A Qualitative Study of Barriers and Facilitators to Integrating Medications for Opioid Use Disorder and HIV Preexposure Prophylaxis for Adolescents and Young Adults

BACKGROUND

The syndemic of substance use and human immunodeficiency virus (HIV) is a well-recognized global phenomenon that threatens to undermine the priorities outlined by the National Institutes of Health "Ending the HIV Epidemic" initiative. There are few published studies on preexposure prophylaxis (PrEP) for adolescents and young adults (AYAs) with opioid use disorder (OUD) despite increasing availability of biomedical prevention options and Centers for Disease Control and Prevention recommendations to offer PrEP to this group.

METHODS

Healthcare providers who previously prescribed medications for OUD (MOUDs) and/or PrEP for AYA were purposively sampled. Audio-recorded in-depth individual interviews were conducted using chart-stimulated recall to explore barriers and facilitators to integrated MOUD and HIV prevention services. Interviews were double-coded, and qualitative analysis was performed using a modified grounded theory.

RESULTS

Of 19 providers sampled, most were physicians (63%). All recommended HIV screening at varying intervals; however, few counseled on (19%) or prescribed (11%) PrEP to patients on MOUD. Barriers to PrEP prescriptions included patient-level (ie, stigma surrounding PrEP use, adherence challenges, and competing social or mental healthcare needs), provider (perception of low risk, lack of training/experience), and system-level factors (including restricted visit types). Facilitators of PrEP prescriptions included patient-initiated requests, electronic health record system reminders, and the availability of consistent support staff (ie, navigators, certified recovery specialists).

CONCLUSIONS

Our study confirms that discussions about HIV prevention and PrEP prescriptions may be rare for AYA patients receiving MOUD. Further research is needed to develop interventions that increase the integration of PrEP delivery within the context of OUD care among this key AYA population.

Sustained Effect of Clinical Decision Support for Heart Failure: A Natural Experiment Using Implementation Science

OBJECTIVES

In a randomized controlled trial, we found that applying implementation science (IS) methods and best practices in clinical decision support (CDS) design to create a locally customized, "enhanced" CDS significantly improved evidence-based prescribing of β blockers (BB) for heart failure compared with an unmodified commercially available CDS. At trial conclusion, the enhanced CDS was expanded to all sites. The purpose of this study was to evaluate the real-world sustained effect of the enhanced CDS compared with the commercial CDS.

METHODS

In this natural experiment of 28 primary care clinics, we compared clinics exposed to the commercial CDS (preperiod) to clinics exposed to the enhanced CDS (both periods). The primary effectiveness outcome was the proportion of alerts resulting in a BB prescription. Secondary outcomes included patient reach and clinician adoption (dismissals).

RESULTS

There were 367 alerts for 183 unique patients and 171 unique clinicians (pre: March 2019-August 2019; post: October 2019-March 2020). The enhanced CDS increased prescribing by 26.1% compared with the commercial (95% confidence interval [CI]: 17.0-35.1%), which is consistent with the 24% increase in the previous study. The odds of adopting the enhanced CDS was 81% compared with 29% with the commercial (odds ratio: 4.17, 95% CI: 1.96-8.85). The enhanced CDS adoption and effectiveness rates were 62 and 14% in the preperiod and 92 and 10% in the postperiod.

CONCLUSION

Applying IS methods with CDS best practices was associated with improved and sustained clinician adoption and effectiveness compared with a commercially available CDS tool.

The Various Scoring Systems in Pediatric Intensive Care Units: A Prospective Observational Study

BACKGROUND

The discrimination power of the pediatric risk of mortality (PRISM), pediatric index of mortality (PIM), sequential organ failure assessment (SOFA), and pediatric logistic organ dysfunction (PELOD) may not always be true for countries such as India due to differences in factors from those nations where these scoring systems were validated. Therefore, this study was undertaken to determine and compare severity, course of illness, and outcomes in critically ill children admitted to the pediatric intensive care unit (PICU) using different scoring systems such as PRISM 4, PIM 3, PELOD 2, and the pediatric sequential organ failure assessment (pSOFA ) score, and to analyze the clinical spectrum and demographic profile of children admitted to the PICU.

MATERIALS AND METHOD

This was a prospective, single-center, observational study conducted in the PICU of the Indira Gandhi Institute of Medical Science, Patna, India, over two years. Two hundred children in the age group of one month to 14 years admitted to the PICU were recruited into the study. Prognostic scoring systems, including PRISM4 and PIM3, were used to compare the outcome, mortality, and length of PICU stay, whereas PELODS and pSOFA were descriptive scores that assessed the multiorgan dysfunction. A correlation between the different scoring systems and the outcome was determined.

RESULTS

The majority of children (26.5%, n=53) were one to three years of age. The maximum number of patients was male (66.5%, n=133). Renal complications were the predominant admission diagnosis in 19% (n=38) of children. The mortality rate was found to be 18.5%. The mortality was most common in infants <1 year of age (n=11, 29.73%) and those of the male sex (n=22, 59.46%). A significant correlation was found between length of stay and mortality (p<0.00001). A significant positive correlation was observed between mortality and PRISM 4, PIM 3, PELOD 2, and pSOFA scores on the first day of admission (p<0.00001). The pSOFA and PELOD2 showed better discrimination power (area under the curve (AUC): 0.77 and 0.74, respectively).

CONCLUSION

The study concluded that the pSOFA and PELOD2 scores are reliable predictors of mortality in critically ill children.

