Measuring the impact of varying denominator definitions on standardized antibiotic consumption rates: implications for antimicrobial stewardship programmes.

Objectives: To quantify the impact of varying the at-risk days definition on the overall report of at-risk days and on the calculated standardized consumption rates (SCRs) for piperacillin/tazobactam, amikacin, daptomycin and vancomycin. Methods: Data were evaluated for two system hospitals, an 894 bed academic centre and a 114 bed community hospital. Aggregate inpatient antibiotic administration and occupancy data were extracted from electronic databases at the facility-wide level. Occupancy data were reported from admission-discharge-transfer systems. At-risk days were defined as hospital days present (DP), patient days (PD), persons present (PP) and billing days (BD). Inpatient antimicrobial days of therapy (DOT) across four major antimicrobial agents were used to calculate facility-wide SCRs using each denominator and were evaluated by least-squares regression and R2 values. Results: Within the 894 bed academic hospital, the average monthly facility-wide days were 28 424, 22 198, 15 957 and 14 789 by the DP, PP, PD and BD definitions, respectively. Within the 114 bed community hospital, the average monthly facility-wide days were 5175, 3523 and 2816 by the DP, PP and PD definitions, respectively. Strong concordance was observed between facility-wide SCRs using the DP and PP definitions in both the academic (R2 = 0.99, y = 0.78x - 0.001) and community (R2 = 0.99, y = 0.68x - 0.03) centres across all four inpatient antibiotics evaluated. In an analysis of piperacillin/tazobactam SCRs, rates were over-predicted by 28%-93% at the facility-wide level across centres using alternative denominators. Conclusions: We found that data source and definitions of at-risk denominator days meaningfully impact antibiotic SCRs. Centres should carefully consider these potential sources of variation when setting consumption benchmarks and internally evaluating use.

Safe storage and effective monitoring of CO2 in depleted gas fields.

Carbon capture and storage (CCS) is vital to reduce CO(2) emissions to the atmosphere, potentially providing 20% of the needed reductions in global emissions. Research and demonstration projects are important to increase scientific understanding of CCS, and making processes and results widely available helps to reduce public concerns, which may otherwise block this technology. The Otway Project has provided verification of the underlying science of CO(2) storage in a depleted gas field, and shows that the support of all stakeholders can be earned and retained. Quantitative verification of long-term storage has been demonstrated. A direct measurement of storage efficiency has been made, confirming that CO(2) storage in depleted gas fields can be safe and effective, and that these structures could store globally significant amounts of CO(2).

A systemwide approach to validation of electronic device denominator data.

A multidisciplinary team collaborated to develop and validate a process to electronically capture patient and device denominator data at 6 hospitals in the same healthcare system. Validation was completed within 4-16 months. Manual count errors were identified as the main driver of electronic versus manual discrepancies.

Atmospheric tomography: a Bayesian inversion technique for determining the rate and location of fugitive emissions.

A Bayesian inversion technique to determine the location and strength of trace gas emissions from a point source in open air is presented. It was tested using atmospheric measurements of N(2)O and CO(2) released at known rates from a source located within an array of eight evenly spaced sampling points on a 20-m radius circle. The analysis requires knowledge of concentration enhancement downwind of the source and the normalized, three-dimensional distribution (shape) of concentration in the dispersion plume. The influence of varying background concentrations of ∼1% for N(2)O and ∼10% for CO(2) was removed by subtracting upwind concentrations from those downwind of the source to yield only concentration enhancements. Continuous measurements of turbulent wind and temperature statistics were used to model the dispersion plume. The analysis localized the source to within 0.8 m of the true position and the emission rates were determined to better than 3% accuracy. This technique will be useful in assurance monitoring for geological storage of CO(2) and for applications requiring knowledge of the location and rate of fugitive emissions.

Improved detection of atmospheric turbulence with SLODAR.

We discuss several improvements in the detection of atmospheric turbulence using SLOpe Detection And Ranging (SLODAR). Frequently, SLODAR observations have shown strong ground-layer turbulence, which is beneficial to adaptive optics. We show that current methods which neglect atmospheric propagation effects can underestimate the strength of high altitude turbulence by up to ~ 30%. We show that mirror and dome seeing turbulence can be a significant fraction of measured ground-layer turbulence, some cases up to ~ 50%. We also demonstrate a novel technique to improve the nominal height resolution, by a factor of 3, called Generalized SLODAR. This can be applied when sampling high-altitude turbulence, where the nominal height resolution is the poorest, or for resolving details in the important ground-layer.

First ayurvedic approach towards green drugs: anti cervical cancer-cell properties of Clerodendrum viscosum root extract.

The concept of Ayurvedic expert guided drug discovery and development is defined and put to test systematically for the first time in literature. Western Science has explored only ~5% of the approximately 25,000 species of higher plants for drug leads. The ancient medical science of Ayurveda has however employed a much larger spectrum of plants for clinical treatment. Clerodendrum viscosum (CV), a commonly growing weed in the Indian subcontinent has been employed by S. Nirmalananda (Ayurvedic expert) for the treatment of cervical cancer. Here we isolate and characterize a water extract fraction (Cv-AP) from the root of CV and evaluate its anticervical cancer cell bioactivity. Our results indicate that Cv-AP possesses pro-apoptotic, anti-proliferative, and anti-migratory activity in a dose-dependent fashion against cervical cancer cell lines. In contrast, primary fibroblasts (control healthy cells), when exposed to similar concentrations of this extract, fail to undergo apoptosis and remain relatively unaffected. These findings suggest that Clerodendrum viscosum (CV) is a readily available source of components with potent anti-cancer activity and selective bioactivity against cervical cancer cells. The major component in CV-AP was identified as a glycoprotein via SDS Page and Concanavalin-A binding studies. This study serves to illustrate that systematic collaboration with Ayurveda is a practical and powerful strategy in drug discovery and development.

