bluuebunny/crossref_metadata_2025_split huggingface dataset:
Risk factors for thrombosis in patients with immune mediated heparin‐induced thrombocytopenia
Authors: Fabris F. , Luzzatto G. , Soini B. , Ramon R. , Scandellari R. , Randi M. L. , Girolami A. 
Published: March 2003

Abstract. Fabris F, Luzzatto G, Soini B, Ramon R, Scandellari R, Randi ML, Girolami A (University of Padua Medical School, Padova, Italy). Risk factors for thrombosis in patients with immune mediated heparin‐induced thrombocytopenia. J Intern Med 2002; 252: 149–154. Background. As reported by major clinical series in the literature, about 2% of patients receiving unfractionated heparin (UFH) develop immune‐mediated (type II) heparin‐induced thrombocytopenia (HIT) that may be complicated in 30–75% of cases by a paradoxical thrombotic syndrome (HITTS), either arterial or venous. HITTS carries relevant rates of mortality and morbidity, amongst which cerebral and/or myocardial infarction and limb amputations. It is unclear as yet why some patients suffer from isolated thrombocytopenia (HIT), whilst others have HITTS. The aim of the present study was to look for clinical and laboratory features related to the occurrence of HITTS. Patients and methods. We retrospectively analysed the clinical records of 56 patients with proven HIT, as diagnosed on clinical grounds and by in vitro demonstration of immunoglobulin (IgG)/IgM against the PF4/heparin complex. Thirty‐four patients (61%) had HITTS (19 venous thrombosis, seven arterial thrombosis, five arterial and venous thrombosis, two skin necrosis, one diffuse intravascular coagulation), whereas 22 had uncomplicated HIT. Amongst HITTS patients, two had limb amputation, five had recurrent thrombosis and seven died. Amongst HIT patients three died from causes unrelated to HIT. Results. No significant difference in sex, age, previous exposure to heparin, UFH route of administration or dose, duration of therapy, time of onset of thrombocytopenia and platelet count recovery, nor antiheparin/PF4 antibodies subtype (IgG or IgM) was detected when comparing HIT and HITTS. In contrast, in the HITTS group a higher prevalence of orthopaedic surgery (15 of 34 vs. 2/22; P=0.01), a significantly lower platelet count nadir (43 ± 32 vs. 75 ± 63 × 109/L; P=0.01) and a significantly higher titre of antiheparin/PF4 antibodies, expressed as optical density of enzyme‐linked immunosorbent assay (ELISA); (1989 ± 1024 vs. 1277 ± 858; P=0.009), were observed in comparison with the HIT group. Amongst HITTS patients, the prevalence of venous thrombosis was significantly higher in orthopaedic patients and in those being treated for venous thromboembolism (18/24 vs. 1/9 patients, χ2 8.4, P=0.004), whilst arterial thrombosis (ART) occurred more often in heparin treatment for arterial disease (3/4 vs. 4/29 patients, χ2 4.6, P=0.03). Conclusions. Orthopaedic surgery, the severity of thrombocytopenia and high antiheparin/PF4 antibodies titre are adverse prognostic or concurrent factors in the development of HITTS.
Sudden cardiac death in 15–35‐year olds in Sweden during 1992–99
Authors: Wisten A. , Forsberg H. , Krantz P. , Messner T. 
Published: March 2003

Abstract.  Wisten A, Forsberg H, Krantz P, Messner T (Sunderby Hospital, Luleå; National Board of Forensic Medicine, Lund; Kiruna District Hospital, Kiruna; and Umeå University Hospital, Umeå; Sweden). Sudden cardiac death in persons 15–35‐year old in Sweden, 1992–99. J Intern Med 2002; 252: 529–536.Objectives.  To study the incidence, pathogenesis and symptoms preceding sudden cardiovascular death amongst 15–35‐year olds without substance abuse in Sweden during 1992–99.Design.  This was a register study of a national database of forensic medicine, Rattsbase. Clinical details were obtained from forensic, police and medical records and from interviews with family members.Setting.  The whole nation of Sweden.Subjects.  Individuals having suffered a sudden cardiac death.Results.  We found 181 cases of sudden cardiovascular death in a nationwide database, Rattsbase, in 15–35‐year olds, of which 132 (73%) were male and 49 (27%) were female, and a rather stable incidence of 0.93 per 100 000 per year. Preceding symptoms were seen in half of the cases. The most common forensic diagnoses were: no structural abnormality (21.0%), coronary atherosclerosis (17.7%), dilated cardiomyopathy (12.2%), hypertrophic cardiomyopathy (10.5%) and myocarditis (10.5%).Conclusion.  Sudden cardiovascular death was uncommon in the young, but the incidence was not decreasing. Postmortem diagnoses were often difficult to establish. There was a high frequency of structurally normal hearts. Because premortal cardiac‐related symptoms are relatively common and treatment methods are developing, we should learn to recognize early symptoms of heart disease. To identify individuals at risk, further studies of preceding symptoms, life‐style factors and electrocardiogram (ECG) changes are needed.
Search for occult secondary osteoporosis: impact of identified possible risk factors on bone mineral density
Authors: Deutschmann H. A. , Weger M. , Weger W. , Kotanko P. , Deutschmann M. J. , Skrabal F. 
Published: March 2003

