Monitoring retinal pathology and cerebral injury in sickle cell disease using spectral-domain optical coherence tomography in pediatric patients

PURPOSE

This study aimed to confirm the correlation between sickle cell disease (SCD) genotype and retinal damage identified by spectral-domain optical coherence tomography (SD-OCT), and examine a potential link between hypoxic ischemic injury in the retina and brain.

METHODS

In this prospective, observational case series, 117 patients (56 males) aged 5-20 years with SCD (36 SC, 68 SS, eight Sβ+ thalassemia, five Sβ0 thalassemia) underwent ophthalmologic examination including funduscopy and SD-OCT imaging. Comparison of SCD genotypes and association between ocular findings and cerebrovascular disease (CVD) in subjects with SS/Sβ0 genotype were investigated.

RESULTS

Visual acuity ranged from 20/20 to 20/40. On funduscopic exam, 16 of 117 (13.7%) had retinopathy; 69 of 117 (59.0%) showed inner retina thinning on SD-OCT. Patients with SS/Sβ0 showed a higher frequency of sickle cell retinopathy (SCR) change (68.5% vs. 47.2%), bilateral SCR (49.9% vs. 25.0%), and foveal involvement (15.1% vs. 0) than the SC genotype. While funduscopic findings in our cohort with SS/Sβ0 genotype showed no correlation with CVD, 20 of 21 patients with CVD had abnormal SD-OCT. Elevated reticulocyte percentage and aspartate aminotransferase are associated with SD-OCT changes and CVD.

CONCLUSIONS

SD-OCT was better than funduscopy in detecting retinal changes, higher frequency, and more extensive retinal changes in the more severe SCD genotypes SS and Sβ0 as compared with SC. The correlation between abnormal SD-OCT and CVD strongly suggests that retinal exam using SD-OCT may aid in detection and monitoring SCD-related CVD. Retinopathy may be another component of the hemolytic subphenotype of SCD.

Psychosocial Screening in Sickle Cell Disease: Validation of the Psychosocial Assessment Tool

OBJECTIVE

Families of youth with Sickle Cell Disease (SCD) can face psychosocial adversity including emotional distress, functional impairments, and sociodemographic risk factors. Systematic screening of psychosocial risk can identify families who may benefit from further assessment and evidence-based care. The Psychosocial Assessment Tool (PAT) is a brief caregiver-report screener based on the tri-level Pediatric Psychosocial Preventative Health Model (PPPHM).

METHODS

Findings are presented from the baseline assessment of a longitudinal study validating a Sickle Cell version of the PAT 2.0. Primary caregivers of 136 youth with SCD receiving care through a multidisciplinary SCD clinic in a children's hospital completed the PAT and validation measures. A subset of 25 caregivers completed the PAT a second time within 3-5 weeks.

RESULTS

Internal consistency for the total score was strong (α = .87), and for the subscales was moderate to strong (α  =  .74-.94), with the exception of the Family Structure (α  =  .38), Caregiver Beliefs (α  =  .48), and Stress Reactions (α  =  .56) subscales. Test-retest reliability was also strong (r = .86, p < .001). Moderate to strong correlations with all except two criteria measures provided validation for the total and subscale scores. Validation measures varied significantly across the three levels of the PPPHM.

CONCLUSIONS

Results provide support for the reliability and validity of the PAT in SCD. Systematic screening with the PAT can help identify families of youth with SCD at risk for psychosocial problems and potentially help connect them to appropriate services.

ESMO recommendations on predictive biomarker testing for homologous recombination deficiency and PARP inhibitor benefit in ovarian cancer

BACKGROUND

Homologous recombination repair deficiency (HRD) is a frequent feature of high-grade serous ovarian, fallopian tube and peritoneal carcinoma (HGSC) and is associated with sensitivity to PARP inhibitor (PARPi) therapy. HRD testing provides an opportunity to optimise PARPi use in HGSC but methodologies are diverse and clinical application remains controversial.

MATERIALS AND METHODS

To define best practice for HRD testing in HGSC the ESMO Translational Research and Precision Medicine Working Group launched a collaborative project that incorporated a systematic review approach. The main aims were to (i) define the term 'HRD test'; (ii) provide an overview of the biological rationale and the level of evidence supporting currently available HRD tests; (iii) provide recommendations on the clinical utility of HRD tests in clinical management of HGSC.

RESULTS

A broad range of repair genes, genomic scars, mutational signatures and functional assays are associated with a history of HRD. Currently, the clinical validity of HRD tests in ovarian cancer is best assessed, not in terms of biological HRD status per se, but in terms of PARPi benefit. Clinical trials evidence supports the use of BRCA mutation testing and two commercially available assays that also incorporate genomic instability for identifying subgroups of HGSCs that derive different magnitudes of benefit from PARPi therapy, albeit with some variation by clinical scenario. These tests can be used to inform treatment selection and scheduling but their use is limited by a failure to consistently identify a subgroup of patients who derive no benefit from PARPis in most studies. Existing tests lack negative predictive value and inadequately address the complex and dynamic nature of the HRD phenotype.

CONCLUSIONS

Currently available HRD tests are useful for predicting likely magnitude of benefit from PARPis but better biomarkers are urgently needed to better identify current homologous recombination proficiency status and stratify HGSC management.

