Towards building a trustworthy pipeline integrating Neuroscience Gateway and Open Science Chain

When the scientific dataset evolves or is reused in workflows creating derived datasets, the integrity of the dataset with its metadata information, including provenance, needs to be securely preserved while providing assurances that they are not accidentally or maliciously altered during the process. Providing a secure method to efficiently share and verify the data as well as metadata is essential for the reuse of the scientific data. The National Science Foundation (NSF) funded Open Science Chain (OSC) utilizes consortium blockchain to provide a cyberinfrastructure solution to maintain integrity of the provenance metadata for published datasets and provides a way to perform independent verification of the dataset while promoting reuse and reproducibility. The NSF- and National Institutes of Health (NIH)-funded Neuroscience Gateway (NSG) provides a freely available web portal that allows neuroscience researchers to execute computational data analysis pipeline on high performance computing resources. Combined, the OSC and NSG platforms form an efficient, integrated framework to automatically and securely preserve and verify the integrity of the artifacts used in research workflows while using the NSG platform. This paper presents the results of the first study that integrates OSC-NSG frameworks to track the provenance of neurophysiological signal data analysis to study brain network dynamics using the Neuro-Integrative Connectivity tool, which is deployed in the NSG platform. Database URL: https://www.opensciencechain.org.

Optimum pinhole size determination in pinhole pupilloplasty for higher-order aberrations

PURPOSE

To determine optimal pinhole size (OPS) and establish a relationship with visual acuity (VA) and RMS (root mean square) values in cases with higher-order aberrations (HOAs) undergoing pinhole pupilloplasty (PPP).

SETTING

Private practice, India.

DESIGN

Prospective, interventional study.

METHODS

RMS value for 6-mm-diameter optical zone was determined by Scheimpflug imaging (Pentacam). Patients with RMS value >0.3 μm were included. Preoperatively, a hand-held pinhole gauge with varied apertures determined the OPS, and single-pass four-throw technique was used to perform pupilloplasty with Purkinje-1 reflex as a marker for centration. VA with OPS, correlation of RMS values with OPS and pupil size, and Strehl ratio were the main outcome measures.

RESULTS

29 eyes with HOAs were analyzed; all patients chose 1.0 or 1.5 mm as OPS. The mean preoperative and postoperative pupil size was 3.25 ± 0.81 mm and 1.8 ± 0.54 mm ( P = .000), respectively. Postoperative mean pupil size when compared with OPS denoted that 14 eyes had a difference of <0.1 mm, 8 eyes ranged from 0.2 to 0.45 mm, and 7 eyes had ≥0.6 mm (range from 0.6 to 1.8 mm) difference from OPS. Eyes with higher RMS values needed smaller pupil gauge to achieve better VA. Preoperatively, vision with OPS correlated well with preoperative 6-mm RMS HOAs ( r = 0.728; P = .00). Postoperative UDVA correlated well with VA measured with OPS ( r = 0.847; P = .00). The preoperative and postoperative mean Strehl ratio was 0.109 ± 0.07 and 0.195 ± 0.11 ( P = .001), respectively.

CONCLUSIONS

Higher RMS values required a smaller pupil to achieve optimum VA. PPP can help achieve pinhole size in accordance with patient's optimum pinhole requirement.

Phacoemulsification, pinhole pupilloplasty, and pre-Descemet's endothelial keratoplasty for keratoconus with Fuchs' endothelial dystrophy

The comorbidity of keratoconus with Fuchs' endothelial dystrophy with cataract is a rare clinical combination. We present an amalgamation of surgical techniques to manage the above clinical conditions and its complications in single setting. The modified triple procedure, namely, the phacoemulsification, pinhole pupilloplasty, and pre-Descemet's endothelial keratoplasty (PDEK) in the order of description is followed in single sitting. Lens removal by phacoemulsification, correction of irregular astigmatism by pinhole pupilloplasty (pinhole optics), and exchanging the endothelial layer for PDEK forms the main segments of the triple procedure. This combination of techniques may decrease the risk of multiple surgeries and its related complications. Moreover, it will allow the patient for faster visual rehabilitation by improving the uncorrected visual acuity and visual quality.

