Geometry for low-inertia aerosol capture: Lessons from fog-basking beetles.

Water in the form of windborne fog droplets supports life in many coastal arid regions, where natural selection has driven nontrivial physical adaptation toward its separation and collection. For two species of Namib desert beetle whose body geometry makes for a poor filter, subtle modifications in shape and texture have been previously associated with improved performance by facilitating water drainage from its collecting surface. However, little is known about the relevance of these modifications to the flow physics that underlies droplets' impaction in the first place. We find, through coupled experiments and simulations, that such alterations can produce large relative gains in water collection by encouraging droplets to "slip" toward targets at the millimetric scale, and by disrupting boundary and lubrication layer effects at the microscopic scale. Our results offer a lesson in biological fog collection and design principles for controlling particle separation beyond the specific case of fog-basking beetles.

A transcription factor atlas of stem cell fate in planarians.

Whole-body regeneration requires the ability to produce the full repertoire of adult cell types. The planarian Schmidtea mediterranea contains over 125 cell types, which can be regenerated from a stem cell population called neoblasts. Neoblast fate choice can be regulated by the expression of fate-specific transcription factors (FSTFs). How fate choices are made and distributed across neoblasts versus their post-mitotic progeny remains unclear. We used single-cell RNA sequencing to systematically map fate choices made in S/G2/M neoblasts and, separately, in their post-mitotic progeny that serve as progenitors for all adult cell types. We defined transcription factor expression signatures associated with all detected fates, identifying numerous new progenitor classes and FSTFs that regulate them. Our work generates an atlas of stem cell fates with associated transcription factor signatures for most cell types in a complete adult organism.

A systematic review of enhanced resurgence paradigms.

Following successful treatment in which problem behavior is reduced, it may reemerge as a function of changes in contextual stimuli or the worsening of reinforcement conditions for an alternative response. Although understudied, preliminary research suggests that simultaneous changes in contextual stimuli and reinforcement conditions may represent particularly exigent treatment challenges that create the condition for additive or superadditive relapse. The purpose of the present review was to systematically examine the relapse literature involving simultaneous changes in contextual stimuli and reinforcement conditions in relapse tests and experimental preparations arranged to evaluate their effect on response recovery. We identified 16 empirical articles spanning 27 experiments. Although all experiments included at least one condition that experienced a change in contextual stimuli and worsening of alternative reinforcement conditions, only two experiments included the comparison conditions needed to precisely evaluate additive and superadditive relapse. Our findings establish the preclinical generality of relapse effects associated with simultaneous changes to reinforcement conditions and contextual stimuli across a range of subjects, schedule arrangements, response topographies, reinforcers, and types of contextual changes. We make several recommendations for future research based on our findings from this nascent and clinically relevant subdomain of the relapse literature.

Evaluating Predictors of Successful Postoperative Day 1 Discharge Following Posterior Fossa Tumor Resection.

BACKGROUND: Current trends in surgical neuro-oncology show that early discharges are safe and feasible with shorter lengths of stay (LOS) and fewer thromboembolic complications, fewer hospital-acquired infections, reduced costs, and greater patient satisfaction. Traditionally, infratentorial tumor resections have been associated with longer LOS and limited data exist evaluating predictors of early discharge in these patients. The objective was to assess patients undergoing posterior fossa craniotomies for tumor resection and identify variables associated with postoperative day 1 (POD1) discharge. METHODS: A retrospective review of posterior fossa craniotomies for tumor resection at our institution was performed from 2011 to 2020. Laser ablations, nontumoral pathologies, and biopsies were excluded. Demographic, clinical, surgical, and postoperative data were collected. RESULTS: One hundred and seventy-three patients were identified and 25 (14.5%) were discharged on POD1. Median length of stay (LOS) was 6 days. The POD1 discharges had significantly better preoperative Karnofsky performance scores (P < 0.001) and modified Rankin scores (P = 0.002) and more frequently presented electively (P = 0.006) and without preoperative neurologic deficits (P = 0.021). No statistically significant difference in 30-day readmissions and rates of PE, UTI, and DVT was found. Univariate logistic regression identified better preoperative functional status, elective admission, and lack of preoperative hydrocephalus as predictors of POD1 discharge, however only the latter remained significant in the multivariable model (P = 0.001). CONCLUSIONS: Discharging patients on POD1 is feasible following posterior fossa tumor resection in a select group of patients. Although we found that the only independent predictor for a longer LOS was preoperative hydrocephalus, larger, prospective studies are needed to confirm these findings.

