Correlations Between Intracranial Aneurysms And Thoracic Aortic Aneurysms

This project investigates the clinical occurrence of concurrent thoracic aortic aneurysms (TAA) and intracranial aneurysms (ICA). We hypothesized that patients with a TAA have an increased risk of harboring a concurrent ICA, and likewise that patients with an ICA have an increased risk of harboring a concurrent TAA relative to the general population. In a separate arm of this project, we hypothesized that a pre-defined gene expression profile, based on the expression levels of 41 specific genes measured in peripheral blood cells, will exhibit a characteristic expression pattern in ICA patients and thereby have utility in detecting the presence of ICA. To accomplish the first objective of this project, we reviewed the charts of patients with TAA who also had recent intracranial imaging to document the prevalence of concurrent ICA and compared this rate to the ICA prevalence in the general population. Likewise, we reviewed the charts of patients with ICA who also had recent thoracic imaging to document the prevalence of concurrent TAA. To investigate the gene expression profile for detecting ICA, we collected peripheral blood samples from ICA patients and non- aneurysmal controls and measured the expression levels of 39 pre-defined genes in a signature aneurysm profile using real-time PCR. The observed pattern of expression of these genes was compared to a pre-defined signature aneurysm pattern to predict the aneurysm status of each sample. We found that 9.0% of 212 TAA patients we studied harbor a concurrent ICA. Patients with descending TAA and hypertension had significantly higher rates of concurrent ICA. We also found that 4.5% of 359 ICA patients we studied harbor a concurrent TAA. ICA patients over 70 years of age had an increased rate of concurrent TAA. We also analyzed gene expression in the blood samples of 17 ICA patients and 15 controls. By comparing the observed pattern of gene expression to a predefined signature aneurysm pattern, we were able to detect ICA from a peripheral blood test with an 88% sensitivity and overall accuracy of 63%. In conclusion, this project finds that patients with TAA are at an increased risk relative to the general population of harboring a concurrent ICA. Likewise, patients with ICA are at an increased risk relative to the general population of harboring a concurrent TAA. Our early results show that a peripheral blood test based on the gene expression pattern of 39 genes holds promise as a sensitive screening test for ICA

Physical Rehabilitation of Adolescents with Postural Disorders in the Sagittal Plane and its Relation to Neurophysiology

The adolescents aged between 15 and 17 with postural disorders in the sagittal plane, who live in mountainous regions in the Carpathians, achieve less than their peers with similar postural disorders, who live in plain regions. The research aims to develop the comprehensive programme for correcting postural disorders in the sagittal plane among pupils, who live in mountainous regions in the Carpathians, using physical rehabilitation, and establish the links between empirical data of the experiment and neurosciences to develop methods of complex psychophysical and neurophysiological diagnostic and rehabilitation of adolescents with such disorders in further research. The research is based on a detailed observation of 319 adolescents aged between 15 and 17 from mountainous regions of the Ukrainian Carpathians and 94 pupils from plain regions with postural disorders in the sagittal plane. The research methods are the following: an analysis of the scientific and specialized literature; surveys and questionnaires; pedagogical tests; methods for determining the indicators of physical development, functional readiness and functions of the spine; methods of mathematical statistics, namely, the Ruffier-Dickson test, Otto test, Schober test, Thomayer test, Fleischmann test, Sedin test and spinal index, inclinometer measurements. The pupils who suffer from the stoop and round spine have shown a decrease in average values in the angles of lordosis and kyphosis curves; pupils who suffer from flat back – an increase in the angles of the sacral bone, lordosis and kyphosis curves; pupils who suffer from the round and concave back – a decrease in the angles of the sacral bone, lordosis and kyphosis curves. The implementation of the author’s programme for physical rehabilitation has made it possible to achieve a statistically significant improvement in most of the analyzed indicators. Finally, the article extrapolates the results of the experiment to their neurophysiological and neuromedical application in terms of enhancing anamnesis and taking into account post-correction data in subsequent medical treatment.</p

Polarity in GaN and ZnO: Theory, measurement, growth, and devices

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Rev. 3, 041303 (2016) and may be found at https://doi.org/10.1063/1.4963919.The polar nature of the wurtzite crystalline structure of GaN and ZnO results in the existence of a spontaneous electric polarization within these materials and their associated alloys (Ga,Al,In)N and (Zn,Mg,Cd)O. The polarity has also important consequences on the stability of the different crystallographic surfaces, and this becomes especially important when considering epitaxial growth. Furthermore, the internal polarization fields may adversely affect the properties of optoelectronic devices but is also used as a potential advantage for advanced electronic devices. In this article, polarity-related issues in GaN and ZnO are reviewed, going from theoretical considerations to electronic and optoelectronic devices, through thin film, and nanostructure growth. The necessary theoretical background is first introduced and the stability of the cation and anion polarity surfaces is discussed. For assessing the polarity, one has to make use of specific characterization methods, which are described in detail. Subsequently, the nucleation and growth mechanisms of thin films and nanostructures, including nanowires, are presented, reviewing the specific growth conditions that allow controlling the polarity of such objects. Eventually, the demonstrated and/or expected effects of polarity on the properties and performances of optoelectronic and electronic devices are reported. The present review is intended to yield an in-depth view of some of the hot topics related to polarity in GaN and ZnO, a fast growing subject over the last decade

