Minimal logical teleology in artifacts and biology connects the two domains and frames mechanisms via epistemic circularity.

The understanding of artifacts and biological phenomena has often influenced each other. This work argues that at the core of these epistemic bridges there are shared teleological notions and explanations manifested in analogies between artifacts and biological phenomena. To this end, I first propose a focus on the logical structure of minimal teleological explanations, which renders said epistemic bridges more evident than an ontological or metaphysical approach to teleology, and which can be used to describe scientific practices in different areas by virtue of formal generality and minimalism (section 2). Second, I show how this approach highlights some epistemic features shared by the understanding of artifacts and biological phenomena, like a specific kind of epistemic circularity, and how functional analogies between artifacts and biological phenomena translate such epistemic circularity from one domain to the other (section 3). Third, I conduct a case study on the scientific practice around the brain's "compass", showing how the understanding of artifacts influences purpose ascription and measurement, and frames mechanisms in biology, especially in areas where purpose ascription is most difficult, like cognitive neuroscience (sections 4 and 5).

A phenomenological computational model of the evoked action potential fitted to human cochlear implant responses.

There is a growing interest in biomedical engineering in developing procedures that provide accurate simulations of the neural response to electrical stimulus produced by implants. Moreover, recent research focuses on models that take into account individual patient characteristics. We present a phenomenological computational model that is customized with the patient's data provided by the electrically evoked compound action potential (ECAP) for simulating the neural response to electrical stimulus produced by the electrodes of cochlear implants (CIs). The model links the input currents of the electrodes to the simulated ECAP. Potentials and currents are calculated by solving the quasi-static approximation of the Maxwell equations with the finite element method (FEM). In ECAPs recording, an active electrode generates a current that elicits action potentials in the surrounding auditory nerve fibers (ANFs). The sum of these action potentials is registered by other nearby electrode. Our computational model emulates this phenomenon introducing a set of line current sources replacing the ANFs by a set of virtual neurons (VNs). To fit the ECAP amplitudes we assign a suitable weight to each VN related with the probability of an ANF to be excited. This probability is expressed by a cumulative beta distribution parameterized by two shape parameters that are calculated by means of a differential evolution algorithm (DE). Being the weights function of the current density, any change in the design of the CI affecting the current density produces changes in the weights and, therefore, in the simulated ECAP, which confers to our model a predictive capacity. The results of the validation with ECAP data from two patients are presented, achieving a satisfactory fit of the experimental data with those provided by the proposed computational model.

Extra-corporeal membrane oxygenation and emergency C-section for a pregnant COVID-19 positive patient.

INTRODUCTION: Data on extra-corporeal membrane oxygenation (ECMO) therapy for pregnant patients with Coronavirus 2019 (COVID-19) infection are limited. Here we report a case of an emergency cesarean section performed while the COVID-19 positive mother was on ECMO support. CASE REPORT: A 36-year-old COVID-19 positive patient at 26 weeks gestational age presented with respiratory failure requiring extra-corporeal membrane oxygenation therapy. Nine days later fetal distress demanded an emergency C-section. After 5 weeks on ECMO, the patient was weaned off. Both mother and child were discharged. DISCUSSION: The decision to perform an urgent C-section is one that requires meticulous thought from the attending team. Pulmonary maturation is key as pregnancy may need to be terminated at any time during ECMO. CONCLUSION: Data on ECMO support for pregnant patients with COVID-19 infection are scarce. Best results can be achieved ensuring adequate anticoagulation, meticulous choice of cannulas, continued fetal monitoring, early lung maturation, and precision timing of delivery.

MitraClip as bridge to mitral valve replacement in the setting of ischemic cardiogenic shock and papillary muscle rupture.

MitraClip implantation has been reported in severe mitral regurgitation following ischemic papillary muscle rupture in surgically high-risk patients with cardiogenic shock. Here we present a case of a 68-year-old female patient who suffered an ischemic papillary muscle rupture resulting in severe mitral prolapse and had a MitraClip implanted. Three months later, due to progressive symptoms, she was taken to surgery and had an elective minimally invasive mitral valve replacement. Informed consent was given and ethics board approval was obtained.

