Low-temperature nanoscale heat transport in a gadolinium iron garnet heterostructure probed by ultrafast x-ray diffraction.

Time-resolved x-ray diffraction has been used to measure the low-temperature thermal transport properties of a Pt/Gd3Fe5O12//Gd3Ga5O12 metal/oxide heterostructure relevant to applications in spin caloritronics. A pulsed femtosecond optical signal produces a rapid temperature rise in the Pt layer, followed by heat transport into the Gd3Fe5O12 (GdIG) thin film and the Gd3Ga5O12 (GGG) substrate. The time dependence of x-ray diffraction from the GdIG layer was tracked using an accelerator-based femtosecond x-ray source. The ultrafast diffraction measurements probed the intensity of the GdIG (1 -1 2) x-ray reflection in a grazing-incidence x-ray diffraction geometry. The comparison of the variation of the diffracted x-ray intensity with a model including heat transport and the temperature dependence of the GdIG lattice parameter allows the thermal conductance of the Pt/GdIG and GdIG//GGG interfaces to be determined. Complementary synchrotron x-ray diffraction studies of the low-temperature thermal expansion properties of the GdIG layer provide a precise calibration of the temperature dependence of the GdIG lattice parameter. The interfacial thermal conductance of the Pt/GdIG and GdIG//GGG interfaces determined from the time-resolved diffraction study is of the same order of magnitude as previous reports for metal/oxide and epitaxial dielectric interfaces. The thermal parameters of the Pt/GdIG//GGG heterostructure will aid in the design and implementation of thermal transport devices and nanostructures.

Binding of the human antioxidation protein α1-microglobulin (A1M) to heparin and heparan sulfate. Mapping of binding site, molecular and functional characterization, and co-localization in vivo and in vitro.

Heparin and heparan sulfate (HS) are linear sulfated disaccharide polymers. Heparin is found mainly in mast cells, while heparan sulfate is found in connective tissue, extracellular matrix and on cell membranes in most tissues. α1-microglobulin (A1M) is a ubiquitous protein with thiol-dependent antioxidant properties, protecting cells and matrix against oxidative damage due to its reductase activities and radical- and heme-binding properties. In this work, it was shown that A1M binds to heparin and HS and can be purified from human plasma by heparin affinity chromatography and size exclusion chromatography. The binding strength is inversely dependent of salt concentration and proportional to the degree of sulfation of heparin and HS. Potential heparin binding sites, located on the outside of the barrel-shaped A1M molecule, were determined using hydrogen deuterium exchange mass spectrometry (HDX-MS). Immunostaining of endothelial cells revealed pericellular co-localization of A1M and HS and the staining of A1M was almost completely abolished after treatment with heparinase. A1M and HS were also found to be co-localized in vivo in the lungs, aorta, kidneys and skin of mice. The redox-active thiol group of A1M was unaffected by the binding to HS, and the cell protection and heme-binding abilities of A1M were slightly affected. The discovery of the binding of A1M to heparin and HS provides new insights into the biological role of A1M and represents the basis for a novel method for purification of A1M from plasma.

High-resolution macromolecular crystallography at the FemtoMAX beamline with time-over-threshold photon detection.

Protein dynamics contribute to protein function on different time scales. Ultrafast X-ray diffraction snapshots can visualize the location and amplitude of atom displacements after perturbation. Since amplitudes of ultrafast motions are small, high-quality X-ray diffraction data is necessary for detection. Diffraction from bovine trypsin crystals using single femtosecond X-ray pulses was recorded at FemtoMAX, which is a versatile beamline of the MAX IV synchrotron. The time-over-threshold detection made it possible that single photons are distinguishable even under short-pulse low-repetition-rate conditions. The diffraction data quality from FemtoMAX beamline enables atomic resolution investigation of protein structures. This evaluation is based on the shape of the Wilson plot, cumulative intensity distribution compared with theoretical distribution, I/σ, Rmerge/Rmeas and CC1/2 statistics versus resolution. The FemtoMAX beamline provides an interesting alternative to X-ray free-electron lasers when studying reversible processes in protein crystals.

