Combining laser interferometry and plasma spectroscopy for spatially resolved high-sensitivity plasma density measurements in discharge capillaries

Precise characterization and tailoring of the spatial and temporal evolution of plasma density within plasma sources are critical for realizing high-quality accelerated beams in plasma wakefield accelerators. The simultaneous use of two independent diagnostics allowed the temporally and spatially resolved detection of plasma density with unprecedented sensitivity and enabled the characterization of the plasma temperature in discharge capillaries for times later than 0.5 µs after the initiation of the discharge, at which point the plasma is at local thermodynamic equilibrium. A common-path two-color laser interferometer for obtaining the average plasma density with a sensitivity of 2 × 10¹⁵ cm^-2 was developed together with a plasma emission spectrometer for analyzing spectral line broadening profiles with a resolution of 5 × 10¹⁵ cm^-3. Both diagnostics show good agreement when applying the spectral line broadening analysis methodology of Gigosos and Cardeñoso in the temperature range of 0.5 eV-5.0 eV. For plasma with densities of 0.5-2.5 × 10¹⁷ cm^-3, temperatures of 1 eV-7 eV were indirectly measured by combining the diagnostic information. Measured longitudinally resolved plasma density profiles exhibit a clear temporal evolution from an initial flat-top to a Gaussian-like shape in the first microseconds as material is ejected out from the capillary. These measurements pave the way for highly detailed parameter tuning in plasma sources for particle accelerators and beam optics.

FLASHForward: plasma wakefield accelerator science for high-average-power applications

The FLASHForward experimental facility is a high-performance test-bed for precision plasma wakefield research, aiming to accelerate high-quality electron beams to GeV-levels in a few centimetres of ionized gas. The plasma is created by ionizing gas in a gas cell either by a high-voltage discharge or a high-intensity laser pulse. The electrons to be accelerated will either be injected internally from the plasma background or externally from the FLASH superconducting RF front end. In both cases, the wakefield will be driven by electron beams provided by the FLASH gun and linac modules operating with a 10 Hz macro-pulse structure, generating 1.25 GeV, 1 nC electron bunches at up to 3 MHz micro-pulse repetition rates. At full capacity, this FLASH bunch-train structure corresponds to 30 kW of average power, orders of magnitude higher than drivers available to other state-of-the-art LWFA and PWFA experiments. This high-power functionality means FLASHForward is the only plasma wakefield facility in the world with the immediate capability to develop, explore and benchmark high-average-power plasma wakefield research essential for next-generation facilities. The operational parameters and technical highlights of the experiment are discussed, as well as the scientific goals and high-average-power outlook. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Tunable Plasma-Based Energy Dechirper

A tunable plasma-based energy dechirper has been developed at FLASHForward to remove the correlated energy spread of a 681 MeV electron bunch. Through the interaction of the bunch with wakefields excited in plasma the projected energy spread was reduced from a FWHM of 1.31% to 0.33% without reducing the stability of the incoming beam. The experimental results for variable plasma density are in good agreement with analytic predictions and three-dimensional simulations. The proof-of-principle dechirping strength of 1.8  GeV/mm/m significantly exceeds those demonstrated for competing state-of-the-art techniques and may be key to future plasma wakefield-based free-electron lasers and high energy physics facilities, where large intrinsic chirps need to be removed.

A Terminological and Ontological Analysis of the NCI Thesaurus

Objective: The National Cancer Institute Thesaurus is described by its authors as “a biomedical vocabulary that provides consistent, unambiguous codes and definitions for concepts used in cancer research” and which “exhibits ontology-like properties in its construction and use”. We performed a qualitative analysis of the Thesaurus in order to assess its conformity with principles of good practice in terminology and ontology design.

Materials and Methods: We used both the on-line browsable version of the Thesaurus and its OWL-representation (version 04.08b, released on August 2, 2004), measuring each in light of the requirements put forward in relevant ISO terminology standards and in light of ontological principles advanced in the recent literature.

Results: We found many mistakes and inconsistencies with respect to the term-formation principles used, the underlying knowledge representation system, and missing or inappropriately assigned verbal and formal definitions.

