Pseudoexfoliation Glaucoma and its Systemic Association: A Clinical Study

Pseudoexfoliation [PXF] being a age related elastotic process is a well known entity among all ophthalmologists. PXF is most common form of secondary glaucoma. Objective: To study the clinical presentations and response to treatment of PXF glaucoma and also to throw light on its systemic associations. Methods: A total of 70 eyes of PXF glaucoma was considered for the study in duration of 6 months from june to November 2021 at a tertiary care center. All patients underwent detailed ophthalmic evaluation along with gonioscopy, optic disc assessment, visual fields and intraocular pressure. Based on all these , patients were graded as mild, moderate and advanced glaucoma and treated accordingly either with medical or surgical line of management. Patients were followed up for a duration of 6 months. ECG, echocardiography and dermatological evaluation of all the patients were done. Results: Mean age of 70 patients was 52.2 years and there was male preponderance .Powdery greyish white pseudoexfoliative material on pupillary margin was seen in 41 eyes[58.5%] and on anterior capsule was seen in 19 eyes[27.1%]. IOP in these 70 patients ranged between 14 to 40mmHg. Gonioscopy showed exfoliative material deposition in 14 eyes[20%] and increased pigmentation of trabecular meshwork in 44 eyes[62.85%]. Also, it revealed narrow angle( grade 1&2) in 6 eyes and open angle (grade 3&4) in rest .Visual filed changes were present in 57 of 70 eyes with PXF glaucoma. Optic disc changes in PXF glaucoma also showed variations with 17 eyes having CD ratio of<0.5,while 38 eyes had a cupping between 0.6-0.8. Eleven eyes showed advanced cupping of >0.8 while 4 eyes had glaucomatous optic atrophy.60 eyes were treated with medical line while 10 eyes were managed surgically. 4 patients had dermal nodules and diastolic dysfunction was noted in 31 patients. Conclusion: PXF confers a significantly higher risk of developing glaucoma in comparison with the general population and needs close monitering. PXF glaucoma and its systemic associations also has to be considered Keywords: PXF, pseudoexfoliative, ECG

Numerical evidence of persisting surface roughness when deposition stops

Do evolving surfaces become flat or not with time evolving when material deposition stops? As one qualitative exploration of this interesting issue, modified stochastic models for persisting roughness have been proposed by Schwartz and Edwards (2004 Phys. Rev. E 70 061602). In this work, we perform numerical simulations on the modified versions of Edwards–Wilkinson (EW) and Kardar–Parisi–Zhang (KPZ) systems when the angle of repose is introduced. Our results show that the evolving surface always presents persisting roughness during the flattening process, and sand dune-like morphology could gradually appear, even when the angle of repose is very small. Nontrivial scaling properties and differences of evolving surfaces between the modified EW and KPZ systems are also discussed.

Autonomous Robotic Feature-Based Freeform Fabrication Approach

Robotic additive manufacturing (AM) has gained much attention for its continuous material deposition capability with continuously changeable building orientations, reducing support structure volume and post-processing complexity. However, the current robotic additive process heavily relies on manual geometric reasoning that identifies additive features, related building orientations, tool approach direction, trajectory generation, and sequencing all features in a non-collision manner. In addition, multi-directional material accumulation cannot ensure the nozzle always stays above the building geometry. Thus, the collision between these two becomes a significant issue that needs to be solved. Hence, the common use of a robotic additive is hindered by the lack of fully autonomous tools based on the abovementioned issues. We present a systematic approach to the robotic AM process that can automate the abovementioned planning procedures in the aspect of collision-free. Typically, input models to robotic AM have diverse information contents and data formats, hindering the feature recognition, extraction, and relations to the robotic motion. Our proposed method integrates the collision-avoidance condition to the model decomposition step. Therefore, the decomposed volumes can be associated with additional constraints, such as accessibility, connectivity, and trajectory planning. This generates an entire workspace for the robotic additive building platform, rotatability, and additive features to determine the entire sequence and avoid potential collisions. This approach classifies the uniqueness of autonomous manufacturing on the robotic AM system to build large and complex metal components that are non-achievable through traditional one-directional AM in a computationally effective manner. This approach also paves the path in constructing an in situ monitoring and closed-loop control on robotic AM to control and enhance the build quality of the robotic metal AM process.

