Speckle-based x-ray phase-contrast and dark-field imaging with a laboratory source.

We report on the observation and application of near-field speckles with a laboratory x-ray source. The detection of speckles is possible thanks to the enhanced brilliance properties of the used liquid-metal-jet source, and opens the way to a range of new applications in laboratory-based coherent x-ray imaging. Here, we use the speckle pattern for multimodal imaging of demonstrator objects. Moreover, we introduce algorithms for phase and dark-field imaging using speckle tracking, and we show that they yield superior results with respect to existing methods.

Comparison of two x-ray phase-contrast imaging methods with a microfocus source.

We present a comparison for high-resolution imaging with a laboratory source between grating-based (GBI) and propagation-based (PBI) x-ray phase-contrast imaging. The comparison is done through simulations and experiments using a liquid-metal-jet x-ray microfocus source. Radiation doses required for detection in projection images are simulated as a function of the diameter of a cylindrical sample. Using monochromatic radiation, simulations show a lower dose requirement for PBI for small object features and a lower dose for GBI for larger object features. Using polychromatic radiation, such as that from a laboratory microfocus source, experiments and simulations show a lower dose requirement for PBI for a large range of feature sizes. Tested on a biological sample, GBI shows higher noise levels than PBI, but its advantage of quantitative refractive index reconstruction for multi-material samples becomes apparent.

Laboratory cryo soft X-ray microscopy.

Lens-based water-window X-ray microscopy allows two- and three-dimensional (2D and 3D) imaging of intact unstained cells in their near-native state with unprecedented contrast and resolution. Cryofixation is essential to avoid radiation damage to the sample. Present cryo X-ray microscopes rely on synchrotron radiation sources, thereby limiting the accessibility for a wider community of biologists. In the present paper we demonstrate water-window cryo X-ray microscopy with a laboratory-source-based arrangement. The microscope relies on a λ=2.48-nm liquid-jet high-brightness laser-plasma source, normal-incidence multilayer condenser optics, 30-nm zone-plate optics, and a cryo sample chamber. We demonstrate 2D imaging of test patterns, and intact unstained yeast, protozoan parasites and mammalian cells. Overview 3D information is obtained by stereo imaging while complete 3D microscopy is provided by full tomographic reconstruction. The laboratory microscope image quality approaches that of the synchrotron microscopes, but with longer exposure times. The experimental image quality is analyzed from a numerical wave-propagation model of the imaging system and a path to reach synchrotron-like exposure times in laboratory microscopy is outlined.

Compact x-ray microscope for the water window based on a high brightness laser plasma source.

We present a laser plasma based x-ray microscope for the water window employing a high-average power laser system for plasma generation. At 90 W laser power a brightness of 7.4 x 10(11) photons/(s x sr x µm(2)) was measured for the nitrogen Lyα line emission at 2.478 nm. Using a multilayer condenser mirror with 0.3 % reflectivity 10(6) photons/(µm(2) x s) were obtained in the object plane. Microscopy performed at a laser power of 60 W resolves 40 nm lines with an exposure time of 60 s. The exposure time can be further reduced to 20 s by the use of new multilayer condenser optics and operating the laser at its full power of 130 W.

High average brightness water window source for short-exposure cryomicroscopy.

Laboratory water window cryomicroscopy has recently demonstrated similar image quality as synchrotron-based microscopy but still with much longer exposure times, prohibiting the spread to a wider scientific community. Here we demonstrate high-resolution laboratory water window imaging of cryofrozen cells with 10 s range exposure times. The major improvement is the operation of a λ=2.48 nm, 2 kHz liquid nitrogen jet laser plasma source with high spatial and temporal stability at high average brightness >1.5×10(12) ph/(s×sr×µm(2)×line), i.e., close to that of early synchrotrons. Thus, this source enables not only biological x-ray microscopy in the home laboratory but potentially other applications previously only accessible at synchrotron facilities.

Stability investigation of a cryo soft x-ray microscope by fiber interferometry.