Conclusion: Version 04.08b of the NCI Thesaurus suffers from the same broad range of problems that have been observed in other biomedical terminologies. For its further development, we recommend the use of a more principled approach that allows the Thesaurus to be tested not just for internal consistency but also for its degree of correspondence to that part of reality which it is designed to represent.

A revisionist history of adult marrow stem cell biology or 'they forgot about the discard'

The adult marrow hematopoietic stem cell biology has largely been based on studies of highly purified stem cells. This is unfortunate because during the stem cell purification the great bulk of stem cells are discarded. These cells are actively proliferating. The final purified stem cell is dormant and not representative of the whole stem cell compartment. Thus, a large number of studies on the cellular characteristics, regulators and molecular details of stem cells have been carried on out of non-represented cells. Niche studies have largely pursued using these purified stem cells and these are largely un-interpretable. Other considerations include the distinction between baseline and transplant stem cells and the modulation of stem cell phenotype by extracellular vesicles, to cite a non-inclusive list. Work needs to proceed on characterizing the true stem cell population.

Mesenchymal stromal cell-derived extracellular vesicles rescue radiation damage to murine marrow hematopoietic cells

Mesenchymal stromal cells (MSCs) have been shown to reverse radiation damage to marrow stem cells. We have evaluated the capacity of MSC-derived extracellular vesicles (MSC-EVs) to mitigate radiation injury to marrow stem cells at 4 h to 7 days after irradiation. Significant restoration of marrow stem cell engraftment at 4, 24 and 168 h post irradiation by exposure to MSC-EVs was observed at 3 weeks to 9 months after transplant and further confirmed by secondary engraftment. Intravenous injection of MSC-EVs to 500cGy exposed mice led to partial recovery of peripheral blood counts and restoration of the engraftment of marrow. The murine hematopoietic cell line, FDC-P1 exposed to 500cGy, showed reversal of growth inhibition, DNA damage and apoptosis on exposure to murine or human MSC-EVs. Both murine and human MSC-EVs reverse radiation damage to murine marrow cells and stimulate normal murine marrow stem cell/progenitors to proliferate. A preparation with both exosomes and microvesicles was found to be superior to either microvesicles or exosomes alone. Biologic activity was seen in freshly isolated vesicles and in vesicles stored for up to 6 months in 10% dimethyl sulfoxide at -80 °C. These studies indicate that MSC-EVs can reverse radiation damage to bone marrow stem cells.

Relation between drug-induced central nervous system effects and plasma levels of diazepam in man

Pharmacodynamic effects and plasma levels of diazepam were studied in healthy male volunteers at different dose levels. Responses to diazepam were quantified, using instruments which measured body sway (statometry) and psychomotor performance (stressalyser tests). High dose-related correlations were obtained between drug-induced changes in test parameters and drug plasma levels, both with regard to stimulant and depressive effects. Techniques were devised for evaluating and comparing the efficacy and usefulness of different types of tests, taking into account critical thresholds, slopes and error estimates, correcting for changes in predrug levels and control (nondrug) trials.

The sociodemographic patterning of opposition to raising taxes on tobacco and restricting tobacco advertisements in Argentina

BACKGROUND

Argentina has enacted important tobacco control initiatives in recent years. Yet little is known about the social patterning of attitudes toward tobacco control. Research is needed to explore what predicts opposition to tobacco control initiatives such as higher taxes on tobacco and the prohibition of tobacco advertising.

STUDY DESIGN

Secondary analysis of Argentina's Global Adult Tobacco Survey (N = 6645).

METHODS

Binary logistic regression analysis examining opposition to raising tobacco taxes and banning tobacco publicity. Models were stratified by smoking status.

RESULTS

Respondents generally indicated very little opposition to either tobacco control measure, with only 15.6% of respondents opposed to increasing taxes on tobacco products and 9.6% opposed to banning tobacco advertisements. Smoking status is the most important predictor of opposition to increasing taxes (OR = 7.85, 95% CI = 6.60-9.34) and banning advertisements (OR = 1.72, 95% CI = 1.39-2.11). Opposition to these measures is most likely among young respondents (aged 15-24) and least likely among older age groups (55-64 and 65 or over), compared to the 25-34 age group. Stratified models suggest that the effect of age may be different for smokers and non-smokers. Low income is a significant predictor of opposition, but only in stratified models for smokers.