Abstract. Deutschmann HA, Weger M, Weger W, Kotanko P, Deutschmann MJ, Skrabal F (Krankenhaus der Barmherzigen Brüder, Marschallgasse, Teaching Hospital of the Karl‐Franzens University Graz, Austria). Search for occult secondary osteoporosis: impact of identified possible risk factors on bone mineral density. J Intern Med 2002; 252: 389–397.Objectives. To determine whether the use of more elaborate diagnostic tests can identify possible risk factors for secondary osteoporosis and to evaluate the impact of these possible risk factors on the severity of bone disease in the study population.Design. Cross‐sectional study.Setting and participants.  We have investigated 377 subjects (285 females, 92 males) with osteoporosis (T‐score less than −2.5 in dual energy X‐ray absorption) or nontraumatic lumbar vertebral fractures; these patients were referred to our hospital, a secondary care centre, for evaluation and treatment of osteoporosis.Results. Osteoporosis without attributable risk factor was diagnosed in 106 women (37%) and 30 men (33%). In 241 patients (179 women, 62 men) one or more possible risk factors for osteoporosis (in this paper also called subclinical disease) were revealed. The most common were lactose malabsorption, disturbed exocrine pancreatic function and renal tubular disturbances, including renal hypercalciuria, incomplete renal tubular acidosis and mild phosphate diabetes. The number of possible risk factors in the individual patient was significantly related to the severity of osteoporosis as assessed by Z‐scores (Spearman correlation r = −0.43, P < 0.001, n = 172 for females; r = −0.28, P < 0.05, n = 65 for males).Conclusions. All the identified subclinical diseases would have remained undetected if the currently accepted guidelines for the investigation of patients with osteoporosis were applied. The statistically significant correlation between the number of identified possible risk factors and the severity of bone disease in the individual patient strongly suggests the pathogenetic significance of the identified subclinical diseases. It is yet to be shown, whether specific treatment of these subclinical diseases yields additional improvement of bone mass as compared with standard treatment of osteoporosis.
Telemedicine used for remote prehospital diagnosing in patients suspected of acute myocardial infarction
Authors: Terkelsen C. J. , Nørgaard B. L. , Lassen J. F. , Gerdes J. C. , Ankersen J. P. , Rømer F. , Nielsen T. T. , Andersen H. R. 
Published: March 2003