Pinhole Pupilloplasty for Higher Order Aberrations: Assessment of Visual Quality and Depth of Focus

PURPOSE

To evaluate visual quality and depth of focus under photopic and mesopic light conditions of patients treated with pinhole pupilloplasty (PPP) for corneal higher order aberrations.

METHODS

This was a prospective, noncomparative, interventional series and PPP was performed with a single-pass four-throw procedure in 14 eyes of 14 patients. After PPP, patients were analyzed with the Clinical Trial Suite machine (M & S Technologies, Inc) that offers a standardized method of recording visual quality. The luminance levels of 85 and 3 cd/m² were set for photopic and mesopic lighting conditions, respectively, and uncorrected and corrected distance visual acuity were recorded for distance (4 m), intermediate (66 cm), and near (44 cm). Low contrast acuity (LCA) at 10% and mesopic contrast sensitivity function (CSF) with glare on and off at four spatial frequencies of 1.5, 3, 6, and 12 cycles per degree (cpd) and defocus curve were assessed.

RESULTS

Under photopic and mesopic conditions, a significant difference was observed postoperatively in uncorrected and corrected distance visual acuity for distance, intermediate, and near. The defocus curve demonstrated extended depth of focus that ranged from +1.50 to -2.50 diopters and LCA at 10% demonstrated significant improvement for all cases. For mesopic CSF, a significant improvement was noted at spatial frequencies of 3 and 6 cpd with glare on. With glare off, an improvement was seen at spatial frequencies of 1.5, 3, and 6 cpd, but not at 12 cpd.

CONCLUSIONS

Early results demonstrate that PPP provides improved visual quality and extended depth of focus and can be a useful option in cases with higher order aberrations. [J Refract Surg. 2020;36(12):812-819.].

Pinhole pupilloplasty after previous radial keratotomy

The multiple radial stromal deep corneal incisions placed in radial keratotomy (RK) lead to higher-order aberrations and pose a surgical challenge to performing any further corrective procedure on the cornea because of fear of inducing an incisional dehiscence. A method to perform pinhole pupilloplasty (PPP) in the setting of previous RK is presented. Application of pinhole optics by performing PPP leads to significant improvement in image quality and helps to optimize visual potential in post-RK cases.

Dynamic tracking of Purkinje images for the comparison of pseudophakodonesis between in-the-bag and secondary fixated intraocular lenses

PURPOSE

To compare the pseudophakodonesis of in-the-bag intraocular lens (IOL) and a secondary fixated IOL by tracking the Purkinje image IV.

SETTING

Dr. Agarwal's Eye Hospital and Eye Research Centre, Chennai, India.

DESIGN

Prospective case series.

METHODS

The IOL movement was recorded via slitlamp videography (DC3), streamed in video editor (Pinnacle), and evaluated by ImageJ analysis. The positional difference of Purkinje IV in relation to the stationary image Purkinje I at 3 random timeframes was measured. Pseudophakodonesis was quantified, compared, and correlated clinically.

RESULTS

The study comprised 127 eyes that had posterior chamber IOLs (PC IOLs) (n = 50), anterior chamber IOLs (AC IOLs) (n = 20), iris-claw IOLs (n = 20), glued IOLs (n = 30), and sutured scleral-fixated IOLs (n = 7). The iris-claw IOL showed significant difference in Purkinje IV at various timeframes (P = .0418) whereas others showed no significant change. On comparison of the Purkinje IV difference, there was a significant difference between the PC IOL and the iris-claw IOL (P = .0001), the glued IOL and the iris-claw IOL (P = .0020), and the AC IOL and the iris-claw IOL (P = .0302). The iris-claw IOL showed significant exaggeration of the position of Purkinje IV (P = .0395) after saccade. Pseudophakodonesis seemed mild (difference < 0.5 mm) in the PC IOL (68%), glued IOL (53.3%), and AC IOL (50%); moderate in the scleral-fixated IOL (71.4%); and severe (≥ 1.0 mm) in the iris-claw IOL (55%).