CONCLUSION

There is general support for stronger tobacco control measures in Argentina. Opposition to raising taxes on tobacco products and banning tobacco advertisement appears to be concentrated among young smokers with low and medium levels of household income.

Overexpression of ERG in cord blood progenitors promotes expansion and recapitulates molecular signatures of high ERG leukemias

High expression of the ETS family transcription factor ERG is associated with poor clinical outcome in acute myeloid leukemia (AML) and acute T-cell lymphoblastic leukemia (T-ALL). In murine models, high ERG expression induces both T-ALL and AML. However, no study to date has defined the effect of high ERG expression on primary human hematopoietic cells. In the present study, human CD34+ cells were transduced with retroviral vectors to elevate ERG gene expression to levels detected in high ERG AML. RNA sequencing was performed on purified populations of transduced cells to define the effects of high ERG on gene expression in human CD34+ cells. Integration of the genome-wide expression data with other data sets revealed that high ERG drives an expression signature that shares features of normal hematopoietic stem cells, high ERG AMLs, early T-cell precursor-ALLs and leukemic stem cell signatures associated with poor clinical outcome. Functional assays linked this gene expression profile to enhanced progenitor cell expansion. These results support a model whereby a stem cell gene expression network driven by high ERG in human cells enhances the expansion of the progenitor pool, providing opportunity for the acquisition and propagation of mutations and the development of leukemia.

Sex-stratified and age-adjusted social gradients in tobacco in Argentina and Uruguay: evidence from the Global Adult Tobacco Survey (GATS)

OBJECTIVE

To examine social gradients in tobacco use in Argentina and Uruguay, using newly available directly comparable data sets.

METHODS

Secondary analysis of Global Adult Tobacco Survey data from Argentina (N=6645) and Uruguay (N=5581). Social gradients in current tobacco use, exposure to secondhand smoke, and cessation attempt were examined with sex-stratified and age-adjusted logistic regression.

RESULTS

Among men, there is evidence of higher odds of being a current smoker among respondents with lower levels of education, but the association is only statistically significant for respondents with less than primary education in Uruguay (OR=2.15, 95% CI 1.22 to 3.77). Similarly, women with lower levels of education have higher odds of being a current smoker in Uruguay. The association between education and exposure to secondhand smoke is broadly similar for both sexes in both countries, with generally higher odds among groups with low education, though the relationship is only statistically significant among men in Uruguay (OR=1.77, 95% CI 1.08 to 2.92). In both countries, respondents with lower levels of education in general have higher odds of having attempted to quit smoking in the past year, although these associations did not attain statistical significance.

CONCLUSIONS

Social gradients in tobacco use, exposure to secondhand smoke and cessation attempts are broadly similar in both countries. Efforts to evaluate the long-term effects of tobacco control efforts in these countries should monitor how policies affect national averages, and the social gradients that are embedded in aggregate data.

Sudden cardiac arrest risk in young athletes

Underlying cardiac abnormalities are the main cause of unexpected death in athletes on field. These abnormalities have been associated with a previous history of syncope, a family history of sudden cardiac arrest (SCA), cardiac murmur, a history of over-exhaustion post exercise and ventricular  tachyarrhythmia during physical activity. The timely diagnosis of susceptible athletes may assist with an appropriate management plan for these individuals, and allow for the prevention of premature death in sport. A young football player was screened for SCA risk using the fundamental components of the pre-participation examination (PPE) – essentially, a medical history, a resting and stress electrocardiogram, and an echocardiogram to support clinical findings. The case is submitted with consideration of the applicable literature to accentuate the importance of using PPE to prevent SCA in young athletes.

