David Mills

Queen Mary, University of London | QMUL · Dental Physical Sciences

A Langmuir-Blodgett film of aliphatic substituted phthalocyanines on a C18 silane supporting layer coupled onto a silicon substrate has been investigated using neutron reflectometry. This multilayer structure is seen as a possible candidate for phthalocyanine-lipid biosensor devices. The results show the suitability of the C18 ligands as an anchori...

We have observed the formation of nanoscale Si spikes atop mesoscopic Si pillars during laser irradiation at intensities sufficiently high to melt silicon. The spikes have a radius on the order of 100 nm (<50 nm at the tip) and up to several micrometres in length. Nanoscale clusters formed during laser ablation deposit on the surface of the melt an...

High density mineralised protrusions (HDMP) from the tidemark mineralising front into hyaline articular cartilage (HAC) were first described in Thoroughbred racehorse fetlock joints and later in Icelandic horse hock joints. We now report them in human material. Whole femoral heads removed at operation for joint replacement or from dissection room c...

Since the development of X-Ray Microtomography in London Hospital Medical College (now part of Queen Mary University of London) in the 1980s, we have strived to increase our contrast resolution - to see features in the grey level of the images. We are now at the stage where we can see details that are invisible to commercial scanners. This lead us...

Computational flattening algorithms have been successfully applied to X-ray microtomography scans of damaged historical documents, but have so far been limited to scrolls, books, and documents with one or two folds. The challenge tackled here is to reconstruct the intricate folds, tucks, and slits of unopened letters secured shut with “letterlockin...

Armadillos are bitten by several species of flea. Females of the genus Tunga penetrate the epidermis and when in place are fertilised by males, after which the abdomen swells enormously to form a ‘neosome’. Within the penetrans group, T. perforans, makes lesions that perforate the osteoderms within the integument to form ~3 mm diameter cavities occ...

Objectives : Differences in the mineral concentration (MC) level of dental enamel may represent a precursor of white spot lesions adjacent to fixed orthodontic brackets. The aim of the current in vitro study was to compare the MC level central, occlusal and cervical to orthodontic attachments. Methods and Materials : A total of 16 enamel blocks we...

Human teeth are mechanically robust through a complex structural composite organisation of materials and morphology. Efforts to replicate mechanical function in artificial teeth (typodont teeth), such as in dental training applications, attempt to replicate the structure and morphology of real teeth but lack tactile similarities during mechanical c...

Inhalant use disorder is a psychiatric condition characterized by repeated deliberate inhalation from among a broad range of household and industrial chemical products with the intention of producing psychoactive effects. In addition to acute intoxication, prolonged inhalation of fluorinated compounds can cause skeletal fluorosis (SF). We report a...

Changes in trabecular micro-architecture are key to our understanding of osteoporosis. Previous work focusing on structure model index (SMI) measurements have concluded that disease progression entails a shift from plates to rods in trabecular bone, but SMI is heavily biased by bone volume fraction. As an alternative to SMI, we proposed the ellipso...

It is presently unclear why there is a high prevalence of periodontal disease (PD) in individuals living with chronic kidney disease (CKD). By employing three different models in rats and mice, we demonstrate that experimental uremia causes periodontal bone loss. Uremia alters the biochemical composition of saliva and induces progressive dysbiosis...

Changes in trabecular micro-architecture are key to our understanding of osteoporosis. Previous work focusing on structure model index (SMI) measurements have concluded that disease progression entails a shift from plates to rods in trabecular bone, but SMI is heavily biased by bone volume fraction. As an alternative to SMI, Ellipsoid Factor (EF) h...

The feasibility of a thin-wire torsion stress-strain experiment with nanostrain sensitivity is demonstrated. A gauge length of 50 m was made possible by using The Monument, London, thereby restoring it to its original purpose as a scientific instrument. A wire of 150 μm diameter was studied using the load-unload method, and data were recorded in th...

Fully revised, reordered and updated this is the latest book for those studying for their Intermediate Amateur radio licence. The Intermediate Licence Manual contains all of the information required for those seeking to upgrade their Foundation callsign. Designed to cover all elements of the Amateur Radio Intermediate licence syllabus, this second...

As a part of the European Union BIOMED I study “Assessment of Bone Quality in Osteoporosis,” Sixty-nine second lumbar vertebral body specimens (L2) were obtained post mortem from 32 women and 37 men (age 24–92 years). Our initial remit was to study variations in density of the calcified tissues by quantitative backscattered electron imaging (BSE-SE...

Objectives:: The objective of this in vitro study was to quantify the amount of mineral change in demineralized dentin at pH 5.5 after the application of dental varnishes containing fluoride with casein phosphopeptide-amorphous calcium phosphate, fluoride and bioglass, or fluoride alone. Methods and materials:: A total of 12 extracted human soun...

There is a large body of historical documents that are too fragile to be opened or unrolled, making their contents inaccessible. Recent improvements in X-ray scanning technology and computer vision techniques make it possible to perform a "virtual" unrolling of such documents. We describe a novel technique to process a stack of 3D X-ray images to i...

Artificial teeth have several advantages in preclinical training. The aim of this study is to three‐dimensionally (3D) print accurate artificial teeth using scans from X‐ray microtomography (XMT). Extracted and artificial teeth were imaged at 90 kV and 40 kV, respectively, to create detailed high contrast scans. The dataset was visualised to produc...

Ancient Egyptian mummies were often covered with an outer casing, panels and masks made from cartonnage: a lightweight material made from linen, plaster, and recycled papyrus held together with adhesive. Egyptologists, papyrologists, and historians aim to recover and read extant text on the papyrus contained within cartonnage layers, but some metho...

