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Reactive Amine Functionalized Microelectrode Arrays Provide Short-Term Benefit but Long-Term Detriment to In Vivo Recording Performance
Get PDFIntracortical microelectrode arrays (MEAs) are used for recording neural signals. However, indwelling devices result in chronic neuroinflammation, which leads to decreased recording performance through degradation of the device and surrounding tissue. Coating the MEAs with bioactive molecules is being explored to mitigate neuroinflammation. Such approaches often require an intermediate functionalization step such as (3-aminopropyl)triethoxysilane (APTES), which serves as a linker. However, the standalone effect of this intermediate step has not been previously characterized. Here, we investigated the effect of coating MEAs with APTES by comparing APTES-coated to uncoated controls in vivo and ex vivo. First, we measured water contact angles between silicon uncoated and APTES-coated substrates to verify the hydrophilic characteristics of the APTES coating. Next, we implanted MEAs in the motor cortex (M1) of Sprague−Dawley rats with uncoated or APTES-coated devices. We assessed changes in the electrochemical impedance and neural recording performance over a chronic implantation period of 16 weeks. Additionally, histology and bulk gene expression were analyzed to understand further the reactive tissue changes arising from the coating. Results showed that APTES increased the hydrophilicity of the devices and decreased electrochemical impedance at 1 kHz. APTES coatings proved detrimental to the recording performance, as shown by a constant decay up to 16 weeks postimplantation. Bulk gene analysis showed differential changes in gene expression between groups that were inconclusive with regard to the long-term effect on neuronal tissue. Together, these results suggest that APTES coatings are ultimately detrimental to chronic neural recordings. Furthermore, interpretations of studies using APTES as a functionalization step should consider the potential consequences if the final functionalization step is incomplete
Development of an International Standard Set of Outcomes and Measurement Methods for Routine Practice for Infants, Children, and Adolescents with Epilepsy: The International Consortium for Health Outcomes Measurement Consensus Recommendations
No full textAt present, there is no internationally accepted set of core outcomes or measurement methods for epilepsy clinical practice. The International Consortium for Health Outcomes Measurement (ICHOM) convened an international working group of experts in epilepsy, people with epilepsy, and their representatives to develop minimum sets of standardized outcomes and outcome measurement methods for clinical practice. Using modified Delphi consensus methods with consecutive rounds of online voting over 12 months, a core set of outcomes and corresponding measurement tool packages to capture the outcomes were identified for infants, children, and adolescents with epilepsy. Consensus methods identified 20 core outcomes. In addition to the outcomes identified for the ICHOM Epilepsy adult standard set, behavioral, motor, and cognitive/language development outcomes were voted as essential for all infants and children with epilepsy. The proposed set of outcomes and measurement methods will facilitate the implementation of the use of patient-centered outcomes in daily practice
Investigation of Fluid Flow During Flow Boiling Inside a Horizontal Rectangular Channel with Single-Sided Heating Using Particle Image Velocimetry
No full textSubcooled flow boiling is a highly efficient cooling systems for thermal management systems. This study explores the intricate dynamics of subcooled flow boiling within a horizontal channel, investigating the impact of vapor generation on liquid-phase velocity using Particle Image Velocimetry (PIV) and advanced image processing techniques. Four mass flow rates ranging from 5–20 g/s with subcooled inlet conditions are investigated in a rectangular channel with single-sided heating. Three regions of interest along the heated channel are investigated for instantaneous PIV analysis. The PIV system captures detailed velocity profiles, illustrating the impact of varying mass flow rates and heat flux levels on flow behavior. Vapor masking techniques are introduced to enhance the precision of PIV data by mitigating interference from the vapor phase. Results demonstrate the influence of vapor bubbles on flow resistance, revealing non-uniform velocity distributions and turbulence near the liquid–vapor interface. The study emphasizes the critical role of inertia and buoyancy forces in shaping the velocity profiles. Moreover, the investigation sheds light on the effects of flow rates on the interfacial behaviors, hinting at a transition point between 10 and 15 g/s. In summary, this research contributes valuable insights into the nuanced dynamics of flow boiling, laying the foundation for future studies on turbulence, heat transfer, and phase-change phenomena in two-phase thermal management systems
On the Cogent formulation of an Elastomeric Silicone Ink material for Direct Ink Write (DIW) 3D Printing
