Amplification of ultrashort laser pulses by brillouin backscattering in plasmas

Plasma media, by exciting Raman (electron) or Brillouin (ion) waves, have been used to transfer energy from moderately long, high-energy light pulses to short ones. Using multidimensional kinetic simulations, we define here the optimum window in which a Brillouin scheme can be exploited for amplification and compression of short laser pulses over short distances to very high power. We also show that shaping the plasma allows for increasing the efficiency of the process while minimizing other unwanted plasma processes. Moreover, we show that, contrary to what was traditionally thought (i.e., using Brillouin in gases for nanosecond pulse compression), this scheme is able to amplify pulses of extremely short duration.

Comparison of freehand-navigated and aiming device-navigated targeting of liver lesions

BACKGROUND

Accurate needle placement is crucial for the success of percutaneous radiological needle interventions. We compared three guiding methods using an optical-based navigation system: freehand, using a stereotactic aiming device and active depth control, and using a stereotactic aiming device and passive depth control.

METHODS

For each method, 25 punctures were performed on a non-rigid phantom. Five 1 mm metal screws were used as targets. Time requirements were recorded, and target positioning errors (TPE) were measured on control scans as the distance between needle tip and target.

RESULTS

Time requirements were reduced using the aiming device and passive depth control. The Euclidian TPE was similar for each method (4.6 ± 1.2-4.9 ± 1.7 mm). However, the lateral component was significantly lower when an aiming device was used (2.3 ± 1.3-2.8 ± 1.6 mm with an aiming device vs 4.2 ± 2.0 mm without).

DISCUSSION

Using an aiming device may increase the lateral accuracy of navigated needle insertion.

[A training program for dementia trainers: does this program have practical relevance?]

BACKGROUND

Specific curricula for professionals working in various settings with persons with dementia have been developed and implemented into practice. In this study, the practical relevance of a teaching program for the M.A.S (Morbus Alzheimer syndrome) dementia trainer was evaluated. The curriculum was developed in 2002 within a scientific project. The goal was that care professionals and noncare professionals learn how to support and train persons with dementia and their caregivers. The task of the trainer is to support the functional and emotional resources of the person with dementia employing stage-specific training according to principles of the theory of retrogenesis. Trainers are also able to support family caregivers in their difficult day-to-day care for the person with dementia. With this training and support program, persons with dementia can train their residual capacities and develop a life perspective which enables them to cope with the long duration of Alzheimer's disease.

MATERIALS AND METHODS

The curriculum for the training methodology is based in the theory of retrogenesis. The 1-year training course is held in the form of modules and includes the following topics: (1) stages of dementia and medical aspects, (2) communication with persons with dementia, (3) stage-specific retrogenic training, (4) physical training for the elderly and persons with dementia, (5) coaching family caregivers through the long disease duration, and (6) care issues for persons without education in care. M.A.S trainers were questioned after they had concluded the teaching program successfully and had the chance to apply the content of the teaching program in their practical work. A short questionnaire was sent via e-mail or a telephone interview was performed.

RESULTS

A total of 279 trainers graduated and were certified. Of these, 140 persons (53.6% of the population) could be questioned after an average of 2.69 years after completion of the course: 93.6% of trainees were still using the principles of the teaching course successfully; of these, 56% were working in the function of a trainer full time and 44% used the principles within their work environment (mainly in the nursing home environment).

CONCLUSION

The study found that the majority of questioned trainers are still using the principles taught in the course successfully with persons with dementia living at home and the content was found to be relevant for practice. The content of the teaching course, applying principles of retrogenesis, which was originally designed for persons with dementia living at home, can also be successfully applied in the nursing home environment. Increasing interest has been shown by institutions employing professionals whose task it is to keep persons with dementia active and interested as well as physically functioning at their best possible level. As a consequence, persons with dementia perceive higher quality of life and exhibit fewer behavior problems which complicate care. More research is needed to accumulate evidence and to support these findings.

Charged-particle spectroscopy for diagnosing shock ρR and strength in NIF implosions

The compact Wedge Range Filter (WRF) proton spectrometer was developed for OMEGA and transferred to the National Ignition Facility (NIF) as a National Ignition Campaign diagnostic. The WRF measures the spectrum of protons from D-(3)He reactions in tuning-campaign implosions containing D and (3)He gas; in this work we report on the first proton spectroscopy measurement on the NIF using WRFs. The energy downshift of the 14.7-MeV proton is directly related to the total ρR through the plasma stopping power. Additionally, the shock proton yield is measured, which is a metric of the final merged shock strength.