Abstract. Terkelsen CJ, Nørgaard BL, Lassen JF, Gerdes JC, Ankersen JP, Rømer F, Nielsen TT, Andersen HR (Silkeborg Central Hospital, Silkeborg; Skejby University Hospital, Aarhus N; and Falck, Silkeborg; Denmark). Telemedicine used for remote prehospital diagnosing in patients suspected of acute myocardial infarction. J Intern Med 2002; 252: 412–420.Introduction.  In patients with acute myocardial infarction (AMI), considerable time elapses from symptom onset until initiation of thrombolytic therapy or primary percutaneous coronary intervention. Prehospital diagnosing can reduce time delays, and remote diagnosing using telemedicine may be appropriate in areas and countries where ambulances are not staffed with physicians.Objectives.  To evaluate whether it was technically feasible for physicians at a remote university hospital to diagnose ST‐segment‐elevation‐AMI (AMISTelev) in patients suspected of AMI, who were transported by ambulances to a local hospital. To determine associated prehospital delays and in‐hospital treatment delays.Methods.  Patients carried in telemetry equipped ambulances had 12‐lead electrocardiograms (ECGs) acquired as soon as possible. En route to the local hospital the ECGs were transmitted to a remote university hospital, by use of the GSM‐system. The physician on call at the university hospital interviewed the patients, who were provided with cellular phone headsets, and alerted the local hospital if signs of AMISTelev, bundle‐branch‐block‐AMI or malignant arrhythmia were detected. Patients transported by traditional ambulances were included in a prospective control group.Results.  In 214 (86%) of 250 patients prehospital diagnosing was successful. Geographically related transmission problems were the primary reason for failure. Ninety‐eight per cent of transmitted electrocardiograms and obtained history takings were technically acceptable for diagnostic purposes. Door‐to‐needle times were shorter amongst patients with AMISTelev who were subjected to prehospital diagnosing (n = 13) as compared with patients transported by traditional ambulances (n = 14) (38 vs. 81 min) (P = 0.004).Conclusions.  It was technically feasible to use telemedicine for remote prehospital diagnosing of patients suspected of AMI. Patients subjected to prehospital diagnosing had shorter door‐to‐needle times compared with a prospective control group.
Time‐gated fluorescence lifetime imaging and microvolume spectroscopy using two‐photon excitation
Authors: Sytsma  , Vroom  , De Grauw  , Gerritsen  
Published: March 2003

A scanning microscope utilizing two‐photon excitation in combination with fluorescence lifetime contrast is presented. The microscope makes use of a tunable femtosecond titanium:sapphire laser enabling the two‐photon excitation of a broad range of fluorescent molecules, including UV probes. Importantly, the penetration depth of the two‐photon exciting (infra)red light is substantially greater than for the corresponding single‐photon wavelength while photobleaching is significantly reduced.The time structure of the Ti:Sa laser can be employed in a straightforward way for the realization of fluorescence lifetime imaging. The fluorescence lifetime is sensitive to the local environment of the fluorescent molecule. This behaviour can be used for example to quantify concentrations of ions, such as pH and Ca2+, or pO2 and pCO2. In the set‐up presented here the fluorescence lifetime imaging is accomplished by time‐gated single photon counting.The performance and optical properties of the microscope are investigated by a number of test measurements on fluorescent test beads. Point‐spread functions calculated from measurements on 230‐nm beads using an iterative restoration procedure compare well with theoretical expectations.Lifetime imaging experiments on a test target containing two different types of test bead in a fluorescent buffer all with different lifetimes (2.15 ns, 2.56 ns and 3.34 ns) show excellent quantitative agreement with reference values obtained from time correlated single photon counting measurements. Moreover, the standard deviation in the results can be wholly ascribed to the photon statistics.Measurements of acridine orange stained biofilms are presented as an example of the potential of two‐photon excitation combined with fluorescence lifetime contrast. Fluorescence lifetime and intensity images were recorded over the whole sample depth of 100 μm. Fluorescence intensity imaging is seriously hampered by the rapid decrease of the fluorescence signal as a function of the depth into the sample. Fluorescence lifetime imaging on the other hand is not affected by the decrease of the fluorescence intensity.
Novel MMC microstructure with tailored distribution of the reinforcing phase
Authors: Peng H. X. , Fan Z. , Evans J. R. G. 
Published: March 2003

Saffil short fibre agglomerates with diameters of 0.4 mm to 1 mm have been prepared using a tumbling technique. These were packed and infiltrated with molten 6061 Al alloy to make a metal matrix composite (MMC) with a novel microstructure in which the composite spheres are randomly distributed in the fibre‐free aluminium matrix. In parallel, a commercial preform made of identical Saffil alumina short fibres and having the same fibre volume faction was used to prepare a conventional MMC by the same technique. Microstructural observation indicates that, within the composite spheres, the local volume fraction of fibre decreases from the outer layer to the centre region.The energy absorption during fracture was estimated by using a three point loading test on notched samples and was compared with that for conventional MMCs. Preliminary results suggest that this novel MMC possesses higher energy absorption capability and hence better damage tolerance. The fracture surfaces were examined by scanning electron microscopy in order to inform these experimental results.
High‐resolution electron microscope observation of interface microstructure of a cast Al‐Mg‐Si‐Bi‐Pb(6262)/Al2O3p composite
Authors: Zhou Z. , Fan Z. , Peng H. X. , Li D. X. 
Published: March 2003