No full textAdhesives and sealants show fine rheology with good physical and mechanical properties as viscous pastes, a possible starting point for developing direct ink writing (DIW) 3D printing ink. However, many commercial adhesives and sealants take days or weeks to cure fully. DIW 3D-printed parts made directly from these sealants are not designed for a scalable manufacturing process and high-volume production. Moreover, most of these adhesives and sealants have volume shrinkage during cure. A systematic understanding of formulation methods and design principles for an elastomeric silicone DIW ink can overcome these issues. This study presents the cogent formulation development of a 3D printable thermoset elastomer silicone that gels and cures isotropically in minutes, reducing cycle time for rapid ink development with no shrinkage during cure. More specifically, we outline the principles of raw material selection of a formulation to achieve excellent rheology, printability, synchronized working, and gel time fitting requirements closer to scalable manufacturing. The reaction kinetics and their corresponding 3D-printed structural properties are also described. Interest in future work is toward a rational DIW 3D printing ink material development protocol and use of machine learning (ML). Highlights: Formulation method flexibility and design principle of DIW ink. Raw material selection principle to achieve optimal rheology for DIW printing. Ink gel kinetics for large-scale DIW manufacturing. Hydrosilylation conversion over time at different ambient temperatures. Structural properties of DIW 3D printed parts
Three-Year Outcomes of 6-Month Paliperidone Palmitate in Adults with Schizophrenia: An Open-Label Extension Study of a Randomized Clinical Trial
No full textImportance: Long-acting injectable (LAI) antipsychotics have the potential to improve adherence and symptom control in patients with schizophrenia, promoting long-term recovery. Paliperidone palmitate (PP) once every 6 months is the first and currently only LAI antipsychotic with an extended dosing interval of 6 months. Objective: To assess long-term outcomes of PP received once every 6 months in adults with schizophrenia. Design, Setting, and Participants: In a 2-year open-label extension (OLE) study of a 1-year randomized clinical trial (RCT), eligible adults with schizophrenia could choose to continue PP every 6 months if they had not experienced relapse after receiving PP once every 3 or 6 months in the 1-year, international, multicenter, double-blind, randomized noninferiority trial. The present analysis focused on patients receiving PP every 6 months in the double-blind trial through the OLE study (November 20, 2017, to May 3, 2022). Intervention: Patients received a dorsogluteal injection of PP on day 1 and once every 6 months up to month 30. Main Outcomes and Measures: End points included assessment of relapse and change from the double-blind trial baseline to the OLE end point in Positive and Negative Syndrome Scale (PANSS) total and subscale, Clinical Global Impression-Severity (CGI-S) Scale, and Personal Social Performance (PSP) Scale scores. Treatment-emergent adverse events (TEAEs), injection site evaluations, and laboratory tests were also assessed. Results: Among 121 patients (83 [68.6%] male), mean (SD) age at baseline was 38.6 (11.24) years and mean (SD) duration of illness was 11.0 (9.45) years. At screening of the double-blind study, 101 patients (83.5%) were taking an oral antipsychotic and 20 (16.5%) were taking an LAI antipsychotic. Altogether, 5 of 121 patients (4.1%) experienced relapse during the 3-year follow-up; reasons for relapse were psychiatric hospitalization (2 [1.7%]), suicidal or homicidal ideation (2 [1.7%]), and deliberate self-injury (1 [0.8%]). Patients treated with PP every 6 months were clinically and functionally stable, and outcomes were well maintained, evidenced by stable scores on the PANSS (mean [SD] change, -2.6 [9.96] points), CGI-S (mean [SD] change, -0.2 [0.57] points), and PSP (mean [SD] change, 3.1 [9.14] points) scales over the 3-year period. In total, 101 patients (83.5%) completed the 2-year OLE. At least 1 TEAE was reported in 97 of 121 patients (80.2%) overall; no new safety or tolerability concerns were identified. Conclusions and Relevance: In a 2-year OLE study of a 1-year RCT, results supported favorable long-term outcomes of PP once every 6 months for up to 3 years in adults with schizophrenia
Preferences for Attributes of Oral Antipsychotic Treatments: Results From a Discrete-Choice Experiment in Respondents With Schizophrenia or Bipolar I Disorder
No full textBackground: Antipsychotic medications are effective treatments for schizophrenia (SZ) and bipolar I disorder (BD-I), but when presented with different treatment options, there are tradeoffs that individuals make between clinical improvement and adverse effects. As new options become available, understanding the attributes of antipsychotic medications that are valued and the tradeoffs that individuals consider when choosing among them is important. Methods: A discrete-choice experiment (DCE) was administered online to elicit preferences across 5 attributes of oral antipsychotics: treatment efficacy (i.e., improvement in symptom severity), weight gain over 6 months, sexual dysfunction, sedation, and akathisia. Eligible respondents were aged 18–64 years with a self-reported clinician diagnosis of SZ or BD-I. Results: In total, 144 respondents with SZ and 152 with BD-I completed the DCE. Of those with SZ, 50% identified themselves as female and 69.4% as White, with a mean (SD) age of 41.0 (10.1) years. Of those with BD-I, most identified themselves as female (69.7%) and as White (77.6%), with a mean (SD) age of 40.0 (10.7) years. In both cohorts, respondents preferred oral