Co-Deposition Mechanisms of Calcium Sulfate and Calcium Carbonate Scale in Produced Water

Co-precipitation of mineral-based salts during scaling remains poorly understood and thermodynamically undefined within the water industry. This study focuses on investigating calcium carbonate and calcium sulfate mixed precipitation in scaling. Scaling is often observed in the produced water supply as a result of treatment processes. Co-precipitation results were compared with experimental results of a single salt crystallization. Several parameters were carefully monitored, including the electrical conductivity, pH value, crystal morphology and crystal form. The existence of the calcium carbonate scale in the mixed system encourages the loose calcium sulfate scale to become more tightly packed. The mixed scale was firmly adhered to the beaker, and the adhesion of the co-deposition product was located between the pure calcium sulfate scale and the pure calcium carbonate scale. The crystalline form of calcium sulfate was gypsum in both pure material deposition and mixed deposition, while the calcium carbonate scale was stable in calcite form in the pure material deposition. In the co-deposition, apart from calcite form, some calcium carbonate scale crystals had metastable vaterite form. This indicated that the presence of SO42− ions reduced the energy barrier of the calcium carbonate scale and hindered its transformation from a vaterite form to a calcite one, and the increase in HCO3− content inhibited the formation of calcium sulfate scale.

Linear Electron Beam Assisted Roll-to-Roll in-Vacuum Flexographic Patterning for Flexible Thermoelectric Generators

In this work, we investigated the use of in-line linear electron beam irradiation (LEB) surface treatment integrated into a commercially compatible roll-to-roll (R2R) processing line, as a single fluorocarbon cleaning step, following flexography oil masking used to pattern layers for devices. Thermoelectric generators (TEGs) were selected as the flexible electronic device demonstrator; a green renewable energy harvester ideal for powering wearable technologies. BiTe/BiSbTe-based flexible TEGs (f-TEGs) were fabricated using in-line oil patterned aluminium electrodes, followed by a 600 W LEB cleaning step, in which the duration was optimised. A BiTe/BiSbTe f-TEG using an oil-patterned electrode and a 15 min LEB clean (to remove oil prior to BiTe/BiSbTe deposition) showed similar Seebeck and output power (S~0.19 mV K−1 and p = 0.02 nW at ΔT = 20 K) compared to that of an oil-free reference f-TEG, demonstrating the success of using the LEB as a cleaning step to prevent any remaining oil interfering with the subsequent active material deposition. Device lifetimes were investigated, with electrode/thermoelectric interface degradation attributed to an aluminium/fluorine reaction, originating from the fluorine-rich masking oil. A BiTe/GeTe f-TEG using an oil-patterned/LEB clean, exceeded the lifetime of the comparable BiTe/BiSbTe f-TEG, highlighting the importance of deposited material reactivities with the additives from the masking oil, in this case fluorine. This work therefore demonstrates (i) full device architectures within an R2R system using vacuum flexography oil patterned electrodes; (ii) an enabling Electron beam cleansing step for removal of oil remnants; and (iii) that careful selection of masking oils is needed for the materials used when flexographic patterning during R2R.

Designed Deposition - Freeform 3D Printing for Digitally Crafted Artefacts

<p>Through the exploitation of new additive manufacturing (AM) processes, this research seeks to reinvent the designer as an informed mediator between the digitally defined and the physically expressed. Current 3D printing techniques generally construct an object layer by layer, building vertically in the z-axis. Recently developed, ‘freeform 3D printing’ is an AM method which builds through the deposition of material that solidifies upon extrusion. The result is free-standing material forms with diminished need for support material. Building in this spatial manner means that AM is no longer reliant on layer based techniques that are built from ground-up. Instead, motions can move simultaneously in the x, y and z axes. This increased freedom of motion allows the designer to disregard the requisite that solid forms need to be delineated prior to considering material deposition. Considering this in relationship to the design of artefacts, specific approaches that consider both form and material deposition concurrently allow the authorship of the method of making to be reclaimed. Bespoke computational processes work to encode material deposition with qualities that are tactile, visual and expressive of its making method. Considerations to structural, performative and aesthetic implications are assimilated from the onset rather than post-rationalised. Material deposition is crafted to become three-dimensionally informed and considerate of the integral nature of its making method and its output, exposing new design opportunities. Among other things, the research-through-design process suggests how parametric modelling could be used for mass-customisation and suggests a possible path for AM beyond prototyping, towards the manufacturing of bespoke products through an industrial design perspective. Through iterative abstract and application based experiments, Designed Deposition pursues an increasingly integrated process between the user, the designer, the digital and the physical, towards the creation of digitally crafted artefacts.</p>