclear, but some possible causes are discussed. Copyright 2001 Academic Press.

Self-assembled monolayers (SAMs) formed from semifluorinated alkanethiols (SFATs) CF3(CF2)9(CH2)nSH (F10HnSH: n = 2, 11, and 17) on poly-crystalline Au and Ag were characterized by X-ray photoelectron spectroscopy, infrared reflection absorption spectroscopy, and near edge X-ray absorption fine structure spectroscopy. SFATs were found to form highly ordered and densely packed SAMs on both substrates. The molecules are strongly bonded to the substrates via their sulfur head groups, in the same manner as conventional alkanethiol (AT) SAMs. The hydrocarbon (except for n = 2) and fluorocarbon parts of the adsorbed SFATs retain the expected planar zigzag and helical conformations of the respective bulk materials. The orientation of the fluorocarbon chains does not depend on the substrate. These entities are almost perpendicular to the substrate in F10H2S/Au and F10H2S/Ag and become slightly more tilted in SFAT SAMs with longer hydrocarbon moieties. However, the alkyl parts of the SFAT films exhibit tilt and twist angles that are similar to those of normal alkanethiol films on Ag and Au substrates despite the reduced packing density in the SFAT films as compared to normal AT SAMs. We suggest that the substrate-related differences in tilt and twist angles for both systems are associated with the different character of the head-group-substrate bonding on Au and Ag.

The Navy uses nitrite solution extensively as a rust preventing fluid in marine boiler maintenance operations. The Naval Facilities Engineering Service Center (NFESC) has developed a chemical reduction process for the treatment of wastewaters containing nitrite in concentrations exceeding water quality standard established by the United States Environmental Protection Agency (EPA).

The major focus of this research is the "Nanoengineering of Physical Properties of Materials". The goal is to learn to use molecular and nanoparticle building blocks to predictively design specific, highly controllable properties into materials that are not necessarily available in naturally occurring condensed-matter systems. The optical properties of composite nanoparticles called metal nanoshells are of particular interest in this context. Metal nanoshells are a new and unique type of composite nanoparticle that possesses physical properties of clear technological and defense-related importance. These properties include an extremely strong structure-dependent optical resonance that can be shifted across a remarkably broad range of the visible and the infrared regions of the spectrum. Our immediate objective is to extend our knowledge of the growth chemistry, molecular control, and optical properties of metal nanoshells and associated nanoparticle assemblies, both in dilute matrices and in nanoscale proximity to each other and to other optically active materials. This is a coordinated effort consisting of nanoparticle synthesis, molecular based assembly methods, optical characterization techniques, scanning probe microscopy, theory, and the demonstration of new functional materials and simple device structures.

The aim of this study was to determine the needs for dental information of adolescents and investigate the relationship of their desire for information with their opinion of who decides to make an appointment with the dentist (ie parent or child). In-depth interviews were conducted with 10 adolescents (aged 14 to 16 years) to derive questions for a questionnaire to assess dental information needs. One hundred and fifty-eight adolescents of similar age attending a secondary school in Liverpool were invited to complete the questionnaire. The results showed that adolescents are interested in finding out more information on different aspects of dental health which included especially: how to keep their teeth for life, about the best toothpaste, what to do in case they sustain dental injury and whether they required an orthodontic appliance. Another important finding was that more than half of the adolescents (57%) felt that they were responsible for taking decisions for their dental attendance. These children expressed a desire to know more about certain dental matters. Information needs of young people are important because of evidence derived from this study suggesting that acquisitiveness for dental information in this group, has possible implications for future patterns of seeking dental care.

We report the first active site substrate specificity analysis of a tyrosine-specific protein kinase, namely pp60c-src. Like the cAMP-dependent protein kinase and protein kinase C, pp60c-src will phosphorylate an assortment of achiral residues attached to active site-directed peptides. Furthermore, pp60c-src phosphorylates both aromatic and aliphatic alcohols. However, the substrate specificity of pp60c-src is much broader than that of the two previously examined serine/threonine-specific protein kinases. We have previously shown that both the cAMP-dependent protein kinase and protein kinase C will utilize a wide array of non-amino acid residues as substrates, as long as the distance between the hydroxyl moiety and the adjacent peptide backbone is comparable with that present in serine and threonine (Kwon, Y.-G., Mendelow, M., and Lawrence, D. S. (1994) J. Biol. Chem. 269, 4839-4844). In marked contrast, pp60c-src does not discriminate against substrates on the basis of chain length, catalyzing the phosphorylation of residues that contain anywhere from 2-12 carbons between the alcohol functional group and the adjacent peptide bond. In addition, pp60c-src phosphorylates L-serine in an active site-directed peptide. The possible structural basis for the multiple specificity of pp60c-src is discussed. Finally, the active site specificity of pp60c-src is not just limited to L-amino acid residues, but also extends into the realm of D-amino acids as well.

cAMP-dependent protein kinase substrates have been synthesized employing an unusually efficient method that allows the alcohol-bearing residue to be incorporated into the peptide after solid phase peptide synthesis. These peptide substrates have been utilized to map the active site substrate specificity of the protein kinase. Only alpha- or beta-substituted alcohol-bearing residues containing the proper absolute configuration are phosphorylated by the enzyme. However, the cAMP-dependent protein kinase will phosphorylate achiral residues. The implications of the observed protein kinase substrate specificity with respect to inhibitor design are discussed.

