Search

3D printing has emerged as a promising fabrication technique for microfluidic devices, overcoming some of the challenges associated with conventional soft lithography. Filament-based polymer extrusion (popularly known as fused deposition modeling (FDM)) is one of the most accessible 3D printing techniques available, offering a wide range of low-cost thermoplastic polymer materials for microfluidic device fabrication. However, low optical transparency is one of the significant limitations of extrusion-based microfluidic devices, rendering them unsuitable for cell culture-related biological applications. Moreover, previously reported extrusion-based devices were largely dependent on fluorescent dyes for cell imaging because of their poor transparency. First, we aim to improve the optical transparency of FDM-based microfluidic devices to enable bright-field microscopy of cells. This is achieved using (1) transparent polymer filament materials such as poly(ethylene terephthalate) glycol (PETg), (2) optimized 3D printing process parameters, and (3) a hybrid approach by integrating 3D printed microfluidic devices with cast poly(dimethylsiloxane) (PDMS) blocks. We begin by optimizing four essential 3D printing process parameters (layer height, printing speed, cooling fan speed, and extrusion flow), affecting the overall transparency of 3D printed devices. Optimized parameters produce exceptional optical transparency close to 80% in 3D printed PETg devices. Next, we demonstrate the potential of FDM-based 3D printing to fabricate transparent micromixing devices with complex planar and nonplanar channel networks. Most importantly, cells cultured on native 3D printed PETg surfaces show excellent cell attachment, spreading, and proliferation during 3 days of culture without extracellular matrix coating or surface treatment. Next, we introduce L929 cells inside hybrid PETg-PDMS biomicrofluidic devices as a proof of concept. We demonstrate that 3D printed hybrid biomicrofluidic devices promote cell adhesion, allow bright-field microscopy, and maintain high cell viability for 3 days. Finally, we demonstrate the applicability of the proposed fabrication approach for developing 3D printed microfluidic devices from other FDM-compatible transparent polymers such as polylactic acid (PLA) and poly(methyl methacrylate) (PMMA).

Early surgical reduction of entrapped inferior rectus muscle in pediatric orbital floor fractures shows improved likelihood of complete recovery in ocular motility.

The authors describe a rare case of recurrent ectopic meningioma associated with sphenoid encephalocele in the medial anterior orbit of a 52-year-old man with a history of a resected intracranial meningioma. Typical features of ectopic meningioma are reviewed as well as potential etiologies of this very rare recurrence of intracranial meningioma in the orbit. Treatment is typically surgical excision.The authors report a rare case of recurrent orbital ectopic meningioma in the right medial canthus of a 52-year-old man.

Cystic lesions of the optic nerve are uncommon findings that have been associated with neoplasms, systemic disorders, or described as idiopathic. They have been described in a wide range of ages, with few congenital cysts having been described in infants. Surgical excision of these lesions may lead to significant morbidity as previously reported cases often involved transection of the optic nerve. The authors describe a unique case of a newborn with a rare neuroepithelial cyst of the intraorbital optic nerve that was successfully excised while sparing the optic nerve, ultimately resulting in the resolution of an afferent pupillary defect. This case demonstrates that careful surgical excision of a benign optic nerve cyst can be performed without significant morbidity to potentially preserve vision.The authors present a unique case of a congenital neuroepithelial cyst of the optic nerve that was excised while sparing the nerve, in a newborn without craniofacial dysgenesis.

Autonomic dysfunction can be associated with pupillary abnormalities. We describe a rare association of tonic pupils, congenital central hypoventilation syndrome, and Hirschsprung disease in a newborn with a mutation in the PHOX2Bgene, a key regulator of neural crest cells. Hirschsprung disease is characterized by the congenital absence of neural crest–derived intrinsic ganglion cells. Tonic pupils may result from an abnormality of the ciliary ganglion, another structure of neural crest origin. The close association of these conditions in this child suggests a common abnormality in neural crest migration and differentiation.

Traumatic penetrating injuries to the orbit from pencils, while uncommon, have a plethora of presentations, both acute and delayed. With the most incidents occurring in the pediatric population where obtaining a detailed history is difficult, the ability to effectively evaluate and diagnose these injuries is cumbersome, yet important. The authors report a patient who presented with optic neuropathy, blepharoptosis, and strabismus 10 months after an orbital injury with pencil graphite.An intraorbital graphite foreign body resulted in a delayed presentation of ophthalmoplegia, ptosis, and optic neuropathy in a pediatric patient.

Intralesional tetracycline 2% injection may offer a safe and effective treatment option for lower eyelid festoons.

This article evaluates the evidence supporting use of the tenofovir disoproxil fumarate (TDF) plus lamivudine (3​TC) combination as a dual nucleoside backbone within a triple drug antiretroviral regimen. Key trials that assess the relative efficacy, safety and resistance profile of 3​TC and emtricitabine (FTC) are discussed. Clinical use of 3​TC and FTC with two tenofovir prodrugs –TDF and tenofovir alafenamide (TAF) – is presented. Recommendations from various international guidelines for the construction of triple and emerging dual regimens are summarised. In conclusion, data suggest the therapeutic equivalence of 3​TC and FTC, especially when 3​TC is combined with TDF.

ABSTRACTBackground: Research is urgently needed to understand health care workers’ (HCWs’) experiences of moral-ethical dilemmas encountered throughout the COVID-19 pandemic, and their associations with organizational perceptions and personal well-being. This research is important to prevent long-term moral and psychological distress and to ensure that workers can optimally provide health services.Objective: Evaluate associations between workplace experiences during COVID-19, moral distress, and the psychological well-being of Canadian HCWs.Method: A total of 1362 French- and English-speaking Canadian HCWs employed during the COVID-19 pandemic were recruited to participate in an online survey. Participants completed measures reflecting moral distress, perceptions of organizational response to the pandemic, burnout, and symptoms of psychological disorders, including depression, anxiety, and posttraumatic stress disorder (PTSD).Results: Structural equation modelling showed that when organizational predictors were considered together, resource adequacy, positive work life impact, and ethical work environment negatively predicted severity of moral distress, whereas COVID-19 risk perception positively predicted severity of moral distress. Moral distress also significantly and positively predicted symptoms of depression, anxiety, PTSD, and burnout.Conclusions: Our findings highlight an urgent need for HCW organizations to implement strategies designed to prevent long-term moral and psychological distress within the workplace. Ensuring availability of adequate resources, reducing HCW risk of contracting COVID-19, providing organizational support regarding individual priorities, and upholding ethical considerations are crucial to reducing severity of moral distress in HCWs.

In Arabidopsisleaves there is a bi-phasic dose-response to applied nucleotides; i.e., lower concentrations induce stomatal opening, while higher concentrations induce closure. Two mammalian purinoceptor antagonists, PPADS and RB2, block both nucleotide-induced stomatal opening and closing. These antagonists also partially block ABA-induced stomatal closure and light-induced stomatal opening. There are two closely related Arabidopsis apyrases, AtAPY1 and AtAPY2, which are both expressed in guard cells. Here we report that low levels of apyrase chemical inhibitors can induce stomatal opening in the dark, while apyrase enzyme blocks ABA-induced stomatal closure. We also demonstrate that high concentrations of ATP induce stomatal closure in the light. Application of ATPγS and chemical apyrase inhibitors at concentrations that have no effect on stomatal closure can lower the threshold for ABA-induced closure. The closure induced by ATPγS was not observed in gpa1-3loss-of-function mutants. These results further confirm the role of extracellular ATP in regulating stomatal apertures.