Libraries May Teach Some Skills through Mobile Application Games

A Review of: Kaneko, K., Saito, Y., Nohara, Y., Kudo, E., & Yamada, M. (2018). Does physical activity enhance learning performance? Learning effectiveness of game-based experiential learning for university library instruction. Journal of Academic Librarianship, 44(5), 569-581. https://doi.org/10.1016/j.acalib.2018.06.002 Abstract Objective – To understand the impact of a mobile application game for library knowledge acquisition, task performance, and the process of learning. Design – The main experiment included a pretest, learning experience, post-test, and a questionnaire. One month later, a post-experiment was conducted, including a test of “declarative knowledge” and a behavioural test. Setting – Kyushu University in Fukuoka, Japan Subjects – 36 first-year undergraduate students, of which 25 were female and 11 were male. Students were divided into experimental and control groups. 32 students completed the study. Methods – In the main experiment, students responded to the same 20 question pre-test on library use, and then both groups participated in learning experiences designed to convey knowledge about using the library. The control group’s learning setting was a web-based tutorial about the library. The experimental group’s learning setting was “Library Adventures: Unveil the Hidden Mysteries!” a “game-based learning environment” developed by the researchers (Kaneko, Saito, Nohara, Kudo, & Yamada, 2015, p. 404), which required students to complete activities by physically moving through the library. For both groups, learning content related to local library procedures, like hours, arrangement of collections, and methods for locating books and articles. The game collected data that the authors analyzed using statistical methods in an attempt to validate quizzes that were embedded in the game. After finishing the learning experience, all students completed the 20-question post-test, and then responded to the Instructional Materials Motivation Survey (IMMS), a questionnaire designed to gauge learning motivation using the Attention, Relevance, Confidence, and Satisfaction (ARCS) model. One month following the main experiment, all students took a test of declarative knowledge and completed a skills test. Main Results – Experimental and control group students gained about the same level of declarative knowledge. All students lost some knowledge in the one-month gap between the main and post-experiment. Students who had learned through Library Adventure were able to borrow a journal and locate a newspaper article more effectively than the control group. In contrast, tutorial users made study room reservations more quickly than the experimental group. More significantly, the IMMS instrument demonstrated that game-based learners scored higher in attention, relevance, and satisfaction than tutorial-based learners. Experimental and control group participants demonstrated the same level of confidence. Conclusion – While inconclusive about the effectiveness of games versus tutorials for acquisition and retention of knowledge, the authors concluded that game-based instructional content may foster greater learner engagement, aiding some students in understanding how to use the library in a manner superior to web-based tutorials. Librarians and instructional designers developing game-based learning experiences for novice library users may find this research informative.

Relationship of Omega-3 fatty acids DHA and EPA with the inflammatory biomarker hs-CRP in children with sickle cell anemia

BACKGROUND

Inflammation and vaso-occlusion play key roles in Sickle Cell Disease (SCD) pathophysiology. Lipoxygenase products of the omega-3 fatty acids (O3FAs), docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids, are potent anti-inflammatory mediators modulating pain. O3FAs decrease episodes of vaso-occlusion in SCD.

METHODS

We assessed erythrocyte fatty acid composition in two major cell membrane phospholipids, phosphatidylcholine and phosphatidylethanolamine, in children with SCD HbSS-disease (n = 38) and age/race-matched HbAA-controls (n = 18). Ratio of pro-inflammatory arachidonic acid (AA) to anti-inflammatory DHA and EPA (FA-Ratio), and its relationship to hs-CRP were evaluated.

RESULTS

FA-Ratios were increased in both phosphatidylcholine and phosphatidylethanolamine in HbSS compared to controls. Correlations were noted in HbSS subjects between hs-CRP and FA-Ratios (p = 0.011). FA-Ratios increased with age (p = 0.0007) due to an increase in pro-inflammatory AA with a concomitant decrease in anti-inflammatory DHA.

CONCLUSIONS

Findings demonstrate relative deficiencies in HbSS of the anti-inflammatory precursor fatty acids DHA and EPA, which correlates positively with hs-CRP.

Quantitative sensory testing in children with sickle cell disease: additional insights and future possibilities

Quantitative sensory testing (QST) is used in a variety of pain disorders to characterize pain and predict prognosis and response to specific therapies. In this study, we aimed to confirm results in the literature documenting altered QST thresholds in sickle cell disease (SCD) and assess the test-retest reliability of results over time. Fifty-seven SCD and 60 control subjects aged 8-20 years underwent heat and cold detection and pain threshold testing using a Medoc TSAII. Participants were tested at baseline and 3 months; SCD subjects were additionally tested at 6 months. An important facet of our study was the development and use of a novel QST modelling approach, allowing us to model all data together across modalities. We have not demonstrated significant differences in thermal thresholds between subjects with SCD and controls. Thermal thresholds were consistent over a 3- to 6-month period. Subjects on whom hydroxycarbamide (HC) was initiated shortly before or after baseline testing (new HC users) exhibited progressive decreases in thermal sensitivity from baseline to 6 months, suggesting that thermal testing may be sensitive to effective therapy to prevent vasoocclusive pain. These findings inform the use of QST as an endpoint in the evaluation of preventative pain therapies.

