Recovering the three-dimensional (3D) properties of artificial or biological systems using low X-ray doses is challenging as most techniques are based on computing hundreds of two-dimensional (2D) ...projections. The requirement for a low X-ray dose also prevents single-shot 3D imaging using ultrafast X-ray sources. Here we show that computed stereo vision concepts can be applied to X-rays. Stereo vision is important in the field of machine vision and robotics. We reconstruct two X-ray stereo views from coherent diffraction patterns and compute a nanoscale 3D representation of the sample from disparity maps. Similarly to brain perception, computed stereo vision algorithms use constraints. We demonstrate that phase-contrast images relax the disparity constraints, allowing occulted features to be revealed. We also show that by using nanoparticles as labels we can extend the applicability of the technique to complex samples. Computed stereo X-ray imaging will find application at X-ray free-electron lasers, synchrotrons and laser-based sources, and in industrial and medical 3D diagnosis methods.Stereo images of gold nanoparticles in a pyramid shape are reconstructed from X-ray coherent diffraction patterns. Depth information is retrieved by computing disparity maps without a priori knowledge of the sample shape.
This article discusses the limitations of root cause analysis (RCA) for surgical adverse events. Making sense of adverse events involves an appreciation of the unique features in a problematic ...situation, which resist generalization to other contexts. The top priority of adverse event investigations must be to inform the design of systems that help clinicians to adapt and respond effectively in real time to undesirable combinations of design, performance, and circumstance. RCAs can create opportunities in the clinical workplace for clinicians to reflect on local barriers and identify enablers of safe and reliable outcomes.
We report the first evaluation of bone quality in 70 thalassemia intermedia (TI) patients (37 males, 33 females, age 41 ± 12 years). Thirty-three patients (47%) had been transfused, 34 (49%) had been ...splenectomized, 39 (56%) were on iron chelation therapy, and 11 (16%) were on hydroxyurea. Mean hemoglobin was 9.2 ± 1.5 g/dl, median ferritin 537 ng/dl (range 14–4893), and mean liver iron concentration 7.6 ± 6.4 mg Fe/g dw. Fifteen patients (21%) had endocrinopathies, and 29 (41%) had vitamin D deficiency. Bone quantity (bone mineral density, BMD) and bone quality (trabecular bone score, TBS) were evaluated by densitometry. In 53/70 patients (76%), osteopathy was found (osteoporosis in 26/53, osteopenia in 27/53). BMD values were higher in the never-transfused patients and in the not-chelated group. A highly significant correlation was found between splenectomy and BMD at all the sites, with lower values in the splenectomized patients. TBS values were significantly lower in TI patients than in 65 non-thalassemic controls (1.22 vs 1.36,
p
< 0.01), mainly in those splenectomized and in the transfused and chelated groups (
p
< 0.01). TBS did not correlate with liver iron concentration values. Our data disclose the major role of non-invasive bone quality evaluation in TI patients, especially those with the worst health state, to obtain a comprehensive assessment of fracture risk. Splenectomy seems to play a major part in bone complications.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Academic and commercial branched polymer synthesis very commonly relies upon a repeating chemistry derived from a single monomer. Literature reports of branched homopolymers often rely upon ...chemistries that are difficult to scale. Step-growth polymerisations are widely utilised which also limit the molecular weight of resulting branched macromolecules. The recent reports of Transfer-dominated Branching Radical Telomerisation (TBRT) provide readily accessible routes to a range of previously inaccessible macromolecular architectures utilising free radical reactions but resulting in step-growth-like backbones. Here we show how TBRT may be used to form branched statistical copolymers with step-growth backbone chemistries using facile free radical reaction conditions through three novel synthesis strategies leading to new materials with readily tunable physical properties. The strategies are outlined conceptually, exemplified by experimental examples and determination of glass transition temperatures provides clear evidence of homogeneous statistical copolymer formation.
Three new synthesis strategies for branched statistical copolymers containing analogues of step-growth backbones are shown using free radical chemistries and transfer-dominated branching radical polymerisation (TBRT) conditions.
New branched polymerisations offer previously inaccessible macromolecules and architectural understanding is important as it provides insight into the branching mechanism and enables the ...determination of structure-property relationships. Here we present a detailed inverse gated
13
C NMR characterisation of materials derived from the very recently reported Transfer-dominated Branching Radical Telomerisation (TBRT) approach to quantify branching and provide an insight into cyclisation.
The characterisation and quantification of branching is key to understanding new complex macromolecules. Here we establish approaches to evaluate the unique and novel architectures formed by Transfer-dominated Branching Radical Telomerisation (TBRT).
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IJS, KILJ, NUK, UL, UM, UPUK
The commercial synthesis of polymers is generally limited to two main mechanisms that are typically considered to be mutually exclusive, namely step-growth and chain-growth polymerisation. This also ...defines the vast number of academic advances in macromolecular synthesis including the increasingly studied reversible deactivation radical polymerisation techniques (chain-growth) and complex polymer architectures such as dendrimers (step-growth). We report here a new synthetic strategy that utilises conventional free radical chain-growth chemistry, under modified telomerisation conditions, to form branched polymers containing chemistries conventionally formed under step-growth conditions. Telomerisation is typically limited to small molecule synthesis and employs addition across the unsaturated bond of a substrate, whilst minimising intermolecular reaction between substrates. Through the careful manipulation of reaction conditions, we have created a 'transfer dominated branching radical telomerisation' mechanism that creates branched polymers containing step-growth motifs from multi-vinyl monomers, with molecular weights in excess of 1000 kg mol
−1
, using industrially relevant free radical chain-growth chemistry. The scope of this approach is considerable, allowing access to entirely new macromolecular structures.
The commercially relevant synthesis of novel materials with step-growth backbones has been achieved by applying conventional chemistries to the radical telomerisation of divinyl monomers leading to high molecular weight branched polymers.
Objective. Data about endocrine and bone disease in nontransfusion-dependent thalassaemia (NTDT) is scanty. The aim of our study was to evaluate these complications in β-TI adult patients. Methods. ...We studied retrospectively 70 β-TI patients with mean followup of 20 years. Data recorded included age, gender, haemoglobin and ferritin levels, biochemical and endocrine tests, liver iron concentration (LIC) from T 2 * , transfusion regimen, iron chelation, hydroxyurea, splenectomy, and bone mineralization by dual X-ray absorptiometry. Results. Thirty-seven (53%) males and 33 (47%) females were studied, with mean age 41 ± 12 years, mean haemoglobin 9.2 ± 1.5 g/dL, median ferritin 537 (range 14–4893), and mean LIC 7.6 ± 6.4 mg Fe/g dw. Thirty-three patients (47%) had been transfused, occasionally (24/33; 73%) or regularly (9/33; 27%); 37/70 (53%) had never been transfused; 34/70 patients had been splenectomized (49%); 39 (56%) were on chelation therapy; and 11 (16%) were on hydroxyurea. Endocrinopathies were found in 15 patients (21%): 10 hypothyroidism, 3 hypogonadism, 2 impaired glucose tolerance (IGT), and one diabetes. Bone disease was observed in 53/70 (76%) patients, osteoporosis in 26/53 (49%), and osteopenia in 27/53 (51%). Discussion and Conclusions. Bone disease was found in most patients in our study, while endocrinopathies were highly uncommon, especially hypogonadism. We speculate that low iron burden may protect against endocrinopathy development.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
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