Uptake and incorporation of Al, Cr, V, Zn and Mo in hematite: Competition, synergies and influence on structural properties

This study investigated multiple (di-, tri- and tetra-)incorporation of selected minor and trace elements (Al³⁺, Cr³⁺, V^3-5+, Zn²⁺, Mo⁶⁺ and As⁵⁺) into hematite. The purpose was to improve understanding of how hematite may control trace element mobility in the environment, and how physical and chemical properties of hematite are impacted by multi-element incorporation at x/Fe molar ratios of up to 10%. Simultaneous structural incorporation of Al±Cr±V±Zn into hematite was achieved, with both synergistic and antagonistic effects occurring between certain element combinations. Cr+Al had synergistic effects on their co-incorporation, while V negatively affected Al incorporation, and both V and Zn negatively affected Cr incorporation. In contrast, Mo was minimally associated with hematite, and As prevented hematite formation completely. X-ray diffraction indicated contraction and expansion of the hematite unit-cell upon substitution was related to the ionic radius of the substituting element in single-element samples, while V predominantly controlled the direction of deviation in multi-element samples. X-ray absorption near-edge structure spectroscopy indicated V was present as a mixture of V³⁺-V⁵⁺, with a higher average V oxidation state associated with multi-element samples. Results provide new insights into trace element geochemistry within hematite, and highlight the importance of multi-element studies to better understand natural and anthropogenic systems.

0358 Sleep Among Transgender and Cisgender Adolescents

Introduction

Sleep problems are germane to the majority of adolescents, but stigmatized youth may experience poorer sleep than those who have not experienced stigma. However, no prior studies have examined sleep among transgender adolescents (TGAs). Investigating these sleep disparities is critical, since low sleep duration and poor sleep quality are predictive of depressive symptoms and suicidality among adolescents, two mental health outcomes experienced disproportionately by TGAs. Using a nationwide survey of adolescents, we examined sleep duration, sleep quality, and rates of insufficient sleep among a sample of adolescents, and we compared those parameters between TGAs and cisgender adolescents (CGAs).

Methods

Adolescents (n=1784) ages 14-18 completed an anonymous survey including measures of sleep, sexual and gender identity, depressive symptoms, and demographic variables. Participants were grouped as TGA or CGA. Unadjusted associations between gender identity and sleep outcomes were examined, followed by multivariate regression models examining associations adjusted for demographics and depressive symptoms.

Results

TGAs reported sleeping fewer hours, higher odds of being a ‘poor sleeper’, and lower odds of getting the right amount of sleep and getting ‘enough sleep’ than CGAs. After adjusting for key demographic variables, TGAs were still more likely to report that they were poor sleepers and less likely to report getting enough sleep compared to CGAs. When adding depressive symptoms as a covariate, the finding that TGAs reported they got enough sleep less often than CGAs remained marginally significant.

Conclusion

Transgender adolescents reported receiving poorer sleep than cisgender adolescents. Future studies should focus on longitudinally examining the emergence of sleep problems among TGAs and CGAs, which may also serve to identify specific biopsychosocial pathways that contribute to heightened risk for sleep problems among TGAs. Sleep disparities may be a promising target for prevention and intervention programs to improve health outcomes among stigmatized youth.

Support

This study was funded by the University of Pittsburgh Central Research Development Fund through an award to Drs. Salk, Choukas-Bradley, and Thoma. Dr. Levenson was supported by grant K23HD087433. Dr. Thoma was supported by grants T32MH018951 and K01MH117142, Dr. Salk was supported by grant T32MH018269, and Dr. Hamilton was supported by grant T32HL082610.

1000 Social Media Use And Actigraphic Measures Of Sleep Timing Among High-risk Adolescents

Introduction

Social media use is a risk factor for poor sleep among adolescents. It remains unclear whether social media use before bed impacts later sleep timing or whether youth turn to social media because of sleep problems, which impacts sleep timing. No study to date has examined this relationship using prospective designs and objective sleep measures among high-risk adolescents, who may be particularly vulnerable to social media use.

Methods

As a preliminary test of this relationship, 25 adolescents and young adults in an intensive outpatient program for depression and suicidality completed baseline measures of social media use and wore actiwatches for up to three months. Social media use included: 1) minutes of use within 2 hours of going to sleep, and 2) frequency of social media use due to difficulty falling or staying asleep. To examine social media as a predictor of sleep timing over the next month, actigraphic measures of sleep timing (i.e., onset) were used in the first month after baseline.