antipsychotics with better efficacy, less weight gain, no sexual dysfunction or akathisia, and lower risk of sedation. Treatment efficacy was the most important attribute, with a conditional relative importance (CRI) of 31.4% for respondents with SZ and 31.0% for those with BD-I. Weight gain (CRI = 21.3% and 23.1%, respectively) and sexual dysfunction (CRI = 23.4% and 19.2%, respectively) were adverse effects in this study that respondents most wanted to avoid. Respondents with SZ were willing to accept 9.8 lb of weight gain or \u3e 25% risk of sedation for symptom improvement; those with BD-I were willing to accept 8.5 lb of weight gain or a \u3e 25% risk of sedation. Conclusions: In this DCE, treatment efficacy was the most important attribute of oral antipsychotic medications among respondents with SZ and BD-I. Weight gain and sexual dysfunction were the adverse effects respondents most wanted to avoid; however, both cohorts were willing to accept some weight gain or sedation to obtain better efficacy. These results highlight features that patients value in antipsychotic medications and how they balance benefits and risks when choosing among treatments
Intracellular Neural Control of an Active Feeding Structure in Aplysia Using a Carbon Fiber Electrode Array
No full textBackground: To study neural control of behavior, intracellular recording and stimulation of many neurons in freely moving animals would be ideal. However, current technologies limit the number of neurons that can be monitored and manipulated. A new technology has become available for intracellular recording and stimulation which we demonstrate in the tractable nervous system of Aplysia. New method: Carbon fiber electrode arrays (whose tips are coated with platinum-iridium) were used with an in vitro feeding preparation to intracellularly record from and to control the activity of multiple neurons during feeding movements. Results: In an in vitro feeding preparation, the carbon fiber electrode arrays recorded action potentials and subthreshold synaptic potentials during feeding movements. Depolarizing or hyperpolarizing currents activated or inhibited identified neurons (respectively), manipulating the movements of the feeding apparatus. Comparison with existing method(s): Standard glass microelectrodes that are commonly used for intracellular recording are stiff, liable to break in response to movement, and require many micromanipulators to be precisely positioned. In contrast, carbon fiber arrays are less sensitive to movement, but are capable of multiple channels of intracellular recording and stimulation. Conclusions: Carbon fiber arrays are a novel technology for intracellular recording that can be used in moving preparations. They can record both action potentials and synaptic activity in multiple neurons and can be used to stimulate multiple neurons in complex patterns
Electronic Relaxation Mechanism of 9-methyl-2,6-diaminopurine and 2,6-diaminopurine-2′-deoxyribose in Solution
Get PDFProlonged ultraviolet exposure results in the formation of cyclobutane pyrimidine dimers (CPDs) in RNA. Consequently, prebiotic photolesion repair mechanisms should have played an important role in the maintenance of the structural integrity of primitive nucleic acids. 2,6-Diaminopurine is a prebiotic nucleobase that repairs CPDs with high efficiency when incorporated into polymers. We investigate the electronic deactivation pathways of 2,6-diaminopurine-2′-deoxyribose and 9-methyl-2,6-diaminopurine in acetonitrile and aqueous solution to shed light on the photophysical and excited state properties of the 2,6-diaminopurine chromophore. Evidence is presented that both are photostable compounds exhibiting similar deactivation mechanisms upon the population of the S1(ππ* La) state at 290 nm. The mechanism involves deactivation through the C2- and C6-reaction coordinates and \u3e99% of the excited state population decays through nonradiative pathways involving two conical intersections with the ground state. The radiative and nonradiative lifetimes are longer in aqueous solution compared to acetonitrile. While τ1 is similar in both derivatives, τ2 is ca. 1.5-fold longer in 2,6-diaminopurine-2′-deoxyribose due to a more efficient trapping in the S1(ππ* La) minimum. Therefore, 2,6-diaminopurine could have accumulated in significant quantities during prebiotic times to be incorporated into non-canonical RNA and play a significant role in its photoprotection
Towards a Study Protocol: A Data-Driven Workflow to Identify Error Sources in Direct Ink Write Mechatronics
Get PDFUsing Direct Ink Write (DIW) technology in a rapid and large-scale production requires reliable quality control for printed parts. Data streams generated during printing, such as print mechatronics, are massive and diverse which impedes extracting insights. In our study protocol approach, we developed a data-driven workflow to understand the behavior of sensor-measured X- and Y-axes positional errors with process parameters, such as print velocity and velocity control. We uncovered patterns showing that instantaneous changes in the velocity, when the build platform accelerates and decelerates, largely influence the positional errors, especially in the X-axis due to the hardware architecture. Since DIW systems share similar mechatronic inputs and outputs, our study protocol approach is broadly applicable and scalable across multiple systems. Graphical abstract: (Figure presented.
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