Long-Term Follow-Up on Bilateral Posterior Hypothalamic Deep Brain Stimulation for Treating Refractory Aggressive Behavior in a Patient with Cri du Chat Syndrome: Analysis of Clinical Data, Intraoperative Microdialysis, and Imaging Connectomics.

Posterior hypothalamic-deep brain stimulation (pHyp-DBS) has been reported as a successful treatment for reducing refractory aggressive behaviors in patients with distinct primary diagnoses. Here, we report on a patient with cri du chat syndrome presenting severe self-injury and aggressive behaviors toward others, who was treated with pHyp-DBS. Positive results were observed at long-term follow-up in aggressive behavior and quality of life. Intraoperative microdialysis and imaging connectomics analysis were performed to investigate possible mechanisms of action. Our results suggest the involvement of limbic and motor areas and alterations in main neurotransmitter levels in the targeted area that are associated with positive results following treatment.

Bench bioprosthetic aortic valve replacement in a donor heart before transplantation.

Critical donor shortages have impulsed the need to expand donor heart eligibility through the use of marginal hearts in cardiac transplantation. Donor valvular disease has been considered as an absolute contraindication for transplant. A 39-year-old male patient with end-stage non-compaction cardiomyopathy, an INTERMACS II heart failure, and a left ventricular ejection fraction of 8% was taken to an orthotopic heart transplantation. During donor bench graft examination, a congenital bicuspid and calcified aortic valve was found. The native bicuspid valve was removed and the annular calcification debrided; a #21 bioprosthetic aortic valve was then implanted.

MitraClip as bridge to mitral valve replacement in the setting of ischemic cardiogenic shock and papillary muscle rupture.

MitraClip implantation has been reported in severe mitral regurgitation following ischemic papillary muscle rupture in surgically high-risk patients with cardiogenic shock. Here we present a case of a 68-year-old female patient who suffered an ischemic papillary muscle rupture resulting in severe mitral prolapse and had a MitraClip implanted. Three months later, due to progressive symptoms, she was taken to surgery and had an elective minimally invasive mitral valve replacement. Informed consent was given and ethics board approval was obtained.

Peri-operative nutrition in cardiovascular surgery: current pitfalls and future directions.

In the field of cardiovascular surgery, many areas are frequently evaluated to improve patient outcomes. Even though cardiac surgery has advanced significantly, peri-operative nutrition remains an area needing special attention and is under-considered in patient results. The three portions of cardiac surgical nutrition optimization are pre-operative, intra-operative and post-operative. All these, merit important clinical intervention which when done properly can significantly improve patient recovery and reduce morbidity and mortality. Here we provide a narrative review and recommendations for peri-operative nutritional optimization in cardiac surgery.

Primary Maxillary Reconstruction With Fibula Flap and Dental Implants: A Comparative Study Between Virtual Surgical Planning and Standard Surgery in Class IIC Defects.

PURPOSE: Oncological patients who undergo bilateral subtotal maxillectomies develop functional and esthetic sequelae that require immediate reconstruction. The purpose of this study is to evaluate the primary reconstruction of maxillary defects with fibula flap and dental implants assisted by virtual surgical planning (VSP) and to assess the postoperative outcomes compared with standard surgery. MATERIAL AND METHODS: A retrospective study was designed between January 2016 and April 2020 with 12 oncologic patients who underwent subtotal bilateral maxillectomy. Six consecutive patients were treated by standard surgical procedure (SS) at the beginning of the study. In 2018, the VSP was implemented, and 6 consecutive patients were treated using this technique. All patients were rehabilitated with Ticare implants and implant prostheses. Anatomic position of the bone, bone apposition, change of vertical distance, and horizontal shift, the operative and ischemia time, the esthetic results, and the functional rehabilitation were evaluated and compared. RESULTS: The position of the bone in anatomical position was 100% in the VSP group vs 66% in the SS group. The bone apposition was 100% in the VSP group vs 83.3%. The change of vertical distance and the horizontal shift were lower in the VSP group (P < .05). The ischemia time and operative time were shorter in the VSP group (P < .05). A good esthetic result was achieved in 83.3% in the VSP group vs 33.3% in the SS group; 81 dental implants and 1 zygomatic implant were placed. The success rate was 95% in the VSP group and 92.6% in the SS group. All patients were rehabilitated with implant prosthesis. CONCLUSIONS: VSP improves the accuracy of midface reconstruction (class IIC defect) with a better anatomical position of the bone, a higher rate of bone contact, and a lower change in vertical distance compared with standard surgery. It significantly improves the esthetic result, reduces ischemia time, and operation time.