Femtosecond x-ray diffraction reveals a liquid-liquid phase transition in phase-change materials.

In phase-change memory devices, a material is cycled between glassy and crystalline states. The highly temperature-dependent kinetics of its crystallization process enables application in memory technology, but the transition has not been resolved on an atomic scale. Using femtosecond x-ray diffraction and ab initio computer simulations, we determined the time-dependent pair-correlation function of phase-change materials throughout the melt-quenching and crystallization process. We found a liquid-liquid phase transition in the phase-change materials Ag4In3Sb67Te26 and Ge15Sb85 at 660 and 610 kelvin, respectively. The transition is predominantly caused by the onset of Peierls distortions, the amplitude of which correlates with an increase of the apparent activation energy of diffusivity. This reveals a relationship between atomic structure and kinetics, enabling a systematic optimization of the memory-switching kinetics.

FemtoMAX - an X-ray beamline for structural dynamics at the short-pulse facility of MAX IV.

The FemtoMAX beamline facilitates studies of the structural dynamics of materials. Such studies are of fundamental importance for key scientific problems related to programming materials using light, enabling new storage media and new manufacturing techniques, obtaining sustainable energy by mimicking photosynthesis, and gleaning insights into chemical and biological functional dynamics. The FemtoMAX beamline utilizes the MAX IV linear accelerator as an electron source. The photon bursts have a pulse length of 100 fs, which is on the timescale of molecular vibrations, and have wavelengths matching interatomic distances (Å). The uniqueness of the beamline has called for special beamline components. This paper presents the beamline design including ultrasensitive X-ray beam-position monitors based on thin Ce:YAG screens, efficient harmonic separators and novel timing tools.

Initiation of Levodopa-Carbidopa Intestinal Gel Infusion Using Telemedicine (Video Communication System) Facilitates Efficient and Well-Accepted Home Titration in Patients with Advanced Parkinson's Disease.

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG; Duodopa®) is used for continuous infusion in advanced Parkinson's disease. To achieve optimal effect, the LCIG dose is individually titrated, traditionally conducted during hospitalization in Sweden. However, dose adjustment depends on surrounding conditions, physical activity, and emotional stress, which is why titration at home could be beneficial. Telemedicine (TM) using a video communication system offers alternative titration procedures, allowing LCIG initiation at home. OBJECTIVE: Study objectives were to show the feasibility of TM for LCIG home titration, evaluate resource use, and assess patient, neurologist, and nurse satisfaction. METHODS: Four clinics enrolled 15 patients to observe efficiency and feasibility of TM-based monitoring. RESULTS: Patient median (range) age was 67 (52-73) years and time since diagnosis was 10 (7-23) years. Median time between LCIG initiation and end of TM-assisted titration was 2.8 (2.0-13.8) days. Median time required for home titration by neurologists, nurses, and patients was (hours:minutes) 1 : 14 (0 : 29-1 : 52), 5 : 49 (2 : 46-10 : 3), and 8 : 53 (4 : 11-14 : 11), respectively. Neurologists and nurses considered this to be less time than required for hospital titration. TM allowed patients 92% free time from start to end of titration. Technical problems associated with TM contacts were rare, mostly related to digital link, and quickly resolved. Patients, neurologists, and nurses were satisfied using TM. No serious adverse events were reported; there was one device complaint (tube occlusion). CONCLUSIONS: In this study, TM-assisted LCIG titration at home was resource-efficient, technically feasible, well-accepted and was deemed satisfactory by patients, neurologists, and nurses.

Ultrafast photovoltaic response in ferroelectric nanolayers.

We show that light drives large-amplitude structural changes in thin films of the prototypical ferroelectric PbTiO3 via direct coupling to its intrinsic photovoltaic response. Using time-resolved x-ray scattering to visualize atomic displacements on femtosecond time scales, photoinduced changes in the unit-cell tetragonality are observed. These are driven by the motion of photogenerated free charges within the ferroelectric and can be simply explained by a model including both shift and screening currents, associated with the displacement of electrons first antiparallel to and then parallel to the ferroelectric polarization direction.

Up-regulation of A1M/α1-microglobulin in skin by heme and reactive oxygen species gives protection from oxidative damage.