Objectives: The immediate aim of this study was to develop and test a method to record, visualize and quantify real-time demineralization (or remineralization) of teeth in vitro using X-ray microtomography (XMT or micro-CT). The longer term objective is to improve understanding of demineralization processes, allowing the creation of better artific...

1960s film was typically printed on tri-acetate film base. If not preserved properly, such material breaks down at a chemical level, which is a non-stoppable process that permanently fuses the film so that it essentially becomes a lump of solid plastic. Recently, some precious films, such as the only known copy of the earliest surviving episode of...

The authors have previously published a method of beam hardening correction for X-ray microtomography that allows accurate determination of mineral concentration in hard tissue. This uses a multi-element calibration carousel for making experimental X-ray attenuation measurements to optimise the parameters in a model of X-ray transmission and detect...

In laboratory X-ray microtomography (XMT) systems, the signal-to-noise ratio (SNR) is typically determined by the X-ray exposure due to the low flux associated with microfocus X-ray tubes. As the exposure time is increased, the SNR improves up to a point where other sources of variability dominate, such as differences in the sensitivities of adjace...

"Can brute-force high-contrast tomography techniques and image processing techniques retrieve textual content from damaged heritage materials?" The Dental Institute at Queen Mary University of London (QMUL) is the leading centre for very high contrast X-Ray Microtomography imaging. The Apocalypto Project is our collaboration with the heritage commu...

The potential use of high contrast X-ray microtomography (XMT) for the reading of fragile historic documents without the need to physically unravel them is a new analytical imaging development in the field of conservation however, it is important to first assess if there is any evidence of change in the parchment structure during scanning by XMT. M...

Stored in various public archives and private collections around the world, there are untold numbers of documents whose content is lost to memory and history. They cannot be read by normal means, because the parchment and paper they are written on has degraded; any attempt to handle or process the document for reading will at the very least cause i...

The goal of the MuCAT scanner development at Queen Mary University of London is to provide highly accurate maps of a specimen’s X-ray linear attenuation coefficient; speed of data acquisition and spatial resolution having a lower priority. The reason for this approach is that the primary application is to accurately map the mineral concentration in...

Impact-source X-ray microtomography (XMT) is a widely-used benchtop alternative to synchrotron radiation microtomography. Since X-rays from a tube are polychromatic, however, greyscale ‘beam hardening' artefacts are produced by the preferential absorption of low-energy photons in the beam path. A multi-material ‘carousel' test piece was developed...

In 1981, Elliott and Dover designed an X-ray microtomography scanner as a means of measuring the local mineral concentration in teeth. Although slow, this first generation system gave accurate measurements of the X-ray linear attenuation coefficient (LAC) due to its use of energy dispersive photon counting apparatus. Attaining such accuracy with in...

The level-1 calorimeter trigger consists of three subsystems, namely the Preprocessor, electron/photon and tau/hadron Cluster Processor (CP), and Jet/Energy-sum Processor (JEP). The CP and JEP will receive digitised calorimeter trigger-tower data from the Preprocessor and will provide trigger multiplicity information to the Central Trigger Processo...

Excimer laser ablation at 308 nm has been used to texture the surfaces of a variety of materials of interest for optoelectronic and biotechnological applications. Using a range of pre- and post-processing methods, we are able to produce nano-, micro- and meso-scale features over large areas rapidly in materials such as crystalline Si, porous silico...

Etching of silicon can be accomplished in a number of ways: in aqueous solutions of fluoride or KOH, or by simultaneous exposure to a gas such as SF6 or HCl and high power laser irradiation. Here we review how laser assisted etching, chemically enhanced laser ablation, and stain etching can be used to create pillars, pores, porosified pillars, and...

We used a XeCl excimer laser (308 nm, ∼3 J cm–2) and chemically enhanced laser ablation in the presence of SF6 to create arrays of silicon pillars. Etching of these pillars with KOH leads to arrays of macropores whose morphology depends on surface crystallography. Several new stain etchants – containing some combination of HF, NH4HF2, HCl, HNO3, Fe...

Micrometre-scale Si pillars are formed by chemically enhanced laser ablation using nanosecond excimer laser irradiation of a Si single crystal in the presence of SF6. We demonstrate the importance of precursor holes in determining the positioning of the pillars and show that we can control the initiation of precursor holes by ruling a grating into...

Mesoscale silicon pillars are formed when silicon wafers are irradiated by a nanosecond excimer laser operating at 308 nm and incident fluence of similar to3 J cm(-2). The morphology of the pillars responds to the chemical composition of the gas phase above the Si surface. Postprocessing can also be used to change the structure of the pillars. We d...

At the full LHC design luminosity of , there will be approximately 109 proton–proton interactions per second. The ATLAS level-1 trigger is required to have an acceptance factor of ∼10−3. The calorimeter trigger covers the region |η|⩽5.0, and φ=0 to 2π. The distribution of transverse energy over the trigger phase space is analysed to identify candid...

The final Pre-Precessor Multi-Chip Module (PPrMCM) of the ATLAS Level-1 Calorimeter Trigger is presented. It consists of a four-layer substrate with plasma-etched vias carrying nine dies from different manufacturers. The task of the system is to receive and digitize analog input signals from individual trigger towers, to perform complex digital sig...

The Level-1 Calorimeter Trigger consists of a Preprocessor, a Cluster Processor (CP), and a Jet/Energy -sum Processor (JEP). The CP and JEP receive digitised trigger-tower data from the Preprocessor and produce trigger multiplicity and region-of-interest (RoI) information. The CP Modules (CPM) are designed to find isolated electron/photon and hadro...

The architecture of the ATLAS Level-1 Calorimeter Trigger has been improved and simplified by using a common module to perform different functions that originally required three separate modules. The key is the use of FPGAs with multiple configurations, and the adoption by different subsystems of a common high-density custom crate backplane that ta...