Results

Multilevel modeling indicated that higher levels of social media use in the 2 hours before bed (mean = 46.94 minutes) predicted later sleep timing (B = .02; SE = .01; p= .003). Similarly, higher frequency of social media use due to perceived sleep problems predicted later sleep timing (B = .22; SE = .11; p= .04). Models covaried for age, gender, and prior-day depressed mood. When simultaneously entered, only minutes of social media use in the 2 hours before bed significantly predicted later sleep timing.

Conclusion

Findings suggest that the relationship between social media use and sleep timing among adolescents with depression and suicidality may be driven by both social media use before bed and media use due to sleep problems. Research assessing objective social media use and daily relationships are needed to further disentangle this relationship.

Support

Jessica L Hamilton is supported by a T32 fellowship from NHLBI (HL082610; PI: Buysse). This research is supported by grants from the American Foundation for Suicide Prevention and University of Pittsburgh Clinical and Translational Science Institute.

0976 Temporal Associations Between Sleep And Suicidality In Ultra-high Risk Adolescents And College Students During An Intensive Longitudinal Study

Introduction

Studies consistently demonstrate a link between subjective sleep disturbances and the continuum of suicidality, although this evidence primarily comes from retrospective, cross-sectional studies using limited items to assess sleep. Longitudinal assessment of well-defined and measured sleep/wake behaviors with high-risk individuals are needed to enhance the specificity of near-term suicide risk detection and render concrete targets for suicide prevention.

Methods

Participants (N=46) included ultra-high-risk adolescents (N=29 ages 12-18) and college students (N=17 ages 18-24). For up to 12 weeks, participants wore an actigraph to yield objective data on sleep/wake, and concurrently completed daily cellphone-based ratings of subjective sleep and suicidality. Generalized estimating equations were used to examine the association between sleep parameters (subjective and objective) and the odds of next-day suicidal outcomes (i.e., passive death wish [PDW], suicidal ideation, suicidal intent) controlling for age, gender, and depression severity.

Results

Significant quadratic relationships were observed between actigraphy-derived total sleep time (TST) and probability of next-day PDW (Z=3.7, p=0.0002), suicidal ideation (Z=2.1, p=0.04), and suicidal intent (Z=2.78, p=0.006), with increasing suicidality at low and high values of TST. Low sleep efficiency (<75%) was associated with increased odds of next-day PDW (OR=1.24, Z=2.07, p=0.038). Subjectively (sleep diary measures), low sleep quality (<50 on 100-point scale) was associated with increased odds of next-day suicidal ideation (OR=1.57, Z=3.42, p<0.001), and longer sleep onset latency (>20 minutes) with next-day suicidal intent (OR=3.00, Z=2.37, p=0.018).

Conclusion

Poor sleep health may signal increasing suicide risk, and are modifiable risk factors. We document a significant temporal association whereby objectively-derived short and long TST and low sleep efficiency, as well as subjective sleep quality and sleep onset latency, predicts next day’s suicidality. Further understanding of the temporal association between sleep and suicidality may hold promise to inform real-time monitoring and preventive strategies. Interventions targeting these factors may therefore help reduce suicidality in high-risk youth.

Support

American Foundation for Suicide Prevention; University of Pittsburgh Clinical and Translational Science Institute

Quantitative SPECT imaging and biodistribution point to molecular weight independent tumor uptake for some long-circulating polymer nanocarriers