Secondary Cervicofacial Soft Tissue Reconstruction With Upper Trapezius Myocutaneous Flap in "Frozen Neck" With Bone Flap and Reconstructive Plate Exposure.

ABSTRACT: A frozen neck is a scarred neck with severe fibrosis with a loss of tissue planes secondary to prior irradiation with or without surgery. The purpose of this study was to evaluate the outcomes of cervicofacial reconstruction in patients with soft tissue defects and bone flap and reconstruction plate exposure with the upper trapezius myocutaneous flap. Fifteen oncologic patients with prior surgery and radiotherapy developed soft tissue dehiscence with bone and osteosynthesis material exposure. All patients had either a frozen neck or a vessel-depleted neck. The soft tissue defects were reconstructed, the osteosynthesis material was removed and the bone flap exposure was covered in all patients. One patient developed a seroma and 1 patient reported wound dehiscence. In terms of esthetic results, 6 patients referred a good esthetic result, whereas 8 patients referred a fair result and 1 patient a poor result. Two patients with prior radical neck dissection reported a poor functional result in the ipsilateral shoulder, previously to secondary reconstruction. Functional neck dissection was performed in 10 patients, 8 patients referred a good functional outcome and 2 patients reported a fair result. The upper trapezius flap is an extremely reliable source for secondary cervicofacial soft tissue reconstruction in "frozen neck." In comparison with other locoregional flaps, the upper trapezius flap fulfills all aesthetic and functional criteria for secondary cervicofacial soft tissue reconstruction.

Marangoni puffs: dramatically enhanced dissolution of droplets with an entrapped bubble.

We present a curious effect observed during the dissolution process of water-immersed long-chain alcohol drops with an entrapped air bubble. These droplets dissolve while entrapping an air bubble pinned at the substrate. We qualitatively describe and explain four different phases that are found during the dissolution of this kind of system. The dissolution rate in the four phases differ dramatically. When the drop-water interface and the air bubble contact each other, rapid cyclic changes of the morphology are found: The breakage of the thin alcohol layer in between the bubble and the water leads to the formation of a three phase contact line. If the surface tension of the water-air interface supersedes those of the alcohol-water and alcohol-air interfaces, alcohol from the droplet is pulled upwards, leading to a closure of the air-water interface and the formation of a new thin alcohol film, which then dissolves again, leading to a repetition of the series of events. We call this sequence of events Marangoni puffing. This only happen for alcohols of appropriate surface tension. The Marangoni puffing is an intermediate state. In the final dissolution phases the Marangoni forces dramatically accelerate the dissolution rate, which then becomes one order of magnitude faster than the purely buoyancy-convective driven dissolution. Our results have bearing on various dissolution processes in multicomponent droplet systems.

EFFICACY AND SAFETY OF A TREAT-AND-EXTEND REGIMEN WITH AFLIBERCEPT IN TREATMENT-NAIVE PATIENTS WITH TYPE 3 NEOVASCULARIZATION: A 52-Week, Single-Arm, Multicenter Trial.