To prioritize treatment options for acute acquired comitant esotropia

The management of acute acquired comitant esotropia (AACE) is controversial, and no clear guidelines exist to guide its treatment options. Therefore, the author proposes his idea that treatment options for AACE should be prioritized to achieve optimal outcomes with fewer potential complications for this type of esotropia. In this manner, treatment should be started with less invasive, muscle-sparing procedures while the patient is regularly checked for improvement in esotropia and diplopia. This is also a good scheme because the patient can go through vital neurological and ophthalmological assessments while he/she is spared from invasive interventions in the beginning.

A study of prisms and therapy in attention loss after stroke (SPATIAL): A feasibility randomised controlled trial

OBJECTIVE

Investigate feasibility and acceptability of prism adaptation training for people with inattention (spatial neglect), early after stroke, during usual care.

DESIGN

Phase II feasibility randomised controlled trial with 3:1 stratified allocation to standard occupational therapy with or without intervention, and nested process evaluation.

SETTING

Ten hospital sites providing in-patient stroke services.

PARTICIPANTS

Screened positive for inattention more than one-week post-stroke; informal carers. Occupational therapists participated in qualitative interviews.

INTERVENTION

Adjunctive prism adaptation training at the start of standard occupational therapy sessions for three weeks.

MAIN MEASURES

Feasibility measures included recruitment and retention rates, intervention fidelity and attrition. Outcomes collected at baseline, 3 weeks and 12 weeks tested measures including Nottingham Extended Activities of Daily Living Scale. Acceptability was explored through qualitative interviews and structured questions.

RESULTS

Eighty (31%) patients were eligible, 57 (71%) consented, 54 randomised (40:13, +1 exclusion) and 39 (74%) completed 12-week outcomes. Treatment fidelity was good: participants received median eight intervention sessions (IQR: 5, 12) lasting 4.7 min (IQR: 4.1, 5.0). All six serious adverse events were unrelated. There was no signal that patients allocated to intervention did better than controls. Twenty five of 35 recruited carers provided outcomes with excellent data completeness. Therapists, patients and carers found prism adaptation training acceptable.

CONCLUSIONS

It is feasible and acceptable to conduct a high-quality definitive trial of prism adaptation training within occupational therapy early after stroke in usual care setting, but difficult to justify given no sign of benefit over standard occupational therapy.

CLINICAL TRIAL REGISTRATION

https://www.isrctn.com/ Ref ISRCTN88395268.

Prism Design for Spectral Flow Cytometry

Flow cytometers are instruments used for the rapid quantitative analysis of cell suspension. Traditional flow cytometry uses multi-channel filters to detect fluorescence, whereas full-spectrum fluorescence based on dispersion detection is a more effective and accurate method. The application of various dispersion schemes in flow cytometry spectroscopy has been studied. From the perspective of modern detectors and demand for the miniaturization of flow cytometry, prism dispersion exhibits higher and more uniform light energy utilization, meaning that it is a more suitable dispersion method for small flow cytometers, such as microfluidic flow cytometers. Prism dispersion designs include the size, number, and placement of prisms. By deducing the formula of the final position of light passing through the prism and combining it with the formula of transmittance, the design criteria of the top angle and the incident angle of the prism in pursuit of the optimum transmittance and dispersion index can be obtained. Considering the case of multiple prisms, under the premise of pursuing a smaller size, the optimal design criteria for dispersion system composed of multiple prisms can be obtained. The design of prism dispersion fluorescence detection was demonstrated with a microfluidic flow cytometer, and the effectiveness of the design results was verified by microsphere experiments and practical biological experiments. This design criterion developed in this study is generally applicable to spectral flow cytometers.

A High-Sensitivity Dual-Axis Accelerometer with Two FP Cavities Assembled on Single Optical Fiber

In this paper, a dual-axis Fabry-Pérot (FP) accelerometer assembled on single optical fiber is proposed. The sensor is equipped with a special beam-splitting prism to split the light into two perpendicular directions (the X- and Y-axes); the prism surface coated with semi-permeable film and the reflective sheet on the corresponding Be-Cu vibration-sensitive spring form two sets of FP cavities of different sizes. When the Be-Cu spring with a proof mass (PM) is subjected to the vibration signal, the cavity length of the corresponding FP cavity is changed and the interference signal returns to the collimator through the original path of the prism. After bandpass filtering and demodulation, the two cavity lengths are obtained, and the acceleration measurement in dual-axis directions is completed. The resonant frequency of the proposed dual-axis fiber optic accelerometer is around 280 Hz. The results of the spectral measurements show 3.93 μm/g (g = 9.8 m/s²: gravity constant) and 4.19 μm/g for the applied acceleration along the X- and Y-axes, respectively, and the cross-axis sensitivity is below 5.1%. Within the angle range of 180°, the maximum error of measured acceleration is less than 3.77%. The proposed fiber optic dual-axis FP accelerometer has high sensitivity and strong immunity to electromagnetic interference. The size of the sensor mainly depends on the size of the prism, which is easy to reduce and mass produce. Moreover, this FP construction method has high flexibility and development potential.

Clinical Characteristics of Acquired Diplopia in Adults

PURPOSE

To describe the common causes of symptomatic strabismus and treatment required to resolve diplopia in adult patients seen by one orthoptist.

PATIENTS AND METHODS

Retrospective cross-sectional study of consecutive adult patients 18 years or older seen by one orthoptist over a 3-year period with a chief complaint of double vision.

