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.

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.

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.

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.

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.

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.

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.

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.

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.

The effect of intravitreal triamcinolone on foveal edema in exudative macular degeneration.

PURPOSE: To evaluate the effect of a single intravitreal injection of triamcinolone (IVTA) on central macular thickness and visual acuity in eyes with minimally classic exudative age-related macular degeneration (AMD). DESIGN: Retrospective, nonrandomized clinical interventional study. METHODS: Optical coherence tomography (OCT) and best-corrected logarithm of the minimum angle of resolution visual acuity were performed at baseline and one month after treatment. RESULTS: We identified 11 eyes with foveal edema and minimally classic subfoveal neovascularization treated with an IVTA. Foveal edema decreased significantly from 401 +/- 98 microm at baseline to 295 +/- 141 microm (mean +/- standard deviation; P = .004) at one month. There was, however, no significant change in visual acuity at one or three months after the intervention. CONCLUSIONS: This biological effect of IVTA does not support its clinical use, yet it does warrant further research to determine whether locally delivered corticosteroids may be synergistic with other treatments. Reduction in foveal edema is not necessarily associated with improved visual function in exudative AMD.

Efficacy and safety of multiple intravitreal triamcinolone injections for refractory diabetic macular oedema.

AIM: The efficacy and safety of repeated injections of intravitreal triamcinolone (IVTA) for diabetic macular oedema is unclear, with results of previous reports conflicting. METHODS: This is a prospective, observational case series of 27 eyes receiving IVTA for diabetic macular oedema. LogMAR visual acuity (VA) and central macular thickness (CMT) were measured at baseline and in 3 to 6 monthly intervals for up to 24 months, then correlated with the number of IVTA injections given. RESULTS: One IVTA injection was required in 6 (18%) eyes, 2 in 8 (24%) eyes, 3 in 13 (39%) eyes and 4-5 in 6 (18%) eyes. VA improved in all patients, but neither the final improvement in VA nor the absolute improvement in CMT from baseline to 24 months correlated with the number of injections received (p = 0.44 and 0.84, respectively). Cataract surgery was more frequent in eyes receiving more injections (p = 0.01). CONCLUSIONS: This study suggests that repeated injections of IVTA continue to be as effective as the first over a 2-year period. The probability of cataract surgery increases with an increasing number of injections.

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.

Intravitreal triamcinolone for refractory diabetic macular edema: two-year results of a double-masked, placebo-controlled, randomized clinical trial.

OBJECTIVE: To report 2-year safety and efficacy outcomes from a trial of intravitreal triamcinolone acetonide (TA) injections (4 mg) in eyes with diabetic macular edema and impaired vision that persisted or recurred after laser treatment. DESIGN: Prospective, double-masked, placebo-controlled, randomized clinical trial. PARTICIPANTS AND CONTROLS: Sixty-nine eyes of 43 patients were entered into the study, with 34 eyes randomized to receive active treatment and 35 placebo. Two-year data were available for 60 of 69 (87%) eyes of 35 of 41 (85%) patients; 9 eyes of 6 patients were lost to follow-up, of which 6 received a placebo and 3 received intravitreal TA. INTERVENTION: Triamcinolone acetonide (0.1 ml) was injected through the pars plana using a 27-gauge needle. Eyes randomized to placebo received a subconjunctival injection of saline. MAIN OUTCOME MEASURES: Improvement of best-corrected logarithm of the minimum angle of resolution visual acuity (VA) by > or =5 letters after 2 years and incidence of moderate or severe adverse events. RESULTS: Improvement of > or =5 letters' best-corrected VA was found in 19 of 34 (56%) eyes treated with intravitreal TA, compared with 9 of 35 (26%) eyes treated with the placebo (z(generalized estimating equation) = 2.73, P = 0.006). The mean improvement in VA was 5.7 letters (95% confidence interval, 1.4-9.9) more in the intravitreal TA-treated eyes than in those treated with the placebo. An increase of intraocular pressure (IOP) of > or =5 mmHg was observed in 23 of 34 (68%) treated versus 3 of 30 (10%) untreated eyes (P<0.0001). Glaucoma medication was required in 15 of 34 (44%) treated versus 1 of 30 (3%) untreated eyes (P = 0.0002). Cataract surgery was performed in 15 of 28 (54%) treated versus 0 of 21 (0%) untreated eyes (P<0.0001). Two eyes in the intravitreal TA-treated group required trabeculectomy. There was one case of infectious endophthalmitis in the treatment group. CONCLUSION: Intravitreal TA improves vision and reduces macular thickness in eyes with refractory diabetic macular edema. This beneficial effect persists for up to 2 years with repeated treatment. Progression of cataract and elevation of IOP commonly occur but appear manageable. Spontaneous improvement over years can still occur in eyes that are apparently severely affected by diabetic macular edema.