Sudden cardiac arrest risk in young athletes

Underlying cardiac abnormalities are the main cause of unexpected death in athletes on field. These abnormalities have been associated with a previous history of syncope, a family history of sudden cardiac arrest (SCA), cardiac murmur, a history of over-exhaustion post exercise and ventricular  tachyarrhythmia during physical activity. The timely diagnosis of susceptible athletes may assist with an appropriate management plan for these individuals, and allow for the prevention of premature death in sport. A young football player was screened for SCA risk using the fundamental components of the pre-participation examination (PPE) – essentially, a medical history, a resting and stress electrocardiogram, and an echocardiogram to support clinical findings. The case is submitted with consideration of the applicable literature to accentuate the importance of using PPE to prevent SCA in young athletes.

Economic benefit of the PHLAME wellness programme on firefighter injury

BACKGROUND

Work-related injuries and illness are prevalent and costly. Firefighting is especially hazardous and many firefighters sustain work-related injuries. Workplace health promotion programmes have shown positive return on investment (ROI). Little is known about how similar programmes would impact injury and cost among firefighters.

AIMS

To evaluate the impact of a workplace health promotion intervention on workers' compensation (WC) claims and medical costs among Oregon fire departments participating in the PHLAME (Promoting Healthy Lifestyles: Alternative Models' Effects) health promotion programme compared with Oregon fire departments not participating in PHLAME.

METHODS

Data from firefighters from four large urban fire departments in Oregon were evaluated using a retrospective quasi-experimental study design. Outcomes were (i) total annual firefighter WC claims, (ii) total annual incurred medical costs prior to and after implementation of the PHLAME firefighter worksite health promotion programme (iii) and an ROI analysis.

RESULTS

Data were obtained from 1369 firefighters (mean age of 42 years, 91% white, 93% male). WC claims (P < 0.001) and medical costs (P < 0.01) were significantly lower among PHLAME fire departments compared with Oregon fire departments not participating in the programme. Fire departments participating in the PHLAME TEAM programme demonstrated a positive ROI of 4.61-1.00 (TEAM is used to indicate the 12-session peer-led health promotion programme).

CONCLUSIONS

Fire department WC claims and medical costs were reduced after implementation of the PHLAME workplace health promotion programme. This is a low cost, team-based, peer-led, wellness programme that may provide a feasible, cost-effective means to reduce firefighter injury and illness rates.

FTS and 2-DG induce pancreatic cancer cell death and tumor shrinkage in mice

The Ras inhibitor S-trans-trans farnesylthiosalicylic acid (FTS) inhibits active Ras, which controls cell proliferation, differentiation, survival, and metabolism. FTS also inhibits HIF1α expression in cancer cells, leading to an energy crisis. The synthetic glucose analog 2-deoxy-D-glucose (2-DG), which inhibits glycolysis, is selectively directed to tumor cells that exhibit increased glucose consumption. The 2-DG enters tumor cells, where it competes with glucose for glycolytic enzymes. In cancer models, as well as in human phase 1 trials, 2-DG inhibits tumor growth without toxicity. We postulated that under normoxic conditions, tumor cells treated with FTS would be more sensitive than normal cells to 2-DG. We show here that combined treatment with FTS and 2-DG inhibited cancer cell proliferation additively, yet induced apoptotic cell death synergistically both in vitro and in vivo. The induced apoptosis was inferred from QVD-OPH inhibition, an increase in cleaved caspase 3, and loss of survivin. FTS and 2-DG when combined, but not separately, also induced an increase in fibrosis of the tumor tissue, chronic inflammation, and tumor shrinkage. Overall, these results suggest a possible new treatment of pancreatic tumors by the combined administration of FTS and 2-DG, which together induce pancreatic tumor cell death and tumor shrinkage under non-toxic conditions.