RESULTS

Two hundred twenty-four consecutive adult patients were examined by the author. Chief complaint was double vision, followed by blurred vision, monocular diplopia, and eye strain. Past ocular histories were significant for early-childhood strabismus in 23 patients. Amblyopia was identified in five patients. Hypertension was a medical risk factor most associated with symptomatic strabismus. Cranial nerve paresis was the most common cause of the strabismus followed by benign, age-related divergence insufficiency esotropia. Prism was the most common treatment in 53% of patients followed by Bangerter foil occlusion in 44 patients (20%). Strabismus surgery was recommended in 11 patients (5%). Manifest refraction was successful in resolving symptoms of binocular diplopia in nine heterophoric patients (5%). Opaque pirate style occlusion was not used for any patient in this series.

CONCLUSIONS

Symptomatic acquired esotropia was a common type of strabismus encountered by the author and trochlear nerve paresis a common cause of symptomatic strabismus in this retrospective cross-sectional study. Press-On™ or ground-in spectacle prism of 12 prism diopters or less resolved diplopia in 124 patients (55%).

Novel use of a Franklin split lens for cycling with hemianopia

PURPOSE

Optical rehabilitation for hemianopia includes the prescription of partial aperture prismatic lenses. Fresnel lenses for this purpose have poor optical quality, while bonded lenses have poor cosmesis and can only be made in glass, creating a potential hazard. Here we present an alternative lens type, which does not reduce contrast sensitivity and which can be made in plastic materials.

METHODS

A rotated Franklin split lens was prescribed for the right eye only to provide a full aperture prismatic lens without using a Fresnel prism or bonded lenses. Using different refractive indices in each lens provided a minimal transition in thickness and an acceptable cosmetic appearance. This lens was prescribed to a 34-year-old woman with homonymous right hemianopia. Her contemporaneous comments are presented.

RESULTS

The rotated Franklin split lens provided 18Δ over the temporal edge of the lens. The wearer noticed chromatic aberration with this lens, but was able to cycle comfortably when wearing the lens without any reduction in contrast.

CONCLUSIONS

A rotated Franklin split lens can be used for the optical rehabilitation of hemianopia. In this case study, cycling was possible with this lens.

Exercise-induced diplopia: a mysterious and rare entity

A rare case of idiopathic exercise-induced diplopia was reported. A 28-year-old male experienced diplopia during and after intensive exercise. These symptoms had been present for over a year. Upon first examination, orthophoria was found. Upon examination after intensive exercise, an esophoria of 10^∆ at near and an esotropia of 4^∆ at distance was found. Neuroimaging and neurological, cardiological, and hematological evaluations were normal. A prism correction, to be used during exercise, partially resolved the diplopia. This case report aims to highlight and create general awareness about exercise-induced diplopia.

Construction of a Three-Color Prism-Based TIRF Microscope to Study the Interactions and Dynamics of Macromolecules

Simple Summary

Prism-based single-molecule total internal reflection fluorescence (prismTIRF) microscopes are excellent tools for studying macromolecular dynamics and interactions. Here, we provide an easy-to-follow guide for the design, assembly, and operation of a three-color prismTIRF microscope using commercially available components with the hope of assisting those who aim to implement TIRF imaging techniques in their laboratory.

Abstract

Single-molecule total internal reflection fluorescence (TIRF) microscopy allows for the real-time visualization of macromolecular dynamics and complex assembly. Prism-based TIRF microscopes (prismTIRF) are relatively simple to operate and can be easily modulated to fit the needs of a wide variety of experimental applications. While building a prismTIRF microscope without expert assistance can pose a significant challenge, the components needed to build a prismTIRF microscope are relatively affordable and, with some guidance, the assembly can be completed by a determined novice. Here, we provide an easy-to-follow guide for the design, assembly, and operation of a three-color prismTIRF microscope which can be utilized for the study of macromolecular complexes, including the multi-component protein–DNA complexes responsible for DNA repair, replication, and transcription. Our hope is that this article can assist laboratories that aspire to implement single-molecule TIRF techniques, and consequently expand the application of this technology.

Quantification of Cover Test Prior and Post Pyridostigmine in Diagnosis of Myasthenia Gravis

Objective: To assess the value of measuring diplopia before and after pyridostigmine intake to differentiate myasthenia gravis from sagging eye syndrome.To establish a threshold for a positive response to pyridostigmine in the diagnosis of myasthenia gravis.Methods: 15 patients with myasthenia gravis and 15 with sagging eye syndrome diplopia were evaluated. Diplopia was measured in five positions (upgaze, downgaze, right gaze, left gaze, and primary position). After baseline measurements, the patient received a single dose (60 mg) of pyridostigmine. After 60 minutes the prism measure was performed again in five positions. Horizontal deviation, vertical deviation at distance was compared before and after a single dose of pyridostigmine in each gaze. Ocular deviations were compared between the two groups to identify the threshold with the highest sensitivity and specificity.Results: Differences between pretest deviations and posttest deviations in any gaze were found to be statistically significant only in the MG group. The optimum threshold for a positive response to pyridostigmine was a reduction of 2 prism diopters in any component in any gaze. Sensitivity for the detection of myasthenia diplopia was 80.00% and specificity was 86.67%.Conclusions: Our results suggest that measuring diplopia with prisms before and after pyridostigmine administration can help to detect patients with suspected myasthenia.