PURPOSE: To evaluate 52-week efficacy and safety of a treat-and-extend regimen of intravitreal aflibercept 2 mg on treatment-naive Type 3 neovascularization lesions. METHODS: Phase IV, prospective, open-label, single-arm, multicenter trial including patients with untreated Stage I/II Type 3 neovascularization lesions and baseline best-corrected visual acuity between 78 and 23 Early Treatment Diabetic Retinopathy Study letters. Primary endpoint: mean change in best-corrected visual acuity from baseline at 52 weeks. RESULTS: Thirty-two eyes from 32 patients were included (mean ± SD age: 78.2 ± 7.7 years, 68.8% females, baseline best-corrected visual acuity: 57.9 ± 15.4 [Snellen fraction 20/70]). Best-corrected visual acuity increased by 10.5 ± 15.9 Early Treatment Diabetic Retinopathy Study letters at Week 52 (P = 0.0001). The mean foveal and choroidal thickness decreased by 129.1 ± 80.1 µm (P < 0.0001) and 64.3 ± 96.5 (P = 0.0001), respectively. The proportion of patients with intraretinal/subretinal fluid decreased from 28 (87.5%) at baseline to 3 (11.5%) at Week 52 (P < 0.0001). Pigment epithelial detachment and lesion area showed nonsignificant changes over 52 weeks. The mean number of injections was 8.0 ± 2.0. Seven (21.9%) patients experienced treatment-related adverse events and two (6.3%) experienced serious adverse events; one (3.1%) ocular serious adverse event requiring treatment withdrawal, endophthalmitis, and one (3.1%) nonocular spontaneously resolved serious adverse event, palpitations. One (3.1%) patient experienced an APTC ATE: nonfatal stroke not related to trial treatment. CONCLUSION: A treat-and-extend regimen of aflibercept improves visual acuity and retinal edema in eyes with Type 3 neovascularization over 52 weeks with good tolerability.

Equilibrium Drop Shapes on a Tilted Substrate with a Chemical Step.

We calculate the equilibrium shape of a droplet sitting on a tilted substrate with a "chemical step", that is, different lypophilicity at the two sides of the step. This problem can be generalized to that of a droplet experiencing a body force, pushing it from the lyophilic part to the lyophobic part of the substrate. We present phase diagrams, in which we show for which droplet sizes there are dynamically inaccessible equilibrium shapes. We also identify what determines the threshold volume. While this given system was studied previously in the literature using contact angle hysteresis laws, we present the full static thermodynamical solution of the interfacial energy including the contact energy, while omitting the hysteresis effects from the contact line.

Morphology of Evaporating Sessile Microdroplets on Lyophilic Elliptical Patches.

The evaporation of droplets occurs in a large variety of natural and technological processes such as medical diagnostics, agriculture, food industry, printing, and catalytic reactions. We study the different droplet morphologies adopted by an evaporating droplet on a surface with an elliptical patch with a different contact angle. We perform experiments to observe these morphologies and use numerical calculations to predict the effects of the patched surfaces. We observe that tuning the geometry of the patches offers control over the shape of the droplet. In the experiments, the drops of various volumes are placed on elliptical chemical patches of different aspect ratios and imaged in 3D using laser scanning confocal microscopy, extracting the droplet's shape. In the corresponding numerical simulations, we minimize the interfacial free energy of the droplet, by employing Surface Evolver. The numerical results are in good qualitative agreement with our experimental data and can be used for the design of micropatterned structures, potentially suggesting or excluding certain morphologies for particular applications. However, the experimental results show the effects of pinning and contact angle hysteresis, which are obviously absent in the numerical energy minimization. The work culminates with a morphology diagram in the aspect ratio vs relative volume parameter space, comparing the predictions with the measurements.

The Posterior Lumbar Epidural Space: Three-Dimensional Reconstruction of High-Resolution MRI: Real and Potential Epidural Spaces and Their Content In Vivo.

OBJECTIVE: Our aim was to study the posterior lumbar epidural space with 3D reconstructions of magnetic resonance images (MRIs) and to compare and validate the findings with targeted anatomic microdissections. DESIGN: We performed 3D reconstructions of high-resolution MRIs from seven patients and normal-resolution MRIs commonly used in clinical practice from 196 other random patients. We then dissected and photographed the lumbar spine areas of four fresh cadavers. RESULTS: From the 3D reconstructions of the MRIs, we verified that the distribution of the posterior fat pad had an irregular shape that resembled a truncated pyramid. It spanned between the superior margin of the lamina of the caudad vertebra and beyond the inferior margin to almost halfway underneath the cephalad lamina of the cranial vertebra, and it was not longitudinally or circumferentially continuous. The 3D reconstructions of the high-definition MRI also consistently revealed a prelaminar fibrous body that was not seen in most of the usually used low-definition MRI reconstructions. Targeted microdissections confirmed the 3D reconstruction findings and also showed the prelaminar tissue body to be fibrous, crossing from side to side anterior to the cephalad half of each lamina, and spanning from the dural sac to the laminae. CONCLUSIONS: Three-dimensional reconstructions and targeted microdissection revealed the unique appearance of posterior fat pads and a prelaminar fibrous body. The exact consistency, presence, prevalence with age, presence in other regions, and function of this body are unknown and require further research.