Researchers May Need Additional Data Curation Support

A Review of: Johnston, L. R., Carlson, J., Hudson-Vitale, C., Imker, H., Kozlowski, W., Olendorf, R., & Stewart, C. (2018). How important are data curation activities to researchers? Gaps and opportunities for academic libraries. Journal of Librarianship and Scholarly Communication, 6(1), 1-24. https://doi.org/10.7710/2162-3309.2198 Abstract Objective – To identify the data curation activities most valued by researchers at universities. Design – Focus group and survey instrument. Setting – Six R1: Doctoral Universities in the United States of America that are part of a Data Curation Network (DCN) project to design a shared data curation service. Subjects – 91 researchers, librarians, and support staff. Methods – The authors used focus group methodology to collect data about valued data curation activities, current practices, and satisfaction with existing services or activities. Six focus groups were conducted at participants’ places of employment. Participants reviewed a list of 35 possible data curation activities, including documentation, data visualization, and rights management. A card-swapping exercise enabled subjects to rank the most important issues on a scale of 1-5, with “most important” activities becoming the subject of a facilitated discussion. In a short paper-based survey, participants also noted whether a data curation practice is in place at their institution, and their satisfaction with the practice. Main Results – Twelve data curation activities were identified as “highly rated” services that academic institutions could focus on providing to researchers. Documentation, Secure Storage, Quality Assurance, and Persistent Identifier were the data curation activities that the majority of participants rated as “most important.” Participants identified the data curation practices in place at their institutions, including documentation (80%), secure storage (75%), chain of custody (64%), metadata (63%), file inventory or manifest (58%), data visualization (58%), versioning (56%), file format transformations (55%), and quality assurance (52%). Participants reported low levels of satisfaction with their institutions’ data curation activities. Conclusion – Academic libraries have an opportunity to develop or improve existing data curation services by focusing on the twelve data curation activities that researchers, staff, and librarians value but that could be implemented in a more satisfactory way. The authors conclude that their organization, the Data Curation Network, has an opportunity to improve data curation services or to offer new or expanded services.

Information Literacy and Instruction: Reference Consultations and Student Success Outcomes

Librarians have offered personal help in the form of reference for well over a century,1 increasingly using technology of one sort or another. During much of that period, reference service was often just that—a “service” where librarians would serve up information and answers to questions from users. Thanks to the proliferation of powerful technologies, however, many individuals now attempt to seek information on their own first, in a vast morass of websites, social media, apps, blogs, wikis (including Wikipedia), videos, podcasts, and more, all vying for eyeballs. When overwhelmed by the sheer amount of information available, and unable to sort through it all to find valid, reliable information, some turn to librarians for help. It is more and more common that assistance takes the form of helping people learn how to learn for themselves, rather than simply providing answers.

Chemotherapy for metastatic castrate-sensitive prostate cancer

BACKGROUND

The role of docetaxel chemotherapy in combination with androgen deprivation therapy for metastatic castrate-sensitive prostate cancer is emerging.

METHODS

We reviewed the results from the pivotal randomized phase III trials in this area: GETUG15, CHAARTED and STAMPEDE.

RESULTS

All three studies demonstrated a benefit in progression-free survival with the use of docetaxel. However, two of the studies demonstrated a clinically meaningful overall survival benefit (CHAARTED and STAMPEDE), whereas the GETUG15 study did not demonstrate a major benefit.

CONCLUSIONS

Docetaxel is an important option to consider for men who are fit for chemotherapy with newly diagnosed metastatic prostate cancer commencing androgen deprivation therapy.

Update on pediatric leukemia and lymphoma imaging

Together, leukemia and lymphoma account for half of all childhood malignancies. Leukemia and lymphoma arise from similar cell lines and can have overlapping imaging features; however, the clinical presentation, imaging strategies, and treatment protocols can vary substantially based on the specific subtype. Although imaging does not play a central role in staging or monitoring disease in childhood leukemia, findings on imaging may be the first indication of the diagnosis. Advanced imaging, especially positron emission tomography/computed tomography, has moved to the forefront of staging and treatment response evaluation in Hodgkin's disease and non-Hodgkin's lymphoma. Imaging also plays a key role in evaluating the myriad of treatment complications that are commonly seen with chemotherapy and associated neutropenia. Future efforts will be largely focused on decreasing radiation exposure to these children, utilizing reduced or radiation-free modalities, such as positron emission tomography/magnetic resonance and diffusion-weighted whole-body imaging with background suppression, as well as refining surveillance imaging strategies. The purpose of this article is to briefly review the classification of pediatric leukemia and lymphoma, illustrate common imaging findings at presentation throughout the body, describe staging and therapeutic response evaluation, and show a spectrum of commonly encountered complications of treatment.

Plagiarism Curricula May Reduce Need for Punitive Plagiarism Education

Objective – To describe the development and implementation of two courses designed to help university students avoid plagiarism. Design – Quantitative and qualitative analysis. Setting – A university in the United Kingdom. Subjects – An unknown number of university students who took a Plagiarism Awareness Program (PAP) course between 2008 and 2011, and approximately 3,000 university students enrolled in a Plagiarism Avoidance for New Students (PANS) course delivered via a virtual learning environment (VLE) between October and December 2012. The authors attempted to collect rates of continued plagiarism among students who had taken plagiarism education courses. The authors also surveyed 702 university students about plagiarism in 2011. Methods – Data collected from PAP participants informed revision of the authors’ approach to plagiarism education and led to development of the second course, PANS. At the end of the course, students completed a test of their knowledge about plagiarism. Authors compared scores from students who took a course supervised by a librarian to the scores from students who took the course independently. Main Results – Students reported that many aspects of citation and attribution are challenging (p. 149). The authors discovered that 93% of students who completed the PANS course facilitated by a librarian in-person passed the final exam with a grade of 70% or higher, while 85% of students who took the same course independently, without a librarian instructor, in an online VLE scored 70% or higher (p. 155). The authors report that referrals of students who plagiarized declined significantly (p-value < 0.001) since the implementation of a plagiarism avoidance curriculum. Conclusion – As reported by the authors, first-year university students require more extensive education about plagiarism avoidance. A university plagiarism avoidance program instructed by librarians reduces the total number of students caught plagiarizing and mitigates the need for punitive plagiarism education programs. In discussing the challenges and implementation of plagiarism awareness curricula, the authors contribute to the dialogue about effective approaches to addressing this critical issue in higher education.