Management of a Growth Hormone-Secreting Pituitary Macroadenoma Associated With Idiopathic Intracranial Hypertension and an Empty Sella.

Idiopathic intracranial hypertension (IIH) is a -condition associated with elevated intracranial pressure (ICP) and frequently presents with headaches, papilledema, and visual loss. Rarely, IIH has been reported in association with acromegaly. Although removal of the tumor may reverse this process, elevated ICP, especially in the setting of an otherwise empty sella, may result in a cerebrospinal fluid (CSF) leak that is exceedingly difficult to manage. We present the first case of a patient with a functional pituitary adenoma causing acromegaly associated with IIH and an otherwise empty sella and discuss our management paradigm for this rare condition.

Transradial Access Failures During Neuroangiography for Patients With Moyamoya.

BACKGROUND: Despite studies continuing to demonstrate the utility of transradial access (TRA) in neuroangiography, minimal data exist regarding predictors of TRA failure. Furthermore, although many patients with moyamoya disease/syndrome will require life-long angiographic evaluation, even less has been reported on the usage of TRA in this population. OBJECTIVE: To perform a matched analysis at our high-volume moyamoya center to determine predictors of TRA failure in these patients. METHODS: A total of 636 patients undergoing TRA for neuroangiography were identified from 2018 to 2020. Demographic and angiographic characteristics including radial artery spasm (RAS), radial anomalies, and access site conversion were compared between patients with moyamoya and the rest of the cohort. A 4:1 matched analysis, based on age and sex, was also performed to eliminate confounding variables. RESULTS: Patients with moyamoya were younger (40 vs 57 years, P < .0001), had smaller radial diameters (1.9 vs 2.6 mm, P < .0001), more commonly had a high brachial bifurcation (25.9% vs 8.5%, P = .008), more frequently experienced clinically significant RAS (40% vs 8.4%, P < .0001), and more often required access site conversion (26.7% vs 7.8%, P = .002). Increasing age was associated with less TRA failures in patients with moyamoya (odds ratio = 0.918) but more failures in the rest of the cohort (odds ratio = 1.034). In the matched analysis, patients with moyamoya continued to experience more radial anomalies, RAS, and access site conversions. CONCLUSION: Patients with moyamoya, when controlling for age and sex, have higher rates of TRA failure during neuroangiography. Increasing age in Moyamoya is inversely correlated with TRA failures suggesting that younger patients with moyamoya are at higher risk of extracranial arteriopathy.

Preprocedural Electrophysiological Monitoring in Craniofacial Surgery for a Patient with Chiari Malformation.

Head and neck positioning is a key element of craniofacial reconstructive surgery and can become challenging when intervention necessitates broad exposure of the calvarium. We present a case of craniosynostosis secondary to Apert's syndrome requiring anterior and posterior cranial vault access during surgical correction. A modified sphinx position was used that required significant neck extension. The patient had concurrent Chiari I malformation with brain stem compression so intraoperative neuromonitoring (IONM) was used to ensure that there were no negative effects on the neural elements with positioning. This highlights benefits of IONM in a setting not typically associated with its use.

Neurotensin orchestrates valence assignment in the amygdala.

The ability to associate temporally segregated information and assign positive or negative valence to environmental cues is paramount for survival. Studies have shown that different projections from the basolateral amygdala (BLA) are potentiated following reward or punishment learning1-7. However, we do not yet understand how valence-specific information is routed to the BLA neurons with the appropriate downstream projections, nor do we understand how to reconcile the sub-second timescales of synaptic plasticity8-11 with the longer timescales separating the predictive cues from their outcomes. Here we demonstrate that neurotensin (NT)-expressing neurons in the paraventricular nucleus of the thalamus (PVT) projecting to the BLA (PVT-BLA:NT) mediate valence assignment by exerting NT concentration-dependent modulation in BLA during associative learning. We found that optogenetic activation of the PVT-BLA:NT projection promotes reward learning, whereas PVT-BLA projection-specific knockout of the NT gene (Nts) augments punishment learning. Using genetically encoded calcium and NT sensors, we further revealed that both calcium dynamics within the PVT-BLA:NT projection and NT concentrations in the BLA are enhanced after reward learning and reduced after punishment learning. Finally, we showed that CRISPR-mediated knockout of the Nts gene in the PVT-BLA pathway blunts BLA neural dynamics and attenuates the preference for active behavioural strategies to reward and punishment predictive cues. In sum, we have identified NT as a neuropeptide that signals valence in the BLA, and showed that NT is a critical neuromodulator that orchestrates positive and negative valence assignment in amygdala neurons by extending valence-specific plasticity to behaviourally relevant timescales.