We present a stability investigation of the Stockholm laboratory cryo soft x-ray microscope. The microscope operates at a wavelength of 2.48 nm and can image biological samples at liquid-nitrogen temperatures in order to mitigate radiation damage. We measured the stability of the two most critical components, sample holder and optics holder, in vacuo and at cryo temperatures at both short and long time scales with a fiber interferometer. Results revealed vibrations in the kHz range, originating mainly from a turbo pump, as well as long term drifts in connection with temperature fluctuations. With improvements in the microscope, earlier stability issues vanished and close-to diffraction-limited imaging could be achieved. Moreover, our investigation shows that fiber interferometers are a powerful tool in order to investigate position-sensitive setups at the nanometer level.

Mass of vesta.

The asteroid 197 (Arete) approaches asteroid 4 (Vesta) within 0.04 astronomical unit once every 18 years. It may therefore be possible to determine the mass of Vesta from observations of Arete. From 72 observations a value of (1.20 +/- 0.08) x 10(-10) solar mass was derived, the indicated uncertainty being a probable error.

A 9 keV electron-impact liquid-gallium-jet x-ray source.

We demonstrate a high-brightness compact 9 keV electron-impact microfocus x-ray source based on a liquid-gallium-jet anode. A approximately 30 W, 50 kV electron gun is focused onto the approximately 20 ms, 30 mum diameter liquid-gallium-jet anode to produce an approximately 10 microm full width at half maximum x-ray spot. The peak spectral brightness is >2 x 10(10) photons(s mm(2) mrad(2)x0.1% BW). Calculation and experiments show potential for increasing this brightness by approximately three orders of magnitude, making the source suitable for laboratory-scale x-ray crystallography and hard x-ray microscopy.

Proliferation and viability of adherent cells manipulated by standing-wave ultrasound in a microfluidic chip.

Ultrasonic-standing-wave (USW) technology has potential to become a standard method for gentle and contactless cell handling in microfluidic chips. We investigate the viability of adherent cells exposed to USWs by studying the proliferation rate of recultured cells following ultrasonic trapping and aggregation of low cell numbers in a microfluidic chip. The cells form 2-D aggregates inside the chip and the aggregates are held against a continuous flow of cell culture medium perpendicular to the propagation direction of the standing wave. No deviations in the doubling time from expected values (24 to 48 h) were observed for COS-7 cells held in the trap at acoustic pressure amplitudes up to 0.85 MPa and for times ranging between 30 and 75 min. Thus, the results demonstrate the potential of ultrasonic standing waves as a tool for gentle manipulation of low cell numbers in microfluidic systems.

Nerve regeneration using tubular scaffolds from biodegradable polyurethane.

INTRODUCTION: In severe nerve lesion, nerve defects and in brachial plexus reconstruction, autologous nerve grafting is the golden standard. Although, nerve grafting technique is the best available approach a major disadvantages exists: there is a limited source of autologous nerve grafts. This study presents data on the use of tubular scaffolds with uniaxial pore orientation from experimental biodegradable polyurethanes coated with fibrin sealant to regenerate a 8 mm resected segment of rat sciatic nerve. METHODS: Tubular scaffolds: prepared by extrusion of the polymer solution in DMF into water coagulation bath. The polymer used for the preparation of tubular scaffolds was a biodegradable polyurethane based on hexamethylene diisocyanate, poly(epsilon-caprolactone) and dianhydro-D-sorbitol. EXPERIMENTAL MODEL: Eighteen Sprague Dawley rats underwent mid-thigh sciatic nerve transection and were randomly assigned to two experimental groups with immediate repair: (1) tubular scaffold, (2) 180 degrees rotated sciatic nerve segment (control). Serial functional measurements (toe spread test, placing tests) were performed weekly from 3rd to 12th week after nerve repair. On week 12, electrophysiological assessment was performed. Sciatic nerve and scaffold/nerve grafts were harvested for histomorphometric analysis. Collagenic connective tissue, Schwann cells and axons were evaluated in the proximal nerve stump, the scaffold/nerve graft and the distal nerve stump. The implants have uniaxially-oriented pore structure with a pore size in the range of 2 micorm (the pore wall) and 75 x 700 microm (elongated pores in the implant lumen). The skin of the tubular implants was nonporous. Animals which underwent repair with tubular scaffolds of biodegradable polyurethanes coated with diluted fibrin sealant had no significant functional differences compared with the nerve graft group. Control group resulted in a trend-wise better electrophysiological recovery but did not show statistically significant differences. There was a higher level of collagenic connective tissue within the scaffold and within the distal nerve stump. Schwann cells migrated into the polyurethane scaffold. There was no statistical difference to the nerve graft group although Schwann cell counts were lower especially within the middle of the polyurethane scaffold. Axon counts showed a trend-wise decrease within the scaffold. CONCLUSION: These results suggest that biodegradable polyurethane tubular scaffolds coated with diluted fibrin sealant support peripheral nerve regeneration in a standard gap model in the rat up to 3 months. Three months after surgery no sign of degradation could be seen.