Various Factors May Influence High School Student Use of Public Libraries

Objective – To discover the factors that influence frequency of high school students’ usage of public libraries. Design – Structural equation modeling (SEM) using the person-in-environment (PIE) framework to test latent variables and direct and indirect relationships between variables. Setting – Public and school libraries in the United States. Subjects – Three datasets: Educational Longitudinal Study of 2002, the National Center for Education Statistics (NCES), provides data about individual students; Public Libraries Survey of 2004, then conducted by NCES, provides data about public libraries in the United States; and Summary Files 1 and 3 of U.S. Census 2000, provide neighborhood-level demographic data. Methods – Using ArcGIS, the researcher prepared and linked three datasets. Data were analyzed using factor analysis, regression, weighted least squares, and path analysis in order to test relationships between variables exposed in three large datasets. Main Results – Frequency of public library use by high school students may be influenced by several factors, including race and/or ethnicity and access to resources like school libraries, home computers, and public libraries with adequate service levels. Conclusion – Increased funding for public library spaces and resources may be warranted by the finding that high levels of public library service may increase high school students’ use of public libraries, particularly in socioeconomically disadvantaged neighborhoods.

Public Library Users are Challenged by Digital Information Preservation

A review of: Copeland, A. J. (2011). Analysis of public library users’ digital preservation practices. Journal of the American Society for Information Science and Technology, 62(7), 1288-1300. doi:10.1002/asi.21553 Objective – To discover the factors that influence digital information preservation practices and attitudes of adult public library users. Design – Mixed methodology combining matrix questionnaires, interviews, and visual mapping. Setting – Urban public library on the East Coast of the United States. Subjects – 26 adult members of a public library’s Friends group. Methods – The researcher conducted semi-structured interviews with 26 participants. All participants drew maps to indicate the types of information they value and why, and their preferences for information storage and maintenance. Qualitative data were supplemented by a matrix questionnaire on which 22 participants identified the types of digital information they maintain, and modes of storage. Main Results – Some public library users may store and organize information inconsistently, utilizing a variety of digital devices. Technical, social, and emotional context influences choices about organization, sharing of information, and short- and long-term preservation. Users reported placing a higher value on born digital information, and information that they had shared with others. Conclusion – Public librarians may have a role in facilitating growth of patron knowledge about creation, storage, preservation, and sharing of personal digital information.

Rituximab as potential therapy for paraneoplastic cerebellar degeneration in pediatric Hodgkin disease

Paraneoplastic cerebellar degeneration (PCD) is a rare neurological syndrome associated with lung cancer, breast adenocarcinoma,ovarian adenocarcinoma, and Hodgkin disease. It is rarely seen in pediatrics. We report a case of a 10-year-old boy with a 2-year prodrome that led to a diagnosis of PCD in association with stage IV Hodgkin disease. He received radiation and chemotherapy for his Hodgkin disease with resolution of his lymphoma. Based on promising data in adults on the efficacy of rituximab over other immuno suppressive agents in paraneoplastic disorders, he was treated with rituximab with marked improvement of the cerebellar syndrome.

Plant nutrient acquisition and utilisation in a high carbon dioxide world

Producing enough food to meet the needs of an increasing global population is one of the greatest challenges we currently face. The issue of food security is further complicated by impacts of elevated CO2 and climate change. In this viewpoint article, we begin to explore the impacts of elevated CO2 on two specific aspects of plant nutrition and resource allocation that have traditionally been considered separately. First, we focus on arbuscular mycorrhizas, which play a major role in plant nutrient acquisition. We then turn our attention to the allocation of resources (specifically N and C) in planta, with an emphasis on the secondary metabolites involved in plant defence against herbivores. In doing so, we seek to encourage a more integrated approach to investigation of all aspects of plant responses to eCO2.

U.s. Geological survey core drilling on the atlantic shelf

The first broad program of scientific shallow drilling on the U.S. Atlantic continental shelf has delineated rocks of Pleistocene to Late Cretaceous age, including phosphoritic Miocene strata, widespread Eocene carbonate deposits that serve as reflective seismic markers, and several regional unconformities. Two sites, off Maryland and New Jersey, showed light hydrocarbon gases having affinity to mature petroleum. Pore fluid studies showed that relatively fresh to brackish water occurs beneath much of the Atlantic continental shelf, whereas increases in salinity off Georgla and beneath the Florida-Hatteras slope suggest buried evaporitic strata. The sediment cores showed engineering properties that range from good foundation strength to a potential for severe loss of strength through interaction between sediments and man-made structures.

Variation in defence strategies in two species of the genus Beilschmiedia under differing soil nutrient and rainfall conditions

The relationships between various leaf functional traits that are important in plant growth (e.g., specific leaf area) have been investigated in recent studies; however, research in this context on plants that are highly protected by chemical defences, particularly resource-demanding nitrogen-based defence, is lacking. We collected leaves from cyanogenic (N-defended) Beilschmiedia collina B. Hyland and acyanogenic (C-defended) Beilschmiedia tooram (F. M. Bailey) B. Hyland at high- and low-soil nutrient sites in two consecutive years that varied significantly in rainfall. We then measured the relationships between chemical defence and morphological and functional leaf traits under the different environmental conditions. We found that the two species differed significantly in their resource allocation to defence as well as leaf morphology and function. The N defended species had a higher leaf nitrogen concentration, whereas the C-defended species had higher amounts of C-based chemical defences (i.e., total phenolics and condensed tannins). The C-defended species also tended to have higher force to fracture and increased leaf toughness. In B. collina, cyanogenic glycoside concentration was higher with higher rainfall, but not with higher soil nutrients. Total phenolic concentration was higher at the high soil nutrient site in B. tooram, but lower in B. collina; however, with higher rainfall an increase was found in B. tooram, while phenolics decreased in B. collina. Condensed tannin concentration decreased in both species with rainfall and nutrient availability. We conclude that chemical defence is correlated with leaf functional traits and that variation in environmental resources affects this correlation.

