High-flux source of coherent XUV pulses for user applications.

We present experimental results obtained at a user-oriented XUV beamline implemented at the ELI Beamlines facility. The coherent XUV radiation is produced via high harmonic generation in gases in a loose focusing geometry. The beamline is designed to be driven by 1 kHz, 100 mJ, 20 fs pulses centered at a wavelength of 830 nm. Results such as XUV spectra, beam wavefront and pulse energy obtained during the beamline commissioning with a commercial 1 kHz, 5 mJ, 40 fs laser system are presented. A unique XUV spectrometer for source characterization designed to reach a very high sensitivity is described in detail, and we demonstrate a novel technique for single-shot and every-shot XUV pulse energy measurement.

Single pulse coherence measurements in the water window at the free-electron laser FLASH.

The spatial coherence of free-electron laser radiation in the water window spectral range was studied, using the third harmonic (λ<(3rd) = 2.66 nm) of DESY's Free-electron LASer in Hamburg (FLASH). Coherent single pulse diffraction patterns of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilamellar lipid stacks have been recorded. The intensity histogram of the speckle pattern around the first lamellar Bragg peak, corresponding to the d = 5 nm periodicity of the stack, reveals an average number of transverse modes of M¯ = 3.0 of the 3rd harmonic. Using the lipid stack as a 'monochromator', pulse-to-pulse fluctuations in the third harmonic λ(3rd) have been determined to be 0.033 nm.

Nonequilibrium collective dynamics in photoexcited lipid multilayers by time resolved diffuse x-ray scattering.

We study the nonequilibrium shape fluctuations in fluorescence labeled phospholipid multibilayers composed of the model lipid DOPC and the well-known lipid dye Texas red, driven out of equilibrium by short laser pulses. The temporal evolution of the lipid bilayer undulations after excitation was recorded by time resolved x-ray diffraction. Already at moderate peak intensities (Pp≤10(5) W/cm2), pulsed laser illumination leads to significant changes of the undulation modes in a well-defined lateral wavelength band. The observed phenomena evolve on nano- to microsecond time scales after optical excitation, and can be described in terms of a modulation instability in the lipid multilamellar stack.

Spatial and temporal coherence properties of single free-electron laser pulses.

The experimental characterization of the spatial and temporal coherence properties of the free-electron laser in Hamburg (FLASH) at a wavelength of 8.0 nm is presented. Double pinhole diffraction patterns of single femtosecond pulses focused to a size of about 10×10 µm(2) were measured. A transverse coherence length of 6.2 ± 0.9 µm in the horizontal and 8.7 ± 1.0 µm in the vertical direction was determined from the most coherent pulses. Using a split and delay unit the coherence time of the pulses produced in the same operation conditions of FLASH was measured to be 1.75 ± 0.01 fs. From our experiment we estimated the degeneracy parameter of the FLASH beam to be on the order of 10(10) to 10(11), which exceeds the values of this parameter at any other source in the same energy range by many orders of magnitude.

Fine needle aspiration biopsy of anaplastic thyroid carcinoma developing from a Hürthle cell tumor: a case report.

BACKGROUND: Anaplastic thyroid carcinoma is a highly malignant tumor in elderly people with a long history of multinodular goiter and is usually associated with a rapidly fatal clinical evolution. The tumor often develops as a result of anaplastic transformation of a slowly growing papillary carcinoma or follicular neoplasm. CASE: An 85-year-old woman had a multinodular goiter and had been asymptomatic, with a normal white blood cell count and chest radiograph three months prior to her hospital admission for the treatment. The tumor presented with low grade fever, leukocytosis, multiple metastatic lung nodules and enlargement of the intrathoracic thyroid in a period of three months, causing compression of the esophagus and trachea. Despite a total thyroidectomy, the tumor recurred within one month and caused dysphagia and death. CONCLUSION: FNAB permitted the diagnosis of an anaplastic thyroid carcinoma arising from an intrathoracic Hürthle cell tumor.

Management of injuries to the anterior cruciate ligament: results of a survey of orthopaedic surgeons in Canada.

OBJECTIVE: To identify the approaches to management of anterior cruciate ligament (ACL) injury by Canadian orthopedic surgeons. METHODS: A questionnaire was mailed to 234 physicians randomly chosen from the Canadian Orthopaedic Association directory to obtain the following information: 1) how orthopaedic surgeons diagnose acute hemarthroses; 2) how patients in any of three common ACL injury scenarios would be managed; 3) what variations exist in surgical technique; and 4) how patient variables such as age, gender, and alignment influence the decision-making process. RESULTS: The return rate was 72%, and 56% of respondents were from academic centers. Patients such as those described in the protocol are routinely managed by 80% of the respondents. The diagnosis of acute hemarthrosis is predominantly made by means of clinical examination and radiographs. Magnetic resonance imaging (MRI) is used occasionally by 43% and routinely by 6% of those who responded; arthroscopy is used routinely by 24%. For the competitive athlete with a complete ACL tear, 64% would recommend reconstruction and 33% would recommend bracing and rehabilitation. For reconstruction, 59% would use bone-patellar tendon-bone (B-PT-B) autograft and 32% would use hamstring tendon autograft; 40% would incorporate the ACL stump during reconstruction. Of the respondents, 77% would advocate ACL reconstruction for competitive athletes with chronic ACL injury. Of these, 63% would use B-PT-B autograft and 27% would use hamstring tendons. If bracing and rehabilitation failed, 98% would recommend ACL reconstruction. In ACL reconstruction, synthetic augmentation would be used by 12% in chronic cases and by 16% in acute cases. In making the decision to perform ACL reconstruction, 53% consider limb alignment to be important and 67% consider moderate patellofemoral pain to be important. Seventy-one percent are influenced by patellofemoral pain when choosing a surgical technique, with a trend toward semitendinosis autograft rather than B-PT-B autograft reconstruction. For the 8-year-old child with an acute ACL injury, 63% of the respondents would recommend rehabilitation and bracing. For the 14-year-old, 45% would recommend rehabilitation and bracing and 37% would recommend ACL reconstruction after physeal closure. CONCLUSION: The results of the survey indicate that, with respect to some of the issues, there is a wide variation in management of acute and chronic ACL injuries among Canadian orthopedic surgeons. Future research and randomized, controlled clinical trials should be directed toward these areas.