Polymeric nanocarriers are promising entities for cancer diagnosis and therapy. The aim of such nanocarriers is to selectively accumulate in cancerous tissue that is difficult to visualize or treat. The passive accumulation of a nanocarrier in a tumor through extravasation is often attributed to the enhanced permeation and retention (EPR) effect and the size and shape of the nanocarrier. However, the tumor microenvironment is very heterogeneous and the intratumoral pressure is usually high, leading to different opinions about how the EPR of nanocarriers through the irregular vasculature of a tumor leads to accumulation. In order to investigate this topic, we studied methods for the determination of pharmacokinetic parameters, biodistribution and the tumor uptake of nanocarriers. More specifically, we used non-invasive quantitative Single-Photon Emission Computed Tomography/Computed Tomography (qSPECT/CT) imaging of hyperbranched polyglycerols (HPGs) to explore the specific biodistribution and tumor uptake of six model nanocarriers in Rag2m mice. We were interested to see if a distinct molecular weight (MW) of nanocarriers (HPG 25, 50, 100, 200, 300, 500 kDa) is favoured by the tumor. To trace the model nanocarriers, HPGs were covalently linked to the strong chelator desferrioxamine (DFO), and radiolabeled with the gamma emitter 67Ga (EC = 100%, E γ = 185 keV (21.4%), 300 keV (16.6%), half-life = 3.26 d). Without the need for blood collection, but instead using qSPECT/CT imaging inside the heart, the blood circulation half-lives of the 67Ga labeled HPGs were determined and increased from 9.9 ± 2.9 to 47.8 ± 7.9 hours with increasing polymer MW. Total tumor accumulation correlated positively with the circulation time of the HPGs. Comparing the tumor-to-blood ratio dynamically revealed how blood and tumor concentrations of the nanocarrier change over time and when equilibrium is reached. The time of equilibrium is size-dependent and increases with molecular weight. Furthermore, the data indicate that for larger MWs, nanocarrier uptake and retention by the tumor is size independent. Further studies are necessary to advance our understanding of the interplay between MW and nanoparticle accumulation in tumors.

Strategic planning in an academic radiation medicine program

Background

In this paper, we report on the process of strategic planning in the Radiation Medicine Program (rmp) at the Princess Margaret Cancer Centre. The rmp conducted a strategic planning exercise to ensure that program priorities reflect the current health care environment, enable nimble responses to the increasing burden of cancer, and guide program operations until 2020.

Methods

Data collection was guided by a project charter that outlined the project goal and the roles and responsibilities of all participants. The process was managed by a multidisciplinary steering committee under the guidance of an external consultant and consisted of reviewing strategic planning documents from close collaborators and institutional partners, conducting interviews with key stakeholders, deploying a program-wide survey, facilitating an anonymous and confidential e-mail feedback box, and collecting information from group deliberations.

Results

The process of strategic planning took place from December 2014 to December 2015. Mission and vision statements were developed, and core values were defined. A final document, Strategic Roadmap to 2020, was established to guide programmatic pursuits during the ensuing 5 years, and an implementation plan was developed to guide the first year of operations.

Conclusions

The strategic planning process provided an opportunity to mobilize staff talents and identify environmental opportunities, and helped to enable more effective use of resources in a rapidly changing health care environment. The process was valuable in allowing staff to consider and discuss the future, and in identifying strategic issues of the greatest importance to the program. Academic programs with similar mandates might find our report useful in guiding similar processes in their own organizations.

Pharmacologic augmentation of implant fixation in osteopenic bone

Osteoporosis presents a challenge for successful implant fixation due to an impaired healing response. Preclinical studies have consistently reported reduced osseointegration capability in trabecular bone. Although clinical studies of implant success in dentistry have not found a negative effect due to osteoporosis, low bone mass is a significant risk factor for implant migration in orthopedics. Pharmacologic treatment options that limit bone resorption or upregulate formation have been studied preclinically. While, both treatment options improve implant fixation, direct comparisons to-date have found anti-catabolic more effective than anabolic treatments for establishing implant fixation, but combination approaches are better than either treatment alone. Clinically, anti-catabolic treatments, particularly bisphosphonates have been shown to increase the longevity of implants, while limited clinical evidence on the effects of anabolic treatment exists. Preclinical experiments are needed to determine the effects of osteoporosis and subsequent treatment on the long-term maintenance of fixation and recovery after bone loss.

Quantitative on-line analysis of physiological data for lesion placement in pallidotomy

A computerized method of determining the focal point of electrical activity in the pallidum of parkinsonian patients was developed using on-line quantitative physiological data analysis. Thirty patients in a series of 70 were studied in depth. Neuronal activity was recorded from the pallidum using a semi-microelectrode. The signal is inspected visually while its average power, characteristic frequency and complexity are computed. The target locus was indicated by the highest level of global activity in the vicinity of the electrode (signal power maximum), maximal signal complexity and minimal characteristic frequency. Most often, the vertical coordinate required correction. The postoperative clinical and imaging results have indicated the effectiveness of this method.