Interventional Study for Improving Health Information System in Khyber Pakhtunkhwa, Pakistan

Objective To assess the improvement in the health information system in the district Nowshera by integrating the data reporting of the Expanded Program on Immunization (EPI) and Lady Health Worker (LHW) programs in the existing system. Methodology The study was conducted at district Nowshera and Swabi, Pakistan between May 2015 and May 2016 for a duration of one year. The data collection instruments used in the study were adapted from the Performance of Routine Information System Management (PRISM) tool package. The study was conducted in three phases during a period of one year. The first three months were utilized for baseline assessment. The next six months were being used for implementing the integration of the EPI and LHW, and the next three months were being used for the post-intervention evaluation. Microsoft Excel software was used to enter and analyze the data. A p < 0.05 was considered as the cut-off value for significance. Results The results indicated that the integration of data from the EPI and LHW with that of the existing Health Information System (HIS) is possible and has the potential for improving the existing system. The least significant results were produced by the use of information, which depicts that the utilization of data in decision making or policy making is still needed to be improved. Moreover, we reported a lack of enforcement and regulation by the authorities in monitoring the feedback system in the HIS. Conclusion The current study revealed significant improvements in the use of information, data quality, and behavior of staff. It is essential to properly train the team on how to operate the District Health Information System (DHIS) to gain adequate and timely data on health status and determinants. Additionally, the integration would benefit in managing the data at not only the national level but at the district level too.

Field Expansion with Multiplexing Prism Glasses Improves Pedestrian Detection for Acquired Monocular Vision

Purpose

Patients with acquired monocular vision (AMV) lose vision in the temporal crescent on the side of the blind eye. This visual field loss affects patients’ ability to detect potential hazards in the blind field. Mounting a base-in multiplexing prism (MxP) on the nasal side of the seeing eye can provide true field expansion and enable detection of potential collision hazards. We evaluated the efficacy of the MxP glasses in a virtual reality walking environment.

Methods

A three-dimensional printed clip-on MxP holder that can be adjusted for an individual user's facial parameters was developed. Virtual reality walking scenarios were designed to evaluate the effect of MxP field expansion on the detection of a pedestrian approaching from different initial bearing angles and courses. The pedestrian detection rates and response times of 10 participants with simulated AMV (normally sighted participants with one eye patched) and three patients with AMV were measured.

Results

The MxP provided true field expansion of about 25°. Participants performed significantly better with the MxP than without the MxP in the pedestrian detection task on their blind field, while their seeing field performance was not significantly different.

Conclusions

The MxP glasses for patients with AMV improved the detection of potential collision hazards in the blind field.

Translational Relevance

The MxP with an adjustable clip-on holder may help patients with AMV to decrease the risk of collision with other pedestrians.

Relation between Resonance Parameters of Surface Plasmon-Polariton Waves with Properties of the Dielectric-Metal Film-Dielectric Waveguide

The resonant excitation of the surface plasmon-polariton waves by the prism structure, where a thin silver film was coated on the prism, was studied. New analytical relations between the angular and spectral sensitivities on the change of the medium refractive index, adjacent to the metal film, were obtained. In addition, the analytical relation between the full width at the half maximum of the spectral and angular resonance dependencies were found.

Accuracy of Pediatric Risk of Mortality (PRISM) III Score in Predicting Mortality Outcomes in a Pediatric Intensive Care Unit in Karachi

Background

With the advancements in medicine and increasing access to modern technology, pediatric intensive care units (PICU) are becoming a vital part of any health care setting. PICUs play a key role in saving the life of young patients. Various scales have been designed by researchers to aid in predicting the mortality of a patient admitted in PICU. Pediatric Risk of Mortality (PRISM) and Pediatric Index of Mortality (PIM) are among the most commonly used scales. Calculating the risk of mortality enables the physicians to classify the patients and helps in identifying which patients require more urgent care and resources. 

Methods

A hospital-based prospective study was carried out at PICU in a tertiary care hospital in Karachi from December 2017 to June 2019. All patients between the age of one month and 12 years were included in our study after informed consent from parents/guardians. A standard questionnaire was used and the PRISM III score was calculated at 24 hours of admission. All necessary investigations were carried out, and all statistical analyses were carried out using SPSS v.23 (IBM, Armonk, NY).

Results

A total of 407 patients were included in our study with the majority being males (54.5%). The mean age was 27±33 months. The mean duration of stay of patients in PICU was 80.15±36.58 hours. The mortality rate in our study was 37.35 % (n=152). The need for mechanical ventilation, use of inotropic drugs, higher temperatures, and low Glasgow Coma Scale scores were associated with poor survival. It was noted that as the PRISM III score increased, the mortality rate also increased. In our study, we found that PRISM III had good predictive power in our population. The area under the curve was 0.903±0.016 (p<0.001, 95% confidence interval: 0.872-0.934).

Conclusions

PRISM III score showed excellent accuracy and predictive ability in our population. There was no significant difference in observed and expected mortality rates in our study. In a resource-limited setting, the prediction models highlight the cases where more medical attention is required and also enable the physicians to assess the prognosis of the patient so adequate measures can be taken beforehand.

High-Resolution Depth-Encoding PET Detector Module with Prismatoid Light-Guide Array