Relation between reduction of foveal thickness and visual acuity in diabetic macular edema treated with intravitreal triamcinolone.

PURPOSE: To evaluate the correlation between improvement in visual acuity and the reduction of foveal thickness after a single intravitreal injection of 4 mg of triamcinolone in diabetic macular edema. DESIGN: Prospective, interventional, nonrandomized clinical trial. PATIENTS: In a prospective study 24 eyes with diabetic macular edema were treated with an intravitreal injection of 4 mg of triamcinolone acetonide. MAIN OUTCOME MEASURES: Best-corrected logMAR visual acuity and optical coherence tomography were performed at baseline and 3 months after the treatment. RESULTS: At baseline the average foveal thickness was 462 +/- 154 microm (95% confidence interval, 397-527 microm) and at 3 months 257 +/-114 microm (95% confidence interval, 209-305 microm) (P < .0001). The best-corrected logMAR average visual acuity was 60.5 +/- 10.5 (95% confidence interval, 56.0-65.0) ETDRS letters at baseline compared with 65.5 +/- 11.1 (95% confidence interval, 60.8-70.1) 3 months after the injection (P = .0001). There was no correlation between the improvement in visual acuity and the reduction of foveal thickness (r = 0.054, P = .8), but there was a correlation between reduction in foveal thickness and the age of the patients (r = 0.53, P = .008). CONCLUSION: A single injection of 4 mg of intravitreal triamcinolone acetonide effectively reduces the foveal thickness in diabetic macular edema and improves visual acuity, but there does not appear to be a strong correlation between the reduction of foveal thickness and the improvement in visual acuity.

The beer campaign in Stockholm--Attempting to restrict the availability of alcohol to young people.

A number of Swedish studies have indicated that it is easy for underaged youths to purchase medium strength beer in grocery shops. The aim of this study was to follow the effects of a community action-based intervention involving information/training of parents, police, and shopkeepers, media advocacy, and monitoring of the sales of beer to underaged youths. Eighteen-year-old students, looking younger, attempted to purchase a six-pack of medium strength beer in grocery shops without showing ID. A questionnaire about perceived availability was distributed among ninth-grade students. Surveys of parental awareness and shopkeepers' attitudes were also conducted. A significant decrease in sales was observed in both the intervention area (from 73% of all purchase attempts to 44%) and in the comparison area (from 60% to 44%). No significant difference was found between the intervention and the comparison areas, in part due to a contamination effect in the comparison area, where similar activities were conducted by the local community. Perceived availability by teenagers did not change. Following the intervention, availability to medium strength beer for young people in the intervention area decreased, but remained high. It is possible that this moderate reduction was due to the intervention but the same is not certain, given the developments in the comparison area. The intervention was primarily based on information and training, whereas a policy of surveillance and sanctions in the comparison area appears to have achieved the same result, with lesser resources. The study also illustrates the feasibility of engaging parents in community action for prevention purposes.

The relationship between diabetes and pancreatic cancer.

About 80% of pancreatic cancer patients have glucose intolerance or frank diabetes. This observation has led to the following two hypotheses: i. pancreatic cancer causes the associated diabetes and ii. the conditions associated with diabetes promote the development of pancreatic cancer. Evidence supporting both hypotheses has been accumulated in previous studies. This article reviews these studies, especially those that have been conducted recently.

Multifocal electroretinogram in branch retinal vein occlusion.

PURPOSE: To describe the response from multifocal electroretinography in branch retinal vein occlusion. DESIGN: Prospective observational case control series. METHODS: Multifocal electroretinography was recorded in 15 patients with temporal branch retinal vein occlusion and 21 control subjects using a visual evoked response imaging system. RESULTS: There were significant differences in mean amplitude (P =.01) and latency (P =.001) between thrombotic and nonthrombotic retina in the same eyes, as well as in patients compared with control subjects. CONCLUSION: Responses from multifocal electroretinography demonstrate retinal dysfunction in branch retinal vein occlusion; additional studies will demonstrate whether multifocal electroretinography has a prognostic value.