During bleeding the skin is subjected to oxidative insults from free heme and radicals, generated from extracellular hemoglobin. The lipocalin α(1)-microglobulin (A1M) was recently shown to have reductase properties, reducing heme-proteins and other substrates, and to scavenge heme and radicals. We investigated the expression and localization of A1M in skin and the possible role of A1M in the protection of skin tissue from damage induced by heme and reactive oxygen species. Skin explants, keratinocyte cultures and purified collagen I were exposed to heme, reactive oxygen species, and/or A1M and investigated by biochemical methods and electron microscopy. The results demonstrate that A1M is localized ubiquitously in the dermal and epidermal layers, and that the A1M-gene is expressed in keratinocytes and up-regulated after exposure to heme and reactive oxygen species. A1M inhibited the heme- and reactive oxygen species-induced ultrastructural damage, up-regulation of antioxidation and cell cycle regulatory genes, and protein carbonyl formation in skin and keratinocytes. Finally, A1M bound to purified collagen I (K(d) = 0.96×10(-6) M) and could inhibit and repair the destruction of collagen fibrils by heme and reactive oxygen species. The results suggest that A1M may have a physiological role in protection of skin cells and matrix against oxidative damage following bleeding.

Macular hole in Behçet's disease.

OBJECTIVE: To investigate the clinical features, prevalence, role of surgical intervention and the visual prognosis of macular holes (MH) in patients with Behcet's disease (BD). MATERIALS AND METHODS: Retrospective study of patients with BD and MH from January 1998 to November 2008. RESULTS: Out of 159 patients, 21 eyes of 17 patients were identified with MH. The mean age was 38.59 (range 23-61) years and the mean follow-up period was 5.1 years (range 13-164 months). The prevalence of MH was 7%. Visual acuity (VA) at the time of presentation ranged from 20/70 to hand-motion. Optical coherence tomography (OCT) findings revealed intraretinal cysts at the edge of the MH. The mean size of MH was 983.6 um; 52% had elevated edges, 43% had flat edges and only one eye (5%) was closed postoperatively. Fluorescein angiography (FA) was consistent with macular ischemia in 76% of the cases. Human leukocyte antigen (HLA) B51 association was found in 14 of the 15 patients investigated. Six patients (out of 17) underwent pars plana vitrectomy. The final VA on their last follow-up ranged from 20/70 to 2/200. Surgical intervention for MH did not result in any visual improvement as compared to non-operated eyes. One patient lost vision completely due to elevated intraocular pressure post vitrectomy and silicon oil tamponade. CONCLUSIONS: MH in patients with BD may lead to significant visual disability. Surgical intervention does not seem to have any potential beneficial effect on the VA, probably due to significant macular ischemia and sequelae from the ocular inflammation.

Subpicosecond hard x-ray streak camera using single-photon counting.

We have developed and characterized a hard x-ray accumulating streak camera that achieves subpicosecond time resolution by using single-photon counting. A high repetition rate of 2 kHz was achieved by use of a readout camera with built-in image processing capabilities. The effects of sweep jitter were removed by using a UV timing reference. The use of single-photon counting allows the camera to reach a high quantum efficiency by not limiting the divergence of the photoelectrons.

Non-contact acoustic cell trapping in disposable glass capillaries.

Non-contact trapping using acoustic standing waves has shown promising results in cell-based research lately. However, the devices demonstrated are normally fabricated using microfabrication or precision machining methods leading to a high unit cost. In e.g. clinical or forensic applications avoiding cross-contamination, carryover or infection is of outmost importance. In these applications disposable devices are key elements, thus making the cost per unit a critical factor. A solution is presented here where low-cost off-the-shelf glass capillaries are used as resonators for standing wave trapping. Single-mode as well as multi-node trapping is demonstrated with an excellent agreement between simulated and experimentally found operation frequencies. Single particle trapping is verified at 7.53 MHz with a trapping force on a 10 microm particle of up to 1.27 nN. The non-contact trapping is proved using confocal microscopy. Finally, an application is presented where the capillary is used as a pipette for aspirating, trapping and dispensing red blood cells.

