Frequency-domain interferometry for the determination of time delay between two extreme-ultraviolet wave packets generated by a tandem undulator.

Synchrotron radiation, emitted by relativistic electrons traveling in a magnetic field, has poor temporal coherence. However, recent research has proved that time-domain interferometry experiments, which were thought to be enabled by only lasers of excellent temporal coherence, can be implemented with synchrotron radiation using a tandem undulator. The radiation generated by the tandem undulator comprises pairs of light wave packets, and the longitudinal coherence within a light wave packet pair is used to achieve time-domain interferometry. The time delay between two light wave packets, formed by a chicane for the electron trajectory, can be adjusted in the femtosecond range by a standard synchrotron technology. In this study, we show that frequency-domain spectra of the tandem undulator radiation exhibit fringe structures from which the time delay between a light wave packet pair can be determined with accuracy on the order of attoseconds. The feasibility and limitations of the frequency-domain interferometric determination of the time delay are examined.

Time domain double slit interference of electron produced by XUV synchrotron radiation.

We present a new realization of the time-domain double-slit experiment with photoelectrons, demonstrating that spontaneous radiation from a bunch of relativistic electrons can be used to control the quantum interference of single-particles. The double-slit arrangement is realized by a pair of light wave packets with attosecond-controlled spacing, which is naturally included in the spontaneous radiation from two undulators in series. Photoelectrons emitted from helium atoms are observed in the energy-domain under the condition of detecting them one by one, and the stochastic buildup of the quantum interference pattern on a detector plane is recorded.

Double-pulsed wave packets in spontaneous radiation from a tandem undulator.

We verify that each wave packet of spontaneous radiation from two undulators placed in series has a double-pulsed temporal profile with pulse spacing which can be controlled at the attosecond level. Using a Mach-Zehnder interferometer operating at ultraviolet wavelengths, we obtain the autocorrelation trace for the spontaneous radiation from the tandem undulator. The results clearly show that the wave packet has a double-pulsed structure, consisting of a pair of 10-cycle oscillations with a variable separation. We also report the characterization of the time delay between the double-pulsed components in different wavelength regimes. The excellent agreement between the independent measurements confirms that a tandem undulator can be used to produce double-pulsed wave packets at arbitrary wavelength.

Electron Wave Packet Interference in Atomic Inner-Shell Excitation.

We report the observation of quantum interference between electron wave packets launched from the inner-shell 4d orbital of the Xe atom. Using pairs of femtosecond radiation wave packets from a synchrotron light source, we obtain time-domain interferograms for the inner-shell excitations. This approach enables the experimental verification and control of the quantum interference between the electron wave packets. Furthermore, the femtosecond Auger decay of the inner-shell excited state is tracked. To the best of our knowledge, this is the first observation of wave packet interference in an atomic inner-shell process, and also the first time-resolved experiment on few-femtosecond Auger decay using a synchrotron light source.

Controlling the Orbital Alignment in Atoms Using Cross-Circularly Polarized Extreme Ultraviolet Wave Packets.

We report on the use of pairs of 10-cycle extreme ultraviolet wave packets with attosecond-controlled spacing emitted by individual relativistic electrons within an electron bunch passing through a tandem undulator. Based on the temporal coherent control technique with circular polarization, we succeeded in controlling the excited state alignment in the photoexcitation of helium atoms, which we verified through the observation of oscillation in fluorescence yield depending on the attosecond-controlled delay time. Our work demonstrates the potential of undulator radiation for the generation of longitudinally coherent wave packets suitable for attosecond coherent control, an application which has hitherto been hidden in the incoherent nature of the radiation pulse emitted by a bunch of electrons.

Coherent control in the extreme ultraviolet and attosecond regime by synchrotron radiation.

Quantum manipulation of populations and pathways in matter by light pulses, so-called coherent control, is currently one of the hottest research areas in optical physics and photochemistry. The forefront of coherent control research is moving rapidly into the regime of extreme ultraviolet wavelength and attosecond temporal resolution. This advance has been enabled by the development of high harmonic generation light sources driven by intense femtosecond laser pulses and by the advent of seeded free electron laser sources. Synchrotron radiation, which is usually illustrated as being of poor temporal coherence, hitherto has not been considered as a tool for coherent control. Here we show an approach based on synchrotron radiation to study coherent control in the extreme ultraviolet and attosecond regime. We demonstrate this capability by achieving wave-packet interferometry on Rydberg wave packets generated in helium atoms.

Acute outcome of chronic total occlusion (CTO) recanalizsation in the elderly.