Ultrasonic enhancement of bead-based bioaffinity assays.

Ultrasonic radiation forces can be used for non-intrusive manipulation and concentration of suspended micrometer-sized particles. For bioanalytical purposes, standing-wave ultrasound has long been used for rapid immuno-agglutination of functionalized latex beads. More recently, detection methods based on laser-scanning fluorometry and single-step homogeneous bead-based assays show promise for fast, easy and sensitive biochemical analysis. If such methods are combined with ultrasonic enhancement, detection limits in the femtomolar region are feasible. In this paper, we review the development of standing-wave ultrasonic manipulation for bioanalysis, with special emphasis on miniaturization and ultrasensitive bead-based immunoassays.

Ultrasonic standing wave manipulation technology integrated into a dielectrophoretic chip.

Several cell-based biological applications in microfluidic systems require simultaneous high-throughput and individual handling of cells or other bioparticles. Available chip-based tools for contactless manipulation are designed for either high-precision handling of individual particles, or high-throughput handling of ensembles of particles. In order to simultaneously perform both, we have combined two manipulation technologies based on ultrasonic standing waves (USWs) and dielectrophoresis (DEP) in a microfluidic chip. The principle is based on the competition between long-range ultrasonic forces, short-range dielectrophoretic forces and viscous drag forces from the fluid flow. The ultrasound is coupled into the microchannel resonator by an external transducer with a refractive element placed on top of the chip, thereby allowing transmission light microscopy to continuously monitor the biological process. The DEP manipulation is generated by an electric field between co-planar microelectrodes placed on the bottom surface of the fluid channel. We demonstrate flexible and gentle elementary manipulation functions by the use of USWs and linear or curved DEP deflector elements that can be used in high-throughput biotechnology applications of individual cells.

Segway® related injuries in Vienna: report from the Lorenz Böhler Trauma Centre.

INTRODUCTION: The Segway® vehicle facilitates a new way of eco-friendly mobility and is currently used all over the world. In the last years, the use of the Segway® transporters for sightseeing tours in Vienna has increased distinctly, resulting in a growing number of Segway® related injuries and subsequent admissions of these patients to the Lorenz Böhler Trauma Centre in Vienna, Austria. METHODS: A retrospective analysis of clinical records in the electronic data system of the LBTC in Vienna, Austria, was performed to identify Segway® transporter related injuries between January 2010 and December 2012. RESULTS: Eighty-six patients represented the study cohort. The median age was 38 years (range 14-80 years) with a majority of male patients. Most common injuries were contusions (24, 6 %, n = 44) and fractures (23, 5 %, n = 42). The most frequent injury was a fracture of the radial head in 15, 1 % of all patients. 13 (15, 1 %) of 86 patients required admission and seven (8, 1 %) of these 13 patients had surgical treatment. CONCLUSION: This case series presents severe injuries related to the use of a Segway® transporter. As a consequence, it has to be ensured that public tour operators need to provide sufficient safety instructions and equipment for people who are unfamiliar with riding a Segway® .

Bone mass after treatment for acute lymphoblastic leukemia in childhood.

