Cystathionine beta-synthase (CBS) deficiency is a rare inherited disorder in the methionine catabolic pathway, in which the impaired synthesis of cystathionine leads to accumulation of homocysteine. ...Patients can present to many different specialists and diagnosis is often delayed. Severely affected patients usually present in childhood with ectopia lentis, learning difficulties and skeletal abnormalities. These patients generally require treatment with a low-methionine diet and/or betaine. In contrast, mildly affected patients are likely to present as adults with thromboembolism and to respond to treatment with pyridoxine. In this article, we present recommendations for the diagnosis and management of CBS deficiency, based on a systematic review of the literature. Unfortunately, the quality of the evidence is poor, as it often is for rare diseases. We strongly recommend measuring the plasma total homocysteine concentrations in any patient whose clinical features suggest the diagnosis. Our recommendations may help to standardise testing for pyridoxine responsiveness. Current evidence suggests that patients are unlikely to develop complications if the plasma total homocysteine concentration is maintained below 120 μmol/L. Nevertheless, we recommend keeping the concentration below 100 μmol/L because levels fluctuate and the complications associated with high levels are so serious.
Whilst titanium, stainless steel, and cobalt-chrome alloys are the most common materials for use in orthopaedic implant devices, there are significant advantages in moving to alternative non-metallic ...substrates. Substrates such as polymers may have advantageous mechanical biological properties whilst other substrates may bring unique capability. A key challenge in the use of non-metal products is producing substrates which can be modified to allow the formation of well-adhered hydroxyapatite films which promote osteointegration and have other beneficial properties. In this work, we aim to develop methodology for the growth of hydroxyapatite films on surfaces other than bulk metallic parts using a wet chemical coating process, and we provide a detailed characterisation of the coatings. In this study, hydroxyapatite is grown from saturated solutions onto thin titanium films and silicon substrates and compared to results from titanium alloy substrates. The coating process efficacy is shown to be dependent on substrate roughness, hydrophilicity, and activation. The mechanism of the hydroxyapatite growth is investigated in terms of initial attachment and morphological development using SEM and XPS analysis. XPS analysis reveals the exact chemical state of the hydroxyapatite compositional elements of Ca, P, and O. The characterisation of grown hydroxyapatite layers by XRD reveals that the hydroxyapatite forms from amorphous phases, displaying preferential crystal growth along the 002 direction, with TEM imagery confirming polycrystalline pockets amid an amorphous matrix. SEM-EDX and FTIR confirmed the presence of hydroxyapatite phases through elemental atomic weight percentages and bond assignment. All data are collated and reviewed for the different substrates. The results demonstrate that once hydroxyapatite seeds, it crystallises in the same manner as bulk titanium whether that be on a titanium or silicon substrate. These data suggest that a range of substrates may be coated using this facile hydroxyapatite deposition technique, just broadening the choice of substrate for a particular function.
This study introduces and explores the use of supersaturated solutions of calcium and phosphate ions to generate well-defined hydroxyapatite coatings for orthopaedic implants. The deposition of ...hydroxyapatite is conducted via several solutions of metastable precursors that precipitate insoluble hydroxyapatite minerals at a substrate–solution interface. Solutions of this nature are intrinsically unstable, but this paper outlines process windows in terms of time, temperature, concentration and pH in which coating deposition is controlled via the stop/go reaction. To understand the kinetics of the deposition process, comparisons based on ionic strength, particle size, electron imaging, elemental analyses and mass of the formed coating for various deposition solutions are carried out. This comprehensive dataset enables the measurement of deposition kinetics and identification of an optimum solution and its reaction mechanism. This study has established stable and reproducible process windows, which are precisely controlled, leading to the successful formation of desired hydroxyapatite films. The data demonstrate that this process is a promising and highly repeatable method for forming hydroxyapatites with desirable thickness, morphology and chemical composition at low temperatures and low capital cost compared to the existing techniques.
This study is the second part of a two-part study whereby supersaturated solutions of calcium and phosphate ions generate well-defined hydroxyapatite coatings for orthopaedic implants. An ‘ideal’ ...process solution is selected from Part 1, and the detailed characterisation of films produced from this solution is undertaken here in Part 2. Analysis is presented on the hydroxyapatite produced, in both powder form and as a film upon titanium substrates representative of orthopaedic implants. From thermal analysis data, it is shown that there is bound and interstitial water present in the hydroxyapatite. Nuclear magnetic resonance data allow for the distinction between an amorphous and a crystalline component of the material. As hydroxyapatite coatings are generated, their growth mechanism is tracked across repeated process runs. A clear understanding of the growth mechanism is achieved though crystallinity and electron imaging data. Transmission electron imaging data support the proposed crystal growth and deposition mechanism. All of the data conclude that this process has a clear propensity to grow the hydroxyapatite phase of octacalcium phosphate. The investigation of the hydroxyapatite coating and its growth mechanism establish that a stable and reproducible process window has been identified. Precise control is achieved, leading to the successful formation of the desired hydroxyapatite films.