Rationale, design and methods of the HEALTHY study behavior intervention component

HEALTHY was a multi-center primary prevention trial designed to reduce risk factors for type 2 diabetes in adolescents. Seven centers each recruited six middle schools that were randomized to either intervention or control. The HEALTHY intervention integrated multiple components in nutrition, physical education, behavior change and communications and promotion. The conceptual rationale as well as the design and development of the behavior intervention component are described. Pilot study data informed the development of the behavior intervention component. Principles of social learning and health-related behavior change were incorporated. One element of the behavior intervention component was a sequence of peer-led, teacher-facilitated learning activities known as FLASH (Fun Learning Activities for Student Health). Five FLASH modules were implemented over five semesters of the HEALTHY study, with the first module delivered in the second semester of the sixth grade and the last module in the second semester of the eighth grade. Each module contained sessions that were designed to be delivered on a weekly basis to foster self-awareness, knowledge, decision-making skills and peer involvement for health behavior change. FLASH behavioral practice incorporated individual and group self-monitoring challenges for eating and activity. Another element of the behavior intervention component was the family outreach strategy for extending changes in physical activity and healthy eating beyond the school day and for supporting the student's lifestyle change choices. Family outreach strategies included the delivery of newsletters and supplemental packages with materials to promote healthy behavior in the home environment during school summer and winter holiday breaks. In conclusion, the HEALTHY behavior intervention component, when integrated with total school food and physical education environmental changes enhanced by communications and promotional campaigns, is a feasible and acceptable mechanism for delivering age-appropriate social learning for healthy eating and physical activity among an ethnically diverse group of middle school students across the United States.

Breath alcohol concentration determined with a new analyzer using free exhalation predicts almost precisely the arterial blood alcohol concentration

A new breath alcohol (ethanol) analyzer has been developed, which allows free exhalation, standardizes measured exhaled alcohol concentration to fully saturated water vapor at a body temperature of 37 degrees C (43.95 mg/L) and includes a built-in self-calibration system. We evaluated the performance of this instrument by comparing standardized alcohol concentration in freely expired breath (BrAC) with arterial (ABAC) and venous (VBAC) blood alcohol concentrations in fifteen healthy volunteers who drank 0.6 g of alcohol per kg body weight. The precision (coefficient of variation, CV) of the analyzer based on in vivo duplicate measurements in all phases of the alcohol metabolism was 1.7%. The ABAC/BrAC ratio was 2251+/-46 (mean+/-S.D.) in the post-absorptive phase and the mean bias between ABAC and BrAC x 2251 was 0.0035 g/L with 95% limits of agreement of 0.033 and -0.026. The ABAC and BrAC x 2251 were highly correlated (r=0.998, p<0.001) and the regression relationship was ABAC = 0.00045 + 1.0069 x (BrAC x 2251) indicating excellent agreement and no fixed or proportional bias. In the absorption phase, ABAC exceeded BrAC x 2251 by at most 0.04+/-0.03 g/L when tests were made at 10 min post-dosing (p<0.05). The VBAC/BrAC ratio never stabilized and varied continuously between 1834 and 3259. There was a proportional bias between VBAC and BrAC x 2251 (ABAC) in the post-absorptive phase (p<0.001). The pharmacokinetic analysis of the elimination rates of alcohol and times to zero BAC confirmed that BrAC x 2251 and ABAC agreed very well with each other, but not with VBAC (p<0.001). We conclude that this new breath analyzer using free exhalation has a high precision for in vivo testing. The BrAC reflects very accurately ABAC in the post-absorption phase and substantially well in the absorption phase and thereby reflects the concentration of alcohol reaching the brain. Our findings highlight the magnitude of arterio-venous differences in alcohol concentration and support the use of breath alcohol analyzers as a stand-alone test for medical and legal purposes.

A two-year, single-group experience with rotational atherectomy

Rotational atherectomy was introduced with a view to approaching percutaneously, cases that were suboptimal or unsuitable for conventional percutaneous transluminal coronary angioplasty (PTCA). In this article we present our findings for a period of two years starting in April 2001, when 60 procedures were performed on 54 patients. We found the procedure to be successful in B2 and C type lesions. It is our opinion that the lower burr-to-artery ratio used in our cases was significantly beneficial in decreasing immediate complications related to the procedure. Complimentary PTCA and stenting improved the angiographic end result. Using this strategy, we have achieved very acceptable clinical results.