Depth-encoding detectors with single-ended readout provide a practical, cost-effective approach for constructing high-resolution and high-sensitivity PET scanners. However, the current iteration of such detectors uses a uniform glass light-guide to achieve depth encoding, resulting in nonuniform performance throughout the detector array due to suboptimal intercrystal light sharing. We introduce Prism-PET, a single-ended-readout PET detector module with a segmented light-guide composed of an array of prismatoids that introduce enhanced, deterministic light sharing. Methods: High-resolution PET detector modules were fabricated with single-ended readout of polished multicrystal lutetium yttrium orthosilicate scintillator arrays directly coupled 4-to-1 and 9-to-1 to arrays of 3 × 3 mm silicon photomultiplier pixels. Each scintillator array was coupled at the nonreadout side to a light-guide (one 4-to-1 module with a uniform glass light-guide, one 4-to-1 Prism-PET module, and one 9-to-1 Prism-PET module) to introduce intercrystal light sharing, which closely mimics the behavior of dual-ended readout, with the additional benefit of improved crystal identification. Flood histogram data were acquired using a 3-MBq ²²Na source to characterize crystal identification and energy resolution. Lead collimation was used to acquire data at specific depths to determine depth-of-interaction (DOI) resolution. Results: The flood histogram measurements showed excellent and uniform crystal separation throughout the Prism-PET modules, whereas the uniform glass light-guide module had performance degradation at the edges and corners. A DOI resolution of 5.0 mm full width at half maximum (FWHM) and an energy resolution of 13% FWHM were obtained in the uniform glass light-guide module. By comparison, the 4-to-1 coupled Prism-PET module achieved a DOI resolution of 2.5 mm FWHM and an energy resolution of 9% FWHM. Conclusion: PET scanners based on our Prism-PET modules with segmented prismatoid light-guide arrays can achieve high and uniform spatial resolution (9-to-1 coupling with ∼1-mm crystals), high sensitivity (20-mm-thick detectors and intercrystal Compton scatter recovery), good energy and timing resolutions (using polished crystals and after applying DOI correction), and compact size (depth encoding eliminates parallax error and permits smaller ring-diameter).

The Effect of Continuous Theta-Burst Transcranial Magnetic Stimulation Combined with Prism Adaptation on the Neglect Recovery in Stroke Patients

OBJECTIVES

This study was designed to investigate the effect of prism adaptation (PA) combined with continuous theta-burst transcranial magnetic stimulation (cTBS) on the neglect recovery of stroke patients with unilateral neglect.

METHODS

A total of 14 stroke patients with unilateral neglect were randomly assigned to 2 groups including an intervention group undergone PA combined with cTBS over the left intact parietal cortex and a control group. PA combined with sham cTBS was perfomed for 2 weeks in 10 daily sessions. Before and after the intervention, patients were evaluated for visuospatial neglect measured using the Star Cancellation Test (SCT), Line Bisection Task (LBT), Figure Copying Test, and Clock Drawing Task. Neurological function was evaluated using the Modified Rankin Scale (MRS).

RESULTS

Both groups (PA alone and PA+ cTBS) showed improvement in their neglected symptoms (measured by SCT, LBT, Figure Copying Test, and Clock Drawing Task), and in their disability in the neurological function (measured by MRS) (P< .05).

CONCLUSIONS

The results of the present study showed that, transcranial magnetic stimulation did not increase the effect of PA on neglect symptoms in stroke patients.

Measuring Pedestrian Collision Detection With Peripheral Field Loss and the Impact of Peripheral Prisms

Purpose

Peripheral field loss (PFL) due to retinitis pigmentosa, choroideremia, or glaucoma often results in a highly constricted residual central field, which makes it difficult for patients to avoid collision with approaching pedestrians. We developed a virtual environment to evaluate the ability of patients to detect pedestrians and judge potential collisions. We validated the system with both PFL patients and normally sighted subjects with simulated PFL. We also tested whether properly placed high-power prisms may improve pedestrian detection.

Methods

A virtual park-like open space was rendered using a driving simulator (configured for walking speeds), and pedestrians in testing scenarios appeared within and outside the residual central field. Nine normally sighted subjects and eight PFL patients performed the pedestrian detection and collision judgment tasks. The performance of the subjects with simulated PFL was further evaluated with field of view expanding prisms.

Results

The virtual system for testing pedestrian detection and collision judgment was validated. The performance of PFL patients and normally sighted subjects with simulated PFL were similar. The prisms for simulated PFL improved detection rates, reduced detection response times, and supported reasonable collision judgments in the prism-expanded field; detections and collision judgments in the residual central field were not influenced negatively by the prisms.

Conclusions

The scenarios in a virtual environment are suitable for evaluating PFL and the impact of field of view expanding devices.

Translational Relevance

This study validated an objective means to evaluate field expansion devices in reproducible near-real-life settings.

No Useful Field Expansion with Full-field Prisms

SIGNIFICANCE

Full-field prisms that fill the entire spectacle eye wire have been considered as field expansion devices for homonymous hemianopia (HH) and acquired monocular vision (AMV). Although the full-field prism is used for addressing binocular dysfunction and for prism adaptation training after brain injury as treatment for spatial hemineglect, we show that the full-field prism for field expansion does not effectively expand the visual field in either HH or AMV.

PURPOSE

Full-field prisms may shift a portion of the blind side to the residual seeing side. However, foveal fixation on an object of interest through a full-field prism requires head and/or eye rotation away from the blind side, thus negating the shift of the field toward the blind side.

METHODS

We fit meniscus and flat full-field 7Δ and 12Δ yoked prisms and conducted Goldmann perimetry in HH and AMV. We compared the perimetry results with ray tracing calculations.

RESULTS

The rated prism power was in effect at the primary position of gaze for all prisms, and the meniscus prisms maintained almost constant power at all eccentricities. To fixate on the perimetry target, the subjects needed to turn their head and/or eyes away from the blind side, which negated the field shift into the blind side. In HH, there was no difference in the perimetry results on the blind side with any of the prisms. In AMV, the lower nasal field of view was slightly shifted into the blind side with the flat prisms, but not with the meniscus prisms.

CONCLUSIONS

Full-field prisms are not an effective field expansion device owing to the inevitable fixation shift. There is potential for a small field shift with the flat full-field prism in AMV, but such lenses cannot incorporate refractive correction. Furthermore, in considering the apical scotoma, the shift provides a mere field substitution at best.

Field Expansion for Acquired Monocular Vision Using a Multiplexing Prism

SIGNIFICANCE

Acquired monocular vision (AMV) is a common visual field loss. Patients report mobility difficulties in walking due to collisions with objects or other pedestrians on the blind side.