SynopsisThe collective expression of attitudes towards energy systems governs demand and hence cost, which combines with other factors to shape energy policy. For example, in the national debate over nuclear power, where decision makers either share the public's anxieties about costs and safety or are expediently responsive to them, there is a constant threat to political acceptance. The paper describes how perceived risks are one of the costs of all technologies and a brief summary is made of research on comparative risk perception. This confirms the wide disparities often observed between lay and expert risk assessments and provides some explanations. When attention is focussed on particular hazards, the concept of attitude becomes more appropriate than risk perception because choice behaviour is determined by overall evaluations and these are a trade off between perceived risks and benefits. Each of the latter is acquired from two overlapping classes of received knowledge, i.e. factual information (e.g. nuclear power comes from the fission of uranium atoms), and beliefs (e.g. nuclear power will create/reduce employment). In addition, the attitude acquires emotional associations and behavioural dispositions, forming an organised complex based on the environmental object. This structural approach facilities the “unpacking” of public attitudes towards energy systems into their constituents and this is essential for understanding, for consultation and for inducing attitude change.

The future likelihood of a hazardous event is predicted from its frequency per unit of past time or by aggregating the influence of the variables that determine it. It is assumed that accurate scientific measurement provides the best estimate, and that public perceptions, if discrepant, are ‘irrational’. Certainly, perception is a constructive process, dependent on partial information, selected again at the receptor stage and distorted in memory store. However, so-called ‘objective’ assessments generally subsume a limited range of variables, discount interactions and are biased to variables that are readily quantifiable for recording or future modelling. Extrapolation from the past rashly assumes stable continuity. In assessing ‘seriousness’ as distinct from probability, it may be argued that only the public can judge, since social and moral values are the ultimate criteria. Clearly, both objective and perceived assessments must be considered and eventually reconciled. The problems of measurement and a quest for lawfulness in the perception of risk are discussed.

Diseases of the blood and bone marrow are commonly associated with abnormalities of oxido-reductase and lysosomal enzymes within individual erythrocytes and leucocytes. There are considerable technical difficulties, however, in adapting enzyme histochemical techniques to the study of haemopoietic tissue since individual cells are readily disrupted during processing, show variable enzyme activity according to the stage of maturation, and possess a lipoprotein cytoplasmic membrane which hinders reagent penetration. Cytochemical techniques for the study of oxido-reductase systems are of importance in the study of the neutrophil in infected patients, the erythrocyte in glucose-6-phosphate dehydrogenase deficiency, and the primitive blast cell in acute leukaemia. Lysosomal enzymes are of importance in the study of the neutrophil in infected patients and in the differential diagnosis of acute leukaemia. Some examples of recent studies of these enzyme systems are given to illustrate technical procedures involving cytocentrifugation of cells on to glass slides, adjustment of the osmolality of the reaction mixture, and the study of smeared cells as opposed to cells incubated in suspension.

Although the social class characteristics of coloured immigrants in Britain are clearly defined, and while social class groups within the majority population display distinctive spatial patterns, very little recognition of the role of social class has been incorporated into studies of immigrant concentration and dispersal. This paper seeks to evaluate the spatial constraints on the dispersal of West Indians in London which are imposed by social class segregation within the wider population.

In the sixteen years since the last paper on this subject was published in the Journal (1951, 4, 288), some notable changes have taken place in the design and capabilities of submarines. Nautilus, the world's first nuclear submarine, was laid down in 1952 and completed in 1955. Since then a further 120 nuclear submarines have been commissioned. Now, a large proportion of the world's submarines are ‘true’ submersibles, self-sustaining over periods of months in everything except food; capable of proceeding submerged faster than the average surface ship; and rarely requiring to surface or even to come to periscope depth.

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Mechanisms based on one-electron oxidation appear incomplete in explaining cellular radiosensitization by nitroaromatic compounds such as misonidazole. Evidence is presented for a novel mechanism that may be involved in enhancing DNA strand breakage due to a variety of agents, including ionizing radiation, that generate carbon-centered radicals on DNA deoxyribose. Under anaerobic conditions the carbon-centered radical generated selectively at C-5' of deoxyribose of thymidylate residues in DNA by the antitumor antibiotic neocarzinostatin reacts with misonidazole to produce a DNA damage product in the form of 3'-(formyl phosphate)-ended DNA. In an 18O-transfer experiment we find that the carbonyl oxygen of the activated formyl moiety (trapped as formyl-Tris) is derived from the nitro group oxygen of misonidazole. This result strongly supports a mechanism in which a nitroxide radical adduct, formed by the addition of misonidazole to the radical at C-5' of deoxyribose, cleaves between the N and O so as to form an oxy radical precursor of the formyl moiety and a two-electron reduction species of misonidazole.