A terminological and ontological analysis of the NCI Thesaurus

OBJECTIVE

The National Cancer Institute Thesaurus is described by its authors as "a biomedical vocabulary that provides consistent, unambiguous codes and definitions for concepts used in cancer research" and which "exhibits ontology-like properties in its construction and use". We performed a qualitative analysis of the Thesaurus in order to assess its conformity with principles of good practice in terminology and ontology design.

MATERIALS AND METHODS

We used both the on-line browsable version of the Thesaurus and its OWL-representation (version 04.08b, released on August 2, 2004), measuring each in light of the requirements put forward in relevant ISO terminology standards and in light of ontological principles advanced in the recent literature.

RESULTS

We found many mistakes and inconsistencies with respect to the term-formation principles used, the underlying knowledge representation system, and missing or inappropriately assigned verbal and formal definitions.

CONCLUSION

Version 04.08b of the NCI Thesaurus suffers from the same broad range of problems that have been observed in other biomedical terminologies. For its further development, we recommend the use of a more principled approach that allows the Thesaurus to be tested not just for internal consistency but also for its degree of correspondence to that part of reality which it is designed to represent.

Transoesophageal atrial pacing stress echocardiography in coronary artery disease: role, principles and methodology

This article reviews the physiology and methodology of transoesophageal atrial pacing stress echocardiography (TAPSE) and clarifies its place among the other stress modalities. TAPSE correlates well with myocardial perfusion stress scintigraphy and coronary angiography and is a simple and safe diagnostic option for patients with suspected or known CAD, including those with recent myocardial infarction. Furthermore, the results of TAPSE have prognostic significance in patients with uncomplicated MI. Although, it is a highly feasible and safe technique, the cardiologist should be directly involved in the procedure and the personnel must be well trained in a large number of tests, as for any other stress echocardiographic modalities.

Fetal muscle gene transfer is not enhanced by an RGD capsid modification to high-capacity adenoviral vectors

High levels of alpha(v) integrin expression by fetal muscle suggested that vector re-targeting to integrins could enhance adenoviral vector-mediated transduction, thereby increasing safety and efficacy of muscle gene transfer in utero. High-capacity adenoviral (HC-Ad) vectors modified by an Arg-Gly-Asp (RGD) peptide motif in the HI loop of the adenoviral fiber (RGD-HC-Ad) have demonstrated efficient gene transfer through binding to alpha(v) integrins. To test integrin targeting of HC-Ad vectors for fetal muscle gene transfer, we compared unmodified and RGD-modified HC-Ad vectors. In vivo, unmodified HC-Ad vector transduced fetal mouse muscle with four-fold higher efficiency compared to RGD-HC-Ad vector. Confirming that the difference was due to muscle cell autonomous factors and not mechanical barriers, transduction of primary myogenic cells isolated from murine fetal muscle in vitro demonstrated a three-fold better transduction by HC-Ad vector than by RGD-HC-Ad vector. We hypothesized that the high expression level of coxsackievirus and adenovirus receptor (CAR), demonstrated in fetal muscle cells both in vitro and in vivo, was the crucial variable influencing the relative transduction efficiencies of HC-Ad and RGD-HC-Ad vectors. To explore this further, we studied transduction by HC-Ad and RGD-HC-Ad vectors in paired cell lines that expressed alpha(v) integrins and differed only by the presence or absence of CAR expression. The results increase our understanding of factors that will be important for retargeting HC-Ad vectors to enhance gene transfer to fetal muscle.

"Low pressure" left ventricular tamponade in a patient with rheumatic mitral stenosis and HIV-related acute pericarditis

A case report of isolated left ventricular tamponade in a patient with rheumatic mitral stenosis and effusive pericarditis is presented. The haemodynamics and management of this under-diagnosed pathology is discussed.

Chronic idiopathic effusive pericarditis in a patient with 'cor pulmonale'

Chronic idiopathic pericarditis is a diagnosis of exclusion that is estimated to occur in 3.5% of primary pericardial disease. It is possible that many of these cases are secondary to unrecognised viral infections. The natural history is variable and treatment should be individualised, although chronic colchicines administration may hold promise as a newer therapeutic modality in symptomatic recurrent pericarditis. This case presentation illustrates the diagnostic and therapeutic difficulties that may arise in such patients.