PURPOSE

The visual field of people with AMV extends more than 90° temporally on the side of the seeing eye but is restricted to approximately 55° nasally. We developed a novel field expansion device using a multiplexing prism (MxP) that superimposes the see-through and shifted views for true field expansion without apical scotoma. We present various designs of the device that enable customized fitting and improved cosmetics.

METHODS

A partial MxP segment is attached (base-in) near the nose bridge. To avoid total internal reflection due to the high angle of incidence at nasal field end (55°), we fit the MxP with serrations facing the eye and tilt the prism base toward the nose. We calculated the width of the MxP (the apex location) needed to prevent apical scotoma and monocular diplopia. We also consider the effect of spectacle prescriptions on these settings. The results are verified perimetrically.

RESULTS

We documented the effectivity of various prototype glasses designs with perimetric measurements. With the prototypes, all patients with AMV had field-of-view expansions up to 90° nasally without any loss of seeing field.

CONCLUSIONS

The novel and properly mounted MxP in glasses has the potential for meaningful field-of-view expansion up to the size of normal binocular vision in cosmetically acceptable form.

Ultrastructure and optics of the prism-like petal epidermal cells of Eschscholzia californica (California poppy)

The petals of Eschscholzia californica (California poppy) are robust, pliable and typically coloured intensely orange or yellow owing to the presence of carotenoid pigments; they are also highly reflective at certain angles, producing a silky effect. To understand the mechanisms behind colour enhancement and reflectivity in California poppy, which represents a model species among early-divergent eudicots, we explored the development, ultrastructure, pigment composition and optical properties of the petals using light microscopy and electron microscopy combined with both spectrophotometry and goniometry. The elongated petal epidermal cells each possess a densely thickened prism-like ridge that is composed primarily of cell wall. The surface ridges strongly focus incident light onto the pigments, which are located in plastids at the cell base. Our results indicate that this highly unusual, deeply ridged surface structure not only enhances the deep colour response in this desert species, but also results in strongly angle-dependent 'silky' reflectivity that is anisotropic and mostly directional.

A Bayesian hierarchical model for demand curve analysis

Drug self-administration experiments are a frequently used approach to assess the abuse liability and reinforcing property of a compound. It has been used to assess the abuse liabilities of various substances such as psychomotor stimulants and hallucinogens, food, nicotine, and alcohol. The demand curve generated from a self-administration study describes how demand of a drug or non-drug reinforcer varies as a function of price. With the approval of the 2009 Family Smoking Prevention and Tobacco Control Act, demand curve analysis provides crucial evidence to inform the US Food and Drug Administration's policy on tobacco regulation because it produces several important quantitative measurements to assess the reinforcing strength of nicotine. The conventional approach popularly used to analyze the demand curve data is individual-specific non-linear least square regression. The non-linear least square approach sets out to minimize the residual sum of squares for each subject in the dataset; however, this one-subject-at-a-time approach does not allow for the estimation of between- and within-subject variability in a unified model framework. In this paper, we review the existing approaches to analyze the demand curve data, non-linear least square regression, and the mixed effects regression and propose a new Bayesian hierarchical model. We conduct simulation analyses to compare the performance of these three approaches and illustrate the proposed approaches in a case study of nicotine self-administration in rats. We present simulation results and discuss the benefits of using the proposed approaches.

A Bayesian hierarchical model for demand curve analysis

Drug self-administration experiments are a frequently used approach to assessing the abuse liability and reinforcing property of a compound. It has been used to assess the abuse liabilities of various substances such as psychomotor stimulants and hallucinogens, food, nicotine, and alcohol. The demand curve generated from a self-administration study describes how demand of a drug or non-drug reinforcer varies as a function of price. With the approval of the 2009 Family Smoking Prevention and Tobacco Control Act, demand curve analysis provides crucial evidence to inform the US Food and Drug Administration's policy on tobacco regulation, because it produces several important quantitative measurements to assess the reinforcing strength of nicotine. The conventional approach popularly used to analyze the demand curve data is individual-specific non-linear least square regression. The non-linear least square approach sets out to minimize the residual sum of squares for each subject in the dataset; however, this one-subject-at-a-time approach does not allow for the estimation of between- and within-subject variability in a unified model framework. In this paper, we review the existing approaches to analyze the demand curve data, non-linear least square regression, and the mixed effects regression and propose a new Bayesian hierarchical model. We conduct simulation analyses to compare the performance of these three approaches and illustrate the proposed approaches in a case study of nicotine self-administration in rats. We present simulation results and discuss the benefits of using the proposed approaches.

The Non-surgical Management of Ophthalmoplegia

Ophthalmoplegia can result from damage or dysfunction of the supranuclear eye movement pathways, the brainstem internuclear pathways, or the ocular motor nerves. Diplopia and impaired eye movements are commonly associated symptoms. The goal of non-surgical treatment is usually management of symptoms, and the primary tool used is prism. Results of recent studies in the neurorehabilitation literature have suggested that eye muscle exercise may do more than compensate for symptoms of ophthalmoplegia. They may accelerate recovery for those conditions in which recuperation is possible, and restore ocular mobility in chronic and degenerative conditions. A large, randomized, blind study is needed to investigate the efficacy of eye exercises in ophthalmoplegia.

The effect of prism on preferred retinal locus

BACKGROUND

Whether prism, especially base-up prism, affects the area of the retina used for fixation in a patient with central scotoma has been a controversial subject for 35 years. Our pilot study employed microperimetry to evaluate the effect of base-up prism on the fixation locus, or preferred retinal locus (PRL), in subjects with central scotoma.

