Phonophobia Mediates the Relationship Between the Myelinated Vagus and Selective Mutism

When active, the myelinated vagus (the tenth cranial nerve) acts as a brake that inhibits sympathetic activity by reducing heart rate and blood pressure, and thus allows for social engagement by redirecting metabolic resources. Among those with selective mutism (SM), a disorder characterized by an inability to speak in certain situations, the vagal brake is dysregulated. One consequence of this is a weakening of the middle-ear acoustic reflex (MEAR), which helps clarify human voices and filters out low-frequency background noise, including the speaker’s own voice. I tested a proposed etiological model of SM and comorbid social anxiety disorder (SAD) by investigating the relationship between MEAR dysfunction and phonophobia (fear of one’s own voice), which were hypothesized to be positively correlated. A nonclinical sample of Bard undergraduate students was recruited. MEARs were assessed using a tympanometer and a signal-to-noise ratio hearing test; phonophobia was gauged by comparing transient anxiety levels before and after reading neutral words aloud. Analyses revealed no reliable correlation between MEAR dysfunction and phonophobia. I suggest an alternative explanation that incorporates a possible compensatory mechanism for unfiltered auditory information. These findings have implications for our understanding of the impact of the vagus nerve on the auditory system, as well as our conceptualization and treatment of SM, which is currently addressed with pharmacological interventions better suited to SAD than SM

Heat transfer and evaporation during single drop impingement onto a superheated wall

This thesis is aiming for the numerical simulation of the impingement process of a single droplet onto a wall which is superheated against the fluid's saturation temperature corresponding to the bulk pressure. The heat transfer during drop impingement is of particular importance in spray cooling which is a promising technology for the removal of high heat fluxes at a small temperature difference. While the hydrodynamics of an impinging droplet have been studied extensively in the past, the heat transfer to the droplet during the impingement process in the non-isothermal case is not yet fully understood, in particular if evaporation comes into play. Moreover, many studies on pool boiling heat transfer have demonstrated that the evaporation at the 3-phase contact line, where the solid, liquid, and gas phase meet, might contribute significantly to the overall heat transfer. Hence, it can be expected that a proper knowledge of the physical processes at the contact line might be crucial for the understanding of the entire process. However, up to now no attempt has been made to model the heat transfer of an impinging droplet just above the boiling point taking into account the microscale thermodynamic effects at the contact line. To shed light on the individual heat transfer processes involved in the overall process and to quantify their individual importance, a numerical simulation of the drop impingement is conducted within this thesis. Numerical simulations provide data on small length and time scales which cannot be resolved with available measurement techniques. The numerical model is based on the Volume of Fluid method to track the evolution of the droplet shape. Evaporation is accounted for at the surface of the droplet. Special attention is payed to the modeling of the evaporative heat transfer in the vicinity of the moving 3-phase contact line. The developed numerical model is validated with the help of highly resolved experimental data on single drop impingement. A good agreement of the model predictions to the measurements is achieved. At the same time the detailed information provided by the simulation are employed to identify the dominant phenomena governing the heat transfer during the entire impingement process. Moreover, the model is utilized to quantify the impact of the governing influence parameters. Thereby it is made use of the great advantage of numerical simulations that any parameter can be controlled individually without any additional effort. Even though the focus of this thesis is on single droplets, also the interaction of individual droplets during their impingement is addressed briefly

Clinical and surgical management of holocervical spinal cord ependymomas.

Background:Spinal ependymomas are rare tumors of the central nervous system, and those spanning the entire cervical spine are atypical. Here, we present two unusual cases of holocervical (C1-C7) spinal ependymomas. Case Description:Two patients, a 32-year-old female and a 24-year-old male presented with neck pain, motor, and sensory deficits. Sagittal MRI confirmed hypointense lesions on T1 and hyperintense regions on T2 spanning the entire cervical spine. These were accompanied by cystic cavities extending caudally into the thoracic spine and rostrally to the cervicomedullary junction. Both patients underwent gross total resection of these lesions and sustained excellent recoveries. Conclusion:Two holocervical cord intramedullary ependymomas were safely and effectively surgically resected without incurring significant perioperative morbidity

Sexual dimorphism in extracellular matrix composition and viscoelasticity of the healthy and inflamed mouse brain

Magnetic resonance elastography (MRE) has revealed sexual dimorphism in brain stiffness in healthy individuals and multiple sclerosis (MS) patients. In an animal model of MS, named experimental autoimmune encephalomyelitis (EAE), we have previously shown that inflammation-induced brain softening was associated with alterations of the extracellular matrix (ECM). However, it remained unclear whether the brain ECM presents sex-specific properties that can be visualized by MRE. Therefore, here we aimed at quantifying sexual dimorphism in brain viscoelasticity in association with ECM changes in healthy and inflamed brains. Multifrequency MRE was applied to the midbrain of healthy and EAE mice of both sexes to quantitatively map regional stiffness. To define differences in brain ECM composition, the gene expression of the key basement membrane components laminin (Lama4, Lama5), collagen (Col4a1, Col1a1), and fibronectin (Fn1) were investigated by RT-qPCR. We showed that the healthy male cortex expressed less Lama4, Lama5, and Col4a1, but more Fn1 (all p < 0.05) than the healthy female cortex, which was associated with 9% softer properties (p = 0.044) in that region. At peak EAE cortical softening was similar in both sexes compared to healthy tissue, with an 8% difference remaining between males and females (p = 0.006). Cortical Lama4, Lama5 and Col4a1 expression increased 2 to 3-fold in EAE in both sexes while Fn1 decreased only in males (all p < 0.05). No significant sex differences in stiffness were detected in other brain regions. In conclusion, sexual dimorphism in the ECM composition of cortical tissue in the mouse brain is reflected by in vivo stiffness measured with MRE and should be considered in future studies by sex-specific reference values