PURPOSE: To study bone mass after childhood acute lymphoblastic leukemia (ALL) and determine if reduced bone mass is related to previous therapy or endocrine status at follow-up. PATIENTS AND METHODS: We studied 95 survivors of childhood ALL who were in first remission a median of 11 years (range, 3 to 23 years) after diagnosis and who had never been irradiated outside a cranial field. The bone mass was measured by dual-energy x-ray absorptiometry. The results were compared with data on 396 local controls. RESULTS: Adjusted for sex and age, the mean whole-body bone mineral content (BMC) and bone mineral areal density (BMDA) were both significantly reduced (0.4 SDs less than the predicted mean value). This was mainly caused by reduced bone mass in the 33 participants who were aged 19 years or older at follow-up. In these young adults, the mean height for age, bone area for height, and BMC for bone area were all significantly reduced. This indicated that the reduced whole-body bone mass was caused by both reduced bone size and reduced size-adjusted bone mass. Reduced bone size was related to previous cranial irradiation. Reduced size-adjusted bone mass was not significantly related to age at diagnosis or at follow-up, length of follow-up, cranial irradiation, cumulative dose of methotrexate or corticosteroids, or endocrine status at follow-up. CONCLUSION: The whole-body bone mass was reduced 11 years after diagnosis of childhood ALL. If these abnormalities remain, survivors of childhood ALL will have an increased risk for osteoporotic fractures later in life.

Risk of subsequent malignant neoplasms among 1,641 Hodgkin's disease patients diagnosed in childhood and adolescence: a population-based cohort study in the five Nordic countries. Association of the Nordic Cancer Registries and the Nordic Society of Pediatric Hematology and Oncology.

PURPOSE: To assess the risk of subsequent malignant neoplasms among Hodgkin's disease patients diagnosed before 20 years of age in the five Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden). PATIENTS AND METHODS: There were 1,641 Hodgkin's disease patients identified through the national cancer registries since the 1940s or 1950s. The patients were monitored for 17,000 person-years until the end of 1991. Expected figures were derived from the age-specific incidence rates in each country and standardized incidence ratios (SIR) were calculated. RESULTS: A total of 62 subsequent neoplasms were diagnosed (SIR, 7.7; 95% confidence interval [CI], 5.9 to 9.9). The overall cumulative risk of subsequent neoplasms was 1.9% at the 10-year follow-up point, 6.9% at 20 years, and 18% at 30 years. There were 26 subsequent neoplasms among males (SIR, 6.5; 95% CI, 4.3 to 9.6) and 36 among females (SIR, 8.9; 95% CI, 6.2 to 12), of which 16 were breast cancers (SIR, 17; 95% CI, 9.9 to 28). High risks were seen for thyroid cancer (SIR, 33; 95% CI, 15 to 62), for secondary leukemia (SIR, 17; 95% CI, 6.9 to 35), and for non-Hodgkin's lymphoma (SIR, 15; 95% CI, 4.9 to 35). The relative risk increased from 3.3 (95% CI, 1.2 to 7.1) for Hodgkin's disease patients diagnosed in the 1940s and 1950s to 15 (95% CI, 7.4 to 27) in the 1980s. The highest risk of secondary leukemia (SIR, 68; 95% CI, 18 to 174) was seen among those diagnosed with Hodgkin's disease in the 1980s. CONCLUSION: Patients who survive Hodgkin's disease at a young age are at very high relative risk of subsequent malignant neoplasms throughout their lives. In particular, the high relative risk of breast cancer following Hodgkin's disease in the teenage years calls for enhanced activity for early diagnosis.

Relationship between cumulative anthracycline dose and late cardiotoxicity in childhood acute lymphoblastic leukemia.

PURPOSE: Late anthrocycline cardiotoxicity after treatment for childhood cancer is common and often progressive. A safe anthracycline dose that will not result in late cardiac abnormalities has not been established due to the limited dose ranges used in existing studies. PATIENTS AND METHODS: To determine the relationship between cumulative anthracycline dose and late cardiotoxicity, we performed echocardiograms on 189 survivors of childhood acute lymphoblastic leukemia a median of 8.1 years (range, 2.0 to 23.4) after completion of anthracycline therapy. Patients were treated according to protocols that used widely varying cumulative anthracycline doses, but comparable nonanthracycline chemotherapy. Patients were divided into four groups based on the city of treatment and cumulative anthracycline dose: Copenhagen, 0 to 23 mg/m2 (n = 32); Boston, 45 mg/m2 (n = 17); Copenhagen, 73 to 301 mg/m2 (n = 53); and Boston, 244 to 550 mg/m2 (n = 87). Left ventricular dimension and fractional shortening were adjusted for sex and age or body-surface area through use of a control population (n = 296), and then compared among the four groups. RESULTS: Mean left ventricular dimension was significantly increased in the high-dose Boston group (observed:predicted value, 4.57 cm:4.45 cm; P = .002) and significantly higher than in the two Copenhagen groups. In the three lower-dose groups, there was no significant increase in mean left ventricular dimension, and the groups were not significantly different from each other. Similarly, the mean left ventricular fractional shortening was significantly depressed in the high-dose Boston group (observed:predicted value, 29.0%:33.8%; P = .0001) and significantly lower than in the three lower-dose groups. CONCLUSION: Depressed left ventricular fractional shortening and left ventricular dilatation were uncommon years after treatment of childhood leukemia when cumulative anthracycline doses were < or = 300 mg/m2.