High‐resolution electron microscopy was employed to characterize the interface structure of a cast Al‐Mg‐Si‐Bi‐Pb aluminium(6262)‐based composite reinforced by α alumina particles with a trace of β alumina in order to investigate the behaviour of alloying elements in cast composites. Except for a few primary Mg2Si particles, few reaction products were detected at the interface of Al/α‐Al2O3 due to the unfavourable reaction kinetics during the squeeze‐casting process. The Mg2Si particle has an orientation relationship with α‐Al2O3 of [011]Mg2Si//[1210]α‐Al2O3 (111)Mg2Si//(0006)α‐Al2O3. A significant amount of MgAl2O4 was found on the surface of the β‐Al2O3 particles, which is in contrast to the small degree of reaction found on α‐Al2O3 particles. MgAl2O4 and β‐Al2O3 particles have the following orientation relationship: [011]MgAl2O4//[1210]β‐Al2O3 (111) MgAl2O4//(0006)β‐Al2O3. The similar crystal structure of β‐Al2O3 to MgAl2O4 favours MgAl2O4 nucleation and growth on the surface of β‐Al2O3. Interfacial energy minimization dominates the atomic structure of the interface with the result that close packed planes and directions in the Al2O3 reinforcement and reaction products are parallel to the interfaces. Bi and Pb were found in the form of metallic nanometre particles between Al2O3 particles, or between the MgAl2O4 and Al2O3 particles, or in the open channels of β‐Al2O3 filled by the Al matrix.
Experimental statistics of near‐field intensity distributions at nanostructured surfaces
Authors: Coello V. , Bozhevolnyi S. I. 
Published: March 2003

Scanning near‐field optical microscopy is a technique in which the resolution is primarily determined by the size of a probe and not by the wavelength of illumination as in classical (far‐field) microscopy. However, the relationship between a sample and its near‐field optical image is usually rather complex. Typical factors responsible, at least partially, for such a complexity are the conditions of illumination and detection, sample characteristics (e.g. roughness and dielectric constant) and optical properties of the probe. Theoretical and experimental works conducted to improve our understanding of the relation between the object and the image have been reported (Greffet & Carminati, 1997). Recently, with the help of a photon scanning tunnelling microscope we have carried out an extensive study of the resultant near‐field intensity distributions due to the elastic (in the plane) scattering of surface plasmon polaritons (SPPs) at metal film surfaces. We have also directly observed (in similar experimental conditions) localized dipolar excitations in silver colloid fractals (Bozhevolnyi et al., 1998). In both cases, the studied phenomena are intimately related to the regime of multiple light scattering, in which the interference effects are rather complicated and therefore a proper interpretation of them was far from being trivial. Thus, even though a certain understanding of many features inherent to the subwavelength light interference phenomena was gained (Bozhevolnyi & Coello, 1998; Bozhevolnyi et al., 1998; Coello & Bozhevolnyi, 1999), it is clear from the outcome of the investigations that more systematic studies in this context are still needed. A different and more powerful approach may be a statistical study of the recorded near‐field intensity distributions. In this work, we report what we believe to be the first results on experimental statistics of near‐field optical images exhibiting localized optical excitations (related to the regime of multiple scattering of light). We investigated optical images obtained with SPPs excited at different light wavelengths and scattered at different film surfaces, and with different polarizations and wavelengths of light scattered by silver colloid fractal structures. We have found significant differences in statistics between near‐field intensity distributions taken at rough and smooth metal film surfaces and fractal structures. Finally, our predictions seem to be in agreement with theoretical studies reported by other authors (Sanchez‐Gil & Garcia‐Ramos, 1998).
Cation segregation in Nb16W18O94 using high angle annular dark field scanning transmission electron microscopy and image processing
Authors: Kirkland A. I. , Saxton W. O. 
Published: March 2003

SummaryWe report the characterization of the complex oxide Nb16W18O94 using high angle annular dark field imaging at 200 kV in a scanning transmission electron microscope. The results of this study suggest that the W and Nb cations are not uniformly distributed among the cation columns projected along [001] but that there is preferential segregation of the heavier species to certain column sites. In order to analyse the experimental data obtained, an image processing methodology has been developed which may also find application in locating specific motifs within a generally distorted image field.
Automated reconstruction of curvilinear fibres from 3D datasets acquired by X‐ray microtomography
Authors: Eberhardt C. N. , Clarke A. R. 
Published: March 2003