Infrared laser spectroscopy of the CH3–HCN radical complex stabilized in helium nanodroplets

The CH3-HCN and CD3-HCN radical complexes have been formed in helium nanodroplets by sequential pickup of a CH3 (CD3) radical and a HCN molecule and have been studied by high-resolution infrared laser spectroscopy. The complexes have a hydrogen-bonded structure with C3v symmetry, as inferred from the analysis of their rotationally resolved nu = 1 <-- 0 H-CN vibrational bands. The A rotational constants of the complexes are found to change significantly upon vibrational excitation of the C-H stretch of HCN within the complex, DeltaA = A'-A" = -0.04 cm(-1) (for CH3-HCN), whereas the B rotational constants are found to be 2.9 times smaller than that predicted by theory. The reduction in B can be attributed to the effects of helium solvation, whereas the large DeltaA is found to be a sensitive probe of the vibrational averaging dynamics of such weakly bound systems. The complex has a permanent electric dipole moment of 3.1 +/- 0.2 D, as measured by Stark spectroscopy. A vibration-vibration resonance is observed to couple the excited C-H stretching vibration of HCN within the complex to the lower-frequency C-H stretches of the methyl radical. Deuteration of the methyl radical was used to detune these levels from resonance, increasing the lifetime of the complex by a factor of 2. Ab initio calculations for the energies and molecular parameters of the stationary points on the CN+CH4 --> HCN+CH3 potential-energy surface are also presented.

Infrared laser spectroscopy of CH3⋯HF in helium nanodroplets: The exit-channel complex of the F+CH4 reaction

High-resolution infrared laser spectroscopy is used to study the CH3...HF and CD3...HF radical complexes, corresponding to the exit-channel complex in the F + CH4 --> HF + CH3 reaction. The complexes are formed in helium nanodroplets by sequential pickup of a methyl radical and a HF molecule. The rotationally resolved spectra presented here correspond to the fundamental v = 1 <-- 0 H-F vibrational band, the analysis of which reveals a complex with C(3v) symmetry. The vibrational band origin for the CH3...HF complex (3797.00 cm(-1)) is significantly redshifted from that of the HF monomer (3959.19 cm(-1)), consistent with the hydrogen-bonded structure predicted by theory [E. Ya. Misochko et al., J. Am. Chem. Soc. 117, 11997 (1995)] and suggested by previous matrix isolation experiments [M. E. Jacox, Chem. Phys. 42, 133 (1979)]. The permanent electric dipole moment of this complex is experimentally determined by Stark spectroscopy to be 2.4+/-0.3 D. The wide amplitude zero-point bending motion of this complex is revealed by the vibrational dependence of the A rotational constant. A sixfold reduction in the line broadening associated with the H-F vibrational mode is observed in going from CH3...HF to CD3...HF. The results suggest that fast relaxation in the former case results from near-resonant intermolecular vibration-vibration (V-V) energy transfer. Ab initio calculations are also reported (at the MP2 level) for the various stationary points on the F + CH4 surface, including geometry optimizations and vibrational frequency calculations for CH3...HF.

Finite-temperature quasicontinuum: molecular dynamics without all the atoms

Using a combination of statistical mechanics and finite-element interpolation, we develop a coarse-grained (CG) alternative to molecular dynamics (MD) for crystalline solids at constant temperature. The new approach is significantly more efficient than MD and generalizes earlier work on the quasicontinuum method. The method is validated by recovering equilibrium properties of single crystal Ni as a function of temperature. CG dynamical simulations of nano-indentation reveal a strong dependence on temperature of the critical stress to nucleate dislocations under the indenter.

Construction and evaluation of cDNA libraries for large-scale expressed sequence tag sequencing in wheat (Triticum aestivum L.)

A total of 37 original cDNA libraries and 9 derivative libraries enriched for rare sequences were produced from Chinese Spring wheat (Triticum aestivum L.), five other hexaploid wheat genotypes (Cheyenne, Brevor, TAM W101, BH1146, Butte 86), tetraploid durum wheat (T. turgidum L.), diploid wheat (T. monococcum L.), and two other diploid members of the grass tribe Triticeae (Aegilops speltoides Tausch and Secale cereale L.). The emphasis in the choice of plant materials for library construction was reproductive development subjected to environmental factors that ultimately affect grain quality and yield, but roots and other tissues were also included. Partial cDNA expressed sequence tags (ESTs) were examined by various measures to assess the quality of these libraries. All ESTs were processed to remove cloning system sequences and contaminants and then assembled using CAP3. Following these processing steps, this assembly yielded 101,107 sequences derived from 89,043 clones, which defined 16,740 contigs and 33,213 singletons, a total of 49,953 "unigenes." Analysis of the distribution of these unigenes among the libraries led to the conclusion that the enrichment methods were effective in reducing the most abundant unigenes and to the observation that the most diverse libraries were from tissues exposed to environmental stresses including heat, drought, salinity, or low temperature.