OBJECTIVES: Percutaneous coronary intervention (PCI) of total chronic total occlusion (CTO) still remains a major challenge in interventional cardiology. There is only insignificant knowledge reported in the literature about age differences in CTO recanalization. We analyzed in this study the issue of the impact of age on procedural characteristics, complications and short-term outcome. METHODS: Between 2012-2016 we included 440 patients. They underwent PCI for at least one CTO. Antegrade and retrograde CTO techniques were applied. The retrograde approach was used only after failed antegrade intervention. Continuous data are presented as the mean ± standard deviation; categorical data are presented as numbers and percentages unless otherwise specified. We used Twosamplet- t-test with equal variance to test the significant differences of the variables between the two cohorts. RESULTS: Procedural success proved independently of age. There was no significant interaction between age and procedural success (p=0.5). Complication rates were low in both groups (2.7% vs. 4%; p=0,4) with no difference in statistical significance. CONCLUSIONS: Our study suggests that in an aging society patients with severe coronary artery disease and chronical total occlusions an interventional therapy should be used more intensively. It can be performed safe and feasible.

Helical Phase Structure of Radiation from an Electron in Circular Motion.

We theoretically show that a single free electron in circular motion radiates an electromagnetic wave possessing helical phase structure, which is closely related to orbital angular momentum carried by it. We experimentally demonstrate it by interference and double-slit diffraction experiments on radiation from relativistic electrons in spiral motion. Our results indicate that photons carrying orbital angular momentum should be created naturally by cyclotron/synchrotron radiations or Compton scatterings in various situations in cosmic space. We propose promising laboratory vortex photon sources in various wavelengths ranging from radio wave to gamma-rays.

Angular Momentum of Twisted Radiation from an Electron in Spiral Motion.

We theoretically demonstrate for the first time that a single free electron in circular or spiral motion emits twisted photons carrying well-defined orbital angular momentum along the axis of the electron circulation, in adding to spin angular momentum. We show that, when the electron velocity is relativistic, the radiation field contains harmonic components and the photons of lth harmonic carry lℏ total angular momentum for each. This work indicates that twisted photons are naturally emitted by free electrons and are more ubiquitous in laboratories and in nature than ever thought.

Characterization of unexpected postural changes during robot-assisted gait training in paraplegic patients.

STUDY DESIGN: This is a retrospective study. OBJECTIVES: The objectives of this study were to categorize unexpected postural changes (UPCs) during gait training in paraplegic patients with wearable gait-assist robots, to reveal the incidence of the UPC and its time-dependent changes during initial gait training period and to investigate neurological level-specific differences. SETTING: This study was conducted in Fujita Health University, Aichi, Japan. METHODS: We investigated five patients (46.2±14.6 years; lesion level: T6:3, T12:2). All patients had previously achieved gait with wearable robot and walker at supervision level. The UPCs were counted for 2 years and classified according to their type. The time-course data were calculated from the incidence of UPCs for 10 days from initial gait training with the walker. The neurological level-specific differences were investigated between T6 and T12 injuries. RESULTS: Eighty-five UPCs were observed and classified into three categories: anterior breakdown, posterior breakdown (PBD) and mal-timing. The average rate over the entire period was 0.96±0.62 (incidents/h/subject). PBD, which was defined as hyperflexion of both hip joints, occurred with the highest frequency (0.64±0.64 incidents/h/subject). During initial gait training, there was a gradual decrease in the occurrence of UPC. For neurological level-specific differences, UPCs were observed more frequently in T6 injuries (1.36±0.35 incidents/h/subject) compared with T12 injuries (0.36±0.31 incidents/h/subject). CONCLUSION: PBDs might be the result of near collisions between the trunk of the user and the walker, which make it difficult for the users to move their trunk over an anterior stance limb. Training that is focused upon well-timed forward movements of the walker might be required to avoid the occurrence of this common UPC.

Randomized clinical trial of adjuvant chemotherapy with S-1 versus gemcitabine after pancreatic cancer resection.

BACKGROUND: Randomized studies of adjuvant chemotherapy using gemcitabine suggest a survival benefit after resection of pancreatic cancer. S-1 has also been shown to prolong survival in patients with unresectable pancreatic cancer. This study compared the effects of adjuvant chemotherapy with S-1 or gemcitabine after resection of pancreatic cancer in a randomized trial. METHODS: Patients who had undergone resection of pancreatic cancer were registered in this randomized clinical trial. The primary endpoint was disease-free survival (DFS). Expression levels of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) mRNAs in cancer tissues were measured as indicators of fluoropyrimidine sensitivity. RESULTS: Of 57 patients registered, 29 were allocated to the S-1 group and 28 to gemcitabine. DFS tended to be better with S-1 (median 14·6 (90 per cent c.i. 8·8 to 28·4) months versus 10·5 (7·0 to 28·4) months in the gemcitabine group; P = 0·188), with a similar pattern for overall survival: 21·5 (95 per cent c.i. 14·4 to 42·3) and 18·0 (13·3 to 42·8) months respectively (P = 0·293). When patients were divided into subgroups based on high or low DPD and TS expression, those with a DPD level below the median of 0·88 or a TS level of at least 2·00 had a significant prolongation of DFS after S-1 treatment compared with gemcitabine (P = 0·008 and P = 0·035 respectively). CONCLUSION: Overall, S-1 did not improve DFS compared with gemcitabine after pancreatic cancer resection, but there seemed to be a DFS advantage in patients with low expression of DPD or high expression of TS. Reference number: UMIN000009118 (http://www.umin.ac.jp/ctr/).