FDR Stabilizer Selection Using Simple Soil Tests

69A355184710Most local agencies that use full-depth reclamation (FDR) choose the stabilizer to be used by selecting a vendor rather than performing test on the pavement materials. Most of the methods available for selecting the technique or additive to be used rely on a sieve test and the plastic index (PI). The PI is not sensitive at the low values found in materials like the glacial tills common across the northeast. However the Sand Equivalent (SE) is more sensitive in those materials and can be performed quickly. Five soils were tested to see if the SE with a sieve test could be used to discern if asphalt emulsion would be a good stabilizer additive for FDR. A proposed new matrix for which stabilizer technique or additive was proposed. Three sets of pavement materials (surface asphalt concrete and base gravels) were then tested to confirm the proposed stabilizer selection matrix. The results confirmed that the SE test may be a good alternative for local agencies trying to decide which stabilizer to use

Total Aortic Arch Replacement: Superior Ventriculo-Arterial Coupling with Decellularized Allografts Compared with Conventional Prostheses.

BACKGROUND: To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts. METHODS: After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group). Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure-conductance catheter. From the hemodynamic variables end-systolic elastance (Ees), arterial elastance (Ea) and ventriculoarterial coupling were calculated. Characteristic impedance (Z) was assessed by Fourier analysis. RESULTS: While Ees did not differ between the groups and over time (4.1+/-1.19 vs. 4.58+/-1.39 mmHg/mL and 3.21+/-0.97 vs. 3.96+/-1.16 mmHg/mL), Ea showed a higher increase in the prosthesis group (4.01+/-0.67 vs. 6.18+/-0.20 mmHg/mL, P<0.05) in comparison to decellularized allografts (5.03+/-0.35 vs. 5.99+/-1.09 mmHg/mL). This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5+/-50.9 vs. 3.9+/-23.4%). Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6+/-8.3dyn.sec.cm-5 vs. 32.4+/-2.0dyn.sec.cm-5, P<0.05). CONCLUSIONS: Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving ventriculoarterial mechanoenergetics after aortic arch replacement

MicroRNAs in vascular tissue engineering and post-ischemic neovascularization

Increasing numbers of paediatric patients with congenital heart defects are surviving to adulthood, albeit with continuing clinical needs. Hence, there is still scope for revolutionary new strategies to correct vascular anatomical defects. Adult patients are also surviving longer with the adverse consequences of ischemic vascular disease, especially after acute coronary syndromes brought on by plaque erosion and rupture. Vascular tissue engineering and therapeutic angiogenesis provide new hope for these patients. Both approaches have shown promise in laboratory studies, but have not yet been able to deliver clear evidence of clinical success. More research into biomaterials, molecular medicine and cell and molecular therapies is necessary. This review article focuses on the new opportunities offered by targeting microRNAs for the improved production and greater empowerment of vascular cells for use in vascular tissue engineering or for increasing blood perfusion of ischemic tissues by amplifying the resident microvascular network

A computational model for prediction of clot platelet content in flow-diverted intracranial aneurysms

Treatment of intracranial aneurysms with flow-diverting stents is a safe and minimally invasive technique. The goal is stable embolisation that facilitates stent endothelialisation, and elimination of the aneurysm. However, it is not fully understood why some aneurysms fail to develop a stable clot even with sufficient levels of flow reduction. Computational prediction of thrombus formation dynamics can help predict the post-operative response in such challenging cases. In this work, we propose a new model of thrombus formation and platelet dynamics inside intracranial aneurysms. Our novel contribution combines platelet activation and transport with fibrin generation, which is key to characterising stable and unstable thrombus. The model is based on two types of thrombus inside aneurysms: red thrombus (fibrin- and erythrocyte-rich) can be found in unstable clots, while white thrombus (fibrin- and platelet-rich) can be found in stable clots. The thrombus generation model is coupled to a CFD model and the flow-induced platelet index (FiPi) is defined as a quantitative measure of clot stability. Our model is validated against an in vitro phantom study of two flow-diverting stents with different sizing. We demonstrate that our model accurately predicts the lower thrombus stability in the oversized stent scenario. This opens possibilities for using computational simulations to improve endovascular treatment planning and reduce adverse events, such as delayed haemorrhage of flow-diverted aneurysms