Rotational and vibrational dynamics of ethylene in helium nanodroplets

Rotationally resolved infrared spectra are reported for the asymmetric C-H stretching fundamental bands of C(2)H(4) in helium nanodroplets, as well as two weak combination bands. The J=2 rotor levels are strongly shifted from the energies estimated from a rigid rotor calculation and can be accounted for with two centrifugal distortion constants. The excited states of the three bands with B(3u) symmetry are strongly coupled in the gas phase and exhibit lifetimes >100 ps in helium, with the upper member of the polyad exhibiting the shortest lifetime. In contrast, the nu(9) band (B(2u) symmetry) exhibits very broad, homogeneously broadened line profiles (full width at half maximum approximately 0.5 cm(-1)) corresponding to an excited state lifetime of approximately 10 ps. This short lifetime is presumed to be due to an efficient, solvent mediated vibration-to-vibration relaxation process. In addition, the absence of transitions to the 2(21) and 2(20) rotor levels in the nu(9) band suggests they form rotational resonances with the elementary modes of helium, resulting in very short excited state lifetimes of less than 2 ps.

Multiple tautomers of cytosine identified and characterized by infrared laser spectroscopy in helium nanodroplets: probing structure using vibrational transition moment angles

Infrared laser spectroscopy in helium nanodroplets is used to identify and characterize several distinct tautomers of cytosine. The experimentally observed species correspond to the lowest-energy structures obtained from ab initio calculations, also reported here. The assignment of the infrared vibrational bands in the spectra is aided by the measurement of the corresponding vibrational transition moment angles, which are also calculated using ab initio methods. In the present study we confirm the existence of three primary tautomers and provide tentative assignments for even higher-energy forms of cytosine in helium nanodroplets.

Incorporating a public health approach in drug law: lessons from local expansion of treatment capacity and access under California's Proposition 36

A major state drug abuse initiative, California's Proposition 36 of 2000, mandated that adults convicted of drug possession be offered treatment in lieu of incarceration. While the law expanded public treatment for arrestees, the counties were given discretion in structuring their systems of care and procedures to manage clients. Using data from a study of key informants in eight counties, this article examines local planning to increase drug treatment capacity and manage clients' access to treatment. In both these planning domains, it describes the counties' strategies and concerns, reasons for their differences in approaches, and whether and how this state initiative, which explicitly incorporated treatment objectives into penal drug law, will shift the debate over drug abuse policy toward greater consideration of public health goals.

The isomers of HF–HCN formed in helium nanodroplets: Infrared spectroscopy and ab initio calculations

Binary complexes containing hydrogen cyanide and hydrogen fluoride are formed in helium nanodroplets, and studied using high-resolution infrared laser spectroscopy. Rotationally resolved spectra are reported for the H-F and C-H stretches of the linear HCN-HF complex, a system that has been thoroughly studied in the gas phase. We report the high-resolution spectra of the higher energy, bent HF-HCN isomer, which is also formed in helium. Stark spectra are reported for both isomers, providing dipole moments of these complexes. The experimental results are compared with ab initio calculations, also reported here. Spectra are reported for several ternary complexes, including (HCN)2-HF, HCN-(HF)2, HF-(HCN)2, and HF-HCN-HF.

Multiple isomers of uracil–water complexes: infrared spectroscopy in helium nanodroplets

Infrared laser spectroscopy is used to show that four structural isomers of the uracil-water binary complex are formed in helium nanodroplets. The assignment of the infrared spectra is aided by measurements of vibrational transition moment angles (VTMAs) for various vibrational modes of these complexes. The experimental results are in excellent agreement with ab initio calculations, which had previously predicated the existence of the same four isomers. The results suggest that the relative abundances of the various isomers formed in helium droplets have more to do with the widths of the valleys in the potential surface that funnel into a particular local minimum than on the associated energetics.

Development of an expressed sequence tag (EST) resource for wheat (Triticum aestivum L.): EST generation, unigene analysis, probe selection and bioinformatics for a 16,000-locus bin-delineated map

This report describes the rationale, approaches, organization, and resource development leading to a large-scale deletion bin map of the hexaploid (2n = 6x = 42) wheat genome (Triticum aestivum L.). Accompanying reports in this issue detail results from chromosome bin-mapping of expressed sequence tags (ESTs) representing genes onto the seven homoeologous chromosome groups and a global analysis of the entire mapped wheat EST data set. Among the resources developed were the first extensive public wheat EST collection (113,220 ESTs). Described are protocols for sequencing, sequence processing, EST nomenclature, and the assembly of ESTs into contigs. These contigs plus singletons (unassembled ESTs) were used for selection of distinct sequence motif unigenes. Selected ESTs were rearrayed, validated by 5' and 3' sequencing, and amplified for probing a series of wheat aneuploid and deletion stocks. Images and data for all Southern hybridizations were deposited in databases and were used by the coordinators for each of the seven homoeologous chromosome groups to validate the mapping results. Results from this project have established the foundation for future developments in wheat genomics.

Structures of HCN-Mgn (n=2–6) complexes from rotationally resolved vibrational spectroscopy andab initiotheory

High-resolution infrared laser spectroscopy has been used to determine the structures of HCN-Mgn complexes formed in helium nanodroplets. The magnesium atoms are first added to the droplets to ensure that the magnesium complexes are preformed before the HCN molecule is added. The vibrational frequencies, structures, and dipole moments of these complexes are found to vary dramatically with cluster size, illustrating the nonadditive nature of the HCN-magnesium interactions. All of the complexes discussed here have the nitrogen end of the HCN pointing towards the magnesium clusters. For Mg3, the HCN binds to the "threefold" site, yielding a symmetric top spectrum. Although the HCN-Mg4 complex also has C3v symmetry, the HCN sits "on-top" of a single magnesium atom. These structures are confirmed by both ab initio calculations and measurements of the dipole moments. Significant charge transfer is observed in the case of HCN-Mg4, indicative of charge donation from the lone pair on the nitrogen of HCN into the lowest unoccupied molecular orbital of the Mg4.