Electrophysiological recordings in pallidotomy localized to 3D stereoscopic imaging

A quantitative on-line analysis of electrical activity in the pallidum of Parkinsonian patients has been developed to determine the focal point of lesioning. A 3D volume image system has been developed to display basal ganglia anatomy and coregister the electrophysiological data within the globus pallidus. Thirty patients undergoing 41 pallidotomies are presented. Neuronal activity from the pallidum is recorded using a semi-microelectrode. Based on this activity, lesioning is performed. Postlesion recordings are made to determine the necessity of additional lesioning. A stereoscopic 3D volume MR image system has been developed that along with on-line signal processing allows visualization of high neural activity in the pallidum and postlesion residual activity.

Comparison of 3-D stereoscopic MR imaging with pre and post lesion recording in pallidotomy

OBJECTIVES

A quantitative on-line analysis of electrical activity in the pallidum of Parkinsonian patients has been developed to determine the focal point of lesioning. Additional recordings are made after the lesioning, to assess residual neural activity. A 3-D volume stereoscopic image system is proposed to display the complex anatomy and to superimpose the electrophysiological data into this system. The purpose of this study is to understand the complex pathophysiology in real-time anatomic/image space and determine the location and effect of lesioning residual energy sites.

MATERIAL AND METHODS

Thirty patients undergoing 41 pallidotomies are presented. Neuronal activity from the pallidum is recorded using a semi-microelectrode. Based on this activity, lesioning is performed. Post-lesion recordings are made to determine the necessity of additional lesioning. 3-D volume MR images are acquired pre and postoperatively and compared for accuracy of lesion sites. A 3-D stereoscopic image system has been developed to depict basal ganglia geometry in the last 5 patients. Electrophysiological data are superimposed on this image system to show the surgeon the virtual position of the electrode tip.

RESULTS

A stereoscopic 3-D volume MR image system has been developed. This system more efficiently and accurately visualizes and records the coordinates of high neural activity in the pallidum and post lesion residual activity. Post-lesion power analysis was carried out in 30 patients. Additional lesions were indicated in 8 and different trajectories in 6.

CONCLUSION

Real-time visualization of neural recording, both pre and post-lesioning during pallidotomy, facilitates the surgeon's understanding of the spatiotemporal relationships of pathophysiological properties within the globus pallidus.

Evaluation of a semi-automated reticulocyte counting method using the Coulter STKS-2A blood cell counter

Reticulocyte counting was assessed on the Coulter STKS-2A automated blood cell counter. Using a two step procedure, blood samples were first incubated with the supravital stain new methylene blue. An acidic reagent was then added to clear the haemoglobin and any stained RNA was preserved within the cell. The cells were then analysed by measurement of volume, conductivity and light scatter (VCS). The results of 123 samples analysed on the STKS-2A were compared with those from a Toa Sysmex R-1000 reticulocyte counter. One hundred and seven samples gave no review flags and reticulocyte counts ranging from 0.5% to 22.8%, resulting in a correlation coefficient of 0.93 for the methods. Between run imprecision studies gave CVs ranging from 5.3% for a reticulocyte count of 8.7% to a CV of 16.3% for a 0.34% count. Stability studies showed insignificant changes over 72 h storage. These findings confirm that VCS technology can be adapted to provide precise and accurate routine reticulocyte analysis.

Inaccuracy of the 'derived' fibrinogen measurement

The 'derived' fibrinogen method is commonly used for the measurement of plasma fibrinogen. This method is not a direct quantitation of plasma fibrinogen, but an estimation of the fibrinogen concentration from the clotting curve of the prothrombin time on automated photo-optical coagulometers. An increasing number of laboratories are now routinely using this method to cope with increasing demands for fibrinogen testing. To study the suitability of this method for routine laboratory use a total of 58 samples, 20 healthy normals and 38 from other patient groups were tested by the 'derived' and Clauss fibrinogen methods on the ACL 300R. The results clearly demonstrated that 'derived' fibrinogen assay values were significantly higher than the Clauss measurements. The discrepancy between 'derived' and Clauss fibrinogen levels was greater in certain patient groups, e.g. patients receiving oral anticoagulants, than in normal controls. Some patients with documented hypodysfibrinogenaemia with low fibrinogen levels by Clauss assay gave normal 'derived' fibrinogen values. Although the 'derived' fibrinogen assay is rapid, economical and easily available to laboratories with suitable instruments, this study shows that it lacks standardization and is inaccurate compared with the Clauss assay.

