Thermal simulation of pulsed direct laser interference patterning of metallic substrates using the smoothed particle hydrodynamics approach

This work presents a new approach to the thermal modelling of direct laser interference patterning (DLIP). The spatial and temporal evolution of the temperature distribution within metallic substrates, which are irradiated by nanosecond pulses during the DLIP process, is computed by means of a smoothed particle hydrodynamics (SPH) method. The developed model considers the conversion of laser energy into heat within a very thin surface layer, heat conduction into the bulk material and the effect of latent heat during involved phase transformations. The importance of proper determination of characteristic SPH parameters and adequate spatial resolution of the computational domain on the accuracy of the numerical solution is discussed in detail. The computed temperature distributions are in good agreement with the results of a previously developed FEM model and correspond very well to simultaneously performed experimental investigations.     

Ene Reductase‐Catalysed Synthesis of (R)‐Profen Derivatives

Enantiomerically pure (R)‐profen derivatives and intermediates are synthesised utilising the enzyme YqjM, an ene reductase from Bacillus subtilis. After optimisation of the reaction conditions, the chemoenzymatic approach was applied for the first time in the synthesis of (R)‐flurbiprofen methyl ester.     

Systems design means process precision,but emphasizes culture,value, and results

The issue: What does a comprehensive internal dispute resolution system look like? The problems: Is it current? Is it responsive? Is it effective? The perspective: Melanie Lewis, of Atlanta, describes how Coca‐Cola Enterprises Inc. assesses its conflict resolution needs, as well as how it implements, operates, and monitors its program–including provisions to redesign for new developments     

Direct laser interference patterning of planar and non-planar steels and their microstructural characterization

The direct laser interference patterning method was used to fabricate periodic structures on flat and cylindrical specimens of austenitic stainless steel (X5CrNi18-10) and martensitic bearing steel (100Cr6). In such laser processing the characterization of materials is a central issue. Therefore, this paper places special emphasis on the chemical, metallurgical and mechanical characterization of the laser processed metals. During the patterning process of 100Cr6, the carbides in the martensitic structure appear as elongated needles and become aligned to the direction of melt flow. The chemical composition analysis before and after laser interference patterning did not reveal any significant changes to either material. However, the surface hardness of 100Cr6 decreased when energy densities above 2.0 J/cm² were applied. For cylindrical specimens, the grating period changes with position along the circumference. The observed difference, however, is less than ～6.4% for rotation angles smaller than 20°.     

Hemocompatibility of diamondlike carbon–metal composite thin films

We have investigated the hemocompatibility of diamondlike carbon–silver composite and diamondlike carbon–titanium composite thin films prepared using a multicomponent target pulsed laser deposition process. These materials were examined using transmission electron microscopy, Raman spectroscopy, nanoindentation, electrochemical charge transfer testing, and platelet adhesion testing. Cross-sectional transmission electron microscopy revealed that silver self-assembles into nanoparticle arrays within the diamondlike carbon matrix in the diamondlike carbon–silver composite film. On the other hand, titanium self-assembles into alternating nanometer-thick titanium carbide layers within the diamondlike carbon matrix in the diamondlike carbon–titanium composite film. The hemocompatibility of these materials was examined using electrochemical charge transfer testing and platelet adhesion testing. A few small, widely scattered crystals were observed on the surface of the unalloyed diamondlike carbon film exposed to platelet rich plasma. On the other hand, dense fibrin networks with densely aggregated platelets were observed on the surfaces of diamondlike carbon–silver and diamondlike carbon–titanium composite thin films exposed to platelet rich plasma. Electrochemical testing revealed that the time constant for the diamondlike carbon thin film (λ = 1) was significantly higher than those for the diamondlike carbon–silver and diamondlike carbon–titanium composite thin films. These results suggest possible uses for diamondlike carbon thin films and diamondlike carbon–metal composite thin films as coatings in next generation cardiovascular implants.     

Aflatoxin and PAH exposure biomarkers in a U.S. population with a high incidence of hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is significantly elevated in a Hispanic community in Bexar County, Texas. Chronic exposure to dietary aflatoxins (AFs) is a major risk factor for HCC; increased risk has been linked to polycyclic aromatic hydrocarbon (PAH) co-exposure and hepatitis virus infection. The aims of this study were to assess AF and PAH exposures, investigate dietary factors that may contribute to increased AF exposure, and determine the prevalence of hepatitis virus infection in Bexar Co. Blood and urine samples were collected from 184 volunteers for biomarker analyses and hepatitis screening. Serum AFB₁-lysine adduct, urinary AFM₁ and 1-hydroxypyrene (1-OHP) levels were measured using high-performance liquid chromatography. The average AFB₁-lysine adduct level detected in 20.6% of serums was 3.84 ± 3.11 pg/mg albumin (range 1.01-16.57 pg/mg). AFM₁ was detected in 11.7% of urines, averaging 223.85 ± 250.56 pg/mg creatinine (range 1.89-935.49 pg/mg). AFM₁ detection was associated with increased consumption of corn tortillas (p = 0.009), nuts (p = 0.033) and rice (p = 0.037). A significant difference was observed between mean 1-OHP values of non-smokers (0.07 ± 0.13) and smokers (0.80 ± 0.68) μmol/mol creatinine (p < 0.01). A high hepatitis C virus positivity rate (7.1%) was observed. Findings suggest that the incidence and level of AF and PAH exposure were less than those observed in a high-risk population; however, participants consuming higher amounts of foods prone to AF contamination may be more vulnerable to exposure and interactions with other environmental/biological factors (i.e., HCV).     

Control and care: landlords and the governance of vulnerable tenants in houses in multiple occupation

Houses in multiple occupation (HMOs) in which tenants share facilities are housing an increasing proportion of vulnerable adults who have limited affordable housing options. However, knowledge about how these types of property are managed is limited. In this paper, we examine the governance function of HMO landlords from the perspective of landlords/landlord agents and the tenants that live within their properties. The landlord exercises control through formal and informal risk assessment of tenants and close surveillance of them. These control mechanisms may also involve direct or indirect provision of support and care to some tenants. This illustrates the complex relationship between care and control and the extent to which both are integral to the housing management of vulnerable tenants living in HMOs. We suggest that this dual function calls for a critical examination of what constitutes a ‘good landlord’.