Infrared–infrared double resonance spectroscopy of cyanoacetylene in helium nanodroplets

Infrared-infrared double resonance spectroscopy is used as a probe of the vibrational dynamics of cyanoacetylene in helium droplets. The nu1 C-H stretching vibration of cyanoacetylene is excited by an infrared laser and subsequent vibrational relaxation results in the evaporation of approximately 660 helium atoms from the droplet. A second probe laser is then used to excite the same C-H stretching vibration downstream of the pump, corresponding to a time delay of approximately 175 micros. The hole burned by the pump laser is narrower than the single resonance spectrum, owing to the fact that the latter is inhomogeneously broadened by the droplet size distribution. The line width of the hole is characteristic of another broadening source that depends strongly on droplet size.

Vibrational predissociation in the HCl dimer

We present results of a combined theoretical and experimental study on the vibrational predissociation of the HCl dimer. On the theoretical side, photodissociation linewidths and product-state distributions for monomer stretch excited states with total angular momentum J=0 were computed, using the Fermi golden rule approximation. The resonances investigated include excitation of the hydrogen bond donor and acceptor stretches, as well as combinations of one of these modes with the intermolecular stretch and geared bend modes, for both even and odd permutation symmetry. Line strengths for the transitions from the J=1, K=0 ground state to excited states with J=0 were computed using quasibound states. On the experimental side, the photofragment angular distribution method was employed to obtain complete final-state distributions for the monomer stretch excited states. Three different transitions were probed, all starting from the lower tunneling component of the ground state: the (R)Q(0)(1) transition for excitation of the acceptor stretch and the (Q)R(0)(0) transition and unresolved (R)Q(0) branch for the donor stretch excitation. We find that, in contrast to the HF dimer, the excited-state alignment of the HCl dimer, resulting from excitation using a polarized laser beam, is completely lost on the time scale of the dissociation. The agreement between theory and experiment for the product-state distributions and line strengths is reasonable. The computed lifetimes are 1-2 orders of magnitude too small, which is attributed to a deficiency in the potential energy surface.

Reduced expression of NFAT-associated genes in UCB versus adult CD4+ T lymphocytes during primary stimulation

The cellular and molecular mechanisms underlying the blunted allo-responsiveness of umbilical cord blood (UCB) T cells have not been fully elucidated. Protein expression of NFATc2 (nuclear factor of activated T cells c2), a critical transcription factor necessary for up-regulation of multiple cytokines known to amplify T-cell allogeneic responses, is reduced in UCB T cells. Affymetrix oligonucleotide microarrays were used to compare gene expression of primary purified CD4+ UCB T cells to adult peripheral blood CD4+ T cells (AB) at baseline, 6, and 16 hours of primary stimulation. NFAT-regulated genes exhibited lower expression in UCB CD4+ T cells including the following: granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin 3 (IL-3), IL-4, IL-5, IL-13, IL-2 receptor alpha (IL-2Ralpha; CD25), CD40L, and macrophage inflammatory protein 1 alpha (MIP-1alpha). Transcription factors involved in the NFAT pathway including C/EBPbeta, JunB, and Fosl1 (Fra-1), as well as Th1- and Th2-related transcription factors STAT4 (signal transducers and activators of transcription 4), T-bet, and c-maf showed reduced expression in UCB compared with AB during primary stimulation. Reduced cytokine, chemokine, and receptor expression was also found in UCB. Gene array data were confirmed using RNase protection assays, flow cytometry, and quantitative multiplexed cytokine measurements. Reduced global expression of NFAT-associated genes, as well as cytokines and chemokines, in UCB CD4+ T cells may contribute to the decreased graft-versus-host disease (GVHD) observed after UCB transplantation.

Vibrational transition moment angles in isolated biomolecules: a structural tool

Infrared spectroscopy is used extensively in the study of isolated biomolecules, but it becomes less useful as it is applied to systems of increasing complexity. Even if the individual vibrational bands can be resolved spectroscopically, their assignment becomes problematic when they are more closely spaced than can be determined using ab initio methods. We describe a method that helps to alleviate this difficulty by measuring the direction of the vibrational transition moment for each vibrational band. The molecules of interest (adenine and cytosine) are cooled to 0.37 kelvin in liquid helium nanodroplets and oriented in a large dc electric field. A polarized infrared laser is then used to determine the directions of the infrared transition moments relative to the permanent dipole moment. Comparisons with ab initio calculations provide detailed structural information, including experimental evidence for nonplanarity of adenine and three tautomers of cytosine.

Coupled atomistic and discrete dislocation plasticity

A computational method for multiscale modeling of plasticity is presented wherein each dislocation is treated as either an atomistic or continuum entity within a single computational framework. The method divides space into atomistic and continuum regions that communicate across a coherent boundary, detects dislocations as they approach the boundary, and seamlessly converts them from one description to another. The method permits the study of problems that are too large for fully atomistic simulation while preserving accurate atomistic details where necessary, but is currently limited to a 2D implementation. A validation test is performed by comparing the method against full atomistic simulations for a 2D nanoindentation problem.