CONCLUSION

Positional difference in Purkinje IV was highest in iris-claw IOLs and lowest in PC IOLs.

Evolutionary algorithm optimization of biological learning parameters in a biomimetic neuroprosthesis

Biomimetic simulation permits neuroscientists to better understand the complex neuronal dynamics of the brain. Embedding a biomimetic simulation in a closed-loop neuroprosthesis, which can read and write signals from the brain, will permit applications for amelioration of motor, psychiatric, and memory-related brain disorders. Biomimetic neuroprostheses require real-time adaptation to changes in the external environment, thus constituting an example of a dynamic data-driven application system. As model fidelity increases, so does the number of parameters and the complexity of finding appropriate parameter configurations. Instead of adapting synaptic weights via machine learning, we employed major biological learning methods: spike-timing dependent plasticity and reinforcement learning. We optimized the learning metaparameters using evolutionary algorithms, which were implemented in parallel and which used an island model approach to obtain sufficient speed. We employed these methods to train a cortical spiking model to utilize macaque brain activity, indicating a selected target, to drive a virtual musculoskeletal arm with realistic anatomical and biomechanical properties to reach to that target. The optimized system was able to reproduce macaque data from a comparable experimental motor task. These techniques can be used to efficiently tune the parameters of multiscale systems, linking realistic neuronal dynamics to behavior, and thus providing a useful tool for neuroscience and neuroprosthetics.

Long-term effects of nitrous oxide anaesthesia on laboratory and clinical parameters in elderly Omani patients: a randomized double-blind study

AIMS

This study examined the long-term effects of nitrous oxide anaesthesia on serum levels of cobalamin and folate, red cell folate levels and haematological parameters, and neurological status in elderly Omani patients.

METHODS

Sixty-nine consecutive patients undergoing ophthalmic surgery were randomly and double-blind assigned to nitrous oxide or propofol anaesthesia. They met the following entry criteria: age 55 years or above, no major organ failure, no clinical signs or symptoms of cobalamin or folate deficiency, mean cell volume (MCV) </= 96 fl, haematocrit (Hct) higher than 0.3 and no cobalamin and/or folate substitution therapy during the preceding months. Serum levels of cobalamin and folate, red cell folate levels, and haematological parameters were measured prior to anaesthesia and 3-5 weeks later. At that time, the patients also underwent thorough neurological examination.

RESULTS

Data of 51 patients were complete and considered for analysis. In both nitrous oxide and propofol group, the range of exposure time was comparable (+/-1 h). In the nitrous oxide group, a slight but significant decrease in haemoglobin, Hct, and red blood cell count (RBC) (P < 0.001) was observed, whereas there was a mild increase in mean cell haemoglobin (MCH) and mean cell volume (P < 0.05). In addition, there was a significant decrease in serum folate levels (P < 0.05). Hct and RBC decreased slightly in the propofol group (P < 0. 05), whereas there was a small increase in MCH. There was no difference between the two anaesthetics with regard to serum cobalamin and red cell folate levels, but there was a significant decrease in serum folate levels in the nitrous oxide group compared to those in the propofol group. Three patients with pre-existing low red cell folate levels, who were randomized to nitrous oxide anaesthesia, developed clinical symptoms of folate deficiency.

CONCLUSION

This study showed that short-term (40-80 min) nitrous oxide anaesthesia did not affect cobalamin levels but reduced serum folate levels in this elderly population. Although this reduction was clinically irrelevant, some patients with pre-existing asymptomatic folate deficiency developed nitrous oxide-induced folate deficiency.