Tissue invasion and metastasis: Molecular, biological and clinical perspectives.

Cancer is a key health issue across the world, causing substantial patient morbidity and mortality. Patient prognosis is tightly linked with metastatic dissemination of the disease to distant sites, with metastatic diseases accounting for a vast percentage of cancer patient mortality. While advances in this area have been made, the process of cancer metastasis and the factors governing cancer spread and establishment at secondary locations is still poorly understood. The current article summarizes recent progress in this area of research, both in the understanding of the underlying biological processes and in the therapeutic strategies for the management of metastasis. This review lists the disruption of E-cadherin and tight junctions, key signaling pathways, including urokinase type plasminogen activator (uPA), phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene (PI3K/AKT), focal adhesion kinase (FAK), ß-catenin/zinc finger E-box binding homeobox 1 (ZEB-1) and transforming growth factor beta (TGF-ß), together with inactivation of activator protein-1 (AP-1) and suppression of matrix metalloproteinase-9 (MMP-9) activity as key targets and the use of phytochemicals, or natural products, such as those from Agaricus blazei, Albatrellus confluens, Cordyceps militaris, Ganoderma lucidum, Poria cocos and Silybum marianum, together with diet derived fatty acids gamma linolenic acid (GLA) and eicosapentanoic acid (EPA) and inhibitory compounds as useful approaches to target tissue invasion and metastasis as well as other hallmark areas of cancer. Together, these strategies could represent new, inexpensive, low toxicity strategies to aid in the management of cancer metastasis as well as having holistic effects against other cancer hallmarks.

[Options and Limitations in Endovascular Therapy for Acute and Chronic Mesenteric Arterial Occlusions]. / Endovaskuläre Möglichkeiten und Grenzen bei akuten und chronischen mesenterialen Verschlussprozessen.

BACKGROUND: The significance of endovascular therapy for mesenteric ischaemia (MI) is being debated. Despite initially lower mortality and morbidity, inconsistent early and late results led to questions concerning indications and technical applications of the procedure. METHODS: 91 patients with MI underwent endovascular treatment in a period of 11 years. In 78 (85.7 %) patients a stent was deployed and in 13 (14.3 %) an angioplasty was performed, principally of the superior mesenteric artery (n = 81/91, 89 %). Follow-up consisted of a clinical and an ultrasound examination in all cases. Mean follow-up was 4.2 years. Our results were compared to those in the literature. RESULTS: Endovascular treatment of the intestinal arteries accounted for 0.6 % of all vascular procedures. Seven of 91 patients (7.7 %) died after an initial PTA/stenting. The overall peri-interventional morbidity was 6.6 % (n = 6/91). Medium- to long-term complications were encountered in 20 patients (22 %), primarily during the first year (85 %). Six of 91 patients developed an in-stent stenosis (6.6 %) and 14/91 patients (15.4 %) stent occlusion. Additionally 2 dislocated stents (2.2 %) and an arterial perforation with bleeding into the mesentery (1.1 %) were seen. Although 3 of these 20 patients were successfully treated with an additional PTA or stenting (15.0 %; n = 3/91, 3.3 %), surgical conversion was necessary in 9 (n = 9/20, 45 %; n = 9/91, 9.9 %). The postoperative mortality was respectively 22.2 % (n = 2/9; n = 2/91, 2.2 %). In the case of acute MI, endovascular procedures are only indicated for patients without peritonitis. In chronic MI, the indication for endovascular treatment depends on the type of occlusion and the vascular anatomy. Despite favourable early results, the outcome of endovascular treatment deteriorates with time reaching a 1-year patency rate of 63 % in a multicentre analysis. This leads to secondary procedures in 30 %. A surgical conversion carries a high mortality. CONCLUSION: The endovascular treatment of intestinal artery disease cannot be considered the treatment of choice, it is rather an alternative method in patients with functional or local contraindications to surgery. Life-long follow-up is necessary to prevent stent complications with fatal consequences. A prospective randomised study concerning the evaluation of the advantages and disadvantages of surgical and endovascular therapy of intestinal artery occlusive disease is required.

Microbunching instability in relativistic electron bunches: direct observations of the microstructures using ultrafast YBCO detectors.