Reduced CTLA-4 protein and messenger RNA expression in umbilical cord blood T lymphocytes

OBJECTIVE

A favorable incidence and severity of graft-vs-host disease is observed in patients transplanted with banked, unrelated, HLA-mismatched umbilical cord blood (UCB) grafts, while the incidence of malignant relapse remains low. CTLA-4 mediates negative T-cell signaling and may contribute to the development of allogeneic tolerance. In this study, we compared protein and mRNA expression of CTLA-4 in stimulated UCB and adult peripheral blood T cells.

MATERIALS AND METHODS

T cells were isolated from UCB and adult peripheral blood and stimulated with anti-CD3 and anti-CD28 monoclonal antibodies. Cells were immunostained and analyzed by flow cytometry for both surface and intracellular expression of CTLA-4 in the presence and absence of cyclosporin A, and kinetics of CTLA-4 expression compared. CTLA-4 mRNA expression was measured using quantitative real-time polymerase chain reaction. NFAT1 protein levels were measured by Western blot analysis.

RESULTS

These studies demonstrate reduced surface and intracellular expression of CTLA-4 in stimulated UCB T cells compared to adult controls. Furthermore, reduced CTLA-4 protein expression in UCB T cells was noted to be in part transcriptionally regulated, as CTLA-4 mRNA levels also were significantly lower. Reduced CLTA-4 expression by UCB T cells followed the kinetics of delayed and reduced expression of the transcription factor NFAT1 by UCB T lymphocytes during primary stimulation. Moreover, cyclosporin A, which is known to modulate NFAT activation, reduced CTLA-4 protein expression in adult and UCB T cells.

CONCLUSION

Reduced expression of the key regulatory proteins CTLA-4 and NFAT-1 may contribute to favorable UCB T lymphocyte allogeneic responses.

Spiers Memorial Lecture. Comparative studies of cluster dynamics in the gas and condensed phases

Although an overview of the field of cluster dynamics is impossible to give in this Introductory Lecture, several important themes have emerged that can provide a backdrop for this Faraday Discussion. As a result, the first part of this paper introduces some of these themes, using results from the literature to illustrate some of the important issues. Although much of the work on clusters is being carried out in the gas phase (usually in free jet expansions and molecular beams), new approaches have recently been developed that permit the study of the same complexes in or on nanoscale clusters. In particular, recent developments in the field of superfluid helium droplet spectroscopy (SHEDS) permit high-resolution studies of atoms, molecules and clusters in this exotic quantum fluid. After introducing this new field, the author will discuss experiments from his own laboratory to illustrate some of the capabilities of the technique.

Cyclosporin A effects during primary and secondary activation of human umbilical cord blood T lymphocytes

OBJECTIVE

Cyclosporin A (CsA), effective in prophylaxis and treatment of graft-vs-host disease (GVHD) after human allogeneic transplantation, blunts T-cell responses by inhibiting nuclear factor of activated T cells-1 (NFAT1) activation. This laboratory has shown that NFAT1 protein expression is severely reduced in human UCB (umbilical cord blood) T cells. Since UCB is increasingly used as a hematopoietic stem cell source in allogeneic transplantation, it is important to determine whether CsA sensitivity in UCB differs from that of adult T cells.

METHODS

Surface flow cytometric analysis, intracellular cytokine staining, flow cytometric analysis of cell death, and thymidine incorporation were used in this study to determine T-cell activation and effector functions during primary and secondary stimulation in the presence of CsA.

RESULTS

Although we observed differential CsA sensitivity of T-cell activation marker (CD69, CD45RO, CD25) upregulation comparing UCB and adult, we did not observe any significant difference in CsA sensitivity of T-cell effector functions. Importantly, we observed reduced IFN-gamma and TNF-alpha expression in UCB T cells both in primary and secondary stimulation, as well as increased rates of activation-induced cell death (AICD).

CONCLUSION

Thus, our studies do not support the previous hypothesis that reduced GVHD observed after UCB transplantation is attributable to increased CsA sensitivity of UCB T cells. Rather, reduced UCB T-cell cytokine production and increased AICD may be important cellular mechanisms underlying these favorable rates of GVHD in UCB transplant recipients.

Quantitative detection of aromatic compounds in single aerosol particle mass spectrometry

Most laser-based aerosol mass spectrometers rely on a single ultraviolet laser to both ablate and ionize the aerosol particle. This technique produces complex and fragmented mass spectra, especially for organic compounds. The approach presented here achieves a more robust and quantitative analysis using a CO2 laser to evaporate the aerosol particle and a vacuum ultraviolet laser to ionize the vapor plume. Vacuum ultraviolet laser ionization produces little fragmentation in the mass spectra, making the identification of an aerosol particle's constituents more straightforward. An analysis of simple, three-component mixtures of aniline, benzyl alcohol, and m-nitrotoluene shows that the technique also provides a quantitative analysis for all the components of the mixture. Furthermore, the detection of predominantly parent ion signal from anthracene particles demonstrates the utility of the technique in the analysis of lower vapor pressure, solid-phase aerosols. Finally, we discuss the potential and limitations of this technique in analyzing organic atmospheric aerosols.

Probing the structure of metal cluster-adsorbate systems with high-resolution infrared spectroscopy

High-resolution infrared laser spectroscopy was used to obtain rotationally resolved infrared spectra of adsorbate-metal complexes. The method involves forming the bare metal clusters in helium nanodroplets and then adding a molecular adsorbate (HCN) and recording the infrared spectrum associated with the C-H stretching vibration. Rotationally resolved spectra were obtained for HCN-Mg(n) (n = 1 to 4). The results suggest a qualitative change in the adsorbate-metal cluster bonding with cluster size.