Gallium oxide has known beneficial osteo-integrative properties. This may have importance for improving the osteointegration of orthopedic implants. At high concentrations gallium is cytotoxic. ...Therefore, integration of gallium into implant devices must be carefully controlled to limit its concentration and release. A strategy based on surface doping of gallium although challenging seems an appropriate approach to limit dose amounts to minimize cytotoxicity and maximize osteointegration benefits. In this work we develop a novel form of patterned surface doping via a block copolymer-based surface chemistry that enables very low gallium content but enhanced osteointegration as proven by comprehensive bioassays. Polystyrene-b-poly 4vinyl pyridine (PS-b-P4VP) BCP (block copolymer) films were produced on surfaces. Selective infiltration of the BCP pattern with a gallium salt precursor solution and subsequent UV-ozone treatment produced a surface pattern of gallium oxide nanodots as evidenced by atomic force and scanning electron microscopy. A comprehensive study of the bioactivity was carried out, including antimicrobial and sterility testing, gallium ion release kinetics and the interaction with human marrow mesenchymal stomal cells and mononuclear cells. Comparing the data from osteogenesis media assay tests with osteoclastogenesis tests demonstrated the potential for the gallium oxide nanodot doping to improve osteointegration properties of a surface.
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•Block copolymer pattern used to generate novel orthopaedic coating.•Extensive characterisation of gallium nanodot coating and biological assay tests.•Controlled release of gallium ions from coating improves osteointegration.•No effect on monocyte viability but 88% reduction in osteoclast formation.
The objectives of this study were to develop composite films using various gelatin sources with corn oil (CO) incorporation (55.18%) and to investigate the mechanical and physical properties of these ...films as potential packaging films. There were increases (
< 0.05) in the tensile strength (TS) and puncture strength (PS) of films when the concentration of gelatin increased. The mechanical properties of these films were also improved when compared with films produced without CO. Conversely, the water barrier properties of composite films decreased (
< 0.05) when the concentration of gelatin in composite films increased. Comparing with pure gelatin films, water and oxygen barrier properties of gelatin films decreased when manufactured with the inclusion of CO.
Bulk titanium and CoCr are the most common metals for use in orthopedic implants, but there are significant advantages in alternative substrates. Research in the last decade has focused on various ...alternatives; however, these materials are hindered by the adhesion of hydroxyapatite layers to non-bulk metal parts. Demonstrated in this work is the ability to grow hydroxyapatite on surfaces other than bulk metallic parts through the process and characterisation of coating properties. In this study, hydroxyapatite (HA) is grown from saturated solution onto thin titanium films and silicon substrates. Its efficacy is shown to be dependent on substrate roughness. The mechanism of the hydroxyapatite growth is investigated in terms of initial attachment and morphological development using SEM analysis. Characterisation of hydroxyapatite layers by XRD demonstrates how the hydroxyapatite forms from amorphous phases to preferential crystal growth along the 002 direction and TEM imagery confirms specific d-spacings. SEM-EDX and FTIR show adherence to known HA phases through elemental atomic weight percentages and bond assignment. All data are collated and reviewed through the lens of different substrates. The results suggest that once hydroxyapatite seeds, it grows identically regardless of substrate.
Observation of a New Ξ b − Resonance Albrecht, J.; Amerio, S.; d’Argent, P. ...
Physical review letters,
08/2018, Letnik:
121, Številka:
7
Journal Article
Recenzirano
Odprti dostop
From samples of pp collision data collected by the LHCb experiment at s=7, 8 and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0 and 1.5 fb−1, respectively, a peak in both the Λb0K− and ...Ξb0π− invariant mass spectra is observed. In the quark model, radially and orbitally excited Ξb− resonances with quark content bds are expected. Referring to this peak as Ξb(6227)−, the mass and natural width are measured to be mΞb(6227)−=6226.9±2.0±0.3±0.2 MeV/c2 and ΓΞb(6227)−=18.1±5.4±1.8 MeV/c2, where the first uncertainty is statistical, the second is systematic, and the third, on mΞb(6227)−, is due to the knowledge of the Λb0 baryon mass. Relative production rates of the Ξb(6227)−→Λb0K− and Ξb(6227)−→Ξb0π− decays are also reported.
The Dalitz plot analysis technique is used to study the resonant substructures of B−→D+π−π− decays in a data sample corresponding to 3.0 fb−1 of pp collision data recorded by the LHCb experiment ...during 2011 and 2012. A model-independent analysis of the angular moments demonstrates the presence of resonances with spins 1, 2 and 3 at high D+π− mass. The data are fitted with an amplitude model composed of a quasi-model-independent function to describe the D+π− S wave together with virtual contributions from the D*(2007)0 and B*0 states, and components corresponding to the D2*(2460)0, D1*(2680)0, D3*(2760)0 and D2*(3000)0 resonances. The masses and widths of these resonances are determined together with the branching fractions for their production in B−→D+π−π− decays. The D+π− S wave has phase motion consistent with that expected due to the presence of the D0*(2400)0 state. These results constitute the first observations of the D3*(2760)0 and D2*(3000)0 resonances, with significances of 10σ and 6.6σ, respectively.
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