Countercontrol: A Relational Frame Theory (RFT) Account and Revival of a 70-Year-Old Skinnerian Term.

Countercontrol is a Skinnerian operant concept that posits that an individual's attempts to exert control over another person's behavior may evoke a countercontrolling response from the person being controlled that functions to avoid or escape the potentially aversive conditions generated by the controller. Despite Skinner's historical concerns regarding the detrimental effects of countercontrol in terms of hindering optimal societal growth and cultural evolution, the concept has not been widely applied within behavior analysis. Drawing from recent developments in rule-governed behavior and relational frame theory, this article seeks to explicate countercontrol from a contemporary behavior analytic perspective and presents several modern-day societal applications. In particular, a relational frame theory account of rule-governed behavior is used as a framework to elucidate the behavioral processes by which rule-following occurs (or fails to occur) in the context of countercontrol. Implications of a renewed focus on countercontrol for understanding pressing societal issues are also discussed.

Micromechanical Origin of Plasticity and Hysteresis in Nestlike Packings.

Disordered packings of unbonded, semiflexible fibers represent a class of materials spanning contexts and scales. From twig-based bird nests to unwoven textiles, bulk mechanics of disparate systems emerge from the bending of constituent slender elements about impermanent contacts. In experimental and computational packings of wooden sticks, we identify prominent features of their response to cyclic oedometric compression: nonlinear stiffness, transient plasticity, and eventually repeatable velocity-independent hysteresis. We trace these features to their micromechanic origins, identified in characteristic appearance, disappearance, and displacement of internal contacts.

Patient and family involvement in Choosing Wisely initiatives: a mixed methods study.

BACKGROUND: Patients are important stakeholders in reducing low-value care, yet mechanisms for optimizing their involvement in low-value care remain unclear. To explore the role of patients in the development and implementation of Choosing Wisely recommendations to reduce low-value care and to assess the likelihood that existing patient resources will change patient health behaviour. METHODS: Three phased mixed-methods study: 1) content analysis of all publicly available Choosing Wisely clinician lists and patient resources from the United States of America and Canada. Quantitative data was summarized with frequencies and free text comments were analyzed with qualitative thematic content analysis; 2) semi-structured telephone interviews with a purposive sample of representatives of professional societies who created Choosing Wisely clinician lists and members of the public (including patients and family members). Interviews were transcribed verbatim, and two researchers conducted qualitative template analysis; 3) evaluation of Choosing Wisely patient resources. Two public partners were identified through the Calgary Critical Care Research Network and independently answered two free text questions "would this change your health behaviour" and "would you discuss this material with a healthcare provider". Free text data was analyzed by two researchers using thematic content analysis. RESULTS: From the content analysis of 136 Choosing Wisely clinician lists, six reported patient involvement in their development. From 148 patient resource documents that were mapped onto a conceptual framework (Inform, Activate, Collaborate) 64% described patient engagement at the level of Inform (educating patients). From 19 interviews stakeholder perceptions of patient involvement in reducing low-value care were captured by four themes: 1) impact of perceived power dynamics on the discussion of low-value care in the clinical interaction, 2) how to communicate about low-value care, 3) perceived barriers to patient involvement in reducing low-value care, and 4) suggested strategies to engage patients and families in Choosing Wisely initiatives. In the final phase of work in response to the question "would this change your health behaviour" two patient partners agreed 'yes' on 27% of patient resources. CONCLUSIONS: Opportunities exist to increase patient and family participation in initiatives to reduce low-value care.

Radial Access Techniques.

Transradial access (TRA) has gained traction in neurointerventions as studies continue to demonstrate improved access site safety and equivalent end artery effectiveness when compared with traditional transfemoral techniques. Herein, we describe the technical nuances of obtaining TRA with a focus on distal TRA, left TRA, and sheathless TRA using larger bore catheters. We also discuss various strategies to avoid access site conversion if radial artery spasm or radial anomalies are encountered and offer some solutions for forming the Simmons catheter especially when it cannot be performed in the descending aorta. Lastly, we provide some insights regarding contraindications to TRA.