SummaryThe characterization of fibrous structures is important in both composites and textiles research for relating to the bulk properties of the material. However, the microscopic nature of the fibres and their high densities make them very difficult to characterize. Many techniques have been developed for the measurement and characterization of fibrous structures but they tend to be restricted to measurements on the sample surface or within physical cross‐sections. X‐ray microtomography can be used to non‐destructively probe the internal structure of a range of fibrous materials, providing large amounts of 3D data. A technique has been developed for tracing fibres within 3D datasets acquired by X‐ray microtomography and this has been applied to a glass fibre reinforced composite and also a non‐woven textile sample. The 3D fibrous structures of both samples were successfully reconstructed and their fibre orientation distributions calculated. This technique enables novel characterizations, such as the through‐thickness variation of fibre orientation in non‐wovens.
Improving the quality of electron backscatter diffraction (EBSD) patterns from nanoparticles
Authors: Small J. A. , Michael J. R. , Bright D. S. 
Published: March 2003

SummaryIn this study, we investigated the relative contributions of atomic number (Z) and density (ρ) to the degradation of the electron backscatter diffraction (EBSD) pattern quality for nanoparticles < 500 nm in diameter. This was accomplished by minimizing the diffuse scattering from the conventional thick mounting substrate through the design of a sample holder that can accommodate particles mounted on thin‐film TEM substrates. With this design, the contributions of incoherently scattered electrons that result in the diffuse background are minimized. Qualitative and quantitative comparisons were made of the EBSD pattern quality obtained from Al2O3particles approximately 200 nm in diameter mounted on both thick‐ and thin‐film C substrates. For the quantitative comparison we developed a ‘quality’ factor for EBSD patterns that is based on the ratio of two Hough transforms derived from a given EBSD pattern image. The calculated quality factor is directly proportional to the signal‐to‐noise ratio for the EBSD pattern. In addition to the comparison of the thick and thin mounting substrates, we also estimated the effects of Z and ρ by comparing the EBSD pattern quality from the Al2O3particles mounted on thin‐film substrates with the quality of patterns obtained from Fe–Co nanoparticles approximately 120 nm in diameter.The results indicate that the increased background generated in EBSD patterns by the electrons escaping through the bottom of the small particles is the dominant reason for the poor EBSD pattern quality from nanoparticles < 500 nm in size. This was supported by the fact that we were able to obtain usable EBSD patterns from Al2O3particles as small as 130 nm using the thin‐film mounting method.
Deconvolution improves colocalization analysis of multiple fluorochromes in 3D confocal data sets more than filtering techniques
Authors: Landmann L. 
Published: March 2003

SummaryBackground and noise impair image quality by affecting resolution and obscuring image detail in the low intensity range. Because background levels in unprocessed confocal images are frequently at about 30% maximum intensity, colocalization analysis, a typical segmentation process, is limited to high intensity signal and prone to noise‐induced, false‐positive events. This makes suppression or removal of background crucial for this kind of image analysis. This paper examines the effects of median filtering and deconvolution, two image‐processing techniques enhancing the signal‐to‐noise ratio (SNR), on the results of colocalization analysis in confocal data sets of biological specimens.The data show that median filtering can improve the SNR by a factor of 2. The technique eliminates noise‐induced colocalization events successfully. However, because filtering recovers voxel values from the local neighbourhood false‐negative (‘dissipation’ of signal intensity below threshold value) as well as false‐positive (‘fusion’ of noise with low intensity signal resulting in above threshold intensities), results can be generated. In addition, filtering involves the convolution of an image with a kernel, a procedure that inherently impairs resolution.Image restoration by deconvolution avoids both of these disadvantages. Such routines calculate a model of the object considering various parameters that impair image formation and are able to suppress background down to very low levels (< 10% maximum intensity, resulting in a SNR improved by a factor 3 as compared to raw images). This makes additional objects in the low intensity but high frequency range available to analysis. In addition, removal of noise and distortions induced by the optical system results in improved resolution, which is of critical importance in cases involving objects of near resolution size. The technique is, however, sensitive to overestimation of the background level. In conclusion, colocalization analysis will be improved by deconvolution more than by filtering. This applies especially to specimens characterized by small object size and/or low intensities.