Novel Bioactive and Antibacterial Acrylic Bone Cement Nanocomposites Modified with Graphene Oxide and Chitosan.

Acrylic bone cements (ABCs) have played a key role in orthopedic surgery mainly in arthroplasties, but their use is increasingly extending to other applications, such as remodeling of cancerous bones, cranioplasties, and vertebroplasties. However, these materials present some limitations related to their inert behavior and the risk of infection after implantation, which leads to a lack of attachment and makes necessary new surgical interventions. In this research, the physicochemical, thermal, mechanical, and biological properties of ABCs modified with chitosan (CS) and graphene oxide (GO) were studied. Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) scanning electron microscopy (SEM), Raman mapping, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), compression resistance, mechanical dynamic analysis (DMA), hydrolytic degradation, cell viability, alkaline phosphatase (ALP) activity with human osteoblasts (HOb), and antibacterial activity against Gram-negative bacteria Escherichia coli were used to characterize the ABCs. The results revealed good dispersion of GO nanosheets in the ABCs. GO provided an increase in antibacterial activity, roughness, and flexural behavior, while CS generated porosity, increased the rate of degradation, and decreased compression properties. All ABCs were not cytotoxic and support good cell viability of HOb. The novel formulation of ABCs containing GO and CS simultaneously, increased the thermal stability, flexural modulus, antibacterial behavior, and osteogenic activity, which gives it a high potential for its uses in orthopedic applications.

Zipping-Depinning: Dissolution of Droplets on Micropatterned Concentric Rings.

The control of the surface wettability is of great interest for technological applications as well as for the fundamental understanding of surface phenomena. In this article, we describe the dissolution behavior of droplets wetting a micropatterned surface consisting of smooth concentric circular grooves. In the experiments, a droplet of alcohol (1-pentanol) is placed onto water-immersed micropatterns. When the drops dissolve, the dynamics of the receding contact line occurs in two different modes. In addition to the stick-jump mode with jumps from one ring to the next inner one, our study reveals a second dissolution mode, which we refer to as zipping-depinning. The velocity of the zipping-depinning fronts is governed by the dissolution rate. At the early stage of the droplet dissolution, our experimental results are in good agreement with the theoretical predictions by Debuisson et al. [ Appl. Phys. Lett. 2011 , 99 , 184101 ]. With an extended model, we can accurately describe the dissolution dynamics in both stick-jump and zipping-depinning modes.

Effect of 2,6-Bis-(1-hydroxy-1,1-diphenyl-methyl) Pyridine as Organic Additive in Sulfide NiMoP/γ-Al2O3 Catalyst for Hydrodesulfurization of Straight-Run Gas Oil.

The effect of 2,6-bis-(1-hydroxy-1,1-diphenyl-methyl) pyridine (BDPHP) in the preparation of NiMoP/γ-Al2O3 catalysts have been investigated in the hydrodesulfurization (HDS) of straight-run gas oil. The γ-Al2O3 support was modified by surface impregnation of a solution of BDPHP to afford BDPHP/Ni molar ratios (0.5 and 1.0) in the final composition. The highest activity for NiMoP materials was found when the molar ratio of BDPHP/Ni was of 0.5. X-ray diffraction (XRD) results revealed that NiMoP (0.5) showed better dispersion of MoO3 than the NiMoP (1.0). Fourier transform infrared spectroscopy (FT-IR) results indicated that the organic additive interacts with the γ-Al2O3 surface and therefore discards the presence of Mo or Ni complexes. Raman spectroscopy suggested a high Raman ratio for the NiMoP (0.5) sample. The increment of the Mo=O species is related to a major availability of Mo species in the formation of MoS2. The temperature programmed reduction (TPR) results showed that the NiMoP (0.5) displayed moderate metal-support interaction. Likewise, X-ray photoelectron spectroscopy (XPS) exhibited higher sulfurization degree for NiMoP (0.5) compared with NiMoP (1.0). The increment of the MoO3 dispersion, the moderate metal-support interaction, the increase of sulfurization degree and the increment of Mo=O species provoked by the BDPHP incorporation resulted in a higher gas oil HDS activity.