Degree of fatness after treatment for acute lymphoblastic leukemia in childhood.

Excessive fatness is considered a frequent late complication of treatment for childhood acute lymphoblastic leukemia. Most previous studies, however, were based on body mass index (BMI) rather than more direct fat mass measurements. We studied 95 survivors of childhood acute lymphoblastic leukemia a median of 11 yr (range, 3-23 yr) after diagnosis. BMI values at diagnosis, at cessation of therapy, yearly thereafter for up to 10 yr, and at follow-up were compared with French reference values. Whole body percent fat was measured at follow-up by dual energy x-ray absorptiometry and compared with data from 463 local controls. Adjusted for sex and age, the mean BMI increased significantly during therapy and remained largely unchanged thereafter. At follow-up, BMI did not differ significantly between patients and local controls. On the other hand, the whole body percent fat was significantly increased (mean observed/predicted value, 21.8/19.0%; P < 0.0002). Twenty-five patients (26%) had a percent fat above the 90th percentile of the reference values, which indicates excessive fatness. Adjusted for sex and age, a higher percent fat was related to cranial irradiation or GH insufficiency, but not to sex, the cumulative doses of anthracyclines or corticosteroids, or the type of corticosteroid used. BMI was a poor measure of body fatness.

Gonadal status in male survivors following childhood brain tumors.

The effect of radiotherapy (RT) and chemotherapy (CT) on gonadal function was assessed in males treated for a childhood brain tumor not directly involving the hypothalamus/pituitary (HP) axis in a population-based study with a long follow-up time. All males <15 yr at the time of diagnosis (median: 9.0 yr, range: 0.8 to 14.9 yr) and diagnosed from January 1970 through February 1997 in the eastern part of Denmark and [gte]18 yr at the time of follow-up (median: 25.8 yr, range:18.5 to 39.3 yr) were included. Thirty males fulfilled the criteria. The median age at time of RT was 9.0 yr (range: 0.8 to 14.9 yr) and the median length of follow-up was 18 yr (range: 2.0 to 28.0 yr). The biological effective dose of RT was determined to the HP region and to the spine and expressed in gray because the biological effective dose gives a means of expressing the biological effect on normal tissue of different dosage schedules in a uniform way. Levels of serum FSH, luteinizing hormone (LH), sexual hormone-binding globulin, testosterone, and inhibin B were measured and compared with healthy age-matched male controls (n = 347), and the patients had a GnRH stimulation test performed with determination of peak FSH and LH. Patients treated with RT + CT (n = 13), compared with patients treated with RT only (n = 17), had significantly higher median peak FSH (8.33 vs. 3.79 IU/L, P = 0.03) and median peak LH (20.0 vs. 12.8 IU/L, P = 0.03), and significantly lower median inhibin B (86.0 vs. 270 pg/ml, P = 0.03), and median inhibin B/FSH ratio (12.8 vs. 107.9, P = 0.04), which indicates gonadal damage. Inhibin B and inhibin B/FSH ratio were also significantly lower in the RT + CT group, compared with controls (median: 86.0 vs. 215 pg/ml, P = 0.02), (median:12.8 vs. 67; P = 0.01), respectively. We found a significantly inverse correlation between basal FSH and inhibin B and FSH and total testicular volume (r(s) = -0.83; P < 0.0001), (r(s) = -0.67; P < 0.0001), respectively, and a significant correlation between inhibin B and total testicular volume (r(s) = 0.63; P < 0.0001). Stepwise backward multiple linear regression analysis showed the best-fit model to predict inhibin B levels included total testicular volume (P = 0.002) and CT (P = 0.09). Median basal LH in the RT-only group was significantly lower, compared with controls (3.44 vs. 2.45 IU/L; P = 0.0001) indicating secondary hypogonadism, and in both the RT + CT group and the RT-only group, levels of testosterone were significantly lower, compared with our reference population (12.8 vs. 21.9 nmol/L; P = 0.001, and 14.7 vs. 21.9 nmol/L; P = 0.0003), respectively. In conclusion these data suggest that cranial irradiation for a childhood brain tumor may affect the HP axis, and adjuvant CT can reduce inhibin B indicating primary gonadal damage. Thus, such patients may have normal or even low levels of FSH despite damage to the seminiferous epithelium, and because the fertility status by a semen analysis for psychological reasons can be difficult to obtain in this group of patients, we suggest inhibin B as the most useful direct serum marker of spermatogenesis in the follow-up of individuals who have received both cranial irradiation and gonadotoxic chemotherapy. However, because the number of patients with RT + CT and RT only are small, these data must be confirmed in further studies.