METHODS

We used a microperimeter to assess the PRL in 13 visually impaired subjects with central scotoma under four conditions: no lens, a lens with no prism (control lens), 6^Δ base-up, and 10^Δ base-up. The PRL was measured in degrees in horizontal and vertical co-ordinates from the centre of the optic disc using graphical analysis.

RESULTS

The PRL with the control lens was not significantly different from the PRL with no lens. The preferred retinal loci with the two powers of prism were compared to the control lens and showed a superior shift in 22 of 26 cases (84.6 per cent). The amount of movement was significantly different from zero (p = 0.001 for 6^Δ and p = 0.004 for 10^Δ ). The vertical movement with the 10^Δ prism (1.73 ± 1.73 degrees) was not significantly greater (p = 0.562) than with the 6^Δ prism (1.37 ± 1.08 degrees). The shift was significantly less than the prism powers used (p < 0.001), and the amount of vertical relocation was not significantly different from the amount of horizontal movement.

CONCLUSION

In our study, base-up prism appears to shift the PRL in the direction of the prism base most of the time, but our findings do not support the use of prism as a way of predictably relocating the PRL. More study is indicated to evaluate whether such a small shift is clinically or functionally significant.

Reduction of the Influence of Laser Beam Directional Dithering in a Laser Triangulation Displacement Probe

Directional dithering of a laser beam potentially limits the detection accuracy of a laser triangulation displacement probe. A theoretical analysis indicates that the measurement accuracy will linearly decrease as the laser dithering angle increases. To suppress laser dithering, a scheme for reduction of the influence of laser beam directional dithering in a laser triangulation displacement probe, which consists of a collimated red laser, a laser beam pointing control setup, a receiver lens, and a charge-coupled device, is proposed in this paper. The laser beam pointing control setup is inserted into the source laser beam and the measured object and can separate the source laser beam into two symmetrical laser beams. Hence, at the angle at which the source laser beam dithers, the positional averages of the two laser spots are equal and opposite. Moreover, a virtual linear function method is used to maintain a stable average of the positions of the two spots on the imaging side. Experimental results indicate that with laser beam pointing control, the estimated standard deviation of the fitting error decreases from 0.3531 mm to 0.0100 mm , the repeatability accuracy can be lowered from ±7 mm to ±5 μ m , and the nonlinear error can be reduced from ±6 % FS (full scale) to ±0.16 % FS.

A 1-Diopter Vertical Prism Induces a Decrease of Head Rotation: A Pilot Investigation

Clinical studies in non-specific chronic arthralgia and back pain seem to indicate an association between vertical heterophoria (VH – latent vertical retinal misalignment) and asymmetrical head rotation. Such clinical observations suggest a link between VH and head rotation, but this was never tested. The purpose of this study was to simulate a VH in healthy subjects and examine its influence on the amplitude of active head rotation during 3D motion capture in upright stance. Subjects were asked to rotate their head three times from the straight ahead position and then to the right, back to straight ahead, to the left, and back to the straight ahead again. Three randomized conditions were run: normal viewing, with a 1-diopter prism base down on the dominant eye, or the non-dominant eye. The most important finding is that the experimental VH whichever the eye with the prism induces a significant decrease in the mean angle of head rotation compared to the normal viewing condition. This decrease was significant for rotation to the left. We suggest that the prism-induced VH modifies the reference posture and thereby affects head rotation; further studies are needed to confirm this effect and to extend to other types of dynamic activities.

Template Synthesis of Shape-Tailorable NiS2 Hollow Prisms as High-Performance Supercapacitor Materials

Uniform NiS2 hollow nanoprisms have been controllably synthesized by a facial sacrificial template method including two-step refluxed reactions. The morphology of the hollow NiS2 prisms can be easily tailored by the low cost nickel complex template. With unique hollow structure, efficient electron, and ion transport pathway as well as single crystal structure, the NiS2 hollow prisms electrode exhibits excellent pseudocapacitive performance in LiOH electrolyte. It can deliver a specific capacitance of 1725 F g(-1) at a current density of 5 A g(-1) and 1193 F g(-1) even at a current density of 40 A g(-1). Furthermore, the materials also present an amazing cycling stability, that is, the specific capacitance can increase from 1367 F g(-1) to 1680 F g(-1) after 10,000 cycles of charge-discharge at the current density of 20 A g(-1).

Evaluation and Prism Management of Divergence Insufficiency Esotropia

An esodeviation that is greater at distance than near in an adult patient requires a full sensorimotor exam to rule out any cofounding neurological conditions. Many etiologies are described in the literature to cause an esodeviation that is greater at distance than near in adult patients and some exist in conjunction with a neurological condition. However, many adult patients present to the adult strabismus clinic with no other findings on exam and have a purely benign divergence insufficiency esotropia. A review of the literature on divergence insufficiency reveals a few attempts of classifying these entities, but none have been completely accepted.Recently benign non-neurological divergence insufficiency esotropia has been described as a resulting condition due to a mechanical etiology. Currently, the literature only describes a couple of different etiologies.Regardless of the etiology, these patients are quite symptomatic and present to the adult strabismus clinic with various complaints and require a thorough examination. The primary focus of the exam is to first rule out the need for further neurological work-up, but secondly, to also determine the best treatment option for the patient. To determine the best treatment plan, a thorough evaluation, including a sensorimotor exam with proper testing, can help. Many of these patients do very well with base-out prism management; however, some have decompensated to a larger angle and prefer surgical intervention. However, the focus of this paper will be on nonsurgical prism management of patients with divergence insufficiency that is not associated with any neurological disorder.