Triamcinolone-induced cataract in eyes with diabetic macular oedema: 3-year prospective data from a randomized clinical trial.

PURPOSE: To describe the 3-year risk of cataract after intravitreal triamcinolone (IVTA) injections for diabetic macular oedema and the outcomes of cataract surgery. METHODS: Prospective data from a randomized clinical trial were analysed. At baseline, 27 phakic eyes with diabetic macular oedema were randomized to receive IVTA and 25 to receive sham injection. After 2 years, initial sham-treated eyes were eligible to receive IVTA as the study became open label for the third year. The cumulative incidence of cataract surgery was the primary outcome of the study. Other outcomes assessed included progression of cataract, best-corrected logarithm of the minimal angle of resolution visual acuity before and after surgery and central macular thickness. RESULTS: Over the 3 years of the study, 15/27 (56%) phakic eyes in the IVTA treated group underwent cataract surgery as compared with 2/25 (8%) initial sham-treated eyes (P < 0.001). Mean visual acuity 6 months after cataract surgery was better than at entry into the trial. Two (15%) of the eyes in the IVTA-treated group undergoing cataract surgery had a loss of >15 letters. In the IVTA-treated group, 10/15 (67%) eyes that had three or more injections had progression of posterior subcapsular cataract by > or = 2 grades as compared with only 2/12 (17%) eyes that had fewer than three injections (P = 0.009). CONCLUSIONS: Over half of the eyes receiving IVTA injections for diabetic macular oedema required cataract surgery within 3 years. In eyes with three or more IVTA injections, two-thirds had progression of posterior subcapsular cataract. Visual outcomes after cataract surgery were generally good, although a small proportion of eyes lost greater than 15 letters over the course of the study.

PP56 improves energy homeostasis in a mouse model of pancreatic cancer.

In this study, we investigated whether the anti-inflammatory drug PP56 (alpha-trinositol) may improve cancer-induced metabolic disorders. We implanted human MiaPaCa2 pancreatic cancer cells in the pancreas of 14 athymic mice for 12 weeks, using six intact littermates as normal controls. During the 12 weeks, seven tumor-cell recipients were treated with PP56 by daily injection (PPT mice). The tumor-cell recipients that were otherwise untreated were used as tumor controls (TC mice). Impaired glucose tolerance and decreased body weight gain were seen in TC but not PPT mice. When an enzyme for fatty acid beta-oxidation namely medium-chain acyl-CoA dehydrogenase (MCAD) was determined in tumor grafts; tumors from PPT mice showed more MCAD than those from TC mice. This suggests that PP56 stimulated fatty acid beta-oxidation in MiaPaCa2 cells in vivo. In keeping with this notion, PPT mice had decreased plasma free fatty acids. In vitro, we demonstrated that MiaPaCa2 cells consumed more fatty acids in the presence of PP56. In another experiment, we infused PP56 or vehicle in normal mice and found that PP56 decreased circulating glucose in the animals. We also showed that PP56 increased glucose transport in L6 skeletal muscle cells in vitro. In conclusion, PP56 increases the turnover of circulating nutrients such as glucose and helps maintain energy homeostasis in mice with pancreatic cancer.

Increased levels of cell-free hemoglobin, oxidation markers, and the antioxidative heme scavenger alpha(1)-microglobulin in preeclampsia.

Preeclampsia is a major cause of morbidity and mortality during pregnancy. To date, the pathogenesis of the disease is not fully understood. Recent studies show that preeclampsia is associated with overexpression of the hemoglobin genes alpha2 and gamma and accumulation of the protein in the vascular lumen of the placenta. Hypothesizing that cell-free hemoglobin leaks from the placenta into the maternal circulation and contributes to the endothelial damage and symptoms by inducing oxidative stress, we analyzed fetal and adult hemoglobin (HbF, HbA), haptoglobin, oxidation markers, and the heme scavenger and antioxidant alpha(1)-microglobulin in plasma, urine, and placenta in preeclamptic women (n=28) and women with normal pregnancy (n=27). The mean plasma concentrations of HbF, HbA, protein carbonyl groups, membrane peroxidation capacity, and alpha(1)-microglobulin were significantly increased in preeclamptic women. The levels of total plasma Hb correlated strongly with the systolic blood pressure. The plasma haptoglobin concentrations of women with preeclampsia were significantly depressed. Increased amounts of alpha(1)-microglobulin mRNA and protein were found in placenta from preeclamptic women, and the levels of plasma and placenta alpha(1)-microglobulin correlated with the plasma Hb concentrations. The heme-degrading form t-alpha(1)-microglobulin was significantly increased in urine in preeclampsia. These results support the idea that hemoglobin-induced oxidative stress is a pathogenic factor in preeclampsia.