Diagnosing radiative shocks from deuterium and tritium implosions on NIF

During the recent ignition tuning campaign at the National Ignition Facility, layered cryogenic deuterium and tritium capsules were imploded via x-ray driven ablation. The hardened gated x-ray imager diagnostic temporally and spatially resolves the x-ray emission from the core of the capsule implosion at energies above ~8 keV. On multiple implosions, ~200-400 ps after peak compression a spherically expanding radiative shock has been observed. This paper describes the methods used to characterize the radial profile and rate of expansion of the shock induced x-ray emission.

[Quality of life for adolescents with vocal cord dysfunction]

BACKGROUND

Vocal cord dysfunction (VCD) is a functional breathing disorder. A psychosomatic aetiology has been discussed and associations with depression, anxiety disorders, and social stress have been reported. We have undertaken a screening of behavioural and emotional problems in adolescent patients using standardised questionnaires.

METHODS

Thirty-one patients (8 - 16 years) with the clinical suspicion of VCD were investigated using the Youth-Self-Report (YSR/11 - 18) and for the assessment of the parents we used the analoguous Child-Behaviour-Checklist (CBCL/6 - 18). YSR and CBCL contain two sub-areas: (a) competence scales that measure the child's participation in activities, social skills and school achievements and (b) items that contain subscales for emotional problems such as depressive and anxiety symptoms, conduct problems such as oppositional defiant problems and aggressive behaviour, social problems and physical complaints.

RESULTS

On average, the features of VCD patients were not significantly different from those of the reference population. But we did observe tendencies of psychological problems (YSR 16.7 %, CBCL 20 %) compared with the standard (2 %) in the syndrome scales of both questionnaires Adolescents reported particularly more internalising disorders such as social retreat, physical complaint and anxiety and depressive symptoms. The parents reported more often "physical complaints" (13.3 %) and "aggressive behaviour" (10 %).

CONCLUSIONS

We found tendencies of psychological strain, mainly social retreat, physical complaints and anxiety and depressive symptoms. Further investigations should focus on those emotional problems as well as on psychosomatically caused physical problems. Personality and psychological stress of the parents should be included in the investigation in order to evaluate the reports of the parents on higher aggressive behaviour and enhanced physical problems of their children in relation to their own psychological strain. We suggest family therapies, family counselling, or parental coaching as a therapeutic approach.

The World Organisation for Animal Health and epidemiological modelling: background and objectives

The papers in this issue of the Scientific and Technical Review (the Review) examine uses of modelling as a tool to supportthe formulation of disease control policy and applications of models for various aspects of animal disease management. Different issues in model development and several types of models are described. The experience with modelling during the 2001 foot and mouth disease outbreak in the United Kingdom underlines how models might be appropriately applied by decision-makers when preparing for and dealing with animal health emergencies. This paper outlines the involvement of the World Organisation for Animal Health (OIE) in epidemiological modelling since 2005, with emphasis on the outcome of the 2007 questionnaire survey of model usage among Member Countries, the subsequent OIE General Session resolution and the 2008 epidemiological modelling workshop at the Centers for Epidemiology and Animal Health in the United States. Many of the workshop presentations were developed into the papers that are presented in this issue of the Review.

Lysine-specific demethylase 1 restricts hematopoietic progenitor proliferation and is essential for terminal differentiation

Lysine (K)-specific demethylase 1A (LSD1/KDM1A) has been identified as a potential therapeutic target in solid cancers and more recently in acute myeloid leukemia. However, the potential side effects of a LSD1-inhibitory therapy remain elusive. Here, we show, with a newly established conditional in vivo knockdown model, that LSD1 represents a central regulator of hematopoietic stem and progenitor cells. LSD1 knockdown (LSD1-kd) expanded progenitor numbers by enhancing their proliferative behavior. LSD1-kd led to an extensive expansion of granulomonocytic, erythroid and megakaryocytic progenitors. In contrast, terminal granulopoiesis, erythropoiesis and platelet production were severely inhibited. The only exception was monopoiesis, which was promoted by LSD1 deficiency. Importantly, we showed that peripheral blood granulocytopenia, monocytosis, anemia and thrombocytopenia were reversible after LSD1-kd termination. Extramedullary splenic hematopoiesis contributed to the phenotypic reversion, and progenitor populations remained expanded. LSD1-kd was associated with the upregulation of key hematopoietic genes, including Gfi1b, Hoxa9 and Meis1, which are known regulators of the HSC/progenitor compartment. We also demonstrated that LSD1-kd abrogated Gfi1b-negative autoregulation by crossing LSD1-kd with Gfi1b:GFP mice. Taken together, our findings distinguish LSD1 as a critical regulator of hematopoiesis and point to severe, but reversible, side effects of a LSD1-targeted therapy.