In Situ Monitoring of the Mechanosynthesis of the Archetypal Metal–Organic Framework HKUST-1 : Effect of Liquid Additives on the Milling Reactivity

We have applied in situ monitoring of mechanochemical reactions by high-energy synchrotron powder X-ray diffraction to study the role of liquid additives on the mechanochemical synthesis of the archetypal metal–organic framework (MOF) HKUST-1, which was one of the first and is still among the most widely investigated MOF materials to be synthesized by solvent-free procedures. It is shown here how the kinetics and mechanisms of the mechanochemical synthesis of HKUST-1 can be influenced by milling conditions and additives, yielding on occasion two new and previously undetected intermediate phases containing a mononuclear copper core, and that finally rearrange to form the HKUST-1 architecture. On the basis of in situ data, we were able to tune and direct the milling reactions toward the formation of these intermediates, which were isolated and characterized by spectroscopic and structural means and their magnetic properties compared to those of HKUST-1. The results have shown that despite the relatively large breadth of analysis available for such widely investigated materials as HKUST-1, in situ monitoring of milling reactions can help in the detection and isolation of new materials and to establish efficient reaction conditions for the mechanochemical synthesis of porous MOFs

Long-term surgical outcomes of idiopathic spinal cord herniation

AbstractBackgroundBecause of the lack of long-term postoperative follow-up studies of idiopathic spinal cord herniation (ISCH), there is little information about the long-term effectiveness and complications of the dural defect enlargement in patients with ISCH. The purpose of this study is to determine the long-term effectiveness of this procedure.MethodsSixteen patients with ISCH were treated surgically by enlargement of the dural defect. The patient's neurological status and surgical outcome were evaluated by the JOA scores for thoracic myelopathy and the recovery rate (mean follow-up period 9.6 years). Correlations between the surgical outcomes and patients' age and duration of disease were assessed retrospectively. The patients were also divided into two groups based on the location of the dural defect: the ventro-lateral (VL) group and the ventral (V) group. The difference in the duration of disease, preoperative JOA score, and the recovery rate were compared between the two groups.ResultsThere was no recurrence of ISCH after surgery. The mean recovery rate was 42.6%. There was a significant correlation between the patient's age and the recovery rate, and between the duration of disease and the recovery rate. The median recovery rate was significantly lower in the V group than in the VL group. There were no complications related to CSF leakage after surgery.ConclusionsLong-term surgical outcomes of enlargement of the dural defect for ISCH were stable and favorable without recurrences or any complications. This procedure should be considered for patients with ISCH before their neurological deficit worsens, especially for the patients in whom the dural defect is located at the ventral part of the dural canal

Delamination technique together with longitudinal incisions for treatment of Chiari I/syringomyelia complex: a prospective clinical study

<p>Abstract</p> <p>Background</p> <p>Treatment modalities in Chiari malformation type 1(CMI) accompanied by syringomyelia have not yet been standardized. Pathologies such as a small posterior fossa and thickened dura mater have been discussed previously. Various techniques have been explored to enlarge the foramen magnum and to expand the dura. The aim of this clinical study was to explore a new technique of excision of the external dura accompanied by widening the cisterna magna and making longitudinal incisions in the internal dura, without disturbing the arachnoid.</p> <p>Methods</p> <p>Ten patients with CMI and syringomyelia, operated between 2004 and 2006, formed this prospective series. All cases underwent foramen magnum decompression of 3 × 3 cm area with C1–C2 (partial) laminectomy, resection of foramen magnum fibrous band, excision of external dura, delamination and widening of internal dura with longitudinal incisions.</p> <p>Results</p> <p>Patients were aged between 25 and 58 years and occipital headache was the most common complaint. The mean duration of preoperative symptoms was 4 years and the follow-up time was 25 months. Clinical progression was halted for all patients; eight patients completely recovered and two reported no change. In one patient, there was a transient cerebrospinal fluid (CSF) fistula that was treated with tissue adhesive. While syringomyelia persisted radiologically with radiological stability in five patients; for three patients the syringomyelic cavity decreased in size, and for the remaining two it regressed completely.</p> <p>Conclusion</p> <p>Removal of the fibrous band and the outer dural layer, at level of foramen magnum, together with the incision of inner dural layer appears to be good technique in adult CMI patients. The advantages are short operation time, no need for duraplasty, sufficient posterior fossa decompression, absence of CSF fistulas as a result of extra arachnoidal surgery, and short duration of hospitalization. Hence this surgical technique has advantages compared to other techniques.</p