Relativistic electron bunches circulating in accelerators are subjected to a dynamical instability leading to microstructures at millimeter to centimeter scale. Although this is a well-known fact, direct experimental observations of the structures, or the field that they emit, remained up to now an open problem. Here, we report the direct, shot-by-shot, time-resolved recording of the shapes (including envelope and carrier) of the pulses of coherent synchrotron radiation that are emitted, and that are a "signature" of the electron bunch microstructure. The experiments are performed on the UVSOR-III storage ring, using electrical field sensitive YBa2Cu3O(7-x) thin-film ultrafast detectors. The observed patterns are subjected to permanent drifts, that can be explained from a reasoning in phase space, using macroparticle simulations.

[Ureteroarterial fistula - pathogenesis, diagnostics, and therapeutic outcome]. / Die uretero-arterielle Fistel - Ursachen, Diagnostik und Therapieergebnisse.

Although ureteroarterial fistulas are rare, they result in a high mortality because of the massive urogenital haemorrhage. The diagnosis is often difficult even when invasive measures are applied. Including the ureteroarterial fistula in the diagnostic process in cases of macrohaematuria with a positive medical history can be helpful. A ureteroarterial fistula typically develops in pa-tients who have undergone pelvic surgery and radiation as well as after long-term ureteral stents. Patients are usually multimorbid. The treatment of choice consists of fistula exclusion by stent graft deployment in the iliac artery and application of a ureteral stent or a ureterostomy. The significance of surgical treatment is diminishing. The long-term results of endovascular treatment, however, are inconsistent because of stent infections and recurrent bleeding. Therefore, close patient surveillance and cooperation among the treating specialists is necessary.·

Three-year results after directional atherectomy of calcified stenotic lesions of the superficial femoral artery.

OBJECTIVE: To investigate the 3-year outcome of patients with peripheral arterial disease (PAD) and heavily calcified stenotic lesions of the superficial femoral artery after directional atherectomy. MATERIALS AND METHODS: Fifty-three patients (mean age 67 ± 10 years; 18 females, 35 males, TASC B and C, mean lesion length 7.9 ± 3.5 cm) with PAD (Rutherford 2-6) were enrolled into this prospective monocentric study. In total, 59 calcified lesions of the superficial femoral artery were treated with the Silverhawk atherectomy device (Covidien, Plymouth, MN, USA). Patients were followed-up for 36 months with a 6-month interval to perform clinical re-evaluation, including measurement of maximum walking distance and ankle-brachial index (ABI) as well as duplex-sonography. RESULTS: The primary success rate of the procedure was 92 %. In five cases (8 %), additional balloon-PTA and/or stent-PTA was necessary. Procedure-related embolization occurred in seven cases (12 %), which were all successfully treated by aspiration. The primary patency rate after 3 years was 55 %. Median Rutherford score decreased significantly from 5 to 0 after 36 months (p < 0.001). At the same time, the ABI increased from 0.65 to 1.12 (not significant). The limb-salvage rate after 3 years was 87 %. CONCLUSION: In this subgroup of patients with POD and calcified stenotic lesions, atherectomy was successfully applied to decrease the plaque burden. Results after 3 years showed a significant decrease of Rutherford score with persistent improvement of ABI and reasonable patency rate.

Mechanical thrombectomy of iliac vein thrombosis in a pig model using the Rotarex and Aspirex catheters.

PURPOSE: To investigate the efficacy and safety of mechanical thrombectomy for iliac vein thrombosis using Rotarex and Aspirex catheters in a pig model. MATERIALS AND METHODS: Iliac vein thrombosis was induced in six pigs by means of an occlusion-balloon catheter and thrombin injection. The presence of thrombi was verified by digital subtraction angiography (DSA) and computed tomography (CT). Thrombectomy was performed using 6F and 8F Rotarex and 6F, 8F, and 10F Aspirex catheters (Straub Medical AG, Wangs, Switzerland). After intervention, DSA and CT were repeated to evaluate the efficacy of mechanical thrombectomy and to exclude local complications. In addition, pulmonary CT was performed to rule out pulmonary embolism. Finally, all pigs were killed, and iliac veins were dissected to perform macroscopic and histological examination. RESULTS: Thrombus induction was successfully achieved in all animals as verified by DSA and CT. Subsequent thrombectomy lead to incomplete recanalization of the iliac veins with residual thrombi in all cases. However, the use of the 6F and 8F Rotarex catheters caused vessel perforation and retroperitoneal hemorrhage in all cases. Application of the Aspirex device caused one small transmural perforation in a vessel treated with a 10F Aspirex catheter, and this was only seen microscopically. Pulmonary embolism was detected in one animal treated with the Rotarex catheters, whereas no pulmonary emboli were seen in animals treated with the Aspirex catheters. CONCLUSION: The Aspirex catheter allowed subtotal and safe recanalization of iliac vein thrombosis. In contrast, the use of the Rotarex catheter caused macroscopically obvious vessel perforations in all cases.