The distinctive vertical heterophoria of dyslexics

In this study, we looked for the presence of vertical heterophoria (VH) in 42 dyslexic children (22 males and 20 females) aged 118.5±12.9 months who were compared with a control group of 22 nondyslexic children (eleven males and eleven females) aged 112±9.8 months. Dyslexics presented a low-level (always <1 prism diopter) VH combined with torsion. This oculomotor feature clearly separates the dyslexic group from the normal readers group. It is independent of the type of dyslexia. The essential feature of this VH is a lability that appears during specific stimulation of sensory receptors involved in postural regulation. This lability is demonstrated using a vertical Maddox test conducted under very specific conditions in which postural sensors are successively stimulated in a predetermined order. A quantitative variation in this VH may be seen during the Bielchowsky Head Tilt Test, which reveals hypertonia of the lower or upper oblique muscles. Vertical orthophoria can be achieved by placing low-power prisms asymmetrically within the direction of action of the superior or inferior oblique muscles. The selection of power and axis is not only guided by elements of the eye examination but also from observation of postural muscle tone. All these elements suggest that the VH could be of postural origin and somehow related to the vertical action of the oblique muscles. VH and torsion are not harmful per se. There is no statistical relationship between their level and the various parameters used to assess the reading skills of dyslexic children. VH and torsion could be a clinical marker of global proprioceptive dysfunction responsible for high-level multisensory disturbances secondary to poor spatial localization of visual and auditory information. This dysfunction might also explain the motor disorders concomitant to dyslexia.

Genetic variation of piperidine alkaloids in Pinus ponderosa: a common garden study

BACKGROUND AND AIMS

Previous measurements of conifer alkaloids have revealed significant variation attributable to many sources, environmental and genetic. The present study takes a complementary and intensive, common garden approach to examine genetic variation in Pinus ponderosa var. ponderosa alkaloid production. Additionally, this study investigates the potential trade-off between seedling growth and alkaloid production, and associations between topographic/climatic variables and alkaloid production.

METHODS

Piperidine alkaloids were quantified in foliage of 501 nursery seedlings grown from seed sources in west-central Washington, Oregon and California, roughly covering the western half of the native range of ponderosa pine. A nested mixed model was used to test differences among broad-scale regions and among families within regions. Alkaloid concentrations were regressed on seedling growth measurements to test metabolite allocation theory. Likewise, climate characteristics at the seed sources were also considered as explanatory variables.

KEY RESULTS

Quantitative variation from seedling to seedling was high, and regional variation exceeded variation among families. Regions along the western margin of the species range exhibited the highest alkaloid concentrations, while those further east had relatively low alkaloid levels. Qualitative variation in alkaloid profiles was low. All measures of seedling growth related negatively to alkaloid concentrations on a natural log scale; however, coefficients of determination were low. At best, annual height increment explained 19.4 % of the variation in ln(total alkaloids). Among the climate variables, temperature range showed a negative, linear association that explained 41.8 % of the variation.

CONCLUSIONS

Given the wide geographic scope of the seed sources and the uniformity of resources in the seedlings' environment, observed differences in alkaloid concentrations are evidence for genetic regulation of alkaloid secondary metabolism in ponderosa pine. The theoretical trade-off with seedling growth appeared to be real, however slight. The climate variables provided little evidence for adaptive alkaloid variation, especially within regions.

Eye position and cross-sensory learning both contribute to prism adaptation of auditory space

Optical prisms shift visual space, and through adaptation over time, generate a compensatory realignment of sensory-motor reference frames. In humans, prism-induced lateral shifts of visual space produce a corresponding shift in sound localization. We recently reported that sound localization shifts towards eccentric eye position, approaching approximately 40% of gaze over several minutes. Given that eye position affects sound localization directly, prism adaptation may well reflect contributions of both eye position and sensory adaptation; while the visual world is shifted by the prisms, the eyes must also shift simply to gaze ahead. To test this new concept of prism adaptation, 10 young (18-27 year) adults localized sound targets before and after 4 h of adaptation to base-right or base-left prisms that induced an 11.4 degrees shift left or right, respectively. In separate sessions subjects were exposed to: (1) natural binaural hearing; (2) diotically presented inputs devoid of meaningful spatial cues; or (3) attenuated hearing to simulate hearing loss. These preliminary results suggest that the prism adaptation of auditory space is dependent on two independent influences: (1) the effect of displaced mean eye position induced by the prisms, which occurs without cross-sensory experience; and (2) true cross-sensory learning in response to an imposed offset between auditory and visual space.

Interrater reliability of the Psychiatric Research Interview for Substance and Mental Disorders in an HIV-infected cohort: experience of the National NeuroAIDS Tissue Consortium

The interrater reliability of the Psychiatric Research Interview for Substance and Mental Disorders (PRISM) was assessed in a multicentre study. Four sites of the National NeuroAIDS Tissue Consortium performed blinded reratings of audiotaped PRISM interviews of 63 HIV-infected patients. Diagnostic modules for substance-use disorders and major depression were evaluated. Seventy-six per cent of the patient sample displayed one or more substance-use disorder diagnoses and 54% had major depression. Kappa coefficients for lifetime histories of substance abuse or dependence (cocaine, opiates, alcohol, cannabis, sedative, stimulant, hallucinogen) and major depression ranged from 0.66 to 1.00. Overall the PRISM was reliable in assessing both past and current disorders except for current cannabis disorders when patients had concomitant cannabinoid prescriptions for medical therapy. The reliability of substance-induced depression was poor to fair although there was a low prevalence of this diagnosis in our group. We conclude that the PRISM yields reliable diagnoses in a multicentre study of substance-experienced, HIV-infected individuals.