Chloroplast Structure and Starch Grain Accumulation in Leaves That Received Different Red and Far-Red Levels during Development

An important step in understanding influence of growth environment on carbon metabolism in plants is to gain a better understanding of effects of light quality on the photosynthetic system. Electron microscopy was used to study chloroplast ultrastructure in developing and fully expanded leaves of tobacco (Nicotiana tabacum L. cv Burley 21). Brief exposures to red or far-red light at the end of each day during growth under controlled environments influenced granum size, granum number and starch grain accumulation in chloroplasts, and the concentration of sugars in leaf lamina. Far-red-treated leaves had chloroplasts with more but smaller grana than did red-treated leaves. Red light at the end of the photosynthetic period resulted in more and larger starch grains in the chloroplasts and a lower concentration of sugars in leaves. Chloroplast ultrastructure and starch grain accumulation patterns that were initiated in the expanding leaves were also evident in the fully expanded leaves that received the treatment during development. It appears that the phytochrome system in the developing leaves sensed the light environment and initiated events which influenced chloroplast development and partitioning of photosynthate to adapt the plant for better survival under those environmental conditions.

Ultrastructural investigation of various membrane configurations in Nicotiana tabacum

Lamellar and tubular inclusion bodies in the cell vacuole became more numerous as the severity of plant stunting was increased. In normal-appearing greenhouse plants, only a few of these inclusions were seen. In vacuoles of the severely stunted plants, much larger quantities of inclusion bodies were observed. In severely stunted plants, lamellar inclusions occurred that contained osmiophilic globules along the lamellar strands. These types of lamellar inclusions were also seen accumulating in the starch cavities of chloroplasts. From these observations, we postulated that a cell, with a given capacity to produce membrane material, produces membranous material in anticipation of growth. When the cell does not grow, owing to stunting, this excess of membrane material forms the large number of inclusion bodies seen in the vacuoles of stunted cells.

Arteriovenous malformation in chronic gastrointestinal bleeding

Arteriovenous malformations of the gastrointestinal tract are uncommon and treatment is problematic because routine barium contrast studies and endoscopy fail to demonstrate the lesion. Diagnosis is by selective mesenteric arteriography, demonstrating a characteristic vascular tuft and very early venous phase. Two cases of arteriovenous malformation are presented and 47 other reported cases are reviewed. Forty-five per cent were found in the cecum; 37, or 80%, involved the distal ileum, cecum ascending colon, or hepatic flexure. Seventy-five per cent of all patients fall into the 50--80 year age range. The literature reveals a recurring pattern of chronic gastrointestinal blood loss, anemia, and delay (even negative abdominal explorations) before the diagnosis is finally made. A more aggressive approach to chronic gastrointestinal bleeding is suggested through the use of selective mesenteric arteriography.

Optimizing test performance of moderately and severely mentally retarded adolescents and adults

This study provided further evidence for the validity of a learning potential assessment procedure with institutionalized moderately and severely retarded adolescents and adults. Significant positive correlations were obtained between psychometric and learning scores, attendants' and teachers' ratings of ability, and the posttraining scores on the modified Kohs Extended Learning Potential procedure. In addition, performance on this test-train-test procedure was compared with a train-within-test format for two different tasks: training embedded within the administration of the Leiter International Performance Scale and a formboard version of Raven's Coloured Progressive Matrices. The students responded equally to the two formats. Stanford-Binet IQs were least predictive of performance on the three learning potential measures and were unrelated to teachers' and attendants' ratings of ability. The implications of these data were discussed with particular attention to the potential advantages of the train-within-test model.

False broomrape: a physiological disorder caused by growth-regulator imbalance

False broomrape on tobacco (Nicotiana tabacum) can be induced by applying cytokinins to the roots, by causing an increase in the cytokinin-auxin ratio in the roots, by removing the apical and auxillary buds, or by applying extracts from tobacco with false broomrape to the roots of healthy plants. It can be prevented by treating debudded plants with auxin.