Electrophysiological evaluation and visual outcome in patients with central retinal vein occlusion, primary open-angle glaucoma and neovascular glaucoma.

PURPOSE: To evaluate patients with central retinal vein occlusion (CRVO) and neovascular glaucoma (NVG) using electrophysiology in order to gain better understanding of visual outcome and risk factors, such as previously diagnosed primary open-angle glaucoma (POAG). METHODS: Eighty-three patients (83 eyes) initially presenting with CRVO and examined with full-field electroretinography (ERG) within 3 months of the thrombotic event were analysed retrospectively regarding treatment, risk factors and visual outcome. In addition, 30 patients initially presenting with NVG caused by CRVO were also investigated regarding risk factors using electrophysiology in order to determine the cause of their visual impairment. RESULTS: Nineteen (23%) of the 83 patients initially presenting with CRVO had been diagnosed previously with POAG. Ninety-five per cent (18/19) of all the patients with previously diagnosed glaucoma developed ischaemic CRVO. Thirty-four per cent of the patients initially presenting with CRVO (28/83) developed NVG. Sixty-eight per cent (13/19) of the patients with previous glaucoma developed NVG, compared to 23% (15/64) of the patients without previous POAG. In the patients who initially presented with NVG, full-field ERG demonstrated a remaining retinal function of both cones and rods, indicating that the main cause of visual impairment is ischaemia of the ganglion cell layer. CONCLUSION: Glaucoma is a significant risk factor for developing ischaemic CRVO and subsequent NVG. The presence of POAG in CRVO worsens visual outcome. NVG is associated with preserved photoreceptor function, thus indicating ischaemia of the ganglion cell layer as the primary cause of visual impairment. This emphasizes the importance of prompt treatment of ischaemia and elevated intraocular pressure in these patients.

Increased lipid metabolism and cell turnover of MiaPaCa2 cells induced by high-fat diet in an orthotopic system.

In this study, we investigated whether increased dietary fat influences established pancreatic cancer cells. MiaPaCa2 human pancreatic cancer cells were grown orthotopically in athymic mice fed normal diet (ND) or high-fat diet (HF). In the resulting tumors, medium-chain acyl-coenzyme A dehydrogenase (MCAD, a regulator of fatty acid beta-oxidation) and Cu/Zn-superoxide dismutase (an antioxidant enzyme) were determined using Western blotting. The MCAD messenger RNA (mRNA) was determined by real-time polymerase chain reaction. Intracellular lipid droplets, proliferating cells (Ki67 positive), and apoptotic cells were stained in tumor sections. The HF tumors were heavier than the ND tumors (1.60 +/- 0.08 vs 1.13 +/- 0.10 g, P < .01, 6 tumors per group). The MCAD and Cu/Zn-superoxide dismutase proteins and the MCAD mRNA were increased in HF tumors compared with those seen in ND tumors. The HF tumors contained extensive central necrosis, which was surrounded with apoptotic and proliferating cells. The HF tumors also showed numerous lipid droplets. In the ND tumors, necrosis was uncommon, apoptotic cells were sporadic, and lipid droplets were few. In follow-up experiments, MiaPaCa2 cells were incubated in vitro in the presence or absence of fatty acids (oleic and linoleic acids). The fatty acid exposure increased lipid droplets, cell proliferation, and MCAD mRNA expression in MiaPaCa2 cells. In conclusion, increased dietary fat stimulates lipid metabolism and cell turnover in MiaPaCa2 human pancreatic cancer cells.