Ray equation for a spatially variable uniaxial crystal and its use in the optical design of liquid-crystal lenses.

To be able to design optical systems (e.g., variable focus or zoom lenses) made from liquid-crystal devices, it is necessary to be able to ray trace in a birefringent medium where the angle of the optical axis is a function of position in the device. To our knowledge, the theory required to achieve this has not previously been published, and we derive a suitable algorithm and give some examples of its use.

Volume-to-creatinine clearance ratio: a pharmacokinetically based risk factor for prediction of early creatinine increase after percutaneous coronary intervention.

OBJECTIVES: This study sought to validate a pharmacokinetically derived measure of the risk of an early increase in serum creatinine after percutaneous coronary intervention (PCI). BACKGROUND: The ratio of the volume of contrast media to the creatinine clearance (V/CrCl) has been shown to correlate with the area under the curve of contrast media concentration over time. METHODS: We calculated V/CrCl in 3,179 consecutive patients undergoing PCI. An increase in serum creatinine of >0.5 mg/dl by 24 to 48 h was considered abnormal. Receiver-operator characteristic methods were used to identify the optimal sensitivity and specificity for the observed range of V/CrCl. The predictive value of V/CrCl for the risk of an early increase in creatinine was assessed using multivariable logistic regression. RESULTS: The overall incidence of an abnormal, early increase in creatinine was 1.5%. The mean and median values of V/CrCl for patients with (mean 5.2 +/- 4.4, median 4.3, interquartile range 2.7 to 6.0) and without (mean 3.0 +/- 2.0, median 2.5, interquartile range 1.7 to 3.8) an early creatinine increase were each significantly (p < 0.001) different between groups. Furthermore, there was a significant association between V/CrCl and an early increase in creatinine (overall and trend, p < 0.001). The receiver-operator characteristic curve analysis indicated that a V/CrCl ratio of 3.7 was a fair discriminator for the early creatinine increase (C-statistic 0.69). After adjusting for other known predictors of post-PCI creatinine increase, V/CrCl > or =3.7 remained significantly associated with an early abnormal increase in serum creatinine (odds ratio 3.84; 95% confidence interval 2.0 to 7.3, p < 0.001). CONCLUSIONS: A V/CrCl ratio >3.7 was a significant and independent predictor of an early abnormal increase in serum creatinine after PCI in this unselected patient population.

Internationalization of the American Journal of Roentgenology: 1980-2002.

OBJECTIVE: The objective of this study was to analyze trends in the number of articles from international authors submitted to or published by the American Journal of Roentgenology (AJR) between 1980 and 2002. MATERIALS AND METHODS: More than 5000 articles published by the AJR during three 3-year periods (1980-1982, 1990-1992, and 2000-2002) were categorized by country of residence of the corresponding author, type of article, subject matter and age of patients, organ system, and radiologic technique. Additionally, 6202 manuscripts submitted to the AJR (1991-1992 and 2001-2002) were used to calculate the acceptance rates for the two 2-year periods. RESULTS: The percentage of articles published by the AJR from international authors was 10% (158/1610) in 1980-1982, 25% (441/1788) in 1990-1992, and 37% (602/1624) in 2000-2002 (p < 0.0001). Japanese, South Korean, and German authors achieved the largest increases during the 22 years covered by our research, and Canada had the largest decrease. The increase in international articles at the AJR was accompanied by an absolute decrease in publications from authors in the United States. Nonetheless, during 2000-2002, the acceptance rate for major papers from authors in the United States was 45% and the acceptance rate for foreign authors was 31%. During 1990-1992, the acceptance rates for major papers were 33% and 27%, respectively. CONCLUSION: The contents of the AJR reflect a continually increasing number of international articles during the past two decades.

Peer review at the American Journal of Roentgenology: how reviewer and manuscript characteristics affected editorial decisions on 196 major papers.

OBJECTIVE: The objective of this study was to examine the relative influence of manuscript characteristics and peer-reviewer attributes in the assessment of manuscripts. MATERIALS AND METHODS: Over a 6-month period, all major papers submitted to the American Journal of Roentgenology (AJR) were entered into a database that recorded manuscript characteristics, demographic profiles of reviewers, and the disposition of the manuscript. Manuscript characteristics included reviewer ratings on five scales (rhetoric, structure, science, import, and overall recommendation); the subspecialty class of the paper; the primary imaging technique; and the country of origin. Demographic profiles of the reviewers included age, sex, subspecialty, years of reviewing, academic rank, and practice type. Statistical analysis included correlation analysis, ordinal logistic regression, and analysis of variance. RESULTS: A total of 445 reviews of 196 manuscripts were the work of 335 reviewers. Of the 196 submitted manuscripts, 20 (10.2%) were accepted, 106 (54.1%) were rejected, and 70 (35.7%) were rejected with the opportunity to resubmit. Regarding manuscript characteristics, we found that the country of origin, score on the science scale, and score on the import scale were statistically significant variables for predicting the final disposition of a manuscript. Of the reviewer attributes, we found a statistically significant association between greater reviewer age and also higher academic rank with lower scores on the import scale. Reviewer concordance was higher for structure, science, and overall scores than on the rhetoric and import scores. Greater variability in the overall scoring of papers could be attributed to the reviewer than the manuscript, but both factors combined explain only 23% of the total variability. CONCLUSION: At the AJR, manuscript acceptance was most strongly associated with reviewer scoring of the science and import of a major paper and also with the country of origin. Reviewers who were older and of higher academic rank tended to discount the importance of manuscripts.