Iatrogenic radial arteriovenous fistula closure via intraluminal compression in a patient with fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is an arteriopathy of medium-sized vessels causing pathological arterial wall fragility. However, only minimal data exist on evaluating the risk of transradial access (TRA) in these patients. We describe the case of a woman in her 70s who underwent left middle meningeal artery embolisation for an acute-on-chronic subdural haematoma via right TRA. Radial angiography demonstrated significant FMD throughout the entire right upper extremity. To prevent radial spasm, a 23 cm sheath was placed without difficulty. However, follow-up angiography demonstrated the presence of a new radial arteriovenous fistula (AVF) just distal to the brachial bifurcation. Since no forearm haematoma or limb ischaemia developed, the procedure was continued transradially. After embolisation, the guide catheter was removed and follow-up angiography demonstrated resolution of the fistula. This case illustrates that, in the absence of concerning clinical signs, compression from the guide catheter alone may facilitate thrombosis of an acutely identified iatrogenic radial AVF.

Republished: Manual reduction of a radial artery loop under direct fluoroscopic visualization.

Transradial access has become increasingly used in neurointerventions because it reduces access site complications. However, radial artery anomalies can be difficult to navigate, often necessitating conversion to femoral access. We describe the case of a female patient in her early 70 s who underwent preoperative embolization of a carotid body tumor via right transradial access. Her radial angiogram demonstrated the presence of a radial artery loop which was successfully navigated with a triaxial system but would not spontaneously reduce even after the guide catheter was advanced into the subclavian artery. However, manual manipulation of the catheters in the antecubital fossa under direct fluoroscopic visualization reduced the loop allowing the procedure to continue transradially. Although a majority of radial loops can be traversed and reduced using standard techniques, this case demonstrates that manual reduction can be successful when other measures fail. We recommend attempting this method before converting the access site.

Rupture of a de novo dural AV fistula following adult cerebral AVM resection.

Acquired unruptured dural arteriovenous fistulas (DAVFs) have been described; however, ruptured de novo DAVFs remain exceedingly rare. We describe the case of a man in his 40s who presented with a recurrent intraparenchymal haemorrhage several years after angiographic cure of an intracranial arteriovenous malformation (AVM). Repeat angiography identified a new Cognard type IV DAVF anterior to the prior craniotomy. He underwent preoperative embolisation followed by craniotomy to completely obliterate the fistulous point. This case illustrates the need for close monitoring of AVM patients, even after complete obliteration, as local recrudescence of arteriovenous shunting can occur even in adulthood.

Staged embolisation of a giant torcular dural sinus malformation in a neonate.

Torcular dural sinus malformations (tDSMs) represent a rare subset of paediatric cerebrovascular malformations and are often diagnosed antenatally via ultrasound. The management of these in utero lesions remains controversial as previous studies suggested elective termination of the pregnancy because of their presumably high mortality and severe long-term morbidity. However, more recent evaluations have suggested that the overall prognosis for infants harbouring these lesions may be much better than previously believed. As such, we present the case of a neonate with a giant tDSM, diagnosed in utero, who was treated postnatally via staged transarterial and transvenous embolisation to alleviate worsening obstructive hydrocephalus and brainstem compression. We provide details regarding the surgical approach and long-term neurological outcomes for this patient. To the best of our knowledge, this is one of the largest reported tDSM presented in the literature.

Attractive forces slow contact formation between deformable bodies underwater.

Thermodynamics tells us to expect underwater contact between two hydrophobic surfaces to result in stronger adhesion compared to two hydrophilic surfaces. However, the presence of water changes not only energetics but also the dynamic process of reaching a final state, which couples solid deformation and liquid evacuation. These dynamics can create challenges for achieving strong underwater adhesion/friction, which affects diverse fields including soft robotics, biolocomotion, and tire traction. Closer investigation, requiring sufficiently precise resolution of film evacuation while simultaneously controlling surface wettability, has been lacking. We perform high-resolution in situ frustrated total internal reflection imaging to track underwater contact evolution between soft-elastic hemispheres of varying stiffness and smooth-hard surfaces of varying wettability. Surprisingly, we find the exponential rate of water evacuation from hydrophobic-hydrophobic (adhesive) contact is three orders of magnitude lower than that from hydrophobic-hydrophilic (nonadhesive) contact. The trend of decreasing rate with decreasing wettability of glass sharply changes about a point where thermodynamic adhesion crosses zero, suggesting a transition in mode of evacuation, which is illuminated by three-dimensional spatiotemporal height maps. Adhesive contact is characterized by the early localization of sealed puddles, whereas nonadhesive contact remains smooth, with film-wise evacuation from one central puddle. Measurements with a human thumb and alternatively hydrophobic/hydrophilic glass surface demonstrate practical consequences of the same dynamics: adhesive interactions cause instability in valleys and lead to a state of more trapped water and less intimate solid-solid contact. These findings offer interpretation of patterned texture seen in underwater biolocomotive adaptations as well as insight toward technological implementation.