Cancer in the offspring of parents with lung cancer.

Despite several studies on the role of passive smoking in the development of childhood cancer, particularly leukaemia, lymphomas and brain cancer, no definitive answer has yet been provided. The aim of the cohort study reported here was to analyse the incidence of cancer in the offspring of young lung cancer patients on the basis of the assumption that all of the offspring were exposed passively to smoke. The files of the Danish Cancer Registry provided 3348 cases of lung cancer patients born after 1935, and their offspring (n = 6417) were identified through the Danish Population Register. The files of the offspring were then linked with the files of the Danish Cancer Registry and the numbers of cancers observed in the offspring were compared with those expected from national age-specific and calendar-time-specific rates. A total of 135,333 person-years was the basis for analysis. Twenty-six cancers were observed, with 30.3 expected, yielding a standardised incidence ratio (SIR) of 0.9 (90% confidence interval (CI), 0.6-1.2). There was no excess of brain tumours, leukaemias or lymphomas. Stratification for sex of the lung cancer patients revealed a non-significantly increased risk for both non-Hodgkin's lymphoma (three cases; SIR = 3.4; 90% CI: 0.9-8.7) and Hodgkin's disease (three cases; SIR = 2.6; 90% CI: 0.7-6.6) in the offspring of female lung cancer patients. These results suggest that there is little evidence of an excess cancer risk in childhood, whether due to passive smoking or to as yet unidentified genetic factors, among the offspring of people who develop lung cancer. However, the results are limited by the fact that exposure was only assessed indirectly, with no measurement of actual cigarette consumption made.

Incidence of childhood cancer in Denmark 1943-1984.

A population-based study was carried out on 5790 tumours in children (aged 0-14 years) diagnosed in the period 1943-1984 in Denmark. Cases were identified from the files of the high-quality National Cancer Registry in which codes for tumours were based solely on topography until the end of 1977. To achieve a uniform data set following the outlines of the International Classification of Diseases for Oncology (ICD-O) coding system used by the Cancer Registry today, all cases of childhood cancer diagnosed prior to 1978 were re-evaluated, and an ICD-O code was applied. Tumours were aggregated into diagnostic groups suitable for analysis and presentation using an internationally agreed scheme, which was designed by the Manchester Children's Tumour Registry and modified recently by the International Agency for Research on Cancer. The average incidence rates for all histological types of childhood cancer combined were 137 per million boys and 111 per million girls, which are close to those reported from the USA but higher than most of the overall figures reported from Europe. The proportions of specific tumours were similar to those observed in other industrialized countries. The well known excess of cancer cases among boys compared to girls was due mainly to the occurrence of 90% more lymphomas, 30% more leukaemias and 15% more tumours of the central nervous system (CNS) among boys. Although significant increases were seen in the subgroups of CNS neoplasms and neuroblastomas (both sexes) and of lymphomas (boys only), no overall increase in childhood cancer was observed during the 42-year period of registration. While the increase in the incidence of CNS tumours was explained at least partly by better cancer surveillance, no interpretation can be offered for the increases seen for neuroblastomas and lymphomas. Our descriptive data suggest that environmental exposures do not play any significant role in the aetiology of the majority of childhood cancers.