Supralesional Ablation Volumes Are Feasible in the Posterior Fossa and May Provide Enhanced Symptomatic Relief.

BACKGROUND: Laser interstitial thermal therapy (LITT) for posterior fossa lesions remains rare as the small size of the infratentorial compartment, proximity to the brainstem, and thickness/angulation of the occipital bone creates barriers to procedural success. Furthermore, evaluation of the effect of ablation volume on outcomes is limited. OBJECTIVE: To analyze our institutional experience with LITT in the posterior fossa stratifying perioperative and long-term outcomes by ablation volumes. METHODS: Seventeen patients with posterior fossa lesions treated with LITT from 2013 to 2020 were identified. Local progression-free survival (PFS), overall survival, steroid dependence, and edema reduction were evaluated with Kaplan-Meier analysis grouped by ablation volume. Preoperative, postoperative, and last known Karnofsky Performance Status (KPS) were compared using a matched paired t test. RESULTS: No differences in pathology, preoperative KPS, or preoperative lesion volume were found between patients with total (100%-200% increase in pre-LITT lesion volume) versus radical (>200% increase in pre-LITT lesion volume) ablations. Patients who underwent radical ablation had a higher postoperative KPS (93 vs 82, P = .02) and higher KPS (94 vs 87, P = .04) and greater reduction in perilesional edema at last follow-up (P = .01). Median follow-up was 80.8 wk. CONCLUSION: Despite obvious anatomical challenges, our results demonstrate that radical ablations are both feasible and safe in the posterior fossa. Furthermore, radical ablations may lead to greater decreases in perilesional edema and improved functional status both immediately after surgery and at last follow-up. Thus, LITT should be considered for patients with otherwise unresectable or radioresistant posterior fossa lesions.

Manual reduction of a radial artery loop under direct fluoroscopic visualization.

Transradial access (TRA) has become increasingly utilized in neurointerventions because it reduces access site complications. However, radial artery anomalies can be difficult to navigate, often necessitating conversion to femoral access. We describe the case of a female patient in her early 70s who underwent preoperative embolization of a carotid body tumor via right TRA. Her radial angiogram demonstrated the presence of a radial artery loop which was successfully navigated with a triaxial system but would not spontaneously reduce, even after the guide catheter was advanced into the subclavian artery. However, manual manipulation of the catheters in the antecubital fossa under direct fluoroscopic visualization reduced the loop, allowing the procedure to continue transradially. Although most radial loops can be traversed and reduced using standard techniques, this case demonstrates that manual reduction can be successful when other measures fail. We recommend attempting this method prior to converting the access site.

Transient ipsilateral mydriasis following carotid artery stenting.

BACKGROUND AND IMPORTANCE: One of the most feared and devastating complications of carotid revascularization procedures is hyperperfusion hemorrhage. The acute onset of an ipsilateral mydriatic pupil following carotid endarterectomy (CEA) or carotid artery stenting (CAS) should prompt immediate neurosurgical evaluation to rule out hyperperfusion injury. CLINICAL PRESENTATION: We describe a case of benign, transient ipsilateral mydriasis following CAS. After undergoing right common and internal carotid artery (ICA) angioplasty and stenting with distal embolic protection, the patient developed anisocoria with a right-sided 5 mm minimally reactive pupil. Imaging demonstrated no acute pathology, and the mydriasis resolved spontaneously within 48 hours. We hypothesise that the pathophysiologic mechanism is secondary to transient ischemia of parasympathetic structures within the petrous/cavernous ICA from arterial ostium occlusion that occurred during device placement. Alternatively, sympathetic stimulation during angioplasty is also plausible. CONCLUSIONS: Although an ipsilateral mydriatic pupil following carotid revascularization necessitates evaluation, it may represent a self-limiting process especially in the absence of other focal neurologic deficits.